2015-01-29_REPORT - C1981018 - Laserfiche WebLink

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During the 1996 -1997 period, Deserado Mine started disposing the prep plant thickener water in the mined out area of the D -Seam (the first longwall district). This water would have been otherwise discharged through Pond PP -2. Ingoing Water The production equipment utilizes water for dust control and cuttings removal in roof bolting. Water used by equipment is based on 314 shifts worked by continuous miner sections and 327 shifts worked by the longwall. The continuous miner sections use 100 gpm and operate about 4 hours per shift (the rest of the time is spent moving, etc.). The longwall equipment uses 200 gpm of water for about 8 hours per shift. The amount of water entering the mine as ventilation intake air humidity is based on monthly mean temperatures from Table II.0 -1 on page II.0 -5 of the Mining Permit and the yearly mean relative humidity of 56% found on page II.E -1 of the Mining Permit. The absolute humidity, the actual amount of water in the air, is calculated from these data using an average ventilation quantity of 421,308 cubic feet per minute. TABLE 2 -2 MINE WATER BALANCE WATER IN GALLONSNR GALLONS /MIN Production Equipment 38,928,000 74.06 Ventilation Humidity 8,963,847 17.05 Underground Storage of Thickener Water 3,200,000 6.09 Incidental (pipe leaks, road watering, wash down) 3,892,800 7.41 TOTAL 54,984,647 104.61 WATER OUT Coal Surface Moisture 19,840,067 37.75 Ventilation Humidity 18,694,849 35.57 Pumped Out 13,631,834 25.94 TOTAL 52,166,750 99.25 Water Left Underground 2,817,897 5.36 Water pumped from B seam to D seam 0 0 Thickener water transferred underground for storage was estimated at 3,200,000 gallons during the reporting period. This number is based on operational knowledge of the tons washed and other factors such as the type of clays encountered, processing equipment efficiencies, etc. E