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conducted at three labs, the leachate exceeded drinking water <br /> standards in four parameters. One lab reported dissolved iron <br /> concentrations of 6.62 mg/I (secondary drinking water <br /> standards = .3 mg/1); the other labs reported iron at .05 mg/1 <br /> and .06 mg/l. Two labs reported pH's of 8.9 and 9.1 <br /> (secondary drinking water standards = 6.5 - 8.5 pH). <br /> Selenium exceeded standards at two labs which were .04 mg/I <br /> and .025 mg/I (primary drinking water standards = .01 mg/1). <br /> One lab analysis exceeded nitrate levels with 30 mg/l (primary <br /> drinking water standards = 10 mg/1). TDS levels were <br /> 782 mg/l and 720 mg/1 at two labs. The amount of leachate <br /> flow in the underdrains is expected to be low and will be <br /> diluted in the sediment ponds with surface runoff. <br /> The lower refuse pile is expected to have no significant effects <br /> to the surface water system even under worst-case low flow <br /> conditions. The amount of leachate expected to be generated <br /> from the pile is small in relation to the adjacent drainage areas. <br /> The quality of the leachate is predicted to be comparable to <br /> similar waste piles in the North Fork valley with moderately <br /> high TDS, elevated sodium and sulfates, and low <br /> concentrations of metals. <br /> A worst-case discharge projection from the lower refuse pile <br /> has been estimated. Based on an estimated annual infiltration <br /> of 5.7 inches, an annual leachate production of about 19 <br /> acre-feet is predicted from the 40-acre upper refuse site. A <br /> seasonal maximum leaching rate was estimated at twice the <br /> average annual leaching discharging rate of 11.8 gpm. When <br /> added to the leaching rates estimated for the lower refuse pile, <br /> a worst case total seasonal discharge of nearly 50 gpm could <br /> result. <br /> No adverse impact would be anticipated with respect to <br /> arsenic, boron, cadmium, chloride, manganese, nitrate, lead, <br /> selenium and zinc since concentrations of these parameters in <br /> the leaching tests were well below the stream standards on the <br /> North Fork Gunnison River. Furthermore, no adverse impact <br /> would be anticipated with respect to total and dissolved iron, <br /> sulfate, TDS and SAR. <br /> Concerns were raised by the Division regarding surface water <br /> effects of the lower waste pile leachate reaching the North <br /> Fork Gunnison River after the waste pile sediment pond is <br /> removed and the mine site has been permanently reclaimed. In <br /> response, MCC provided an analysis of the worst case effects <br /> to the North Fork of the Gunnison from leachate generated by <br /> the lower waste pile. For the analysis, MCC assumed a <br /> 40 <br />