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Colowyo, C1981-019, PR3 adequacy No. 2 23 April 22, 2011 <br />which could negatively impact the quality of alluvial ground water in Collum Gulch. The <br />leachate can be expected to have TDS concentrations greater than 3,000 mg/l, compared to <br />native alluvial ground water TDS generally less than 2,000 mg/1. <br />5. DRMS does not propose establishing a ground water point of compliance for bedrock <br />hydrostratigraphic units. DRMS is considering the need for a bedrock ground water monitoring <br />well or wells that would not be established as points of compliance. DRMS will complete its <br />review of the proposed hydrologic monitoring plan after receiving the requested calculations of <br />pitwall seepage and spoil spring discharges. <br />6. Colowyo has created a new water monitoring plan for Collom, independent of the existing <br />monitoring plan. However, in the past, the plan for a new area (South Taylor) was included in <br />the original monitoring plan. Left unchanged, the Colowyo permit will have two separate <br />water monitoring plans for the three distinct areas. Please include Collom water monitoring in <br />a single water monitoring plan for the entire permit area. <br />Rule 4.06 Topsoil <br />1. In the Topsoil handling section of the application, Rule 4, page 20, CCC makes the statement, <br />"Topsoil stockpiles will not be moved when required for redistribution on disturbed areas prior <br />to seeding." The Division is unsure what CCC is trying to say with this statement. Please <br />review this section of the application and revise accordingly. (Rule 4.06.3(2)(b)) <br />CCC reworded this section of the Topsoil redistribution section. CCC's response is acceptable. <br />2. In the discussion of Topsoil redistribution, Rule 4, page 20-21, CCC commits to variable <br />topsoil depth replacement but does not explain how this will be implemented. A discussion of <br />the variable topsoil depth replacement is found in Section 2.05.4(2)(d). Topsoil handling map <br />28C does not show which topsoil thickness will be placed on the regraded contours. Please <br />provide the Division additional information regarding variable topsoil depth replacement on the <br />regraded landscape. A map with the post-mining contours showing the range of topsoil <br />replacement depths within a defined area would be appropriate. This replacement depth range <br />could be associated with slope gradient, post-mining land use, aspect, or other factors. <br />Proposed replacement depth needs to be. described prior to placement and not only reported <br />after it has been placed as proposed in application Section 2.05.4(2)(d). <br />CCC updated Map 28C to show the requested information. This item has been adequately <br />resolved. <br />Rule 4.09 Disposal of Excess Spoil <br />The Division is currently reviewing CCC's March 28, 2011 submittal for response to the Division <br />concerns regarding the excess spoil pile and associated issues. The Division will forward any <br />outstanding concerns on this topic under separate cover.