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West Elk Mine <br /> <br />2.05-113 Rev. 06/05- PR10, 03/06- PR10, 05/06- PR10, 11/060- TR107, 04/07- TR108, 09/07- PR12, 02/08- PR12; 11/10- MR372; 10/20- MR-452; <br /> 12/20- TR149; 12/21- TR150, 1/24-TR152, 2/25-MR486 <br />Springs, Aquifers, and Ground Water Wells <br />Map 37 and Exhibits 71 and 71A provide information on the springs located within the mining areas. <br />Most springs likely have sources from local aquifers in surficial material (debris flows, colluvium, <br />and possibly alluvium). <br />In contrast to surface water containment structures, such as reservoirs, ponds, streams and <br />ditches, springs and aquifers may have water sources that are either in bedrock beneath the <br />blanket of clay-rich surficial material (debris flows, alluvium, and colluvium), or have a source <br />from within the surficial material. Subsidence may affect a spring or aquifer source located in <br />bedrock, whereas effects may or may not be expected where the spring source is within the <br />surficial material. Tension cracks produced in sandstone bedrock during the subsidence process, <br />for example, may divert water to a lower rock layer and therefore change the flow location. <br />However, local aquifers in permeable zones, which are interlayered with clay-rich zones <br />(Wasatch clays) in the surficial deposit, may yield to tensile stresses without cracking. There is <br />no field documentation known to Mr. Dunrud to either support or refute this statement. Annual <br />Hydrology Reports submitted to the CDRMS each year provide monitoring data and note <br />potential impacts from mining. <br />Springs <br />Decreed Spring 21 is located within the areas of mining influence of longwall panels LWE5, <br />LWE6, and LWE16 in the NE¼ of Section 5, (Township 14 South, Range 90 West). Maximum <br />tilt and strain is expected to occur in this area, because it is located above the projected haulageway <br />and barrier pillar to the haulageway. The overburden depth at this spring site to the E seam is <br />about 650 feet. <br />Springs mapped in the South of Divide mining area, which have been found flowing at every site <br />visit, include: 1) a spring located 800 feet west, southwest of the Minnesota Reservoir dam -outside <br />the area of any planned mining influence; 2) a spring located along Dry Fork 700 feet west of the <br />confluence of Poison Creek and Dry Fork, above longwall panel E2 in about 650 feet of <br />overburden to the E seam; 3) Deep Creek Spring over Panel E3; 4) the 96-2-2 Spring over Panel <br />E4; and 5) a spring located south, and outside of the area of influence of longwall panel E8. <br />Of the springs mapped, Deep Creek Spring over Panel E3, the 96-2-2 Spring over Panel E4, the <br />decreed Spring 21, and the spring located along Dry Fork and above longwall panel E2 (J-7), were <br />projected to be impacted by longwall mining. The source of decreed Spring 21 may be a local <br />aquifer in bedrock of the Mesaverde Formation, whereas, the source of the spring along Dry Fork <br />(above longwall panel E2) is likely to be a local aquifer in colluvium or alluvium derived from <br />debris flows. The Deep Creek Spring and the 96-2-2 springs are in colluvium in Deep Creek. <br />Aquifers <br />Horizontal strain produced during subsidence could impact local water-bearing bedrock beneath <br />the blanket of clay-rich surficial material. It also may impact local aquifers in surficial material, <br />where permeable and saturated zones are stratigraphically positioned in zones of tensile strain. <br />Impacts may occur for long periods of time where the aquifer is located above mined boundaries <br />and barrier pillars - areas where permanent strain occurs. On the other hand, dynamic strains and <br />related cracks produced by subsidence above moving longwall faces in a given area are nil and