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(III IIIIIIIIIIIIIIII` 999 STATE OF COLORADO DIVISION OF MINERALS AND GEOLOGY Department of Natural Resources 1313 Sherman St.. Room 215 Denver, CO 80207 Phone: 17031 866.3567 f AX: 1303) 832-8106 Date: February 15, 1994 To: David Berry, Dan Hernandez, Harry Ranney From: Kent Gorha ~ Re: Chimney Rock Mine, Permit No. C-81-023 Partial Phase II Bond Release Request of cow ti~ 4 .r~~" M ~~ Roy Romer Governor M,chael 8. long Div~sron Duecvn I have completed my review of the above-mentioned Phase II Bond Release request. My comments are as follows: General Discussion Inspection of aerial photos and discussion with Harry Ranney helped to portray the current drainage control system that exists on the bond release parcels. Long contour ditches were immediately recognized on the Barren Ridge area and the East Pit. Signs of instability (gullies, ditch breaches, etc.) were evident, and this was apparently due to excessive rainfall in the recent past. Vegetative cover appeared to be average and in many cases appeared much better than many of the steep, barren slopes in the surrounding area. I also inspected a photo of the approved reference area, which was covered with rock and sparse vegetation. Another photo revealed a massive load of sediment recently delivered to one of the ponds. Based on this general overview, I then proceeded to review the permit text for the approved reclamation practices to determine conformance with the present on-the-ground configuration. A number of inconsistencies were revealed. First, both Division personnel and the operator seem to have a basic misunderstanding on what constitutes a contour furrow. In the manual Design of Sediment Control Measures for Small Areas in Surface Coal Mining (Simons, Li, and Associates, May 1983), contour furrows are described on page 5.2. "Contour furrows are generally spaced 5 feet apart, are 20 to 30 inches wide and 8 inches deep and should be dammed at intervals of 4 to 9 feet." This is dramatically different from the flowing contour ditches which currently exist at Chimney Rock. Simons, Li, and Associates go on to say, "This treatment is considered to be a highly successful mechanical treatment for establishing vegetation." It would seem logical to me to use techniques to retain moisture on the Chimney Rock reclamation rather than rapidly divert this moisture from the reclaim. Vegetation is the key to long-term stability and any and all techniques should be used to optimize the vegetative cover.