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<br />-s- <br />the source of the increased T03. ~~ •~aiice tli~~ ground water s}•stem is well <br />defined in the Twenty !file Park ground voter basin based on extensive data <br />collection by EFC, the input parameters of Frieds equations are realistic and <br />the results of the solute transport study is the best available approximation <br />of who[ will happen to ground water quality in the Twenty Mile Park ground <br />water basin af[~r mining has ceased. Even though Frids equation are the <br />present state of [he art method of predicting solute transport some variablity <br />can be expected due to the difficult task of accurately defining the values <br />for longitudinal transverse dispersiuity. Twenty Mile Park Cumulative <br />Hydrologic Effects Map number 53 shows iso-concentratior, lines after 50 years <br />of solute transport. Further the applicant presents a trilinear diagram based <br />on baseline data and the results of the solute model for the four ground voter <br />monitoring wells immediately down gradient of .the mine plan area which <br />demonstrate minimal change in ground water quality. This will no[ affect the <br />use of this water. <br />The 50 year zero iso-concentration line occurs appro:~:imately 5000 to 7000 ft <br />down gradiant from the Eckman Par4: boxcuts. The zero-concentration line is <br />that point where dilution has brought the concentration of solutes in the <br />ground water back to baseline conditions. Based on this information it can be <br />determined that the proposed operations will have a minimum ground water <br />quality impact on the Twenty Mile Park ground water basin. <br />The Northwest Colorado Coal Environmental Impact analysis prepared by B:.M has <br />determined [hat cummulative impacts on ground water as a result of mining <br />would not be significant because grund water use would be minimal, wells and <br />springs would be replaceable if warranted, and added pollutants would not <br />seriously degrade ground water quality for domestic, industrial, or' <br />agricultural use. <br />C. Evaluation of Compliance-Cround Water <br />816.48 Acid-Forming and Toxic-Forming Spoil <br />Chemical analysis of [he overburden and leaching tests performed on the spoil <br />indicate there are no toxic material in the overburden, therefore there is <br />will be no toxic spoil within the mine plan area. The overburden was tested <br />far the following parameters, pH, electrical conductivity, saturation percent, <br />exchangeable sodium percentage, cation exchange capacity, calcium, magnesium, <br />sodium, sodiu, absorption ratio, boron, copper, cadmium, iron, lead, <br />manganese, zinc, nickel, mercury, selenium, molybdenum, ammouianitrate, <br />nitrate ni[raFen, calcium carboua[e, arsenic, potassium, phosphorus, and <br />vanadium. Table 4 shows the statistical discription of [his data. <br />Will Comply <br />816.49 Permanent and Temporary Impoundments <br />Because no_~ermanent impoundments are proposed, no increase in ground water <br />F ~~levels will occur, (v2 pp 816-16). <br />~~~~ ~ <br />