30 CFR § 75.351
Atmospheric monitoring system (AMS).
(a) AMS operation. Whenever personnel are underground and an AMS is
used to fulfill the requirements of § § 75.323(d)(1)(ii),
75.340(a)(1)(ii), 75.340(a)(2)(ii), 75.350(b), 75.350(d), or 75.362(f),
the AMS must be operating and a designated AMS operator must be on duty
at a location on the surface of the mine where audible and visual
signals from the AMS must be seen or heard and the AMS operator can
promptly respond to these signals.
(b) Designated surface location and AMS operator. When an AMS is
used to comply with § § 75.323(d)(1)(ii), 75.340(a)(1)(ii),
75.340(a)(2)(ii), 75.350(b), 75.350(d), or 75.362(f), the following
requirements apply:
(1) The mine operator must designate a surface location at the mine
where signals from the AMS will be received and two-way voice
communication is maintained with each working section, with areas where
mechanized mining equipment is being installed or removed, and with
other areas designated in the approved emergency evacuation and
firefighting program of instruction (§ 75.1502).
(2) The mine operator must designate an AMS operator to monitor and
promptly respond to all AMS signals.
(3) A map or schematic must be provided at the designated surface
location that shows the locations and type of AMS sensor at each
location, and the intended air flow direction at these locations. This
map or schematic must be updated within 24 hours of any change in this
information.
(4) The names of the designated AMS operators and other appropriate
personnel, including the designated person responsible for initiating
an emergency mine evacuation under § 75.1501, and the method to
contact these persons, must be provided at the designated surface
location.
(c) Minimum operating requirements. AMSs used to comply with
§ § 75.323(d)(1)(ii), 75.340(a)(1)(ii), 75.340(a)(2)(ii),
75.350(b), 75.350(d), or 75.362(f) must:
(1) Automatically provide visual and audible signals at the
designated surface location for any interruption of circuit continuity
and any electrical malfunction of the system. These signals must be of
sufficient magnitude to be seen or heard by the AMS operator.
(2) Automatically provide visual and audible signals at the
designated surface location when the carbon monoxide concentration or
methane concentration at any sensor reaches the alert level as
specified in § 75.351(i). These signals must be of sufficient
magnitude to be seen or heard by the AMS operator.
(3) Automatically provide visual and audible signals at the
designated surface location distinguishable from alert signals when the
carbon monoxide, smoke, or methane concentration at any sensor reaches
the alarm level as specified in § 75.351(i). These signals must be
of sufficient magnitude to be seen or heard by the AMS operator.
(4) Automatically provide visual and audible signals at all
affected working sections and at all affected areas where mechanized
mining equipment is being installed or removed when the carbon
monoxide, smoke, or methane concentration at any sensor reaches the
alarm level as specified in § 75.351(i). These signals must be of
sufficient magnitude to be seen or heard by miners working at these
locations. Methane signals must be distinguishable from other signals.
(5) Automatically provide visual and audible signals at other
locations as specified in Mine Emergency Evacuation and Firefighting
Program of Instruction (§ 75.1502) when the carbon monoxide, smoke,
or methane concentration at any sensor reaches the alarm level as
specified in § 75.351(i). These signals must be seen or heard by
miners working at these locations. Methane alarms must be
distinguishable from other signals.
(6) Identify at the designated surface location the operational
status of all sensors.
(7) Automatically provide visual and audible alarm signals at the
designated surface location, at all affected working sections, and at
all affected areas where mechanized mining equipment is being installed
or removed when the carbon monoxide level at any two consecutive
sensors alert at the same time. These signals must be seen or heard by
the AMS operator and miners working at these locations.
(d) Location and installation of AMS sensors. (1) All AMS sensors,
as specified in § § 75.351(e) through 75.351(h), must be located
such that measurements are representative of the mine atmosphere in
these locations.
(2) Carbon monoxide or smoke sensors must be installed near the
center in the upper third of the entry, in a location that does not
expose personnel working on the system to unsafe conditions. Sensors
must not be located in abnormally high areas or in other locations where air flow patterns do not permit products of combustion to be carried to the sensors.
(3) Methane sensors must be installed near the center of the entry,
at least 12 inches from the roof, ribs, and floor, in a location that
would not expose personnel working on the system to unsafe conditions.
(e) Location of sensors--belt air course. In addition to the
requirements of paragraph (d) of this section, any AMS used to monitor
belt air courses under § 75.350(b) must have sensors to monitor for
carbon monoxide or smoke at the following locations:
(1) At or near the working section belt tailpiece in the air stream
ventilating the belt entry. In longwall mining systems the sensor must
be located upwind in the belt entry at a distance no greater than 150
feet from the mixing point where intake air is mixed with the belt air
at or near the tailpiece;
(2) Upwind, a distance no greater than 50 feet from the point where
the belt air course is combined with another air course or splits into
multiple air courses;
(3) At intervals not to exceed 1,000 feet along each belt entry in
areas where air velocities are maintained at 50 feet per minute or
higher. In areas along each belt entry where air velocities are less
than 50 feet per minute, the sensor spacing must not exceed 350 feet.
All sensors must be installed at the 1,000-foot spacing no later than
August 2, 2004.
(4) Not more than 100 feet downwind of each belt drive unit, each
tailpiece transfer point, and each belt take-up. If the belt drive,
tailpiece, and/or take-up for a single transfer point are installed
together in the same air course they may be monitored with one sensor
located not more than 100 feet downwind of the last component; and
(5) At other locations in any entry that is part of the belt air
course as required and specified in the mine ventilation plan.
(f) Locations of sensors--the primary escapeway. When used to
monitor the primary escapeway under § 75.350(b)(4), carbon monoxide
or smoke sensors must be located in the primary escapeway within 500
feet of the working section and areas where mechanized mining equipment
is being installed or removed. In addition, another sensor must be
located within 500 feet inby the beginning of the panel. The point-feed
sensor required by § 75.350(d)(1) may be used as the sensor at the
beginning of the panel if it is located within 500 feet inby the
beginning of the panel.
(g) Location of sensors--return air splits. (1) If used to monitor
return air splits under § 75.362(f), a methane sensor must be
installed in the return air split between the last working place,
longwall or shortwall face ventilated by that air split, and the
junction of the return air split with another air split, seal, or
worked out area.
(2) If used to monitor a return air split under §
75.323(d)(1)(ii), the methane sensors must be installed at the
following locations:
(i) In the return air course opposite the section loading point,
or, if exhausting auxiliary fan(s) are used, in the return air course
no closer than 300 feet downwind from the fan exhaust and at a point
opposite or immediately outby the section loading point; and
(ii) Immediately upwind from the location where the return air
split meets another air split or immediately upwind of the location
where an air split is used to ventilate seals or worked-out areas.
(h) Location of sensors--electrical installations. When monitoring
the intake air ventilating underground transformer stations, battery
charging stations, substations, rectifiers, or water pumps under §
75.340(a)(1)(ii) or § 75.340(a)(2)(ii), at least one sensor must be
installed to monitor the mine atmosphere for carbon monoxide or smoke,
located downwind and not greater than 50 feet from the electrical
installation being monitored.
(i) Establishing alert and alarm levels. An AMS installed in
accordance with the following paragraphs must initiate alert and alarm
signals at the specified levels, as indicated:
(1) For § 75.323(d)(1)(ii) alarm at 1.5% methane.
(2) For § § 75.340(a)(1)(ii), 75.340(a)(2)(ii), 75.350(b),
and 75.350(d), alert at 5 ppm carbon monoxide above the ambient level
and alarm at 10 ppm carbon monoxide above the ambient level when carbon
monoxide sensors are used; and alarm at a smoke optical density of
0.022 per meter when smoke sensors are used. Reduced alert and alarm
settings approved by the district manager may be required for carbon
monoxide sensors identified in the mine ventilation plan, §
75.371(nn).
(3) For § 75.362(f), alert at 1.0% methane and alarm at 1.5%
methane.
(j) Establishing carbon monoxide ambient levels. Carbon monoxide
ambient levels and the means to determine these levels must be approved
in the mine ventilation plan (§ 75.371(hh)) for monitors installed
in accordance with § § 75.340(a)(1)(ii), 75.340(a)(2)(ii),
75.350(b), and 75.350(d).
(k) Installation and maintenance. An AMS installed in accordance
with § § 75.323(d)(1)(ii), 75.340(a)(1)(ii), 75.340(a)(2)(ii),
75.350(b), 75.350(d), or 75.362(f) must be installed and maintained by
personnel trained in the installation and maintenance of the system.
The system must be maintained in proper operating condition.
(l) Sensors. Sensors used to monitor for carbon monoxide, methane,
and smoke must be either of a type listed and installed in accordance
with the recommendations of a nationally recognized testing laboratory
approved by the Secretary; or these sensors must be of a type, and
installed in a manner, approved by the Secretary.
(m) Time delays. When a demonstrated need exists, time delays may
be incorporated into the AMS. These time delays must only be used to
account for non-fire related carbon monoxide alert and alarm sensor
signals. These time delays are limited to no more than three minutes.
The use and length of any time delays, or other techniques or methods
which eliminate or reduce the need for time delays, must be specified
and approved in the mine ventilation plan.
(n) Examination, testing, and calibration. (1) At least once each
shift when belts are operated as part of a production shift, sensors
used to detect carbon monoxide or smoke in accordance with § §
75.350(b), and 75.350(d), and alarms installed in accordance with §
75.350(b) must be visually examined.
(2) At least once every seven days, alarms for AMS installed in
accordance with § § 75.350(b), and 75.350(d) must be
functionally tested for proper operation.
(3) At intervals not to exceed 31 days--
(i) Each carbon monoxide sensor installed in accordance with
§ § 75.340(a)(1)(ii), 75.340(a)(2)(ii), 75.350(b), or 75.350(d)
must be calibrated in accordance with the manufacturer's calibration
specifications. Calibration must be done with a known concentration of
carbon monoxide in air sufficient to activate the alarm;
(ii) Each smoke sensor installed in accordance with § §
75.340(a)(1)(ii), 75.340(a)(2)(ii), 75.350(b), or 75.350(d) must be
functionally tested in accordance with the manufacturer's calibration
specifications;
(iii) Each methane sensor installed in accordance with § §
75.323(d)(1)(ii) or 75.362(f) must be calibrated in accordance with the
manufacturer's calibration specifications. Calibration must be done
with a known concentration of methane in air sufficient to activate an
alarm.
(iv) If the alert or alarm signals will be activated during
calibration of sensors, the AMS operator must be notified prior to and
upon completion of calibration. The AMS operator must notify miners on
affected working sections, areas where mechanized mining equipment is
being installed or removed, or other areas designated in the approved
emergency evacuation and firefighting program of instruction (§
75.1502) when calibration will activate alarms and when calibration is
completed.
(4) Gases used for the testing and calibration of AMS sensors must
be traceable to the National Institute of Standards and Technology
reference standard for the specific gas. When these reference standards
are not available for a specific gas, calibration gases must be
traceable to an analytical standard which is prepared using a method
traceable to the National Institute of Standards and Technology.
Calibration gases must be within 2.0 percent of
the indicated gas concentration.
(o) Recordkeeping. (1) When an AMS is used to comply with
§ § 75.323(d)(1)(ii), 75.340(a)(1)(ii), 75.340(a)(2)(ii),
75.350(b), 75.350(d), or 75.362(f), individuals designated by the
operator must make the following records by the end of the shift in
which the following event(s) occur:
(i) If an alert or alarm signal occurs, a record of the date, time,
location and type of sensor, and the cause for the activation.
(ii) If an AMS malfunctions, a record of the date, the extent and
cause of the malfunction, and the corrective action taken to return the
system to proper operation.
(iii) A record of the seven-day tests of alert and alarm signals;
calibrations; and maintenance of the AMS must be made by the person(s)
performing these actions.
(2) The person entering the record must include their name, date,
and signature in the record.
(3) The records required by this section must be kept either in a
secure book that is not susceptible to alteration, or electronically in
a computer system that is secure and not susceptible to alteration.
These records must be maintained separately from other records and
identifiable by a title, such as the `AMS log.'
(p) Retention period. Records must be retained for at least one
year at a surface location at the mine and made available for
inspection by miners and authorized representatives of the Secretary.
(q) Training. All AMS operators must be trained annually in the
proper operation of the AMS. A record of the content of training, the
person conducting the training, and the date the training was
conducted, must be maintained at the mine for at least one year by the
mine operator.
(r) Communications. When an AMS is used to comply with §
75.350(b), a two-way voice communication system required by §
75.1600 must be installed in an entry that is separate from the entry
in which the AMS is installed no later than August 2, 2004. The two-way
voice communication system may be installed in the entry where the
intake sensors required by § § 75.350(b)(4) or 75.350(d)(1) are
installed.
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