30 CFR Part 7, Subpart E -- Diesel engines intended for use in underground coal mines
Q. What does an engine manufacturer need to do to get an existing diesel engine approved under new subpart E in part 7?
A. In order to obtain MSHA approval for an existing engine under subpart E of part 7, the engine manufacturer must submit specific information to MSHA, including engine drawings, details on engine combustion, timing, etc., and the results of the tests and examinations required under subpart E. MSHA will expedite the processing of part 7 approvals for existing engines in machines currently in use in underground coal mines.
Q. If a manufacturer applies for MSHA approval under subpart E of part 7 for an existing engine that already has a minimum ventilating air quantity specified on its approval plate, and the minimum air quantity calculated under the part 7 test is different from what is already on the approval plate, will the approval plate itself be replaced or modified to reflect this change?
A. Permissible diesel-powered equipment approved under part 36 currently has an approval plate that lists a minimum ventilating air quantity. As of November 25, 1997, all part 36-approved machines must have a minimum ventilating air quantity determined in accordance with subpart E of part 7. MSHA has arranged to have part 7, subpart E tests conducted for four of the engines that are the most widely used on part 36-approved equipment and a revised minimum ventilating air quantity determined. The revised air quantities for these four engines will be available on the Internet at MSHA's Home Page
(http://www.msha.gov/S&HINFO/DESLREG) or by contacting MSHA's Approval and Certification Center at (304) 547-2051.
If the minimum ventilating air quantity calculated under part 7 is different from what is already specified on the approval plate, a new approval plate must be obtained. Equipment manufacturers should distribute new approval plates with the revised quantities to owners of this equipment.
All nonpermissible engines must be approved under part 7 as of November 25, 1999, and have a minimum ventilating air quantity determined as part of the approval process, which must be displayed on the engine approval plate. Nonpermissible engines approved under now-revoked part 32, which may have an approval plate displaying an air quantity determined under part 32, do not comply with this requirement, and must be approved under part 7 and display a part 7 approval plate by the 1999 deadline.
Q. Will engine testing conducted under part 7 be open to the public?
A. The final rule does not give the public a right to witness the engine tests. However, there is nothing to prevent the manufacturer from opening the testing to the public, if it chooses to do so.
Q. Why does MSHA require methane to be added to the intake air during testing of category A engines under part 7?
A. Category A engines must be designed to operated safely in face areas and return air courses where methane may be present. Thus, Category A engine testing is performed with 1.0 percent methane injected into the intake air. The methane acts as additional fuel in the engine, which affects the fuel-to-air ratio. This change in fuel-to-air ratio increases emissions levels, especially carbon monoxide and oxides of nitrogen.
Q. Under the final rule, how will diesel engines approved under part 7 be identified? Is it acceptable under the new regulations if the approval plate on existing equipment is located in the operator's compartment?
A. Diesel engines approved under part 7 will display an approval plate to indicate their approved status and also to indicate the minimum ventilating air quantity for that engine. Part 36 equipment that is equipped with a power package approved under part 7 will have three approval plates: one on the engine indicating that it has been approved under subpart E of part 7; one on the power package indicating that it has been approved under subpart F of part 7; and one on the machine (which will generally be located in the operator's compartment) indicating that the equipment has been approved as a fully assembled machine under part 36. This equipment will have an approval number that begins with 36c-. Existing part 36 equipment (which would not have a power package approved under new subpart F of part 7) will have an approval number that begins with 31- that is displayed on a single approval plate, which may continue to be located in the operator's compartment.
Q. What if the approval plate is on the engine, and the mine operator moves that engine to a different piece of equipment?
A. If the approval plate reflects a part 7 engine approval and is moved into a different piece of nonpermissible equipment, the approval plate should remain on the engine. Before a new engine is installed in a part 36-approved machine, the mine operator must ensure that the engine has been approved for use in that machine. This information may be obtained either from the equipment manufacturer or from MSHA's Approval and Certification Center.
Q. Does the final rule allow existing part 36 engines to be used until the end of their useful life? With regard to nonpermissible (outby) equipment, if an engine is sent out to be rebuilt, which requirements must it meet?
A. Engines in existing part 36-approved equipment may continue to be used in underground coal mines. However, the revised part 36 minimum ventilating air quantity is applicable unless and until the equipment engine has been approved under part 7 and displays a new part 7 approval plate obtained from the manufacturer. Engines in nonpermissible diesel-powered equipment must be approved under subpart E of part 7 by November 25, 1999. After that date, nonpermissible engines must be rebuilt to approved condition, meeting the specifications of subpart E of part 7.
Q. Will existing part 32 engines meet the part 7, subpart E, category B requirements when the requirements take effect on November 25, 1999?
A. Existing part 32-approved engines may continue to be used in equipment operating in underground coal mines after November 25, 1999 only if the engine manufacturer obtains formal MSHA approval under subpart E of part 7. As a practical matter, drawings from the part 32 approval may be used by the engine manufacturer in obtaining part 7 approval if the drawings are representative of the current version of the engine. Additional testing will be required under part 7, however, to determine the engine's particulate index and gaseous emissions.
Q. We have a number of parts drawings which apply to Schedule 24" equipment bearing the notation . . . must not be changed without approval by MSHA. Is it correct to assume that this notation can be ignored?
A. Yes. That notation no longer has any significance. Part 31 (so-called Schedule 22") and part 32 (so-called Schedule 24") were revoked by the final rule and no longer exist as MSHA regulations. MSHA has stopped processing new approvals and will no longer consider changes to approvals issued under these two parts.
A part 31 or 32 approval plate does not give a machine any special status. Specifically, part 31-approved permissible locomotives are not permitted in areas where permissible electrical equipment is required. Equipment in those areas must now have a part 36 approval.
MSHA, however, will retain all part 31 and 32 approval records to assist other government agencies, whose regulations may reference either part, in determining if certain machines still meet the conditions of approval.
Q. If an engine has been approved under subpart E of part 7, is it acceptable for a mine operator to remove the approval plate until November 25, 1999?
A. Under §75.1907(b)(4), equipment approved under part 36 must have a particulate index and a dilution air quantity determined in accordance with subpart E of part 7 by November 25, 1997. If part 36-approved equipment has been provided with an engine approved under part 7, the approval plate should remain on the engine to indicate that this requirement has been satisfied. Nonpermissible equipment is not required to be provided with part 7-approved engines until November 25, 1999, and minimum ventilating air quantities will not be required for nonpermissible equipment until that requirement takes effect in 1999. In the meanwhile, nothing in the final rule would prohibit the removal of the approval plate on nonpermissible equipment. MSHA, however, does not encourage this practice.
30 CFR Part 7, subpart F -- Diesel power packages intended for use in areas of underground coal mines where permissible electric equipment is required.
Q. Will the requirements for §7.98(j) for non-sparking starting mechanisms require a field modification or SNAP on some existing equipment? If so, a bronze starter gear may not be available for all current equipment. Are there other alternatives?
A. No. Under the final rule, existing equipment already approved under part 36 is not required to be retrofitted to comply with the power package requirements of part 7, subpart F. As no retrofit is needed, no field modification or SNAP is needed. As a practical matter, many of the component systems on existing part 36 equipment already meet the new requirements in part 7, subpart F.
For diesel equipment manufacturers who may wish to convert the design of the certified component systems on existing part 36 equipment to comply with the new permissible power package requirements, there is an alternative to the bronze starter gear specified -- an automatic interlock in the starting system to prevent engagement of the starter while the engine is running.
Q. Are there any requirements for existing part 36 equipment that may require equipment alterations or retrofits to comply with the new regulations?
A. New requirements that do apply to existing part 36 equipment, and which may therefore necessitate equipment retrofits, are set forth in
§75.1907(b). Paragraph (b)(1) requires that, as of April 25, 1997, this equipment have a safety component system that limits surface temperatures to those specified in subpart F of part 7 (i.e., 302 °F, 150 °C). All part 36 equipment used in underground coal mines already meets this requirement, so no retrofit or other action by the mine operator is needed.
Paragraph (b)(2) requires existing part 36 equipment to be provided with a manual or automatic fire suppression system that complies with
§75.1911 by November 25, 1999. Section 75.1911 requires that fire suppression system actuation shut off the engine. Some changes to the safety shutdown system may be required to allow this, which will require a SNAP or a field modification However, some manufacturers have already built this option into their certified component systems. In these instances, mine operators can make the modification to comply with the §75.1911 requirement. Existing
§75.342 has also been revised to require methane monitors on certain types of diesel-powered equipment by April 25, 1997, which will require similar modifications to the safety shutdown systems. Again, some safety component manufacturers have already had this option evaluated and offer systems with the optional shutdown capability. If this is not the case, some form of MSHA review or approval would be required. MSHA encourages equipment manufacturers to apply for extensions of approval for part 36 equipment and to include the shutdown feature for the fire suppression system and methane monitor as options in applications for approval of power packages under subpart F of part 7.
Paragraph (b)(3) requires existing part 36 equipment to be provided with a braking system that meets specified requirements in
§75.1909 by November 25, 1999. Most existing Part 36 equipment is already equipped with brakes that meet these requirements.
Paragraph (b)(4) requires that, effective November 25, 1997, a particulate index and dilution air quantity, in accordance with subpart E of part 7, be determined for part 36 equipment that is manufactured before November 25, 1999.
Paragraph (b)(5) does not apply to existing part 36 equipment.
Finally, existing regulations at §§75.1710 and
75.1710-1 have been revised to require cabs or canopies on diesel-powered face equipment no later than April 25, 1997. Cabs and canopies are not subject to MSHA approval and may therefore be added to diesel-powered equipment without Agency action.
Q. Is there any overspeed protection provided in power packages under this subpart?
A. There is no requirement for automatic overspeed protection. However, an equipment operator has the ability to manually shut down equipment with an intake air shutdown device in addition to the normal fuel shutoff, if necessary.
Q. Isn't there a potential to blow head gaskets if the intake air shut-off valve closes while the engine is running?
A. There is a potential to damage the engine if the intake air shutdown device, which is designed to be closed in the event of an emergency, is activated while the equipment engine is running. However, the risk of equipment damage is offset by the protection provided by the operation of the emergency safety device, which is designed to stop the engine and serves as a backup in the event that the normal fuel shutoff mechanism fails.
For purposes of weekly equipment maintenance, a test procedure has been developed that will allow the emergency shutdown device to be checked without causing engine damage. This test procedure is set forth below.
Emergency Intake Air Shutoff Test Procedure
Warning: The following test procedure must be followed to test the operation of the emergency intake air shutoff valve. Failure to follow this procedure can result in extensive damage to engine components and personal injury.
If a diesel particulate filter and high exhaust gas temperature sensor are installed, remove the sensor and filter element. Failure to do so can result in damage to the sensor and may result in the ignition of the filter element.
1. Shut off the water make-up supply.
2. Drain the scrubber by removing the drain plug.
3. Disconnect the pressure line to the scrubber float valve and plug. Start the engine.
4. Operate the engine at full throttle until no water remains in the scrubber (water stops draining from the drain port).
5. Release the engine throttle allowing the engine to idle.
6. Actuate the emergency air intake shutoff control. The engine must shut down immediately (engine speed must decrease continuously until the engine stops).
7. Replace the drain plug, reconnect the pressure line to the scrubber float, open the water make-up valve and refill the scrubber with water. Replace the high exhaust gas temperature sensor and diesel particulate filter, if applicable.
MSHA is working with manufacturers to modify their permissibility checklists to include this test procedure. MSHA has already worked with some manufacturers to modify checklists to address this concern and will work with others who submit applications for new approvals, or who wish to modify existing permissibility checklists.
Q. With respect to
§7.103(b)(3)), do all currently approved vehicles have exhaust gas temperature sensors? If not, will these require a field modification or SNAP?
A. Existing part 36 equipment does not need to be retrofitted to comply with the power package requirements in subpart F of part 7. No retrofit would be required, and therefore no SNAP or field modification would be needed. However, existing part 36 equipment may need to be retrofitted to comply with
§75.1907(b), which requires existing part 36 equipment to be provided with certain features by specified deadlines. These requirements are explained in more detail above.
Q. Section 7.97(a)(10) refers to a power package checklist which will be much more detailed than the checklist referred to in
§75.1914 relating to in-mine maintenance. Will MSHA clarify what checklist is contemplated for operator maintenance?
A. 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 specific items that should be covered during the weekly equipment examination required under §75.1914, and forwarded this information to manufacturers of the great majority of diesel equipment used in underground coal mines. MSHA intends that the scope of 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 MSHA for review and incorporation into their equipment's 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. This information is also available on MSHA's Internet Home Page, from MSHA district offices, and from MSHA's Approval and Certification Center.
MSHA has also prepared a generic weekly checklist that may be used to supplement existing permissibility checklists until they are revised, or in instances where a revised checklist may not be available. The generic checklist will be distributed shortly as an MSHA Program Information Bulletin, and will also be available on MSHA's Home Page.
30 CFR Part 36 -- Approval requirements for permissible mobile diesel-powered equipment
Q. Is there a maximum capacity for fuel tanks in permissible diesel-powered equipment?
A. The limit on fuel tank capacity for permissible diesel-powered equipment is the amount of fuel needed to operate the equipment at full load for approximately four hours.
Q. Will diesel-powered equipment previously approved under part 36 maintain its approved status, or will the equipment have to be reapproved under part 36 as it has been revised by the final rule?
A. Under the final rule, existing equipment already approved under part 36 is not required to be reapproved under revised part 36 or retrofitted to comply with the power package requirements of part 7, subpart F. However, certain modifications to part 36 equipment are required by the final rule, and some may require changes to the existing approval by the manufacturer or a field modification by the mine operator.
New requirements that apply to existing part 36 equipment, and which may therefore necessitate equipment retrofits, are set forth in
§75.1907(b). Paragraph (b)(1) requires that, as of April 25, 1997, this equipment have a safety component system that limits surface temperatures to those specified in subpart F of part 7 (i.e., 302 °F, 150°C). All part 36 equipment used in underground coal mines already meets this requirement, so no retrofit or other action by the mine operator is needed.
Paragraph (b)(2) requires existing part 36 equipment to be provided with a manual or automatic fire suppression system that complies with
§75.1911 by November 25, 1999. Section 75.1911 requires that fire suppression system actuation shut off the engine. Some changes to the safety shutdown system may be required to allow this, which will require a SNAP or a field modification However, some manufacturers have already built this option into their certified component systems. In these instances, mine operators can make the modification to comply with the §75.1911 requirement.
Existing §75.342 has also been revised to require, as of April 25, 1997, methane monitors on certain types of diesel-powered equipment, which will require similar modifications to the safety shutdown systems. Again, some safety component manufacturers have already had this option evaluated and offer systems with the optional shutdown capability. If this is not the case, some form of MSHA review or approval would be required. Existing regulations at §§
75.1710-1 have been revised to require cabs or canopies on diesel-powered face equipment by April 25, 1997.
Paragraph (b)(3) requires existing part 36 equipment to be provided with a braking system that meets specified requirements in
§75.1909. Most existing Part 36 equipment is already equipped with brakes that meet these requirements.
Paragraph (b)(4) requires a particulate index and dilution air quantity, in accordance with subpart E of part 7, to be determined by November 25, 1997 for part 36 equipment manufactured before November 25, 1999. As previously stated, this information is now available for four of the most widely used permissible engines, and MSHA expects that equipment manufacturers will provide new approval plates for these machines.
Paragraph (b)(5) does not apply to existing part 36 equipment.
Q. Does the surface temperature limit for equipment (302 °F) apply to engine components or to the entire piece of equipment, such as dry disc type brakes?
A. The surface temperature limit applies only to power packages and to the certified electrical components.
Q. Approval plates were not required on engines for equipment approved under part 36. How does a mine operator obtain approval plates for engines that are already in currently approved part 36 equipment?
A. The final rule does not require engine approval plates on currently approved part 36 equipment. New equipment approved under revised part 36 for diesel equipment used in coal mines will incorporate power packages approved under subpart F of part 7, which will be provided with engine approval plates.
Mandatory Health Standards
Section 70.1900 -- Exhaust gas monitoring
Q. Section 101(c) of the Mine Act allows modification of safety standards, but not health standards. The exhaust gas monitoring requirements in this rule are published as part of MSHA's mandatory health standards under part 70. Therefore, a modification of this standard would not be allowed. Does MSHA plan to move these requirements and include them with the mandatory safety standards in §75.325 so a petition can be filed?
A. Section 70.1900 provides for the monitoring of CO and NO2, gaseous components of diesel exhaust that can adversely affect miners' health. These requirements are properly published with other MSHA health-related standards in part 70. As specified by the standard, flexibility is provided to accommodate the different operations and ventilation systems at individual mines. MSHA has no plans to move these requirements to part 75.
The required on-shift measurements of CO and NO2 provide a check on all of the systems put in place to provide reasonable assurance that miners are not overexposed to diesel exhaust gases. The final rule allows a mine operator to obtain approval for a higher action level if the mine operator can establish that a higher action level will maintain continuous compliance with applicable TLV's.
Q. Does any of the sampling required by state agencies satisfy the exhaust monitoring requirements of the final rule?
A. Some states require sampling of diesel-powered equipment at a specified distance behind the equipment tail pipe. This type of sampling does not comply with the requirements of the final rule. However, if a state exhaust monitoring requirement is essentially identical to the requirements of the final rule (in the location, frequency, and method of sampling), this monitoring would be accepted by MSHA as compliance.
Q. Is exhaust gas monitoring required in all areas of the mine where diesel-powered equipment is operated?
A. No. Under §70.1900(a), exhaust gas monitoring is required: in the return on each section where diesel-powered equipment is used; at the loading point of the section if diesel haulage equipment is used; and inby the last piece of diesel equipment on the longwall face where equipment is being installed or removed. However, the district manager has the authority to designate additional areas for monitoring if necessary. These additional areas will be identified in the mine's ventilation plan.
Q. Why does the final rule require a CO and NO2 reading once each shift at the section loading point? For mines using belt air at the face, why would the return air sample not suffice for this requirement?
A. The final rule requires exhaust gas monitoring at the section loading point because it is an area where exhaust gases can easily accumulate to excessive levels during dumping operations.
Q. What criteria will be used by district managers in establishing additional sampling points?
A. The intent of the rule is to allow designation of additional sampling points where miners are at risk of being overexposed to gaseous diesel contaminants. Areas where this may be a concern, such as refueling locations and construction sites, could be designated as additional sampling locations by the district manager.
Q. Is there a specific point during the shift when the on-shift monitoring of exhaust gases must be conducted?
A. The final rule provides that exhaust gas monitoring may be done at any time during the shift, so long as the sample is collected during periods that are representative of conditions during normal operations. MSHA intends that these tests be made when diesel-powered equipment is being used as it typically is during the mining process. This means, for example, that sampling would be appropriate when diesel haulage equipment is moving coal or diesel-powered roof bolters are installing bolts.
Q. If more than one unit of diesel-powered equipment is operating on a section, how is an exhaust gas check conducted that is representative, as required by §70.1900(b)(3)?
A. The purpose of the monitoring requirements is to gauge the performance of the diesel exhaust control system under normal operating conditions. MSHA intends that tests for carbon monoxide and nitrogen dioxide be made when diesel-powered equipment is being used as it typically is during the mining process. The exhaust gas check may therefore be made at a different time in the shift than during the on-shift examination conducted under §75.362.
Q. Is there a specific location in the air stream or entry where the samples must be taken?
A. The exhaust gas monitoring required under the final rule is intended to check the entire system of diesel exhaust control, not just the quality of the exhaust from an individual machine. Consequently, the sample should be taken in a location where the exhaust gases have mixed with the mine atmosphere and where the sample will be representative of the diluted diesel exhaust.
Q. Is more than one sample required during a shift if additional diesel-powered equipment is operated after a sample has already been taken?
A. If additional equipment is brought into the section for more than a quick excursion, such as to bring supplies up to the section, it may be necessary to take another sample, to ensure that the sample is representative of the equipment being operated on the section during that shift. For example, if the check is made while three ram cars are being operated on the section, and a fourth ram car is brought up to the section and operated along with the other three, another check probably needs to be made. If the equipment operation will have an impact on miners' exposure to diesel contaminants, another check should be made.
Q. If diesel-powered equipment, such as a forklift, is being used on the section in addition to electric haulage equipment, is exhaust monitoring required?
A. The answer to this question depends on whether the diesel-powered equipment goes inby the loading point. If the diesel equipment does not go inby the loading point, sampling would be necessary only if it is required as an additional sampling point by the district manager under §70.1900(a)(4), and specified in the ventilation plan.
Q. If a mine has a split ventilation system, does the final rule require exhaust gas monitoring on each section?
Q. If equipment is operated inby the feeder, is the equipment still considered section equipment?
Q. If a unit of diesel-powered equipment goes inby the tailpiece, but not inby the last open crosscut, does the final rule require exhaust gas monitoring in the immediate return?
A. In this situation, the final rule requires exhaust gas monitoring in the immediate return.
Q. At what location should exposure monitoring be conducted on the inby side of a longwall recovery operation?
A. Exposure monitoring should be conducted as far inby of the equipment as possible. It should be noted that this would not necessarily be inby the recovery site.
Q. If the equipment can be excluded from the air quantity calculation in
§75.325, can the equipment be excluded from the exhaust gas monitoring requirements of §70.1900, when it would only be running for a couple of hours a day?
A. No. Under the final rule, if diesel-powered equipment is being used inby the section loading point, exhaust gas monitoring is required on the section on that shift. The purpose of the exhaust gas monitoring required by the final rule is to check the entire system to ensure that diesel exhaust gases are being controlled and are not causing overexposure to miners.
It should be noted that the final rule does not require exhaust gas monitoring of equipment used outby the section, unless the outby location is identified for exhaust gas monitoring by the district manager and specified in the mine ventilation plan.
Q. What are the requirements for exhaust gas monitoring for diesel-powered equipment operated in outby areas?
A. The final rule does not specifically designate outby areas for exhaust gas monitoring. However, the district manager has the authority to require sampling in other areas, including outby areas, if necessary. These additional areas are required to be specified in the mine ventilation plan. Outby equipment would be required to have an exhaust gas check only if the district manager has designated that in the ventilation plan as a place to sample. It is important to note that the exhaust gas monitoring required by §70.1900 is not checking the emissions of the machine, but the effects of diesel emissions on the mine atmosphere.
Q. Is exhaust monitoring required on the longwall face if a diesel-powered scoop is being operated there?
Q. The final rule requires exhaust monitoring to be conducted by a certified person. What is the definition of a certified person?
A. Section 70.1900(a) requires that exhaust gas monitoring be conducted by a certified person as defined by §75.100. A certified person under §75.100 is a person who has been certified as a mine foreman (mine manager), an assistant mine foreman (section foreman), or a preshift examiner (mine examiner), either by the State in which the coal mine is located, or by the Secretary of Labor.
Q. Does the final rule require exhaust monitoring on shifts when no diesel-powered equipment is being operated on the section?
A. No. Exhaust monitoring of the section is not required during shifts when no diesel-powered equipment is operating.
Q. May bottle samples be used to satisfy the exhaust monitoring requirements of this section?
A. No. Section 70.1900(b)(1) specifically requires that exhaust monitoring results be available immediately to the person collecting the samples. Results of bottle samples are not available immediately, and are typically sent to a laboratory for analysis. Use of bottle samples would therefore not comply with this requirement.
Q. Must the monitoring device be an instantaneous read-out device, or can it be one that samples over an 8-hour period?
A. The monitoring device must give immediate results to the individual taking the measurement. The device can sample over an 8-hour period if the current gas concentration can be determined as an instantaneous reading at the time the gas check is being made.
Q. Can existing atmospheric monitoring systems (AMS) be used to satisfy the exhaust gas monitoring requirement?
A. Yes, provided that the sensors are located where the samples must be taken and the results are immediately available. This can be achieved if the sensor has a digital readout at the sampling location. The requirement could also be satisfied if the person conducting the monitoring calls out to the system control room for the CO and NO2 measurements at the appropriate sensors at the appropriate time.
Q. When referring to TLV™ levels in §70.1900, does MSHA mean the short term exposure limit (STEL), the ceiling level, or the TWA levels for an eight-hour period?
A. References to TLV™ in
§70.1900 mean 50 parts per million (ppm) for carbon monoxide (CO), which is the eight-hour limit, and 5 ppm for nitrogen dioxide (NO2), which is both the eight-hour and the ceiling limit.
Q. The final rule incorporates by reference the 1972 TLV™'s of the American Conference of Governmental Industrial Hygienists (ACGIH), which have been updated and revised several times since 1972. Why did MSHA not use the most recent edition of the TLV™'s?
A. The ventilating air requirements for diesel-powered equipment in the final rule are designed to maintain gaseous diesel exhaust contaminants to within permissible limits; that is, whatever MSHA air quality regulations currently require. The air quality standards that currently apply in underground coal mines are the 1972 TLV's, incorporated by reference in MSHA regulations at §75.322. If any of the limits for diesel exhaust gases are modified, MSHA would expect to undertake rulemaking to incorporate those changes into
§70.1900. MSHA also would expect to go through rulemaking to modify the levels specified in subpart E of part 7 to which gaseous contaminants must be diluted in determining a diesel engine's ventilating air quantity.
Q. Will MSHA issue citations when the action level is exceeded during exhaust gas monitoring?
A. No. Under the final rule, simply exceeding the action level would not be a violation and would not be cited. However, the final rule requires corrective action in response to a measurement over the action level. If corrective action is not taken, a citation would be issued.
Q. What types of appropriate corrective action would MSHA consider to be sufficient once the action level has been exceeded?
A. A properly designed ventilation system, along with effective equipment maintenance, should prevent the action level from being exceeded. If the action level is exceeded, then the flaw in the system needs to be identified and corrected. In instances where the action level has been exceeded, corrective action could include, but is not limited to:
Checking, and reducing if necessary, the number of diesel engines operating on the section or operating in the area;
Observing the operating diesel engines to determine if any are producing visible smoke, and performing corrective maintenance;
Checking to ensure that the ventilating air quantity is sufficient, and making necessary adjustments; and
Testing individual diesel engines to determine if any engine is producing high levels of exhaust gases as compared with the levels measured during previous maintenance checks.
MSHA anticipates that in almost all cases mine operators will discover an obvious cause, e.g., an engine in need of attention or a ventilation problem.
Q. Could immediately tak[ing] appropriate corrective action include personal sampling to determine whether the TLV's for CO and NO2 are being met?
A. MSHA would consider such sampling to be part of the operator's corrective action, as long as the mine operator intended to use the sampling results to support adjustment of the action level.
Q. Will some mines have a higher action level than other mines?
A. This is possible under the final rule. The rule allows mine operators to obtain approval for actions levels higher than the 50 percent action level specified in
§70.1900(c). The purpose of the action level is to ensure that miners are not being overexposed to gaseous diesel exhaust contaminants, by requiring corrective action before contaminant levels exceed maximum limits. A mine operator who wishes to have the action level raised above the 50 percent level must demonstrate that miners will not be overexposed to diesel exhaust contaminants at the higher action level.
Q. Over what period of time must a mine operator conduct personal sampling for diesel exhaust gases to obtain approval of a higher action level by the MSHA district manager?
A. The answer to this question depends on the specific circumstances in each case. The data submitted by the mine operator to support a higher action level should demonstrate that a higher action level will not result in overexposures to miners under all foreseeable mining conditions. Sampling should provide data representative of normal operating conditions sufficient to make an informed decision.
Q. What are the criteria that must be satisfied by a mine operator to be granted a higher action level?
A. In order for MSHA to approve a higher action level, the data must demonstrate that an increased action level will continue to ensure that miners are not being overexposed to gaseous diesel contaminants. If a mine operator can demonstrate that compliance with the TLV's is maintained at the same time that the gaseous contaminant levels in the return air course are greater than the 50 percent action level, the district manager may increase the action level.
Q. Who takes samples for CO and NO2 to support a higher action level, the operator or MSHA?
A. Typically, the mine operator will be requesting a higher action level, and it would be the mine operator's responsibility to supply information, such as sampling results, to support a higher action level. After evaluation of the operator's supporting information, MSHA may determine that Agency sampling is needed. Therefore, both the operator and MSHA may take samples as part of a request for a higher action level, depending on the specific circumstances in each case.
Q. When does the final rule require a record of the results of exhaust gas monitoring?
A. Results of exhaust gas monitoring are required to be recorded only if they exceed the applicable action level. Results that exceed the action level must be recorded because they indicate that there is something that needs attention, such as poorly maintained equipment or a ventilation system that is not functioning correctly. A record will alert mine management and miners that there is a problem. The final rule also requires that the record reflect the corrective action taken.
Q. Does the final rule specify where exhaust gas monitoring results must be recorded?
A. The regulations require that exhaust monitoring records be made part of and in the same manner as the records for hazards detected during the on-shift examination under
§75.363. This means that the records should be kept in the on-shift examination book.
Mandatory Safety Standards
Section 75.325 -- Air quantity
Q. Does the air quantity calculation under §75.325(g) include the approval plate air quantity of diesel-powered equipment operating outby the section?
A. The approval plate air quantity of equipment operating outby the section would not be included in the calculation for operating sections, because the multiple unit formula only includes equipment operating on the section. However, in areas where mechanized mining equipment is being installed or removed, equipment operating outby must be included in the initial calculation under paragraph (g) if it is ventilated by intake air on that split. If the equipment in fact does not significantly affect the exposure of miners to diesel exhaust, equipment may be excluded from the calculation under paragraph (h)(4). The equipment exclusion must be approved by the district manager and specified in the ventilation plan.
Q. Under the final rule, where must air quantity measurements be made in outby entries?
A. The final rule specifies where these measurements are to be made in §75.325(f)(3) and (4). In areas of the mine developed prior to April 25, 1997, the minimum ventilating air quantity must be maintained in any air course with single or multiple entries where the equipment is being operated outby the section loading point. Therefore, air quantity measurements are to be made in all the common entries, and the total air quantity in all the entries must be at least the minimum air quantity. These measurements can be performed anywhere along these entries. In areas of the mine developed on or after April 25, 1997 air quantity measurements may be made anywhere in the entry. The air reading should be taken without the equipment being present in the entry so that a determination is made of the normal airflow.
Q. Does the final rule require the adding together of the approval plate air quantities of multiple units of diesel-powered equipment in outby entries?
A. The minimum ventilating air quantity in an entry outby the section loading point would be the approval plate air quantity of the machine with the highest quantity. If all three units have the same approval plate quantity, one single unit approval plate quantity is required. This air quantity is not included in the minimum ventilation air quantity required on the working section.
However, the approval plate air quantity of equipment working outby will be included in the minimum air quantity calculation if the equipment is being operated in an area where mechanized mining equipment is being installed or removed.
Q. Before the final rule went into effect, ventilation plans typically took the 100-75-50" approach for ventilating diesel-powered equipment, meaning that minimum ventilating air quantities were calculated by using 100 percent of the greatest equipment approval plate quantity, 75 percent of the next highest, and 50 percent of all other equipment approval plate quantities. The final rule now requires 100 percent of all approval plate air quantities. Was there a problem with the old system?
A. The new formula in the final rule recognizes that approval plate air quantities are calculated differently under part 7 than they were under part 36 prior to the promulgation of this final rule. Under subpart E of part 7 an engine's approval plate air quantity will be determined by the amount of air needed to dilute gaseous diesel exhaust contaminants (CO, CO2, NO, and NO2) to permissible limits. Up until the final rule, approval plate quantities were determined by the amount of air needed to dilute contaminants to 50 percent of the limits that were in effect when part 36 was first promulgated in 1961. Although the levels to which CO and NO2 must be diluted remain the same under the final rule, the dilution levels for NO and CO2 are twice as high. Consequently, less air will be needed to dilute these two gases to the higher levels, and the approval plate quantity will be lower under part 7 for most if not all engines. However, the approval plate quantity will now directly correspond to the applicable contaminant limits. It follows that 100 percent of the approval plate quantity, rather than some fraction thereof, must be provided to adequately dilute the gaseous diesel contaminants.
Q. If a diesel-powered machine is equipped with technology that reduces exhaust emissions, will MSHA take this into account and calculate a reduced approval plate air quantity?
A. MSHA will consider the effectiveness of exhaust gas controls in setting the engine's approval plate air quantity, provided that the device is integral to the engine design and is part of normal production engines.
Q. If a device that reduces exhaust emissions is available and is installed on a diesel-powered machine, may this information be used as the basis for excluding the equipment's approval plate air quantity under §75.325(h)(4)?
A. If diesel-powered equipment is provided with a device that reduces exhaust emissions, this may provide the basis for excluding the equipment's approval quantity under §75.325(h)(4). It should be noted, however, that equipment's approval plate air quantity may only be excluded from the air quantity calculation for multiple units of equipment under §75.325(g). The final rule does not provide for exclusion for single units of equipment.
Q. How will the requirements for minimum ventilating air quantities in outby areas be enforced during the 3-year. phase-in of the approved engine requirement, when some engines may have approval plate air quantities determined under part 7 subpart E, and some will not?
A. Nonpermissible equipment is required to be provided with an engine that has been approved under subpart E of part 7 and which has had a minimum ventilating air quantity determined and displayed on an approval plate no later than November 25, 1999. Until that deadline, the ventilation requirements for diesel-powered equipment in §75.325 will apply only to permissible equipment approved under part 36.
Q. For longwall installations and removals, what is the "area" where the minimum ventilating air quantity must be maintained and what outby haulage equipment, such as locomotives, would be considered to be in the area during longwall moves, and thus included in the air quantity calculation?
A. This means that all diesel-powered equipment (consistent with the phase-in schedule) operating in the intake air split of the longwall panel, because it contributes to miners' exposure to diesel exhaust emissions, must initially be included in the ventilating air quantity calculation for longwall installations and removals. The final rule would then allow for exclusion of individual pieces of equipment if they do not significantly affect the exposure of miners.
Longwall installations and removals are typically periods when diesel equipment is working continuously under load in a confined area, and where diesel exhaust emissions are particularly high. In such a situation, all equipment that has the potential to contribute to miners' exposure to contaminants must be considered initially. If there are legitimate grounds for certain pieces of equipment working in the area to be excluded from the calculation, mine operators should seek such an exclusion from the district manager.
Q. What is the required minimum ventilating air quantity in multiple entries?
A. In areas of the mine developed on or after April 25, 1997, the minimum air quantity would be required in the entry where the equipment is being operated. In areas of the mine developed before April 25, 1997, the minimum air quantity must be provided in the air course. Where there are multiple common entries, the sum of the air quantity in all the common entries must be at least the minimum quantity.
Q. Is the approval plate air quantity required at the section loading point only if the equipment being used is in the production mode?
A. No. Section 75.325(f)(2) requires that the approval plate air quantity be maintained at the section loading point during any shift that the equipment is being operated on the working section. This provision responds to concerns that loading points are one of the locations where excessive levels of diesel contaminants are a particular problem. Whether or not the mine is in the production mode is irrelevant.
Q. If diesel-powered equipment performs loading work, what does the final rule require as the minimum ventilating air quantity for this equipment?
A. A determination of the minimum ventilating air quantity for individual units of diesel-powered equipment depends on where the equipment is being operated, not the work the equipment is performing. If the equipment is operating in a working place, the approval plate air quantity
is required in that working place. If the equipment is operated on the working section, the approval plate air quantity would be required as the minimum ventilating air quantity at the loading point.
Q. If a belt move is taking place, where is the loading point?
A. During a belt move the loading point is in the process of being moved, and therefore there would be no loading point for purposes of the ventilating air quantities required by §75.325(f)(2). Consequently, the minimum ventilating air quantity would be required in that location only after the loading point has been set up and production has resumed.
Q. Has the agency considered what effect the increased ventilating air quantities required by the final rule are going to have on dust control, specifically dust scrubbers on continuous mining machines?
A. As a practical matter, the ventilating air quantities required by the final rule for diesel-powered equipment should not present such a problem. Only one diesel-powered machine will typically be behind the continuous miner at any given time, and the minimum ventilating quantity of air for that machine will be less than 10,000 cubic feet per minute, which is an air quantity that commercially available dust scrubbers can handle.
In some cases, the air quantity necessary to adequately ventilate diesel haulage equipment might not be consistent with the discharge quantities of the scrubber currently in place at a particular operation. If a mine operator elects to use diesel face haulage in conjunction with a scrubber for the continuous miner, the systems should be compatible.
Other conventional dust controls can be used should the quantity of air be incompatible with dust scrubbers. These include the use of fan spray systems, the use of line curtain/tubing to within 10 feet of the face, or the replacement of the scrubber with a higher capacity unit. If a scrubber is utilized with an exhausting line curtain, the excess quantity of air may be directed so that it does not flow over the continuous miner.
It is not acceptable to forgo effective ventilation of diesel-powered equipment and the control of harmful diesel exhaust contaminants to accommodate the ventilation requirements of dust scrubbers.
Q. Ventilation of diesel-powered equipment in outby entries will vary depending on whether the equipment is in an entry that was developed before or after April 25, 1997. Does the final rule require mine operators to submit a mine map showing areas that had been developed as of April 25, 1997, to facilitate compliance with this provision?
A. No. The final rule does not require submission of a mine map showing that information.
Q. What is the definition for the term working place as is it used in §75.325(f)(1)?
A. The term working place is defined in §75.2 for purposes of part 75, and means the area of the coal mine inby the last open crosscut.
Q. How much ventilating air is required for a permissible diesel scoop in the return air course?
A. The minimum ventilating air quantity for a diesel-powered scoop operating in a return air course would be the approval plate air quantity of the scoop.
Q. Why will approval plate air quantities determined under subpart E of part 7 be generally less than the quantities determined under part 36?
A. Approval plate air quantities will be calculated differently under part 7, subpart E, than they had been under part 36 prior to the issuance of this final rule. An engine's approval plate quantity under the final rule will be determined by the amount of air needed to dilute gaseous contaminants to the TLV's in §75.322. Up until now, approval plate quantities had been determined under part 36 based on the amount of air needed to dilute gaseous contaminants to 50 percent of the TLV's that were in effect in 1961, when part 36 was first promulgated. Although the levels to which CO and NO2 must be diluted remain the same under the final rule, the dilution levels for NO and CO2 are twice as high. Consequently, less air will be needed to dilute these two gases to the higher levels, and the approval plate quantity will be lower for most, if not all, engines. However, the approval plate quantity will now directly correlate to existing TLV's.
Approval plate quantities may also be slightly lower than under old part 36, as a result of the revision in part 36 that requires engines to be tested with 1.0 percent methane into the engine air intake, rather than 1.5 percent methane that was used before the final rule went into effect. Because injection of methane into the engine increases engine emissions, the lower concentration of methane used under the final rule will require a lower quantity of air to dilute.
Q. Section 75.325(h)(4) provides for the exclusion from the air quantity calculation of other equipment having duty cycles such that the emissions would not significantly affect the exposure of miners. What are some examples of other equipment?
A. Equipment that may be eligible for exclusion includes equipment with a very small engine (less than 10 horsepower), or heavy-duty equipment that is operated infrequently, for very short periods of time, or when other diesel equipment normally operated on the section is shut down or not operating. An example of equipment that could be considered for exclusion is a supply vehicle that is driven up to the section, shut down and unloaded, started up and immediately driven off of the section. Equipment that is operated in a location so that its exhaust does not pass over miners could also be eligible for this exclusion. Other examples include a roof bolter that is always operating on the opposite side of the section in a fish tail ventilation system, and a lube unit that goes onto a section only to refuel the section equipment.
Q. How will MSHA distinguish between light-duty and heavy-duty applications in determining whether to include or exclude individual pieces of equipment in the air quantity calculations in §75.325(g)?
A. All diesel-powered equipment, either operating on the working section or in the area where mechanized mining equipment is being installed or removed, whether light-duty or heavy-duty, is initially included in the air quantity calculation under paragraph (g). Mine operators who believe there is a basis for excluding particular pieces of equipment from the calculation because of the way they are operated may seek to have that equipment excluded.
Section 75.342 -- Methane monitors
Q. What specific types of diesel-powered equipment are required to be equipped with methane monitors?
A. The final rule now requires methane monitors on diesel-powered . . . face cutting machines, continuous miners, longwall face equipment, loading machines, and other mechanized equipment used to extract or load coal within the working place. See, 30 CFR §75.342. Working place is defined in §75.2 as the area of a coal mine inby the last open crosscut. Loading machines would include scoops and other diesel-powered machines used to load coal from inby the last crosscut, but would not include clean-up scoops, consistent with the application of this requirement to electric equipment.
Q. Can you operate diesel-powered equipment in 1 percent methane?
A. This rule does not change existing requirements for action at specified methane levels, as set out in §75.323. The requirements of §75.323 apply equally to diesel-powered equipment and electric equipment.
Section 75.371 -- Mine ventilation plan; contents
Q. Do we need to address exhaust gas monitoring on outby diesel-powered equipment in the ventilation plan?
A. No. The final rule does not specifically require monitoring of outby equipment. However, the district manager has the authority to designate a sampling point in outby areas, which must be included in the approved ventilation plan. For more detailed guidance on the final rule and ventilation plan approval, see Chapter 8 of MSHA's Handbook on Ventilation System and Methane and Dust Control Plans.
75.1710 and 75.1710-1 -- Cabs and canopies
Q. What diesel-powered equipment is required to have canopies and cabs?
A. The final rule requires canopies or cabs on diesel-powered face equipment, including shuttle cars. A cab or canopy is required on diesel-powered equipment if the same type of electrically powered equipment is required to have one. MSHA approval is not required to add a canopy to permissible diesel-powered equipment.
Section 75.1900 -- Definitions
Q. If the section has a temporary fuel storage area, are the temporary fuel storage tanks required to be wheel-mounted?
Section 75.1901 -- Diesel fuel requirements
Q. How will the mine operator demonstrate compliance with the requirements for sulfur content and flash point? Will the mine operator be required to test the fuel?
A. The rule requires that, upon request, the mine operator provide to an authorized representative of the Secretary evidence that the diesel fuel purchased for use in diesel-powered equipment underground meets these requirements. A mine operator may provide documentation from the fuel supplier to demonstrate that the fuel's sulfur content complies with the standard. MSHA may also elect to have a sample of the diesel fuel analyzed in order to confirm the actual sulfur concentration. For further information about this subject, please refer to MSHA Program Information Bulletin No. P97-17, which addresses Documentation of Diesel Fuel Content.
Q. Will a single material safety data sheet (MSDS) or letter from a fuel supplier satisfy the requirement that the mine operator present evidence that the diesel fuel meets the sulfur and flash point specifications?
A. Yes, so long as the necessary information is included in either document that has been provided by the current fuel distributor. However, if, for example, the mine operator was to change fuel distributors, a new MSDS or letter would be necessary.
Q. Is the color of the diesel fuel indicative of the sulfur content?
A. The color of diesel fuel cannot be used as evidence that the fuel meets the sulfur content limitation. The Environmental Protection Agency (EPA) has advised MSHA that fuel coloration indicates only if a fuel tax has been paid.
Q. Additives are flammable by themselves. Can flammable fuel additives be used if they are registered by EPA?
A. The rule prohibits the use of additives if they have a flash point that is less than 100 °F. Under §75.1901(b), flammable liquids may not be added to diesel fuel used in diesel-powered equipment in underground coal mines. The intent of the rule is to prevent the use of additives that lower the flash point of the diesel fuel and to specifically prohibit the use of gasoline as an additive. Typically, EPA-registered additives do not contain flammable compounds.
Q. May alternative fuels be used in diesel-powered equipment in underground coal mines? For example, there is a new alternative fuel made up of up to 50 percent water and 50 percent naphtha. Would it be considered diesel fuel?
A. This rule covers commercially available diesel fuels meeting EPA on-highway fuel requirements. Anything classified as a diesel fuel by the EPA would be acceptable.
Q. Does Number 1 diesel fuel meet the requirements for sulfur content and flash point in paragraph (a)?
A. Number 1 diesel fuel would meet the requirements of paragraph (a), so long as the sulfur content is no greater than 0.05 percent and the flash point is 100 °F or greater. Some, but not all, Number 1 diesel fuel meets those two requirements, just as some, but not all, Number 2 diesel fuel meets those requirements.
Continue on to Part 2.