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7 <br />1~ Mr. Jim Herron <br />• July 6, 1964 <br />-~ Page two <br />' The quality of ground water in the mine is listed in the table NPDES Discharge Point <br />Water Quality. Because there are not any point sources, the ground water is re- <br />cycled, and ground water is augmented with raw water from Ute Water Conservancy <br />• District, water quality is best sampled at the discharge points. If point sources of <br />ground water are observed in the future, Powderhorn Coal Company shall sample <br />for pH, electrical conductivity, temperature, total dissolved solids, total suspended <br />solids, iron and manganese. <br />The table Ground Water Inflows -Sources denotes water inflows by month. The Ute <br />Water flow was measured and ground water quantity was estimated using the flow <br />rate provided from the table Ground Water Inflows -Locations. The total inflows <br />estimate for ground water assumed no seasonal variation. <br />' Referring to the table Ground Water Inflows -Water Balance, mine inflows are the <br />ground water inflows from known sources and the mine water outflows were cal-_ <br />1 culated from all known sources. <br />• The NPDES Discharge Point Nos. 001 and 002 outflows and the consumption at the <br />preparation plant are measured using flow meters. <br />Moisture leaving the mine via the raw coal circuit was calculated using 2.5 percent <br />1 moisture added by weight per ton of raw coal mined. <br />' Moisture outflows due to the ventilation current were calculated using standard <br />I psychrometric methods. The psychrometrical calculations may have a high margin <br />of error due to the use of average relative daily humidity values. <br />Ground water unaccounted for was calculated to be 4.9 million gallons per year or <br />=~ approximately 9.3 gallons per minute. The quantity may be misleading due to the <br />margin of error found in the psychrometric calculations, specifically average daily <br />relative humidity values which were averaged for the year. Also, seasonal varia- <br />z~ tions in ground water flows may occur which have not yet been observed. <br />If you should have any questions please notify us. <br />1 The continued cooperation of the Division is appreciated. <br />Since ly.„ <br />/ ~ IC <br />Henry A. ~arbe <br />Environmental Specialist <br />~. HAB agn <br />cc: D.L. Fenwick <br />J.E. Stover <br />