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Mr. Michael Cunningham 4 CDRMS December 13, 2013 The other 2 down - gradient wells (DW07, and DW08) are about 0.3 and 0.5 miles from the Mill and are located on the South side of California Gulch. 4. Currently there is only one ground water monitoring well at the mill. The well (MW -1) is approximately 20 feet deep and is completed in unconsolidated glacial outwash. The Operator has only collected one ground water sample from MW -1 since 2009. As noted above, the Division has identified two domestic wells which are on the adjacent properties to the west of the mill. These two wells are completed in the same unconsolidated glacial outwash and range in depth from 75 to 100 feet deep. Currently MW -1 serves as the compliance point for the mill site. Since MW -1 is not of sufficient depth to reach the aquifer which the two nearby domestic wells are completed in, it is not reasonable to assume that sampling MW -1 will capture potential impacts to this aquifer. Therefore, the Division will require the applicant to deepen or replace MW -1 to a depth which will allow for consistent sampling of the alluvial aquifer. Please respond. The Division has determined that in addition to MW -i at least one more well will be required to adequately capture the down gradient ground water flow which could potentially impact the adjacent domestic wells. The Division will require the Operator to install a second well on the west side of the TSF. The well should be located as close as possible to the western permit boundary and should be completed in the alluvial aquifer. Please respond. Response: UMC concurs that a monitoring well of sufficient depth to reach the aquifer (85ft -100ft depth) is required and commits to its installation prior to commencing operation. However, given the small size of the TSF (about 400ft in length along the Southern embankment) we believe that only one deep monitoring well is required. Additional monitoring wells will, however be required during future expansions of the TSF. UMC proposes the following: MW -1 (approximate coordinates N39 °13'45 ", W106 °19'56 ") as it currently exists will remain active. A new monitoring well MW -2, drilled to a depth of 85ft -100ft will be placed down - gradient of the TSF near the Southwest corner of the property boundary (approximate coordinates N39 °13'44 ", W106020'00'). UMC obtained a permit application from the State Engineer and will submit this application upon approval by the Division. In addition, UMS proposes an up- gradient well, MW -3. There is an existing non - permitted well on the property (presumed coordinates N39 013'50 ", W106 °19'58.75 "). This well was discovered and reported to the State Engineer by UMC shortly after we had purchased the property. We spoke with a past employee of Leadville Mining and Milling and he indicated that the well was located somewhere near the Northeast corner of the mill building. UMC has, so far been unable to locate this well. The well is cased and is operational, pumping water to the raw water tanks located on the north end of the mill building. An up- gradient monitoring well will also sere to supplement historic regional EPA ground water data and presented to the Division as the 5- quarter baseline data in our Amendment application.