2008-04-29_REVISION - C1981019 - Laserfiche WebLink

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31. It was common practice several years ago at the Colowyo Mine to rip, scarify or otherwise roughen the recently replaced topsoil at the mine prior to reseeding. This was often accomplished by using a dozer to rip the topsoil on contour. The main benefit of this practice was to reduce the erosion potential from rain and spring runoff. A secondary benefit is that the pond receiving the runoff the Prospect Pond, in this case) will not receive as much sediment. This practice has been discontinued in the last few years. On site inspections this spring (see in particular the 16 April 2008 inspection report) it was evident that water is flowing uncontrolled over the recently reclaimed surface, causing extensive rilling. This year the snowmelt was pretty gradual and there was still some damage to the reclaimed surface. In years where the snowmelt is faster, the results could be catastrophic. The Division would like to see this practice restarted and requests that Colowyo include a commitment to use surface roughening techniques on all areas where topsoil has been replaced at the Colowyo Mine. This concludes the preliminary adequacy review for the Colowyo Mine Technical Revision 72. The Division would like to have this revision approved and in place so the new reclamation plan can be implemented in this (the 2008) reclamation season. As such, the Division requests your response to the above questions no later than 20 May 2008. Since this response date is also the proposed Decision deadline, the Division requests that Colowyo request a decision extension until 12 June 2008. Please call me at (303) 866-4929 if you have any questions or need any additional information. Sincerely, James R. Stark Environmental Protection Specialist Attachment cc: Sandy Brown Dan Mathews Jon Wangnild, DOW Colowyo Coal Company, C-1981-019 TR-72 April 29, 2008 Page 15