Approval and Certification Center (A&CC):

Q. Who from MSHA will process field modifications?

A. A&CC personnel will evaluate the application and the District 9 personnel will inspect the vehicle.

Q. Where can I get a complete listing of approved engine ventilation rates and particulate indices (including different horsepower ratings)?

A. Contact A&CC, Robert Setren at 304-547-2070.


Office of Management and Budget:

Q. MSHA estimates the cost of new regulation as part of the rulemaking process. Does a follow-up review ever take place to evaluate how accurate the estimates were?

A. We do not recalculate the cost of the rule. However, for the information collection requirements, we do provide update our estimates as part of the burden hours associated with the recordkeeping requirements. The comment period on this update is currently open- [Federal Register: September 24, 1999 (Volume 64, Number 185)].


Part 36:

Q. Manufacturers have kits available to bring part 36 machines into compliance with the new regulations. If we install these kits onto our machine before the approval is issued for these modifications, is there any way we can use these machines until the approval process is completed?

A. No. We must issue the approval before you can modify and place the machine in service.

Q. For approval changes after certification; if a machine was approved under part 36, who is responsible for filing for changes to this machine because of new regulations?

A. Reference Robert Setren's presentation, attached.

Q. Were all equipment manufacturers that have part 36 approvals notified that their equipment could not be used after 11/25/1999 without modifications to meet the new requirements?

A. Yes. We conducted a special diesel workshop for manufacturers in February of 1997. Since then we have worked closely with manufacturers of both permissible and nonpermissible equipment. Permissible equipment manufacturers have been encouraged to submit applications for approval that meet the new regulations. This process would take the burden off mine operators to get field modifications.

Q. Please describe the areas on a machine approved under part 36 that would not meet the surface temperature requirements?

A. Exposed brake units may reach temperatures over 302 °F (the general surface temperature limit under part 36). However, there are no surface temperature requirements for brake units on part 36 equipment. All surfaces of the power package, which includes the engine and exhaust scrubber, must be below 302°F to meet the conditions of the approval.

Q. Has J.H. Fletcher submitted an approval application to cover their diesel-powered roof bolters?

A. We are discussing the requirements with Fletcher and expect an application.


Petitions for Modification:

Q. We currently have two petitions submitted. One involves the front brakes on the graders and the other involves the use of a dry scrubber instead of an approved engine on an outby generator. What is the status of these petitions?

A. The petitions are being processed. We will expedite both petitions.

Q. Will a petition for modification for section 75.1909(b)(6) be acceptable for the time extension?

A. Yes. You must file the petition before 11/25/1999.

Q. If a petition is in place for grader brakes, can the Agency grant provisions for the use of these machines after 11/25/1999 if the petition has not been granted?

A. Yes. PIB No. P99-15 allowed interim compliance and covers grader brakes. Like purchase orders, submitting a petition by 11/25/1999 is a good faith effort to comply.

Q. Has MSHA taken the stance that all petitions related to the diesel rules will be denied?

A. No. We anticipate granting petitions on grader brakes and on gensets with nonapproved engines. We have denied other petitions because mine operators did not make convincing arguments that the proposed alternate means would provide equivalent safety.


Program Information Bulletin (PIB) No. P99-15:

Q. Does MSHA anticipate a delay in the enforcement of these regulations?

A. Reference PIB No. P99-15.

Q. The recent Program Policy Letter (PPL) regarding fire suppression requirements gave much more direction and specific information concerning this issue. Are additional PPL's in the works to address other areas of the rule?

A. The PIB No. P99-15 and the new Compliance Guide II are the latest documents. We are looking into the concerns raised at the 9/28/1999 meeting in Price, Utah, and will respond to those concerns. We would welcome suggestions.

Q. TCC's Lube Trucks- TM00587 & TM00700- Wagner has not and does not plan to submit kits for approval to comply with the new law. Should TCC obtain field modifications for these machines?

A. Yes. Reference PIB No. P99-15.

Q. TCC's TM00477- Permissible 25X- This machine needs split brakes (this modification is approved), a brake release (we have the kit but it is not approved), a fire suppression shutdown (we do not have the kit and the kit has not yet been approved). How should we proceed?

A. Reference PIB No. P99-15.

Q. TCC's Petitto Mule- TM00347- Petitto has submitted the material to MSHA for the fire suppression and the brake release kit. How should we proceed?

A. Reference PIB No. P99-15.

Q. We have four ST 3½ scoops (#1, 5, 488, and Shoshone's SH62354) that have air over hydraulic park brakes. The rule does not allow this system since it traps a column of fluid to apply the brakes. Therefore, we will have to upgrade the machine to a complete hydraulic system. The biggest question surrounding these four scoops is whether or not we can obtain these kits in time to meet the deadline. There are a lot of machines of this type that require these upgrades. Parts have been ordered by TCC to bring these machines up to the 31-90-3 approval. The question is what do we do with the machines if parts are not here by the deadline?

A. Reference PIB No. P99-15.

Q. We currently have three Wagner ST3½ (#2,3,&6) with complete hydraulic brake systems that are approved under approval number 31-90-3. Wagner has submitted the upgrade kits for brake release, declutch, and fire suppression to MSHA for approval. If these kits are not approved will we need to have a field modification done prior to 11/25/1999?

A. Reference PIB No. P99-15.

Q. TCC's Permissible Teletram TM00350- Wagner has submitted the kits and we are waiting on the approvals. How should we proceed?

A. Reference PIB No. P99-15.

Q. TCC will allocate three mantrips to haul diesel fuel, which would allow an extension for these mantrips until May of 2000 if it includes nonpermissible equipment.

A. Reference PIB No. P99-15.

Q. For engines not approved until 9/1999, the procedures and costs to obtain these approval tags are not finalized. We doubt that the 178 plus tags we need can be ordered, processed, delivered, and installed by the 11/1999 date. What do we do?

A. See the Compliance Guide's cover letter- we will issue you a letter that will document the engine has been approved. This letter can be used as interim compliance until you receive the approval plate. You must make a good faith effort to obtain and install the plate as soon as practical.

Q. If an operator is unable to meet the 11/25/1999 deadline because of purchase, delivery, or retrofit problems, we will be faced with a decision to shut down their pre-99 equipment. If the operator chooses to continue to operate this equipment, it could result in a violation and possible closure order. How would we abate this? Also, the engine manufacturer's commitment to obtain engine approvals was too late for operators to reasonably commit to purchase new units until after the 1999 models ceased production. We received no deliveries until the third quarter of 1999. How are operators to comply with the November date for nonpermissible equipment?

A. MSHA will reevaluate the reported 500+ vehicles in District 9 that need to be upgraded. We will notify the industry to let them know how we will deal with this situation.

Q. Wouldn't an across the board delay penalize those operators who have worked to achieve compliance and reward those who have taken a wait and see approach?

A. The approach we have taken in PIB No. P99-15 only allows extensions for those sections of the rule that mine operators may not meet because of delays in obtaining unique parts or delays manufacturers and mine operators may experience in obtaining approvals and field modifications on part 36 equipment. Mine operators must show a good faith effort in meeting the rule through a valid purchase order for the necessary parts or retrofit kits. This does not reward those who may have taken a wait and see approach.

Q. What if we are seeking an engine certification but it is not completed, can a low negligence citation be issued while the emissions tests and application are being completed?

A. If you submit the application by 11/25/1999, the Agency will consider issuing a letter documenting the required air quantity after the tests are complete but before the approval letter is issued.


§70.1900(c):

Q. Will the incorrect use and application of the term "TLV" in section 70.1900(c) for action levels be corrected?

A. We consider the use and application of an action level based on 50% of the TLV for CO and NO₂ to be correct.


Part 75:

Q. Can MSHA provide training to inspectors which will emphasize that there are multiple ways of achieving compliance with the rules? Otherwise, mine operators will face having this rule reinterpreted with every new inspection. We have already seen this occurring with the small group of MSHA employees involved in the process to date. Left uncorrected, imagine what this will be like when it is expanded to the entire inspection force.

A. We are training all CMS&H inspectors on the diesel regulations. The training does emphasize that the rule is performance oriented and there are many ways to achieve compliance. For many regulations, mine operators can help in ensuring uniform compliance by providing the inspector with manufacturer's literature. This could include items such as switch rating information, fuse rating information (if not on MSHA's homepage), and manufacturer's fire-resistant fuel line documentation. As noted during the Utah Coal Association meeting on 9/28/1999, we are planning a joint MSHA-Industry training session on the regulation during the week of 11/8/1999.

Q. Based on our recent experience with changing compliance interpretations, MSHA will need to provide more specifics in almost every area of the rule.

A. Reference the previous question. We have taken several actions to achieve consistency in evaluating the diesel regs. The Compliance Guides clarify issues that have arisen since the publication of the rule and preamble. Our homepage provides up to date compliance information. We are also providing training to all CMS&H Inspectors on the diesel regs. Individuals knowledgeable of the diesel regs are presently in each District. CMS&H headquarters personnel are coordinating interpretation of the diesel regs across the Districts. Also as much as possible, considering the many ways to meet the performance requirements in the rule, the differences in machine designs, and the differences in mining operations, we will be consistent in enforcement of the regulations.

We will continue to fully support the implementation of these regulations. We will provide the industry with specific answers, in writing if requested, on all aspects of the rule.

Q. The problems we have been experiencing seem to be a direct result of this rule being performance based. Without specific information, we are subject to each inspector's "What if's." Without specific direction, an operator's compliance effort regarding this rule will never be completed.

A. The prevailing industry comments received during the rulemaking process supported performance-based regulations. It may be appropriate to repeat this comment during any future rulemaking process. However, we will continue to include on our homepage those specific designs (fuses, switches, area fire suppression systems, etc.) that meet the rule.

Q. Does MSHA plan to assign specific, specially trained inspectors to inspect diesel equipment?

A. No. We plan to train all inspectors on the diesel regulation.


§75.325(h):

Q. Certain equipment can be excluded from the ventilation requirements. If there is no history of problems, such as illness, injury, violations or comments from local field inspectors, why is it such a struggle to get these exclusions approved in the ventilation plan?

A. Certain equipment can be excluded under §75.325(h). To support exclusion of the equipment you must show that the machine falls into one of the following categories:

(1) Self-propelled equipment meeting the requirements of Sec. 75.1908(b); 

(2) Equipment that discharges its exhaust into intake air that is coursed directly to a return air course;

(3) Equipment that discharges its exhaust directly into a return air course; and,

(4) Other equipment having duty cycles such that the emissions would not significantly affect the exposure of miners

This is a performance-oriented requirement. The mine operator must protect the fire extinguisher from damage. There are many ways that this can be accomplished. In choosing the means of protection, the mine operator must consider the consequences of rupturing a high pressure fire extinguisher cylinder. Even less severe damage can render the fire extinguisher inoperative when needed.

During the Utah Coal Association meeting on 9/28/1999, a specific concern was raised about locating the fire extinguisher in the bed of a pickup truck and not providing any additional protection. We agree that this may be a reasonable approach to provide adequate protection for the fire extinguisher. By locating it in the bed of the machine, the extinguisher is protected from damage by collision with the rib and other machines. Depending on the use of the truck and the extinguisher's exact location, however, it may still be exposed to damage from falling material or material shifting in the bed of the truck. The mine operator must consider these hazards. If during an inspection, the fire extinguisher is found to have been damaged, MSHA will consider this to be a failure of compliance with the requirement to protect the fire extinguisher from damage. 

> This rule is a performance-oriented and the you must make a reasonable effort to comply with the regulations. Trial and error is not an acceptable approach to achieve compliance. The inspector will determine if a reasonable effort is being made based on the circumstances in each situation.

Our training video detailing the requirements for heavy duty vehicles shows a fire extinguisher on the top of a machine with no protection. The video states that this is not adequate protection. Locating the extinguisher within the frame of the machine (as in the operator's compartment or in the bed of a pickup truck) or in a safe location on top of the machine is considered a reasonable effort to comply with the requirements. The video does specify a higher level of protection than may be required of a mine operator by stating that the protection for the extinguisher is inadequate. We do not consider that this is necessarily a contradiction. The video describes modifications made to the machine at a rebuild shop. Equipment manufacturers, rebuild shops, and MSHA personnel evaluating equipment at these locations may not be fully aware of how the machine will be used at a specific mine. When this is the case, equipment manufacturers and rebuild shops should provide safety features for the expected worst case operation of the vehicle. Consequently, the video states that additional protection is necessary.


§75.1909(a):

Q. Why doesn't MSHA accept other Agency approvals? If a pickup has been approved for use on the highway why does it need additional approvals?

A. MSHA approves the diesel engine using the test described in part 7, subpart E. These tests are similar to the tests previously performed by MSHA under part 36. The test uses a steady state test cycle derived from an international standard. The purpose of the test is threefold: 1) to determine pass/fail of the engine by determining the maximum concentrations in the raw exhaust of Carbon Monoxide and Oxides of Nitrogen. The concentrations of these two gases cannot exceed limits specified in the regulation; 2) determine the gaseous concentrations of Carbon Monoxide, Carbon Dioxide, Nitric Oxide, and Nitrogen Dioxide over the test cycle to calculate a gaseous ventilation rated (nameplate air quantity expressed in cubic feet per minute of ventilation air) based on the worst case condition; 3) determine a particulate index based on a weighted average of the diesel particulate collected over the test cycle. The particulate index is based on dilution of particulate to 1 mg/m^3.

Some regulatory bodies, such as the USEPA, as well as the State of California regulate emissions from diesel engines for both on-highway vehicles and off-road vehicles. The EPA and California certify on-highway diesel engines using a transient test cycle. In 1995, the EPA and California started regulating non-road engines using a steady state test cycle similar to the test cycle used by MSHA. The EPA and California set limits on amounts of emissions emitted intothe atmosphere per year from vehicles. MSHA determines concentrations of the emissions to determine dilution quantities to maintain certain concentrations in the mine atmosphere. We cannot relate the emission results from transient tests to the data needed for calculating the worst case emissions to get the ventilation rate. Transient tests gives time weighted averages, not specific gaseous concentrations at specific test points.

The test cycle used by EPA and California for non-road is similar to MSHA. However, EPA and California measure Oxides of Nitrogen whereas MSHA measures Nitric Oxide and Nitrogen Dioxide separately since both gases have distinct Threshold limit values (TLV's). For nonpermissible engines, the Nitrogen Dioxide is generally low. If the total Oxides of Nitrogen concentration was used, a higher ventilation air quantity would be calculated. EPA and California only use the data to look at the engine not exceeding a specified level. MSHA calculates the gaseous and particulate index.

It is likely that most engines used in vehicles considered light duty in the mine, such as pickup trucks, are tested by the EPA and California over the transient test cycle for on-highway use. Generally, engine manufacturers have not been certifying these engines separately for non-road use. Again transient data cannot be used to calculate the required dilution air quantities. Often, the engines that are EPA and/or California certified for non-road use are setup in different configurations due to vehicle usage or emissions output. California in some cases has more stringent emissions requirements than EPA and the engine manufacturer has to make additional adjustments to the engine. Therefore, those engine test results would not represent the engine in the underground vehicle.

> MSHA did request comments on the use of EPA certified engines in their proposed rule for Metal/Nonmetal diesel particulate control. MSHA did receive comments and is reviewing this information.


§75.1909:

Q. There are some issues that are not clear, i.e., if they are needed or not or where;

a. Skid plates

A. You must substantially construct and protect the fuel tank. Skid plates are one means to accomplish this. As with fire extinguishers, you must provide reasonable protection. Unlike fire extinguishers, the fire risk from a ruptured fuel tank is significant and mine operators and inspectors should consider this when determining what is reasonable protection. For on-highway pickup trucks, unless the mine operator can show good road conditions or that the truck is designed for off-road use (the truck provides additional ground clearance for the fuel tank) the OEM fuel tank protection will not be considered adequate.

b. Oil fill guards-

A. See the new Compliance Guide II.

c. Starter guarding-

A. See questions on fusing/circuit breakers. Also, see the new Compliance Guide. Note that the surface temperature of starters is not likely to exceed 400°F. Therefore, they do need to be treated as a hot surface when addressing possible ignition sources for the leak or spray of fuel or hydraulic fluid. The fire suppression system must still cover them to address the possible ignition source from an electrical fault in the starter.


§75.1909(a):



Q. What percentage of engines currently in use will become obsolete on 11/25/1999?

A. From our Diesel Inventory, fifteen percent must be removed from service. We expect 85% to be approved. This is a nationwide percentage. For District 9, we expect that 32% (350) of the engines will be obsolete on 11/25/1999. Of these 350 engines, about 100 are Isuzu model C233 engines. The mines most affected appear to be Deer Creek with 48 obsolete engines, Trail Mine with 43 obsolete engines, Star Point #2 with 37 obsolete engines, and Skyline No. 3 with 23 obsolete engines.

Q. The list of machines with approved engines is posted on the MSHA Web site. As of Friday, September 24, 1999, that list contains just three equipment types. How many more have been submitted for approval?

A. We will post a list of machines for which applications have been received on our homepage.

§75.1909(a)(3)(ix):

Q. Please explain some alternatives available for the separation of electric wiring, fuel and oil lines.


A. Reference Compliance Guide I:

"Q. To what extent must fuel lines and electrical wiring be separated to comply with §75.1909(a)(3)(ix)?

A. There are several different methods that can be used to comply with this requirement. These include physical separation by distance of the fuel lines from the electrical wiring. Other methods include placing the wires or fuel lines into a conduit, or bundling the electrical wires above the fuel lines, to ensure that no fuel will drip on the wires.

> The key hazard addressed by §75.1909(a)(3)(ix) is that leaks of combustible fuel not drip on electrical wires. The wires could arc or overheat and ignite the fuel. You must provide a means to eliminate this hazard.

§75.1909(a)(3)(vii):

Q. Do fuel lines (metal) that are an incorporated part of the engine have to be shielded or not?

A. Engine OEM installed fuel lines do not require guarding. These lines, however, are high pressure lines that can leak. You must maintain them so that they do not leak.


§75.1909(a)(3)(x):

Q. As for fuel shutoff valves, what is the rationale in defining "as close as practicable" to be 15 inches?

A. Reference Compliance Guide I:

Q. With regard to the manual shutoff valve requirement in §75.1909(a)(3)(x), can the shutoff valve be located in utility vehicles (Ford, Isuzu, etc.)?

A. Yes. The accessibility to the shutoff valve is as important a consideration in determining the location of the valve as is the proximity of the valve to the tank."

The fuel shutoff valve is not required to be within 15" of the tank. It can be located more than 15" from the tank to provide easy access for maintenance personnel and still meet the "close as practicable" requirement. The closer the shutoff valve is to the tank the greater the length of fuel line that will shutoff by the valve in the event of a leak.

§75.1909(a)(10):


Q. Please describe some of the alternatives available for protection from oil leaks spraying on hot surfaces?

A. Sections 75.1909(a)(6)&(10) cover this hazard. Two methods are typical. Covering the hot surfaces with a nonabsorbent insulating material would meet this requirement. The surface temperature of the insulating material must be less than the lowest autoignition temperature of fluids used on the machine (the lowest is typically 400°F for diesel fuel- 1909(a)(3)(viii) covers leaks of diesel fuel). The second method typically used is to install conduit over the lines to control the spray if the line ruptures. The conduit must cover fittings and have an opening that will direct fluid away from hot surfaces while preventing the conduit from being pressurized. Split conduit, typically used to protect wiring, may also be suitable for this application. The conduit must be designed for use in the engine compartment (heat and oil resistant). The split conduit must be large enough to completely cover the hose. The split portion of the conduit should overlap and be secured such that a spray of high pressure fluid will not escape from the conduit or blow the conduit off of the hose. Leakage from the conduit must be directed away from hot surfaces.

Q. At this time we were told that the fire sleeve must cover the metal fittings on both ends of a hose and be clamped at the highest part and not on the lower end. This is so that the fluid could run out the lower end and not rupture the sleeve under pressure.

A. Within the context of the discussion of the particular machine and the way the mine operator chose to meet the rule, this is correct.

Q. We were told that in areas where fire sleeves were needed that it was to run from metal fitting to metal fitting.

A. If conduit is installed to prevent the spray of broken hydraulic lines from being ignited by hot exhaust system surfaces then this includes coverage of the fittings. Loose or cracked fittings can allow the spray of hydraulic fluid.

§75.1909(a)(10):


Q. If metal fuel lines are acceptable and do not need additional fire protection, then why do metal fittings on hoses or lines have to be covered?

A. The fire hazard presented by fuel lines and hydraulic lines must be addressed. These hazards are addressed by the rule in several ways. Since diesel fuel is likely to have the lowest autoignition temperature of any fluid on the machine, the fuel lines must resist burning. Metal lines are one way to achieve this. Fuel lines must also be located so they can not leak onto hot surfaces. This can be achieved by locating the fuel lines away from hot surfaces or containing the leak through the use of conduit. Sprays from hydraulic lines and the metal fittings of hydraulic lines must be addressed. Covering these components is one way to prevent the spray from either a broken hose or a loose or cracked fitting from spraying on a hot exhaust surface.

§75.1909(b)(6):


Q. Why doesn't MSHA issue a policy statement on grader brakes (a requirement accepting alternative means of providing equivalent safety instead of front brakes) instead of requiring a petition?

A. The rule is specific in requiring brakes that act on each wheel. We can't change the rule by policy.

Q. Manufacturers have refused to install front brakes on graders because it would make them unsafe. Can you remove the requirements for steering axle brakes on road graders administratively, or will this continue to require a petition?

A. It is MSHA's position that well-designed front brakes that act on each wheel on graders provide an increased level of safety. Petitions to document the mine operator's method of achieving equivalent safety are required.

§75.1909(b)(8):

Q. The Wagner 3-1/2 has failsafe brakes built into the transmission. It also has a redundant failsafe brake system built into the service brake system that traps a column of oil to the wheel units. This system is in addition to one that would be acceptable on its own. Would you require that we remove the second system?

A. Yes. Systems that trap a column of fluid to hold the brake on have been found to bleed off and release the brake. Further, this brake is typically easier for the operator to apply than the supplemental brake required by the rule. These features pose an unacceptable safety risk. The rule specifically prohibits this type of added brake.


§75.1909(c):


Q. We modified machines so that they could not be started if the park brake had been manually released. This was something that was not mentioned before.

A. If the supplemental (park) brake required on heavy duty equipment is released by the handpump, the brake must automatically reapply when the machine is restarted. Alternatively, a means that prevents the machine from being restarted until the brake is manually applied is acceptable. We took the requirements for this brake system from the requirements in section 75.523-3 for electric-face equipment. The requirement that the brake reapply on restarting the machine is consistent with the enforcement of section 75.523-3.

Q. We will have to remove our existing construction/utility tractor and replace it with a Ford tractor with an approved engine. Norbert Paas is trying to get approval for the New Holland model 201 engine. The tractors that are currently available have a model 192 engine so we will have to change the engine, provided Mr. Paas is successful. We feel we should petition the front brake requirement for these tractors to address concerns of reduced steering capability that will result if we install front brakes. Should we go ahead and purchase the tractor with the correct engine?

A. We see no diminution of safety in requiring front brakes on tractors. Unlike graders, front brakes on tractors will provide a significant braking force. Also, if equipped with a bucket or forks, additional weight on the front wheels will make front brakes more important. We do not see a justification for a petition in the case of tractors.

§75.1910(b):


Q. In Oct. 1998, MSHA made a courtesy inspection on some upgraded equipment. Everyone was led to believe that a 600-amp fuse would be sufficient in most starting circuits. We were also led to believe that master disconnects with ratings of 175 continuous amps and 1000 amps intermittent for 15 seconds would also be acceptable. Please explain.

A. To clarify any misunderstandings or incorrect information we are including fuse/circuit breaker information on our homepage. We will also include a listing of switches that meet the regulation.

Q. Why are these breakers required on equipment approved by other Agencies for highway use? Also, the OEM designed the ignition system on a Dodge pickup equipped with a Cummins engine to fit the starting of this equipment. Why is that system not acceptable under the diesel rules?

A. We do recognize that commercial pickup trucks that meet DOT and SAE requirements often provide the safety required by the diesel regulations. We have noted in the new Compliance Guide that the OEM designed brake pedal assembly, the wire size, the wiring protection, the insulation of wiring terminals outside the engine compartment, and the vehicle's OEM installed fusing meets the regulations. However, OEM's do not design these vehicles for use in coal mines. Some features of these vehicles present fire risks that may be acceptable when they are used on the surface are unacceptably high when they are used underground. All unfused wiring, such as in the starting circuit on these vehicles, poses an unacceptable fire risk.

Q. Sometime about July we were informed that MSHA had determined a 2,000 amp master disconnect of the same configuration as we had been using was now required. After installing one of these larger amp disconnects we learned they would not be sufficient. Please explain.

A. You must use a switch rated for the current it will see during operation of the machine. It must also be rated to open under the maximum load it is likely to see. The best way to determine if the switch is adequate for the circuit is to determine if it can operate up to the time vs. current curve of the fuse/circuit breaker. We will list acceptable switches on our homepage.

.Q. We were told that we must install the fuse after the master disconnect instead of before (switch installed between battery and fuse). Please explain?

A. This is not a requirement. The rule requires that both the fuse and the disconnect be as close as practical to the battery. We have been recommending that the disconnect be placed between the fuse and the battery to allow personnel to change the fuse with no power to the fuse terminals. We consider this a reasonable recommendation to improve safety where there is not a clear requirement in the rule. The mine operator can choose the order of these components. Also, as discussed during the 9/28/1999 Utah Coal Association meeting: for pickup trucks that come from the OEM with dual batteries and have one battery on each side of the engine compartment, only one disconnect is needed and they will accept only one. We will include possible arrangements for the fuse and switch installations on these pickup trucks on our homepage. For all other vehicles, the single disconnect switch must deenergize all power conductors.

Q. Why doesn't MSHA approve breakers while they approve the engines?

A. This is an excellent suggestion. Although we will have to depend on the cooperation of the engine approval applicant to permit starter circuit testing, we do see this a practical way to get data for the selection of fuses/circuit breakers. In the short term, however, testing will have to be done on engines at mine sites, rebuild shops, and fuse/circuit breaker suppliers.

Q. You did not test circuit breakers until mid-September, they are back ordered, they are not in stock, and until now the fuse location and disconnect switch type were unresolved. How are operators to comply with the 11/1999 date?

A. Fuses can be used if no circuit breaker is available. As we evaluate circuit breakers, fuses, and switches we will list them on the MSHA homepage. We welcome requests for evaluations of specific devices.

Q. We were informed that we needed to change to a 125, 150, or 175 amp fuse and proper size fuse holder which is about five times as large as the 600 amp fuse. What is required?

A. We list acceptable fuses on our homepage.

Q. When is MSHA going to approve more breakers?

A. We have prepared a technical paper on how to determine the current draw of the starting circuit and how to select a fuse or circuit breaker to protect the circuit as required by the rule. Although determining the current draw of the starting circuit requires specialized equipment and knowledge, the industry can perform the procedure. It is not an approval program. At least one equipment manufacturer is performing these tests. We are planning several more tests in the next couple of weeks. We will continue to update our homepage with fuse and circuit breaker information.

§75.1910(c):


Q. We were told that a circuit breaker is required in the alternator circuit. This was not previously stated. Please explain.

A. You must provide all wiring with a fuse or circuit breaker to reduce the risk of fire. Section 75.1910(e) specifically requires that charging generators be protected by a fuse/circuit breaker.

§75.1910(d):


Q. The master disconnect must be located as close as practical to the battery. Please explain.

A. The rule specifies this in the §75.1910(d). The rule, however, does not specify a distance but the fuse is typically installed within 18" of the battery. Again this is not a distance specified by the rule. However, unlike the location of the manual fuel shutoff valve where we recognize that accessibility is as important as how close it is to the fuel tank, for the disconnect switch the distance it is from the battery is more important, from a fire risk consideration, than its accessibility. We, therefore, require the switch to be as close as practical to the battery even if it is under a hood or cover.

Q. In March 1999, MSHA made another courtesy inspection and while they made a training video. At this time no mention was made that a larger master disconnect was needed, so we continued to use the same ones used in Oct. Please explain.

A. We did not evaluate the specific rating of the switch during this inspection. We will include a list of disconnects that meet the requirements of the rule on our homepage.

Q. We have used battery shut off switches for years, without problems. When the new rules came out, we selected a switch which was larger than the switch we had been using. MSHA originally accepted this switch. We bought about 100 of these switches, only to find that MSHA has changed its mind and determined they are not acceptable. If the rule is in fact performance based, wouldn't the switch we originally used be acceptable and one with higher protection be acceptable as well?

A. Section 75.1910(d) requires the switch to "be designed to operate within its electrical rating without damage." If the switches you are using meet this performance requirement then it is acceptable. We are relying on the switch manufacturer to provide rating information and have found that obtaining this information is difficult. We will accept technical switch rating information from other than the switch manufacturer. We do not, however, consider usage information acceptable. Please contact Arlie Massey, 304-547-2027, on the specific disconnect in question.

§75.1910(i):


Q. Nothing was mentioned about insulating each individual electrical terminal so that there could be no accidental arcing between hot terminals. Please explain.

A. The rule requires that all ungrounded conductors, including terminals be insulated. The new Compliance Guide, pg.7, also covers this requirement.

§75.1911:


Q. The fire suppression system required in §§75.1911 and 75.1912 is required to meet the manufacturer's specifications. Why are MSHA inspectors specifying how many nozzles, sensors, etc. are required? Shouldn't that be left to the system manufacturers? If we follow the direction of these inspectors, aren't we then violating this rule?

A. Fire suppression system manufacturers require that a fire risk analysis be performed to choose the correct system, the quantity of suppressant agent, the location of the nozzles, the location of the sensor wire, etc. Inspectors have been instructed to evaluate the installation of the system to ensure it addresses all of the hazards. Inspectors have also been instructed that a fire risk analysis performed by a person knowledgeable in this area, such as an authorized fire suppression system distributor, and detailing how they installed the system should be accepted instead of reevaluating the risks. In the absence of this documentation and, if the Inspector considers that not all hazards have been addressed, the system will be considered in noncompliance. To cover the additional hazards, you may need a larger system.

Q. We have limited availability to fire suppression system suppliers due to high demand. How are operators to comply with the 11/1999 date?

A. We published the §75.1911 requirements in 1996. They do not pose any unique problems for installation. These types of systems are common. For permissible machines the PIB does provide for an extension of the compliance date.

§75.1911(b):


Q. What is the definition of an exposed brake?

A. An exposed brake is a brake in which the friction surfaces are not totally enclosed. These surfaces reach temperatures that can ignite combustible fluids used on the machine. Wet disc brakes are not exposed brakes.

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