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Janet Binns <br />Page 3 <br />April 15, 1999 <br />mg/I to 1600 mg/l. This indicates that this well responded in a relatively short period of time to <br />up gradient mining activities, and is appropriate to identify potential changes in water quality and <br />quantity due to mining at Mine No.3. Average water level and quality for key parameters aze <br />represented below for three periods. <br />W e11008-77-58 <br />Constituent Year <br />1993 (mean) Year <br />1979 (mean) Year <br />1997 (mean) <br />Water elevation (M.S.L.) 6715 6715 6707 <br />Calcium (mg/I) 98 56 118 <br />Sodium (mg/1) 155 189 170 <br />pH 7.75 7.3 7.5 <br />Potassium (mg/1) NA 5 N/A <br />Sulfate (mg/I) 530 439 550 <br />Bicarbonate (mg/I) 483 225 520 <br />Total Dissolved Solids (mg/1) 1029 913 1190 <br />Baseline water can be characterized as sodium-bicarbonate. Coal mining commonly changes the <br />water quality to acalcium-magnesium-sulfate. Review of the data indicates that downgradient <br />water quality has been slightly impacted by mining, likely a result of the migration downgradient <br />of water now resident in the reclaimed pit. This resident water, or spoil water, accumulates in the <br />reclaimed pit area much like water in a bath tub. It subsequently migrates downdip, through the <br />undisturbed rock layers. Spoil water quality at Mine No. 3 is represented by wells 008-SP-4B <br />and 008-SP-SA. <br />Recently, the Division of Minerals and Geology (formerly Mined Land Reclamation Division), <br />as an implementing agency, has been directed to begin protecting existing and potentially <br />beneficial uses of ground water. This authority is granted pursuant to the Colorado Water <br />Quality Control Act and promulgated under the sections 25-8-202, 25-8-203, and 25-8-204. The <br />