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RULE 2 PERMITS <br /> Creek. Through a carefully documented and conducted program of sampling,the report concluded <br /> that: <br /> • The impact of mine spoil drainage on the surface water is reflected by larger <br /> quantities of dissolved solids and common ions. <br /> • The mine has no detectable impact on surface water in terms of increasing <br /> concentrations of Al, As, Cd, Cr, Cu, Fe, Pb, or Zn. <br /> • Increases in stream concentrations of Mn and Se due to mine inflow can be inferred. <br /> • Higher concentrations of As, Fe, Mn, Se, and Zn are found in water draining mine <br /> spoils. <br /> • The concentration of these elements varies with spoil age. Mn and Zn are higher <br /> in older spoils and As, Fe, and Se are higher in newer spoils. <br /> • Chemical equilibrium calculations indicate that alkaline precipitations can maintain <br /> low concentrations of Al, Cd, Cu, Fe, Pb, and Zn. <br /> The report further concluded that application of chemical equilibrium equations to the generally <br /> alkaline characteristics of western streams and aquifers implies that this precipitation equilibrium <br /> limits soluble heavy metal concentrations in groundwater. <br /> The work by Skogerboe can,in part,explain why heavy metal concentrations in groundwaters near <br /> or adjacent to coal mining operations in northwest Colorado have not been a serious problem. <br /> Most of the waters in the area are alkaline which, according to Skogerboe, limits or reduces the <br /> solubility of heavy metals in surface and groundwater. <br /> Because of this phenomenon, heavy metal concentrations in surface and groundwaters near or on <br /> the 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 <br /> Colorado. Table 2.04.7-6 presents this information. It is interesting to note that these values are <br /> not significantly higher than the values from the other wells sampled or from the surface water <br /> samples. Turbidities (JTU's) are negligible, which is to be expected of water seeping through a <br /> large filter. Iron is low with a value less than 1.0 mg/1. The major ions are within the range of the <br /> other samples analyzed. <br /> Table 2.04.7-6 is representative of concentrations from water subject to natural percolation, <br /> leaching, and contact with the floor materials of the Streeter Mine. Water entering the Streeter <br /> Mine came from surface runoff and traveled through cracks and fissures in the fractured rock above <br /> the mine. It is likely water traveled and leached through the strata in this manner for a long time <br /> prior to mining in the Streeter Mine. Table 2.04.7-6 should be viewed as concentrations that can <br /> be expected to develop over time as leaching continues through the Colowyo spoils and <br /> Rule 2 Permits 2.04-18 Revision Date: 12/20/19 <br /> Revision No.: TR-135 <br />