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_pl_ <br />This condition may, in turn, have the effect of causing erosion <br />downstream from the mines to regain the natural level of sediment <br />load. This effect has been suggested on a theoretical basis at <br />several mine sites. However, it has yet to be documented either by <br />the Division's inspectors or by the companies. Should the erosion <br />occur, it would begin immediately downstream from the ponds <br />discharge points. Given the infrequent nature of stream flow in <br />this area, it would not spread rapidly, and could be mitigated if <br />it occurs. <br />Salt Loading <br />Sediment and flow control facilities such as sediment ponds and <br />diversion ditches which detain water will have the effect of <br />increasing the concentration of total dissolved solids in the water <br />due to evaporation. Also, any water pumped from the pits into <br />surface drainages to facilitate operations may contain relatively <br />high levels of dissolved salts. While this is difficult to <br />quantify, the result may be to increase dissolved salt levels in <br />streams draining the mine property. <br />Using data from Williams Draw, the Division has made the following <br />estimate: <br />The average salt discharge of 172.3 grams per day times 62 <br />days gives an assumed annual salt discharge of 10.7 kilograms <br />per year from the Kerr mine plan area within Williams Draw. <br />Considering the respective amount of disturbed area tributary to <br />each of Bolton, Bush, Williams, Sudduth and Mann Draws, the total <br />amount of salt loading on receiving streams is estimated to be <br />about 78.7 kilograms per year. <br />This can be broken down into the amount of loading on each <br />individual stream: <br />Bolton Draw 90.5 kilograms/yr. <br />Bush Draw 3.9 kg/yr <br />Williams Draw 10.7 kg/yr <br />Sudduth Draw 2.7 kg/yr <br />Mann Draw 16.1 kg/yr <br />Canadian River 123.9 kg/yr <br />After reclamation is completed and the sediment ponds are removed, <br />salt loading should drop to natural levels. <br />3. Change in surface water ion balance <br />Data collected by the Kerr Coal Company indicates a change from a <br />calcium-bicarbonate type baseline water to a sodium-bicarbonate and <br />magnesium-sulfate type affected water. These changes, along with <br />the anticipated salt loading, could cause the water quality to be <br />somewhat less suitable for stock water or irrigation. SAR values <br />would be increased. <br />