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West Elk Mine <br />~~ There aze 15 springs that have been located in or near the permit revision azea, as shown on Map <br />37. Only low flow observations have been made at these springs. Of these, four springs are <br />considered perennial (10-1, 15-1, 15-2 and 24-3). The maximum observed flow rates have all been <br />less than 10 gpm to date. Identified ephemeral springs E13-2, E13-3, E13-4 and perennial springs <br />E13-1 and 24-3 (Map 37) aze outside the azea to be affected by subsidence in the West Flat Iron <br />Lease. MCC plans to add springs 10-1, 24-3 and E14-1 to the monitoring program as described in <br />Section 2.04.7. The range of flow data aze presented in Table ;43, Exhibit 57, and in annual <br />hydrology reports. <br />Most springs in the lease block derive their water from perched aquifers in the colluvium and <br />Barren Member of the Mesaverde Formation. The fact that mostisprings dry out during the late <br />summer indicates that the groundwater reservoirs supplying the springs aze limited in extent. The <br />discharge rates of the springs respond closely to precipitation events, another indication that the <br />rechazge areas for the springs are very localized. <br />There aze three different types of springs within the permit area: <br />1. Alluvial Springs -Subsurface water moving through the alluvium emerges as a spring, and <br />discharges into the drainage channel. <br />2. Colluvial Springs - Colluvial groundwater moving downgradient emerges from the <br />(, colluvium as a spring. The source of the groundwater in the colluvium can be snowmelt <br />infiltration, rainfall infiltration, dischazge from a surface channel or upgradient bedrock <br />spring flows that infiltrate into the colluvium. <br />3. Bedrock Springs -Springs can be encountered where subsurface formations outcrop. <br />Groundwater moves along the surface of the formation and eventually daylights. <br />Aicmrir ring iLlnnimring Warn -Spring monitoring to establishibaseline data and to assess the <br />impacts of mining in the F-Seam has been conducted by MCC for over 10 yeazs. Monitoring of <br />springs potentially subject to impact from B-Seam mining has been conducted since 1992. The <br />relevant data indicate that F and B-Seam mining has had little, if any, impact on spring flows. <br />Specific information on spring-related mining impacts for these seams can be found in the Annual <br />Hydrology Reports from 1982 to the present. <br />Plots of spring flow hydrographs aze contained in the Annual Hydrology Reports. Considerable <br />variation from yeaz to year is also apparent along with the seasonal pattern. A comparison of <br />operational data with pre-mining data reveals no discernable difference. Flow monitoring will be <br />continued by MCC in order to assess trends over time. A visual comparison of the data presented <br />in the Annual Hydrology Reports reveals a lack of correlation among spring flows. <br />MCC has been building a representative database for springs in the permit and lease azeas, since <br />1978. Sufficient baseline data, in accordance with CDMG regulations have been established to <br />(, enable future determinations as to whether longwall mining could be affecting the springs. As <br />1.05-157 November 2004 PRI / <br />