1992-06-24_REVISION - M1988112 (2)

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• Minutes, June 24-25, 1992 :~.. Di~AFT ~. ~ , Subject To Board Approval 5 Mr. Massey asked the Board to consider the information in the record and the fact that the operator has been working diligently to resolve the problem and allow the site to be operated during the interim treatment period. Mr. Roger Flynn, an attorney representing the Peoples Alternative Energy Services of San Luis, and Ms. Nora Jacquez, representing the Costilla County Conservancy District, presented EXHIBIT C, the parties' proposal for short and long term resolution of problems identified with this site. Mr. Flynn discussed the operator's non-compliance with permit requirements, specifically cyanide levels. He requested that the Board issue a cease and desist order and impose the maximum fine against the operator. Mr. Flynn referenced a map from the original permit application and briefly discussed possible negative affects of the operation on surface water flows. Dr. David Hyatt, a consultant representing the Costilla County Conservancy District, addressed the Board and proposed that in order to lower cyanide levels to 4.4 ppm in a short period of time, the addition of cyanide to the system should be ceased. In response to an inquiry from the Board, he said that the total cyanide levels >hould be the basis of analysis, rather than WAD or free. Ms. Jacquez said that during the briefing session provided in relation to the INCO process, they were informed that cyanide levels below 10 ppm were achievable, but that it would be difficult te> reach levels below 5 ppm. She referenced the operator's emergency response plan and proposed that the pond be detoxified by using CyTox and Hydrogen Peroxide, with the administering of cyanide being ceased. In response to a question from the Board, Dr. Hyatt clarified that the objectors would like for the mine to cease the use of cyanide, although the addition of ore to the system could continue. Mr. Flynn and Ms. Jacquez answered questions from the Board. At the Board's request, Staff discussed the potential f~~r groundwater impacts due to seepage through the composite liner of the tailings pond. Staff said the Division concluded that there is approximately 150 feet between the bottom of the pond and the saturated water table, with 30 to 40 feet being unconsolidated alluvium; the remainder is the Santa Fe Formation. Staff said the seepage from the tailings pond will be limited by the composite design of the pond. The Division has calculated that the amount of seepage needed before ground water would be impacted would be in excess of a million cubic feet of water over the life ~f the mine or 8 years. However, the Division calculated that the average amount of seepage for the life of the pond would be about 40,000 cubic feet, and this will not impact ground water, unless the liner is installed improperly.