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ditches that will be constructed in the backfill above the West Taylor Fill and a <br />discussion of the terrace ditches that are located on the middle portion of the West <br />Taylor Fill that flow into the West Taylor West Tributary Ditch (from <br />approximately station 25+00 to approximately station 40+00, three ditches). <br />Rule 4.05.6 - Sediment Ponds <br />13. The footer for the West Taylor Pond SEDCAD modeling states that the revision is TR- <br />82. The correct revision number is T R-81. Please change the footer information for <br />the West Taylor Pond SEDCAD modeling to TR-81 to reflect the correct revision <br />number. <br />14. Colowyo provides introductory text :for the South Taylor sediment ponds in Exhibit 7, <br />Item 20 in Volume 13. This introduction is on Pages Exh.7-20-1 through Exh.7-20-7 and <br />contains information regarding soil groups, SEDCAD curve numbers and other <br />assumptions that are used in the SEDCAD modeling of ponds and ditches. This general <br />SEDCAD information was changed and updated as a result of TR-73 for the day-forward <br />modeling at the Colowyo Mine (all ponds and ditches modeled with the pre-TR-73 curve <br />numbers do not need to be remodeled with the TR-73 curve numbers unless changes are <br />made). Colowyo provided new SEDCAD models for the West Taylor Pond and used the <br />new (TR-73) SEDCAD curve numbers. The curve numbers used are correct, based on <br />TR-73, but there is no information regarding these numbers in the introduction. Please <br />add either a separate introduction for Exhibit 7, Item 20, Part C, the West Taylor <br />Pond, that discusses the new curve numbers and SEDCAD assumptions (based on <br />TR-73) or add an addendum or additional introduction to the introduction that is <br />currently in place (Pages Exh.7-20-1 through Exh.7-20-7). Please update the Table <br />of Contents Page Exh.7-20-ii as needed to reflect the changes to the introduction <br />information. <br />15. On Page Exh.7-20-7 Colowyo provides Table 4, which is a summary of the sediment <br />ponds in the South Taylor area. This table has not been updated with the new <br />information from the updated SEDCAD modeling for the West Taylor Pond. Please <br />update Table 4 (Page Exh.7-20-7) for the West Taylor Pond. The subheadings that <br />need to be updated are watershed area, hydrologic parameters and sediment <br />loading parameters. <br />Rule 4.09.2 - Excess Spoil <br />16. In Colowyo's response to the Division's incompleteness question 1 (the Division's 14 <br />September 2009 Incompleteness Letter) a chart is included that shows permanent and <br />temporary fill volumes for the East and West Taylor Fills and the temporary overburden <br />stockpiles. These tables are inaccurate. A reconstruction of the temporary fill volumes <br />(from the 7 December 2009 Colowyo response letter) is shown below.