# Safety Standards for Underground Coal Mine Ventilation

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URL: https://www.frixlaw.com/law-library/documents/fr%3A94-12054

## Record

- **Collection:** Federal Register
- **Document type:** Uncategorized Document
- **Published:** May 19, 1994

## Text

SUMMARY: This proposed rule revises stayed provisions of the Mine
Safety and Health Administration's existing safety standards for
ventilation of underground coal mines. The proposal also revises,
clarifies or reproposes certain other provisions in the rule, includes
some new provisions, and addresses concerns raised during public
informational meetings and later discussions.

DATES: Written comments must be submitted on or before July 18, 1994.
Commenters are encouraged to send comments on a computer disk along
with their original comments in hard copy.

ADDRESSES: Send written comments and computer disks to the Mine Safety
and Health Administration, Office of Standards, Regulations and
Variances, room 631, Ballston Tower No. 3, 4015 Wilson Boulevard,
Arlington, Virginia 22203.

FOR FURTHER INFORMATION CONTACT: Patricia W. Silvey, Director, Office
of Standards, Regulations and Variances, MSHA, phone (703) 235-1910.

SUPPLEMENTARY INFORMATION:

I. Paperwork Reduction Act

This proposal contains information collection requirements in
Secs. 75.312, 75.342, 75.360, 75.363, 75.364 and 75.382. These
paperwork requirements have been submitted to the Office of Management
and Budget (OMB) for review under section 3504(h) of the Paperwork
Reduction Act of 1980. The respondents would be mine operators. The
burden hour estimate for Sec. 75.312 includes the time to record any
fan monitoring system malfunctions, electrical or mechanical
deficiencies in the monitoring system and any sudden increase or loss
in mine ventilating pressure, the time for recording main mine fan
defects that are corrected and for the mine foreman and mine
superintendent to countersign the record. The burden hour estimate for
Sec. 75.342 includes the time to develop a written maintenance program,
to record the calibration tests and to file the record. The burden hour
estimate for Sec. 75.360 includes the expanded examination time and the
time for the mine superintendent to countersign the records. The burden
hour estimates for Sec. 75.362 includes the expanded examination time.
The burden hour estimate for Sec. 75.363 includes the time for
recording the hazard, the corrective action taken, the certified person
initialing the record, the mine foreman and mine superintendent
countersigning the record and for filing the record. The burden hour
estimate for Sec. 75.364 includes the time for the mine superintendent
to countersign the records. The burden hour estimate for Sec. 75.382
includes the time for recording the results of the examination, for the
mine foreman and the mine superintendent to countersign the record, and
for filing the record. The information collected would be used by MSHA
to assess compliance with the proposed requirements. The information
collection requirements contained in the proposal are discussed below.
Proposed Sec. 75.312(g)(1) would require that the records of all
defects found during the daily fan examination be made by the end of
the shift on which the examination is made. The record would be made in
a state-approved book or in a bound book with sequential machine-
numbered pages.
Proposed paragraph (g)(2)(i) would require that the certified
copies of data produced by the fan monitoring systems be maintained
separate from other computer generated reports or data.
Proposed paragraph (g)(2)(ii) would require that a record be made
of any fan monitoring system malfunction, electrical or mechanical
deficiency in the monitoring system and any sudden increase or loss in
mine ventilating pressure. The record would be made by the end of the
shift on which the review of the data is completed and would be made in
a state-approved book or in a bound book with sequential machine-
numbered pages.
Proposed paragraph (g)(3) would require that at mines permitted to
shut down main mine fans under Sec. 75.311, if a pressure recording
device is not used, a record be made of the time and fan pressure
immediately before the fan is stopped, and after the fan is restarted
and the fan pressure stabilizes. The record would be made in a state-
approved book or in a bound book with sequential machine-numbered
pages.
Proposed paragraph (g)(4) would require that a record of the
results of the tests be made by the end of the shift on which the
monthly test of the automatic fan signal device or the automatic
closing doors is completed. Persons making these tests would record the
results of the tests in a state-approved book or in a bound book with
sequential machine-numbered pages.
Proposed paragraph (g)(5) would require that the records required
under paragraphs (g)(1) through (g)(4) be countersigned by the mine
foreman, and the mine superintendent, mine manager, or other mine
official to whom the mine foreman is directly accountable.
MSHA estimates that it would take about 4 minutes for the mine
foreman and mine superintendent to countersign the records and would
take an additional 5 minutes to record main mine fan defects corrected
and an additional 10 minutes to record any fan monitoring system
malfunctions, electrical or mechanical deficiencies in the monitoring
system and any sudden increase or loss in mine ventilating pressure.
The total estimated recordkeeping burden for all affected mines would
be 29,608 hours of which large mines would incur 9,657 hours and small
mines would incur 19,951 hours.
Proposed paragraph Sec. 75.342(a)(4)(ii) would require mine
operators to develop and adopt a written maintenance program that would
have to be made available for inspection by authorized representatives
of the Secretary and the representative of miners. MSHA estimates that
it would take about 1 hour to develop a written maintenance program.
Proposed paragraph (a)(4)(iii) would require that a record of all
calibration tests of methane monitors be made in a state-approved book
or in a bound book with sequential machine-numbered pages.
Proposed paragraph (a)(4)(iv) would require the record of the
calibration tests to be kept for one year from the date of the test and
to be retained at a surface location at the mine and made available for
inspection by authorized representatives of the Secretary and the
representative of miners.
A record of calibration tests would be required to be made monthly
at all mines. MSHA estimates that it would take about 5 minutes to
complete a record. The total estimated recordkeeping burden for all
affected mines that concerns developing a written maintenance program
and maintaining a record of tests would be 2,910 hours of which large
mines would incur 1,464 hours and small mines would incur 1,446 hours.
Proposed Sec. 75.360(b)(3) would require a preshift examination to
be made for sections capable of producing coal by energizing equipment
on the section. MSHA estimates that this would affect some mines and
take up to an additional hour per examination.
Proposed paragraph (f) would require that a record of the results
of each preshift examination, including a record of hazardous
conditions and their locations found by the examiner during each
examination and of the results and locations of air and methane
measurements, be made in a book provided for that purpose on the
surface.
The record would be made by either the certified person who made
the examination or by a person designated by the operator. If the
record is made by someone other than the examiner, the examiner would
be required to verify the record by initials and date. A record would
also be made by a certified person of the action taken to correct
hazardous conditions found during the preshift examination. The records
would be countersigned by the mine foreman, and by the mine
superintendent, mine manager, or other mine official to whom the mine
foreman is directly accountable. The record would be made in a state-
approved book or in a bound book with sequential machine-numbered
pages. MSHA estimates that it would take about 2 minutes for the mine
superintendent to countersign the records.
The total estimated recordkeeping burden and the extended
examination time for all affected mines would be 60,987 hours of which
large mines would incur 56,015 hours and small mines would incur 4,972
hours.
Proposed Sec. 75.362(a)(1) would expand the on-shift examination to
include sections where anyone is assigned to work during the shift,
such as those sections where maintenance work is performed. In
addition, proposed paragraph (a)(2) would add a new requirement for on-
shift examinations to be conducted to assure compliance with the
respirable dust control parameters specified in mine ventilation plans.
MSHA estimates that these provisions will expand on-shift examinations
by up to 45 minutes. MSHA estimates that the total burden hours related
to expanding the on-shift examination would be 111,434, of which small
mines would incur 18,007 hours and large mines would incur 93,427
hours.
Proposed Sec. 75.363 would require that any hazardous conditions
discovered be posted, corrected immediately, and recorded. Proposed
paragraph (a) would require a conspicuous danger sign to be posted at
any area where hazardous conditions are found. The hazardous condition
would have to be corrected immediately and only persons designated by
the operator to correct or evaluate the condition would be allowed to
enter a posted area.
Proposed paragraph (b) would require that a record including a
description and location of the hazardous condition and the corrective
action taken be kept in a book maintained on the surface at the mine.
The record would be made by the completion of the shift on which the
hazardous condition is found. This record would not be required for
shifts when no hazardous conditions are found or for hazardous
conditions found during the preshift or weekly examinations because
these examinations have separate recordkeeping requirements.
Proposed paragraph (c) would require that the record be made by
either the certified person or by a person designated by the operator.
If the record is made by a person designated by the operator, the
certified person would be required to verify the record by initials and
date by or at the end of the shift for which the examination was made.
The record would be countersigned by the mine foreman and by the mine
superintendent, mine manager, or other mine official to whom the mine
foreman is directly accountable. The record would be made in a state-
approved book or in a bound book with sequential machine-numbered
pages.
Proposed paragraph (d) would require that the record be retained at
a surface location at the mine for at least one year and be made
available for inspection by authorized representatives of the Secretary
and the representative of miners.
Under the existing rule, the recordkeeping requirement for on-shift
examinations was included in paragraph (g) of Sec. 75.362 and the
requirement for retention was in paragraph (h). Under the proposal,
paragraphs (g) and (h) are removed from Sec. 75.362 and transferred to
paragraphs (c) and (d) of Sec. 75.363. As the requirement would remain
the same, there would be no change in the paperwork burden associated
with the recordkeeping for on-shift examinations. However, this
recordkeeping requirement would be new for hazardous conditions found
during supplemental examinations and at times when an on-shift
examination would not be required. This recordkeeping requirement would
also be new for hazardous conditions found during the examination
following a main mine fan stoppage of 15 minutes or longer (75.313).
MSHA estimates that a record of hazardous conditions found during
supplemental examinations would be made about 24 times a year at each
large mine and about 4 times a year at each small mine. MSHA further
estimates that it would take about 5 minutes to complete a record and
an additional 7 minutes for the certified person to initial and the
mine foreman and mine superintendent to countersign the record. The
total estimated recordkeeping burden for all affected mines would be
4,092 hours, of which large mines would incur 3,514 hours and small
mines would incur 578 hours.
In addition, MSHA estimates that a record of hazardous conditions
found during an examination following a main mine fan stoppage of 15
minutes or longer would be made about 100 times a year at large mines
and 100 times a year at small mines. MSHA further estimates that it
would take about 5 minutes to complete a record and an additional 4
minutes for the mine foreman and mine superintendent to countersign the
record. The total estimated recordkeeping burden for all affected mines
would be 28 hours, of which large mines would incur 14 hours and small
mines would incur 14 hours.
Proposed Sec. 75.364(b) would require an examination for hazardous
conditions and for noncompliance with mandatory safety or health
standards that could result in a hazardous condition to be made weekly
by a certified person.
Proposed paragraph (h) would require that at the completion of any
shift during which a portion of a weekly examination is conducted a
record be made of the results of each weekly examination, including a
record of hazardous conditions, their locations found by the examiner
during each examination, the corrective action taken, and the results
and location of air and methane measurements. The record would be made
by the person making the examination or a person designated by the
operator. If made by a person other than the examiner, the examiner
would be required to verify the record by initials and date. The record
would be countersigned by the mine foreman and by the mine
superintendent, mine manager, or other mine official to whom the mine
foreman is directly accountable. The record would be made in a state-
approved book or in a bound book with sequential machine-numbered
pages.
MSHA estimates that it would take about 2 minutes for the mine
superintendent to countersign the record and an additional 3 minutes to
record noncompliance with mandatory safety or health standards that
could result in a hazardous condition. The total estimated
recordkeeping burden for all affected mines would be 5,457 hours, of
which large mines would incur 3,048 hours and small mines would incur
2,409 hours.
Existing Sec. 75.382(c) requires mechanical escape facilities,
including automatic elevators, to be examined weekly.
Proposed paragraph (h) would require that a record of the results
of the examination of mechanical escape facilities, including any
deficiency found and the corrective action taken, be made at the
completion of any shift during which the weekly examination is made.
The record would be made by the person making the examination. The
record would be countersigned by the mine foreman and by the mine
superintendent, mine manager, or other mine official to whom the mine
foreman is directly accountable. The record would be made in a state-
approved book or in a bound book with sequential machine-numbered
pages.
Proposed paragraph (i) would require that the records be retained
for at least one year at a surface location at the mine and made
available for inspection by authorized representatives of the Secretary
and representative of miners.
A record of examinations would be required to be made weekly at all
mines that would be governed by Sec. 75.382. MSHA estimates that it
would take about 5 minutes to complete a record and an additional 4
minutes for the mine foreman and mine superintendent to countersign the
record. The total estimated recordkeeping burden for all affected mines
would be 3,360 hours, of which large mines would incur 3,300 hours and
small mines would incur 60 hours.
Send comments regarding these burden estimates or any other aspect
of this collection of information, including suggestions for reducing
these burdens, to Patricia W. Silvey, Director, Office of Standards,
Regulations and Variances, MSHA, room 631, Ballston Tower #3, 4015
Wilson Boulevard, Arlington, Virginia 22203, and directly to the Office
of Information and Regulatory Affairs, Office of Management and Budget,
Attention: Steve Semenuk, Desk Officer for MSHA, room 3001, New
Executive Office Building, Washington DC 20503.

New Technology for Recordkeeping

As the complexity of mining increases with the introduction of
technological improvements and innovations, MSHA foresees that
electronic storage of records in computer systems could enhance health
and safety by facilitating rapid access to critical information by
individuals with the authority and responsibility to direct or redirect
resources to correct potentially unsafe or unhealthy conditions.
Records electronically stored also could facilitate trend analysis,
allowing for earlier detection and correction of potential hazards. In
addition, the efficiency of accessing various records at a desktop
computer workstation could promote a more integrated and effective
approach to mine safety and health.
MSHA is considering allowing electronic storage of the records and
certifications required by this proposed rule. Although the Agency
envisions that such storage would most likely be on a personal computer
at the mine site, central storage of the records would not be precluded
as long as immediate access to those records at the mine site were
available. The use of electronic media for storage of such records
would have to be accessible, secure, verifiable, and provide for
necessary backups. MSHA would require both the availability of
immediate screen viewing of the information and the availability of a
hard copy printout within 1 hour of a request by MSHA or an authorized
representative of miners. The records would have to be kept in a secure
manner that would preclude alteration once the required information is
correctly entered. MSHA would have to be able to verify that the
electronic signature of the persons required to sign or countersign
such records is authentic and entered in a timely manner. Finally, the
records would have to be periodically backed-up on media separate from
the computer so that computer failure would not result in the loss of
data. Although MSHA has not specifically included any such provisions
in this proposal, the Agency requests comments on the storage of
records on electronic media, in particular on the safeguards necessary
to ensure the integrity of such storage.

II. Background

The Mine Safety and Health Administration (MSHA) is proposing to
revise the definition of return air in Sec. 75.301, and would revise
Secs. 75.310(a)(3), (a)(4) and (c), 75.311(d), 75.312(a), (b)(1), (c),
(d), (g)(1), (g)(3), (g)(4) and (h), 75.313(c)(2), (c)(3), (d)(1)(i),
(d)(1)(ii) and (d)(2), 75.321(a), 75.323(b)(1)(ii), (c)(1), and
(d)(2)(i), 75,333(a), (b)(1), (b)(3), (b)(4) and (e)(1), 75.334(e),
75.340(a), 75.342(a)(4), 75.344(a)(1), 75.360(a), introductory text to
(b), (b)(1), (b)(3), (b)(4), (b)(6), introductory text to (c), (c)(1),
introductory text to (c)(3) and (f), 75.362(a)(1), (c)(1), (d)(1)(iii),
and (d)(2), 75.364(a), (b) and (h), 75.370(a)(3), (c)(1), and (f),
75.371(b), (s), (z) and (bb), 75.372(b)(3), 75.380(d)(3), (d)(4)(ii),
(d)(5), (f) and (i)(2) of its existing safety standards for ventilation
of underground coal mines. MSHA is also proposing to redesignate
Sec. 75.312(f) as (f)(1), and paragraphs (g)(2) and (g)(3) as (g)(3)
and (g)(4). Section 75.344(b)(2) would be redesignated as
Sec. 75.344(b)(3). Existing Sec. 75.360(e) would be removed and (f)
through (h) would be redesignated as (e) through (g). Existing
Sec. 75.362(a)(2), (g) and (h) would be removed and (d)(1)(i) and
(d)(1)(ii) would be redesignated as (d)(1)(ii) and (d)(1)(iii).
Existing Sec. 75.370(b)(1) through (f) would be redesignated as (c)(1)
through (g). MSHA is further proposing to add new Secs. 75.312(f)(2),
(g)(2), and (g)(5), 75.320(e), 75.330(c), 75.333(h), 75.344(b)(2) and
(e), 75.360(b)(8) through (b)(10), 75.362(a)(2), (d)(1)(i) and (g),
75.363, 75.370(b), 75.372(b)(19) and (b)(20), 75.380(d)(4)(iii),
75.380(f)(2) and (f)(6) and 75.382(g), (h) and (i). New introductory
text would be added to Sec. 75.388(c), and new introductory text would
be added to Sec. 75.389(c). These revisions are proposed in accordance
with section 101 of the Federal Mine Safety and Health Act of 1977, 30
U.S.C. 811.
On May 15, 1992, MSHA published a notice in the Federal Register
revising its safety standards for ventilation of underground coal mines
(57 FR 20868). To assure that mine operators could effectively plan and
implement necessary changes, MSHA delayed the effective date of the
final rule from August 16, 1992, to November 16, 1992 (57 FR 34683).
Through discussions with the mining community, the Agency became
aware of potential problems that could arise through the implementation
of Secs. 75.344(a)(1) and 75.313. MSHA therefore initially stayed these
two provisions until July 1, 1993, (57 FR 53856) extended the stay
until July 1, 1994 (58 FR 31908), and has extended the stay until the
completion of this rulemaking (59 FR 18485). Sections 75.314, 75.315
and 75.345 are in effect during the duration of the stay. As proposed,
Sec. 75.313 would revise paragraphs (c)(2), (c)(3), (d)(1)(i),
(d)(1)(ii) and (d)(2) of stayed Sec. 75.313 and delete interim
Secs. 75.314 and 75.315. Also as proposed, Sec. 75.344(a)(1) would
revise stayed Sec. 75.344(a)(1) and delete interim Sec. 75.345. Section
75.344(a)(1) was stayed to determine whether requiring all compressors
to be located in a noncombustible structure or area could create a fire
hazard due to overheating.
Section 75.313 was stayed to further consider the effect of fan
stoppages in certain mines. As written, the standard would have allowed
circuits and equipment used to withdraw persons from the mine to remain
energized until the persons are withdrawn. The Agency is concerned that
under some conditions methane could migrate into haulageways after a
fan stoppage. This could result in a hazard if all underground
electrical circuits are not promptly deenergized and all mechanized
equipment is not shut off.
On November 16, 1992, the United States Court of Appeals for the
District of Columbia Circuit (D.C. Circuit) issued an order staying the
application of the air quality standards for oxygen and carbon dioxide
at 30 CFR 75.321(a). MSHA is continuing to litigate this application of
the standard. However, in conformance with the Court's order, the
Agency has suspended indefinitely Sec. 75.321(a) and redesignated the
first sentence of previous Sec. 75.301 to remain in effect as
Sec. 75.321(c) (57 FR 55457, November 25, 1992). The result is that,
with the exception of bleeder systems and worked-out areas, the Agency
is continuing to apply the oxygen and carbon dioxide limits to all
areas where persons work or travel as in previous Sec. 75.301. As
proposed, Sec. 75.321(a) would revise suspended Sec. 75.321(a) and
delete interim Sec. 75.321(c).

III. Discussion of the Proposed Rule

A. General Discussion

Underground coal mine ventilation affects various aspects of the
safety and health of miners. Proper underground coal mine ventilation
is necessary to protect against mine fires and explosions due in part
to the presence of explosive gases, oxygen-deficient atmospheres, and
accumulations of other harmful gases and float coal dust. Ventilation
is also a primary method of controlling miners' exposure to respirable
dust and preventing the development of pneumoconiosis (black lung). In
enacting the statutory ventilation standards of the Mine Act, Congress
expressly recognized these and related dangers associated with
inadequate ventilation:

[V]entilation of a mine is important not only to provide fresh
air to miners, and to control dust accumulation, but also to sweep
away liberated methane before it can reach the range where the gas
could become explosive. In terms then of the safety of miners, the
requirement that a mine be adequately ventilated becomes one of the
more important safety standards under the * * * Act.

S. Rep. No. 181, 95th Cong. 1st Sess. 41 (1977), reprinted in Senate
Subcommittee on Labor, Committee on Human Resources, 95th Cong., 2d
Sess., Legislative History of the Federal Mine Safety and Health Act of
1977, at 629 (1978).
On May 15, 1992, the Agency published a comprehensive revision of
its ventilation standards for underground coal mines. Because of the
scope and extensive coverage of the new standards, the Agency held a
series of informational meetings across the country to brief the mining
public on the provisions of the new rule. As a result of these meetings
and other comments received by the Agency at meetings with industry and
labor groups relative to the ongoing litigation, as well as its own
review of the application of the regulations, MSHA became aware of
several provisions that needed to be further evaluated and analyzed. In
many cases, comments received were verbal. Therefore, any references in
this preamble to ``comments'' or ``commenters'' do not necessarily mean
either written or formal comments. Persons wishing to formalize
comments made during public meetings or other meetings with the Agency
should submit their comments as a part of this rulemaking.
In general, the proposed standards specified below address the
stayed provisions, clarify the Agency's intent, refine the application
of the rule in light of information received, and more fully address
the recognized precautions and procedures necessary to avoid hazards
associated with improper ventilation of underground coal mines. Major
areas addressed include: examinations, including preshift examinations;
recordkeeping and certification; involvement of the representative of
miners in the plan approval process; escapeway dimensions; equipment in
primary escapeways and fire suppression systems. These standards are
intended to fit within the comprehensive structure of the ventilation
rule now in effect.
In addition, a segment of the mining community has asserted that
certain provisions concerning the installation and removal of
mechanized mining equipment were promulgated without the benefit of
adequate comment. The Agency disagrees. The September 1989 explosion at
the William Station Mine in Kentucky demonstrates, however, that proper
ventilation during the installation and removal of mechanized mining
equipment is essential and can greatly enhance the protection provided
to miners in these areas. Therefore, for the purpose of receiving and
giving full consideration to all pertinent comments on this issue, MSHA
is reproposing each provision that addresses the installation and
removal of mechanized mining equipment, and is soliciting comments for
each. The section-by-section portion of the preamble discusses each
provision affected and the proposed rule sets out the reproposed
language.
Since publication of the ventilation rule, the Agency has received
comments stating that Atmospheric Monitoring Systems (AMS) should be
permitted to operate by battery backup during fan stoppages and not be
required to be intrinsically safe. The commenters indicated that the
information thus provided by the AMS would assist the operator in
obtaining information regarding the underground conditions of the mine.
To allow the battery backups would require a revision of
Secs. 75.311(h) and 75.313(e). The Agency solicits comments on the
merits and the effect on safety of allowing battery backups and
conditions, such as low methane levels, that must exist if they are
permitted to be used.
Also, since publication of Sec. 75.383, the Agency has received
comments suggesting that older miners be allowed to individually
decline participation in escapeway drills. The Agency is not proposing
any revision to Sec. 75.383; however, comments are solicited as to the
appropriateness of providing an option which would allow miners to
individually ``opt out'' of escapeway drills, and the circumstances
under which miners would be permitted to ``opt out.''
The Agency solicits comments on the specific provisions addressed
in this proposal. Comments received that also address other provisions
will be considered to the extent that they address the issues relevant
to this proposal.

B. Section-by-Section Discussion

Section 75.301 Definitions
Since the final rule became effective on November 16, 1992, it has
come to the attention of the Agency that the Sec. 75.301 definitions of
intake and return air are being interpreted in a manner not wholly
consistent with the original intent. Under the proposal, the definition
of return air would be modified to more clearly convey the intended
meaning.
Instances have developed where operators desire to take air from an
intake air course to ventilate shops, electrical installations, or for
other purposes, and this air is then coursed directly to the surface
and is not used to ventilate working places. Under one reading of the
existing definition, because this air has not ventilated a working
place or a worked-out area, the air in this air course cannot be
considered return air. Therefore, a violation could exist in that the
air ventilating the shop, compressor, or electrical installation was
coursed into an intake rather than into a return as required. This was
not the intent of the Agency and no safety benefit is associated with
such a result.
Under the proposal, the definition of return air would be modified
to permit operators to designate certain air courses as return air
courses for the purpose of ventilating structures, areas or
installations that are required to be ventilated to return air courses
and for ventilating seals when this air will not be used to ventilate
working places. Thus, an operator wishing to split air off of an intake
for the purpose of ventilating shops, electrical installations, or for
other purposes, could designate the air course into which the split is
directed as a return provided the air in the air course would not used
to ventilate working places or other locations, structures,
installations or areas required to be ventilated with intake air.
The Agency does not intend that operators routinely redesignate air
courses from intake to return. Should questions arise as to the need to
redesignate an intake as a return, MSHA will be available for
consultation. Additionally, in order that all interested parties are
made aware of the redesignation, MSHA is proposing to require in
Sec. 75.372, Mine ventilation map, that air courses that are
redesignated from intake to return for the purposes discussed above be
shown on the mine ventilation map.
Section 75.310 Installation of Main Mine Fans
Main mine fans provide the means by which mechanically produced
pressure is supplied to the mine ventilating current. The Agency is
proposing to revise paragraphs (a)(3), (a)(4) and (c) of Sec. 75.310.
The existing standard requires, in part, that each main mine fan be
installed on the surface in an incombustible housing and be connected
to the mine opening with incombustible air ducts. Paragraph (a)(3) of
existing Sec. 75.310 requires that each main mine fan be equipped with
an automatic device that gives a signal when the fan either slows or
stops. The signal from this device is to be placed so it can be seen or
heard by a responsible person who has been designated by the operator
and who is always on duty when persons are underground.
During informational meetings held with the mining community, it
was suggested to the Agency that the standard should be clarified in
two respects. First, it was stated that the provision was not clear as
to whether the signal must automatically be given at a surface location
at the mine. Second, the Agency was asked to clarify whether a fan
monitoring system used in lieu of a circular pressure recorder to
monitor fan pressure must generate a continuous graph or chart.
To address the first of these concerns, proposed paragraph (a)(3)
specifically would require the signal to be given at a surface location
at the mine where it could be seen or heard by a responsible person
designated by the operator who is always on duty when persons are
underground. Under the proposal, two-way communication with working
sections would continue to be required. The requirement would be
extended to include established locations where persons are normally
assigned to work, such as belt transfer points and shops. This
requirement is consistent with existing Subpart Q--Communications, but
may require the installation of a limited number of mine phones at
locations off the section. Many of these locations are routinely
equipped with two-way communication even though it is not required by
the existing standard. It is not intended that this communications
capability be provided in areas where persons are assigned to work
temporarily, such as areas where secondary roof support is being
installed or where rock dust is being applied. The requirement that
two-way communication be provided to locations where persons are
normally assigned to work is intended to assure that these persons
receive prompt notification of fan stoppages. Because these work
locations are off the section, a lack of communication capabilities
could result in delays in notification and therefore delays in
withdrawal. The requirement that the signal be given at a surface
location at the mine is not intended to preclude the signal from also
being given elsewhere, such as at a central office, as long as it is
given at the mine as previously discussed.
The existing rule requires that each main mine fan be equipped with
a pressure recording device or a main mine fan monitoring system.
Traditionally, the instrument of choice for recording fan operating
pressure has been the mechanical, circular pressure recorder. As the
name implies, this device generates a record of the fan pressure. This
record is generated continuously as a chart that is replaced weekly.
Paragraph (a)(4) of the existing rule specifically refers to the use of
a fan monitoring system as an alternative to the pressure recorder. The
proposal eliminates this reference since other means of continuously
monitoring the fan pressure and providing a record may be acceptable.
Relatively recent advances in technology have permitted the measurement
and recording through other means. This proposed provision would permit
the use of this technology for monitoring main mine fan pressure,
provided, as proposed in paragraph (a)(4), that a continuous record of
the pressure is maintained. The proposal would require that when a
pressure monitoring device is used in lieu of a pressure recording
device, it produce a continuous graph or chart of the fan pressure. A
hard copy of the continuous graph or chart would be printed at regular
intervals of not more than 7 days. The generated graph or chart would
be required to correlate fan pressure to the time and date. The term
``continuous'' refers to the frequency with which the device polls the
fan pressure to obtain the data. It is the Agency's understanding that
typical polling frequency is on the order of a few seconds. MSHA is
soliciting comments as to an appropriate polling frequency that would
provide a record that is substantially continuous.
Records of the fan pressure generated by a pressure monitoring
device would be maintained in accordance with existing Sec. 75.312(h).
That is, the records would be maintained at a surface location at the
mine for at least one year and would be made available for inspection
by authorized representatives of the Secretary and the representative
of miners.
In addition to permitting fan monitoring systems to be used as a
means of recording fan pressure, the existing rule permits the use of
other devices for measuring fan pressure under certain circumstances.
This exception is for mines permitted to shut down main mine fans as
approved in the ventilation plan. As explained more fully in the
preamble for Sec. 75.310(a)(4) of the existing rule, this provision
provides a compliance alternative for small mines that normally operate
only one shift a day and do not have sealed or unsealed worked-out
areas. For these mines, the existing rule allows the use of a pressure
measuring device if the use of the device is approved in the
ventilation plan for the mine. The proposal would continue this
practice.
Paragraph (c) of the existing rule specifies the minimum
requirements for a fan monitoring system, including the parameters that
a fan monitoring system must monitor if it is to be used in lieu of the
daily fan check required by Sec. 75.312. The Agency continues to
support the use of these systems or any other technology effective in
enhancing safety but believes, based on comments received, that the
additional requirements relative to the use of these systems are
warranted. Specifically, commenters suggested that the information
generated by fan monitoring systems be provided at a surface location
at the mine where a responsible person is always on duty when persons
are underground and that this information be reviewed by mine
management. The Agency agrees with these suggestions and proposes in
paragraph (c) to require that when a fan monitoring system is used in
lieu of the daily fan examination required by Sec. 75.312 the
monitoring system would be required to have the capability of
providing, on demand, a printout of the information being monitored.
This capability is intended to facilitate the review of the information
by mine management required in Sec. 75.312(b).
Additionally, the proposal would require in paragraph (c)(5) that
the fan monitoring system provide monitoring, records, printouts, and
signals at a surface location at the mine where a responsible person
designated by the operator is always on duty and where signals from the
monitoring system can be seen or heard while anyone is underground. For
the purpose of the standard, a responsible person would be one who
receives the signal and makes proper notification. As with the
requirement that fan stoppage signals be given at a surface location at
the mine, this proposed requirement is not intended to preclude the
data from the fan monitoring system from also being provided elsewhere
as long as it is provided at the surface location at the mine. Also, as
with the requirement for two-way communication at the location where
fan stoppage signals are monitored, the proposal would require in
paragraph (c)(5) that the person at the designated surface location
have two-way communication with working sections and would extend the
requirement to established locations where persons are normally
assigned to work, such as belt transfer points and shops. This
requirement is consistent with existing Subpart Q--Communications, but
may require the installation of a limited number of mine phones at
locations off the section. Many of these locations are routinely
equipped with two-way communication even though it is not required by
the existing standard. It is not intended that this communications
capability be provided in areas where persons are assigned to work
temporarily, such as areas where secondary roof support is being
installed or where rock dust is being applied.
Section 75.311 Main Mine Fan Operation
The Agency has received comments that notification of mine
management officials, having sufficient authority to initiate
corrective actions is needed to assure that repairs are undertaken and
to assure continued reliable ventilation of the mine. Paragraph (d)
would be revised to provide for immediate notification of the mine
superintendent, assistant mine superintendent, or mine foreman if any
unusual variance in the mine ventilation pressure is observed, or if an
electrical or mechanical deficiency of a main fan is detected. The
standard would require appropriate action or repairs to be instituted
promptly. The Agency would expect that any necessary arrangements for
repair personnel and replacement parts would be promptly completed,
once the problem or need for repair was identified. One of the actions
appropriate to an unusual variance in pressure would be an immediate
investigation into the cause. Notification of mine management is
intended to assure that the appropriate actions are taken and that any
necessary repairs are completed as soon as possible. Both the
requirement for notification of mine management and the requirement for
prompt initiation of corrective actions were included in the previous
regulation. Although no change was intended, it was suggested that
these requirements be reinstated so as to eliminate any possible
confusion that might exist. After reconsideration, the Agency agrees
that the existing standard could be interpreted contrary to the intent
and therefore, is proposing the changes discussed. Since the current
ventilation standards became effective on November 16, 1992, questions
have arisen concerning the operation of back-up fans. The following
discussion is intended to address the questions received by the Agency.
When a back-up fan operates in place of the main mine fan, the
back-up fan is considered to be a main mine fan and all subpart D
requirements for main mine fans are applicable. These requirements
include: the installation requirements of Sec. 75.310, the operation
requirements in this Sec. 75.311, the examination and recordkeeping
requirements of Sec. 75.312, and, the unintentional fan stoppage
requirements of Sec. 75.313, which would apply should a back-up fan
fail while persons are underground.
A typical back-up fan application is where a back-up fan producing
an air quantity comparable to the main mine fan is substituted upon the
unintentional failure of the main mine fan. Section 75.313 would
require withdrawal of the miners if the backup fan, or main mine fan,
is not started within 15 minutes. If the back-up fan is started within
15 minutes, however, normal work may resume after an examination, since
the air quantity would be provided. An example would be two identical
fans at a shaft where one operates as the main mine fan while the other
is available to back up the main mine fan. Typically, the usage of
these fans is alternated.
Another possible application is a back-up fan producing a lesser
quantity than the main mine fan. In this case, unless the main mine fan
can be restored to operation within 15 minutes, withdrawal would be
required under Sec. 75.313. After withdrawal is complete, re-entry
could be permitted and electrical circuits restored as provided through
the approved ventilation plan. The Agency would expect operators to
rely on engineering data or actual ventilation survey results when
developing these ventilation plan provisions. During operation of the
back-up fan, the approved ventilation plan would only permit activity
which is related to maintaining the mine in safe condition. This work
could include pumping, urgent roof support installation, or other
safety-related work. The production of coal under these conditions
would not be permitted unless the mine were adequately ventilated and a
new ventilation plan has been approved.
Some multiple-fan ventilation systems are configured such that if
one fan fails, reduced air quantities continue to ventilate all
portions of the mine with no potentially hazardous air reversals
occurring. In such cases, ventilation plan provisions, if supported by
data, could be developed which would allow re-entry for the purposes
discussed in the previous paragraph. This activity would be limited to
maintaining the mine in safe condition until the full ventilation
system is restored to operation.
Under existing Sec. 75.311(b)(1), when a main mine fan is stopped
intentionally and the ventilating quantity of the main mine fan is not
maintained by a back-up fan, only persons necessary to evaluate the
effect of the fan stoppage or restart, or to perform maintenance or
repair work that cannot otherwise be made while the fan is operating,
are permitted underground. The maintenance or repair work which could
not be made while the fan is operating is limited to work or repair
which would endanger the safety of the worker if the fan were
operating. Examples of the type of work that may not be possible while
the fan is operating could include maintenance of the fan, repairs or
adjustments to ventilation controls immediately inby the fan that are
subject to high pressure differentials, and coating of mine surfaces
immediately inby the fan. These examples are given for the purpose of
facilitating understanding and are not considered all-inclusive.
While the Agency is proposing to change only paragraph (d) of
existing Sec. 75.311, comments are specifically solicited on the issues
discussed.
Section 75.312 Main Mine Fan Examinations and Records
The Agency would revise the existing standard in a number of
respects. Except in certain situations, a daily examination of the main
mine fans would be required each day that the mine operates. One
exception would be the use of a fan monitoring system in accordance
with Sec. 75.312. Requirements for training, recording of defects,
review of fan monitoring data, certifying and countersigning of records
would be added to the rule. Also, the standard would allow underground
power to remain energized when a fan is shut down for testing of the
automatic closing doors and fan signal device, provided that the fan is
restarted within 15 minutes, and would permit an alternative means of
testing that would not require stopping the fan.
Proper operation of main mine fans is critical to mine ventilation.
Paragraph (a) of the proposed rule, like the existing standard,
requires main mine fans and associated components, including devices
used to measure and record pressure, to be examined at least once each
day that the fan operates, unless a functioning fan monitoring system
is used. However, it is proposed that on any day when no one goes
underground that a fan examination would not be required. The Agency is
proposing this approach along with the provision that an examination of
the fan be completed prior to anyone's entering the mine, including
certified persons. Such an examination would assure that the fan is
operating properly. The Agency does not believe that any hazard can be
associated with not examining a mine fan if no one goes into the mine,
and solicits comments on this point.
During the informational meetings and later discussions, the Agency
was asked to clarify the qualifications of the person designated by the
operator to make daily fan examinations or the weekly fan examination
in the case of mines using fan monitoring systems. It continues to be
the position of the Agency that persons assigned to make this or any
other examination must be capable of making an adequate examination;
that is, an examination in a manner that assures the protection sought
by the standard. For this reason, and to address the concerns raised,
the proposal would adopt the words of the regulation in effect prior to
November 16, 1992, Sec. 75.300-4(a), and require in paragraphs (a) and
(b)(1) that main mine fans be examined by trained persons designated by
the operator. Since the purpose of the examination, as stated in the
proposed standard, is to assure the electrical and mechanical
reliability of the fan, the training that the examiner receives should
be focused on the electrical and mechanical functioning of fans.
The proposal, in paragraph (b)(1)(i), reflects comments received by
the Agency that in order for fan monitoring systems to be effective,
the data from these systems must be reviewed by mine management each
day. This review is intended to parallel the daily fan examination and
assure that responsible personnel are aware of the performance of the
fan and the fan monitoring system. In paragraph (b)(1)(ii), the
proposal would retain the requirement that at least once every 7 days
the monitoring system be tested and the main mine fan be examined.
Consistent with paragraph (a), as discussed previously, this
examination would be required to be done by a trained person designated
by the operator for the purpose of assuring the electrical and
mechanical reliability of the fan.
During the informational meetings and later discussions, the Agency
was also requested to clarify the application of paragraph (c) of this
standard. Some of the comments concerned whether underground electrical
circuits must be deenergized while tests of fan signal devices and
automatic closing doors are performed. Questions also arose as to
whether anyone could be in the mine during the tests and whether a
complete Sec. 75.360 preshift examination is required following the
tests before anyone could enter the mine.
The proposal clarifies the Agency's intent in paragraphs (c) and
(d) of the existing Sec. 75.312. The 31-day tests are to determine if
the alarm activates properly and, in multiple-fan systems, whether the
automatic doors, if required, close. Although fan stoppages for these
tests are normally of short duration, it must be recognized that on
rare occasions difficulty may be encountered in restarting the fans.
Therefore, the Agency has determined that it is not advisable to allow
miners underground during tests when the fan is stopped unless
concurrent activities are scheduled that are necessary to evaluate the
effect of the fan stoppage or restart, or to perform maintenance or
repair work that cannot otherwise be done while the fan is operating.
Another commenter continued to express concern that monthly
stoppage of fans for testing can cause undue stress on the fans. MSHA
has received assurances from fan manufacturers that stopping the fans
monthly to test the signal device will not cause undue stress on fans.
The Agency has also recently received assurances from motor
manufacturers that monthly stoppage of fans will not harm fan motors.
The Agency solicits comments on this issue as well as on any other
aspect of paragraphs (c) and (d).
The Agency has received requests for clarification as to whether
fans stopped for testing must be completely stopped during the 31-day
tests. The purpose of the standard is to assure proper operation of the
alarm and doors when a fan fails. Under certain conditions, such as
with a substantial natural ventilating pressure, the fan blades may
continue to rotate indefinitely. However, after power has been removed
and the fan is in the process of stopping, once the alarm sounds and
the doors close, the test has been successfully completed and the fan
may be restarted even though the fan blades may not have become
motionless.
Recognizing that the duration of these tests is normally short, the
proposal does not require underground electrical circuits to be
deenergized unless the fan cannot be restarted within 15 minutes or
unless persons are permitted underground in accordance with
Sec. 75.311(b)(1). In accordance with longstanding practice, as
indicated by a review of fan stoppage plans and consistent with
existing Sec. 75.313, an examination as described in Sec. 75.360 (b)
through (e) would be required if the fan is not restarted within 15
minutes. The Agency believes that after 15 minutes, additional action
is needed to protect miners from the hazards that may develop following
a fan stoppage.
Following publication of the existing standard, commenters
suggested that it may be possible to test the fan signals and the
automatic closing doors without shutting off the fans. If it is
possible to properly test the fan signal and automatic closing doors
without stopping the fan, then the Agency would permit such an
alternative. The Agency has become aware that such an approach is being
actively explored by at least one mining company. Therefore, in the
interest of allowing for advances in technology in this area, the
proposal would permit an alternative test that does not require
stopping the fan when the operator demonstrates that it provides the
same level of assurance that the automatic closing doors and fan
signals will function as intended during fan stoppages. Alternative
approaches to stopping the fan would be required to be approved in the
ventilation plan. The Agency would anticipate that any alternative
approach approved would retain the 31 day interval for demonstrating
that the automatic closing doors or fan signal will operate as
intended. The Agency solicits comments on this approach to fan tests.
Specifically, comments should address the method that should be used to
assure that the alternate test provides the same level of assurance
that the automatic closing doors and fan signals will function as
intended during fan stoppages.
Paragraph (f)(1) retains the requirement in the existing rule that
persons making main mine fan examinations certify by initials and date
at the fan or another location specified by the operator, that the
examinations were made, and that each certification identify the main
mine fan examined. Consistent with the practice of certifying that fan
examinations have been completed, the Agency is proposing a
certification requirement in paragraph (f)(2). The person completing
the review of the data from a fan monitoring system used in lieu of
daily fan examinations would certify that the review has been
completed. The manner of certification would be by initials and date on
the printout of the data from the system. To facilitate this
certification, proposed Sec. 75.310(c)(3), as discussed previously,
would require that the fan monitoring system be capable of providing,
on demand, a printout of the data.
Proposed paragraphs (g)(1) through (g)(5) would set out the
requirements for recordkeeping and countersigning of main mine fan
examination records. Paragraph (g)(1) would require that by the end of
the shift on which the examination is made, persons making main mine
fan examinations would record all defects found during the examination
that may affect the operation of the fan. Unlike the previous standard,
the existing standard requires that only defects that are not corrected
by the end of the shift be recorded. The preamble to the existing rule
explains this approach as follows: ``* * * since the main purpose of
this recordkeeping requirement is to alert miners on oncoming shifts of
defects found during the fan examination that may affect their shifts,
it serves no additional safety benefit to require a record to be made
of deficiencies which are corrected by the end of the shift on which
the examination is made.'' However, following publication of the
standards, the Agency received comments that records of defects,
corrected or not, serve to indicate recurring problems with mine fans.
Upon reconsideration, MSHA agrees that recurring problems found during
main mine fan examinations may be indicative of more serious defects
and if mine management is not made aware of these problems through the
maintenance of records they could ultimately lead to a fan failure.
Therefore, similar to the previous standard, the proposal would require
that all defects found during the daily fan examination be recorded. As
with other proposed provisions of the rule, records required in
paragraphs (g)(1) through (g)(4) would be made in a state-approved book
or in a bound book with sequential machine-numbered pages. Comments are
specifically solicited on this approach and on an alternative approach
wherein the Agency would develop, in coordination with the states,
books specific for the required records.
Since promulgation of the current regulation, the Agency has become
aware of some potential difficulties in reviewing records and data
generated by fan monitoring systems and atmospheric monitoring systems.
The problem involves the commingling of this information with other
information, such as production or operations-related data produced by
the computer systems of which they are a part. Since the physical
volume of production, operations, and other data may be considerable,
safety-related data may not be readily accessible which may discourage
the regular review and proper use of the information. A possible
solution is to require that all safety related data be printed on a
dedicated printer. The Agency is not proposing this solution at this
time but rather is soliciting comments on possible alternative
solutions. At this time, the Agency is proposing, in paragraph
(g)(2)(i), that the certified copies of data required by paragraph
(f)(2) be maintained separate from other computer generated reports or
data in order to facilitate the review of this data by the operator,
the representative of miners, and the Agency.
Proposed paragraph (g)(2)(ii) would require a record to be made of
any fan monitoring system malfunctions, electrical or mechanical
deficiencies in the monitoring system and any sudden increase or loss
in mine ventilating pressure. The records would be used to identify
chronic or recurring problems with the system that could indicate the
need for repairs, replacement of parts, or upgrades in hardware or
software in order to keep the system functioning in a reliable manner.
The record would be required to be made by the end of the shift on
which the review of the data is completed. This requirement would help
to assure that records are current and that potential problems are
identified in a timely manner.
Consistent with existing requirements, paragraph (g)(3) would
require that at mines permitted to shut down main mine fans under
Sec. 75.311, if a pressure recording device is not used, a record be
made of the time and fan pressure immediately before the fan is
stopped, and after the fan is restarted and the fan pressure
stabilizes. A record of these pressures at both shutdown and restart
would help identify any adverse change in ventilation that may have
occurred during the fan stoppage.
Paragraph (g)(4) would require that a record of the results of the
tests be made by the end of the shift on which the monthly test of the
automatic fan signal device or the automatic closing doors is
completed. This requirement would help to assure that potential
problems are identified in a timely manner so that proper operation of
the automatic fan signal device and the automatic closing doors can be
maintained.
Paragraph (g)(5) would require that the records required under
paragraphs (g)(1) through (4) be countersigned by the mine foreman by
the end of the mine foreman's next regularly scheduled working shift.
During an absence of the mine foreman, the person acting as mine
foreman would countersign. The Agency intends that the mine foreman,
the person most responsible for the day-to-day operation of the mine,
be notified of the information contained in the reports. Allowing until
the end of the mine foreman's next regularly scheduled working shift to
countersign the report would assure that the mine foreman is aware of
the results of the examination and would enable corrective actions to
be taken.
The proposal would also require that within two scheduled
production days after the mine foreman has countersigned, the record of
the examination be countersigned by the mine superintendent, mine
manager, or other mine official to whom the mine foreman is directly
accountable. The intent of the proposal is to assure that a higher
level official, empowered to redirect resources, be aware of any
condition requiring corrective actions. Since this second level
official may not be physically located at the mine on a full-time
basis, two scheduled production days are proposed as a reasonable
period of time for countersigning.
Section 75.313 Main Mine Fan Stoppage With Persons Underground
This standard establishes safety precautions for any unplanned main
mine fan stoppage that interrupts ventilation while persons are
underground. Paragraph (a)(3) requires all persons to be withdrawn from
working sections and areas where mechanized mining equipment is being
installed or removed when ventilation is interrupted by a main mine fan
stoppage. Areas where coal is being extracted or mechanized mining
equipment is being installed or removed are typically the places in an
underground mine where methane accumulation and other hazards to health
or safety can develop quickly when ventilation is interrupted. To avoid
exposure of miners to these hazards, timely withdrawal of persons is an
important safety practice. Although the Agency believes that the
promulgation of paragraph (a)(3) of this standard was done
appropriately, it is being reproposed for the purpose of receiving and
giving consideration to all pertinent comments.
Concerns have been raised about the possibility of methane
migration following fan stoppage, and the danger of using electrical
power to withdraw miners should this occur.
The proposal would revise stayed Sec. 75.313(c)(2) and (c)(3) which
address deenergization of electric power circuits and shutting-off of
mechanized equipment not located on working sections. It also would
revise paragraph (d)(1)(i) and (ii) and (d)(2) which deal with
examination of the mine before miners can return when power is
restored. The Agency is not proposing a revision of paragraphs (a),
(b), (c)(1), and (e) at this time. These paragraphs of stayed
Sec. 75.313 would remain unchanged from the stayed provision.
Under paragraph (c)(2) of the proposal, underground electrical
circuits must be deenergized, except those circuits necessary for
withdrawal if such circuits are located in areas and haulageways where
methane is not likely to migrate into or accumulate. The remaining
energized circuits would be deenergized as persons are withdrawn. The
Agency recognizes that in a limited number of mines methane may migrate
from adjacent areas and enter travelways or haulageways used by miners
for withdrawal. Under these conditions, permitting power circuits to
remain energized may increase the potential for a methane ignition. The
determination of the likelihood of methane migrating into haulageways
can be made through underground tests or computer simulations of
ventilation systems. It is the intention of the Agency that when it is
determined that methane is likely to accumulate or migrate into an
area, electrical circuits used for transportation would not be
permitted to remain energized and persons would not be permitted to
ride out of the mine in the event of a fan stoppage. The Agency would
expect the operator to provide the necessary data from which a
determination can be made. For the same reasons, paragraph (c)(3) of
the proposal would require mechanized equipment not located on working
sections to be shut off unless the equipment is necessary to withdraw
persons from the mine and is located in areas where methane migration
or accumulation is unlikely to occur. The Agency solicits comments on
the appropriateness of this type of mine-specific evaluation that
balances the expeditious withdrawal of miners against the potential for
methane accumulations.
Under paragraphs (d)(1)(i) and (ii) of the proposal, the Agency is
clarifying that when ventilation is restored and before electrical
circuits are energized or nonpermissible mechanized equipment is
started, no one other than designated certified examiners would be
permitted to enter or reenter any underground area of the mine until an
examination is conducted as described in Sec. 75.360(b) through (e) and
the area is determined to be safe. This would prohibit nonpermissible
mechanized equipment from being started until an examination is
completed. However, permissible equipment may be used to facilitate the
examination required by the proposal. The Agency recognizes that it may
not be possible for examiners to enter the mine without some power
being restored in shafts or slopes to power elevators, hoists, or other
mechanical facilities operated in the shaft or slope. The Agency does
not intend to prohibit these facilities from being energized when used
to facilitate the examination, provided they are in intake air and the
power is limited to the shaft or slope in which they operate. The
Agency solicits comments on this approach to fan stoppages.
This examination would not be equivalent to a full-scale preshift
examination in that (1) a preshift is conducted within 3 hours
preceding the beginning of the shift, and (2) the recordkeeping
requirements of Sec. 75.360 would not apply for the examination
following a fan stoppage. However, in accordance with proposed
Sec. 75.363, a record of all hazardous conditions found would be
required. This type of examination is an accepted safety practice in
the industry. It is a primary means for determining the effectiveness
of a mine's ventilation system and of detecting hazards such as methane
accumulations that may be present in travelways or other areas where
miners may work after an interruption of ventilation. After a fan is
restarted, the examination will determine if the air is moving in its
proper direction and at its normal volume.
The Agency has reconsidered its position in stayed
Sec. 75.313(d)(2) and proposed in paragraph (d)(2) to specifically
require miners, other than designated certified examiners, to continue
to the surface should the fan restart during withdrawal. A commenter
has maintained that following a fan stoppage, a hazard could occur due
to methane accumulations, and therefore miners should not be permitted
to remain underground. MSHA agrees that such methane accumulations
could occur, but believes that any risk of ignition would be
significantly reduced by the requirement that mechanized equipment be
shut off and electrical power circuits deenergized except for equipment
and power circuits necessary for withdrawal if located in areas or
haulageways where methane is not likely to migrate to or accumulate.
Under stayed Sec. 75.313, the equipment or circuits used for withdrawal
must be shut off or deenergized as persons are withdrawn. However, to
provide an added margin of safety, MSHA is proposing withdrawal of all
miners to the surface except designated certified examiners who may
begin the examination required before miners return to underground
areas. The Agency specifically solicits comments on this issue.
This commenter further stated that when a fan is down for an
extended period of time, a fan should not be restarted until miners
safely reach the surface. However, as stated in the preamble to the
existing rule, MSHA believes that the fan should be restarted as soon
as possible to reestablish proper ventilation and to remove the
potential for methane accumulations. The Agency solicits comments on
the pros and cons of reestablishing ventilation by restarting a mine
fan during evacuation, and on having miners continue to the surface
should a fan restart during withdrawal.
Additionally, the proposal would require that an examination be
made as described in Sec. 75.360(b) through (e). Although complete
withdrawal of miners is required, this examination could begin once
ventilation has been restored and would be performed by certified
persons designated by the operator to conduct the examination. The
Agency is proposing this approach because of the safety concerns
associated with extended interruptions in the ventilation system. It is
recognized that under Sec. 75.360(a) a preshift examination can be made
for an oncoming shift while miners are underground. However, the
proposal would not allow miners to remain underground because of the
lack of ventilation compared to the situation where ventilation is
continuously maintained.
Section 75.320 Air Quality Detectors and Measurement Devices
The informational meetings and later discussions on the rule
indicated that simply requiring detectors for measuring methane and
oxygen deficiency to be maintained in permissible condition does not
completely satisfy the need for assuring proper maintenance. It was
suggested that without a requirement for maintenance to be done by a
trained person, similar to that which existed in the previous standard,
a person with less than the necessary understanding of the instrument
and the permissibility requirements might be assigned the task. The
proposal would require that methane detectors and other devices be
properly maintained at all times and, to assure the appropriate level
of maintenance, the proposal in paragraph (e) would require this
maintenance to be done by a trained person. This does not preclude the
operator from sending instruments to the manufacturer or another repair
facility for regular servicing.
Additionally, the proposal would require the operator to assure
that any instrument sent underground is in permissible condition so
that the use of the instrument does not pose an explosion hazard. The
level of care that must be exercised is of course a function of
instrument usage but, at a minimum, the Agency would expect that the
detector be visually examined to assure that it is properly assembled
and that all necessary components such as screws, lenses, and indicator
lamps are present. As with the requirement that maintenance be done by
a trained person, this requirement was present in the previous standard
and is being proposed to further assure that methane detectors do not
pose a hazard and will perform properly during the shift.
Section 75.321 Air Quality
This proposal would continue a basic air quality requirement that
has been in place since 1970 that air in areas where persons work or
travel contain at least 19.5 percent oxygen and not more than 0.5
percent carbon dioxide, and the volume and velocity of the air current
in these areas be sufficient to dilute, render harmless, and carry away
flammable, explosive, noxious, and harmful gases, dusts, smoke, and
fumes. The proposal would not require this carbon dioxide level to be
applied to bleeder entries and worked-out areas.
MSHA has interpreted former Sec. 75.301 to require at least 19.5
percent oxygen and no greater than 0.5 percent carbon dioxide in
bleeder systems where persons work or travel. Similarly, it was the
intent of the Agency to enforce Sec. 75.321 to require compliance with
these levels where persons would be exposed in bleeder entries and in
worked-out areas. However, the application of this provision to
bleeders has been stayed by the D.C. Circuit pending the outcome of
litigation on the rule. The Agency continues to believe that providing
satisfactory air quality is essential to protect the miners and
examiners whenever they work or travel in bleeder entries and worked-
out areas. Therefore, the proposal includes a new provision specifying
that the air in bleeder entries and worked-out areas where persons work
or travel contain at least 19.5 percent oxygen, and that carbon dioxide
not exceed 0.5 percent TWA (Time Weighted Average) and 3.0 percent STEL
(Short Term Exposure Limit). A TWA is the time-weighted average
concentration for a normal 8-hour workday and a 40-hour workweek. A
STEL is a 15-minute TWA exposure which can not be exceeded at any time
during a workday even if the 8-hour TWA is within the specified TWA.
Exposures above the TWA up to the STEL can not be longer than 15
minutes and can not occur more than four times per day. There must be
at least 60 minutes between successive exposures in this range. These
proposed levels are identical to the levels contained in MSHA's
proposed air quality standards for coal and metal and nonmetal mines
and the 1992 Threshold Limit Values (TLV) as specified by the American
Conference of Governmental Industrial Hygienists.
In light of the ongoing air quality rulemaking, the Agency is not
at this time proposing to modify existing air quality standards as
applied to areas where persons work or travel, other than bleeder
entries and worked-out areas. The Agency will consider the appropriate
course of action on this issue as part of the air quality rulemaking.
Bleeder entries and worked-out areas are required to be traveled or
evaluated at least weekly. This is most often done by a person
traveling alone who is often required to be in the bleeder entries or
worked-out areas for an extended period. The purpose of this standard
is to protect miners, not to regulate air quality where persons are not
exposed. Therefore, oxygen and carbon dioxide levels at bleeder
connectors and bleeder evaluation points that do not meet the proposed
concentrations would not constitute a violation of the standard if
examinations are performed remotely or if persons making the
examination can otherwise remain in air that meets the proposal.
According to the National Institute for Occupational Safety and
Health (NIOSH) of the U.S. Department of Health and Human Services
(NIOSH Respirator Decision Logic, May 1987), 19.5 percent oxygen
provides an adequate amount of oxygen for most work assignments and
incorporates a safety factor. Also according to NIOSH, the safety
factor is needed because oxygen-deficient atmospheres offer little
warning of danger. In the NIOSH publication, ``A Guide to Safety in
Confined Spaces,'' (page 4), a chart is presented that indicates that
19.5 percent oxygen is the minimum level for safe entry into an area,
and that at a level of 16 percent, judgement and breathing are
impaired. The American National Standards Institute (ANSI), in ANSI
Z88.2-1992, ``American National Standard for Respiratory Protection''
recognizes that at 16 percent oxygen there is an impairment in the
ability to think and pay attention, and a reduction in coordination.
ANSI recognizes that at 19 percent oxygen there are some adverse
physiological effects, but they are unnoticeable.
The need for regulating the oxygen level where persons work or
travel in bleeder entries is illustrated by two mining accidents. One
of these accidents resulted in the death of a mine examiner and the
second resulted in the near death of two additional individuals, one of
whom was a mine examiner. Mine examiners are, through training and
experience, the individuals best able to identify the hazards
associated with irrespirable atmospheres. The first accident occurred
at the Arclar Mine in Equality, Illinois in 1989. Prior to
implementation of the existing standard, a mine examiner, for unknown
reasons, entered a worked-out area that was posted with a danger sign.
Under the existing regulation, ventilation or sealing of this area,
rather than posting, would be required. Because the area was not
sealed, the existing regulation would require the area to be examined
during the weekly examination. The proposal would require that the
route of travel for the examiner would contain at least 19.5 percent
oxygen. Had the proposal been in place when the examiner entered the
worked-out area, there is a strong likelihood that he would not have
died.
The second accident, although not in a bleeder entry or worked-out
area, is illustrative of what can happen when individuals, including
mine examiners, are subjected to oxygen deficient air. In 1983 at the
Bird No. 3 Mine in Riverside, Pennsylvania, an assistant mine foreman,
a certified person, entered the mine for the purpose of conducting an
examination. After traveling approximately 1100 feet, the examiner
became dizzy, noticed that his flame safety lamp had extinguished and
withdrew approximately 200 feet where he sat down and apparently became
unconscious. A second individual upon entering the area in search of
the examiner also became dizzy but was able to withdraw to a location
that was not oxygen deficient. When the mine examiner regained
consciousness, his cap lamp battery had discharged and he traveled in
total darkness until he encountered a mine rescue team. Air samples
collected in the area where the mine examiner first became dizzy
indicated an oxygen concentration of about 16.8 percent, while other
samples collected nearby indicated oxygen concentrations of nearly 20
percent.
Because mine examiners are required to work or travel in areas
where oxygen-deficient air could occur without warning, and they
normally travel and work alone, there must be a requirement that
provides them the protection necessary for the performance of their
duties under these conditions. It is important that the level for
oxygen be established above that identified as resulting in impaired
judgement because it is essential that individuals traveling in these
areas remain highly alert. The hazards that can exist in bleeder
entries and worked-out areas include elevated methane levels, poor
footing, loose and unstable roof, and water accumulations. For this
reason, the Agency is proposing to adopt a minimum level of oxygen of
19.5 percent as recommended by NIOSH.
MSHA is also concerned with the effects of other gases often found
in bleeder entries. Section 75.322 of the existing regulation limits
the concentration of noxious or poisonous gases to the current (1971)
Threshold Limit Values (TLV's) as adopted and applied by the American
Conference of Governmental Industrial Hygienists (ACGIH). Section
75.322 specifically excludes carbon dioxide since it is covered by
Sec. 75.321. However, in light of the Court's stay of Sec. 75.321(a)
relative to bleeder entries, the Agency is proposing a separate
standard for carbon dioxide levels for areas where persons work or
travel in bleeder entries and worked-out areas. The levels proposed,
0.5 percent TWA and 3.0 percent STEL, when considered in conjunction
with the requirements of Sec. 75.322 and the proposed requirement for
oxygen, will aid in providing persons working or traveling in these
areas with a safe and healthful working environment. The Agency
recognizes that the effects of carbon dioxide are both chronic and
acute and has therefore elected to propose both a time weighted average
and a short term exposure limit. NIOSH, in recommending a standard for
carbon dioxide, also recognized this and recommended a similar
approach. The NIOSH recommendation, made in a Criteria Document
published in 1976, proposed a TWA concentration of 1.0 percent and a
ceiling value of 3.0 percent not to exceed 10 minutes. In making this
recommendation, NIOSH states that there are ``additive stress effects
of increased carbon dioxide concentrations and exercise * * *'' As
support for this, the NIOSH document cites research that showed that
healthy, trained subjects exposed to 2.8 to 5.2 percent carbon dioxide
at maximum exercise levels experienced respiratory difficulty, impaired
vision, severe headache, and mental confusion; three subjects
collapsed. At or below 2.8 percent carbon dioxide combined with lower,
but still strenuous, levels of exercise, no ill effects other than
awareness of increased ventilation were experienced by the subjects.
During rulemaking on the proposed air quality standard, NIOSH
recommended a 0.5 percent TWA and a 3.0 percent STEL. NIOSH made a
similar recommendation to OSHA during that Agency's permissible
exposure limit (PEL) rulemaking. Given the work environment in bleeder
entries and worked-out areas, as described earlier, the Agency believes
that the dual regulatory approach proposed is appropriate. In addition
to examiners, other miners may be required to work in the bleeder
entries and worked-out areas, performing duties such as installing roof
support, pumping water, recovering materials or adjusting ventilation.
The levels proposed would provide them with the necessary protection.
In addition, MSHA is concerned with the synergistic effects that
carbon dioxide has on the body when combined with low oxygen levels,
especially at levels higher than 0.5 percent TWA. Carbon dioxide
affects the blood pH, which is critical to the proper metabolism of
oxygen. Because of the nature of the hazardous work environment in
bleeder entries and worked-out areas, the Agency believes that it must
be careful to establish levels which would not impact on the body's
ability to deal with the conditions encountered. The Agency solicits
comments on the appropriateness of these, or other concentration levels
for carbon dioxide in areas where the examiner works or travels in
bleeder entries and worked-out areas, along with the rationale for
determining the appropriate level for bleeder entries and worked-out
areas. However, as stated previously, it is not the intent of the
Agency that the levels established in paragraph (2) of the proposed
standard be applied to areas other than those areas within the bleeder
entries and worked-out areas where persons work or travel. In light of
this, it is not anticipated that many of the nation's coal mines would
be required to increase the volume of air currently being used to
ventilate bleeders and worked-out areas as a result of this proposed
standard.
Section 75.323 Actions for Excessive Methane
MSHA is proposing to revise paragraphs (b)(1)(ii), (c)(1), and
(d)(2)(i) of the existing standard in response to comments made during
informational meetings and subsequent discussions.
Methane poses a significant hazard to miners when it is permitted
to accumulate without corrective action being taken quickly. The Agency
received comments at its informational meetings asking MSHA to clarify
when ventilation changes must be made to reduce methane concentrations
to acceptable levels. MSHA has always intended that these changes be
made at once. In response to these comments, the Agency is proposing to
revise paragraphs (b)(1)(ii), (c)(1) and (d)(2)(i) to require that
these changes be made ``at once,'' the phrase used in former
Secs. 75.308 and 75.309.
Although the Agency believes that the promulgation of paragraph (b)
of this standard was done appropriately, it is being reproposed with
the addition of the phrase ``at once'' for the purposes of receiving
and giving consideration to all pertinent comments. When 1.0 percent or
more methane is present in a working place, an intake air course, or an
area where mechanized mining equipment is being installed or removed,
paragraph (b)(1) would require all electrical, diesel, and battery-
powered equipment in the affected working place, intake air course or
other area, except for intrinsically safe AMS, to be deenergized or
shut off. Deenergizing or shutting off this equipment would protect
miners by preventing this equipment from providing ignition sources.
If 1.5 percent methane or more is present in a working place, an
intake air course, or an area where mechanized mining equipment is
being installed or removed, paragraph (b)(2) would require persons to
be withdrawn from the affected area. The basic requirement for
withdrawal of persons is retained from the previous standard and the
reproposal would expand this basic requirement to include areas where
mechanized mining equipment is being installed or removed. The presence
of methane in these areas can pose a significant risk to miners and
therefore their withdrawal from the affected area is essential to their
safety. Paragraph (b)(2) would also require that all electric power to
equipment in affected areas be disconnected at the power source. This
prevents accidental reenergization of equipment and removes power from
cables and circuits which may also be ignition sources. No other work
is permitted in the affected area until the concentration of methane is
less than 1.0 percent.
Paragraph (b)(2) would be amended by adding ``mechanized'' before
mining equipment for consistency with other provisions of the rule.
Section 75.324 Intentional Changes in the Ventilation System
MSHA is not proposing any changes to the wording of Sec. 75.324 at
this time. The following discussion clarifies MSHA's interpretation of
what the Agency considers to be an intentional change that could
materially affect the safety or health of persons in the mine.
Paragraph (a) of the existing rule requires that a ventilation
change be supervised by a person designated by the mine operator when a
change in section ventilation is in excess of a specified quantity or
when a ventilation change alters the main air current of the mine or
any split of the main air current in a manner that could materially
affect the safety or health of miners underground. Paragraph (b) of the
existing rule specifies additional requirements that apply only to the
ventilation changes described in paragraph (a) of this section. That
is, before such an intentional air change is made, electric power must
be removed from areas that may be affected by the change and mechanized
equipment in those areas must be shut off. Also, only persons making
the ventilation change are permitted in the mine while the change is
being made. Afterward, certified persons must examine the areas
affected by the change to determine whether methane accumulations or
oxygen deficiencies have resulted. Electric power is not permitted to
be restored to affected areas nor is mechanized equipment to be
restarted until these tests have been made and the areas are determined
to be safe.
Since this standard went into effect in November 1992, the Agency
has become aware of concerns suggesting that it is sometimes difficult
to determine whether an intentional change in the air current could
materially affect the safety or health of miners. However, MSHA regards
it as impractical to follow a ``cookbook'' approach to identifying what
will or will not require approval. Each circumstance is to be reviewed
by the operator on its own merits. To illustrate the Agency's
expectations, the following is a list of some examples of what MSHA
considers intentional changes that would materially affect the safety
or health of miners. These examples are not meant to include all
possibilities, but are meant to provide some general guidance: adding a
new shaft; bringing a new fan on line; changing the direction of air in
an air course; changing the direction of air in a bleeder system;
shutting down one fan in a multiple fan system; starting a new
operating section with ventilating quantities redistributed from other
sections of the mine; changing entries from intakes to returns and vice
versa; and any change that affects the information required by
Sec. 75.371, Mine ventilation plan; contents.
The results of changes to a complex ventilation system are not
always easy to predict, and for that reason caution must be used when
making significant changes to one air split or several air splits. The
balance of splits can be affected and may result in air reversals, dead
air spaces, or insufficient air flow in critical areas. For this
reason, such changes must be evaluated by a certified person examining
the affected areas before production is resumed. Approval is required
by paragraph (c) of Sec. 75.370 Mine ventilation plan; submission and
approval, if the change alters the main air current in a manner that
could materially affect the safety or health of miners. When questions
arise as to whether an anticipated change requires prior approval, MSHA
is available to discuss the situation for guidance on whether a request
for approval should be submitted. While the Agency is not contemplating
a change to Sec. 75.324 at this time, comments are specifically
solicited on the issues discussed.
Section 75.325 Air Quantity
Although the Agency believes that the promulgation of paragraph (d)
of this standard was done appropriately, it is being reproposed for the
purposes of receiving and giving consideration to all pertinent
comments. Paragraph (d) would require that areas where mechanized
mining equipment is being installed or removed be ventilated and that
the quantity of air and the ventilation controls necessary to provide
these quantities be specified in the approved ventilation plan. As
demonstrated by the explosion at the William Station Mine, ventilation
of these areas is essential and will greatly enhance the protection
provided to miners.
Section 75.330 Face Ventilation Control Devices
During the informational meetings and later discussions, it became
apparent that members of the mining community were concerned about the
appropriateness of using a performance standard relative to the volume
of air that must be provided to working faces. It was suggested that
such an approach suffered from two flaws: (1) By simply requiring
sufficient air, a problem could develop and go unnoticed before
corrective action is required; and (2) since most miners do not have
the means for measuring ventilation parameters; i.e., anemometers and
methane detectors, it may not be possible for the average miner to
determine compliance with the performance standard. It has been
suggested that in addition to the performance standard, the Agency
should propose requirements for line brattice similar to those that
existed in the previous regulation. After considering this
recommendation in light of the expressed concerns, the Agency is
proposing, in paragraph (c), that when a line brattice or other face
ventilation control device is damaged to the extent that ventilation of
the working face is inadequate, production activities would cease until
necessary repairs are made. It is the intent of the Agency to assure
that damaged ventilation controls are repaired and that mining is
discontinued until adequate face ventilation is restored.
Section 75.332 Working Sections and Working Places
Although the Agency believes that the promulgation of paragraph
(a)(1) of this standard was done appropriately, it is being reproposed
for the purposes of receiving and giving consideration to all pertinent
comments. The ventilation of working areas has historically been
accomplished through the use of a separate split of intake air. The
proposal would provide this same level of protection to miners working
in areas where equipment is being installed or removed.
The Agency is not proposing any changes to Sec. 75.332 at this
time. However, questions have come to the attention of the Agency
concerning the existing standard. The following discussion is intended
to address these questions.
The existing requirements of Sec. 75.332 are largely derived from
earlier MSHA regulations (Sec. 75.311 and Sec. 75.312). Under existing
Sec. 75.332, air which has passed through any area not examined under
Sec. 75.360, Sec. 75.361 or Sec. 75.364, or through any area which has
been second mined, cannot be used to ventilate any working place. After
the rule became effective, it was suggested that it would be possible
to ventilate working places with intake air coursed through an
evaluated, nonpillared worked-out area, because evaluation in lieu of
travel to the point of deepest penetration is at some times acceptable
under Sec. 75.364. As explained in the following discussion, this is
not the case. Existing Sec. 75.332(a)(1) requires that each working
section and each area where mechanized mining equipment is being
installed or removed be ventilated by a separate split of ``intake
air.'' Existing Sec. 75.301 defines return air as ``Air that has
ventilated the last working place of any working section or any worked-
out area, whether pillared or nonpillared * * *.'' Reading these two
existing provisions together, one concludes that air that has
ventilated a worked-out area is return air and therefore cannot be used
to ventilate any working section or any area where equipment is being
installed or removed.
A second question concerns the conditions under which air that has
passed by an unsealed worked-out area can be used to ventilate a
working section. Worked-out areas that are not sealed must be
ventilated, Sec. 75.334(a). Under Sec. 75.332(b)(1) the air used to
ventilate worked-out areas cannot be used to ventilate working
sections, unless examined in accordance with Sec. 75.360, Sec. 75.361,
or Sec. 75.364. There is only one condition under which air that passes
by a worked-out area that is not examined can be used to ventilate a
working section or an area where equipment is being installed or
removed. This is when the worked-out area is ventilated by a separate
split of air and the remainder of the intake air continues past the
worked-out area. This remaining intake air could be used to ventilate a
working section or an area where equipment is being installed or
removed. However, the air that enters the worked-out area cannot
reenter the intake air course because the definition of return air, in
Sec. 75.301, states in part that ``If air mixes with air that has
ventilated the last working place on any split of any working section
or any worked-out area, whether pillared or nonpillared, it is
considered return air.'' In the case of worked-out areas with multiple
openings, this would preclude air from being used to ventilate a
working place when it enters a worked-out area in one entry and exits
the worked-out area in another entry to remix with the air passing by.
To determine that the air that has passed by a worked-out area has
not been contaminated, proposed Sec. 75.360(b)(4) would require that
when intake entries carry air by worked-out areas to ventilate working
places where persons are scheduled to work, the approaches to the
worked-out areas be preshift examined immediately inby and outby each
entry that carries air into the worked-out area. The purpose of this
examination is to assure that the air is not oxygen deficient and does
not contain methane in excess of allowable limits and to determine that
the air is not coming from the worked-out area. By preshift examining
the intake entries in these areas, it can be determined that the air in
these entries is suitable for use in working places. Additionally,
proposed Sec. 75.360(b)(4) would require that when intake entries carry
air by worked-out areas to ventilate working places where persons are
scheduled to work, the entries used to carry air into the worked-out
area be preshift examined at a point immediately inby the intersection
of each entry with the intake air course. Preshift examining of these
entries is intended to assure that air that enters a worked-out area in
one entry does not reenter the intake air course.
While the Agency is not contemplating a change to Sec. 75.332 at
this time, comments are specifically solicited on the issues discussed.
Section 75.333 Ventilation Controls
The Agency is proposing to revise paragraphs (a), (b)(1), (b)(3),
(b)(4), and (e)(1) and add new paragraph (h) to Sec. 75.333.
As proposed, paragraphs (b)(1), (b)(3), and (b)(4) would be revised
to clarify the application of the permanent ventilation control
standards when a continuous face haulage system is used. Continuous
face haulage systems employ mobile bridge conveyors to transport coal
directly from the continuous mining machine to a low profile conveyor
belt. The mobile bridge system uses a ``dolly'' to transfer the coal to
the low profile conveyor belt at the section loading point. Because the
dolly travels along the low profile conveyor belt, the location of the
section loading point changes during mining as the mobile bridge dolly
moves. For escapeway purposes, paragraph (b)(4) would designate the
loading point for a continuous haulage system as the inby most point of
travel of the dolly.
In the past, the Agency has not required the use of permanent
ventilation controls to separate continuous face haulage systems from
return, intake, or primary escapeway entries in rooms developed 600
feet or less from the centerline of the entry from which the rooms were
developed. As with the existing standard, proposed paragraph (b)(1)
would require permanent stoppings or other permanent ventilation
control devices between intake and return air courses, except temporary
controls may be used in rooms that are 600 feet or less from the
centerline of the entry from which the room was developed. The proposal
would clarify the existing standard by explicitly stating that when
continuous face haulage systems are used, temporary controls may be
used to separate the system from the return and intake in rooms
developed 600 feet or less from the centerline of the entry from which
the rooms were developed. Because the room in which the continuous
haulage system is installed is continuously attended by the system
operators, an immediate response to any safety-related problem with the
haulage system would be expected. Additionally, two or three rooms are
often concurrently developed using this system and the life of the
actively developing rooms is often less than three days. The result of
this short life is that mining in these rooms would often be completed
before construction of permanent controls is finished. The proposal
recognizes the short-lived nature of these rooms and permits the use of
properly constructed temporary controls to deliver ventilation to the
faces. Requiring the construction of permanent controls in these
instances would result in no additional safety benefit. The Agency has
also received comment that additional material handling hazards would
be associated with the transportation of permanent control construction
materials into an often limited number of rooms during development.
Additionally, access to the continuous haulage system is required
through crosscuts for maintenance and operation of the system.
For these reasons, proposed paragraph (b)(3) would also be revised
to require that when continuous face haulage systems are used,
permanent stoppings or other permanent ventilation control devices must
be built and maintained to separate the haulage entry in which the low
profile belt structure is located from intake entries only to the outby
travel point of the dolly. The proposal would also provide that for
continuous haulage systems, temporary ventilation controls may be used
in rooms that are 600 feet or less from the centerline of the entry
from which the rooms were developed. In all other cases permanent
stoppings or other permanent ventilation control devices would continue
to be required to separate belt conveyor haulageways from intake air
courses when air in the intake air course is used to provide air to
active working places.
Proposed paragraph (b)(4) would continue to require permanent
stoppings or other permanent ventilation control devices ``* * * to
separate the primary escapeway from belt and trolley haulage entries,
as required by Sec. 75.380(g).'' In addition, the proposal would
require that when continuous face haulage systems are used, the loading
point for purposes of Sec. 75.380(g) would be the inby most point of
travel of the dolly. The Agency intends that this separation be
maintained to the most inby point of travel of the dolly in order to
provide protection along the entire length of the conveyor belt entry.
A greater or lesser distance for the separation of the conveyor belt
structure from the primary escapeway may be specified and approved in
the ventilation plan provided it poses no hazard to miners. This
provision is consistent with the requirements of Sec. 75.380(g).
The portion of the structure necessary to accommodate the movement
of the dolly is considered as part of the face haulage system.
Consistent with current MSHA policy, waterlines would not be required
to parallel continuous face haulage systems using a low profile
conveyor belt if the length of the belt is less that 600 feet and
sufficient fire hose is available to extend to the working face. Fire
suppression devices and signal and alarm systems are not required to be
installed along such conveyor belts. However, the belts considered as
face equipment must have fire protection at the belt drive as required
by Sec. 75.1100-2(e) of the existing standard and, if hydraulically
operated, must have fire suppression devices as required by existing
Sec. 75.1107. Additionally, for safety reasons, check curtains should
not be installed across the area of travel of the dolly.
The Agency has become aware of questions on the part of a segment
of the industry relative to what are acceptable construction methods
and materials for the construction of permanent ventilation controls,
excluding seals, that will result in controls that satisfy the
definition of durable given in paragraph (a) of the existing standard.
The Agency is addressing these questions by proposing to eliminate the
definition of durable and to modify paragraph (e)(1) to require these
controls to be constructed in a manner and of materials that results in
a construction that has been tested and shown to have a minimum
strength of 39 pounds per square foot as tested under ASTM E72-80
Section 12--Transverse Load-Specimen Vertical, load only. The proposal
retains the intent and requirement of the existing standard because the
8-inch hollow-core concrete block stopping with mortared joints, to
which all other constructions were tied under the definition of durable
in the existing standard, has been tested and shown to have a minimum
strength of 39 pounds per square foot.
The Agency recognizes that other construction methods and materials
may be available or developed that will result in permanent ventilation
controls that are suitable for the intended purpose. The proposal would
permit alternative constructions for ventilation controls constructed
after [INSERT THE EFFECTIVE DATE OF THIS RULE] under paragraph
(e)(1)(i) provided they have been tested and shown to have a minimum
strength of 39 pounds per square foot. For a control to be acceptable,
the operator would have to demonstrate that the control has been tested
and shown to provide a strength of 39 pounds per square foot as tested
under ASTM E72-80 Section 12--Transverse Load-Specimen Vertical, load
only. In instances where a construction has already been tested and
shown to possess the requisite strength, the operator need only provide
documentation of the test results. MSHA will maintain and will make
available for review at each MSHA District Office a listing of
construction methods and materials that have been tested and have
demonstrated a strength of at least 39 pounds per square foot. Persons
wishing to have a construction method or material included in this
listing should submit documentation of testing to the Agency. To the
extent possible, MSHA will also maintain a listing of construction
methods and materials that have failed to demonstrate a strength of at
least 39 pounds per square foot when tested under ASTM E72-80 Section
12--Transverse Load-Specimen Vertical, load only. Persons wishing to
have a construction method or material included in this listing should
submit documentation of testing to the Agency. It should be noted that
solid concrete block stoppings that are dry-stacked and plastered on
only one side have not been shown to have a minimum strength of at
least 39 pounds per square foot when tested under ASTM E72-80 Section
12--Transverse Load-Specimen Vertical, load only. Unless a stronger
plaster is developed, it is unlikely that a stopping plastered on only
one side would be acceptable under the current rule or this proposed
revision.
As with the existing rule, the proposal would require, in paragraph
(e)(1)(ii), that all overcasts, undercasts, shaft partitions, permanent
stoppings, and regulators, installed after November 15, 1992, be
constructed of noncombustible material.
Also like the existing standard, the proposal lists materials that
would be suitable for these controls and would continue to prohibit
ventilation controls installed after November 15, 1992, from being
constructed of aluminum.
The Agency is proposing a new paragraph (h) to assure that all
permanent ventilation controls, including all doors and seals,
regardless of the construction date, be maintained to serve the purpose
for which they were built. Existing Sec. 75.333(e)(1) requires that
ventilation controls be maintained to serve the purpose for which they
were built. Because existing Sec. 75.333(e)(1) also specifies that
ventilation controls installed after November 15, 1992, be constructed
of durable and noncombustible material, a commenter questioned whether
the maintenance requirement applied only to ventilation controls
constructed after November 15, 1992. That is not the case. Given the
importance of these devices in preserving the integrity of the mine
ventilation system, MSHA is proposing the maintenance provision in a
new paragraph to explicitly state that all permanent ventilation
controls, including seals, must be maintained to serve their intended
purpose. With regard to seal maintenance, the Agency does not intend
that the maintenance standard would be applied to seals located within
another sealed area. Further, the Agency does not intend that the
standard would apply to seals which have become consumed within a gob
area which is ventilated and evaluated in a manner approved through the
mine ventilation plan.
Section 75.334 Worked-out Areas and Areas Where Pillars Are Being
Recovered
MSHA is proposing to revise paragraph (e) and to repropose existing
paragraph (f). A requirement would be added in paragraph (e) that
provides that in addition to designing mining systems so that worked-
out areas can be sealed, the location and sequence of construction of
proposed seals would also be specified in the approved ventilation
plan. Improper location and sequencing of seal construction can have a
deleterious effect on mine air quality and ventilation and therefore
the location and sequence of construction of these seals should be
reviewed and approved as a part of the ventilation plan. Under the
previous standard, the proposed location and sequence of construction
of all necessary mine seals was required to be submitted for approval
as part of the sealing plan required by Sec. 75.330. Under the existing
standard, the location of proposed seals is required to be shown on the
ventilation map required by Sec. 75.372. Showing the location on the
map does not subject the location to approval and therefore the Agency
agrees that it does not satisfy the objective of assuring proper
location and sequencing. The proposal would rectify this situation.
Through meetings with various segments of the mining community, the
Agency also became aware of a concern that paragraph (f) of Sec. 75.334
may have been promulgated without the benefit of adequate comment.
Paragraph (f) addresses mines with a demonstrated history of
spontaneous combustion or those located in coal seams determined to be
susceptible to spontaneous combustion. Although the Agency believes
that the promulgation of paragraph (f) of this standard was done
appropriately, it is being reproposed for the purposes of receiving and
giving consideration to all pertinent comments.
As discussed in the preamble to the existing standard, several
commenters suggested that bleeder systems should not be required for
all mines, stating that in some mines the practice of ventilating
worked-out areas increases the risk of spontaneous combustion by
supplying oxygen to combustion-prone materials in these areas. These
commenters requested that the final rule include provisions to address
spontaneous combustion. MSHA recognized the need to reduce the flow of
oxygen to areas where there is a likelihood of spontaneous combustion
and the existing rule requires the approved ventilation plan to address
spontaneous combustion in mines with a demonstrated history of this
hazard or mines that are located in coal seams determined to be
susceptible to spontaneous combustion.
Experience gained through application of this standard has
demonstrated that paragraph (f) applies to only a few mines. However,
studies by the Bureau of Mines have identified the volatile properties
of coal seams and have determined that certain seams are susceptible to
spontaneous combustion. The existing standard, as reproposed, is also
directed to mines in these seams.
Under paragraph (f) of the proposal, the approved ventilation plans
for mines that are susceptible to spontaneous combustion must specify
measures to detect methane, carbon monoxide, and oxygen concentrations
in worked-out areas. These measures must be taken during and after
pillar recovery and in worked-out areas where no pillars have been
recovered. The purpose of these measures is to determine if worked-out
areas must be ventilated or sealed. If the methane concentration or
other hazards in the worked-out area cannot be controlled while the
mine is limiting airflow to avoid spontaneous combustion, it may be
necessary to ventilate or seal the worked-out area. These measures also
help to determine the extent to which the worked-out areas can be
ventilated without increasing the spontaneous combustion hazard.
The Agency is concerned with the inability of some mines that have
a spontaneous combustion problem to reduce the oxygen content to a
sufficiently low level. It is well known that the oxygen level in a gob
varies depending on the location where the measurement is made. For
example, the periphery of a gob normally will have higher oxygen levels
than the interior of the gob. The oxygen level in the interior of the
gob is critical when dealing with spontaneous combustion. If conditions
are such that the oxygen content in critical areas within a gob cannot
be reduced below that necessary for a methane ignition to occur, a
bleederless system may not be appropriate. The Agency solicits comments
on this subject.
Under the provisions of paragraph (f) the operator is required to
specify the action that will be taken to protect miners from the
hazards of spontaneous combustion. This requirement would be triggered
if the mine has a demonstrated history of spontaneous combustion, or,
if an evaluation of the susceptibility of the coal seam to spontaneous
combustion leads to a mine operator determination that a bleeder system
should not be used. In these cases the approved ventilation plan must
specify the methods that the operator will use to control spontaneous
combustion, as well as accumulations of methane-air mixtures and other
gases, dusts, and fumes in the worked-out area.
During informational meetings and through the application of this
standard, the Agency has become aware that the conditions under which
air flow can be adjusted within a bleeder system is the subject of some
concern. The following discussion is intended to address this concern
and clarify the Agency's position. When adjustments to air flow in the
bleeder entries are needed to assure proper functioning of the system,
these adjustments would be made in accordance with Sec. 75.324,
Intentional changes in the ventilation system. As explained in the
preamble discussion of existing Sec. 75.324, when the adjustment in the
bleeder system results in a change in direction of the air in the
bleeder entry, this is a change in ventilation that could materially
affect the safety or health of miners, and the precautions of
Sec. 75.324 apply. As addressed under Sec. 75.324, other changes to air
flow in the bleeder entry may also materially affect the safety or
health of miners, and the precautions of Sec. 75.324 would apply.
However, it is not intended that each and every change to bleeder
ventilation be considered to materially affect the safety or health of
miners. For example, minor changes needed to correct a localized
condition, such as removing a methane accumulation in a high spot, may
be possible. The operator must evaluate each change prior to its
implementation and, if doubt exists as to whether the change is
material, safety dictates that the change be treated as a material
change and the provisions of Sec. 75.324 be followed.
Section 75.340 Underground Electrical Installations
MSHA proposes to revise paragraph (a) of existing Sec. 75.340 for
the purpose of clarifying the standard and to add requirements that a
visual and audible alarm be provided on installations utilizing
automatically activated doors and that, for installations equipped with
sensors, monitoring of intake air ventilating battery charging stations
be done with sensors not affected by hydrogen. For clarity,
requirements for underground electrical installations to be in either
noncombustible structures or areas or to have fire suppression systems
have been put into separate paragraphs. Paragraph (a)(1) sets out the
requirements that apply when a noncombustible structure or area is used
for underground electrical installations. Similarly, paragraph (a)(2)
sets out the requirements that apply when a fire suppression system is
used. A provision has been added to proposed paragraph (a)(1)(iii) that
requires that electrical installations be equipped with a device to
activate a visual and audible alarm located outside of the enclosure on
the intake side of the installation. In addition, to maintain
consistency with proposed paragraphs (a)(1)(ii) and (a)(2)(ii) of this
section, proposed paragraph (a)(1)(iii) would be revised to include the
provision that monitoring of intake air ventilating battery charging
stations be done with sensors not affected by hydrogen. Proposed
paragraph (a)(1)(iii) addresses installations which are ventilated with
intake air and equipped with sensors to monitor for heat and for carbon
monoxide or smoke for the purpose of activating and automatically
closing doors. The device would activate when the temperature reaches
165 degrees Fahrenheit or the carbon monoxide concentration reaches 10
parts per million above the ambient level for the area, or the optical
density of smoke reaches 0.05 per meter. The visual and audible alarm
required should be situated so that it can be seen or heard by persons
traveling in the intake entry immediately adjacent to the installation.
It was suggested to the Agency that these electrical installations may
be susceptible to fire and the fire could go undetected. The visual and
audible alarms would provide additional safety at these installations.
Section 75.342 Methane Monitors
Informational meetings, later discussions on the rule, and recent
experience have indicated that simply requiring methane monitors to be
maintained in permissible condition does not completely satisfy the
need for assuring proper maintenance. It was suggested that it is
necessary to have a requirement that a trained person perform
maintenance to preclude the possibility that a person with less than
the necessary understanding of the monitor and the permissibility
requirements would be assigned the task. Under the proposal, methane
monitors must be properly maintained at all times. Like the existing
rule, proposed paragraph (a)(4) would require that each methane monitor
be calibrated with a known air-methane mixture at least every 31 days.
The Agency would expect that, when necessary to maintain
permissibility, methane monitors would be calibrated more frequently.
To assure the appropriate level of maintenance, paragraph (a)(4)(i)
would require that this maintenance be done by a trained person. To
further assure the adequacy of the maintenance provided, paragraph
(a)(4)(ii) would require, similar to the previous standard, the
operator to develop and adopt a written maintenance program, a copy of
which would be made available for review by authorized representatives
of the Secretary and the representative of miners. The investigation
into the recent explosion at the No. 3 Mine, Southmountain Coal
Company, Inc., illustrates the importance of proper maintenance of
methane monitors and the need for assuring that maintenance and
calibration are being done properly. Although the Southmountain
investigation report did not conclude that the methane monitor on the
continuous mining machine was involved in the explosion, it did state
that, ``* * * the methane monitor was likely in a condition that would
not have allowed for accurate atmospheric monitoring of the area prior
to and at the time of the explosion * * *.'' Appendix H of the report
states, ``The methane monitor was not maintained as approved due to the
use of a rag in place of the sintered metal screen filter in the dust
guard. The methane monitor was not properly calibrated, as received. If
this condition existed at the time of the explosion, the methane
monitor would not have been able to accurately detect the presence of
methane.'' The Agency believes that the best way to assure that
maintenance and calibration are properly done is through a written
maintenance program with which everyone involved is familiar.
The Agency would expect that, at a minimum, the maintenance program
would include the following: (1) Checks to assure that all components
of the methane monitor are securely attached to the machine on which it
is mounted and that all packing glands are properly packed and secured;
(2) Checks to assure that the sensor head is installed as close to the
face end of the machine as practicable and that the vent holes and
filter(s) on the sensor head are not clogged with water, dust, or other
material; and (3) Checks to assure that the warning device can be seen
or heard by the machine operator at all locations from which the
machine is operated and that the lens(es) protecting the meter and
indicating lamps is not cracked or broken. The maintenance program
should also make provisions to assure that the methane monitor meter or
readout assembly is properly adjusted to indicate zero percent methane
when no methane is present and that it is not possible to defeat the
monitor by holding or blocking the machine's reset switch in the start
position. The program should also specify the procedure for assuring
that a warning is given when 1 percent methane is indicated on the
meter or readout assembly and that all motors and lights on the machine
are automatically deenergized when 2 percent methane is indicated on
the meter or readout assembly.
During informational meetings and subsequent discussions, MSHA
heard suggestions that without a requirement for a record to be
maintained of calibration tests, similar to that required by the
previous regulation, there would be no way for the Agency or miners to
verify that the tests were made. Upon reconsideration, and in light of
the Southmountain explosion investigation, MSHA agrees that records of
calibration tests would be beneficial and is therefore proposing, in
paragraph (a)(4)(iii), that a record of all calibration tests be kept
in a book maintained for this purpose on the surface at the mine. Like
other records required by this proposal, the records of methane monitor
calibration tests are to be made in a state-approved book or in a bound
book with sequential machine-numbered pages. This is being proposed to
reduce the likelihood that pages or records could be lost or misplaced.
Comments are solicited on the use of this type of recordkeeping book
and on an alternative approach wherein the Agency would develop, in
coordination with the states, books specific for the required records.
Under paragraph (a)(4)(iv) of the proposal, the records would be
required to be retained for at least 1 year at a surface location at
the mine and be made available for inspection by representative of
miners and by authorized representatives of the Secretary.
Section 75.344 Compressors
This standard specifies requirements for compressors in underground
coal mines. The proposal would revise paragraph (a)(1), redesignate
existing (b)(2) as (b)(3) and add new (b)(2) and (e).
Improperly used or maintained compressors can present a significant
risk of fire. To minimize this hazard to miners, the existing
regulation addresses the detection and suppression of compressor fires,
and specifies installation and operation requirements for compressors.
The Agency has stayed paragraph (a)(1) of Sec. 75.344 of the existing
regulation, which requires all compressors to be located in
noncombustible structures or areas. During the informational meetings,
it was brought to MSHA's attention that in some instances requiring
such a structure could present a fire hazard.
The proposal recognizes in paragraph (a)(1) that it is possible to
provide the desired level of protection by permitting compressors to be
operated while attended, rather than requiring that they be located in
noncombustible structures or areas. Commenters pointed out that
requiring all compressors, in

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A94-12054. Public record. Not legal advice.