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It could be possible for water to discharge from the portals once the mine <br />workings have become completely flooded. The portals are up-dip in the mine <br />and drainage will tend to move down the dip of the mine and coal seam, thereby <br />increasing the time to flood the workings; however, it is uncertain if the <br />drainage out of the mine area through the coal seam will exceed the drainage <br />into the mine from overlying strata. If outflow does not exceed inflow, some <br />discharge from the portals may occur. The applicant has proposed backfilling <br />of the portals and construction of concrete bulkheads upon closure of the mine, <br />minimizing the possiblity for discharge of water. <br />The development and reclamation of the cuts and fills in the portal areas <br />should have no impact on the bedrock aquifer system. Recharge of the aquifers <br />does not occur in these areas, so possible degradation of infiltrating waters <br />in the more permeable fill will not reach these aquifers. The fill material <br />itself is generally of suitable quality as a topsoil substitute except for SAR <br />values which are up to twice as high as defined in the Wyoming Guidelines for <br />suitability. As water flows through the fill, total dissolved solids may in- <br />crease due to solvable salts; however, this occurs naturally within the exist- <br />ing ground water region. The fill does not contain materials which create a <br />toxic leachate. Water which infiltrates the fill may reach Scullion Gulch, <br />however, due to the small area of disturbance relative to the entire drainage <br />basin for Scullion Gulch, this will be a very minor contribution of flow in. the <br />creek. See the Surface Water Section for further details. <br />The applicant provided additional information on May 29, 1981, to substantiate <br />the non-toxic and non-acidic nature of the spoil material, refuse material, and <br />roof and floor rock in the mine. This information will be incorporated into <br />the application. See the proposed stipulation. <br />The applicant will be obtaining part of the required water supply from wells in <br />the White River alluvium. Approximately 600 gpm will be pumped from the <br />aquifer to a head tank in the D-Portal Area. This is less than one percent of <br />the low flow of the White River. Therefore impacts will not be significant. <br />5 <br />