2008-03-21_PERMIT FILE - C1980007A (4)

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Vest Elk Mine Barren Member (Mesaverde Formation) The Barren Member of the Mesaverde Formation was so named because it does not contain any persistent coal seams. The formation is generally comprised of interbedded shales and lenticular sandstones with small, discontinuous coal seams with limited lateral extent. Wells that were completed in the Barren Member of the Mesaverde Formation and, included in the monitoring programawere B-32, SOM-80, SOM-13, SOM 45-111, SOM-45-H2, SW-l, SW-2, SW-3, SW-4, SW-5, and SW-6. B-32 was removed from the monitoring program in 1998 due to subsidence damage that rendered the well unusable for monitoring purposes, and the SW series of wells were removed from the program in 1999 for similar reasons. Wells SOM 45- Hl and SOM 45-H2 have both been affected by the underlying longwall mining of Panel 13. The well casing in SOM 45-H1 collapsed between June and September 2002 and this well in no longer functional as a monitoring well. The water level in SOM 45-H2 has dropped considerably over the past several years indicating a lack of stabilization in the area since mining ceased in 2000-2001 or poor recharge to this formation as a result of several years of drought. Monitoring wells SOM-80 and SOM-13 will continue to be monitored as long as they continue to provide reliable information. Pumping tests were conducted on several presently unmonitored wells, which were completed into the Barren Member. These wells include SOM-C-76-A, SOM-22-H-2, SOM-64, and SOM-55. These tests show that the Barren Member wells exhibit a wide range of permeabilities from approximately one-half to 300 feet per year (2 x 10-7 to 3 x 10-' cm/sec). Flow rates for these wells were, however, consistently low as documented in Exhibit 17. Ohio Creek Member (Mesaverde Formation) and Wasatch Formation (Tertiary Age) Overlying the Barren Member is the Ohio Creek Member of the Mesaverde Formation and, above it, the Tertiary-age Wasatch Formation. These formations cap West Flatiron Mesa, located in the eastern portions of the permit area, and the other high mesas occurring further to the east. Like the Barren Member, these formations are generally comprised of interbedded shales and discontinuous lenticular sandstones with occasional conglomeratic zones. Drilling data indicates that these rock units are largely devoid of groundwater. The high stratigraphic position of these rock units, limited area of distribution, and outcrop exposure is not conducive to water recharge and storage. Colluvium The colluvium, which overlies the Barren Member of the Mesaverde Fonnation, is the principal water-bearing unit above the F Seam, as indicated in the Spring Geology and Hydrology Report (Watec, 1984 AHR). The colluvium consists of discrete, localized units that generally follow topography. The colluvial units recharge and discharge on a seasonal basis in response to snow- melt and precipitation events. There are presently no wells completed in the colluvium that are part of the groundwater monitoring program. 2.04-69 Revised June 2005 PRIG, March 2006; Rev. Apri12006 PR10, Sep. 2007PR12