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Elk Creek Mine (C-1981-022) MT- 7 <br />Ground reconnaissance during 1978, 1979 and 1980 identified Elk No. 1 Spring as the only location with <br />ground water surfacing within the original permit area, and this had a flow rate of less than one gallon <br />per minute. It is concluded that there is no large ground water reservoir in the area. <br />Western Slope Carbon identified and monitored 11 springs within or adjacent to the Sanborn East Tract. <br />Monitoring records are available from 1983 through 1987. Somerset Mining Company, now Oxbow <br />Mining, LLC, resumed monitoring these springs in July 1992. Springs 1 through 6 are located along the <br />north boundary of the Sanborn East Tract in the northern portion of Section 2. Springs 7 through 11 are <br />located along the southern boundary of the new tract. The locations of the springs are shown on Map <br />2.04-M5. <br />With Permit Revision No. 5 (PR -05), Oxbow Mining LLC undertook a new survey of surface water <br />resources in the Elk Creek Mine tract. While there are no adjudicated water resources in that tract, the <br />USFS and USBLM requested that OMLLC inventory the resources. Resources identified were added to <br />Map 2.04-M5. <br />The topography of the region is characterized by steep canyons cut by the North Fork of the Gunnison <br />River and its tributaries, with several remnant alluvial terraces above the valley of the North Fork. <br />Proceeding downstream below the town of Somerset the canyon widens. At the town of Paonia, the <br />canyon has given way to a broad alluvial plain with interspersed remnant alluvial terraces. The coal to <br />be mined is located in the Somerset Coal Field. The strata exposed in the Somerset Coal Field consist <br />of the Mancos Shale and the coal -bearing Mesaverde Formation of Upper Cretaceous Age, and of the <br />Ohio Creek Conglomerate, the Wasatch Formation and the Quartz Monzonite Porphyry of Early Tertiary <br />Age. Coal is mined from the Mesaverde Formation, a 2,500 foot thick sequence of sedimentary strata <br />overlain by the Ohio Creek Conglomerate and underlain by the Mancos Shale. The strata in the Elk <br />Creek Mine permit area dip three to five degrees north-northeast within the permit area, but varies <br />locally. <br />The Mesaverde Formation contains a number of coal -bearing members. The Somerset Mine mined coal <br />from the B-2 seam of the lower coal bearing (Bowie) member of the Mesaverde Formation. The Sanborn <br />Creek and Sanborn Creek East additions mined the B and C seams of this member. The Elk Creek mine <br />ramps down to the D -seam mined that level. The Lower Coal member ranges from 260 to 350 feet thick <br />in the Somerset Coal Field and bears three minable coal seams. This member consists of interbedded <br />and lenticular sandstones, siltstones and coals, and is overlain by a massive sandstone, 25 to 225 feet <br />thick which lies directly on the C seam and marks the bottom of the upper coal member. <br />Three categories of potential aquifers exist in the general area: alluvial deposits associated with the <br />North Fork of the Gunnison River and its tributaries, the Rollins Sandstone, and lenticular discontinuous <br />sandstones of the Upper Mesaverde Formation. <br />The largest alluvial aquifers are associated with the North Fork of the Gunnison River. Smaller, more <br />isolated alluvial aquifers are associated with several tributaries of the North Fork. <br />The Rollins Sandstone is the only known sandstone with sufficient porosity and lateral extent to be <br />Page 6 of 14 <br />