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Appendix 15 — Groundwater Well Details <br />Groundwater Monitoring Well Installations <br />As part of the Environmental Protection Plan for the Revenue Mine, three wells were designated for <br />installation to monitor water seeping from the Revenue and Atlas tailings and waste rock piles. These <br />wells are shown on all mine maps of the approved permit. Well 1 was located to monitor water from the <br />Atlas pile and Wells 2 and 3 were designated to monitor the water from the Revenue Pile. In April of <br />2014, excavation began to install these 3 wells to bedrock and it was found that the ground conditions <br />at the well locations were different than previously thought. A simplified cross section of the three <br />locations is provided on the attached Map G -14. <br />Map C -4 shows cross sections of the three well locations with respect to the full tailings /waste piles. <br />As can be seen from the cross sections of map G -14, 2 distinct layers of ground water were identified <br />from the excavations. The upper groundwater zone is apparently located above a layer of old fine <br />tailings which are dark in color and has considerable clay. At the well locations, this layer was never <br />excavated during the mine construction and waste rock placement in the late 1800's. The clay in this <br />layer is blocking the movement of groundwater below this point. The extent of this layer is unknown <br />throughout the actual footprint of both tailings piles. The excavation below this original tailings layer <br />revealed that the round stones and fine mud from ancient flooding of the Creek in this lower layer was <br />also permeable to the extent that water was flowing into the pit from Sneffels Creek as the material was <br />excavated. This layer, as shown on the cross sections, is below the Creek level. Bedrock was never <br />attained in Well locations 2 and 3 while it was encountered at a depth of 16 feet in Well 1. <br />In order to ensure that we are not missing any seepage water from the tailings /waste rock piles at any <br />well location, it has been decided to install 2 wells at each sample location. One will be at the original <br />Revenue Mine TR -04 Appendix 15 Page 1 <br />