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Rule 4.09.2 - Excess Spoil <br />7. With the submittal of Technical Revision 81, Colowyo is proposing to revise <br />the volume and configuration of the East Taylor Fill. The currently approved <br />capacity for the fill is 50 million cubic yards. Colowyo proposes to decrease the <br />capacity of the East Taylor Fill to 20.3 million cubic yards. This decrease in volume <br />will result in a change to the configuration of the permanent fill. Colowyo has not <br />provided any designs (besides the new Map 45), engineering reports or geotechnical <br />stability analyses for the proposed fill volume and configuration. Please provide the <br />Division with designs, engineering reports and geotechnical stability analyses <br />for the proposed volume and configuration of the East Taylor Fill. <br />Response: We believe that the design of the temporary and permanent fills is <br />accurately described in plan view and cross-sections associated with Map 45. <br />Included with this submittal is the geotechnical stability report prepared by Shannon <br />& Wilson, Inc. for the fills. This has been formatted as "Exhibit 21, Item 1, Third <br />Introductory Letter" with this submittal. This report revises the original spoil pile <br />design that was approved for South Taylor under PR-02. This report addresses the <br />stability of all spoil stockpiles included with this plan. In general, the report <br />addresses the stability of the total stockpile, including the upper portion which is the <br />temporary portion. This constitutes the worst case condition and demonstrates long <br />term stability for the flatter, permanent spoil pile slopes. <br />In this report, Figure 1 illustrates proposed changes to spoil pile slopes that were <br />recommended to achieve the desired factor of safety for stability of the various <br />slopes. These relatively minor changes have been implemented with the revisions <br />to Map 45 included with this submittal. <br />8. Colowyo is still proposing to temporarily stockpile spoil material on the East <br />Taylor Fill. The original design called for stockpiling approximately 30 million cubic <br />yards of material on the pile (in stockpiles TS West 1, approximately 10.5 million <br />cubic yards and TS West 2, approximately 19 million cubic yards). Based on <br />approved map 35A - Bond Calculation Map Worst Case Topography, the entire <br />surface of the East Taylor Fill would have been used for the temporary stockpiling of <br />spoil. Colowyo has not provided any information on the amount of temporary spoil <br />that will be stockpiled on the East Taylor Fill under the revised plan. In addition, <br />based on the newly made Map 45 - South Taylor Fill, the configuration of the <br />temporary spoil stockpile has changed. Colowyo has not provided any construction <br />plans, engineering reports or stability analyses to demonstrate that the East Taylor <br />Fill will remain stable, in its redesigned configuration, with the proposed temporary <br />spoil stockpiled on it. Please provide the Division with detailed information <br />regarding the amount of material that will be temporarily stockpiled on the <br />East Taylor Fill, construction plans for the temporary stockpile and <br />engineering reports and stability analyses that confirm that both the East <br />Taylor Fill and the temporary spoil stockpiles will remain stable during the <br />construction and reclamation phases of mining. In addition, please update the <br />text regarding this temporary overburden stockpile in Section 2.05.3(6) of <br />Volume 12 and Maps 35A and 40A.