Controlling Diesel Particulate Matter Exposures in Underground Mines

1. Controlling Diesel Particulate Matter Exposures in Underground Mines William H. Pomroy George P. Saseen Mine Safety and Health Administration pomroy.william@dol.gov 218-720-5448 saseen.george@dol.gov 304-547-2072

2. Available Control Strategies • Ventilation • Environmental Cabs • Administrative Controls • Diesel Engines • Fuels • Maintenance • Biodiesel Fuel • DPM Exhaust Filters Exposure Controls Emission Reduction

3. DIESEL PARTICULATE MATTER EXPOSURE OF U/G MNM Miners Summary of Control Technologies Ventilation, Cabs and Administrative Controls

4. VENTILATION • Widely used method for DPM control • DPM reduction proportional to air flow • Double air flow = 50% DPM reduction • Ventilation can be costly Major upgrades: 16’ dia shaft = $1000/ft Electricity: 250K cfm @ 1” WG = 40 HP 40 HP x 100 hrs/wk @ 10¢/kw-hr = $15K/yr 2x airflow = 8x HP = 8x electricity cost Q: How much air is enough? A: Depends on DPM control strategy

5. How Much Air Is Enough? • PI = Particulate Index = Airflow quantity required to dilute DPM emissions to 1,000 µg/m3 • 2x PI ►500DPMµg/m3 = 400TCµg/m3 = 308ECµg/m3 • PI’s for MSHA Approved engines listed on internet (link to MSHA DPM Single Source Page) • Examples: • Cat 3306 PCTA 215 HP PI = 31,000 cfm • Cat 3176 ATAAC 270 HP PI = 7500 cfm • Boosting air flow a good start, but also need to direct air where needed • Eliminate short circuits and recirculation paths • Ensure coverage in all working areas and faces

6. Series Ventilation - Room-and-Pillar Intake Return Face Line Face Line

7. Dead Ends - Fan and Vent Bag Airflow

8. Dead Ends - Fan and Vent Bag Airflow

9. Dead Ends - Fan and Vent Bag Airflow Auxiliary Ventilation

10. Dead Ends - Fan and Vent Bag Airflow Auxiliary Ventilation

11. Dead Ends - Free Standing Fan Airflow

12. Dead Ends - Free Standing Fan Airflow Auxiliary Ventilation

13. Dead Ends - Free Standing Fan Airflow Auxiliary Ventilation

15. Natural Ventilation • NVP= 0.03”wg per 100 feet per 10oF • For 100’ Shaft and 40o change (15º to 95º) NVP = 0.03 x 100/100 x 40/10 = 0.12” WG • 0.12” WG ► 20K to 50K cfm (typical) • 0.12” WG maximum value - - usually less! • Not sufficient for DPM dilution • Reverses from summer to winter • Very low (sometimes zero) spring and fall

16. Ventilation • Ensure sufficient air volume based on • Equipment emissions – PI’s • Other DPM controls • Natural ventilation insufficient - need fans • Distribute air where needed • Brattice, long pillars, rock/waste filled CX • Need to advance and maintain ventilation controls • May need boosters/auxiliary fans • May need to consult with mine ventilation specialist

17. Environmental Cabs • Environmental Cabs Can: • Reduce DPM exposure and EC levels • Reduce noise exposure • Reduce silica dust exposure • Cabs Should Be: • Tight - seal openings, repair broken windows • Pressurized with filtered breathing air (follow regular filter change-out schedule - 250 hr) • Operated with doors/windows closed (may need air conditioning) • Maintained in good condition

18. Enclosed Cabs

19. Cab Pressurization Monitoring Magnehelic gage with rubber hose extending into cab Magnehelic gage should register + 0.20“ WG or more

20. Cab Pressurization Monitoring • Magnehelic gage should register at least 0.20” WG. If not, check: • Outside air vs. recirculate control setting. Should be set on outside air. • Fan capacity vs. cab volume. Goal should be 1 air change per minute. 100 cubic foot cab requires 100 cfm pressurizer - - 300 cubic foot cab requires 300 cfm pressurizer. • Openings into cab. Close and seal openings. • Air filter. Replace if dirty/clogged. • Intake duct. Remove obstructions, repair and seal holes/damage

21. Environmental Cabs Gap in window seal Cab air filter and pressurizing fan Hoses entering cab

22. Administrative Controls • Control DPM exposures through operating procedures, work practices, etc. • Job rotation prohibited as DPM administrative control [§57.5060(e)] • Job rotation means assigning a job to more than one worker so that each worker does the assigned job for only part of a shift • Job rotation spreads exposure to more workers • In accordance with good industrial hygiene practice, job rotation not acceptable for control of exposure to carcinogens

23. Examples of Work Practices • Work Practices Can Affect Emissions And DPM Concentrations • Minimize engine idling • Avoid lugging engines (low RPM - high load) • Keep fuel and lube oil clean • Traffic control • Route traffic away from areas where miners work outside cabs • Route haul trucks in return air, especially when ascending ramps loaded • Limit HP in work area based on available CFM’s • Schedule blasters on non-production shifts

24. § 57.5067 (a) Engines • Any Diesel Engine Introduced Underground • (a)(1) Have Affixed A Plate Evidencing Approval Under Subpart E of Part 7, Or Under Part 36 • (a)(2) Meet Or Exceed The Applicable PM Emission Requirements Of The U.S. EPA Listed In Table 57.5067-1

25. MSHA Approval No.s • Permissible Engines: 7E-A001 or 07-EPA030001 • Non-permissible Engines 7E-B001 or 07-ENA030001 • Internet Listing of MSHA Approved engines • https://lakegovprod1.msha.gov/ReportView.aspx?ReportCategory=EngineAppNumbers

26. MSHA Approved Diesel Engines

27. EPA DPM LimitsMSHA Table 57.5067-1 • Hp < 11 0.75 g/bhp-hr Tier 1 MY2000 • 11≤ HP<25 0.60 g/bhp-hr Tier 1 MY2000 • 25≤ HP<50 0.60 g/bhp-hr Tier 1 MY1999 • 50 ≤ HP < 100 0.30 g/bhp-hr Tier 2 MY2004 • 100 ≤ HP < 175 0.22 g/bhp-hr Tier 2 MY2003 • 175 ≤ HP < 750 0.40 g/bhp-hr Tier 1 MY1996 • Hp ≥ 750 0.40 g/bhp-hr Tier 1 MY2000

28. Engine Combustion Design • 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 • High Pressure Fuel Direct Injection • Turbocharged • Computerized Electronic Fuel Injection • 0.05 – 0.2 gm/hp-hr for the higher horsepower engines • 2001 - EPA Tier 2 for all horsepowers range from 0.15 g/bhp-hr to 0.60 g/bhp-hr

29. Engine Out Emissions • Total Emissions = Hp specific emissions x Horsepower x Hours of use.

30. Total Engine Out Emissions Emissions x Horsepower x Hours = DPM • Loader: 0.1 x 275 x 8 = 220 grams • Drill: 0.5 x 150 x 4 = 300 grams

31. Three Strikes and It’s Out • Strikes: • High horsepower (greater than 150), • High emissions (greater than 0.3 gm/hp-hr), • High use (greater than 6 hours per shift). • Target Equipment: • Production Loaders and Trucks (primary), • Drills and Scalers (secondary) • PC engines (specialty mining equipment). • One bad engine can spoil the entire fleet.

32. Clean Engines vs. Ventilation • Clean engines reduce emissions by 80 to 90%. • Fuel savings pay for engine in 2 to 3 years. • Estimate that 80% of engines are currently Tier 1 or better. • Ventilation remains important, must be able to remove DPM and other exhaust gases

33. EPA Tier 3 • 50 ≤ HP < 100 Tier 3 MY2008 • 100 ≤ HP < 175 Tier 3 MY2007 • 175 ≤ HP < 750 Tier 3 MY2006 • NOX reductions only, no change in DPM

34. EPA Tier 4 • Hp < 25 Tier 4 MY2008 • 25≤HP<75 Tier 4 MY2008 & 2013 • 75≤HP<175 Tier 4 MY2012 - 2014 • 175≤HP<750 Tier 4 MY2011 - 2014 • Hp ≥ 750 Tier 4 MY2011 - 2015 • Substantial DPM reductions above 25 hp • Substantial NOX reductions above 75 hp

35. Diesel Fuel • MSHA §57.5065 requires diesel fuel with a sulfur content of less than 0.05 percent (500 ppm) • EPA requirement for on-highway diesel fuel to be at 0.0015 percent (15 ppm) sulfur by mid – 2006 • EPA requirement for non-road diesel fuel to be at 0.0015 percent (15 ppm) sulfur by 2010

36. Fuel Additives and Fuel Catalyst • Combustion Enhancers • Cetane booster • Lubricity Increasers • Fuel Catalyst Devices: • Rentar • ECONET - Magnet technology

37. Alternative Fuel Testing • D1 / Jet A / Kerosene – 10 to 20 % reduction • Bio-Diesel Blends – 15 to 50+ % reduction • Water Emulsions – 50 – 75 % reductions • Synthetic Fuels – Synpar 200 and S2 – 30% reductions

38. Synthetic Fuels • MSHA Laboratory Tested 2 Types • SYNPAR 200 – Solvent Based • S-2 – Derived from Methane • Approximate 31% reduction in EC • Associated 4 – 6% loss in horsepower at sea level (1000 feet) • Similar Results at High Altitude, 7500 feet (simulated)

39. PuriNOx™ • A diesel emissions control technology • A means of reducing NOx and PM from diesel engine exhaust • An emulsified diesel fuel (EDF) • Contains up to 20% emulsified water • Stable emulsion • Skim milk in appearance and consistency • When dyed for off-road, looks like “Pepto Bismal”

40. Engine Maintenance • Cleaning: Engine, Radiators, Air/Oil Coolers • Intake Systems: Air Filters, Turbo Boost Pressures, Leaks • Exhaust Systems: Backpressure, Leaks • Cooling Systems • Fuel Systems: Proper Settings, Altitude • Electronic Controlled Systems • Emission Tests

41. Exhaust Leaks • No holes upstream • No loose joints • No evidence of leaks, ie: black streaks on pipes or near exhaust outlets • Check flanges on Catalytic Converters and DPM Filters • Make sure Disposable Filters are Properly Sealed when installed

42. Check backpressure gauge • Backpressure is an indication that the filter is loading up with dpm • Each engine has maximum allowable backpressure specification. Engine specification is listed by engine manufacturer and filter manufacturer • Backpressure is a good indicator for changing or cleaning the filter. • If backpressure exceeds limit, then engine and filter can be damaged.

43. Procedure to determine exhaust backpressure • A Magnehelic gauge is normally used to measure the backpressure. • Install backpressure gauge prior to the filter or other control device. • Run engine at high idle and loaded engine condition • Verify that backpressure is below allowable limit

44. Ceramic Filter Catalytic Converter Engine Total Backpressure BP1 BP measured at BP1 can increase to the maximum allowable backpressure before the filter needs cleaned Deutz BF4M2011 - 30 inches H2O Detroit Diesel OM904LA - 44 inches H2O

45. Gaseous Emission Check • Torque stall the machine to achieve maximum load on the engine • Use a gas analyzer that has a sample probe that can be placed directly in the exhaust gas stream, normally before any control devices • The concentration or changes in concentration of CO above baseline will indicate a change in engine performance. • Some mines are using a doubling of the baseline as an action level.

47. DIESEL PARTICULATE MATTER EXPOSURE OF U/G MNM Miners Summary of Control Technologies Biodiesel

48. Biodiesel - What is it? • EPA registered diesel fuel • Designated alternative fuel per DOT, DOE • 100% biodiesel, neat biodiesel, B100 • Biodiesel blend - biodiesel mixed with petrodiesel, called Bxx where xx is the volume % of biodiesel in the blend • B20 – 20% biodiesel, B2 – 2% biodiesel • Biodiesel is “drop-in” replacement for standard diesel. Any diesel engine will run on biodiesel.

49. Biodiesel – Where does it come from? • (Catalyst) • 100 pounds + 10 pounds 10 pounds + 100 pounds • Triglyceride Alcohol Glycerine Mono-Alkyl Esters • Ingredients: • Triglycerides………..Soy oil, corn oil, canola oil, beef tallow pork lard, used cooking oil • Alcohol………………Methanol, ethanol • Catalyst:………………Sodium hydroxide, potassium hydroxide • Product: • Mono-Alkyl Esters….Biodiesel • Raw Vegetable Oil is NOT Biodiesel ! ! ! • Biodiesel must meet ASTM D 6751-06

50. Biodiesel Properties • High Cetane number • Ultra Low Sulfur (averages ~ 2 ppm) • High Lubricity, even in blends as low as B1 and B2. Can blend with ULS diesel • Reduces emissions of carbon monoxide, carbon dioxide, oxides of sulfur, polycyclic aromatic hydrocarbons, and total hydrocarbons • High flash point • Solvent and cleaning properties