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Page 6 <br />The accumulated water in backfill spoils resulting from the mining operation was never intended <br />for use as an aquifer, and it is not expected that the backfill water in spoil materials will be put to <br />use in the future. <br />Alluvial Groundwater <br />No direct impact to the alluvial groundwater of Trout Creek was anticipated from mining <br />activities as a portion of strata was left in place between the mine pit and the alluvial valley <br />floor.37 However, the contact between the alluvium and bedrock was much less well defined <br />along the toe of the West Ridge area, and there was an exposed width of an end area estimated at <br />125 feet38 before the longitudinal (pit) barrier at the toe of the slope. All known seeps and springs <br />and all surface water runoff from disturbed areas are directed into permanent sedimentation <br />ponds, and then discharge as surface water across (ditch flow) the alluvial valley floor and into <br />Trout Creek. A stipulation to the permit prohibits the use of discharge from one of the sediment <br />ponds (Outfa11007 of the Colorado Discharge Permit System permit) to irrigate the alluvial <br />valley floor without approval of the Division39 (the discharge can be mixed with irrigation ditch <br />flow drawn upstream from Trout Creek). <br />Water from springs near the toe of the slope from early (pre-law) mining from the West Ridge to <br />near the center portion of the Edna Mine is not suitable (quality) for imgation or drinking.40 The <br />concentration of total dissolved solids (TDS) in Spring C-3 water sample was 2194 mg/l in <br />1979.a~ This spring is near the toe-of-slope/Trout Creek alluvium contact.az <br />The Division concludes that mining activities at Edna may have the potential to impact alluvial <br />groundwater in those portions of Trout Creek valley that are hydrologically down gradient of <br />mining activity.43 Sources of impact include discharges of runoff from surface disturbed azeas <br />and discharges or seepage from within backfilled azeas.aa as a6 Seepage from ditches between <br />surface water impoundments permanent and Trout Creek would be a minimal impact. <br />Any spoil groundwater that reaches Trout Creek would be diluted by the perennial flows of <br />Trout Creek. Trout Creek is a gaining stream (alluvial ground water flow is from the alluvium to <br />the creek). It is unlikely that stream flow in Trout Creek would negatively impact the alluvial <br />groundwater.a~ <br />"PAP page 2.5-97 <br />as PAP page 2.5-95 <br />s9 Permit C-1980-001, Stipulation 38 <br />ao PAP page 2.5-58 <br />a' PAP, Table 2.5-15, page 2.5-59 <br />"Z PAP, Exhibit 2.5-2 <br />43 PAP page 2.5-97 <br />i4 PAP page 2.5-97 <br />as PAP page 2.SA-3 <br />t6 PAP page 2.SA-3 <br />a' PAP page 2.SA-3 <br />