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<br />Cumulative F~ydrologic Impacts of Mining <br />Because of their proximity to each other, the New Etk and Golden Eagle <br />Mines do cumulatively impact the surface and ground water systems in the <br />area. The culmulative hydrologic study (CH IS) prepared as part of the <br />original findings document was restricted to that part of the Purgatoire <br />River Basin above Madrid, Colorado. Such a restriction is practical. <br />Only one other permitted operation lies in the general area. The Raton <br />Creek Mines, operated by Energy Fuels Mining, are located approximately <br />one and one-half miles due south of Trinidad, some 20 miles east of <br />Golden Eagle and New Elk. One additional mine, so far unpermitted, is <br />also a concern. This is the Rimrock Strip Mine which ties approximately <br />one and one-quarter miles northeast of the Raton Creek Mines. The <br />Rimrock Strip Mine qualified for the 9na11 Operator's Assistance Program <br />in early 1988. Filing of a permit application for this operation is <br />anticipated in late 1988 or early 1989. <br />The combined impacts of the Golden Eagle and New Elk Mines include <br />dewatering of the coal seam and overburden aquifers, depleting flow in <br />the stream/alluvial aquifer system, depression of piezometric surface in <br />confined aquifers beneath the coal aquifer, deterioration of the quality <br />of ground water flowing through abandoned coal workings into coal <br />aquifer, and deterioration of water quality in the stream/alluvial <br />system. Due to the separation of Golden Eagle and New Elk Mines from the <br />Raton Creek and proposed Rimrock Strip Mines, no significant cumulative <br />effect is expected on the separate ground water systems that exist in <br />these areas. Since discharges and surface runoff from all of these mines <br />do reach the Purgatoire River, however, there is some potential for <br />cumulative impacts on the quantity and quality of the water in that <br />river. The Raton Creek and Rimrock Strip Mines do not restrict the volume <br />of surface flow to the Purgatoire River through the tributary drainages <br />that these mines adjoin. In fact, discharge from the Raton Creek Mine <br />may increase the volume of flow in Raton Creek. No significant adverse <br />cumulative impact on the quantity of water in the Purgatoire River will <br />then result from the Raton Creek and Rimrock Strip Mines. The TDS of <br />water in Raton Creek are increased by the mining activity at Raton Creek, <br />but, due to the volume of water in the Purgatoire River, any change in <br />TDS values in the River brought about by this increase would be <br />undetectable, It is not anticipated that the small Rimrock Strip Mines, <br />i,e., 20 acres, will appreciably raise the TDS value even in the surface <br />drainages nearby which are tributary to the Purgatoire River. As a <br />result, the impacts of the Raton Creek and Rimrock Strip are cumulatively <br />insignificant as regards the quality of water in the Purgatoire River. <br />The Allen and Maxwell coal seams lie close to one another in the <br />stratigraphic column, separated by approximately 20 feet of interburden <br />material. Disturbance of roof, floor, and interburden material during <br />mining, and subsidence after mining, will result in the breakdown of the <br />interburden strata. Asa result, hydrologic communication is expected to <br />occur between the two coal seams, and ground water impacts are expected <br />to be cumulative. The following assessment considers the two coal seams <br />as one aquifer. <br />-26- <br />