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Air Ptmdt Applitmion jor [ormcuo Cad Ca~mry <br />Emission Factor and Controls • <br />The emission factor for vehicles is: <br />k*5.9*(s/12)*(S/30)*(W/3)"0.7*(w/4)'0.5 !b/vehicle mile <br />(AP~2, Section 11.2.1, dated 9/88) <br />where: <br />k =particle size multiplier (dimensionless) = 0.36 for PM~o <br />s =silt content of road surface material under gravel (~) = 27% (Lorencito Canyon Mine Permit <br />Application submitted to Division of Minerals and Geology, Colorado Depat~tent of Narural <br />Resources, Denver, Colorado, December, 1996) <br />S =mean vehicle speed (mph) =see below for each vehicle type <br />W =mean vehicle weight (tons) =see below for each vehicle type <br />w =number of wheels =see below for each vehicle type <br />Control of fugitive dust is accomplished by gravel on the roads and water the roads "'as needed' • <br />on days when precipitation does not occur. These controls achieve a 50 percent emissions <br />reduction for gravel roads, and a 25 percent emissions reduction for watering "as needed". <br />Annual Emissions <br />Water Trucks <br />A Mack DM-800 water truck with a capacity of 10,000 gallons will be used to water the haul <br />roads. Watering of haul roads will be done every one of the 255 work days when precipitation <br />does not occur. For the annual emission factor, the "precipitation days" factor ((365-p)l365) <br />where p =number of days with at least 0.01 inches precip = 65 or 17.8%a of the time is included. <br />An assumption is that the need for watering on days without precipitation will be similar over the <br />working days. Therefore, the precipitation emissions reduction factor (0.8219) for the 255 <br />working days will be the same as for the entire year. Therefore, watering will be required on 210 <br />days (255 days * 0.8219). The mileage driven on each watering day is assumed to be 25 miles. <br />The average weight of the watering truck is 54 tons, and the average speed is 10 mph. The water <br />truck has six wheels. Therefore, annual uncontrolled emissions will be: <br />14.54 Ib/vehicle mile * 210 days * ZS miles/day = 76,335 Ibs/yr = 38.17 tons/yr <br />A Caterpillar 763 water truck will be used on the surface mine four hours per day. Similar to the • <br />haul rozd water truck, it is assumed that the surface mine water truck will be needed 210 days per <br />.~..,,ev,~~.rv io. iw~ 27 <br />