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f III IIIIIIIIIIIIIIII <br />999 <br />Addendum to the Findings, <br />Basin Resources, New Elk Mine, C-81-012 <br />July 28, 1995 <br />The following is an addendum to the findings of compliance for the New Elk Mine. This <br />document was last published during the permit renewal on January 21, 1995. <br />On December 30, 1993, Basin Resources submitted a revision to the New Elk mine <br />permit to allow for the disposal of coal fines underground. The coal fines are generated <br />at the coal preparation plant. The fines will be pumped as a slurry to the East Portal and <br />then to other areas of the New Elk mine workings as the mains fill. The slurry will be <br />comprised of 34 percent solids and pumped at a maximum rate of 700 gpm. The slurry <br />will flow down dip and the coal fines will gradually settle out. The transport water will <br />be pumped out of an existing borehole at a rate of 462 gallons per minute and recycled <br />to the preparation plant. The coal fines are expelled to fill 70 percent of the mains upon <br />the completion of the operation. <br />Basin Resources has estimated that the life of the slurry operation will be 5 years at the <br />proposed deposition rate. After the operation is completed, the mine will eventually <br />flood with mine inflows. The borehole that was used to draw off the decant slurry water <br />will be monitored and will later be sealed. The borehole is located north and adjacent <br />to the alluvium of the Purgatoire River. Samples of preparation plant water, that likely <br />represent the quality of slurry decant water, exceed receiving stream standards for nitrate, <br />ammonia, and cadmium. Slurry water will be diluted with inflow water flowing from <br />up<lip locations. Mine inflows from down-dip locations and under the river will pass <br />through the settled fines and will likely have the water quality of the slurry decant water. <br />This water is not expected to be discharged to the Purgatoire River. The statement of <br />probable hydrologic consequences for this mine begins on page 2.05-58 of the permit <br />application. <br />In the unlikely event that discharge does occur, it will most likely be from the East <br />Portal, located 42 feet in elevation above the river. Other drillholes and mine openings <br />lower in elevation than the East Portal will be sealed. In the past, mine inflows have <br />been measured underground at a rate of 120 gallons per minute. Mine inflows are <br />expected to decrease as the workings flood and the cone of depression flattens out. <br />From monitoring of the coal seam water level at other locations, Basin estimates that <br />water levels in the mine will recover to an elevation of 10 feet below the East Portal. <br />If the mine were to discharge from the East Portal at the current rate of mine inflow, the <br />discharge would be greatly diluted by the relatively large flow of the river to well below <br />-1- <br />