U.S. Department of Labor

Mine Safety and Health Administration 1100 Wilson Boulevard Arlington, Virginia 22209-3939

FROM:           KEVIN G. STRICKLIN
                        Administrator for
                       Coal Mine Safety and Health

                       MARK E. SKILES
                       Director of Technical Support

SUBJECT:      Procedures for Inspection of Seals

Scope
This Procedure Instruction Letter (PIL) applies to all Coal Mine Safety and Health enforcement personnel and Technical Support personnel.

Purpose
The purpose of this PIL is to establish uniform procedures for the application of the Mine Safety and Health Administration (MSHA) regulations regarding seals. MSHA issued an Emergency Temporary Standard (ETS) on May 22, 2007, concerning the sealing of abandoned areas. This PIL includes guidance on seal inspections, monitoring of the sealed atmosphere and the action plan that mine operators are required to include in their ventilation plans for all sealed areas. This PIL also provides inspection guidance during seal construction.

Procedure Instruction
All seals, except those specified as gob isolation controls in the ventilation plan as part of a spontaneous combustion control plan that are no longer accessible, shall be inspected each quarter as required by current coal inspection procedures. Seals may also be inspected during 103(i) spot inspections at gassy mines. Appropriate enforcement action should be taken if any seal is not accessible for inspection. This will include withdrawal of affected persons until the situation is corrected. During the inspections, the following evaluations must be made:

1) Before going underground, review examination record books concerning seals and adjacent air courses, including the monitoring records specified in § 75.335(b)(6). The operator's sample results should be reviewed. Any hazardous conditions noted by the seal examiners that was recorded in the weekly or preshift exam books should be investigated;

2) Inspect safe access for the examiner's route of travel to and from seals. Roof support must be maintained to provide safe, long-term access to the seals. Test the ventilation that is provided to the face of the seal to determine if it provides adequate dilution of hazardous gases;

3) Verify that current date, times, and initials from required examinations, including those concerning seal construction and repair are present;

4) Inspect seals for deterioration and for structural damage such as cracking, spalling, or bulging. Inspect the base of the seal for deterioration due to mine water;

5) Inspect the strata surrounding seals for rib sloughing, roof falls or floor deterioration that may affect the integrity of the seal; and

6) Inspect sampling pipes and test the atmosphere behind the seals constructed prior to May 22, 2007, and 50 psi seals constructed after May 22, 2007.

Samples should only be taken when seals are outgassing. To the extent possible, sampling should be conducted during periods of decreasing barometric pressures. Samples must be taken from all sample pipes identified in the approved protocol. Occasionally, additional sampling may be taken from any additional sampling pipes to verify the validity of the sampling protocol or to further investigate any anomalous measurements. If significant differences are found when sampling pipes that are not specified in the protocol are sampled, the protocol should be reviewed and may need to be revised.

Equipment needed:
    Permissible sampling pump to pull sample from behind seals
    Tubing, adapters, connectors, etc.
    High range methane detector
    Oxygen detector
    Standard range methane detector (less than 5%)
    Bottles or bags to collect samples

The pumping should continue long enough to purge the sampling tube and line six times the volume of the sample system prior to extracting the sample. Do not overfill sample bags or they may rupture when transported to the analysis laboratory.

If the sealed atmosphere is clearly inert, (oxygen less than 10% or methane greater than 20% or methane less than 3%), a single sample is sufficient. If the atmosphere in the sealed area contains an oxygen concentration of greater than 10% and methane concentration between 3% and 20%, two additional measurements must be taken at one hour intervals to substantiate the potential hazard. If the additional two measurements confirm the initial findings, the action plan in the approved ventilation plan, should be followed. If an approved action plan is not available, the following should be used as action levels:


    (1) Greater than 10.0% oxygen and methane between 3.0-4.5%: the mine operator should take corrective action to ensure that an explosive mixture is not reached.
    (2) Greater than 10.0% oxygen and methane between 4.5-17.0%: An inspector should determine the affected area based on the seal location relative to working sections, escapeways and exposure of the miners.
    (3) Greater than 10.0% oxygen and methane between 17.0-20.0% methane: operator should take corrective action to ensure that an explosive mixture is not reached.

Depending on the condition, corrective action may include one or more of the following:
    (1) Inject inert gas into the sealed area;
    (2) Ventilate the sealed area (an approved seal breaching plan is required);
    (3) Withdraw miners from the affected area; or
    (4) Construct a new seal that has been approved by the district manager outby the existing seal. Inspectors must collect a bottle sample or bag sample to substantiate any 107(a) order issued because of gas concentrations.

Sample results of oxygen and methane need to be included in the comments section of the seal inventory database located on the W Drive at W:\COAL\Specproj\Seal Inventory.

7) Inspect water traps for air exchange. Examine the drainage pipe system. Verify that no water has been impounded on either side of the seal. If a drainage system includes a valve, it should be opened as part of the inspection;

8) Evaluate rockdust around the seals and in the adjacent aircourse(s); and

9) Evaluate the construction of existing alternative seals (20 psi), using the MSHA guidebook entitled "Guide for Alternative Seals." Use the "Guide to Solid Concrete Block Seals," to evaluate existing solid-concrete block (Mitchell-Barrett) seal construction. These guides are available on MSHA's website at www.msha.gov < Seal Single-Source Page >. Improper construction must be corrected or an approved new seal must be built to replace the deficient seal. All new seal construction projects must be inspected by MSHA during construction. The ETS requires the mine operator to notify the local MSHA field office between 2 and 14 days prior to commencement of seal construction. An inspection, which can coincide with a quarterly inspection or 103(i) spot inspection, must be conducted during seal construction for each set of seals. The focus of this construction inspection should be to determine mine operator's compliance with the requirements of the ETS including:

    1. site preparation;
    2. sealed area preparation;
    3. seal construction;
    4. training;
    5. examinations; and
    6. record keeping.

Inspectors should examine both sides of seals under construction.

All new seals must be inspected by MSHA after construction is completed during the next inspection. The ETS requires the mine operator to notify the District Manager in writing within five days of completion of a set of seals. When possible an inspection, which can coincide with a quarterly inspection or 103(i) spot inspection, should be conducted after construction is completed. The focus of this seal completion inspection should be to determine mine operator's compliance with the requirements of the ETS including:

    1. seal construction;
    2. examinations;
    3. post-sealing ventilation;
    4. rock-dusting;
    5. sampling pipes and water drainage; and
    6. roof support.