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The total worse case depletion to the Roaring River Fork River by mine <br /> inflows is small. If all mine inflows were consumed and not discharged <br /> back to the receiving stream, a total of 456 acre-feet/year would be <br /> depleted from the Roaring Fork. This is only 0.06% of the total flow. <br /> Even during the low flow of 179 cfs for the period of record on Roaring <br /> Fork, the total depletion would be 0.4%. This amount is insignificant to <br /> the surface water system. <br /> The impact of all mine discharges on the salt load to the Roaring Fork <br /> River can be calculated assuming a worse case mine discharge and average <br /> salt content. The salt load to the Roaring Fork River from mine <br /> discharges would be increased by 2.2 mg/l. This is 0.8% of the mean <br /> annual salt load normally carried by the Roaring Fork River. Trace <br /> elements and heavy metals are also not found in any high concentrations <br /> which would affect the quality in the Roaring Fork River. Any elevated <br /> levels will be diluted. This should not cause any measurable change in <br /> the water quality of the Roaring Fork River. <br /> Alluvial Valley Floors <br /> The applicant has identified no unconsolidated streamlaid deposits within <br /> and adjacent to the mine site permit area which meet the minimum size <br /> requirement of 50 feet wide and ten acres in extent as set by the OSM <br /> alluvial valley floor guidelines. This was verified by CMLRD through <br /> review of the material submitted and in the field. However, CMLRD <br /> identified an area adjacent to the loadout facility which meets the <br /> geomorphic criteria for an alluvial valley floor. This area is presently <br /> in agricultural use and is irrigated with some indications that portions <br /> are subirrigated. <br /> No part of the loadout facility is physically located on the alluvial <br /> valley floor, thus the proposed operation will not affect the natural, <br /> geologic, and hydrologic characteristics of the alluvial valley floor. In <br /> addition, the loadout facility is not expected to affect the quantity and <br /> quality of surface and ground water that supply the alluvial valley floor. <br /> Soils <br /> The applicant has projected that 12 to 18 inches of topsoil is available <br /> at the new coal refuse disposal area. The applicant's soil survey was not <br /> extensive enough for the Division to determine if proposed salvage depths <br /> are optimal. However, enough data is available to make a finding that <br /> reclamation is feasible. <br /> The applicant projects that 6 to 14 inches of topsoil is available at the <br /> coal refuse pile site and 2 to 24 inches of topsoil is available at the <br /> rock tunnel disposal area. Topsoil is proposed to be replaced to a depth <br /> of 6 to 10 inches on the coal refuse pile and at a depth of 12 to 16 <br /> inches on the rock tunnel disposal pile. A depth of 12 to 16 inches <br /> replaced on the rock tunnel pile should be adequate to obtain successful <br /> revegetation since the majority of the plant roots will be within the <br /> topsoil layer and the rock tunnel waste exhibits no properties which <br /> should limit plant growth. <br /> -14- <br />