2019-09-16_REVISION - M1994117 (2)

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CMC Response: CMC commits to monitoring water quality in the Times Mine on a quarterly basis (for the sampling parameters approved in Revision No. AM-01) to evaluate potential concrete degradation of the Times Mine Bulkhead, and to submitting these results to the DRMS in the quarterly groundwater monitoring reports. Once the DRMS has reviewed and approved the new bulkhead evaluation based on the results of the proposed pumping test, which may include different recommendations than those included in the Deere & Ault Consultants evaluation of the Times Mine Bulkhead submitted on May 17, 2019. 6) The operator's response to Item No. 2 states the operation will be limited to processing no more than 5,000 tons of ore at this time (due to limited capacity of the tailings impoundment), and will therefore, require a total of 5,000 tons of water with mill recycling (assuming 1 ton water/1 ton ore) or 20,000 tons of water without mill recycling (assuming 4 tons water/1 ton ore). Please specify how much water will be used in conjunction with the operation in units of volume (gallons), not units of weight (tons), so the Division can easily compare this value to the amount of water the operator is authorized (per Water Court Decree) to withdraw from Left Hand Creek, which is also given in units of volume (3,388,850 gallons during irrigation season). Please be sure the estimated volume in gallons has been properly converted from tons using the appropriate conversion factor, and not a 1 ton water= 1 gallon water conversion, which is incorrect. CMC Response: According to the Denver Equipment Index,one short ton of water equals 239.65 gallons of water. (This is usually rounded up to equal 240.00 gallons of water.) If CMC processes 5,000 tons of ore in the Gold Hill Mill, it will require a total of 5,000 tons of water which equals 1,198,264 gallons of water by recycling the water used in the grinding, classification, and gravity concentration circuits. (Rounded up it equals 1,200,000 gallons of water.) The DRMS can easily compare this value to the amount of water the operator is authorized (per Water Court Decree) to withdraw from Left Hand Creek, which is also given as 10.40 acre feet (One acre feet equals 325,851 gallons of water.) in a dry year, which equals 3,388,854 gallons, and 22.53 acre feet in a wet year, which equals 7,341,432 gallons. The State Water Engineer and the Left Hand Ditch company determine if it is a dry or wet year, and that governs how much water can be withdrawn from Left Hand Creek for processing ore in the Gold Hill Mill. The original, Mined Land Reclamation Board approved Limited Impact Permit for the Gold Hill Mill included the following description of how much water would be used in conjunction with the operation of the gravity and flotation circuits in the milling facility: "This milling complex has been designed to maintain a stable water balance throughout the ore processing and tailings impoundment system. The milling operation will require 4 tons of water for every ton of ore processed in the gravity and flotation concentration circuits. Fresh water will be introduced into the milling process in the grinding circuit. Most of the water that will be used in grinding and classification, and in the gravity concentration circuit, will be recycled from the thickener tank overflow launder back to the ball mill. Fresh water will also be added to the thickened pulp as it passes from the thickener tank underflow to the flotation concentration circuit." The operative word in this description of the Gold Hill Mill's gravity and flotation 5