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West Elk Mine <br />SprinQS/Seeps <br />This section addresses PHCs for the springs and seeps in the current, South of Divide and West <br />Flatiron perrnit revision areas. <br />Freguency of Occurrence and Nature ofSprinps <br />The range of flow data is presented in Exhibit 57 and in Annual Hydrology Reports. <br />There aze over 90 springs in the current permit area, as shown on Map 37. More than 90 <br />percent of these have at least 270 feet of overburden above the highest seam to be mined. Four <br />springs in the current permit area exhibit significant flows: Spring G-26A (peak flow during spring <br />runoff up to 75 gpm) in Lone Pine Gulch; G-24 (up to 120 gpm) in Sylvester Gulch, and G-25 (up <br />to 90 gpm); G-31 (up to 45 gpm) in Gribble Gulch; and D-2, J-4 and J-10 (up to 30 gpm) all in the <br />Apache Rocks permit revision area. There are 15 springs that have been located in or near the Box <br />Canyon permit revision areas, as shown on Map 37. Only low flow observations have been made at <br />these springs. Of these, four springs are considered perennial (10-1, 15-1, 15-2 and 24-3). The <br />maximum observed flow rates have all been less than 10 gpm to date. <br />Identified ephemeral springs E13-2, E13-3, E13-4 and perennial springs E13-1 and 24-3 (Map 37) <br />are outside the area to be affected by subsidence in the West Flatiron Lease. MCC Plans to add <br />springs 10-1, 24-3 and E14-1 to the monitoring program as described in Section 2.04.7. The range <br />of flow data are presented in Table 43, Exhibit 57, and in annual hydrology reports. <br />• Fifty springs/seeps have been identified in the South of Divide permit area. Most of the <br />springs/seeps have negligible yield. Only four of the springs have been identified as perennial <br />(WCC-24, J-7, J-2, and 35-3), of which only J-7 is within the area of mining influence. <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 most springs dry out during the late <br />summer indicates that the groundwater reservoirs supplying the springs are limited in extent. The <br />dischazge rates of the springs respond closely to precipitation events, another indication that the <br />rechazge areas for the springs are very localized. <br />There are 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. Coluuvial Springs - Colluvial groundwater moving downgradient emerges from the colluvium as <br />a spring. The source of the groundwater in the colluvium can be snowmelt infiltration, rainfall <br />infiltration, discharge from a surface channel or upgradient bedrock spring flows that infiltrate <br />into the coliuvium. <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 />• <br />2.05-/95 Revised June 2005 PRIG, January 2006, Morch 1006; Rev. May 1006 PRlO <br />