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III IIIIIIIIIIIIIIII STATE OF COLOiv-~uv DIVISION OF MINERALS AND GEOLOGY Dcpanmem of Natural Resources 131 J Sherman $L, Ruum ? 15 Dcnvcr. Colorado dU_'03 Phone: UU31 fl66-356: FAY' IJUJ) b3J-til Ufi DATE: August 14, 1997 TO: Mike Boulav FROM: Susan Burgmaier~ RE: West Elk Mine (C-80-007) Minor Revision No. 220 Materials Storage Bench Expansion II~~~ DEPARTMENT OF NATURAL RESOURCES Roy Romer Governor lames 5. Lochhead fsecmive Dveaar Michael B. Long Dinsion Director I have reviewed MCC's response to my adequacy concerns. Following aze my comments which should be forwazded to the operator. 2. The Division agrees with and will approve the additional information provided for ditch D2-6C and culvert C2-3A. The design information provided for ditch DCW-2 and watershed 21, however, appear to be in error. The SEDCAD run provided is based on a watershed area of 1.8 acres with a curve number of 72. The previous run in Exhibit 66 was based on an area of 5.87 acres, which is consistent with what DMG gets digitizing the area. The curve number should be 79, since additional area will be disturbed. The map transmitted to the Division on July 11, 1997 (copy enclosed) shows a fill area which is roughly half the acreage of watershed 21. DMG digitized these areas, and found the disturbed area to be 2.8 acres, and the undisturbed 3.l acres. A weighted average curve number, using 88 for disturbed areas and 70 for undisturbed areas, is 78.54, which rounds up to 79. Please revise the design for ditch DCW-2 accordingly. MCC needs to address the requirements of Sections 4.05, 4.06, 4.09, and 4.15. Specifically, MCC needs to specify the final location of the excess 3,000 CY of excess spoil material, and demonstrate that the material will be stable; the fill will minimize disturbance to the prevailing hydrologic balance; topsoil in the proposed location will be salvaged, stored and replaced as required; and disturbed areas will be revegetated appropriately. In addition, MCC needs to demonstrate that the designated fill area can be returned to approximate original contour with the addition of the excess spoil. 6. The topsoil stockpile locations and volumes are now cleaz to DMG. We did note, however, that there remain apparent errors or shortcomings in the information provided. a. Topsoil stockpile #4, listed on Table 36A, is not on the referenced Map 53B. b. Topsoil stockpile #6, shown on Map 53B, is not listed on Table 36A. c. A number of stockpiles, including the pile on the MSB, is not labeled on the map, and is therefore difficult to identify. Thus, our confusion. While these issues have no bearing on the approval of MR 220, it would be helpful if MCC could correct these problems.