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West Elk Mine <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 />SpriMss <br />Decreed Spring 21 is located within the areas of mining influence of longwall panels LWE5, <br />LWE6, and LWE16 in the NE'/4 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 <br />haulageway and barrier pillar to the haulageway. The overburden depth at this spring site to the <br />E seam is 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 - <br />outside the area of any planned mining influence; 2) a spring located along Dry Fork 700 feet <br />west of the confluence of Poison Creek and Dry Fork, above longwall panel E2 in about 650 feet <br />of overburden to the E seam; 3) Deep Creek Spring over Panel E3; 4) the 96-2-2 Spring over <br />Panel E4; and 5) a spring located south, and outside of the area of influence of longwall panel <br />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), <br />were projected to be impacted by longwall mining. The source of decreed Spring 21 may be a <br />local aquifer in bedrock of the Mesaverde Formation, whereas, the source of the spring along <br />Dry Fork (above longwall panel E2) is likely to be a local aquifer in colluvium or alluvium <br />derived from debris flows. The Deep Creek Spring and the 96-2-2 springs are in colluvium in <br />Deep Creek. <br />f1 ui. et's <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 <br />close when the longwall faces move out of the area of influence of this area. Based on this <br />evaluation, any mining effects on local aquifers can best be identified by monitoring any changes <br />in flow and water levels in springs and ground water. <br />2.05-113 Rev. 06105- PRIG, 03106- PRIG, 05106- PRIG, 111060- TR107, 04107- TR108, 09107- PR12, 02/08- PR12,' 11/10- MR372; 10/20- MR-452; <br />12'20- TR149; 12121- TR150 <br />