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Section 8 <br />Groundwater Quality <br />• Groundwater use is also limited in a wider area surrounding the Sunday Mines <br />Group based on a search of the Colorado Division of Water and Natural Resources <br />well permit database. Several wells are currently permitted in an area near the <br />Dolores River southwest of the Sunday Mines Group. These wells are listed in Exhibit <br />8-1 along with aliquot part legal descriptions of the well locations and the <br />approximate distance of the wells from the Sunday Mines Group. <br />The closest well to the Sunday Mines Group is a BLM stock well reported to be in the <br />Dakota aquifer. The well is located south of the Sunday Mines Group in the central <br />portion of Disappointment Valley. The Dakota aquifer is located stratigraphically <br />above the Salt Wash aquifer, which contains the underground mine workings. These <br />two aquifers are separated by a confining layer composed of bentonic shale of the <br />Brushy Basin member. Therefore, it is unlikely that water from the underground mine <br />areas would communicate with the Dakota Aquifer in this area. The development <br />rock area of the West Sunday mine overlies the Dakota aquifer in the Big Gypsum <br />Valley area on Figure 8-2. However, the Dakota aquifer in the Big Gypsum Valley <br />area is a fault bound block of Brushy Basin Formation and Dakota Sandstone, which <br />is not contiguous with the Dakota Aquifer in Disappointment Valley. The other wells <br />in the general area of the Sunday Mines Group are located at extensive distances (i.e. <br />greater than four miles) and/or are upgradient from the mine areas. Information <br />regarding the depth of the wells is not available. <br />• <br />Exhibit 8-1. Wells Located in General Vicinit of Sunda Mines Group <br />Well Location Permitted Distance from Comments <br /> Uses Sunday Mines <br /> Group <br />SE '/4 SW '/4 Sec. 25, Stock 2.4 miles Well is potentially downgradient from <br />T44N, R18W, NMPM1 mine workings. However, the well is <br /> located in the Dakota aquifer, which <br /> overlies Salt Wash Aquifer and is <br /> isolated from Sunday Group Mine <br /> workings by Brushy Basin Confining <br /> Unit. <br />NE % SW % Sec. 25, Industrial, Approximately 5 Located southwest of mine area, <br />T44N, R19W, NMPM Domestic miles gradient to mine area unknown. <br />NE 1/4 SE % Sec. 31, Domestic, Approximately 4 Located southwest of mine area, <br />T44N, R18W, NMPM Stock miles gradient to mine area unknown. <br />NW % NW % Sec. 33, Domestic Approximately 4 Located northeast of mine area, <br />T45N, R18W, NMPM miles u radient from mine areas. <br />Notes: 1 New Mexico Principal Meridian <br />Potential future uses of groundwater in the area of the Sunday Mines Group are <br />limited by the land ownership and the BLM Management Plan for the area. The <br />affected areas of the Sunday Mines Group are included within Management Area 3 <br />(MA 3): Natural Landscape with Limited Management. Management activities for areas <br />with this designation are defined as follows (BLM 2008): <br />Management activities are allowed, but limited, on MA 3s. They occur mostly <br />for restoration purposes needed because of natural disturbance events or past <br />• management actions. Management activities may include restoration of <br />ecological conditions or habitat components; prescribed burns, wildland fire <br />8-6 <br />TA64988-Denison MinesVTask Order 4- EPP Sunday Mines GroupTINAL EPPTINAL - Environmental Protection Plan Sunday Mines.doc