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• <br />EXHIBIT 7, ITEM 23, PART C <br />Little Collom Pond (LCX -DS) Design <br />The location of the Little Collom Pond is presented on Exh. 7 -23, Figure Al. Formerly, this <br />structure was referred to as the LCX -DS (Little Collom X Downstream) structure, and the <br />modeling presented in Part A of this section still references that name. <br />This pond will be built before any other mining or construction activities occur. Construction of <br />this pond needs to be concurrent with the construction on the Little Collom Sump pond located <br />upstream. <br />In order to access the construction site and for the routine operation of the pond following <br />construction, an Access road will need to be built connecting the impoundment site to an existing <br />county road. An existing two -track road will be upgraded to accomplish this. See Volume 20, <br />Exhibit 25, Item 1 for the details for this road. <br />The pond will provide ultimate sediment control and the current CDPS discharge permit will be <br />modified to include this outlet. <br />The design drawing for the pond is presented in Exhibit 7, Item 26, Figure 1. Total capacity of the <br />impoundment is about 19.8 acre -feet. Total depth is about 20 feet. This structure is specifically designed <br />• to be a non -MSHA impoundment based on that agency's criteria for measurement of the upstream <br />toe. <br />• <br />This structure will remain in place throughout the life of Collom mine plan and will only be removed <br />concurrent with bond release of the upstream drainage area. <br />The following tables summarize the design details and SEDCAD modeling results as presented in Part A <br />of this section.. <br />Exh. 7 -23C -1 Revision Date: 12/15/10 <br />Revision No.: PR -03 <br />