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-18- A water quality sample from a spoil well at the Wyoming Fuel mine indicates that the spoil water is shifted from a sodium bicarbonate type to a sodium sulfate type. To date, spoil aquifers have not developed in the Kerr and Bourg Mines. Probable Hydrologic Consequences of Mining on Surface Water The Bourg Mine will directly impact 301 acres (0.47 square miles) and will indirectly impact 1,267 acres (1.98 square miles) of Mann Draw. This would result in; 1) directly impacting 14% of the flow in Mann Draw and 0.00014% of the flow in the Canadian River near Brownlee, Colorado; and 2) indirectly impacting the water quality of 0.00099% of the flow in the Canadian River. Under the proposed reclamation plan, 4.23 acre-feet of water will be lost through pond detention. This amounts to 6% of the annual yield in Mann Draw at the mine site and 4% of the total Mann Draw watershed yield. This effect will occur for the life-of mine until the sediment ponds are removed. However, this impact will be alleviated somewhat by an increase in total runoff from the mine. The prediction of increased runoff is consistent with what other mines in this area have predicted (see Kerr Coal application - Marr Strip), but the amount of increase and its duration are not quantifiable. The effects of mining in the Coalmont Formation on water quantity in Mann Draw should not be significant. The applicant states that, although the Coalmont may have some hydraulic connection with the alluvium, most of the recharge to the alluvium occurs through surface runoff recharge. Considering the above, it appears that the operation will have an insignificant impact on the quantity of water in Mann Draw and the effects will be short-terns. Probable Hydrologic Consequences of Mining on Ground Water During mining, the pit of the Bourg Mine may have lowered the ground water levels within the Sudduth coal seam, the overburden, and the underburden. A conservative estimate of the stored water in the Coalmont Formation which was affected by mining is 2 acre-feet (using a specific yield of 10%). The water table map (Plate 1) indicates that lowering the water levels in the Coalmont Formation will not affect the quantity of ground water in the alluvium of Mann Draw, since this formation does not discharge ground water to the alluvium and is not recharged by the alluvium. The Bourg Mine will affect 0.5% of the total recharge area of the Coalmont Formation in the region (160 acres of 40,000 acres total). The quantity of water recharing the Sudduth coal seam is expected to decrease and the ground water quality within this seam is expected to be degraded following mining. Infiltration studies within reclaimed areas of adjacent mines have shown that the infiltration rate will be decreased. This decreased infiltration will reduce the recharge to the spoil aquifer and the strata affected by mining. The ground water quality within the spoil aquifer and disturbed strata will become degraded through the leaching of soluble salts from broken-up overburden materials. There will be an increase in total dissolved solids (TDS) and a shift from a sodium bicarbonate to a sodium sulfate type of