2010-04-08_REVISION - C1981019 (3)

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STATE OF COLORADO DIVISION OF RECLAMATION, MINING AND SAFETY Department of Natural Resources 1313 Sherman St., Room 215 Denver, Colorado 80203 pC O L Ot R N oF Phone: (303) 866-3567 RECLAMATION FAX: (303) 832-8106 MINING Interoffice Memo SAFETY To: Jim Stark Bill Ritter, Jr. Governor James B. Martin From: Kent Gorha Executive Director Loretta E. Pineda CC: Sandy Brown Director Date: April 8, 2010 RE: Completeness Review, PR-03, Colowyo Mine I have completed my review of the additional materials submitted to make the application complete for Permit Revision No. 3 (PR-03) for the Collum Expansion at the Colowyo Mine, #C-81-019. Your latest email concerning my review follows below in italics. I have reviewed the Colowyo PR-03 Incompleteness responses and I have the following comments with regards to the questions I asked you to review (questions 13, 20, 21, 22 and 23). Question 13 - This question deals with a design and geotechnical report for the Little Collom sediment pond. In the initial submittal Colowyo did submit the necessary 10, 25 and 100-year SEDCAD runs but no designs. They have provided the designs in Exhibit 7, Item 25 and the geotechnical report in Exhibit 21, Item 1. This seems to be what we asked for but I would like you to look at what they provided to make sure the information is complete. Additionally, there is very limited text discussing the pond on Collom-Rule 2, Page 96. If we determine that the exhibits they submitted are complete, are we OK with the text portion as well? Question 20 - This question deals with the need to demonstrate effluent limits will be met for stockpiles outside the sediment control structures. Colowyo has inserted a statement that they will cut a "ring ditch" around each pile. This is not really a demonstration. Are we looking for a SEDCAD run that shows the appropriate storm runoff from the stockpile will be contained within the ditch and that any discharge from the ditch (through straw bales or rock check dams) will meet the effluent limits? If so, this is still incomplete and we may need to explain what we are looking for (as I described briefly above) in more detail. Questions 21&23 - These are basically the same question. They deal with the requirement to provide detailed designs and SEDCAD runs for all of the stream channel diversions that will be built to divert water away from the site during mining (like the Little Collom Creek). They have only provided minimal information regarding these diversions in the form of a table. They have not provided designs, profiles or SEDCAD runs for these temporary diversions. This item is still incomplete. Question 22 - This question deals with the permanent, post-mining drainage channels. Colowyo has provided a map showing their locations (Map 41 B), channel profiles (Map 33C) and SEDCAD modeling (Exhibit 7, Item 25). I believe that this item is now complete but I would still like you to review it to make sure that all appropriate SEDCAD runs have been included. My comments follow below for each question. Office of Office of Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines