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  Section 75.1910 -- Nonpermissible diesel-powered equipment; electrical system design and performance requirements

Q. Section 75.1910(b) provides that each electric conductor from the battery to the starting motor must be protected against short circuit by fuses or other circuit-interrupting devices placed as near as practicable to the battery terminals. Does this require that short circuit protection be provided on the negative ground off the battery if short circuit protection is provided on the positive lead? Does “each electrical conductor from the battery” also mean that the ground conductor has to have a short circuit protective device?
Short circuit protective devices are required to be provided for both positive and negative conductors in ungrounded direct-current electrical systems. In systems where one polarity is grounded, short circuit protection is required only in the ungrounded phase, as near as practicable to the battery terminal. Redundant protection may be provided, however, if desired.

Q. Section 75.1910(d) requires that the electrical system be equipped with a circuit-interrupting device by means of which all power conductors can be deenergized. Will a manually operated blade (knife) switch suffice?
Yes. Any circuit interrupting device such as a knife switch, rotary disconnect switch, manual reset circuit breaker, or contactor relay may suffice in this application provided: 1) it is placed in each ungrounded (power) conductor; 2) located as close as practicable to the battery terminals; 3) properly selected and installed in a circuit, in order that it may be operated within its electrical ratings without damage; 4) not automatically reset after being actuated; and 5) be designed or otherwise mounted in a manner which precludes its closing by force of gravity.

Q. Can one protective device be used under §75.1910(e) to protect a starter motor and a D.C. hydraulic pump motor when they are rated approximately the same, if the lower rating is used to size the short circuit protection device? They will not be used simultaneously at all times and do not perform the same duty.
Yes, that would be permitted. One overcurrent device may be used to protect one or more motors that do not operate simultaneously, provided it is capable of deenergizing the motor circuits if any one of the motors experiences an overcurrent condition, such as arcing and overheating.

Q. Does permissible diesel-powered equipment approved under part 36 meet the NEC provisions referred to in §75.1910(f)?
Section 75.1910 specifically applies to nonpermissible equipment, and therefore permissible vehicles currently approved under part 36 are not required to meet the provisions of paragraph (f). Electric conductors on part 36-approved equipment are required to have adequate current-carrying capacity for the loads involved, and are not necessarily constrained by the ampacity tables provided in the National Electric Code, 1968 (which are incorporated indirectly in paragraph (f) through reference to existing §75.513-1). Part 36 approvals that have been issued since March 16, 1982, have electrical system conductors with current-carrying capacities consistent with the Insulated Cable Engineers Association standards.

Equipment originally approved under part 36 that has its status converted from permissible to nonpermissible (necessitating compliance with §75.1910) must comply with paragraph (f). The equipment's conductor sizes would be considered in compliance with §75.513-1, in accordance with MSHA policy addressing the application of that section with respect to the ampacity ratings of power cables manufactured according to ICEA standards.

Electrical systems and components on diesel-powered vehicles approved under part 36 prior to March 16, 1982, were restricted to self-contained battery-powered headlight units approved under part 20. Because these units are self-contained without any external wiring connections, these systems would not fall within the scope of §75.1910.

Q. Section 75.1910(I) requires that cables enter metal frames of motors, splice boxes, and electric components only through proper fittings. Is wrapping insulated wires with rubber conduit where the wires pass through metal frames, holes, etc., sufficient for compliance with this requirement?
Yes. Paragraph (I) is intended to reduce the possibility of chafing of cable or wire insulation, which would expose or accidentally ground the conductors at points where they pass through compartment walls or metal frames of equipment. Existing MSHA policy allows insulated electric wires passing through walls of metal enclosures to be protected against damage with insulated bushings or suitable insulating material used in conjunction with a fitting or clamp that will prevent movement of the conductor in the opening. Wrapping insulated wires with rubber conduit in this application would also be considered sufficient to comply with the requirement of paragraph (I). The insulating material should be resistant to deterioration from engine heat and oil.

Q. Do the requirements of §75.1910(j), which address protection and insulation of batteries, apply to 12-volt batteries on light-duty equipment?
Yes. Twelve-volt batteries on light-duty equipment would be subject to the provisions in paragraph (j) if they are connected to the equipment's starting and charging system, because it has been documented that this application presents an increased risk of fire. Batteries associated with electrical systems and components independent of the equipment's starting and charging circuits are not included within the scope of the requirements of this section because they do not present the same risk of fire. Storage batteries on the special category of equipment under §75.1908(d) also do not fall within the scope of this requirement.

  Section 75.1911 -- Fire suppression systems for diesel-powered equipment and fuel transportation units

Q. Is a field modification necessary to change the location of the fire suppression system on a unit of permissible diesel-powered equipment?
The answer to this questions depends on the fire suppression details in the approval drawings that were submitted to MSHA as part of the application for equipment approval. You should either contact the with manufacturer or MSHA's Approval and Certification Center.

Q. If the fire suppression system has been installed by the equipment manufacturer, is a field modification for equipment approved under part 36 necessary? If the fire suppression system is installed by the fire suppression system distributor/ manufacturer, do we need a field modification?
If the fire suppression system has been installed by the equipment manufacturer in accordance with the approval, a field modification will not be necessary. However, if the fire suppression system has been installed by the system's distributor or manufacturer, a field modification may be necessary. You should contact MSHA's Approval and Certification Center for further information on the specific equipment and fire suppression system.

Q. Is a fire suppression system required on rail-mounted fuel cars (towed vehicle) with no electrical system?
Rail-mounted fuel cars that have no electrical components would not be required to be equipped with a fire suppression system. However, §75.1906(g) provides that non-self-propelled diesel fuel transportation units with electrical components for dispensing fuel that are connected to a source of electrical power must be protected by a fire suppression device that meets the requirements of §§75.1107-3 through 75.1107-6 and §§75.1107-8 through 75.1107-16. Additionally, if a diesel-powered vehicle is towing the fuel cars, it would be considered heavy-duty equipment and would be required under §75.1911(h) to have an automatic fire suppression system.

Q. Section 75.1911(a)(4) requires discharge nozzles on fire suppression systems to be protected against the entrance of foreign materials such as mud, coal dust, or rock dust. Can nozzles be “protected” by their location and/or orientation?
This is a performance-oriented requirement, and in some cases the location or orientation of nozzles will provide the necessary degree of protection, in some cases not. This may also depend on the specific conditions in the system's listing or approval.

Q. Does the final rule allow permissible equipment to be provided with either a manual or an automatic fire suppression system?
Yes. Under §75.1907(b)(2), diesel-powered equipment approved under part 36 must have an automatic or manual fire suppression system that meets the requirements of §75.1911.

Q. Section 75.1911(b) appears to require, for either a manual or an automatic fire suppression system, nozzle coverage for delivery of dry chemical to the engine, including the starter, transmission, hydraulic pumps and tanks, exposed brake units, air compressors, and battery areas on diesel-powered equipment, and electric panels or controls used on fuel transportation units and other areas as necessary. For a manual system, you do not need to have detectors, but for an automatic system you do, and the detectors must protect the areas listed above for nozzle coverage. Is this a correct interpretation of the regulation?
Yes. The coverage areas are the same for manual and automatic systems; fire detection is also required for the coverage areas of automatic systems. Specific coverage of the nozzles and detectors will also depend to a large degree on the requirements of the listing or approval for the fire suppression system.

Q. Are both manual and automatic fire suppression systems required to provide for automatic engine shutdown?
Yes. Section 75.1911(d) applies the requirement for automatic engine shutdown to both manual and automatic systems.

Q. Does installation of the automatic engine shutdown feature required under §75.1911(d) require a field modification on permissible equipment?
The answer to this question depends on the specifics of the machine approval. If the design is such that a field modification or extension of approval is required, mine operators should check wit the equipment manufacturers to determine whether they have applied for an extension of approval to put engine shutdowns into their safety systems. If this is the case, a field modification would not be necessary.

Q. If we choose to put an automatic rather than a manual fire suppression system on a piece of light-duty equipment (which is required to have only a manual system) does the system have to meet all the requirements of an automatic system, which are more extensive than for a manual system?
Section 75.1909(I) provides that self-propelled nonpermissible light-duty equipment must be equipped with an automatic or manual fire suppression system meeting the requirements of §75.1911. If an automatic system is provided on light-duty equipment, it must still meet all the requirements for automatic systems under §75.1911.

Q. Would a standard automotive disc brake rotor be considered an exposed brake part and therefore require fire suppression coverage?
As discussed in the answer to the question above, the areas covered by a specific fire suppression system will depend to a large degree on the requirements of the system's listing or approval. Standard automotive disc brake rotors are typically covered. Exposed spring-applied brakes must be covered in all cases, because they are typically the source of frictional fires.

Q. If diesel-powered equipment is operating in the intake escapeway, would the final rule require that it be equipped with a manual or an automatic fire suppression system?
Under the standards governing underground coal mine ventilation, either an automatic or manual system would be acceptable for most diesel-powered equipment. However, if the diesel-powered equipment is a dedicated personnel carrier, §75.380(f)(5) requires that the equipment be provided with an automatic fire suppression system if it is being operated in the primary escapeway.

Q. Section 75.1911(e) provides that the system be operable by at least two manual actuators, with one actuator located on each side of the equipment. On small light-duty equipment (e.g., an Isuzu pickup truck) is it acceptable to have only one actuator if it is located in the center of the operator's compartment and is accessible from either side of the vehicle?
This would not be acceptable. The standard requires two actuators.

Q. Section 75.1911(f) requires that the fire suppression system remain operative in the event of engine shutdown, equipment electrical system failure, or failure of any other equipment system. Does this requirement prevent the use of the vehicle battery as a power source for certain kinds of fire suppression systems, where the fire suppression system would not actuate automatically if the battery fails?
The requirement in paragraph (f) would prevent the use of such a system.

  Section 75.1912 -- Fire suppression systems for permanent underground fuel storage facilities

Q. Section 75.1912(a) requires that fire suppression systems for permanent underground diesel fuel storage facilities be listed or approved by a nationally recognized independent testing laboratory and appropriate for installation at a permanent underground diesel fuel storage facility. Has MSHA identified any such systems?
Certain manufacturers of fire suppression systems with Underwriters Laboratory (UL) or Factory Mutual Research Corporation (FM) listings or approvals have indicated that their dry chemical or foam/water fire suppression systems can be engineered to meet the requirements of §75.1912. Whether or not a system meets all of those requirements will depend on how the system is engineered and installed at the particular location.

These companies and systems types are:

AFEX, Division of Bonaventure Group, Inc.        Dry Chemical
5808 Lease Drive
Raleigh, NC 27613
(919) 7816610

Alison Control, Inc.        Foam/Water
35 Daniel Rd.
Fairfield, NJ 07006
(201) 5757100

Amerex Corp.        Dry Chemical
P.O. Box 81
Trussville, AL 351730081
(205) 6553271

Angus Fire Armor Corp.        Foam/Water
Kennebec Rd. & Broad St.
Angier, NC 27501
(919) 6396151

Ansul Fire Protection, Inc.        Dry Chemical or Foam/Water
One Station Street
Marinette, WI 54143
(715) 7357411

National Foam System, Inc.        Foam/Water
150 Gordon Cr. Box 270
Exton, PA 19341
(610) 5944035

Pem All Fire Extinguisher Corp.        Dry Chemical
Division of Pem Systems
39A Myrtle St.
Cranford, NJ 07016
(908) 2760211

Pyro Chem, Inc.         Dry Chemical
301 Division St
Boonton, NJ 07005
(800) 5261079

The 3M Company/Viking Fire Protection         Foam/Water
3M Center
St. Paul, MN 55144
(612) 7330444

Share Corp.         Foam/Water
P.O. Box 23053
Milwaukee, WI 53223
(414) 3554000

  Section 75.1913 -- Starting aids

Q. Does the final rule prohibit starting aids from being brought inby the last open crosscut?
Yes. Section 75.1913(c)(1) provides that volatile fuel starting aids shall not be taken into or used in areas where permissible equipment is required.

Q. Can starting aids be used in outby areas of the mine?
Starting aids can be used in outby areas in accordance with any recommendations provided by the starting aid manufacturer, the engine manufacturer, or the machine manufacturer. Manufacturers of starting aids typically provide instructions for use of their product. Most engine manufacturers provide recommendations for starting aid use or specify that starting aids not be used at all with their engine. A prohibition on the use of starting aids by either the engine or the machine manufacturer would preclude their use with that particular engine or machine. Personnel who use starting aids must first be task trained.

Q. What is the rationale for prohibiting other volatiles in the same metal enclosure as starting aids?
This prohibition addresses the concern that containers of volatile fuel starting aids could be damaged through contact with other items, resulting in the release of the starting aid and the creation of a potentially hazardous situation.

  Section 75.1914 -- Maintenance of diesel-powered equipment

Q. What is meant by “approved” in §75.1914(a)?
The term “approved” used in the phrase “maintained in approved condition” means that the features of the engine, the power package, or the machine that were evaluated during the approval are maintained consistent with the approval specifications.

Q. If equipment is not immediately removed from service, can two citations be issued, one for a violation of §75.1914(a), and one for a violation of §75.1725(a)?
Only one citation would be issued, in most if not all cases for a violation of §75.1914(a).

Q. Does a permissible machine have to be maintained in permissible condition if it is never used in an area where permissible equipment is required? In the past, MSHA would allow mine operators to remove the machine approval plate and the operator would no longer be required to maintain the machine in permissible condition.
The final rule requires permissible diesel-powered equipment to be maintained in approved condition, including permissible equipment that is operated in outby areas. There are several reasons for this requirement. Many types of approved diesel equipment are extremely mobile, moving easily from areas of the mine where permissible equipment is required to areas where it is not, and there is nothing to distinguish a piece of diesel-powered equipment that has not been maintained in permissible condition from one that has. Additionally, temperature sensors and other safety system components on diesel-powered equipment can be permanently damaged by exposure to high temperature exhaust gas when the equipment is not maintained in approved condition and a safety system is bypassed.

However, if the approval plate is removed from a machine, the machine could be converted to nonpermissible equipment. In converting the machine, those fire- and explosion-proof features that will no longer be maintained in permissible condition must be removed. This should be done in consultation with the equipment manufacturer to ensure that other interconnected machine safety features are not adversely affected and that a maintenance manual tailored to the converted equipment is made available. Any permissible components that are not removed must be maintained in accordance with the manufacturer's maintenance manual. Note that as of November 25, 1999, an engine approved under subpart E of part 7 must be used in nonpermissible equipment.

Q. Diesel-powered equipment is required to be maintained in approved and safe condition or removed from service. Does this apply only to those items that are subject to approval and that affect safety?
All machine features that are either approved or that affect safety must be maintained.

Q. Is it mandatory that an engine that is rebuilt run on a dynamometer to seat the ring before the engine goes underground?
The rule contains no specific provisions that address that issue. The rule simply requires that diesel-powered equipment be maintained in approved condition.

Q. Does electrical work on diesel-powered equipment have to be done by a person qualified under §75.153?
Work on electrical circuits and components associated with or connected to the storage batteries and integral charging systems, covered by §75.1910, must be performed by a person who has been qualified under §75.1915. Work on electrical systems on the machine that are not covered by §75.1910 must be performed in accordance with the electrical standards in subpart F of part 75.

Q. What constitutes a “qualified person”?
For purposes of §75.1914, a qualified person is someone who has successfully completed a training and qualification program that meets the requirement of §75.1915.

Q. Does a person who performs repairs and maintenance only on nonpermissible light-duty equipment have to be qualified under §75.1915?
Yes. The rule requires a person to be qualified under §75.1915 if he or she performs maintenance and repairs of approved features and those features required by §§75.1909 and 75.1910. As of November 25, 1999, nonpermissible light-duty equipment will be required to have an engine approved under subpart E of part 7, and is also required to be provided with a number of features under §§75.1909 and 75.1910.

Q. Is the equipment operator who checks fluid levels and performs basic tasks such as changing the air filter, changing the oil, greasing, etc., required to complete some kind of training course?
The person who performs those tasks is not required to be qualified under §75.1915. However, the individual must be task trained.

Q. Section 75.1914(c) requires that the water scrubber system be drained and flushed at least once each shift that the equipment is operated. What is MSHA's policy if the manufacturer's recommended practices allow for draining and flushing the water scrubber system less often than at least once a shift?
The requirement of paragraph (c) must be complied with, regardless of whether a manufacturer recommends less frequent flushing than once a shift. Routine cleaning of scrubbers, which cool equipment exhaust gases and act as flame arresters, is essential to prevent a buildup of solid exhaust particles and sludge in the scrubber, which can hamper its effectiveness. Cleaning the scrubber more frequently than the manufacturer recommends should have no adverse effects on the equipment.

Q. When a diesel-powered scoop has been used to load rock, must the scrubber be cleaned and flushed after each shift?
Section 75.1914(c) requires that the scrubber be drained and flushed every shift on all diesel-powered equipment, regardless of the function the equipment performs.

Q. Section 75.1914(e) requires the equipment operator to visually examine mobile equipment before the equipment is placed in operation. Must the equipment operator complete the training program required under §75.1915?

Q. When testing is being conducted of temperature sensors, such as the engine temperature shutdown or the exhaust temperature shutdown, may the mine operator conduct the test at the mine maintenance shop, and then send the tested units underground to replace existing temperature shutdown units on machines in the mine?
Yes. The rule does not specify a location where these tests must be conducted, only that the tests be conducted at the required intervals.

Q. Will MSHA or the manufacturer approve the checklists for examinations of diesel-powered equipment, and what will the process be for getting such checklists approved?
MSHA is in the process of developing permissibility checklists to be used to conduct the weekly equipment examinations of part 36-approved diesel equipment required under §75.1914. MSHA has reviewed existing permissibility checklists that are part of the documentation for equipment that has already been approved by MSHA under part 36. MSHA has identified the specific items to be covered during the examination, and forwarded this information to manufacturers of the great majority of diesel equipment used underground, for the manufacturers' review. MSHA intends that the scope of the weekly examinations of diesel-powered equipment under §75.1914 will be similar in scope to the weekly examinations of electrical equipment performed under existing regulations.

MSHA anticipates that equipment manufacturers will be submitting modified checklists to the Agency for review and incorporation into their equipments' approval documentation. Although equipment manufacturers are responsible for making the revised checklists available to their customers, MSHA has begun to publish lists of the approval numbers of equipment whose checklists have been modified through this process. MSHA has also prepared a generic weekly checklist, which can be used for equipment without revised checklists or can supplement existing permissibility checklists until they have been revised.

Q. Section 75.1914(f)(1) requires diesel-powered equipment to be examined weekly. Are tests required on equipment that has not run in the last week?
MSHA takes a very broad view of what equipment is subject to weekly examination, and considers all equipment not located in maintenance shops or surface storage areas as being

subject to weekly examinations. Equipment that remains in the mine and that could be operated at any time, even if it has not been operated for an extended period, is subject to the weekly examination requirement.

Q. What is an example of a checklist that would be acceptable to the Agency?
MSHA intends to approach this issue so that the scope of the weekly examinations of diesel-powered equipment under §75.1914 is similar in scope to the weekly examinations of electrical equipment performed under existing regulations. MSHA has identified generically the items in existing permissibility checklists that should be included as part of the weekly examination of permissible diesel-powered equipment. These criteria are set forth below.

Power System Checklists

1. All visual inspection checks involving the intake system and exhaust system (e.g., gasket installation, bolts in place and tight, no loose connections, cracks and missing port plugs, etc.)
2. Engine stop button is operational.
3. No air system leaks.
4. Low Water Shutdown Test
5. High Exhaust Gas Temperature Sensor test for dry systems and scrubber systems with exhaust particulate filters.
6. Emergency Air Intake Shutoff Valve test
7. On-board diagnostic vacuum and pressure gage measurements.

Machine Checklist:

1. All checks involving the fuel system.
2. Service and Park Brake Test and/or Brake Adjustment Check.
3. Fire Extinguisher and Fire Suppression System Check.
4. Main air pressure gage is operational.
5. Approval plate is attached.
6. Neutral start feature test.
7. Exhaust diffuser installed.
8. Diesel particulate filter checks.
9. Warning gong operational check.
10. Platform free fall prevention test.

Electrical Permissibility Checklist

All visual and feeler gage inspection checks involving the electrical components, cables/conduit, lead entrances (packing gland).

The preamble to the final rule also states that MSHA would consider a mine operator to be in compliance with this provision if operators develop their own checklist formats based on and consistent with approved checklists and the manufacturer's maintenance manuals.

Q. Will any special testing procedures (in addition to permissibility checklists) be required on rebuilt engines prior to returning them to service underground?
Equipment including rebuilt engines and equipment must be maintained in approved condition.

Q. Are the weekly examinations by a qualified person to be conducted every 7 days, or is during the calendar week (as the current MSHA Program Policy Manual provides for electrical examinations)?
The approach for weekly examinations for diesel-powered equipment would be the same as weekly examinations for electrical equipment -- weekly examinations must be conducted once during the calendar week.

Q. Does the final rule require a record to be kept of the examination of diesel-powered equipment?
The final rule requires that persons performing weekly examinations and tests of diesel-powered equipment make a record when the equipment being examined or tested is not in approved or safe condition. The record must include the equipment that is not in approved or safe condition, the defect found, and the corrective action taken.

Q. How should a mine operator address a defect found on a piece of diesel-powered equipment during the weekly examination?
If it is a defect that renders the machine unsafe or not in approved condition, the defect must be corrected or the machine removed from service. The operator must also make a record of the defect, and indicate what corrective action has been taken.

Q. Is the calibration gas (CO) used to perform the weekly undiluted emissions tests under §75.1914(g) on diesel-powered equipment required to be 2500 parts of CO per million parts of air?
No. The CO concentration of the calibration gas used to perform the emissions tests under §75.1914(g) should be whatever concentration is recommended by the manufacturer of the sampling device. The 2500 parts per million concentration referred to in paragraph (g)(4) is a limit on the CO concentration of the exhaust gas established in the test procedures for Category B engines in subpart E of part 7 of the final rule.

Q. What is the maximum concentration of CO that the final rule allows to be measured during the undiluted exhaust emission test under §75.1914(g) before the equipment is required to be taken out of service or corrective action taken?
Corrective action should be taken when changes in the concentrations of CO measured in the machine's undiluted exhaust emissions indicate that the machine's engine is experiencing a problem and is in need of repair or maintenance. The standard operating procedures that mine operators are required to develop for the undiluted exhaust tests are required by §75.1914(g)(4) to specify the concentration or changes in concentration of CO that will indicate a change in engine performance. Concentrations of CO shall not exceed 2500 parts per million, which is the limit for CO established in the test procedures for Category B engines in subpart E of part 7 of the final rule.

Q. A diesel-powered locomotive is used for heavy-duty work only for limited and discrete periods several times a year, i.e., to move shields during longwall moves. During the rest of the year the equipment is used only for light-duty work, i.e., to move supplies. The locomotive will be provided with all of the equipment features required for heavy-duty equipment under §75.1909. Must the equipment undergo the undiluted exhaust emissions tests required by §75.1914(g) every week, regardless of whether the equipment is being used for heavy-duty work in that week?
The undiluted exhaust emissions tests required under §75.1914(g) would only be required in those weeks when the equipment is used to perform heavy-duty work. However, MSHA recommends that the emission test be conducted in the week immediately preceding any week that the equipment will be used to perform heavy-duty work, to eliminate any question as to whether the requirement has been satisfied.

Additionally, it should be noted that the intent of this requirement is to monitor engine performance to determine when engine maintenance is necessary. Conducting this test intermittently or only a few times a year may not provide adequate data for this evaluation, particularly since the records of these tests are not required to be maintained for longer than a year. Mine operators should take these factors into account in developing their testing and evaluation procedures.

Q. Would it be possible to perform the weekly undiluted exhaust emissions test under §75.1914(g) on permissible equipment while running the equipment engine at maximum rpm to unload coal at the feeder?
The final rule simply requires the emissions test be conducted while the engine is operating under load. If this approach satisfies that requirement, there is no reason why this method could not be used in performing this test.

Q. Do samples required under §75.1914(g) for the repeatable loaded engine test have to be instantaneous? We have an Industrial Scientific gas analyzer that averages a sample over 1 minute. Is this acceptable?
The undiluted exhaust emissions tests under §75.1914(g) are not required to be instantaneous. However, the test methodology should be integrated into the standard operating procedures, and the procedures should indicate how the mine operator intends to interpret the results of the reading.

Q. How will the undiluted exhaust gas tests required under §75.1914(g) be conducted without endangering persons who have to stand in front of a vehicle under power? How do you safely achieve a loaded engine condition? And how do you accurately repeat this condition?
A person does not have to stand in front of a vehicle to perform the exhaust tests under paragraph (g). The Center for Diesel Research has developed guidelines for performing these tests. These guidelines are intended to serve as the basis for the standard operating procedures developed by the mine operator, and it is the mine operator's responsibility to ensure that these tests are conducted in a safe manner. The Center for Diesel Research's report (An Emissions-Assisted Maintenance Procedure for Diesel-Powered Equipment, “Evaluation of Technology to Reduce Diesel Particulates”) is available via MSHA's Internet Home Page.

Q. Where are weekly carbon monoxide samples collected under §75.1914(g) to be taken?
The samples required under paragraph (g) must be of the undiluted, untreated exhaust emissions, which means that emission samples must be taken directly from the tailpipe, not at any distance away.

Q. Is the undiluted exhaust test required on light-duty equipment?
No. The requirement for the weekly repeated loaded engine condition test applies only to permissible and heavy-duty nonpermissible equipment. The requirement for this test is limited to permissible and heavy-duty nonpermissible equipment because almost all of those types of equipment has a torque converter type transmission that can be used to apply the loaded repeatable test. Most light-duty equipment has a clutch, and a test method has not been developed for that type of equipment.

Q. How do you open the exhaust system on permissible diesel-powered equipment to conduct the undiluted exhaust emissions tests required under §75.1914(g) without affecting the permissibility of the equipment?
All part 36-approved equipment is provided with an exhaust backpressure test port, usually a pipe plug in the exhaust manifold. This port can be used for testing the engine's exhaust emissions. It should be noted that this test should be conducted outby in fresh air, so that the exhaust system does not create an explosion hazard.

Some equipment has already been approved under part 36 that is equipped with an explosion-proof quick disconnect port. This feature provides a ready connection for sampling instruments, and may even permit continuous exhaust gas monitoring.

Q. What are the recordkeeping requirements for the undiluted exhaust emissions test under §75.1914(g)?
The final rule requires the mine operator to develop and implement written procedures for weekly testing and evaluation of undiluted exhaust emissions from diesel-powered equipment used where permissible electrical equipment is required, and from heavy-duty nonpermissible equipment as defined in §75.1908(a). Section 75.1914(g)(5) requires that the testing and evaluation procedures address the maintenance of records that are necessary to track engine performance. These records are required to be maintained in accordance with the requirements of paragraph (h), which, among other things, specifies a 1-year record retention period.

  Section 75.1915 -- Training and qualification of persons working on diesel-powered equipment

Q. May mine operators conduct this training in-house?

Q. The final rule requires the mine operator to develop a diesel training and qualification program. Does MSHA approve that program ?
No. The regulations do not require MSHA approval of the training and qualification program.

Q. Do the regulations specify minimum requirements for the training and qualification program?
Yes. The regulations provide that the training and qualification program: 1) be in writing; 2) be presented by a competent instructor; 3) include an examination that requires demonstration of the ability to perform all assigned tasks with respect to diesel-powered equipment maintenance, repairs, examinations, and tests; and 4) address specific areas, including proper maintenance of approved features of diesel-powered equipment.

Q. What is the amount of time required for the diesel training?
The regulations governing diesel training and qualification programs are performance-oriented, and do not specify the amount of time that must be devoted to diesel training. Instead, the regulation provides that the training and qualification program must be “sufficient to prepare or update a person's ability to perform all assigned tasks with respect to diesel-powered equipment maintenance, repairs, examinations, and tests.”

Q. What type of documentation is required under this section?
A mine operator is required to maintain: 1) a copy of the training and qualification program; and 2) a record of the names of all persons qualified under the program. Both the training program and the record of qualified persons are required to be kept at a surface location of the mine and made available for inspection by authorized representatives of the Secretary and by miners' representatives.

Q. Does the actual name of a person qualified under §75.1915 to work on diesel-powered equipment have to be listed?
Yes. Section 75.1915(c) requires the mine operator to maintain a record of the names of all persons qualified under the training and qualification program.

Q. Is the miners' representative entitled to a copy of the training and qualification program?
Yes. Section 75.1915(c)(2) requires that a copy of the training and qualification program be kept at a surface location of the mine, and be made available for inspection by an authorized representative of the Secretary and by miners' representatives.
Q. Does the instructor who provides the training have to be qualified under §75.1915?
There is no requirement that the person who provides training under §75.1915 also be qualified under §75.1915. A competent instructor could be a person qualified under §75.1915, an instructor from a trade school or college, or a person experienced in diesel maintenance, such as a representative of an equipment or engine manufacturer, or even the chief of maintenance at the mine, provided that the instructor has the necessary technical expertise.

Q. Would an instructor with a diesel maintenance background, and who has been approved by MSHA under the existing training program at our mine, be considered a “competent instructor” under §75.1915?
The determination of whether an instructor is “competent” for purposes of §75.1915 is the responsibility of the mine operator, who must ensure that the instructor has the necessary technical expertise to provide the training.

Q. Section 75.1915(b)(4) requires an examination where a person wishing to be qualified to must demonstrate the ability to perform all assigned tasks with respect to diesel-powered equipment maintenance, repairs, examinations and tests. If the individual seeking to be qualified fails the test, may he or she still perform maintenance and repairs on diesel-powered equipment?
If the person seeking to be qualified has failed the required examination, he or she would not be a qualified person under §75.1915, and under the regulations would be prohibited from performing maintenance and repairs of approved features of diesel-powered equipment, and of the features required under §§75.1909 and 75.1910, as well as the weekly examinations and testing under §75.1914(f).

Q. Who has final decision on who passes or fails the examination?
The mine operator, or other person designated by the mine operator in the training and qualification program.

Q. Can a person who is not qualified under §75.1915 work under the supervision of a person who is qualified under §75.1915, and assist in the maintenance and repair of diesel-powered equipment?
Yes. However, the qualified person will be fully responsible for ensuring that all such work has been properly performed.

Q. Is a person who is qualified under §75.1915 to perform maintenance and repairs on diesel-powered equipment only qualified to work on permissible equipment?
It depends on what equipment the qualified person has received training for. A qualified person is not required to be trained on a particular type of equipment unless he or she performs work on it. However, a person who is untrained on a particular type of equipment is not a qualified person with respect to that equipment, and may not perform maintenance, repairs, and tests required to be conducted by a qualified person.

Q. How much time will be allowed to have all persons trained and qualified under §75.1915 to perform maintenance and repairs of diesel-powered equipment?
All persons who perform maintenance and repairs of specified features of diesel-powered equipment, as well as those persons performing weekly examinations and tests, must be qualified under §75.1915 as of November 25, 1997.

Q. The rule requires retraining “as necessary”. How often is this?
Mine operators should tailor the frequency of retraining to the conditions and practices at each mine, to ensure that all persons who work on diesel-powered equipment maintain the requisite level of expertise. Factors that could affect the timing of retraining include the frequency with which the qualified person works on specific pieces of diesel equipment; newly developed techniques for performing the required inspections and tests; and any modifications that may have been made to the equipment since the last training. Frequent retraining may be necessary at some mines to ensure that qualified persons retain sufficient skill and knowledge to perform their jobs effectively. At other mines where conditions are less changeable, retraining at greater intervals may be appropriate.

Q. Are equipment manufacturers' representatives and similar specialists required to be trained under this program? What about mechanics in rebuild shops off of the mine property?
It depends upon what functions those individuals are performing. It is incumbent on the mine operator to ensure that maintenance and repairs of diesel-powered equipment are performed by persons with the necessary qualifications, and that the diesel-powered equipment in use at their mines is maintained and/or rebuilt in approved and safe condition.

Q. Do the maintenance requirements of §75.1914 and the training and qualification requirements of §75.1915 also cover the integral electrical components of diesel-powered equipment (e.g., lights, alternators/generators, starters, etc.)?
Yes. However, maintenance and repair of non-integral electrical components, such as a on a generator or a welder that is operated off of a diesel-powered engine, would be covered by the electrical equipment requirements in subpart F of part 75.

Q. Are currently trained diesel equipment maintenance personnel “grandfathered” under §75.1915?
No. All persons who perform maintenance and repairs of specified features of diesel-powered equipment, or who perform weekly examinations or tests on such equipment, must be qualified under §75.1915 as of November 25, 1997.

  Section 75.1916 -- Operation of diesel-powered equipment

Q. Does the prohibition against the operation of unattended diesel-powered equipment apply to outby equipment?
Yes, this prohibition applies to diesel-powered equipment used anywhere in an underground coal mine.

Q. When is idling part of normal operation? For example, would the prohibition against the unnecessary idling of diesel-powered equipment still allow a person who is fire bossing to get off of a diesel-powered vehicle to mark initials and dates, if the person remains within sight and sound of the idling equipment?
The intent of this provision is that equipment parked at any location, including the loading point, will be shut down if it is not used to do work. Any idling of diesel-powered equipment idling must be required in normal mining operations. For example, the idling of six locomotives waiting to unload supplies is not necessary for normal operation, and would be a violation of this requirement. Leaving equipment idling while the operator eats lunch would also be prohibited. On the other hand, the next ram car waiting to be loaded by a continuous miner would not be considered to be idling. Generally, when an equipment operator leaves a machine the machine should be shut off. However, in the fire boss example given, the facts suggest that the idling is necessary for and part of normal mining operations. The machine would therefore not be required to be shut off for the short periods that the operator is off of the machine.

Q. Operators of diesel-powered equipment are frequently within 500 feet of the equipment but not necessarily in the line of sight of the equipment, e.g., rock dusters, fire bosses, pumpers. The equipment operators may be working behind stoppings or curtains for short periods of time. Would that equipment be considered attended?
Section 75.1908(c)(1) provides that “any machine or device operated by a miner” is considered attended. This requires a miner to be at the controls of the machine and within close proximity of the diesel engine. Examples would be a scoop operator or a roof bolter operator. Section 75.1908(c)(2) provides that equipment is attended if it is in the direct line of sight of a job site located within 500 feet of the machine, and that job site is occupied by a miner. This is intended to allow the operation of certain portable equipment, such as welders and sealant machines. MSHA does not intend to prohibit, for example, a miner at a job site which is within 500 feet and in the line of sight of the welding machine from performing the welding operation when his view of the welder is obstructed for short periods of time. Conversely, this requirement is not intended to allow a miner to be at the end of a rock dust hose at a job site that is out of sight of the rock dusting machine. The purpose of this requirement is to ensure that a person will be in a position to check the operation of the diesel machine and intervene if for any reason the machine should start to present a hazard, such as in the event of a fault or fire.

Q. Does the final rule require diesel-powered pumps to be attended?
Yes. Section 75.1916(e) provides that diesel-powered equipment shall not be operated unattended. This prohibition applies to all diesel-powered equipment.

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