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r <br />The results of the previous modeling suggest that it could take up to 1,000 years for water <br />to travel from the waste dump to the water table, if it is 400 feet below. Therefore, in <br />addition to the above mentioned well (or in lieu of the above mentioned well if the <br />perched Salt Wash aquifer is found to be dry at that location), Cotter proposes a soil <br />water sampler (lysimeter) be installed. It will be neaz, and on the down-gradient side of <br />the waste rock dump, while still allowing for dump expansion. Approximate locations <br />were discussed with DMG during the field meeting. This wilt serve as a timely sampling <br />system showing the amount and quality of water percolating through the dump material. <br />2) To address the impact of underground mining operations on the perched groundwater: <br />Cotter is not presently impacting the perched groundwater quality since water entering <br />the mine is pumped, treated, and discharged. It is Cotter's contention that the perched <br />water is limited in aerial extent, has extremely low flow rates due to limited recharge, low <br />permeability, and lacks hydraulic forces due to a flat dip, and is of poor quality. To test <br />the validity of these arguments, Cotter proposes sampling of the groundwater entering the <br />mine, the well mentioned above, and azea seeps and springs. This information will <br />characterize the groundwater quality and, in conjunction with age dating and possible <br />flow measurements in the well to detennine the rate and direction of groundwater <br />movement, will be useful in evaluating the possible impact to the perched water once <br />pumping ceases. <br />The Division's determination (Third Review from Harry Posey and Kate Pickford to <br />Russ Means, March 6, 2006) that the JD-9 Mine is a DMO because "re-flooding of <br />underground workings with perched aquifer water from the Salt Wash formation would <br />have the potential to violate state-wide standards" is "based on SPLP results". Cotter <br />does not believe that the acid solution used in the SPLP test represents the leaching <br />potential of the groundwater in the mine. Therefore, Cotter proposes doing bottle roll <br />tests on materials representative of rock exposed in the underground workings using Salt <br />Wash groundwater. <br />Cotter estimates that it will take about 120 days for drilling and construction of lysimeter <br />and monitor wells, sample collection, bottle roll testing, sample analyses, evaluation of <br />results, and report preparation. <br />If you have further questions regarding these issues, please call Glen Williams, Manager, <br />or Dick White at Cotter's Nucla office, 970-864-7347. <br />Re~~ly <br />Dick White, Project Geologist <br />Cotter Corporation <br />