REV07929 - Laserfiche WebLink

Home Browse Search

West Elk Mine total replacement of the annual streamflow generated in the Dry Fork basin. For these reasons, impacts to the Dry Fork of Minnesota Creek will be minimal due to Band/or E Seam mining. Mining in the Box Canyon perrnit azea will not measurably impact the surface water hydrologic balance of the North Fork. As previously stated, 100 percent of the mining azea has a B Seam overburden thickness of more than 500 feet, thus all but eliminating the possibility of surface water capture by the mine workings. 3. Based on the B Seam mining plan, in the current permit, which includes the Box Canyon permit revision area, it is not anticipated that there will be direct mining impacts to Sylvester Gulch. In summary, based on the small amount of surface flow that occurs annually, the low probability of surface cracking due to subsidence, and the depth of cover and the chazacter of the overburden materials within the permit azea, the projected mine subsidence will not significantly impact the streams. Springs/Seeps This section addresses PHCs for the springs and seeps in the current, South of Divide and West Flatiron permit revision azeas. Freauencv of Occurrence and Nature of Springs There are over 90 springs in the current permit area, as shown on Map 37. More than 90 percent of these have at least 270 feet of overburden above the highest seam to be mined. Four springs in the current permit area exhibit significant flows: Spring G-26A (peak flow during spring runoff up to 75 gpm) in Lone Pine Gulch; G-24 (up to 120 gpm) in Sylvester Gulch, and G-25 (up 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 Apache Rocks permit revision azea. There aze 15 springs that have been located in or neaz the Box Canyon pemut revision azeas, as shown on Map 37. Only low flow observations have been made at these springs. Of these, four springs aze considered perennial (10-1, 15-1, 15-2 and 24-3). The maximum observed flow rates have all been less than 10 gpm to date. Identified ephemeral springs E13-2, E13-3, E13-4 and perennial springs E13-1 and 24-3 (Map 37) aze outside the azea to be affected by subsidence in the West Flatiron Lease. MCC Plans to add springs 10-1, 24-3 and E14-1 to the monitoring program as described in Section 2.04.7. The range of flow data are presented in Table 43, Exhibit 57, and in annual hydrology reports. The range of flow data is presented in Exhibit 57 and in Annual Hydrology Reports. Fifty springs/seeps have been identified in the South of Divide permit area. Most of the springs/seeps have negligible yield. Only four of the springs have been identified as perennial (WCC-24, J-7, J-2, and 35-3), of which only J-7 is within the area of mining influence. 1.OS-164 RevisedJrme 2005 PRfO