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Attachment A, Technical Revision to the May Day Mine Permit, September 12, 2009. 3 of 19 <br />David B. Kirkpatrick, Esq. <br />1/30/2007 <br />Page 2 of 5 <br />The water after the processing will be conveyed to a lined settling pond. <br />The amount of water needed in the processing is between 35 and 40 gpm of <br />which 75% is recycled from the settling pond and 25% is fresh water. The <br />theoretical maximum amount of annual water use will be about 4.6 acre-feet (AF) <br />based on 10 hours per day and 250 days per year. Water for processing will be <br />obtained from the discharge from the Idaho and/or Mayday mine portals. This <br />discharge presently flows to the La Plata River which is less than 1000 feet west <br />of the mines. <br />The out of priority depletions will be augmented by storing water in lined <br />ponds when the water rights (Case No. 06CW91) are in priority then released <br />according to a schedule determined by the Division Engineer. The storage <br />ponds will be filled by diverting discharge water from the Idaho and/or Mayday <br />mine portals. In summary, the proposed SWSP is to allow storage of water when <br />in priority to release to the La Plata River to augment out of priority depletions. <br />The amount of out-of-priority depletion is based on the water needed in <br />the mining process. An estimated 3 tons of water is needed to process 1 ton of <br />ore and the maximum amount of water needed per hour is 10 tons which is 2400 <br />gallons or 40 gpm. The range of water use is between 35 and 40 gpm of water <br />of which about 75% (27 - 30 gpm) is recycled from the Settling Pond and about <br />25% (8 - 10 gpm) is fresh water. The processing is expected to operate a <br />maximum of 10 hours per day for 250 days per year- If the maximum processing <br />occurs, the annual depletion will be between 3.7 acre-feet if 8 gpm to 4.6 AF if 10 <br />gpm, Based upon an historical call record analysis, on an average year, the <br />annual out-of-priority depletion will be 1.85 AF, but would be about 2.5 AF in a <br />very dry year. <br />There are also ponds to be used in the ore processing and for <br />augmentation. The settling pond will be about 1 AF. Once filled initially, there <br />will be evaporation from the pond which will be replaced by 8 to 10 gpm diverted <br />for processing. This 8 to 10 gpm will not be totally consumed in the ore <br />processing and is expected to be more than adequate to replace evaporation to <br />keep the pond full during the longest call period. One augmentation pond will be <br />constructed initially. The primary pond will be Pond #1 and be about 31 AF in <br />capacity and a possible second pond will have up to 2.5 AF of capacity. These <br />ponds will be filled whenever water is in priority which could be 3 to 4 times per <br />year. The ponds will not be continuously filled unless in priority to do so. The <br />amount of water available for augmentation is after evaporation from the ponds <br />and if there is less than the required augmentation volume then diversions for ore <br />processing will cease.