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RULE 2 PERMITS <br />Chemical equilibrium calculations indicate that alkaline precipitations can maintain low <br />concentrations of Al, Cd, Cu, Fe, Pb, and Zn. <br />The report further concluded that application of chemical equilibrium equations to the generally alkaline <br />characteristics of western streams and aquifers implies that this precipitation equilibrium limits soluble <br />heavy metal concentrations in groundwater. <br />The work by Skogerboe can, in part, explain why heavy metal concentrations in groundwaters near or <br />adjacent to coal mining operations in northwest Colorado have not been a serious problem. Most of the <br />waters in the area are alkaline which, according to Skogerboe, limits or reduces the solubility of heavy <br />metals in surface and groundwater. <br />Because of this phenomenon, heavy metal concentrations in surface and groundwaters near or on the <br />Colowyo mine permit area are not expected to be significantly affected. <br />Samples of drainage water, i.e., leachate, were collected and analyzed by VTN (1975) to show <br />concentrations of water quality constituents of concern as a result of mining in northwestern Colorado. <br />Table 2.04.7-6 presents this information. It is interesting to note that these values are not significantly <br />higher than the values from the other wells sampled or from the surface water samples. Turbidities <br />(JTU's) are negligible, which is to be expected of water seeping through a large filter. Iron is low with a <br />value less than 1.0 mg/1. The major ions are within the range of the other samples analyzed. <br />Table 2.04.7-6 is representative of concentrations from water subject to natural percolation, leaching, and <br />contact with the floor materials of the Streeter Mine. Water entering the Streeter Mine came from surface <br />runoff and traveled through cracks and fissures in the fractured rock above the mine. It is likely water <br />traveled and leached through the strata in this manner for a long time prior to mining in the Streeter Mine. <br />Table 2.04.7-6 should be viewed as concentrations that can be expected to develop over time as leaching <br />continues through the Colowyo spoils and concentrations of minerals available to leaching decrease. <br />Considering the physical condition and mineralogy of the spoils, the predicted effects of the spoil would <br />be a gradual increase in TDS and associated major ions for a period of time, followed by a general and <br />gradual decrease in concentration back to ranges seen in background data and Table 2.04.7-6. <br />Rule 2 Permits 2.04.7-7 Revision Date: 6/23/08 <br />Revision No.: MR-91