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1 , ~ • III IIIIIIIII IIII III 999 COLINA ORO MOLINO, INC. (COM, Inc.) ~YRrdiT 1~ ih s/56 GOLD HILL MILL PERMIT No. M-94-117 JANUARY 25, 1996 REPORT TO THE MINED LAND RECLAMATION BOARD ON MATTERS OTHER THAN TAILINGS POND LINER REPAIR Com, Inc. has accomplished the following items since the last report to the Board on matters other than liner repairs dated December 14, 1995. 1. Water Balance Report COM, Inc.'s consultant, Richard Fox, P.E., completed the survey of the available water storage capacity in the tailings pond and in the Hazel A adit. His report was submitted to the Division on January 9, 1996. This report shows that the tailings pond has remaining capacity, above the tailings and water in the pond up to the low point of the dam crest, sufficient to hold storm water runoff equal to 166% of the 100-year, 24-hour storm event. This assumes that the decant pipes aze closed and that none of the Hazel A storage capacity is used or available. The Hazel A water storage capacity to the top of the bulkhead also was calculated by Mr. Fox. If the Hazel A capacity is available, then the total storage available is equivalent to two back-to-back 100-year, 24-hour storm events. There is reason to question whether the Hazel A capacity will be available during the spring melt, however, due to natural groundwater infiltration. 2. Hazel A Water Infiltration COM, Inc. has now submitted Water Logs to the Division for September 1995 through January 21, 1996, showing the amount of water infiltration into the Hazel A adit which has been pumped up to the tailings pond for storage and evaporation weekly. The data show that the recent infiltration rate during cold weather has dropped to about half the rate last fall. In addition, the data show that the evaporation rate in the pond has been J6Adi~l, /:!J.96