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.S. <br />Conclusions and Recommendations <br />Existing water resources within the leasehold and immediate vicinity <br />that will be affected by mining are subsurface waters contained in the <br />r; <br />j' target coal seam, the Laramie formation overburden, and the blow sand <br />i and stream deposits associated with a broad flat depression known as <br />~ Ennis Draw, The Larimie-Foxhills formation, the most important aquifer <br />in the area, is more than 200 ft below the coal seam proposed to be mined. <br />No effects of mining on the Laramie-Foxhills aquifer are anticipated. <br />Surface runoff in the area is essentially non-existent under present <br />conditions. This is not expected to change provided that three or more <br />feet of the existing blow sand are placed over the spoil in the reclam- <br />ation phase. <br />The target coal seam and the Laramie overburden are hydraulically <br />independent aquifers. The coal seam is a confined aquifer but waters in <br />the overburden are only locally confined. Flow of ground water through <br />the coal seam is negligible as the transmissivity of this aquifer is <br />extremely small. Groundwater flow in the overburden is toward the north- <br />east. Approximately 5.4 acre-ft of groundwater per year are discharged <br />from the leasehold area. This flow apparently enters the blow sand and <br />stream deposits associated with Ennis Draw. The source of this flow is <br />external to the study area and enters the project area by lateral flaw. <br />Recharge of the overburden aquifer in the study area is believed to be <br />essentially zero. <br />The water in the overburden aquifer is of poor quality, the dissolved <br />. solids concentration exceeding 7000 mg(1 with a sodium-adsorption-ratio <br />greater than 10. Probably the only viable use of the water in the over- <br />burden is for dust control or similar purpose. Waters contained in the <br />