_GENERAL DOCUMENTS - C1981017 (262)

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-35- The .effect of increasing soluble salts is short-termed over the life-of-mine. Upon completion of mining, there will be no discharge from the mines and upon successful rev tion, the preparations plant ponds will be removed. Thus, upon ,n�t n, the soluble salt content of the surf ace water should return t . The mine discharge has not had an effect on the ion balance in the stream. The baseline information indicates that the surface and ground water is dominated by calcium bicarbonate. The mine discharge water and the receiving streams are likewise dominated by calcium bicarbonate. One impacts of the Coal Basin mining activities on surface water is an increase in the sediment load carried in the stream from the road system. Hid-Continent has monitored two streams, Bear Creek and Brad eriick Creek which have drainages that are not affected by the mining ;"Prations. he Division used the average total suspended solids content as the baseline value for determining increased sediment yields from the roads. all the roads are within the Coal Creek an 1, CreekI drainages. ere ore, Iona sediment above the average for Bear (�i n ra ich Creeks was attributed to the roads. Using this method of comparison of the data for Bear and 6raderich Creeks as ambient levels with data for Coal and Dutch Creeks as disturbed samples and the water quality data submitted by the applicant, the Division Jis determined that the road to Kline No. 5 contributes approximately 638 tons of sediment year to Coal '.reek and the Mines 1 , 2, 3, and 4 naul rbads contribute 2.778 tons of sediment per Year to Dutch There are 154 acres of r roads within the permit area, thus, the average sediment yield from the h U9 road system would be approximately 18 tons This figure is ` ` most likely higher than the sedimen actually generated from the roads. b` �y he Bear and 6raderich Creek watersheds are smaller than the Coal and _ r Dutcn Creek watersheds. Likewise, the flows in Coal and Dutch Creeks are higher than in 6raderich and Bear Creeks and sediment loads are greater per unit volume. As flows increase in streams, the velocity also 1 t increases, thus, the capacity of the water to carry sediment is increased. In agricultural areas, an erosion rate of 22'tons/acre/year would be C excessive. However, in steep mountain terrain''wi�th, Urge amount of Nancos shale, this erosion rate is of excessive:, IAe u-- rates In excess of 200 tons per acre are quite common see dater Quality Data in /olume 5) . Therefore, the sediment yield from the loads is not excessive and should not significantly affect water quality. The applicant submitted 3 plan to monitur runoff from t� road system to refine the estimate of sediment generated by the road sys EM. This plan should be adaptable in determining the effects of downgrade a the roads -rom naul roads to access roads upon r_rmpletion of the rock nnel project.