Published on December 5, 2007
Controlling Diesel Particulate Exposures in Underground Mines : Controlling Diesel Particulate Exposures in Underground Mines Robert Haney Chief, Dust Division Jeff Moninger Mechanical Testing Division Provisions as Published in the Federal Register on Jan 2001: Provisions as Published in the Federal Register on Jan 2001 § 57.5060 Limit on the concentration of DPM* § 57.5061 Compliance determinations § 57.5062 DPM control plan* § 57.5065 Fueling practices § 57.5066 Maintenance standards § 57.5067 Engines § 57.5070 Miner training § 57.5071 Environmental monitoring § 57.5075 Diesel particulate records *Proposed changes DPM Sampling Train: DPM Sampling Train SKC Submicron Impactor (Double Quartz-Fiber, Filter) Cyclone Breast Plate Pump Concentration Calculations: Concentration Calculations TC = OC + EC TC = 1.3 x EC OC* or EC* = 1000 x g/cm2 x Area 1.7 x 480 Area = 8.04 sq. cm. *Corrected for control MSHA Baseline Compliance Assistance Sampling Results: MSHA Baseline Compliance Assistance Sampling Results 172 Mines Sampled Specific mine results on web site 48 Mines over 400 ug/m3 124 Mines below 400 ug/m3 49 Mines below 160 ug/m3 Average concentration - 218 ug/m3 Average max. concentration - 338 ug/m3 Available Controls: Available Controls Ventilation Clean Engines Environmental Cabs Work Practices Alternative Fuels After-Filters Ventilation: Ventilation Particulate Index – amount of air required to dilute whole emissions to 1000 μg/m3. Double this airflow would dilute whole particulate to 500 μg/m3, which is the same as 400 μg/m3 TC or 308 μg/m3 EC. For approved engines see MSHA website. Ventilation Rates: Ventilation Rates Successful mines had mine airflow greater than the sum of the PI’s for all operating equipment (150,000 to 250,000 cfm). Mechanical ventilation is needed. Intake should not be next to exhaust. Natural ventilation is not reliable for these airflows rates due to low pressure developed and seasonal changes. Distribution Systems: Distribution Systems All methods need distribution system: Long blocks Brattice lines Auxiliary fans and tubing Inlet needs to be in fresh air Clean Engines: Clean Engines Pre 1993 Direct Injection Engines 0.5 – 1.0 gm/hp-hr. Indirect Injection (Pre Chamber) Engines 0.3 – 0.5 gm/hp-hr. Post 1993 Direct Injection Engines 0.05 – 0.2 gm/hp-hr. Replace PC and Old DI engines with New DI engines Environmental Cabs: Environmental Cabs Environmental Cabs Can Reduce DPM Exposure Reduce Noise Exposure Reduce Silica Dust Exposure Cabs Should Be: Pressurized With Filtered Breathing Air Operated With Doors/Windows Closed (May Need Air Conditioning) Maintained In Good Condition Work Practices: Work Practices Keep powder crews upwind of production loader and trucks. Provide separate air course for powder crew. Schedule powder crews on different shift than production loader and trucks. Operate haulage vehicles (with environmental cabs) in exhaust air courses. Alternative Fuels: Alternative Fuels Bio-diesel Blends Water Emulsion Fuel Additives Fuel Catalysts Alternative Fuels: Alternative Fuels Graph After-Filters: After-Filters Passive regenerated ceramic filters, Self regenerate based on duty cycle. Active regenerated ceramic filters, Need regeneration station. High temperature “paper” filter, Filter life based on duty cycle and operating time. Fuel burner with ceramic filter Creates temperature as in passive type system DPM Exposure Estimator: DPM Exposure Estimator Conduct simulation to assist in developing control strategy. Need to measure exposures. Need to assess engines and use. Need to determine air flows. Conclusions: Conclusions Ventilation – mechanical ventilation and distribution system is needed. Total mine airflow should be > the sum of equipment PI’s. Clean Engines – a must. Replace PC and old DI engines with new DI engines. Environmental Cabs – maintain seals blower and filtration system. Conclusions: Conclusions Work Practices – Apply particularly to blasting crews. Work upwind or on different shift from production equipment. Alternative Fuels – 10 to 50 % reduction. Must weigh cost vs. benefit. After-Filters – Selection is based on temperature profile. Not needed for interim limit. Most likely will be needed to meet the final limit.