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Lower Minnesota Creek Lower East Fork AVF - MCC financially <br />supports the USGS monitoring station on this AVF. This station and <br />MCC's monitoring upstream from the AVF would enable identification <br />material damage to the quantity of water supplying the AVF. Material <br />damage to water quality would not be expected because the mine does <br />not propose to discharge mine water to this drainage. <br />A stipulation regarding the North Fork of the Gunnison AVF was included in the <br />original permit approval requiring MCC to demonstrate that the mining operation's fresh <br />water usage will not materially damage the quantity and quality of water supplying the <br />alluvial valley floor. This stipulation was complied with on March 25, 1982, with the <br />following response: <br />Mining activities at the West Elk Mine will not affect the quantity and quality of water in <br />the North Fork. The coal seam to be mined lies a significant distance above the North <br />Fork and is not considered to be an aquifer. Surface facilities have been designed and <br />located to prevent contamination of the river. <br />Alluvial deposits in Sylvester Gulch and along the North Fork of the Gunnison River <br />next to the mine are too small or irregular in shape to support agricultural activities, and <br />therefore do not qualify as AVFs. High terraces along the North Fork of the Gunnison <br />River are colluvial upland deposits and, therefore, do not qualify as AVFs. <br />Changes in the quantity of water supplied to the North Fork AVF depend on the <br />difference between water used by MCC and water discharged to the North Fork of the <br />Gunnison River. MCC's total water use is expected to be about 150 acre-feet per year <br />during maximum projected production. This represents less than 0.04 percent of the <br />average annual stream flow on the North Fork. Since less than 70 percent of this use is <br />deemed to be consumptive use, the loss is actually less than 0.03 percent of the average <br />stream flow. In addition, water is withdrawn during higher flows when MCC's water <br />rights are in priority. During low flow periods when other calls for water exist, MCC <br />would not be withdrawing water. <br />Water quality changes resulting from MCC's discharge of waste water will not <br />constitute material damage because no measurable change in water quality is expected to <br />occur. Of the 200,000 gallons/day maximum projected use, 38,000 gallons/day <br />(28.5 acre-feet/year) would be required for potable water use. Consumptive use of <br />potable water would be minimal. Assuming no consumptive use, one would expect a <br />discharge of less than 0.06 cubic feet per second (cfs) during plant operation. This use <br />and return flow is insignificant compared to the flows in the North Fork of the <br />Gunnison. Even during the lowest flow on record (17 cfs) for the 1934 through 1979 <br />period of record on the North Fork at Somerset, the potable water use would be less than <br />0.4 percent of the flow. The return water will be treated to meet NPDES effluent limits <br />and should pose no problem for downstream irrigation use of AVFs. <br />53