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Colowyo, C1981 -019, PR3 adequacy No. 3 31 July 22, 2011 <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 />DRMS will complete its review of the proposed hydrologic monitoring plan after receiving the <br />requested changes to ground water monitoring and calculations ofpitwall seepage, spoil <br />saturation, and spoil spring discharges. <br />Rule 4.06 Topsoil <br />L 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)(6)) <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 Stanil <br />A large (250,000,000 cy) temporary ( -20 -year) excess spoil pile is proposed. A Geotechnical Study <br />for the Collom Temporary Spoil Fill, conducted by Shannon & Wilson (S &W), is provided in Exhibit <br />23, Item 1. The fill qualifies as a "Valley Fill ". Map 29C shows plan and cross - sectional views of the <br />proposed pile. General information regarding the pile is provided in Rule 2, pp. 98 -99; Rule 4, pp. 22- <br />23 describes the proposed construction and inspection plans. <br />1. The S &W Study is thorough in its analysis of site conditions, material properties, and analysis <br />of stability. The study is dated July 2009, and was developed using the obsolete plan for <br />mining of Little Collom X Pit. Please update the S &W Study to address any revised ground or <br />spoil pile configurations that may arise as a result of the anticipated changes in mine plan for X <br />Pit. <br />