[Federal Register: April 18, 2008 (Volume 73, Number 76)]
[Rules and Regulations]
[Page 21181-21209]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr18ap08-12]
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Part III
Department of Labor
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Mine Safety and Health Administration
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30 CFR Part 75
Sealing of Abandoned Areas; Final Rule
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DEPARTMENT OF LABOR
Mine Safety and Health Administration
30 CFR Part 75
RIN 1219-AB52
Sealing of Abandoned Areas
AGENCY: Mine Safety and Health Administration (MSHA), Labor.
ACTION: Final rule.
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SUMMARY: This final rule revises MSHA's Emergency Temporary Standard
(ETS) and addresses sealing abandoned areas in underground coal mines.
The final rule includes requirements for seal strength, design,
construction, maintenance and repair of seals and monitoring and
control of atmospheres behind seals in order to reduce the risk of seal
failure and the risk of explosions in abandoned areas of underground
coal mines. It also addresses the level of overpressure for new seals.
EFFECTIVE DATE: This final rule is effective April 18, 2008.
FOR FURTHER INFORMATION CONTACT: Patricia W. Silvey, Director, Office
of Standards, Regulations, and Variances, MSHA, 1100 Wilson Blvd., Room
2350, Arlington, Virginia 22209-3939, silvey.patricia@dol.gov (e-mail),
(202) 693-9440 (voice), or (202) 693-9441 (telefax).
SUPPLEMENTARY INFORMATION:
The outline of the final rule is as follows:
I. Background
II. Discussion of the Final Rule
III. Section-by-Section Analysis
IV. Executive Order 12866
A. Mine Sector Affected
B. Benefits
C. Compliance Costs
V. Feasibility
A. Technological Feasibility
B. Economic Feasibility
VI. Regulatory Flexibility Act and Small Business Regulatory
Enforcement Fairness Act
A. Definition of Small Mine
B. Factual Basis for Certification
VII. Paperwork Reduction Act of 1995
A. Summary
B. Details
VIII. Other Regulatory Considerations
A. The Unfunded Mandates Reform Act of 1995
B. The Treasury and General Government Appropriations Act of
1999: Assessment of Federal Regulations and Policies on Families
C. Executive Order 12630: Government Actions and Interference
With Constitutionally Protected Property Rights
D. Executive Order 12988: Civil Justice Reform
E. Executive Order 13045: Protection of Children From
Environmental Health Risks and Safety Risks
F. Executive Order 13132: Federalism
G. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
I. Executive Order 13272: Proper Consideration of Small Entities
in Agency Rulemaking
IX. References
I. Background
In the Federal Coal Mine Health and Safety Act of 1969 (Coal Act),
the predecessor to the existing Mine Act, Congress first recognized
that mine operators must isolate abandoned areas of underground coal
mines from active workings for the protection of miners' safety:
In the case of mines opened on or after the operative date of
this title, or in the case of areas developed on or after such date
in mines opened prior to such date, the mining system shall be
designed, in accordance with a plan and revisions thereof approved
by the Secretary and adopted by the operator, so that, as each set
of cross entries, room entries, or panel entries of the mine are
abandoned, they can be isolated from active workings of the mine
with explosion-proof bulkheads.
Pub. Law 91-173 (Dec. 1969) Section 303(2)(3).
In the conference report filed in the House, the statement of the
managers on the part of the House stated, regarding the requirement
that an abandoned area of a mine either be ventilated or sealed, that:
[t]he determination of which method [(ventilated or sealed)] is
appropriate and the safest at any mine is up to the Secretary or
[her] inspector to make, after taking into consideration the
conditions of the mine, particularly its history of methane and
other explosive gases. The objective is that [s]he require the means
that will provide the greatest degree of safety in each case. * * *
When sealing is required, such sealing shall be made in an approved
manner so as to isolate with explosion-proof bulkheads such areas
from the active working of the mine.
Under the conference substitute, paragraph (3) of section 303(z)
provides that, in the case of mines opened on or after the operative
date of this title, or in the case of areas developed on or after
such date in mines opened prior to such date, the mining system
shall be designed, in accordance with a plan and revisions thereof
approved by the Secretary and adopted by the operator, so that, as
each set of cross entries, room entries, or panel entries of the
mine are abandoned, they can be isolated from active workings of the
mine with explosion-proof bulkheads approved by the Secretary or his
inspector.
The managers expect the Secretary to take the lead in improving
technology in this area of controlling methane accumulations in gob
areas and to improve upon this important section 303(z).
Conf. Rep. No. 91-761, 91st Cong. 1st Sess., 82 (Dec. 16, 1969)
(statement of the managers on part of the House) (emphasis added).
The Mine Act interim mandatory standards required seals to be
``made in an approved manner so as to isolate with explosion-proof
bulkheads such areas from the active workings of the mine.'' 30
U.S.C.863(z)(2).
On May 15, 1992, as part of a comprehensive revision of its
standards for ventilation of underground coal mines, MSHA published
standards for construction of seals in Sec. 75.335 of the ventilation
standards (57 FR 20868). The standard required seals to be constructed
of solid concrete blocks at least six inches by eight inches by sixteen
inches, but allowed seals to be constructed using alternative methods
and materials, provided, among other things, that the seal was capable
of withstanding a horizontal static pressure of 20 psi. MSHA based this
threshold on a U.S. Bureau of Mines 1971 report entitled ``Explosion--
Proof Bulkheads--Present Practices.''
A number of manufacturers developed materials, such as cementitious
foams and glass-fiber material, which were tested and subsequently
deemed suitable for use in alternative seals and marketed under various
trade names. MSHA required the manufacturers to have full-scale seals
be subjected to explosion testing at the National Institute for
Occupational Safety and Health (NIOSH) Lake Lynn Experimental Mine
(Lake Lynn). MSHA then intended for mine operators to construct seals
as constructed and tested at Lake Lynn.
On January 2, 2006, an explosion at the Sago Mine in Upshur County,
West Virginia caused the death of twelve miners. Later that year, on
May 20, 2006, an explosion at the Darby Mine No. 1 in Harlan County,
Kentucky, caused the death of five miners. Common to both of these
accidents was the failure of the seals in the mine. The failed seals in
both mines were constructed with the same approved alternative material
for a 20-psi seal. None of the failed seals were constructed in the
same manner as they were constructed at Lake Lynn. Therefore, MSHA
issued a moratorium on alternative methods and materials for
construction of new seals (Program Information Bulletin (PIB) No. P06-
11, June 1, 2006, reissued on June 12, 2006 as PIB No. P06-12, reissued
on June 21, 2006 as PIB No. PO6-14).
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Following these underground coal mine disasters in 2006, Congress
passed and the President signed the MINER Act. Section 10 of the MINER
Act requires the Secretary of Labor to finalize mandatory health and
safety standards relating to the sealing of abandoned areas in
underground coal mines, and to increase the 20 psi standard.
MSHA increased the strength of alternative seals to 50 psi and
addressed a number of other issues related to the construction and the
effectiveness of existing alternative and solid concrete block seals in
Program Information Bulletin No. P06-16, ``Use of Alternative Seal
Methods and Materials Pursuant to 30 CFR 75.335(a)(2),'' issued on July
19, 2006 (July 2006 PIB).
On February 8, 2007, NIOSH issued a draft report, ``Explosion
Pressure Design Criteria for New Seals in U.S. Coal Mines'' (2007 NIOSH
Draft Report). The draft report states that ``mine seals and their
related systems such as the monitoring, inertization and ventilation
systems require the highest level of engineering and quality assurance.
Successful implementation of the seal design criteria and
recommendations in this report should reduce the risk of seal failure
due to explosions in abandoned areas of underground coal mines.'' (2007
NIOSH Draft Report at 40). In the executive summary of the draft
report, NIOSH made recommendations for formulating seal design
criteria.
On May 22, 2007, MSHA published an Emergency Temporary Standard;
notice of public hearings; and notice of close of comment period (72 FR
28796). The comment period, scheduled to close on July 6, 2007, was
extended to August 17, 2007 (72 FR 34609) and four public hearings were
held. The hearings were held on July 10, 2007, in Morgantown, West
Virginia; on July 12, 2007, in Lexington, Kentucky; on July 17, 2007,
in Denver, Colorado; and on July 19, 2007, in Birmingham, Alabama.
On August 14, 2007, MSHA extended the comment period to September
17, 2007, (72 FR 45358) to allow commenters additional time to review
recently posted documents on MSHA's Web site and a recently published
report from NIOSH entitled ``Explosion Pressure Design Criteria for New
Seals in U.S. Coal Mines,'' NIOSH Publication No. 2007-144, July 2007,
IC-9500 (2007 NIOSH Final Report). With one exception, the final
version of this report was little changed from the draft version of
this report that was referenced in the ETS. The final report includes a
new section 3.3, Homogeneous Methane-Air Mixtures in Sealed-Area
Atmospheres. This new section discusses methane layering in sealed
areas and asserts that gaseous diffusion will result in a relatively
homogeneous mixture within a matter of days after sealing. Other minor
changes are related to rounding to metric units (sample pipes should
extend 16 feet (5 meters) into the sealed area) and the inclusion of
recent NIOSH research on methane flammability that lists the
flammability range of methane-air mixtures at sea level as 5.0 percent
to 16.0 percent methane.
On December 7, 2007, MSHA posted on the Agency's Web site the U.S.
Army Corps of Engineer's Draft Report ``CFD [Computational Fluid
Dynamics] Study and Structural Analysis of the Sago Mine Accident''
(USACE's Draft Report). The Agency placed the Report in the rulemaking
record for the ETS on Sealing of Abandoned Areas. The Report summarizes
the preliminary results of a study performed by the USACE under
contract (MSHA NO IA-AR 600012) for MSHA's Technical Support
Directorate (Technical Support). The USACE conducted research from
August 2006 to April 2007. The USACE provided a draft of the Report of
their findings to Technical Support in May of 2007. The Report details
the USACE's efforts to mathematically model the methane explosion at
the Sago Mine and potentially establish the seal overpressures.
On December 19, 2007, MSHA published a notice (72 FR 71791) to
reopen the comment period; announce availability of the USACE's Draft
Report; schedule a public hearing; and announce the close of the
comment period. A public hearing was held in Arlington, Virginia on
January 15, 2008 and the comment period closed on January 18, 2008.
In developing this final rule, MSHA considered the investigation
reports of the Sago and Darby mine explosions, implementation and
enforcement experience under the ETS, MSHA's in-mine seal evaluations
and review of technical literature, the 2007 NIOSH Draft and Final
Reports on explosion testing and modeling, the USACE's Draft Report,
accident reports, research studies, public comments, hearing
transcripts and supporting documentation from all segments of the
mining community.
II. Discussion of the Final Rule
This final rule assures that miners can rely on seals to protect
them from the hazardous and sometimes explosive environments within
sealed areas. This final rule includes requirements for seal strengths;
design applications and installation; sampling and monitoring of sealed
atmospheres; construction and repair of seals, training for persons
conducting sampling and persons constructing or repairing seals, and
recordkeeping to protect miners from hazards of sealed areas.
Underground coal mines are dynamic work environments in which the
working conditions can change rapidly. Caved, mined-out areas may
contain coal dust and accumulated gas which can be ignited by rock
falls, lightning, and in some instances, fires started by spontaneous
combustion. Seals are used to isolate this environment from the active
workings of the mine. Seals are also installed to withstand
overpressures resulting from explosions in abandoned areas and to
prevent the potentially explosive methane/air mixtures from migrating
to the working areas. Overpressure is the pressure above the background
atmospheric pressure. For example, air pressure in a car tire is
measured with a pressure gauge as 30 psi, which is an overpressure. The
absolute pressure of the air inside the tire is 44.7 psi which is 14.7
psi or one atmosphere higher. Explosion pressures are normally
expressed as an overpressure beyond standard atmospheric pressure.
A methane/air mixture becomes explosive when 5 percent to 15
percent methane is present with at least a 12 percent oxygen
concentration. If an ignition source is available, then an explosion
can occur and create overpressures. The homogeneity of the methane/air
mixture contributes to the magnitude of the explosion. The homogeneity
of the methane/air mixture can vary depending on the elevation and the
methane liberation of the sealed area and outside factors such as the
temperature and barometric pressure. The speed of an explosion and the
physical characteristics of a sealed area can increase the force of the
explosion such that detonations and significant pressure piling may be
possible.
Pressure piling is the development of pressure in excess of normal
atmospheric pressures as a result of the velocity-related compression
of the gases in front of the flame. Pressure piling results from the
rapid acceleration of the front of the flame. This acceleration process
may be increased by cross-sectional restrictions, obstructions and
other irregularities in the path of the flame. If the air flow ahead of
the front of the flame is sufficiently turbulent, the flame speed may
increase and transition from deflagration to detonation. A detonation
occurs when the flame of an explosion propagates through the unburned
fuel at
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a velocity exceeding the speed of sound. A deflagration occurs when the
flame of an explosion propagates through unburned fuel at a velocity
below the speed of sound.
This final rule addresses seal strength design, construction,
maintenance and repair of seals and monitoring and control of
atmospheres behind seals in order to reduce the risk of seal failure
and the risk of explosions in abandoned areas of underground coal
mines. It also addresses the level of overpressure for new seals. This
final rule will protect miners from hazards of sealed areas.
III. Section-by-Section Analysis
A. Section 75.335 Seal Strengths, Design Applications, and Installation
The final rule addresses the requirements for seal strengths,
design applications, and seal installation.
1. Section 75.335(a) Seal Strengths
Final Sec. 75.335(a) requires that seals constructed in
underground coal mines after October 20, 2008 be designed, constructed
and maintained in accordance with the provisions of this final rule.
Final Sec. 75.335(a)(1)(i), like the ETS, requires that seals
withstand at least 50-psi overpressure when the atmosphere in the
sealed area is monitored and maintained inert. Final Sec.
75.335(a)(1)(i) adds new requirements that these seals be designed
using a pressure-time curve with an instantaneous overpressure of at
least 50 psi, and that the minimum overpressure must be maintained for
at least four seconds and then released instantaneously.
Final Sec. 75.335(a)(1)(ii) addresses new requirements that seals
constructed to separate the active longwall panel from the longwall
panel previously mined be designed using a pressure-time curve with a
rate of pressure rise of at least 50 psi in 0.1 second, and that a
minimum overpressure of at least 50 psi be maintained.
Final Sec. 75.335(a)(2)(i) revises the ETS and requires that seals
withstand overpressures of at least 120 psi if the atmosphere in the
sealed area is not monitored, is not maintained inert, and the
conditions in final Sec. 75.335(a)(3)(i) through (iii) of this section
are not present. Final Sec. 75.335(a)(2)(i) also adds new requirements
that these seals be designed using a pressure-time curve with an
instantaneous overpressure of at least 120 psi, and that a minimum
overpressure of 120 psi be maintained for at least four seconds and
then released instantaneously.
Final Sec. 75.335(a)(2)(ii) adds new requirements that seals
constructed to separate the active longwall panel from the longwall
panel previously mined be designed using a pressure-time curve with a
rate of pressure rise of 120 psi in 0.25 second, and that a minimum
overpressure of 120 psi be maintained.
Final Sec. 75.335(a)(3) is essentially unchanged from the ETS. It
requires seals to withstand overpressures greater than 120 psi if the
atmosphere in the sealed area is not monitored and is not maintained
inert, and either (i) the atmosphere in the sealed area is likely to
contain homogeneous mixtures of methane between 4.5 percent and 17.0
percent and oxygen exceeding 17.0 percent throughout the entire area;
or (ii) pressure piling could result in overpressures greater than 120
psi in the area to be sealed; or (iii) other conditions are
encountered, such as the likelihood of a detonation in the area to be
sealed.
Final Sec. 75.335(a)(3)(iv) retains the ETS requirement that when
homogenous explosive atmospheres, pressure piling or the likelihood of
a detonation exists, the mine operator must revise the ventilation plan
to address the potential hazards. In addition, the operator must
conduct an analysis of the mining conditions and revise the plan to
include seal strengths sufficient to address these conditions.
MSHA received many comments in response to its request on the
appropriateness of the three-tiered approach to seal strength in the
ETS. One commenter stated that the strength requirements in the first
and second tier are arbitrary. Other commenters objected to the fixed
seal strengths and requested that either a case-by-case determination
or a risk analysis be made to determine which seal strength is needed.
One commenter suggested that a two-tiered approach is adequate and that
a third tier is not needed. A commenter stated that the 120-psi value
proposed in the ETS is sufficient for design purposes and that the 120-
psi load prescribed by the ETS is the highest design criterion for
seals among all the coal producing countries. Another commenter stated
that an explosion with a force greater than 120 psi could not occur in
an underground coal mine. Other commenters, however, stated that
greater than 120-psi explosion pressures can occur in sealed areas.
Some commenters suggested that a 640-psi seal, as recommended by NIOSH,
should be included in the standard. One commenter on the USACE's Draft
Report stated that MSHA should consider a provision in the final rule
that would assure that seals are explosion-proof.
The Agency believes that a risk based analysis to determine seal
strengths on a case-by-case basis rather than the tiered approach is
not appropriate for several reasons. In the ETS, the Agency requested
comments on alternatives to the seal strength requirements in the ETS,
including supporting data, feasibility, and costs. MSHA did not receive
any specific information, relative to alternatives requested, that
would support a risk-based analysis on a case-by-case basis in this
final rule. The rulemaking record contains little information
supporting a case for risk analysis or costs and feasibility of such an
approach. Commenters did not address how risk analysis on a case-by-
case basis would impact the final rule and miner safety. Since the
rulemaking record does not support this alternative approach to
determine seal strengths, MSHA has not included it in this final rule.
The strength requirements for final Sec. 75.335(a) are based on
MSHA's investigation of the explosion at the Sago mine and the 2007
NIOSH Final Report. NIOSH discovered through research testing and
modeling that a 50-psi peak overpressure could occur in a limited-
volume, unconfined situation. Small, unconfined pockets of gases in an
explosive concentration could always exist in a sealed area. If any of
these pockets were ignited, a 50-psi pressure pulse could be generated.
In addition, NIOSH stated that a 120-psi peak pressure could occur
in a limited, confined-volume situation. According to NIOSH, in such a
situation, even if the overall concentration of explosive gases in the
gob is well above the explosive concentration, explosive concentrations
could be present in some areas. NIOSH further stated that if an
explosive mix of methane and oxygen is ignited in this situation, an
explosion could generate a peak explosion pressure of 120-psi. Based on
the 2007 NIOSH Final Report and the Agency's data and experience, this
final rule retains the second tier of the ETS.
Unlike NIOSH's design curves for 50-psi and 120-psi overpressures,
NIOSH did not recommend a static approximation to the 640-psi pressure-
time curve because ``Additional studies are required * * *.'' (2007
NIOSH Final Report at pg. 61). Although the NIOSH 640-psi pressure-time
curve could be used to design seals, in this case a dynamic analysis
would have to be conducted by the professional engineer. MSHA
considered NIOSH's 640-psi seal design. However, a prescriptive
specific dynamic load factor based on the 640-psi design was not
determined and
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requires further studies as stated in the 2007 NIOSH Final Report. As
stated in the ETS, ``Although the recommended maximum seal strength in
the 2007 NIOSH Draft Report is 640 psi, MSHA has no empirical or other
data at this time, demonstrating that mine conditions exist that will
necessitate seals stronger than 120 psi.'' One commenter on the USACE's
draft report questioned this statement. MSHA stated in a Memorandum
from its Office of Technical Support that ``these comparisons [between
the USACE Report and known conditions after the Sago Mine explosion]
again brought the practical applicability of results of the study into
question.'' The Memorandum further states that: ``Technical Support
decided not to publish the study because the critical information
necessary to develop an accurate simulation was not available, and
therefore, any results could not be relied upon for decision-making.
Much of the data provided to the USACE for the three simulations
described in the draft report was speculative * * *''
Based on the Agency's available information and data, MSHA could
not specifically recommend a 640-psi strength requirement. The final
rule retains the third tier of the ETS and requires a seal stronger
than 120 psi if certain conditions are encountered. Under the final
rule, mine operators must perform a risk analysis and evaluate the
atmosphere of the area to be sealed and determine when higher pressure
seals should be used and at what strength. The seal design must be
approved at the appropriate strength for the specific conditions to be
encountered.
Most commenters expressed concern that under the ETS, it is
virtually impossible to determine when the conditions requiring a seal
greater than 120 psi are present. MSHA has structured the final rule to
accommodate pressures greater than 120 psi in recognition of the fact
that explosion pressures may exceed this limit under certain
conditions. These conditions would be a concern only in sealed areas
that are not monitored and not maintained inert. The final rule
requires seal strengths greater than 120 psi if seals are constructed
around areas that are not monitored and are not inert, and one of the
following three conditions occurs: (1) A homogeneous explosive
atmosphere exists, (2) pressure piling could result in pressures
exceeding 120 psi, or (3) detonation is likely.
MSHA expects that mine operators will sample an appropriate number
of locations within the sealed area during the period when seals are
reaching their design strength to address whether a homogeneous
explosive atmosphere exists. These samples could be taken at various
locations, including through seals constructed around the sealed area
and possibly through boreholes or shafts within the sealed area. When
these seals reach design strength of 120 psi, sampling is no longer
required. If the methane concentration stabilizes between 4.5 percent
and 17 percent and the oxygen concentration remains above 17 percent in
all samples, then the atmosphere is considered homogeneous throughout
the sealed area, and seal strengths must be designed to an adequate
level above 120 psi, as determined by the professional engineer, which
will provide adequate protection for miners underground. MSHA realizes
that the seals surrounding the sealed area must be in place prior to
sampling.
MSHA expects that mine operators will evaluate the physical
characteristics of the underground workings near all seals surrounding
the sealed area to address whether pressure piling can occur to a
degree that causes explosion overpressures to exceed 120 psi.
Overpressures that occurred during the 2006 explosion at the Sago Mine
increased in magnitude due to a severe change in the physical
characteristics of the underground workings near the seals. The seals
at the Sago Mine were constructed to a height of approximately 7 feet.
The workings in the sealed area had been previously second mined to a
height of nearly 20 feet in some locations near the seals. As the
explosion propagated toward the seals, pressure piling occurred and
caused excessive pressure at the location of the seals. These factors
must be considered by the mine operator to determine if a situation
exists that will cause pressure piling, resulting in pressures above
120 psi. If this situation exists, then seal strengths must be designed
to an adequate level above 120 psi, as determined by the professional
engineer.
MSHA expects that mine operators will fully evaluate potential
ignition sources, potential methane concentrations, and potential
oxygen concentrations in the sealed areas to determine if detonation
could occur. Mine operators should consider whether a high energy
ignition source exists in the sealed area, whether extensive volumes of
homogeneous mixtures of explosive methane concentrations may exist, and
whether sufficient oxygen may be present in the sealed area.
MSHA received several comments on the USACE's Draft Report. The
report details the USACE's efforts to mathematically model the methane
explosion at the Sago Mine and potentially establish the seal
overpressures. The report recommended that additional research was
needed to refine the models in order to better predict an explosion
pattern.
Commenters stated that computational fluid dynamics modeling could
be used effectively to compare the effect of different variables on
explosions, but that this type of modeling cannot accurately predict
conditions. According to one commenter, their data collection and
analysis of an actual gob composition is highly non-homogeneous, and
the chance of methane gas detonation in a coal mine is almost zero.
Therefore, this commenter stated that the 120-psi criterion in the ETS
is adequate.
Final Sec. Sec. 75.335(a)(1)(i) and (a)(2)(i) include requirements
that seal designs must resist explosions of specific duration and
intensity. The duration and intensity is characterized in pressure-time
curves. A pressure-time curve gives engineers a mechanism to perform a
dynamic analysis or to derive a dynamic load factor that they can use
in a static analysis of a design. The pressure-time curves in Figures 1
and 2 yield a dynamic load factor (DLF) of 2.0, which is the
theoretical maximum (Structures to Resist the Effects of Accidental
Explosions, Department of the Army, Report TM 5-1300, November 1990)
(1990 Department of the Army Report). Holding the applied pressure for
at least four seconds assures that a seal could be loaded elastically
at a DLF of 2.0 (1990 Department of the Army Report). The instantaneous
release of the overpressure load after at least four seconds gives
engineers a criterion to address the rebound effect that would occur in
the seal after the explosive force was removed. Under this final rule,
a professional engineer could submit, for MSHA approval, a unique
design that is able to withstand the prescribed design criteria.
Figures 1 and 2 are the 50-psi and 120-psi pressure-time curves to
be used for seal design.
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Several commenters requested a more prescriptive design standard
identifying minimum overpressures. MSHA believes that a more
prescriptive standard would eliminate ambiguity and result in greater
protection of miners. In response to these comments and for clarity,
final Sec. Sec. 75.335(a)(1)(i) and (a)(2)(i) provide specific
pressure-time curves for certain seal designs.
Some commenters requested that they be allowed to use seals
constructed to separate the active longwall panel from the longwall
panel previously mined. These commenters stated that such seals protect
miners from explosions and help control spontaneous combustion, which
has historically been a problem in the western U.S. mines. MSHA's
enforcement policy under the ETS is consistent with the prescriptive
design requirements in final Sec. Sec. 75.335(a)(1)(ii) and (a)(2)(ii)
for these types of seals. These provisions allow seals to be designed
using pressure-time curves that characterize an explosion having
pressure venting and slower pressure rise times. Such pressure-time
curves are published in the 2007 NIOSH Final Report.
Both NIOSH 50-psi and 120-psi pressure-time curves for these seals
yield a dynamic load factor of 1.0. The caved roof gob adjacent to
seals used to separate the active longwall panel from the longwall
panel previously mined minimizes run-up distances, which may otherwise
be long enough to generate steeper rise times on either pressure pulse.
Thus, both pressure-time curves enable engineers to analyze these seal
designs based upon a dynamic analysis or a static, uniform pressure,
which is equal to the peak overpressure in the applicable pressure-time
curve. Figures 3 and 4 are the 50-psi and 120-psi pressure-time curves
that can be used for the design of seals that separate the active
longwall panel from the longwall panel previously mined.
[[Page 21187]]
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[GRAPHIC] [TIFF OMITTED] TR18AP08.012
Several commenters asked that explosion wave mitigation procedures
be allowed in lieu of seal designs to withstand overpressures greater
than 120-psi. Based on MSHA's knowledge and experience, if a seal is to
withstand overpressures at the design seal strength, then wave
mitigation methods may not provide effective protection. Most wave
mitigation techniques are designed for a one-time use, after which they
do not offer any quantifiable resistance to explosion overpressure.
While wave mitigation methods are not discouraged by MSHA, wave
mitigation alone cannot be used to meet the requirements of the
standard.
Several commenters inquired about a safety factor in the seal
designs. Some commenters believed that the seal design requirement in
the ETS included a safety factor of two. Like the ETS, this final rule
does not require a safety factor in any seal designs. As mentioned
above, for static-equivalent seal designs using either of the two
prescribed pressure-time curves having an instantaneous rise, a Dynamic
Load Factor (DLF) of 2 would be applied to the peak overpressure. The
DLF is multiplied by the peak overpressure for a static-equivalent
overpressure for which the seal should be designed to resist. For
example, a 120-psi seal designed with a static-equivalent procedure
would have to withstand a design static overpressure of 240 psi. The
two prescribed pressure-time curves that are permitted for use with
seals constructed to separate the active longwall panel from the
longwall panel previously mined have a DLF of 1. A DLF is not a factor
of safety. It is a ratio used to equate a dynamic load with a static
load for design purposes. Professional engineers are expected to
incorporate load factors in their designs, in addition to the DLF, in
accordance with current prudent structural engineering practices.
Many commenters questioned why Mitchell-Barrett seal designs were
not permitted under the ETS. Some commenters stated that Mitchell-
Barrett seals were tested by NIOSH and that they are capable of holding
a static load over 95 psi. This maximum 95 psi overpressure was
generated in a small-volume chamber behind the tested seal and was not
generated by an explosion pressure wave traveling down a mine opening
at the Lake Lynn Experimental Mine, as seals had been tested
previously. NIOSH attempted to establish equivalency of a small-volume
chamber to the full-scale explosion tests. NIOSH did not establish
equivalency between the two types of tests. Also, the pressure-time
curve in this final rule for 50-psi seals incorporates a DLF of 2 and
results in a static equivalent load of 100 psi. This static equivalent
load is greater than the 95 psi static load that NIOSH measured.
Mitchell-Barrett seals that were tested
[[Page 21188]]
by NIOSH would not be permitted under this final rule for 50-psi seals
requiring a DLF of 2.0.
One commenter stated that the ETS would cause existing seals in
three mines operated by the mine operator to be replaced with 50-psi
rated seals and that replacement of the existing seals would be costly.
The final rule does not require replacement of existing seals; rather,
for existing seals, it requires operators to monitor methane and oxygen
concentration levels and to maintain an inert atmosphere in the sealed
area.
Another commenter stated that the turnkey costs for seals used in
the company's mines ranged from $12,000 to $25,000 and stated that MSHA
had severely understated costs. However, the Agency's cost estimates
are weighted averages of the costs for various types of seals. MSHA's
estimated turnkey costs range from approximately $7,370 to $25,000 for
50 psi seals and $11,330 to $38,550 for 120 psi seals. The commenter's
costs come within the range of seal costs MSHA used to develop its cost
estimates.
2. Section 75.335(b) Seal Design Applications
Final Sec. 75.335(b) renumbers and revises ETS Sec. 75.336(a). It
requires that seal design applications be based on either engineering
design applications or full-scale explosion tests. The final rule
permits the applicant to use other equivalent means of physical testing
in lieu of full-scale explosion tests. The final rule also requires
that seal design applications from seal manufacturers or mine operators
be submitted for approval to MSHA's Office of Technical Support,
Pittsburgh Safety and Health Technology Center, P.O. Box 18233,
Cochrans Mill Road, Pittsburgh, PA 15236.
Final Sec. 75.335(b)(1), like the ETS, sets forth specific
requirements for an engineering design application. Under final Sec.
75.335(b)(1)(i), an engineering design application must address the
following: Gas sampling pipes, water drainage systems, methods to
reduce air leakage, pressure-time curve, fire resistance
characteristics, flame spread index, entry size, engineering design and
analysis, elasticity of design, material properties, construction
specifications, quality control, design references, and other
information related to seal construction.
Section 75.335(b)(1)(i) has been revised to include elasticity of
design in the engineering design application. MSHA has included this
requirement in the final rule for clarity. It is based on the 2007
NIOSH Final Report and on MSHA's experience with seal design approvals
under the ETS. NIOSH notes in the 2007 NIOSH Final Report that repeated
pressure waves will likely impact the seal structure. Applications for
seals designed for overpressures of 120 psi or greater must address
elasticity in their design in order to withstand repeated, independent
overpressures. This is consistent with current prudent engineering
practices and with MSHA's seal approval process under the ETS.
Addressing elasticity in seal design does not require a higher seal
strength than that under the ETS. The final rule is consistent with
MSHA's approved seal designs under the ETS. This final rule retains the
other requirements of the ETS.
Final Sec. 75.335(b)(1)(ii), like the ETS, requires that an
engineering design application be certified by a professional engineer
that the design of the seal is in accordance with current, prudent
engineering practices. In addition, it clarifies the ETS requirement
and specifies that the professional engineer certify that the seal
design is applicable to conditions in an underground coal mine. In the
ETS, MSHA discussed the engineering decisions and actions that must be
made by and must be the responsibility of the professional engineer.
Those included (1) the selection or development of design standards or
methods, and materials to be used in seal construction; (2) the
development and preparation of the structural analyses and design
computations, drawings, and specifications; (3) the selection or
development of techniques or methods of testing to be used in
evaluating materials used either during seal construction or following
completion of seal construction; and (4) the development of
construction procedures. This final rule clarifies MSHA's intent that a
seal design must reliably function given a set of specific conditions
in an underground coal mine, and that a professional engineer must
certify that the seal design is applicable to conditions in an
underground coal mine.
Several commenters stated that professional engineers who are
required to comply with the engineering design application requirements
in the ETS could lose complete dominion and control over the design of
a seal. A commenter stated that West Virginia state law requires a
professional engineer to maintain complete direction and control over
all specifications, reports, drawings, plans, design information, and
calculations to be certified. Commenters raised an issue concerning a
seal designed by MSHA but requiring certification by a professional
engineer. Under the ETS, this particular seal approval required a
separate review and certification by a professional engineer before it
could be used. However, the professional engineer may also use that
particular design as basis for a new seal design and submit it to MSHA
for approval.
A commenter stated that the design of mine seals for use in West
Virginia is engineering work and requires that it be done by a
registered West Virginia professional engineer. MSHA accepts the
certification of a professional engineer from any state and allows that
certification to be used in other states. Each state is responsible for
enforcing its rules and regulations.
Another commenter stated that because field conditions change the
professional engineer must be allowed to make the necessary field
changes to meet those conditions in order to protect the public safety.
MSHA acknowledges that some field conditions may change but because of
the importance and complexity of the seal designs, the final rule does
not permit field changes. Like the ETS, the final rule allows the mine
operator to make revisions to the original approved design by
submitting those changes that are certified by a professional engineer
to MSHA's office of Technical Support for approval.
Final Sec. 75.335(b)(1)(iii) revises ETS Sec. 75.336(a)(1)(iii)
and requires that an engineering design application include a summary
of the installation procedures related to seal construction. Based on
MSHA's field experience under the ETS, the requirement for a summary of
installation procedures is more appropriate than that in the ETS for
specific information to be included in a Seal Design Table. Under the
final rule, the summary should include all of the information necessary
to construct a seal including quality control and other necessary
information. The application must list provisions that specify quality
control procedures for construction and include requirements for
material sampling and testing. Material testing should be conducted by
a certified laboratory and by qualified personnel. The certification
for the laboratory must be from a professional organization such as the
International Organization for Standardization (ISO) and the personnel
must be able to demonstrate qualifications to ensure proper quality
control testing. MSHA's experiences under the ETS reveal that some
information included in the seal design application is proprietary.
Although this information is required to be submitted to Technical
Support for evaluation of
[[Page 21189]]
the design, it is not necessary to include it in the ventilation plan
for approval by the District Manager. The requirement for the summary
information will eliminate the need to disseminate any proprietary
information. It will provide the District Manager with information
needed to approve the seal design in the ventilation plan.
Final Sec. 75.335(b)(2) requires that seal design applications can
be based on full-scale explosion tests or equivalent means of physical
testing. During discussions with MSHA on alternatives to full-scale
testing, NIOSH indicated that equivalent testing conditions can be
represented in suitable hydrostatic test chambers similar to those at
the NIOSH Lake Lynn Experimental mine. MSHA believes that an equivalent
means of physical testing, that has at least the same level of
confidence as full-scale explosion testing, is an acceptable means of
compliance and the Agency has included it in the final rule.
Final Sec. 75.335(b)(2)(i), like ETS Sec. 75.336(a)(2)(i),
requires certification by a professional engineer that the testing was
done in accordance with current, prudent engineering practices for
construction in a coal mine. This final rule deletes the requirement in
the ETS that the professional engineer be knowledgable in structural
engineering. MSHA deleted this requirement because there is no
certification available to assure that a professional engineer is
knowledgable in structural engineering. MSHA's experience with seal
design approvals under the ETS reveals that the Professional Engineers
who successfully submit seal designs are knowledgable in structural
engineering. MSHA received one comment on this provision which
recommended the words ``knowledgable in structural engineering'' be
removed.
Final Sec. 75.335(b)(2)(ii), like ETS Sec. 75.336(a)(2)(ii),
requires the applicant to provide technical information related to the
methods and material used to construct and test the seals. MSHA
received no comments on this provision.
Final Sec. 75.335(b)(2)(iii) requires that the application include
supporting documentation. This clarifies ETS Sec. 75.336(a)(2)(iii)
that required proper documentation. The term ``supporting'' more
accurately describes the type of documentation required. This
documentation includes: Engineering analyses, construction drawings and
specifications, and data that address seal material, fire resistance
and flame-spread index. The applicant must establish the materials and
material properties required for adequate seal construction.
Construction documentation is required to assure that the seals are
properly built and reliable to address air leakage, and to verify that
the material properties of the seal will meet the specified strength
criteria. MSHA received no comments on this provision.
Final Sec. 75.335(b)(2)(iv), like ETS Sec. 75.336(a)(2)(iv),
requires the application to include an engineering analysis addressing
differences between the seal support during test conditions and the
range of test conditions in a coal mine. MSHA received no comments on
this provision.
Final Sec. 75.335(b)(2)(v) revises ETS Sec. 75.336(a)(2)(v) and
requires that a summary of the installation procedures be included in
the application. This requires that applicants submit more appropriate
information in the form of a summary of installation procedures rather
than specific information included in a Seal Design Table as required
by the ETS. This summary should include the installation procedures
related to mine specific seal construction. For example, it would
include the maximum entry width and height for which the specific
design is applicable, the specified strength of the seal material, the
thickness of the seal, and the reinforcement and anchorage requirements
for the seal. Additional information may be provided at the discretion
of the Professional Engineer. MSHA received no comments on this
provision.
Final Sec. 75.335(b)(3), like ETS Sec. 75.336(a)(3), provides
that MSHA will notify the applicant if additional information or
testing is required. It also requires the applicant to provide this
information, arrange any additional or repeat tests, and provide prior
notification to MSHA of the location, date, and time of such tests.
MSHA received no comments on this provision.
Final Sec. 75.335(b)(4), like ETS Sec. 75.336(a)(4), provides
that MSHA will notify the applicant, in writing, whether the design is
approved or denied. It also provides that if the design is denied, MSHA
will specify, in writing, the deficiencies of the application, or
necessary revisions. MSHA received no comments on this provision.
Final Sec. 75.335(b)(5), like ETS Sec. 75.336(a)(5), requires
that once the seal design is approved, the approval holder must
promptly notify MSHA, in writing, of all deficiencies of which they
become aware. MSHA received no comments on this provision.
3. Section 75.335(c) Seal installation approval
Final Sec. 75.335(c), like ETS Sec. 75.336(b), requires that the
installation of the approved seal design be approved in the ventilation
plan.
Final Sec. 75.335(c)(1), like the ETS, requires the mine operator
to retain the seal design approval and installation information for as
long as the seal is needed to serve the purpose for which it was built.
One commenter stated the requirement to retain approval and
installation information for an indefinite period places an onerous
burden on both the professional engineer and the mine operator, and
suggested that the final rule include a definite duration for retaining
this information. Based on MSHA's experience under the ETS, the
requirement for approval and installation information provides a
reliable reference should any problems occur during the service life of
the seal. This provides valuable information as to how the seal was
constructed and identifies the person responsible for certifying that
the provisions in the approved seal design were addressed. In some
instances, this information may enable persons to question individuals
responsible for designing and constructing the seal to gain an insight
as to the circumstances surrounding the construction and identify any
problems that may have been encountered during the construction.
Accordingly, this provision remains unchanged from the ETS.
Final Sec. 75.335(c)(2), like the ETS, requires that the mine
operator designate a professional engineer to conduct or have oversight
of seal installation and certify that the provisions in the approved
seal design specified in this section have been addressed and are
applicable to the conditions in the mine. This final rule also requires
that a copy of the certification be submitted to the District Manager
with the information provided in final Sec. 75.335(c)(3) and that a
copy of the certification be retained for as long as the seal is needed
to serve the purpose for which it was built.
One commenter supported this provision and stated that creating
accountability in the construction process is a critical component if
MSHA is to assure that coal operators take very seriously their
obligation to provide a safe workplace with properly designed and
constructed seals.
Several commenters opposed this provision. They stated that the
requirement to conduct or have oversight of seal installation should be
deleted because it would be expensive, difficult because there are many
variables in the construction process, and unnecessary because a mine
operator must also certify construction. Some commenters stated that a
[[Page 21190]]
professional engineer's function is the design of a seal, not oversight
of the construction. Several commenters stated that the provision would
require a professional engineer to be on site prior to, during, and
following construction of every seal to insure that all parameters are
met and that would be unnecessary.
Under the final rule, MSHA does not intend that the professional
engineer take part in the construction process or be at the seal
installation site during the entire construction process. MSHA stated
its intent with respect to this requirement at the public hearings.
MSHA's existing enforcement policy states that the professional
engineer must inspect the set of seals during construction as part of
the oversight and certification required by ETS Sec. 75.336(b)(2). To
accomplish this oversight, MSHA would expect the professional engineer
to: (1) Verify that the seal application is suitable for the specific
conditions, (2) confirm that the site preparation is adequate, (3)
confirm that the workforce is adequately trained to properly build the
seals, (4) verify that the correct materials and procedures are being
used to construct the seal, and (5) confirm that adequate quality
controls are in place and are being followed. The professional engineer
however, does not have to be onsite the entire time that seals are
being built.
Based on the Agency's knowledge and experience, MSHA has determined
that the oversight by the professional engineer, who would be most
familiar with the seal design, will help assure that appropriate seal
design implementation and related analyses are performed properly. In
addition, it will assure that seals are constructed according to the
drawings and specifications of a professional engineer.
Final Sec. 75.335(c)(3), like the ETS, lists specific information
that a mine operator must address in the ventilation plan. The
information will be used by the District Manager to evaluate a seal
installation and determine whether the seal design is appropriate for a
particular site.
Final Sec. 75.335(c)(3)(i), like the ETS, requires that mine
operators include the MSHA Technical Support Approval Number of the
seal design in the ventilation plan. MSHA did not receive any comments
on this section. This final rule is unchanged from the ETS.
Final Sec. 75.335(c)(3)(ii) revises ETS Sec.
75.336(b)(3)(iii)(D). It requires a summary of the installation
procedures for approval to be included in the ventilation plan. This
final rule is derived from the ETS requirement that the mine operator
specify construction techniques for each type of seal. It revises the
ETS requirement to be consistent with the language in final Sec.
75.335(b)(1)(iii). The information required in this final rule,
however, is essentially the same as that required in the ETS. Examples
of information required by this provision include: Maximum entry width
and height for which the design is applicable; specified strength of
the seal; construction steps; and reinforcement and foundation
anchorage requirements. In addition, when frame work is used,
information should specify frame work size, spacing and materials used,
a description of how the frame work is erected, size of other material
used, such as concrete block size, wood products used and spacing, and,
if needed, an anchorage table for rebar showing lengths, hole size, and
other material used with the rebar. If hitching is required,
information should specify hitching location, width and depth,
calibration of equipment where required, sequence of pouring materials
and thickness, sequence and type of roof support used, surface
preparation, a description of the material pouring techniques and how
cold joints may or may not be permitted, set back distances, a diagram
of the water drainage system and air sampling installation, methods for
preventing water retention during the curing process, rockdust removal
from rib at the seal site, thickness of the seal, and other additional
information in the seal design application.
Final Sec. 75.335(c)(3)(iii) revises the ETS. It requires that
mine operators provide, in the ventilation plan, a mine map of the area
to be sealed and proposed seal locations that include the deepest
points of penetration prior to sealing. This final rule revises the ETS
by requiring that locations include the deepest points of penetration
prior to sealing. This provision will help assure that the area was
surveyed, a map of the area to be sealed was completed and the map was
submitted by the mine operator. In addition, this final rule requires
that the mine map be certified by a professional engineer or a
professional land surveyor. It revises the ETS by including a
professional land surveyor to certify the mine map to be consistent
with existing Sec. 75.1201 which permits a professional land surveyor
to certify the mine map.
Final Sec. 75.335(c)(3)(iv), like the ETS, requires that mine
operators submit specific mine site information in the ventilation
plan. Final Sec. 75.335(c)(3)(iv)(A) requires that the type of seal be
included in the ventilation plan. MSHA did not receive any comments on
this provision.
Final Sec. 75.335(c)(3)(iv)(B), like the ETS, requires mine
operators to include information in the ventilation plan on the safety
precautions taken prior to seals achieving design strength. Some
commenters stated that this provision should require withdrawal of
miners. According to commenters, this would be consistent with NIOSH's
recommendation that miners be withdrawn from the affected area until
seals reach design strength and the atmosphere in the sealed areas
reaches an inert status. Other comments stated that withdrawal is not
necessary because the sealed areas contain no likely ignition source,
and if an inert atmosphere is present, uncured seals do not present an
imminent danger as there is no explosion potential. In addition, some
of these commenters stated that withdrawal of miners during seal curing
time, which could be up to 28 days, would be too costly.
Based on MSHA's knowledge and experience under the ETS, miners
could be exposed to the dangers of an explosion prior to seals
achieving their design strength. Accordingly, MSHA believes that safety
precautions need to be taken prior to seals achieving design strength.
Safety precautions could include withdrawing miners from the entire
mine or other area approved by the District Manager. They could also
include the use of seals that reach their design strength in
considerably less time than 28 days. In addition, the mine operator
could inert the atmosphere prior to or during seal installation. If an
inert atmosphere is present behind seals that have not reached their
design strength, miners would not need to be withdrawn from the
affected area. This provision remains unchanged from the ETS.
Final Sec. 75.335(c)(3)(iv)(C) revises the ETS. It requires that
the mine operator provide information in the ventilation plan on
methods used to address site-specific conditions that may affect the
strength and applicability of the seal, including set-back distances.
The set-back distance, which is the distance from the corner of a
pillar block to a seal, is critical to the long term stability and
protection of a seal. Although the ETS did not specifically address
set-back distances, many professional engineers included this concept
in their design applications.
Based on MSHA's experience under the ETS, professional engineers
designing seals have listed a minimum set-back distance of 10 feet when
applying for a seal design approval in most instances. MSHA believes,
[[Page 21191]]
however, that set-back distances need to be addressed on a mine-by-mine
basis. Some coal is softer or harder than others; and the overburden
varies, which has an effect on the stability of the coal seam pillar.
This means that some coal pillars will remain more or less stable than
others over a long period of time. It is also possible to artificially
reinforce the stability of less stable coal pillars, for example, by
injecting materials into the pillars. Therefore, MSHA is including a
requirement that the set-back distance of a seal be addressed in the
mine ventilation plan during the seal plan approval process.
Final Sec. 75.335(c)(3)(iv)(D), like the ETS, requires the mine
operator to submit information in the ventilation plan on site
preparation. MSHA did not receive any comments on this provision.
Final Sec. 75.335(c)(3)(iv)(E), like the ETS, requires the mine
operator to include information on the sequence of seal installations
in the ventilation plan. MSHA did not receive any comments on this
provision.
Final Sec. 75.335(c)(3)(iv)(F), like the ETS, requires that the
mine operator provide information in the ventilation plan on the
projected date of completion of each set of seals. MSHA did not receive
any comments on this provision.
Final Sec. 75.335(c)(3)(iv)(G), like the ETS, requires the mine
operator to provide information in the ventilation plan on the
supplemental roof support inby and outby each seal. MSHA did not
receive any comments on this provision.
Final Sec. 75.335(c)(3)(iv)(H), like the ETS, requires the mine
operator to provide information in the ventilation plan on the water
flow estimation and dimensions of the water drainage system through the
seals. MSHA did not receive any comments on this provision.
Final Sec. 75.335(c)(3)(iv)(I), like the ETS, requires that the
mine operator provide information in the ventilation plan on the
methods used to ventilate the outby face of seals once completed. MSHA
did not receive any comments on this provision.
Final Sec. 75.335(c)(3)(iv)(J), like the ETS, requires the mine
operator to provide information in the ventilation plan on the methods
and materials used to maintain each type of seal. MSHA did not receive
any comments on this provision.
Final Sec. 75.335(c)(3)(iv)(K), like the ETS, requires the mine
operator to provide information in the ventilation plan on methods used
to address shafts and boreholes in the sealed area. MSHA did not
receive any comments on this provision.
Final Sec. 75.335(c)(3)(iv)(L) is derived from ETS Sec.
75.335(a)(3)(iv). This final rule requires the mine operator to provide
information in the ventilation plan on an assessment of potential for
overpressures greater than 120 psi in the sealed area. ETS Sec.
75.335(a)(3)(iv) required the mine operator to revise the ventilation
plan when conditions that would necessitate a seal greater than 120 psi
are encountered. This final rule is consistent with the ETS. It
includes this provision to assure that the mine operator evaluates the
area to be sealed and addresses the need for seals greater than 120
psi.
Final Sec. 75.335(c)(3)(iv)(M) renumbers and clarifies ETS Sec.
75.335(b)(5)(ii). It requires mine operators to provide information in
the ventilation plan on additional sampling locations. This final rule
is consistent with ETS Sec. 75.335(b)(5)(ii), which required the
location of sampling points to be included in the mine operator's
action plan. Under this final rule, additional sampling locations could
include sampling through boreholes and capped shafts with vent pipes.
Final Sec. 75.335(c)(3)(iv)(N), like the ETS, requires the mine
operator to provide, in the ventilation plan, any additional
information required by the District Manager. This final rule will help
assure that any new developments in technology or any problems related
to site-specific conditions in sealing may be addressed by the mine
operator through the ventilation plan. MSHA did not receive any
comments on this provision.
B. Section 75.336 Sampling and Monitoring Requirements
Final Sec. 75.336, derived from ETS Sec. 75.335(b), revises and
renumbers sampling and monitoring requirements for sealed atmospheres.
In the final rule, the terms ``sampling'' and ``monitoring'' are used
interchangeably. The final rule deletes the requirement in the ETS for
mine operators using seals designed to withstand less than 120 psi to
develop and follow a protocol to monitor methane and oxygen
concentrations in sealed atmospheres. The ETS required that the
protocol be approved by the District Manager in the ventilation plan.
Requirements to maintain and restore an inert atmosphere in the sealed
area are discussed in final Sec. 75.336(b); requirements for sampling
pipes are discussed in final Sec. 75.337(g). Requirements for welding,
cutting and soldering are discussed in final Sec. 75.337(f);
requirements for water drainage systems are discussed in final Sec.
75.337(h); and requirements for training of certified persons
conducting sampling are discussed in final Sec. 75.338(a).
Section 75.336(a) of the final rule retains the requirement in ETS
Sec. 75.335(b) for a certified person, as defined under existing Sec.
75.100, to monitor sealed atmospheres for methane and oxygen
concentrations. Unlike the ETS, the final rule requires sealed
atmospheres to be monitored through each sampling pipe and approved
sampling location whether seals are ingassing or outgassing. Training
requirements for certified persons are addressed in final Sec.
75.338(a) and are unchanged from the ETS.
Final Sec. Sec. 75.336(a)(1)(i) through (iii) address ETS
requirements for sampling frequencies, including initial sampling
periods and sampling on a continuing basis. Atmospheres with seals less
than 120 psi constructed prior to October 20, 2008, and atmospheres
with seals of less than 120 psi constructed after October 20, 2008 must
be sampled through each sampling pipe and approved location at least
every 24 hours. Under the final rule, the operator may request that the
District Manager approve different frequencies and locations in the
ventilation plan. Under the final rule, seals of 120 psi or greater
must be monitored until they reach their design strength. After they
reach their design strength, the final rule does not require the
atmosphere in these sealed areas to be monitored and maintained inert.
Final Sec. 75.336(a)(2) is derived from ETS Sec. Sec.
75.335(b)(1) and (b)(5) and requires the mine operator to evaluate the
atmosphere in the sealed area to determine whether sampling through
required sampling pipes under final Sec. 75.337(g) provides
appropriate sampling locations. The final rule specifies the conditions
under which the evaluation must be conducted. When the evaluation
results indicate the need for additional sampling locations, the mine
operator must establish additional sampling locations and include them
in the ventilation plan for approval by the District Manager.
Final Sec. 75.336(a)(3) requires mine operators with an approved
ventilation plan addressing spontaneous combustion under existing Sec.
75.334(f) to monitor sealed atmospheres in accordance with the plan.
Final Sec. 75.336(a)(4) is derived from ETS Sec. 75.335(b)(5)(vi)
and allows the District Manager to approve the use of a continuous
monitoring system in lieu of monitoring provisions in the final rule.
Final Sec. 75.336(b)(1), like ETS Sec. 75.335(b)(3), defines an
inert atmosphere as one in which the oxygen concentration is less than
10 percent, or
[[Page 21192]]
the methane concentration is less than 3.0 percent or greater than 20.0
percent. Final Sec. 75.336(b)(2) addresses corrective action necessary
if the atmosphere is not inert. It requires that when a sealed
atmosphere with less than 120-psi seals is not inert, the mine operator
must take immediate action to reestablish an inert atmosphere and
monitor the sealed atmosphere every 24 hours until it is restored to an
inert status.
Final Sec. 75.336(c) revises and clarifies ETS Sec. 75.335(b)(4)
and specifies when persons must be withdrawn from the mine due to a
hazardous atmosphere in the sealed area.
Final Sec. 75.336(d) clarifies existing MSHA policy that allows
the operator to request that the District Manager approve in the
ventilation plan a different oxygen concentration if the atmosphere in
the sealed area contains carbon dioxide. It also addresses sealed areas
where inert gas has been injected, and sampling methods and equipment.
Final Sec. Sec. 75.336(e)(1) and (e)(2) are the same as ETS
Sec. Sec. 75.335(b)(6) and (b)(7) and include requirements for
recording sampling results and any hazardous condition found in
accordance with existing Sec. 75.363.
1. Section 75.336(a)
Section 75.336(a) retains the requirement in ETS Sec. 75.335(b)
for a certified person, pursuant to Sec. 75.100, to monitor sealed
atmospheres. The final rule continues to require the certified person
to monitor the sealed area for methane and oxygen concentrations. Under
the final rule, unlike the ETS, sealed atmospheres must be monitored
whether seals are ingassing or outgassing. Mine operators must also
determine the direction of air leakage during monitoring which will
indicate whether seals are ingassing or outgassing. Seals outgas when
the pressure in the sealed area exceeds the pressure on the outby side
of the sealed area. Seals ingas when the pressure outby the sealed area
exceeds the pressure in the sealed area.
ETS Sec. 75.335(b)(1) required mine operators to sample sealed
atmospheres only when seals were outgassing. MSHA requested comments
regarding: its sampling approach; sampling frequency; sampling only
when a seal is outgassing; whether a different sampling approach would
be more appropriate for the final rule, such as when seals are
ingassing; and information and experiences of the mining community
concerning sampling sealed areas.
Commenters' views were divided regarding appropriate conditions for
monitoring seals, especially on the issue of outgassing and/or
ingassing. MSHA received comments in support of the ETS strategy of
requiring monitoring when seals were outgassing, while some other
comments supported monitoring whether outgassing or ingassing. Several
commenters suggested that sampling only during outgassing is inadequate
to protect miners, since a greater concern exists when a seal is
ingassing and adds oxygen to a fuel-rich environment in the sealed
area. One commenter stated that ingassing creates zones of explosive
methane-air mixtures and is more dangerous than when the seals are
outgassing. A number of other commenters stated that sampling inby an
ingassing seal or a seal that is in barometric pressure transition is a
recipe for inaccurate sampling, and MSHA should not require sampling
during ingassing. Finally, one commenter who supported sampling when
seals are outgassing recommended that balance chambers could reduce
incidences of barometric pressure changes exceeding the ventilating
pressure produced by main mine fans causing seals to ingas. According
to this commenter, the sealed atmosphere continues to change at least
at the perimeter of the sealed area, and in some parts of the country,
this change occurs on a daily or even more frequent basis. This
commenter also suggested that MSHA provide incentives for mine
operators such as allowing them to use lower-strength seals than
required in the ETS. According to the commenter, these incentives
should include allowing lower strength seals where balance chambers are
used. MSHA acknowledges that a number of sealed atmospheres fluctuate
from outgassing to ingassing on a frequent basis. MSHA believes that
the sampling strategy under the final rule, based on ingassing or
outgassing, would remove the need for balance chambers.
The Agency has reviewed the comments, hearing transcripts, data and
other information contained in the rulemaking record regarding sampling
and monitoring. MSHA also reviewed the Agency's enforcement history and
field experience with implementation under the ETS. The Agency believes
that sealed atmospheres should be monitored whether outgassing or
ingassing. Since promulgation of the ETS, some operators have
experienced significant delays in monitoring sealed areas, especially
during the 14-day baseline period and while seals are reaching their
design strength. The preamble to the ETS stated:
If the seal is ingassing during the examination, the certified
person must attempt to take a sample during the next weekly
examination. After a second attempt is made and the seal is still
ingassing, attempts must be made daily until the seal outgases. If
repeated sampling indicates that a seal is not likely to outgas,
then the mine operator must submit an alternative protocol to the
District Manager. (72 FR at 28802)
At the time of promulgation of the ETS, MSHA did not envision that
the sampling and monitoring procedure would result in the significant
delays that have been experienced in the mining industry. MSHA
inspectors also experienced delays in monitoring sealed atmospheres
because of having to wait for seals to outgas before a sample could be
taken. Also, limiting monitoring to outgassing affected the operators'
ability to promptly implement the ETS monitoring requirements for
determining whether the sealed atmosphere had reached the explosive
range. After a review of the rulemaking record, the Agency does not
believe that the record evidence supports limiting monitoring sealed
areas to when seals are outgassing. In response to comments and in
light of its own experience, the Agency has revised the monitoring
requirement in this final rule to require mine operators to monitor
sealed atmospheres whether seals are outgassing or ingassing. MSHA
expects the final rule provisions to resolve many existing problems
with monitoring sealed areas and to enhance safety and health of
underground coal miners.
Final Sec. Sec. 75.336(a)(1) requires monitoring through each
sampling pipe and at each approved sampling location. Under Sec.
75.336(a)(1)(i), mine operators must sample atmospheres with seals of
120 psi or greater until the design strength is reached, after which
time they may cease sampling. Initial sampling for all newly-
constructed seals is necessary to protect miners if an explosive
atmosphere forms behind seals before they reach their design strength.
Under Sec. 75.336(a)(1)(ii) of this final rule, like the ETS, the
mine operator must monitor for methane and oxygen and maintain an inert
atmosphere in the sealed area when using seals less than 120 psi
constructed prior to the date of this final rule. Final Sec.
75.336(a)(1)(iii) requires that atmospheres with seals of less than 120
psi constructed after the date of this final rule must be monitored and
the atmosphere must be maintained inert.
Final Sec. Sec. 75.336(a)(1)(ii) and (iii) allow the operator to
request that the District Manager approve different sampling locations
and frequencies in the ventilation plan provided at least one sample is
taken at each set of seals at least every 7 days. Under final
[[Page 21193]]
Sec. 75.335(a)(1)(iii) for less than 120 psi seals constructed after
April 18, 2008, the District Manager cannot approve different sampling
locations and frequencies in the ventilation plan until after a minimum
of 14 days and after seals have reached design strength. MSHA will
consider pertinent information supplied by the mine operator, such as
the results of the 14-day sampling period and any other previous
sampling results, in an operators'' request to change sampling
locations and frequencies. The 7-day interval is the same as the ETS
monitoring frequency and is consistent with weekly examinations
required in existing Sec. 75.364. MSHA believes the sealed atmosphere
must be sampled at least every 7 days in the event seal leakage, strata
fracturing, roof convergence or another problem has developed and is
affecting the sealed atmosphere. Under the final rule, MSHA emphasizes
that mine operators must monitor sealed atmospheres at a frequency of
every 24 hours unless the District Manager approves a different
frequency in the ventilation plan. For newly constructed seals of less
than 120 psi, the final rule requires a 14-day sampling period before
the District Manager may approve different sampling locations and
frequencies. The final rule deletes ETS Sec. 75.335(b)(5)(iii) which
required mine operators to specify procedures in the sampling protocol
to establish a baseline analysis of oxygen and methane concentrations
at each sampling point over a 14-day sampling period to be approved in
the ventilation plan. In the final rule, in response to commenters and
for clarity, MSHA has included specific parameters for sampling sealed
atmospheres. As such, there is no need for a sampling protocol.
Several commenters said that the atmosphere behind all seals should
be monitored and maintained inert. One commenter stated that sealed
areas cannot be adequately monitored or maintained inert; therefore,
all seals must be designed to withstand an explosion. Another commenter
stated that monitoring is inadequate to protect miners and that it
provides a false sense of security. MSHA believes that monitoring
sealed areas informs the mine operator of the presence of potentially
hazardous gases in sealed areas. Under the final rule, use of seals
designed for less than 120-psi overpressure requires the mine operator
to maintain an inert atmosphere in the sealed area since explosions
cannot occur within inert atmospheres. MSHA believes that in mines
which liberate significant volumes of methane, the atmosphere in sealed
areas may become inert naturally. In mines that produce very small
volumes of methane, the atmosphere in sealed areas may never become
explosive. However, some mines may need to use other means to inert the
atmosphere in the sealed area, such as injecting inert gas or pressure
balancing of the ventilation system; or injecting material into the
strata surrounding the seals to reduce leakage. These methods could
inert the atmosphere in the sealed area. Other mines may need to
construct new seals that are 120 psi or greater in front of all
existing seals. MSHA's existing standards at Sec. 75.334(a)(1) and
(a)(2) require that worked-out areas be sealed or ventilated.
Commenters stated that the ETS sampling and monitoring requirements
were confusing. A number of commenters criticized the need for District
Manager approval of the sampling protocol. Several commenters said that
there was no scientific basis for the monitoring, while others said
that the final seal regulation should be more prescriptive. Several
commenters criticized MSHA's weekly sampling intervals as being too
lengthy to protect the miners. One commenter said that their data
showed sealed areas never reach equilibrium and that barometric
pressure changes continue to affect the sealed atmosphere. Commenters
stated that when a sealed area has reached a stable atmospheric
composition, weekly sampling is unnecessary.
MSHA continues to believe that weekly samples are necessary to
protect miners'' safety and health. Barometric pressure changes,
ventilation changes, water accumulations, methane liberation,
subsidence, cracked strata near seals, and other changes may render a
previously inert atmosphere explosive. Periodic monitoring is necessary
to detect these potentially hazardous conditions in the sealed area.
The final rule, like the ETS, requires periodic sampling.
Final Sec. 75.336(a)(2) clarifies MSHA's intent under ETS Sec.
75.335(b) for the mine operator to have responsibility for evaluating
the atmosphere in the sealed area to determine whether sampling through
seal sampling pipes, in accordance with final Sec. 75.337(g), will
provide an appropriate sample of the sealed atmosphere. Appropriate
sampling must be capable of reliably detecting significant
accumulations of explosive methane in the sealed area.
MSHA specifies in the final rule when the mine operator must
conduct the evaluation which includes: the planning phase for sealing
the area; immediately after the minimum 14-day required sampling; when
the mine ventilation system is reconfigured; if changes in the mine
occur that could adversely affect the sealed area; or if the District
Manager requests an evaluation. When the results of the evaluations
indicate the need for additional sampling locations, the mine operator
must provide the additional locations and have them approved in the
ventilation plan. The District Manager may require additional sampling
locations and frequencies in the ventilation plan.
The mine operator shall evaluate the sealed area using the sampling
results from the minimum 14-day required sampling and any other
relevant information available to confirm that the initial evaluation
is valid. A mine ventilation system reconfiguration may affect the
direction of air leakage through seals and consequently alter the
interpretation of sampling results in order to determine the inert
status of the sealed atmosphere. The composition of the sealed
atmosphere can be affected by changes in air currents, water
accumulations, convergence, cracks in the strata leading to the
surface, and the rate and/or location of methane liberation. These
changes may affect the distribution of methane and oxygen concentration
throughout the sealed area. The District Manager may request an
evaluation based on other factors as appropriate.
Many variables affect the atmospheric composition of the sealed
area, including size, methane liberation, leakage, ventilation
pressures, and barometric changes. Mine operators must analyze each
sealed area when determining appropriate sampling locations and
frequencies. If the mine operator's analysis indicates that sampling
through seal sampling pipes does not render an appropriate evaluation
of the sealed atmosphere, the mine operator must establish additional
sampling locations and specify them in the ventilation plan for the
District Manager's approval.
Under the final rule, the District Manager may require additional
sampling locations and sampling frequencies in the mine ventilation
plan such as when MSHA sampling results differ from the operator's
sampling results, or the District Manager's review of the mine
operator's data indicates the atmosphere in the sealed area is not
being adequately evaluated. In the ETS, the Agency expressed its intent
that under ETS Sec. 75.335(b), mine operators had to evaluate the
sealed atmosphere to determine whether additional sampling locations
were necessary.
[[Page 21194]]
In the ETS, MSHA also emphasized that all seals and the strata
around them leak, resulting in an air exchange near the seal during
barometric pressure changes. Seals may leak air into a methane-rich
sealed atmosphere that can result in explosive methane concentrations.
Due to this, MSHA stressed in the ETS the significance of obtaining
appropriate samples of atmospheric conditions in the larger portion of
the sealed area as opposed to the smaller area immediately inby the
seal.
Some commenters objected to the requirement in ETS Sec. 75.335(b)
for the mine operators to obtain a representative sample solely through
sampling pipes. MSHA acknowledges the limitations of the ETS sampling
method for large sealed areas. While sampling a limited number of times
or at a reduced frequency may result in an effective evaluation of the
sealed area, additional sampling locations can be necessary to
determine if a sealed atmosphere is inert. For instance, a sealed
atmosphere may have one set of seals ingassing fresh air from the mine
while another set of seals is outgassing high concentrations of
methane. A transition zone exists where the atmosphere experiences an
explosive range of methane between the two sets of seals. Thus, final
Sec. 75.336(a)(2) addresses the mine operator's responsibility to
include adequate sampling locations and frequencies in the ventilation
plan.
Several commenters stated that it is impractical to drill boreholes
from the surface due to cost implications, surface topography, or land
ownership. Although MSHA recognizes that there may be situations in
which it may be impractical to drill boreholes from the surface, the
Agency is aware that directional drilling from the surface or from
within the mine is commonly practiced in the mining industry and may be
used when topographic or land ownership problems are encountered. It is
common practice in the mining industry to remove all persons from the
affected area when the borehole approaches an unexamined or
unventilated area. Other commenters supported a requirement for drilled
boreholes to adequately monitor large or unusual sealed areas.
A commenter suggested that it is unreasonable for MSHA to assume
that localized samples, regardless of the technique, establish the
inert status of the sealed area. MSHA believes that sampling through
seals, supplemented with additional sampling locations, where
necessary, provides a safe and feasible method of ascertaining
atmospheric conditions in the sealed area. Final Sec. 75.336(a)(2)
provides that the District Manager can require additional sampling
locations, such as boreholes, and frequencies in a mine operator's
ventilation plan.
One commenter expressed that it is not a significant hazard when a
large sealed area in a mine has explosive mixtures when sampled through
pipes, because coalbed methane production wells located above the
sealed area produce almost pure methane (greater than the upper
explosive limit). MSHA believes that methane extracted from the gob
vent borehole primarily comes from the strata above the active coal
mine. (Mucho, T.P., W.P. Diamond, F. Garcia, J.D. Byars and S.L. Cario,
Implications of Recent NIOSH Tracer Gas Studies on Bleeder and Gob Gas
Ventilation Design, The Society of Mining Engineers Annual Meeting,
2000). MSHA determined that boreholes used to sample sealed areas must
be connected to the open entries within the sealed area. Degasification
boreholes typically stop about 30 to 40 feet above the coal seam and do
not extend into the sealed area and will not provide an accurate sample
of the sealed atmosphere.
Some commenters recommended a risk analysis of sealed areas rather
than monitoring. As appropriate, mine operators may include an analysis
of the risks in the sealed area in their evaluation of the sealed area
for MSHA's consideration. An evaluation under final Sec. 75.336(a)(2)
may include size of the sealed area, frequency of sampling, likelihood
of spontaneous combustion, depth of the mine, and the patterns of
methane liberation. However, the Agency concludes that the rulemaking
record does not support a requirement of a risk analysis in lieu of
monitoring. Monitoring of the sealed atmosphere in areas where seals
less than 120 psi are used, and until the design strength is reached
for seals of 120 psi or greater, provides optimum safety for miners
because of the unforeseen changes that can occur within the sealed
area.
Final Sec. 75.336(a)(3) requires mine operators with an approved
ventilation plan addressing spontaneous combustion under existing Sec.
75.334(f) to sample the sealed area as specified in the approved
ventilation plan. Section 75.334(f) addresses mines with a demonstrated
history of spontaneous combustion and those located in coal seams
determined to be susceptible to spontaneous combustion. It requires
that the approved mine ventilation plan for these mines specify the
measures that will be used to detect methane, carbon monoxide, and
oxygen concentrations during and after pillar recovery, and in worked-
out areas where no pillars have been recovered; the actions that will
be taken to protect miners from the hazards of spontaneous combustion;
and the methods that will be used to control spontaneous combustion,
accumulations of methane-air mixtures, other gases, dusts, and fumes in
the worked-out area. Sampling and maintaining an inert atmosphere are
critical in sealed areas in coal mines that are subject to spontaneous
combustion of the coal seam due to this inherent ignition source.
Several commenters stated that MSHA should continue to require mine
operators to control spontaneous combustion in sealed areas through
compliance with Sec. 75.334(f). These commenters stated that the
sampling requirements of a spontaneous combustion plan should be more
comprehensive than the requirements of Sec. 75.336 to safely manage
the combustion potential. MSHA allows the spontaneous combustion
monitoring requirements in the approved ventilation plan to be used in
lieu of the monitoring requirements of this section which is more
protective for miners.
Final Sec. 75.336(a)(4), derived from ETS Sec. 75.335(b)(5)(vi),
allows the District Manager to approve the use of a continuous
monitoring system in lieu of the monitoring provisions in this section.
A continuous monitoring system may include bundles of sampling tubes
that sample a frequency of every few hours and monitor at numerous
sampling locations in the sealed area. MSHA standards addressing
atmospheric monitoring systems are in existing Sec. 75.351 and are
applicable to belt air courses, primary escapeways, return air splits,
and electrical installations. These standards do not address monitoring
in sealed areas. The final rule broadens the scope and applicability of
the ETS requirement in that it addresses continuous monitoring systems
rather than atmospheric monitoring systems. Since promulgation of the
ETS, MSHA does not believe that all of the provisions of Sec. 75.351,
atmospheric monitoring systems, are applicable to monitoring sealed
atmospheres.
One commenter stated that MSHA did not adequately address
continuous gas monitoring systems in the ETS. The final rule allows for
use of these monitoring systems. Several commenters expressed that
current atmospheric monitoring sensors could not be used in sealed
areas due to calibration and maintenance requirements. The final rule
deletes
[[Page 21195]]
reference to atmospheric monitoring systems.
Mine operators using continuous monitoring systems to monitor
sealed atmospheres must submit a revised ventilation plan to the
District Manager. The District Manager will review the revised plan to
assure that the continuous monitoring system will perform effectively.
In making a decision to approve this system, MSHA expects the mine
operator to address calibration, recordkeeping, oversight of the
continuous monitoring system, maintenance features of the monitoring
system and sampling locations.
2. Section 75.336(b)
Final Sec. Sec. 75.336(b)(1) and 75.336(b)(2) address inert
atmospheres in sealed areas. Section 75.336(b)(1), unchanged from ETS
Sec. 75.335(b)(3), defines an inert atmosphere as one in which the
oxygen concentration is less than 10.0 percent; the methane
concentration is less than 3.0 percent; or the methane concentration is
greater than 20.0 percent. MSHA has included a margin of safety in the
definition of an inert atmosphere so that mine operators can address
potential explosion hazards before having to withdraw miners. As the
Agency stated in the ETS, the explosive range of methane is 5 to 15
percent when the oxygen level is 12 percent or more (2007 NIOSH Draft
Report) which are the traditional values used in the coal mining
industry. According to the 2007 NIOSH Draft Report, methane is
explosive in air when the concentration ranges from 5 percent to 15
percent by volume. As in the ETS, to allow for the inaccuracy of
methane and oxygen detection equipment and potential contamination of
samples, oxygen less than 10.0 percent, methane concentration less than
3.0 percent and methane concentration greater than 20.0 percent are
used to determine an inert atmosphere.
For atmospheres behind seals with design strengths less than 120-
psi, final Sec. 75.336(b)(2) requires the mine operator to take
immediate action to restore the sealed atmosphere to an inert
condition. Mine operators also must sample sealed atmospheres at least
every 24 hours. In addition, MSHA requires withdrawal of miners when
methane is between 4.5 and 17 percent and oxygen is 10 percent or
greater.
Some commenters stated that until seals ``cure'' all sealed
atmospheres must be inert, including seals of 120 psi or greater, or
miners must be withdrawn from the mine. A critical time period for
seals is immediately after construction prior to seals reaching their
design strength. Miners must be protected from the hazard of an
explosive atmosphere behind seals prior to seals reaching their design
strength. Under the final rule, hazardous conditions are controlled by
frequently monitoring and maintaining an inert atmosphere or
withdrawing miners from the mine. Under MSHA's final rule, mine
operators must monitor and maintain an inert atmosphere behind all
newly-constructed seals. After 120-psi seals or greater reach their
design strength, they are not required to be monitored under Sec.
75.336. MSHA noted in the ETS that its accident history covering mines
in the United States does not include documentation of an explosion in
an underground mine that has generated an overpressure greater than 120
psi. One commenter addressing the final draft U.S. Army Corps of
Engineers report stated that the chance of having a methane gas
detonation in a coal mine is almost zero and further stated that with
using actual gob compositions the constant volume explosion loads were
found to not exceed 100 psi. Based on the Agency's experience under the
ETS and other record evidence, the final rule does not require seals
with a design strength of 120 psi or greater to be monitored after they
reach their design strength.
Several commenters stated that MSHA's definition of an inert
atmosphere in the ETS was overly conservative and recommended the
generally accepted definition of a non-explosive atmosphere of oxygen
less than 12.0 percent, and methane less than 5.0 percent or greater
than 15.0 percent. A commenter suggested an expanded explosion risk
buffer zone based on a Queensland, Australia underground coal mining
standard. Commenters also stated that MSHA should take a tiered
approach to address varying levels of methane and oxygen in the sealed
area. Some of these commenters used the term ``explosive buffer zone''
when addressing broader gas concentrations to incorporate a margin of
safety into the definition of inert and protocol requirements in ETS
Sec. Sec. 75.335(b)(4) and 75.335(b)(5). The ETS required an action
plan for which mine operators were required to address hazards
presented and actions to be taken when gas samples indicated that
oxygen was 10.0 percent or greater and methane concentrations were 3.0
percent or greater but less than 4.5 percent; 4.5 percent or greater
but less than 17.0 percent; and 17.0 percent to 20.0 percent. Several
commenters said that no buffer zones are necessary if a gas
chromatograph is used to analyze the samples. MSHA believes that
chromatographic analyses are more accurate than handheld instruments.
MSHA also believes that handheld detectors can be an adequate sampling
method to determine the methane and oxygen concentration at a sample
location. The definition of an inert atmosphere in the final rule
includes a margin of safety to account for sampling less than the
entire sealed area and time-related changes in the sealed atmosphere.
A number of commenters said that explosive atmospheres that
periodically develop when the barometric pressure is rising or the
seals are ingassing are not hazardous. The effects of ingassing depend
on several factors including the duration and magnitude of the pressure
differential across seals, leakage rates, and the typical methane
concentration for the sealed area. Therefore, MSHA believes that
hazards may exist when the seals are ingassing and the final rule is
structured to address such hazards.
Commenters objected to the ETS requirement for a 14-day baseline
sampling period or questioned its benefit. MSHA considered these
comments, but the final rule retains a 14-day initial sampling
requirement for seals less than 120 psi constructed after April 18,
2008. MSHA believes that monitoring of the sealed area during the
initial 14-day period provides optimum safety for miners because of the
unforeseen changes that can occur within the sealed area. For newly
constructed seals, the final rule is structured so that mine operators
can establish the appropriate number of sampling locations. Several
commenters expressed concern with the alternative ventilation plan
requirements for seals that only ingas or rarely outgas. MSHA has
reexamined this issue and believes that monitoring and maintaining an
inert atmosphere is protective only when the sealed area is inert at
all times. The final rule requires mine operators to establish and
maintain an inert atmosphere behind seals less than 120 psi.
Some other commenters stated that all sealed atmospheres must be
monitored and maintained inert. Another commenter said monitoring is
not the answer and that MSHA must require stronger seals. The final
rule is structured so that the mine operator can address unique
characteristics of sealed areas through either monitoring and
maintaining an inert atmosphere or using seals designed to address the
potential overpressures which may develop in the sealed area.
Another commenter stated that MSHA should require gas
concentrations in the sealed area to be maintained sufficiently
[[Page 21196]]
outside the explosive range to prevent any excursions into the
explosive zone during normal changes in barometric pressure. Finally, a
commenter suggested that one way to reduce the possibility that a
detonation may occur in the sealed area is to keep the methane air
behind the seal far from the explosive range so that changes in
pressure conditions due to foreseeable events are not possible. This
commenter also stated that methane concentration greater than 50
percent could assure that the methane range in the sealed area will not
fall within the 5 to 15 percent explosive range. In addition, this
commenter stated that the ETS required more frequent monitoring for
specified ranges of gases, but the provision does not provide a margin
of safety that would prevent swings into the explosive range for
foreseeable events such as weather, will not prevent detonations, and
sampling, regardless of the technique, will not confirm an inert status
of the sealed area.
The Agency's definition of an inert atmosphere incorporates a
margin of safety which accounts for sampling less than the entire
sealed area and time-related changes in the sealed atmosphere. MSHA
believes that the increased sampling frequencies required by the final
rule along with the definition of inert and the requirements for
withdrawal of miners will provide appropriate and necessary protection
of miners.
3. Section 75.336(c)
Final Sec. 75.336(c) revises and clarifies ETS Sec. Sec.
75.335(b)(4) and (b)(5) and addresses requirements for potentially
explosive atmospheres in sealed areas with less than 120-psi seals.
Final Sec. 75.336(c) requires that when a sample is taken from the
sealed atmosphere with seals of less than 120 psi and the sample
indicates that the oxygen concentration is 10 percent or greater and
methane is between 4.5 percent and 17 percent, the mine operator must
immediately take an additional sample and then immediately notify MSHA.
In addition, final Sec. 75.336(c) requires that when the additional
sample indicates that the oxygen concentration is 10 percent or greater
and methane is between 4.5 percent and 17 percent, persons must be
withdrawn from the affected area which is the entire mine or other
affected area identified by the operator and approved by the District
Manager in the ventilation plan, except those persons referred to in
Sec. 104(c) of the Act. Under this final rule, the operator may
identify areas in the ventilation plan to be approved by the District
Manager where persons may be exempted from withdrawal. The operator's
request must address the following factors regarding the location of
seals in relation to: (1) Areas where persons work and travel in the
mine; (2) escapeways and potential for damage to the escapeways; and
(3) ventilation systems and controls in areas where persons work or
travel and where ventilation is used for escapeways. The District
Manager, in making a determination concerning the area where persons
may be exempted from withdrawal, would take these factors into
consideration. The operator's request shall also address the gas
concentration of other sampling locations in the sealed area and other
required information.
Final Sec. 75.336(c) clarifies when miners may reenter the mine
and requires the mine operator to have an approved and revised
ventilation plan specifying the actions to be taken by the mine
operator to protect miners.
MSHA requested comments on the ETS action plan approach to
potentially explosive sealed atmospheres and whether that approach
provides adequate protection for miners. Several commenters stated that
persons should not be withdrawn merely due to explosive samples in the
sealed area and that other factors such as the size of the sealed area,
roof and weather conditions, or the volume of non-inert atmosphere
should be considered. Several commenters wanted MSHA to consider the
possibility of defining safety zones around seals. Other commenters
said that miners should unconditionally be evacuated from the mine when
any sealed atmosphere is in the explosive range. Several commenters
questioned whether an action plan could provide protection to miners
which would be equivalent to withdrawal. One commenter suggested that
rather than withdrawing miners, a ``safety zone,'' or a specific
distance, should be established around seals with explosive
atmospheres. A commenter stated that keeping miners underground with a
sealed atmosphere within the explosive range is an unacceptable risk
due to the enormous potential for a catastrophe if a seal fails.
Some action plans approved under the ETS require the withdrawal of
miners from the entire mine. MSHA now believes that some large mines
with multiple fans, multiple shafts, multiple portals, or multiple
escapeways may not require evacuation of the entire mine to protect
miners from the hazards presented by an explosion in a sealed area.
Accordingly, this final rule allows an operator to identify areas in
the ventilation plan to be approved by the District Manager where
persons may be exempted from withdrawal. The operator's request must
address the factors in this provision of the final rule. For example,
in a large mine, the District Manager may approve an area where persons
may be exempted from withdrawal if: (1) The area where persons work or
travel is remote from the sealed area; (2) the area is on separate air
splits that would not be contaminated from the gaseous products of an
explosion; and (3) those areas are served by escapeways that would not
be impacted by an explosion.
One commenter said that MSHA district offices do not have the
resources to properly evaluate proposed action plans required by the
ETS and the rule should provide specificity about the actions required
to be taken by mine operators. Action plans are not required in the
final rule. MSHA has replaced action plans with specific actions to be
taken under certain circumstances.
Several commenters said that withdrawal should only be required
when oxygen levels in the sealed area exceeded 12 percent because this
is the minimum oxygen level that will sustain an explosion at normal
atmospheric pressure. Another commenter said that introduction of
oxygen caused the formation of an explosive atmosphere. Other
commenters said that the explosive gas range is too broad. Another
commenter said the Queensland Australia regulation specifies, for
continuous monitoring, the maximum oxygen concentration should be 8
percent and the methane concentration should be less than 2.5 percent
or greater than 22 percent. Several commenters said that withdrawal
should only be required when the atmosphere in sealed area is in the
explosive range of methane which they defined as 5 percent to 15
percent.
A commenter recommended using mapping software to generate isopach
maps of methane concentration throughout the sealed area in order to
determine potentially explosive zones. MSHA does not believe that
isopach mapping software, based on arbitrary mathematical
interpolations, will accurately represent the complex methane
liberation, diffusion and convection processes in the sealed area in
combination with leakage through or around seals to predict explosive
zones with any degree of reliability.
In the ETS, MSHA referenced the 2007 NIOSH Draft Report which
stated that the explosive range is 5 to 15 percent when the oxygen
level is 12 percent or more. NIOSH, in its Final Report, stated that
methane is explosive in air when the concentration ranges
[[Page 21197]]
from 5 percent to 16 percent by volume. The NIOSH Final Report stated:
``A desirable sealed area atmosphere, from a safety perspective is
fuel-rich and oxygen-low, which is * * * less than 10% oxygen.'' The
final rule continues to account for the inaccuracies of sampling and
monitoring equipment, and for potential contamination of the gas
sample. The final rule retains the methane range of 4.5 percent to 17.0
percent with oxygen 10 percent or greater for withdrawal of miners as
specified in the ETS. This range of methane concentration is slightly
broader than the explosive range specified by NIOSH (2007 NIOSH Draft
Report and ``Handbook for Methane Control in Mining,'' Information
Circular 9486, 2006 (2006 NIOSH IC 9486), and ``Flammability of
Methane, Propane, and Hydrogen Gases,'' Cashdollar (2000). The slightly
broader range of methane includes a safety measure to help assure the
mine operator has time to safely evacuate the mine. MSHA has considered
these comments and continues to accept the methane in air mixtures
provided by NIOSH as the most appropriate basis for the final rule. The
levels in the final rule are the same as those provided in the ETS.
The ETS allowed mine operators to take three samples at one hour
intervals before requiring evacuation of the mine. Several commenters
objected to this provision. A commenter suggested that three
consecutive samples be taken at 24 hour intervals to allow the sealed
area to react to changes in the barometer. MSHA believes that it is
neither appropriate nor protective of miners' safety to allow them to
remain underground two additional hours before a mine operator confirms
a hazardous sealed atmosphere. The final rule requires that a second
sample be taken immediately and that MSHA be immediately notified
regardless of the results of the second sample.
4. Section 75.336(d)
For sealed areas with a demonstrated history of carbon dioxide or
where inert gas has been injected, final Sec. 75.336(d) allows the
mine operator to use an alternative method to determine if a particular
atmosphere is inert as defined in Sec. 75.336(b)(1). This provision
also allows the mine operator to use an alternative method to determine
when to withdraw miners as provided in Sec. 75.336(c). The mine
operator shall address the specific levels of methane, carbon dioxide,
nitrogen and oxygen in the ventilation plan; the sampling methods and
equipment used; and the methods to evaluate these concentrations
underground at the seals.
Some commenters requested MSHA to consider carbon dioxide
concentrations when making a determination for inert and explosive
atmospheres, because it is slightly more effective at preventing an
explosion than nitrogen in normal air. A commenter stated that it is
unrealistic to ignore the effects of carbon dioxide on methane
explosibility and that MSHA must let mine operators use both the Coward
flammability triangle and Zabetakis nose curve to assess whether a
sealed atmosphere is explosive. Commenters also requested that MSHA
consider excess nitrogen concentrations when determining the sealed
atmosphere.
A methane explosion requires the presence of sufficient amounts of
methane and oxygen. The presence of carbon dioxide and excess nitrogen
affects the concentrations of oxygen and methane needed for an
explosion to occur. The two most common gases used for purposes of
maintaining a sealed area inert are nitrogen and carbon dioxide. Both
gases may be obtained as cryogenic liquids transported to the mine site
on tanker trucks. Nitrogen may also be extracted from compressed air
using filter technology and carbon dioxide may be produced as the
exhaust gas from combustion processes (Tomlinson boiler, diesel engine
or jet engine). Both the ETS and final rule implicitly consider
nitrogen as an inert gas. Fresh air contains 78% nitrogen and nitrogen
is typically the most prevalent gas in sealed atmospheres. If
additional nitrogen is injected in a sealed atmosphere, it helps move
the gas mixture toward an inert status merely by diluting and rendering
harmless the methane and oxygen levels. Carbon dioxide is slightly more
effective at producing an inert atmosphere than nitrogen.
This final rule allows mine operators to use carbon dioxide and
nitrogen levels to determine how to manage the sealed atmosphere. If
the mine operator chooses an alternative method to determine if the
sealed atmosphere is inert, the operator must specify the types of
instruments that will be used to measure the gas levels and how these
more complicated evaluations will be performed at the seal. Because of
the critical nature of these measurements and determinations, the use
of gas chromatographs and computers located on the surface is not
practical except where continuous monitoring systems are used. This
surface analytical equipment cannot be used since this final rule
requires that a second sample be taken and analyzed immediately after
any near explosive gas concentrations are identified.
Although the Zabetakis nose curve or the Coward flammability
triangle is designed to show whether a methane mixture is explosive
after inert gas is added, the nose curve or flammability triangle is
not intended for the purpose of establishing an inert atmosphere under
this final rule or the explosibility range contained in the final rule.
The concentration of gases for methane in the nose curve and
flammability triangle ranges from approximately 5% to 15%. The nose
curve and flammability triangle were not designed to account for the
methane ranges specified in the final rule of 4.5% to 17% where a
safety factor is used. In addition, the use of the R-Ratio, or ratio of
methane to total combustibles, to compensate for the safety factor is
not appropriate. The alternative gas concentrations of methane, carbon
dioxide, nitrogen and oxygen must be based on sound scientific
principles. For example, operators may consider the Bureau of Mines
Bulletin 503 (Coward, H.F. and G.W. Jones, ``Limits of Flammability of
Gases and Vapors,'' Bulletin 503, U.S. Dept. of the Interior, Bureau of
Mines, 1952). The alternative gas concentrations must provide the same
levels of protection to the miners as the gas concentrations specified
in Sec. 75.336(b) and (c) of this final rule.
MSHA intends that samples of gas concentrations be analyzed
promptly. At present, handheld detectors are available to measure
carbon dioxide, methane and oxygen. The operator shall address several
related issues in the ventilation plan including handheld equipment and
methods to take these measurements underground and methods to make the
calculations necessary to evaluate the gas concentrations at the seal.
The operator should also include methods to ensure the reliability of
the sampling equipment, the training of the certified persons who must
take these samples and perform these calculations, a system to validate
these determinations and the expanded recordkeeping requirements
(additional gas concentrations).
5. Section 75.336(e)
Final Sec. 75.336(e), like ETS Sec. 75.335(b)(6) and (b)(7),
requires that the mine operator promptly record sampling results and
that these records be maintained at the mine for at least one year.
MSHA received no comments on this provision.
[[Page 21198]]
C. Section 75.337 Construction and repair of seals
Final Sec. 75.337 is derived from the ETS requirements on
construction and repair of seals.
1. Section 75.337(a)
Final Sec. 75.337(a) clarifies the ETS and requires mine operators
to maintain and repair seals to protect miners from hazards of sealed
areas. MSHA is including this provision in this final rule in response
to comments concerning seal repairs. This final rule addresses non-
structural repairs only. Non-structural repairs are those that are
related to general maintenance and include: excessive air leakage
through and around seals; repair of minor cracks; spalling of seal
coating; water drainage systems; and sampling pipes. One commenter
expressed concern that seals may become inaccessible, deteriorate,
weaken, and be impossible to repair. This section does not apply to
seals that require structural repairs. MSHA will continue to require
that seals in need of structural repairs be replaced since they would
no longer serve their necessary function. Seals, with the exception of
seals used to separate the active longwall panel from the panel
previously mined that are inby the longwall face, must be maintained
accessible or be replaced.
2. Section 75.337(b)
Final Sec. 75.337(b) renumbers Sec. 75.337(a) of the ETS, and
specifies requirements that a mine operator must follow prior to
sealing.
Under final Sec. 75.337(b)(1), mine operators must remove
insulated cables from the area to be sealed. Final Sec. 75.337(b)(1)
clarifies the ETS and requires that mine operators remove batteries and
other potential electric ignition sources from the area to be sealed.
Because an electric arc can occur if a length of insulated cable were
inductively coupled to an electromagnetic pulse such as a lightning
strike, this final rule reduces the hazard of an explosion caused by an
electric discharge.
Several commenters stated that the removal of insulated cables is
unnecessary, infeasible, unrealistic and can be unsafe. One commenter
suggested that grounding the ends of a cable may safeguard cables that
cannot be removed. Other commenters stated that as mine operators
complete mining activities in an area, they recover the more useful
cables and may only leave behind damaged or deteriorated cables.
Another commenter stated that there can be miles of cables to pumps or
electric installations that must continue to run to within days or
hours of final sealing, and that it would be impossible to remove these
cables prior to sealing. One commenter suggested that cable removal
would be unnecessary if seals are constructed to withstand explosive
forces. One commenter suggested that the final rule include a provision
for removing batteries from the area to be sealed.
To reduce the hazard of an explosion from an electric discharge,
and to assure miners' safety, MSHA believes that it is necessary to
remove cables, batteries, and other potential ignition sources prior to
sealing unless it is not safe to do so. Other potential ignition
sources include motors, transformers and electromagnetic devices.
Potential electric ignition sources that may expose miners to dangerous
conditions, such as those that are buried under a roof fall, would not
have to be removed.
Based on MSHA's knowledge and experience, if one end of an
insulated cable is grounded and one is not, a potential ignition source
remains. Also, a potential ignition source remains even if both ends of
a cable are grounded because the condition of the conductors within the
cable would not be known. Based on MSHA testing, cable cannot generally
be considered safe by grounding either one or both ends.
The final rule includes a clarifying change that if ignition
sources cannot be safely removed from the area to be sealed, seals must
be constructed to at least 120 psi. NIOSH indicated in their 2007 NIOSH
Final Seal Report that a 50 psi peak overpressure could occur in a
limited-volume, unconfined situation. Leaving a potential ignition
source, such as a cable, in the sealed area could increase the
probability that larger pockets of gas, which may be undetected through
sampling, could be ignited, resulting in an explosion. An explosion in
a larger area could result in overpressures greater than 50 psi.
Therefore, the final rule provides appropriate protection for miners if
ignition sources cannot be safely removed from the area to be sealed.
The installation of at least 120 psi seals would provide protection for
miners and prevent the explosion in the sealed area from propagating to
the active workings of the mine.
Final Sec. 75.337(b)(2), like the ETS, requires removal of
metallic objects that pass through or across seals. Screens, straps,
rails, and channels are examples of the types of metallic objects that
are required to be removed under this final rule. In addition, this
final rule does not include the exception in the ETS for metal sampling
pipes, water drainage pipes, and form ties. Removal of metallic objects
before seals are built reduces the hazard of methane explosions and
improves miner safety.
Several commenters suggested that metal sampling pipes, water
drainage pipes, and form ties need not be removed because nonmetallic
materials can be used as alternatives. MSHA agrees. Alternative
nonmetallic materials exist and can be used for gas sampling pipes,
water drainage systems, and form ties. The use of these alternative
materials will reduce methane explosion hazards and enhance miner
safety.
Several commenters stated that removal of metallic roof support is
hazardous. One commenter noted that an accident occurred during removal
of wire mesh at a seal location. Based on MSHA's experience, removal of
metallic roof support can be accomplished safely so long as appropriate
precautions are taken. Under the final rule, the best option would be
for an operator to plan the location of the seals and the roof
supports, such as cribs and non-metallic mesh, to be used in the area
to be sealed.
One commenter requested clarification of the hazards associated
with metallic roof mesh or mats that are grounded. Based on MSHA's
experience, metallic roof mesh or mats are not always adequately
grounded. In addition, metallic roof mesh or mats are potential
conductive paths into the sealed area and need to be removed.
One commenter stated that MSHA should not require removal of de-
gassing, inerting, or pre-sealing ventilation pipes that may be needed
to effectively control the gob atmosphere. Based on MSHA's experience,
these metallic objects can provide a conduit for electric current to
enter the sealed area and ignite methane/air mixtures. Removal of these
objects before seals are built reduces the hazard of methane explosions
and improves miner safety. Therefore, in response to its request for
comments in the ETS on information concerning the removal of metallic
objects, the final rule requires removal of metallic objects through or
across seals.
Final Sec. 75.337(b)(3) is new. It requires mine operators to
breach or remove all stoppings in the first crosscut inby the seals
immediately prior to sealing the area. This procedure is a recognized
common practice in the coal mining industry.
One commenter stated that monitoring could easily provide a false
sense of security. Another commenter said that sampling behind one seal
in a set would not be able to detect a pocket
[[Page 21199]]
of explosive gas that may exist. In response to commenters'' concerns,
the final rule includes the requirement to remove or breach the
stopping in the first connecting crosscuts inby seal locations. Under
MSHA's experience, breaching or removing stoppings allows the same
atmosphere to exist immediately inby each seal as exists throughout the
sealed area. Ventilation stoppings in the first connecting crosscut
inby the seal locations are used to maintain ventilation, through the
area to be sealed, during seal construction. These stoppings should not
be breached or removed until immediately prior to installing the final
seal. The timing of the breaching or removing of stoppings is critical
and should be addressed in the mine ventilation plan under Sec.
75.335(c)(3)(iv)(N).
3. Section 75.337(c)
Final Sec. 75.337(c), renumbers ETS Sec. 75.337(b), and requires
a certified person designated by the mine operator to directly
supervise seal construction and repair. Existing Sec. 75.100 defines a
certified person as one certified by the Secretary of Labor or the
State in which the coal mine is located. Following explosions at the
Sago and Darby mines in 2006, MSHA inspected seals in underground coal
mines across the country and concluded that some seals were not
correctly built. The supervision requirement will help assure that seal
construction and repair are performed correctly.
Under final Sec. 75.337(c)(1), the certified person must examine
each seal site immediately prior to construction or repair to assure
that the site is in accordance with the approved ventilation plan.
Under final Sec. 75.337(c)(2), the certified person must examine each
seal under construction or repair during each shift to assure that the
seal is being constructed or repaired in accordance with the approved
ventilation plan. Under final Sec. 75.337(c)(3), the certified person
must examine each seal upon completion of construction or repair to
assure that construction or repair is in accordance with the approved
ventilation plan.
Some commenters objected to these provisions stating that it was
unnecessary and burdensome for the certified person to supervise the
entire construction process. They stated that trained qualified persons
should be permitted to repair or construct seals in accordance with the
approved plan and that the certified person can then conduct an
examination to assure the plan was followed. Other commenters, however,
supported a requirement for a certified person to be on site during
each step of seal construction.
MSHA believes that a certified person needs to be in the vicinity
of the seal site to address problems and questions during seal
construction or repair. Under the final rule, MSHA does not intend that
a certified person continuously observe construction or repair of all
seals in a set. The certified person should be available at each seal
site during the shift to assure proper construction or repair.
Some commenters expressed concern regarding potential conflicts
created by requiring that certain tasks be performed, under the ETS, by
both professional engineers and certified persons. Based on MSHA's
experience under the ETS, the Agency has not encountered any potential
conflicts and does not believe any are likely to arise. The role of the
professional engineer to have oversight of seal installation is more
fully discussed in Sec. 75.335(c).
Final Sec. 75.337(c)(4), like the ETS, requires that the certified
person certify by initials, date, and time that the examinations were
made. MSHA did not receive any comments on this provision.
Final Sec. 75.337(c)(5), like the ETS, requires that the certified
person make a record of the examination at the completion of any shift
during which an examination was conducted, and include each deficiency
and the corrective action taken. The record must be countersigned by
the mine foreman or equivalent mine official by the end of the mine
foreman's or equivalent mine official's next regularly scheduled
working shift, and the record must be kept at the mine for one year.
This recordkeeping requirement allows MSHA and other persons to
determine that examinations have been conducted, that results are
valid, and that deficiencies in site preparation, construction and
repairs were found and corrected. In addition, the record must identify
seal completion dates.
One commenter stated that countersigning simply identifies the
person to blame in the event of an accident or seal failure. Another
commenter stated that countersigning was unnecessary. Historically, the
countersigning requirement has been an integral part of MSHA's
enforcement of coal mining standards. It is consistent with other
recordkeeping requirements in 30 CFR part 75; such as Sec. Sec. 75.360
(pre-shift examination) and 75.361 (supplemental examination), 75.362
(on-shift examination), 75.363 (hazardous conditions), and 75.364
(weekly examination). The countersignature must be made by the end of
the mine foreman's or equivalent mine official's next regularly
scheduled working shift. If the mine foreman or equivalent mine
official is absent, the person acting in that position would review and
countersign the record. Based on MSHA's experience under the ETS, this
provision assures that a mine foreman or equivalent mine official is
responsible for seal installation.
4. Section 75.337(d)
Final Sec. 75.337(d) renumbers Sec. 75.337(c) of the ETS, and
requires that upon completion of construction of each seal, a senior
mine management official, such as a mine manager or superintendent,
certify that the construction, installation, and materials used were in
accordance with the approved mine ventilation plan. It also requires
the mine operator to retain the certification for as long as the seal
is needed to serve the purpose for which it was built.
Some commenters stated that this certification was unnecessarily
duplicative of the certification required by the certified person
during construction and repair and the certification required by the
professional engineer during the plan approval process. Some commenters
stated that the certification requirement by a senior mine official is
unreasonable and redundant because the official may not have expertise
to make certification; the official may not have knowledge unless
present during construction; a professional engineer is required to
have ``oversight''; the certified person directly supervises
construction and makes a record of the exam; and the mine foreman
countersigns the certified person's record. Other commenters suggested
modification of the ETS requirement to either allow a senior mine
official to rely on reports from the professional engineer and
certified person, or to allow a senior mine management official to
countersign the official seal record book.
Based on MSHA's experience regarding methane explosions in sealed
areas and MSHA's experience regarding the same certification
requirements under the ETS, the Agency believes that some amount of
redundancy is necessary in the review of these critical seal
construction tasks; this provides an added margin of safety for miners.
Certifications by certified persons, and senior mine management
officials protect miners by helping assure that the seal is correctly
designed and constructed.
[[Page 21200]]
5. Section 75.337(e)
Final Sec. 75.337(e) renumbers Sec. 75.337(d) of the ETS, and
remains essentially unchanged. Final Sec. 75.337(e)(1) requires the
mine operator to notify the District Manager between two and fourteen
days prior to commencement of seal construction. This final rule
revises the ETS requirement to notify the MSHA local field office.
One commenter supported the notification requirement stating that
it is necessary so that MSHA can oversee seal construction. This
commenter recommended that an MSHA inspector be present at least part
of the time during seal construction.
One commenter opposed the notification requirement. This commenter
stated that it is inefficient to require contacting MSHA since an MSHA
inspector is at the mine over 150 days during the year. In the final
rule, MSHA has retained the notification requirement because the Agency
believes that it is necessary and it is also responsive to comments.
This requirement gives MSHA the opportunity to observe seal
construction and to help assure that the construction, installation and
materials were in accordance with the ventilation plan approved by
MSHA. The requirement to notify the District Manager establishes
consistency with other MSHA notification requirements. Like other
notification provisions, the District Manager either contacts the
appropriate field office or inspectors from the District Office may
make the inspection.
Final Sec. 75.337(e)(2), like the ETS, requires the mine operator
to notify the MSHA District Manager, in writing, within five days of
completion of each set of seals and provide a copy of the certification
required in Sec. 75.337(d) of this section. The purpose of this
provision is to give the District Manager notice of completed seal
construction. The period immediately following construction of the seal
is the time during which seals are achieving full strength and the
atmosphere inby the seals may be transitioning into or through a
potentially explosive methane/air mixture. During this critical time
period, the District Manager may decide to inspect the seals or sample
the sealed area.
Final Sec. 75.337(e)(3), like the ETS, requires the mine operator
to submit a copy of quality control test results for seal material
properties specified in Sec. 75.335 to the District Manager. To
clarify the performance required, the final rule includes a requirement
that the test results be submitted within 30 days of completion of the
tests. The final rule, like the ETS, requires that test results include
all tests of seal construction materials. Some commenters expressed
concern over a specified time requirement for the submission of quality
control tests results because some results are often not available for
weeks after the tests are completed. Sampling must be continued on a
24-hour basis for all seals until MSHA receives the test results and
determines that they are adequate. Based on MSHA's experience under the
ETS, MSHA believes that a 30-day period will provide sufficient time to
obtain results and assures that test results are submitted promptly.
MSHA has not experienced any problems with this timeframe under the
ETS.
6. Section 75.337(f)
Final Sec. 75.337(f) renumbers Sec. 75.335(c) of the ETS, and
like the ETS, prohibits welding, cutting, and soldering with an arc or
flame within 150 feet of a seal. This final rule revises the ETS by
allowing this work within 150 feet of a seal unless it is not safe to
do so. The operator may request that the District Manager approve a
different location in the ventilation plan. The purpose of this
provision is to protect miners from the hazards of open flames near
seals. A methane enriched atmosphere can leak through the seal,
accumulate out by the seal, and if ignited, the flame can propagate
into the sealed area causing an explosion.
The 150-foot limit in the final rule is consistent with an existing
MSHA requirement in Sec. 75.1002(a) that non-permissible equipment be
excluded within 150 feet of pillar workings or longwall faces. To
measure the 150 feet, MSHA recommends that mine operators use the
longstanding industry practice of following the shortest distance that
air can travel (tight string distance) through crosscuts, entries or
other openings (MSHA Program Policy Manual, Volume V, Subpart J
(February 2003)).
In response to MSHA's request for comments, some commenters
supported and others opposed the provision. Commenters who supported
the provision stated that the protection was necessary to prevent
another explosion like the one that occurred at the Darby Mine.
Commenters who opposed the provision stated that it was too restrictive
and unenforceable under current mining conditions. Some of these
commenters stated that the provision could significantly interrupt
mining operations where the next entry from the seal contains a pre-
existing belt, belt-drive, shop area, travelway, or track. In addition,
some commenters requested that MSHA consider that some belt drives in
underground coal mines have separate splits of large quantities of air,
and that compliance flexibility should be included in the final rule to
accommodate different mining conditions.
In response to comments and based on MSHA's experience under the
ETS, MSHA has revised the ETS. An operator may request that the
District Manager approve in the ventilation plan welding, cutting, and
soldering with an arc or flame within 150 feet of a seal. The
operator's request must address methods the mine operator will use to
continuously monitor atmospheric conditions in the sealed area during
welding or burning; the airflow conditions in and around the work area;
the rock dust and water application methods; the availability of fire
extinguishers on hand; the procedures to maintain safe conditions, and
other relevant factors. MSHA believes that welding, cutting and
soldering with an arc or flame near a sealed area may be allowed
depending upon mining conditions at the mine, and that determination
should be made by the District Manager on a case-by-case basis.
7. Section 75.337(g)
Final Sec. 75.337(g) renumbers and revises Sec. 75.335(d) of the
ETS. Final Sec. 75.337(g)(1) requires one non-metallic sampling pipe
in each seal that extends into the center of the first connecting
crosscut inby the seal. The final rule requires that if an open
crosscut does not exist, the sampling pipe shall extend into the center
of the length of the open entry inby the seal. The requirement that
only non-metallic materials be used for sampling pipes is consistent
with other provisions of this final rule that require the removal of
metallic objects through or across seals.
MSHA received many comments regarding the ETS requirements on the
locations and number of sampling pipes. Many commenters questioned the
requirement of two sampling pipes in each seal. They stated that it is
doubtful that two sampling pipes in each seal will provide much
additional information and they could result in conflicting and
confusing information. In addition, several commenters disagreed with
the need for a sampling pipe in each seal. Some commenters questioned
whether a representative sample could be obtained by using a sampling
pipe through a seal. Several commenters suggested putting a sampling
pipe at the high and low points of the seals. One commenter stated that
the location and number of
[[Page 21201]]
sampling pipes should be based on the mining conditions.
MSHA reviewed sampling data collected under the ETS 14-day baseline
requirement and other sampling data, including that associated with the
Agency's citations and withdrawal orders. Based on this review, MSHA
believes that one sampling pipe provides adequate information and that
two sampling pipes in each seal are not necessary and could result in
conflicting and confusing information. In addition, the Agency's
evaluation of its sampling data from the 15-foot pipe found significant
variation of methane concentrations at different seals in the set and
between sets of seals for the same sealed area. MSHA attributes this to
different ventilation pressures at the various seals and differences in
leakage characteristics through the ribs and strata surrounding the
seals (cracks, joints, etc), depending on the location of the seals.
MSHA believes that sampling points with a longer pipe located within
the first connecting crosscut will provide a more representative sample
of the sealed area because this atmosphere is less likely to be
affected by ingassing. In addition, this sampling location is less
susceptible to swings in oxygen levels associated with changes in
barometric pressure. Based on comments, data, and Agency experience,
MSHA has revised the ETS to remove the requirement that a sampling pipe
extend 15 feet into the sealed area.
One commenter stated that gob isolation seals are installed in
crosscuts immediately behind the longwall face and, therefore, it would
be impossible to meet the requirements to extend one tube into the
center of the first connecting crosscut inby the seal as that
intersection will no longer exist once the longwall mines pass the
crosscut where the seal is to be installed. In addition, this commenter
stated that installing sampling pipes near the intersection is not
practical as crosscut conditions often quickly deteriorate on the gob
side of the seal. Under circumstances where gob isolation seals will
have no connecting crosscut inby the seal, or under similar
circumstances, the sampling pipe must be extended to the center of the
expected open space to obtain a sample that is representative of the
gas in the sealed area. In addition, under circumstances where crosscut
conditions may deteriorate, sampling pipes should be located so that
they are subjected to the least amount of deterioration. Even if some
pipes deteriorate, it is unlikely that all pipes will deteriorate at
every sampling location. In addition, under this final rule, the
District Manager may require additional sampling locations in the
ventilation plan under Sec. 75.336.
Final Sec. 75.337(g)(2) retains the ETS requirement that each
sampling pipe be equipped with a shut-off valve and appropriate
fittings for taking gas samples. MSHA received no comments on this
provision.
Final Sec. 75.337(g)(3) is new. It requires the sampling pipes to
be labeled to indicate the location of the sampling points when more
than one sampling pipe is required under Sec. 75.337(g)(4).
Final Sec. 75.337(g)(4) is derived from and is consistent with
existing MSHA enforcement policy under the ETS. If a new seal is
constructed to replace or reinforce an existing seal with a sampling
pipe, final Sec. 75.337(g)(4) requires the sampling pipe in the
existing seal to be extended through the new seal. It also requires
that an additional sampling pipe be installed through each new seal to
sample the area between seals, as specified in the approved ventilation
plan. Final Sec. 75.337(g)(4) is consistent with existing MSHA policy
that addresses requirements for placement of the sampling pipe when a
new seal is constructed outby an existing seal to replace or reinforce
an existing seal.
Final Sec. 75.337(g)(4) was added to clarify requirements gained
as a result of MSHA's experience under the ETS concerning construction
of new seals immediately outby existing seals that had been either
damaged, or had had significant structural defects. In addition, some
operators of mines with potentially explosive atmospheres decided to
construct new 120-psi seals outby existing seals under the ETS. Under
these circumstances, MSHA found that if a new seal is constructed as an
extension or reinforcement of an existing seal, there may be no
additional sealed area to sample. In addition, most existing seals have
only one sampling pipe per set of seals and some sets of seals that
predate MSHA's 1992 ventilation standards may have no sampling pipes.
If the new seals are close to the existing seals, an explosion in
the area inby the old seals could damage the new seals. By maintaining
the area inert between the new seals and the old seals, the possibility
of an explosion between the seals effectively is eliminated. MSHA
considered requiring the mine operator to drill holes through existing
seals to install sampling pipes. MSHA rejected this approach due to the
possibility of sparking or frictional ignition associated with
drilling.
The final rule requires that sampling pipes in existing seals be
extended through the new seals to permit the sampling of the atmosphere
inby the existing seals. If there is a space between the new seals and
the existing seals, this area will need to be sampled and maintained
inert and will require a sample pipe through each new seal. If the
space between the seals does not include a connecting crosscut, the new
sampling pipe must be extended to the center of the open space.
8. Section 75.337(h)
Final Sec. 75.337(h) renumbers and revises Sec. 75.335(e) of the
ETS. It requires that for each set of seals, the seal at the lowest
elevation shall have a corrosion resistant, non-metallic water drainage
system. In addition, seals must not impound water or slurry, and water
or slurry cannot be allowed to accumulate within the sealed area to any
depth that can adversely affect a seal.
This final rule revises the ETS requirement by allowing only non-
metallic materials to be used for a drainage system. This requirement
is consistent with other provisions of this final rule regarding the
removal of metallic objects through or across seals. MSHA experience
shows that alternatives to metallic materials are readily available for
use in drainage systems.
In response to MSHA's request, several commenters stated that the
ETS requirement that a seal not impound water is vague, that it is
impossible to guarantee that there will be no water at a seal, and that
there will always be some minimal amount of standing water in some
mines. Seals should not be designed to impound water other than to a
minimal depth, such as the height of the water trap. Based on MSHA's
experience, drainage systems can be designed to prevent the
accumulation and impoundment of mine water inby the seals. The actual
size and number of pipes used in a drainage system should be based on
the anticipated maximum flow rate at the seal location. In addition to
being corrosion resistant and made of non-metallic material, drainage
pipes must have strength properties consistent with the design strength
of the seal, and the drainage system must have blast resistance
equivalent to that of the seal. If the seal design does not allow any
impoundment of water, the drainage system design could incorporate a
water diversion or pumping system. For example, a low weir or catchment
could be constructed across the entry inby the seal to trap sediment
and debris that may impede drainage and prevent water from adversely
affecting the seal. These provisions addressing water drainage systems
and impoundment of water or
[[Page 21202]]
slurry accommodate varied mining conditions and assure safe and
effective workplaces for miners.
D. Section 75.338 Training
Final Sec. 75.338 addresses training for sampling and seal
construction. This final rule consolidates the training requirements of
ETS Sec. Sec. 75.335(b)(2) and 75.337(e) into this new section. The
final rule changes the retention period for training certifications
from one year to two years from the date of training. This change is
made to be consistent with existing MSHA training standards at part 48.
It provides that mine operators maintain training records under the
final rule for the same period as existing training records. Consistent
with the burden cost in MSHA's information collection package for part
48, under OMB Control Number 1219-0009, the Agency determined that
increasing the retention period from one year to two would not affect
operator costs.
1. Section 75.338(a)
Final Sec. 75.338(a), like the ETS, requires that certified
persons conducting sampling be trained in the use of appropriate
sampling equipment, procedures, location of sampling points, frequency
of sampling, size and condition of the sealed area, and the use of
continuous monitoring systems, if applicable, before they conduct
sampling, and annually thereafter. The final rule also requires the
mine operator to certify the date of training and retain each
certification for two years, instead of one year under the ETS. This
provision is similar to other certification requirements in 30 CFR part
75.
2. Section 75.338(b)
Final Sec. 75.338(b), like the ETS, requires the mine operator to
provide training to miners constructing or repairing seals, designated
certified persons, and designated senior mine management officials.
This training must be conducted prior to constructing or repairing a
seal and annually thereafter. The final rule also requires the mine
operator to certify the date of training provided each miner, certified
person, and senior mine management official, and retain each
certification for two years.
One commenter stated that the record showing certification of
training for miners doing the construction of seals is required to be
kept for only one year. If there is a seal failure outside of that time
period, those records are no longer available during the investigation
process. The commenter recommended that the certification be kept for
as long as the seal is satisfying the purpose for which it was built.
This final rule revises the ETS by requiring operators to retain
training certifications for two years from the date of training. This
change is consistent with existing Sec. 48.9 (records of training)
which requires training certificates be kept at the mine site for two
years. Training certifications need not be kept longer than two years
because the final rule requires annual training for miners constructing
or repairing seals. Annual training assures that miners are capable of
repairing seals when necessary and therefore, the training
certification would be up-to-date.
Several commenters requested clarification as to whether the
training provisions are included in part 48 training. Training required
by the final rule should not be included in part 48 training, although
the mine operator may choose to conduct the training at the same time.
However, even though the ventilation plan review is required as part of
the eight-hour annual refresher training, additional time must be
allotted since the training is required by this section, not part 48.
The final rule does not require a minimum amount of time for
training. MSHA expects mine operators to determine the time necessary
for this training based on the complexity of the seal design in the
ventilation plan, construction or repair procedures, materials used,
and knowledge and skill levels of persons receiving training. In
addition, changes in the approved seal design or approved ventilation
plan will necessitate that persons be retrained.
E. Section 75.339 Seals records
Final Sec. 75.339, like ETS Sec. 75.338, addresses seals records.
1. Section 75.339(a)
Final Sec. 75.339(a) lists the records a mine operator is required
to maintain and the retention time for those records.
2. Section 75.339(b)
Final Sec. 75.339(b), like the ETS, requires that records be
retained at a surface location at the mine in a secure book that is not
susceptible to alteration. The final rule allows records to be retained
electronically in a computer system that is secure and not susceptible
to alteration, if the mine operator can immediately access the record
from the mine site.
One commenter stated that after seal construction is completed and
quality control test results have been provided to MSHA, the operator
should be permitted to retain seal construction certification records
at a central location. Because electronic storage of records is a
practical and reliable method of records storage, the final rule allows
records to be stored electronically, provided that the records are
secure and not susceptible to alteration.
3. Section 75.339(c)
Final Sec. 75.339(c) of the final rule remains unchanged from the
ETS. It requires that, upon request from an authorized representative
of the Secretary of Labor or Secretary of Health and Human Services, or
from the authorized representative of miners, mine operators must
promptly provide access to any record listed in the table in this
section.
4. Section 75.339(d)
Final Sec. 75.339(d), like the ETS, requires that whenever an
operator ceases to do business, that operator must transfer all records
required to be maintained by this part, or a copy thereof, to any
successor operator who must maintain them for the required period. In
addition, in response to comments, this final rule revises the ETS to
require an operator who transfers control of the mine to another entity
to transfer all records to that successor entity. Having access to
records will allow MSHA and the new mine operator to determine if seals
were designed, constructed, and repaired as approved and maintained to
assure their reliability.
F. Section 75.371 Conforming Changes to Other Sections of Part 75
Final Sec. 75.371(ff) requires the mine operator to provide in the
ventilation plan the information provided in the sampling requirements
in Sec. 75.336 and the seal installation requirements in Sec. 75.335.
The sampling requirements in ETS Sec. 75.335(b) are revised and moved
to final Sec. 75.336. The installation requirements provided by ETS
Sec. 75.336(b)(3) are revised and moved to final Sec. 75.335.
Therefore, this provision is revised to conform to the new section
numbers.
IV. Executive Order 12866
Executive Order (E.O.) 12866, as amended by E.O.13258 (Amending
Executive Order 12866 on Regulatory Planning and Review), requires that
regulatory agencies assess both the costs and benefits of regulations.
To comply with E.O.12866, MSHA has prepared a Regulatory Economic
Analysis (REA) for the final rule. The REA contains supporting data and
explanation for the summary materials presented in this
[[Page 21203]]
preamble, including the covered mining industry, costs and benefits,
feasibility, small business impacts, and paperwork. The REA is located
on MSHA's Web site at http://www.msha.gov/REGSINFO.HTM. A copy of the
REA can be obtained from MSHA's Office of Standards, Regulations, and
Variances at the address in the ADDRESSES section of this preamble.
Executive Order 12866 requires that regulatory agencies assess both
the costs and benefits of significant regulatory actions. Under the
Executive Order, a ``significant regulatory action'' is one meeting any
of a number of specified conditions, including the following: Having an
annual effect on the economy of $100 million or more, creating a
serious inconsistency or interfering with an action of another,
materially altering the budgetary impact of entitlements or the rights
of entitlement recipients, or raising novel legal or policy issues.
Based on the REA, MSHA has determined that the final rule does not have
an annual effect of $100 million or more on the economy. Therefore, it
is not an economically ``significant regulatory action'' under section
3(f) of E.O. 12866. MSHA, however, has determined that the final rule
is a ``significant action'' under Executive Order 12866 because it
raises novel legal or policy issues.
A. Mine Sector Affected
The final rule applies to all underground coal mines in the United
States. Based on MSHA data as of February 5, 2008, there were 624
underground coal mines, employing 42,207 miners, operating in the U.S.
in 2007. Based on an MSHA survey conducted in November 2006, 372
underground coal mines have seals. In 2007, these mines employed 32,412
miners, of which 28,009 worked underground.
B. Benefits
To provide a quantitative estimate of the benefits of this final
rule, MSHA analyzed the explosions in sealed areas that have taken
place since 1993 including the two accidents in 2006 where the seals
failed and fatalities occurred. At the Sago Mine, 12 miners died, and
at the Darby Mine, 5 miners died. If this final rule had been in
effect, these lives might not have been lost.
For purposes of estimating benefits for this final rule, MSHA
attributes the potential saving of the 5 miners' lives from the Darby
Mine accident to this final rule. MSHA also attributes the potential
saving of half of the miners' lives from the Sago Mine accident. (MSHA
attributes the remaining miners' lives from the Sago Mine accident to
MSHA's 2006 emergency mine evacuation rule.) The total potential saving
is 11 lives attributed to this final rule.
One commenter stated that under the ETS, MSHA should not have
included as a benefit potential lives saved from the Sago and Darby
Mine accidents. This commenter stated that the design of the seals used
at both the Sago and Darby Mines was not established as the cause of
the deaths, that MSHA's accident reports focus on construction
deficiencies of seals at both mines, and that the Darby Mine explosion
resulted from miners attempting to cut a metal strap on the inby and
outby side of a previously constructed seal. Based on MSHA's experience
under the ETS, MSHA believes that the lives lost at the Sago and Darby
Mine accidents might have been saved had this final rule been in
effect. This final rule, like the ETS, addresses the design,
construction, and maintenance of seals, and training of persons
involved in seal construction and repair. The final rule requires
insulated cables be removed from the area to be sealed, unless it is
not safe to do so. In addition, this final rule does not permit
welding, cutting, and soldering with an arc or flame within 150 feet of
a seal unless such work is approved by the District Manager in the
ventilation plan.
MSHA has data on explosions that occurred in sealed areas. From
1993 through 2006, there were 13 explosions in sealed areas. Of the 13
explosions, 11 caused seal damage and had the potential to cause
fatalities or injuries, and two caused fatalities or injuries. If the
explosions followed approximately the same distribution as they did
since 1993, MSHA estimates that this final rule would save
approximately one life per year.
Based on the Agency's knowledge and experience, MSHA determined
that the risk from explosions in sealed areas was increasing from 1993
through 2006 because the number of seals being installed was increasing
during that period. After adjusting this estimate to account for the
increased risk during the period, this final rule will save
approximately 2 lives per year. The estimate that the final rule will
save approximately 2 lives per year is based on an increased risk of an
explosion during 1993-2006 because the number of seals in mines
increased and the number of mines with seals increased. This is MSHA's
best estimate of the number of lives saved per year due to the final
rule.
MSHA also developed a higher risk estimate based on the
distribution of miners at risk and the characteristics of the
explosions. If an explosion with the characteristics of the explosions
at Sago or Darby Mines were to occur at a large mine, many lives
potentially could be lost. Assuming that the risk of fatality from an
explosion in a sealed area does not vary with the size of the mine, and
that the number of potential fatalities is proportional to the number
of miners working underground, MSHA estimates that approximately 6
lives will be saved per year under this final rule.
MSHA also calculated the cumulative risk over a 45-year working
life of a miner. If, under MSHA's best estimate, this final rule saves
approximately 2 lives per year, the risk of fatality from an explosion
in a sealed area is approximately 3 per 1,000 miners over a 45-year
working lifetime. If the final rule saves 6 lives per year under MSHA's
higher estimate, the reduction in the lifetime risk of a fatality from
an explosion in a sealed area is approximately 9 per 1,000 miners over
a 45-year working lifetime.
Under this final rule, an explosion is less likely to occur where
the atmosphere behind seals is monitored and maintained inert. This
final rule also requires stronger seals to better withstand explosions.
The stronger seals will reduce miner injuries and fatalities should an
explosion occur.
C. Compliance Costs
MSHA estimates that the final rule will result in total yearly
costs for underground coal mine operators of approximately $45.4
million. Total first year costs are estimated to be approximately $46.4
million. Disaggregated by mine size for mines that use seals, yearly
costs are $2.8 million for the 83 mine operators with fewer than 20
employees; $37.8 million for the 279 mine operators with 20-500
employees; and $4.8 million for the 10 mine operators with more than
500 employees. Most of the compliance costs occur in the mine size
category with 20-500 employees because 75 percent of the mines that use
seals are in this category.
V. Feasibility
MSHA has concluded that the requirements of the final rule are
technologically and economically feasible. For atmospheres behind seals
where the atmosphere will not inert naturally, operators may choose any
of the following alternatives for inerting the atmosphere: (1)
Injecting inert gas; or (2) pressure balance of the ventilation system;
or (3) injecting material into the strata surrounding the seals to
reduce leakage. Other mines may choose to
[[Page 21204]]
construct new seals that are 120 psi or greater in front of all
existing seals in the sealed area.
A. Technological Feasibility
MSHA concludes that the final rule is technologically feasible.
This conclusion is based on the requirements of the final rule for
training, sampling, construction and repair. Compliance with these
requirements is technologically feasible because the materials,
equipment, and methods for implementing these requirements currently
exist. In addition, this feasibility determination is supported by
MSHA's approval of several seal designs at overpressures of 50 psi and
120 psi.
B. Economic Feasibility
The yearly compliance cost of the final rule is $45.4 million,
which is 0.3 percent of all revenue for all underground coal mines.
MSHA concludes that the final rule is economically feasible because the
total yearly compliance cost is well below one percent of the estimated
annual revenue for all underground coal mines.
VI. Regulatory Flexibility Act and Small Business Regulatory
Enforcement Fairness Act
Pursuant to the Regulatory Flexibility Act (RFA) of 1980, as
amended by the Small Business Regulatory Enforcement Fairness Act
(SBREFA), MSHA analyzed the impact of the final rule on small
businesses. Based on that analysis, MSHA notified the Chief Counsel for
Advocacy, Small Business Administration, and certified under the
Regulatory Flexibility Act at 5 U.S.C. 605(b) that the final rule does
not have a significant economic impact on a substantial number of small
entities. The factual basis for this certification is in Chapter V of
the REA, and is summarized below.
A. Definition of a Small Mine
Under the RFA, in analyzing the impact of the final rule on small
entities, MSHA must either use the Small Business Administration (SBA)
definition for a small entity or, after consultation with the SBA
Office of Advocacy, establish an alternative definition for the mining
industry by publishing that definition in the Federal Register for
notice and comment. MSHA uses the SBA definition. The SBA defines a
small entity in the mining industry as an establishment with 500 or
fewer employees. MSHA concludes that it can certify that the final rule
does not have a significant economic impact on a substantial number of
small entities, those mines with 500 or fewer employees.
B. Factual Basis for Certification
MSHA initially evaluates the impacts on ``small entities'' by
comparing the estimated compliance cost of a rule for small entities in
the sector affected by the rule to the estimated revenue for the
affected sector. When the estimated compliance cost is less than one
percent of the estimated revenue, the Agency concludes that the rule
does not have a significant economic impact on a substantial number of
small entities. When the estimated compliance costs exceeds one percent
of revenue, MSHA determines whether a further analysis is required.
For underground coal mines, the estimated 2007 production was
277,830,429 tons for mines that had 500 or fewer employees. Using a
2007 price of underground coal of $40.37 per ton and total 2007
underground coal production in tons, underground coal revenue is
estimated to be approximately $11.2 billion for mines employing 500 or
fewer employees. Thus, the yearly cost of the final rule for mines that
have 500 or fewer employees is 0.36 percent of annual revenue. Using
SBA's definition of a small mine (one having 500 or fewer employees),
the yearly cost for underground coal mines to comply with the final
rule is less than 1 percent of estimated annual revenue. Accordingly,
MSHA has certified that the final rule does not have a significant
impact on a substantial number of small entities.
VII. Paperwork Reduction Act of 1995
A. Summary
The information collection requirements contained in the final rule
are listed by the Office of Management and Budget (OMB) under control
numbers 1219-0142 and 1219-0088.
The final rule contains information collection requirements that
MSHA estimates will result in 33,560 burden hours and approximately
$2.36 million related burden costs to mine operators and seal
manufacturers. This final rule contains information collection
requirements in the following sections: Sec. 75.335 seal requirements,
strengths, design applications, and installation; Sec. 75.336 sampling
and monitoring requirements; Sec. 75.337 construction and repair of
seals; and Sec. 75.338 training.
A detailed explanation of the burden hours and related costs are in
the Paperwork Reduction Act section of the Regulatory Economic Analysis
(REA) for the final rule. The REA is located on MSHA's Web site at
http://www.msha.gov/REGSINFO.HTM. A print copy of the REA can be
obtained from MSHA's Office of Standards, Regulations, and Variances.
B. Details
The information collection package has been submitted to the Office
of Management and Budget (OMB) for review under 44 U.S.C. 3504(h) of
the Paperwork Reduction Act of 1995, as amended. A copy of the
information collection package can be obtained from the Department of
Labor by e-mail request to king.darrin@dol.gov or by phone request at
(202) 693-4129.
The information collection package for the ETS, which also served
as the proposal for this final rule, was approved by OMB under control
numbers 1219-0142, for Sealing of Abandoned Areas; and 1219-0088, for
Ventilation Plans, Tests, and Examinations in Underground Coal Mines.
MSHA estimated that the information collection requirements in the ETS
would result in 82,037 annual burden hours and approximately $4.7
million in related annual burden costs. MSHA has reduced these
estimates in the final rule to 33,553 annual burden hours and
approximately $2.36 million related annual burden costs. MSHA's
estimated reduction in burden hours is due to: (1) The removal of
approximately 41,600 hours of sampling time that was inadvertently
included with recordkeeping time and counted as paperwork; (2) the
removal of approximately 900 hours of time to prepare for training that
was inadvertently included as paperwork; (3) the removal of
approximately 3,000 hours of paperwork associated with the deleted
requirement for a sampling protocol and action plan; and (4)
approximately 3,000 hours of paperwork due to various other changes in
the final rule.
Several commenters raised concerns regarding the ETS requirement
that multiple persons must certify that seal construction was done
correctly. These comments are addressed in earlier sections of this
preamble.
VIII. Other Regulatory Considerations
A. The Unfunded Mandates Reform Act of 1995
MSHA has reviewed the final rule under the Unfunded Mandates Reform
Act of 1995 (2 U.S.C. 1501 et seq). MSHA has determined that the final
rule does not include any federal mandate that may result in increased
expenditures by State, local, or tribal governments; nor will it
increase private sector expenditures by more than $100
[[Page 21205]]
million in any one year or significantly or uniquely affect small
governments. Accordingly, the Unfunded Mandates Reform Act of 1995 (2
U.S.C. 1501 et seq) requires no further agency action or analysis.
B. The Treasury and General Government Appropriations Act of 1999:
Assessment of Federal Regulations and Policies on Families
Section 654 of the Treasury and General Government Appropriations
Act of 1999 (5 U.S.C. 601 note) requires agencies to assess the impact
of Agency action on family well-being. MSHA has determined that the
final rule has no effect on family stability or safety, marital
commitment, parental rights and authority, or income or poverty of
families and children. Accordingly, MSHA certifies that the final rule
does not impact family well-being.
C. Executive Order 12630: Government Actions and Interference With
Constitutionally Protected Property Rights
The final rule does not implement a policy with takings
implications. Accordingly, under E.O. 12630, no further Agency action
or analysis is required.
D. Executive Order 12988: Civil Justice Reform
The final rule was written to provide a clear legal standard for
affected conduct and was carefully reviewed to eliminate drafting
errors and ambiguities, so as to minimize litigation and undue burden
on the Federal court system. Accordingly, the final rule meets the
applicable standards provided in section 3 of E.O. 12988, Civil Justice
Reform.
E. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks
The final rule has no adverse impact on children. Accordingly,
under E.O. 13045, no further Agency action or analysis is required.
F. Executive Order 13132: Federalism
The final rule does not have ``federalism implications'' because it
does not ``have substantial direct effects on the States, on the
relationship between the national government and the States, or on the
distribution of power and responsibilities among the various levels of
government.'' Accordingly, under E.O. 13132, no further Agency action
or analysis is required.
G. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments
The final rule does not have ``tribal implications'' because it
will not ``have substantial direct effects on one or more Indian
tribes, on the relationship between the Federal government and Indian
tribes, or on the distribution of power and responsibilities between
the Federal government and Indian tribes.'' Accordingly, under E.O.
13175, no further Agency action or analysis is required.
H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
Executive Order 13211 requires agencies to publish a statement of
energy effects when a rule has a significant energy action that
adversely affects energy supply, distribution or use. MSHA has reviewed
the final rule for its energy effects because the final rule applies to
the underground mining sector. Because this final rule will result in
yearly costs of approximately $45.4 million to the underground coal
mining industry, relative to annual revenues of $14.1 billion in 2007,
MSHA has concluded that it is not a significant energy action because
it is not likely to have a significant adverse effect on the supply,
distribution, or use of energy. Accordingly, under this analysis, no
further Agency action or analysis is required.
I. Executive Order 13272: Proper Consideration of Small Entities in
Agency Rulemaking
MSHA has thoroughly reviewed the final rule to assess and take
appropriate account of its potential impact on small businesses, small
governmental jurisdictions, and small organizations. MSHA has
determined and certified that the final rule will not have a
significant economic impact on a substantial number of small entities.
IX. References
ACI 318-05, ``Building Code Requirements for Structural Concrete and
Commentary,'' American Concrete Institute.
ACI 440.2R-02, ``Design and Construction of Externally Bonded FRP
Systems for Strengthening Concrete Structures,'' American Concrete
Institute.
Army TM 5-1300, Navy NAVFAC P0397, Air Force AFR 88-22, Departments
of the Army, the Navy, and the Air Force, ``Structures to Resist the
Effects of Accidental Explosions,'' November 1990.
ASTM E119-07, ``Standard Test Methods for Fire Tests of Building
Construction and Materials,'' ASTM International.
ASTM E162-06, ``Surface Flammability of Materials Using a Radiant
Heat Energy Source,'' ASTM International.
Coward, H.F. and G.W. Jones, ``Limits of Flammability of Gases and
Vapors,'' Bulletin 503, U.S. Dept. of the Interior, Bureau of Mines,
1952.
Department of Labor, Mine Safety and Health Administration, Final
Rule, Underground Coal Mine Ventilation Standards, May 15, 1992.
Kissell, Fred N., ``Handbook for Methane Control in Mining,''
Information Circular 9486. National Institute of Occupational Safety
and Health, U.S. Dept. of Health and Human Services, 2006.
Mitchell, Donald W., ``Explosion-Proof Bulkheads--Present
Practices,'' Report of Investigations No. 7581, U.S. Dept. of the
Interior, Bureau of Mines, 1971.
Mitchell, Donald W., Burns, Frank A., ``Interpreting the State of a
Mine Fire,'' Investigational Report No. 1103, U.S. Department of
Labor, Mine Safety and Health Administration, 1979.
MSHA. Report of Investigation/Mine Explosion, Sago Mine, January 2,
2006.
MSHA. Report of Investigation/Mine Explosion, Darby Mine No. 1, May
20, 2006.
MSHA. Program Information Bulletin No. P06-11, ``Moratorium on
Future Use of Alternative Seal Methods and Materials Pursuant to 30
CFR 75.335 and Assessment of Existing Sealed Areas in Underground
Bituminous Coal Mines,'' June 1, 2006.
MSHA. Program Information Bulletin No. P06-12, ``Reissued Moratorium
on Future Use of Alternative Seal Methods and Materials Pursuant to
30 CFR 75.335 and Assessment of Existing Sealed Areas in Underground
Bituminous Coal Mines,'' June 12, 2006.
MSHA. Program Information Bulletin No. P06-14, ``Reissued Moratorium
on Future Use of Alternative Seal Methods and Materials Pursuant to
30 CFR 75.335 and Assessment of Existing Sealed Areas in Underground
Bituminous Coal Mines,'' June 21, 2006.
MSHA. Program Information Bulletin No. P06-16, ``Use of Alternative
Seal Methods and Materials Pursuant to 30 CFR 75.335(a)(2),'' July
19, 2006.
MSHA. Procedure Instruction Letter No. I06-V-9, ``Procedures for
Approval of Alternative Seals,'' August 21, 2006.
MSHA. Program Policy Manual, Volume V--Coal Mines, Release V-33,
February 2003.
MSHA, Approval and Certification Center, Application Cancellation
Policy, CDS No. APOL1009, Revised February 27, 2004.
Zipf, R. K., Sapko, M. J., Brune, J. F., ``Explosion Pressure Design
Criteria for New Seals in U.S. Coal Mines, Draft Report,'' National
Institute of Occupational Safety and Health, U.S. Dept. of Health
and Human Services, February 8, 2007.
Zipf, R. K., Sapko, M. J., Brune, J. F., Information Circular-9500,
``Explosion Pressure Design Criteria for New Seals in U.S. Coal
Mines,'' National Institute of Occupational Safety and Health, U.S.
Dept. of Health and Human Services, July 2007.
[[Page 21206]]
List of Subjects in 30 CFR Part 75
Mine safety and health, Reporting and recordkeeping requirements,
Underground coal mines, Ventilation.
Dated: April 14, 2008.
Richard E. Stickler,
Acting Assistant Secretary for Mine Safety and Health.
0
Chapter I of Title 30, part 75 of the Code of Federal Regulations is
amended as follows:
PART 75--MANDATORY SAFETY STANDARDS--UNDERGROUND COAL MINES
0
1. The authority citation for part 75 continues to read as follows:
Authority: 30 U.S.C. 811.
0
2. Revise Sec. 75.335 to read as follows:
Sec. 75.335 Seal strengths, design applications, and installation.
(a) Seal strengths. Seals constructed on or after October 20, 2008
shall be designed, constructed, and maintained to withstand--
(1)(i) At least 50-psi overpressure when the atmosphere in the
sealed area is monitored and maintained inert and designed using a
pressure-time curve with an instantaneous overpressure of at least 50
psi. A minimum overpressure of at least 50 psi shall be maintained for
at least four seconds then released instantaneously.
(ii) Seals constructed to separate the active longwall panel from
the longwall panel previously mined shall be designed using a pressure-
time curve with a rate of pressure rise of at least 50 psi in 0.1
second. A minimum overpressure of at least 50 psi shall be maintained;
or
(2)(i) Overpressures of at least 120 psi if the atmosphere in the
sealed area is not monitored, is not maintained inert, the conditions
in paragraphs (a)(3)(i) through (iii) of this section are not present,
and the seal is designed using a pressure-time curve with an
instantaneous overpressure of at least 120 psi. A minimum overpressure
of 120 psi shall be maintained for at least four seconds then released
instantaneously.
(ii) Seals constructed to separate the active longwall panel from
the longwall panel previously mined shall be designed using a pressure-
time curve with a rate of pressure rise of 120 psi in 0.25 second. A
minimum overpressure of 120 psi shall be maintained; or
(3) Overpressures greater than 120 psi if the atmosphere in the
sealed area is not monitored and is not maintained inert, and
(i) The atmosphere in the sealed area is likely to contain
homogeneous mixtures of methane between 4.5 percent and 17.0 percent
and oxygen exceeding 17.0 percent throughout the entire area;
(ii) Pressure piling could result in overpressures greater than 120
psi in the area to be sealed; or
(iii) Other conditions are encountered, such as the likelihood of a
detonation in the area to be sealed.
(iv) Where the conditions in paragraphs (a)(3)(i), (ii), or (iii)
of this section are encountered, the mine operator shall revise the
ventilation plan to address the potential hazards. The plan shall
include seal strengths sufficient to address such conditions.
(b) Seal design applications. Seal design applications from seal
manufacturers or mine operators shall be in accordance with paragraphs
(b)(1) or (b)(2) of this section and submitted for approval to MSHA's
Office of Technical Support, Pittsburgh Safety and Health Technology
Center, P.O. Box 18233, Cochrans Mill Road, Pittsburgh, PA 15236.
(1) An engineering design application shall--
(i) Address gas sampling pipes, water drainage systems, methods to
reduce air leakage, pressure-time curve, fire resistance
characteristics, flame spread index, entry size, engineering design and
analysis, elasticity of design, material properties, construction
specifications, quality control, design references, and other
information related to seal construction;
(ii) Be certified by a professional engineer that the design of the
seal is in accordance with current, prudent engineering practices and
is applicable to conditions in an underground coal mine; and
(iii) Include a summary of the installation procedures related to
seal construction; or
(2) Each application based on full-scale explosion tests or
equivalent means of physical testing shall address the following
requirements to ensure that a seal can reliably meet the seal strength
requirements:
(i) Certification by a professional engineer that the testing was
done in accordance with current, prudent engineering practices for
construction in a coal mine;
(ii) Technical information related to the methods and materials;
(iii) Supporting documentation;
(iv) An engineering analysis to address differences between the
seal support during test conditions and the range of conditions in a
coal mine; and
(v) A summary of the installation procedures related to seal
construction.
(3) MSHA will notify the applicant if additional information or
testing is required. The applicant shall provide this information,
arrange any additional or repeat tests, and provide prior notification
to MSHA of the location, date, and time of such test(s).
(4) MSHA will notify the applicant, in writing, whether the design
is approved or denied. If the design is denied, MSHA will specify, in
writing, the deficiencies of the application, or necessary revisions.
(5) Once the seal design is approved, the approval holder shall
promptly notify MSHA, in writing, of all deficiencies of which they
become aware.
(c) Seal installation approval. The installation of the approved
seal design shall be subject to approval in the ventilation plan. The
mine operator shall--
(1) Retain the seal design approval and installation information
for as long as the seal is needed to serve the purpose for which it was
built.
(2) Designate a professional engineer to conduct or have oversight
of seal installation and certify that the provisions in the approved
seal design specified in this section have been addressed and are
applicable to conditions at the mine. A copy of the certification shall
be submitted to the District Manager with the information provided in
paragraph (c)(3) of this section and a copy of the certification shall
be retained for as long as the seal is needed to serve the purpose for
which it was built.
(3) Provide the following information for approval in the
ventilation plan--
(i) The MSHA Technical Support Approval Number;
(ii) A summary of the installation procedures;
(iii) The mine map of the area to be sealed and proposed seal
locations that include the deepest points of penetration prior to
sealing. The mine map shall be certified by a professional engineer or
a professional land surveyor.
(iv) Specific mine site information, including--
(A) Type of seal;
(B) Safety precautions taken prior to seal achieving design
strength;
(C) Methods to address site-specific conditions that may affect the
strength and applicability of the seal including set-back distances;
(D) Site preparation;
(E) Sequence of seal installations;
(F) Projected date of completion of each set of seals;
[[Page 21207]]
(G) Supplemental roof support inby and outby each seal;
(H) Water flow estimation and dimensions of the water drainage
system through the seals;
(I) Methods to ventilate the outby face of seals once completed;
(J) Methods and materials used to maintain each type of seal;
(K) Methods to address shafts and boreholes in the sealed area;
(L) Assessment of potential for overpressures greater than 120 psi
in sealed area;
(M) Additional sampling locations; and
(N) Additional information required by the District Manager.
0
3. Revise Sec. 75.336 to read as follows:
Sec. 75.336 Sampling and monitoring requirements.
(a) A certified person as defined in Sec. 75.100 shall monitor
atmospheres of sealed areas. Sealed areas shall be monitored, whether
ingassing or outgassing, for methane and oxygen concentrations and the
direction of leakage.
(1) Each sampling pipe and approved sampling location shall be
sampled at least every 24 hours.
(i) Atmospheres with seals of 120 psi or greater shall be sampled
until the design strength is reached for every seal used to seal the
area.
(ii) Atmospheres with seals less than 120 psi constructed before
October 20, 2008 shall be monitored for methane and oxygen
concentrations and maintained inert. The operator may request that the
District Manager approve different sampling locations and frequencies
in the ventilation plan, provided at least one sample is taken at each
set of seals at least every 7 days.
(iii) Atmospheres with seals less than 120 psi constructed after
October 20, 2008 shall be monitored for methane and oxygen
concentrations and maintained inert. The operator may request that the
District Manager approve different sampling locations and frequencies
in the ventilation plan after a minimum of 14 days and after the seal
design strength is reached, provided at least one sample is taken at
each set of seals at least every 7 days.
(2) The mine operator shall evaluate the atmosphere in the sealed
area to determine whether sampling through the sampling pipes in seals
and approved locations provides appropriate sampling locations of the
sealed area. The mine operator shall make the evaluation immediately
after the minimum 14-day required sampling, if the mine ventilation
system is reconfigured, if changes occur that adversely affect the
sealed area, or if the District Manager requests an evaluation. When
the results of the evaluations indicate the need for additional
sampling locations, the mine operator shall provide the additional
locations and have them approved in the ventilation plan. The District
Manager may require additional sampling locations and frequencies in
the ventilation plan.
(3) Mine operators with an approved ventilation plan addressing
spontaneous combustion pursuant to Sec. 75.334(f) shall sample the
sealed atmosphere in accordance with the ventilation plan.
(4) The District Manager may approve in the ventilation plan the
use of a continuous monitoring system in lieu of monitoring provisions
in this section.
(b)(1) Except as provided in Sec. 75.335(d), the atmosphere in the
sealed area is considered inert when the oxygen concentration is less
than 10.0 percent or the methane concentration is less than 3.0 percent
or greater than 20.0 percent.
(2) Immediate action shall be taken by the mine operator to restore
an inert sealed atmosphere behind seals with strengths less than 120
psi. Until the atmosphere in the sealed area is restored to an inert
condition, the sealed atmosphere shall be monitored at each sampling
pipe and approved location at least once every 24 hours.
(c) Except as provided in Sec. 75.335(d), when a sample is taken
from the sealed atmosphere with seals of less than 120 psi and the
sample indicates that the oxygen concentration is 10 percent or greater
and methane is between 4.5 percent and 17 percent, the mine operator
shall immediately take an additional sample and then immediately notify
the District Manager. When the additional sample indicates that the
oxygen concentration is 10 percent or greater and methane is between
4.5 percent and 17 percent, persons shall be withdrawn from the
affected area which is the entire mine or other affected area
identified by the operator and approved by the District Manager in the
ventilation plan, except those persons referred to in Sec. 104(c) of
the Act. The operator may identify areas in the ventilation plan to be
approved by the District Manager where persons may be exempted from
withdrawal. The operator's request shall address the location of seals
in relation to: Areas where persons work and travel in the mine;
escapeways and potential for damage to the escapeways; and ventilation
systems and controls in areas where persons work or travel and where
ventilation is used for escapeways. The operator's request shall also
address the gas concentration of other sampling locations in the sealed
area and other required information. Before miners reenter the mine,
the mine operator shall have a ventilation plan revision approved by
the District Manager specifying the actions to be taken.
(d) In sealed areas with a demonstrated history of carbon dioxide
or sealed areas where inert gases have been injected, the operator may
request that the District Manager approve in the ventilation plan an
alternative method to determine if the sealed atmosphere is inert and
when miners have to be withdrawn. The mine operator shall address in
the ventilation plan the specific levels of methane, carbon dioxide,
nitrogen and oxygen; the sampling methods and equipment used; and the
methods to evaluate these concentrations underground at the seal.
(e) Recordkeeping. (1) The certified person shall promptly record
each sampling result including the location of the sampling points,
whether ingassing or outgassing, and oxygen and methane concentrations.
The results of oxygen and methane samples shall be recorded as the
percentage of oxygen and methane measured by the certified person and
any hazardous condition found in accordance with Sec. 75.363.
(2) The mine operator shall retain sampling records at the mine for
at least one year from the date of the sampling.
0
4. Revise Sec. 75.337 to read as follows:
Sec. 75.337 Construction and repair of seals.
(a) The mine operator shall maintain and repair seals to protect
miners from hazards of sealed areas.
(b) Prior to sealing, the mine operator shall--
(1) Remove insulated cables, batteries, and other potential
electric ignition sources from the area to be sealed when constructing
seals, unless it is not safe to do so. If ignition sources cannot
safely be removed, seals must be constructed to at least 120 psi;
(2) Remove metallic objects through or across seals; and
(3) Breach or remove all stoppings in the first crosscut inby the
seals immediately prior to sealing the area.
(c) A certified person designated by the mine operator shall
directly supervise seal construction and repair and--
(1) Examine each seal site immediately prior to construction or
repair to ensure that the site is in accordance with the approved
ventilation plan;
(2) Examine each seal under construction or repair during each
shift to ensure that the seal is being
[[Page 21208]]
constructed or repaired in accordance with the approved ventilation
plan;
(3) Examine each seal upon completion of construction or repair to
ensure that construction or repair is in accordance with the approved
ventilation plan;
(4) Certify by initials, date, and time that the examinations were
made; and
(5) Make a record of the examination at the completion of any shift
during which an examination was conducted. The record shall include
each deficiency and the corrective action taken. The record shall be
countersigned by the mine foreman or equivalent mine official by the
end of the mine foreman's or equivalent mine official's next regularly
scheduled working shift. The record shall be kept at the mine for one
year.
(d) Upon completion of construction of each seal a senior mine
management official, such as a mine manager or superintendent, shall
certify that the construction, installation, and materials used were in
accordance with the approved ventilation plan. The mine operator shall
retain the certification for as long as the seal is needed to serve the
purpose for which it was built.
(e) The mine operator shall--
(1) Notify the District Manager between two and fourteen days prior
to commencement of seal construction;
(2) Notify the District Manager, in writing, within five days of
completion of a set of seals and provide a copy of the certification
required in paragraph (d) of this section; and
(3) Submit a copy of quality control results to the District
Manager for seal material properties specified by Sec. 75.335 within
30 days of completion of quality control tests.
(f) Welding, cutting, and soldering. Welding, cutting, and
soldering with an arc or flame are prohibited within 150 feet of a
seal. An operator may request a different location in the ventilation
plan to be approved by the District Manager. The operator's request
must address methods the mine operator will use to continuously monitor
atmospheric conditions in the sealed area during welding or burning;
the airflow conditions in and around the work area; the rock dust and
water application methods; the availability of fire extinguishers on
hand; the procedures to maintain safe conditions, and other relevant
factors.
(g) Sampling pipes. (1) For seals constructed after April 18, 2008,
one non-metallic sampling pipe shall be installed in each seal that
shall extend into the center of the first connecting crosscut inby the
seal. If an open crosscut does not exist, the sampling pipe shall
extend one-half of the distance of the open entry inby the seal.
(2) Each sampling pipe shall be equipped with a shut-off valve and
appropriate fittings for taking gas samples.
(3) The sampling pipes shall be labeled to indicate the location of
the sampling point when more than one sampling pipe is installed
through a seal.
(4) If a new seal is constructed to replace or reinforce an
existing seal with a sampling pipe, the sampling pipe in the existing
seal shall extend through the new seal. An additional sampling pipe
shall be installed through each new seal to sample the area between
seals, as specified in the approved ventilation plan.
(h) Water drainage system. For each set of seals constructed after
April 18, 2008, the seal at the lowest elevation shall have a
corrosion-resistant, non-metallic water drainage system. Seals shall
not impound water or slurry. Water or slurry shall not accumulate
within the sealed area to any depth that can adversely affect a seal.
0
5. Revise Sec. 75.338 to read as follows:
Sec. 75.338 Training.
(a) Certified persons conducting sampling shall be trained in the
use of appropriate sampling equipment, procedures, location of sampling
points, frequency of sampling, size and condition of the sealed area,
and the use of continuous monitoring systems if applicable before they
conduct sampling, and annually thereafter. The mine operator shall
certify the date of training provided to certified persons and retain
each certification for two years.
(b) Miners constructing or repairing seals, designated certified
persons, and senior mine management officials shall be trained prior to
constructing or repairing a seal and annually thereafter. The training
shall address materials and procedures in the approved seal design and
ventilation plan. The mine operator shall certify the date of training
provided each miner, certified person, and senior mine management
official and retain each certification for two years.
0
6. Add Sec. 75.339 to read as follows:
Sec. 75.339 Seals records.
(a) The table entitled ``Seal Recordkeeping Requirements'' lists
records the operator shall maintain and the retention period for each
record.
Table--Sec. 75.339(a) Seal Recordkeeping Requirements
------------------------------------------------------------------------
Record Section reference Retention time
------------------------------------------------------------------------
(1) Approved seal design...... 75.335(c)(1)..... As long as the seal
is needed to serve
the purpose for
which it is built.
(2) Certification of 75.335(c)(2)..... As long as the seal
Provisions of Approved Seal is needed to serve
Design is Addressed. the purpose for
which it is built.
(3) Gas sampling records...... 75.336(e)(2)..... 1 year.
(4) Record of examinations.... 75.337(c)(5)..... 1 year.
(5) Certification of seal 75.337(d)........ As long as the seal
construction, installation, is needed to serve
and materials. the purpose for
which it is built.
(6) Certification of Training 75.338(a)........ 2 years.
for Persons that Sample.
(7) Certification of Training 75.338(b)........ 2 years.
for Persons that Perform Seal
Construction and Repair.
------------------------------------------------------------------------
(b) Records required by Sec. Sec. 75.335, 75.336, 75.337 and
75.338 shall be retained at a surface location at the mine in a secure
book that is not susceptible to alteration. The records may be retained
electronically in a computer system that is secure and not susceptible
to alteration, if the mine operator can immediately access the record
from the mine site.
(c) Upon request from an authorized representative of the Secretary
of Labor, the Secretary of Health and Human Services, or from the
authorized representative of miners, mine operators shall promptly
provide access to any record listed in the table in this section.
[[Page 21209]]
(d) Whenever an operator ceases to do business or transfers control
of the mine to another entity, that operator shall transfer all records
required to be maintained by this part, or a copy thereof, to any
successor operator who shall maintain them for the required period.
0
7. Amend Sec. 75.371 by revising paragraph (ff) to read as follows:
Sec. 75.371 Mine ventilation plan; contents.
* * * * *
(ff) Seal installation requirements provided by Sec. 75.335 and
the sampling provisions provided by Sec. 75.336.
* * * * *
[FR Doc. 08-1152 Filed 4-16-08; 2:14 pm]
BILLING CODE 4510-43-P