Fayette County Health Center
100 New Salem Road, Room 167
Uniontown, PA 15401
October 20, 1999

Richard E. Stickler, Director
Bureau of Deep Mine Safety
Fayette County Health Center
100 New Salem Road, Room 167
Uniontown, PA 15401

Dear Mr. Stickler:

The TAC has reviewed the impact of the new MSHA Part 7 Diesel Regulations and their effect on the existing Pennsylvania Article II-A. The Part 7 Diesel Regulations will become effective on November 25, 1999.

It has come to our attention during the review that the ventilating air quantities issued for diesel-powered equipment by MSHA under the new Part 7 regulations will be one half of the quantities issued under the current Part 32 and Part 36 regulations. This will happen due to the fact that MSHA will no longer use 1% methane in the ambient air during testing for outby diesel equipment, nor will they use 1.5% methane in the ambient air during testing of inby or permissible diesel equipment. This change in testing will reduce the diesel particulate matter (DPM) in the exhaust flow, therefore lowering the air quantity required by MSHA. Since Article II-A was based on Part 32 and Part 36 of the Federal Code of Regulations, it will be necessary to make adjustment to the methods for using MSHA ventilation rates to meet the requirements of Article II-A.

In our estimation, the following sections of Article II-A will be affected:

Inby and outby diesel-powered equipment may be used in underground mines if the inby or outby diesel-powered equipment uses an engine approved or certified by MSHA, as applicable, for inby or outby use that, when tested at the maximum fuel-air ratio, does not require an MSHA approval plate ventilation rate exceeding 150 cfm per rated horsepower.

Underground diesel-powered equipment shall include an exhaust emissions control and conditioning system that has been laboratory tested with the diesel engine, except as provided in paragraph (3), using the ISO 8178-1 test, and has resulted in diesel DPM emissions that do not exceed an average concentration of 0.12 mg over M to the third power diluted by 50% of the MSHA approval plate ventilation rate for that diesel engine.

Where multiple units are operated, the minimum quantity shall be at least 100% of the highest approval plate air quantity plus 75% of the next highest quantity plus 50% of the approval plate quantity of each additional unit operating in that split. Air quantity measurements to determine compliance with this requirement shall be made at the most downwind unit of diesel-powered equipment that is being operated in that air split.

Once MSHA Part 7 regulations take effect on November 25, the TAC believes that the following alternative methods as specified below will not reduce or compromise the level of health and safety protection afforded by the Act.

Inby and outby diesel-powered equipment may be used in underground mines if the inby or outby diesel-powered equipment uses an engine approved or certified by MSHA as applicable, for inby or outby use that, when tested at the maximum fuel-air ratio, does not require an MSHA Part 7 approval plate ventilation rate exceeding 75 cfm per rated horsepower.

Underground diesel-powered equipment shall include an exhaust emissions control and conditioning system that has been laboratory tested with the diesel engine, except as provided in paragraph (3), using the ISO 8178-1 test and has resulted in DPM emissions that do not exceed an average concentration of 0.12 mg over M to the third power when diluted by MSHA Part 7 approval plate ventilation rate for that diesel engine.

Section 204-A of the state law is unaffected by the MSHA Part 7 changes. However, since under Part 7, 203-A(1) now requires 100% of the MSHA Part 7 ventilating plate quantities relative to DPM emission levels, the TAC recommends that a minimum of 100% of the MSHA Part 7 approval plate quantity will be required for each unit operating in that split.

Air quantity measurements to determine compliance with this requirement shall be made at the most downwind unit of diesel-powered equipment that is being operated in that air split.

The TAC recommends that, as of November 25, 1999, the Department apply the methods noted above relative to Section 201-A(c), 203-A1, and 204-A(d) of the Act for all previously approved Diesel-Powered Equipment Packages and all future Diesel-Powered Equipment Packages in order to insure that the same level of health and safety protection afforded by the Act remains in place with the implementation of MSHA Part 7 Ventilation Quantity Requirements on November 25, 1999.