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It is estimated that Hubbard Creek discharges 24,700 <br />acre-feet per year. Introduction of seven acre-feet <br />per year with a conductivity of 4,900 into a 24,700 <br />acre-feet per year discharge with a conductivity of <br />150 increases the conductivity of Hubbard Creek about <br />1 umhos/cm. This 1 umhos/cm increase is an <br />insignificant impact to Hubbard Creek and the <br />downstream receiving waters. <br />3. Summary and Findings <br />The Division has examined the probable hydrologic consequence <br />due to mining operations for the groundwater and surface water <br />systems at the Blue Ribbon Mine. The Division finds that <br />underground mining at the Blue Ribbon Mine will not have a <br />significant impact on these water systems. The mine will take <br />the necessary measures to ensure that mining will not affect <br />the hydrologic regime (2.01.6(2)(c)). <br />IV. Topsoil <br />A. Little topsoil was salvaged during construction of the mine due to <br />the fact the majority of the disturbance took place before topsoil <br />salvage was a requirement under Colorado law. Previous <br />disturbances to the area associated with the old Blue Ribbon Mine <br />and the highly variable soil depths on the steep slope areas made <br />topsoil salvage impractical. However, topsoil that was salvaged <br />was combined with material from Pond No. 1's embankment and has <br />been shown through soils analysis to be suitable as a plant growth <br />medium. This will result in a respread soil depth of four inches <br />over the entire disturbed area. Suitability of the existing <br />disturbed area soils as plant growth media was limited in two of <br />the six samples taken by a low pH (pH = 5.5). The severity of the <br />limitation is slight and no hazard to reclamation success is <br />expected with the proposed plan. Prior to redistribution, the <br />disturbed area was ripped to eliminate slippage surfaces, relieve <br />compaction, and provide for adequate root penetration. Prior to <br />seeding, the operator sampled all soils and treated with the <br />appropriate amendments as required. <br />V. Sealing of Drilled Holes and Underground Openings <br />A. The alluvial well drilled in the Hubbard Creek alluvium for the <br />mine's water supply has been backfilled and sealed (4.07.3). For a <br />diagram of how the well was sealed, see Plate 17 in the permit <br />application. <br />VI. Use of Explosives <br />A. There are no explosives used at the Blue Ribbon Mine, therefore <br />this section does apply (4.08). <br />_pg_ <br />