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2.04.7-12 and 13 in the Permit and Table 1). pH varies from 7.2 to 8.4. The USGS report <br />indicates that concentrations of trace metals rarely exceed health limits. Specific conductivity <br />averages approximately 1400 mmhos with a range between 720 and 2700 mmhos, exceeding <br />USEPA secondary drinking water standards (see permit pages 2.04.7-14 through 18 and Table <br />2). The above factors, coupled with low selenium levels ranging from 0.001 to 0.002, allow the <br />water to be used for stock watering. <br />A USEPA report entitled 'Environmental Effects of Western Coal Mining, Part IIP' suggested <br />that the alkaline nature of western water (including that within this permit area) may limit or <br />reduce the solubility of heavy metals concentration in waters near or adjacent to a coal mining <br />operation. This fact, together with a low coal sulfur content (0.33 to 0.57 percent), more than <br />likely accounts for the low trace metals found in the somewhat alkaline groundwater on the <br />permit site. <br />In conclusion, impacts of the Colowyo surface mining operations on bedrock aquifers are <br />confined to the permit area and are not expected to be significant. The potential for the Collom <br />pit to negatively impact alluvial groundwater in Little Collom Gulch, and to a lesser extent <br />Collom Gulch and the West Fork of Jubb Creek is acknowledged and is addressed by the <br />establishment of a groundwater point of compliance in each of the three drainages. <br />A slight potential for degradation of alluvial groundwater was recognized in the Permit and the <br />1982 Findings Document. A plan was approved to monitor alluvial ground water on Goodspring <br />and Wilson Creek. Results of monitoring indicate no detectable impacts on alluvial ground water <br />to date. <br />Pursuant to Rule 2.07.6(2)(c), the assessment of the probable consequences of the proposed <br />mining operation and the assessment of the probable cumulative impact of all anticipated mining <br />in the area on the hydrologic balance, as described in Rule 2.05.6(3), have been made. The <br />proposed operation has been found to be designed to prevent material damage to the hydrologic <br />balance outside the permit area. <br />Based on the review of the groundwater at the Colowyo Mine, stipulation No. 7 was added to the <br />permit with the approval of PR -02, and remains in effect: <br />PR -04, Colowyo Coal Mine C1981-019 44 August 2016 <br />