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.; The Pittsburg & Midway Coal Mining Co. A Chevron Company Edna Mine P.O. Box 176, Oak Creek, CO 80467 (303)736-8111 Re: West Ridge Hydrologic Plan Progress Report III IIIIIIIIIIIII III p~S 13199 M~NERP~S 8 Ms. Susan Morrison October 7, 1992 CMLRD 1313 Sherman St. Room 215 Denver, CO 80203-2273 Dear Ms. Morrison: This letter will serve as a progress report on the Edna Mine's West Ridge Hydrologic Plan. This progress report partially satisfies requirements set forth in Stipulation #31 of the Edna Mine Permit (C-80-001) for yearly reporting, by October 31 of each year, until project completion. The mine received it's first significant snowfall of the year on October 6, therefore this report notes progress to that point. It is doubtful that additional work on this project will be done during this year due to weather and scheduling constraints. Work began on the project in June of this year following final approval of the plan from the CMLRD. As noted in the schedule, (Appendix 4.6-M of the Permit) the first phase of the project involved construction of the lower portion of Terrace #6 (Refer to Exhibit 4.6-M3 of Permit for terrace numbers and locations). Terrace 6 was built from it's lowest point in the draw between Center Ridge and West Ridge to a point near the existing West Ridge haul road. Corrective measures were then made in the drainage patterns from the West Ridge haul road to allow drainage to flow to this terrace (Refer to documentation on N.O.V. #C-90- 041). Following completion of this first phase of the project work on Phase 2 began with construction of the check dams in the draw between Center Ridge and West Ridge. These dams were to be constructed starting at the southern end of the draw and proceeding down the draw. To date, 11 of the 23 check dams have been constructed, starting with the two Type 1 dams above the haul road, then one Type 2, three Type 3, four Type 4 and one of the Type 5 dams (Figure 4.6-M1 and Table 4.6-M1 list design criteria for the check dams) below the haul road. To gain access to the draw in a manner that would disturb as little reclaimed ground as possible the lower sections of Terraces 7B, 8B and 9B were constructed. These partial terraces were used for roadways to haul rip-rap material to the constructed check dams. All of the existing structures have been checked and meet the minimum design criteria set forth in the Permit document.