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2 <br />blow sand and stream deposits associated with Ennis Draw exhibit a much <br />better quality, the dissolved solids concentration ranging between 750 <br />and 1000 mg/1. There is, apparently, subsurface flow from the south in <br />Ennis Draw which is sufficient to•dilute the small quantities of saline <br />inflow from the Laramie, <br />The quantities of pit inflow were estimated using a succession-of- <br />steady-states computation procedure, together with the mining plan and <br />the hydraulic properties of the aquifer as determined by aquifer tests <br />on the proposed mining site. The peak inflow rate is estimated to be <br />some 130 gpm and will occur when pit B has reached its maximum length <br />of 3000 ft. The inflow from both pits A and Bare. included in this <br />estimate. The estimated peak inflow is believed to represent a maximum <br />that can reasonably be expected to occur. Several aspects of the com- <br />putation tend to cause the estimates to error on the high side. The <br />quality of the inflow should not be substantially different from the <br />quality of existing overburden waters. The distance from the pit to <br />points where the piezometric surface in the overburden will remain undis- <br />turbed is approximately 0.5 miles. Therefore, at any time, drawdown of <br />the piezometric surface in the overburden is not expected to extend more <br />than about 0.5 miles beyond the boundaries of the area to be mined. <br />~~~ Unless specifically avoided, the pit will apparently intersect and <br />~q • ~ <br />~ `~~ cut through the stream deposits and blow sand associated with Ennis Draw <br />j in one limited area. Inflow to the pit from these deposits may equal or <br />exceed the inflow .from the Laramie. Drawdown of the piezometric surface <br />in these deposits caused by mine inflow can be expected to be substantial <br />It is recommended that special care be taken to protect the integrity <br />of the ground waters in the blow sand and stream deposits associated with <br />i <br /> <br />