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Jim McArdle -3- November 30, 1982 Area 10: "Upper Davis Gulch" The applicant has amended its interim plan document to delete proposed regrading of stockpiled materials within Upper Davis Gulch during 1984. Instead, the applicant now proposes to retain the stockpiled materials "in storage in its present location until a decision regarding construction of Davis Gulch dam has been made'-'. In my opinion, this status is acceptable throughout the interim plan time span. However, the applicant should attempt to finalize the decision as rapidly as possible. Upon resolution of this design question, detailed plans and stability analyses should be prepared for the proposed amended configuration of Upper Davis Gulch, including discussion and design of appropriate channel reconstruction and stabilization. Area 17a: "Coarse Ore Stockpile Area" The disturbed slopes within the coarse ore stockpile area may not be stable. However, during the interim plan term, as a permitted area, the site is under the control of the applicant. Control should preclude the exposure of the general public to any hazard due to interim slope instability. Area 18: "Plateau Site" The amended text, additional maps and amended Table D-1 clarify the subareas being delineated within the interim plan. Area 19b: "Plant Access Road, Sta. 153 to 180" The applicant, as discussed above under Section Area 5a, intends to regrade excess fill existing below the roadway at the base of Davis Gulch falls. In keeping with that earlier discussion, I recommend that we require the submission of completed engineered grading plans prior to Apri131, 1983. Further, I recommend that we require the completion of the actual earthwork prior to December 31, 1983. Area 19d: "Plant Access Road, Sta. 280 to 355" Rough grading of the plant access road is complete throughout practically the entire length of the roadway. One obvious exception remains in the vicinity of the common boundary between Areas 9 and 19d. Approximately 1,000 feet of roadway remains incomplete at this point. The resultant high spot compromises the roadway drainage system. In actuality, the existing site condition could allow impoundment of water on the roadway at this point. In addition, the impoundment would eventually overtop, allowing erosive flow downstream from the Coffer dam at the Davis Gulch dam site. In my opinion, the applicant should be required to complete this final segment of the plant access road. It is important for access and maintenance to the plant site that this road remain serviceable under adverse conditions. This failure-prone segment should be corrected in order to improve the serviceability of the existing plant access road.