PERMFILE67351 - Laserfiche WebLink

Home Browse Search

West Elk Mine • Table 5 Summa of Pum in Test Data Well Date of Test Geologic Unit Tested Hole T e Pumping Rate Yield Estimated Transmissivi SOM C76 10/18/75 F Seam Cased 3 m 0.012 m/ft. 16.68 /ft. SOM C76A 10/29/75 F Seam 8 Barren Member Cased 3 gpm 0.012 gpmHt. - SOM 22-H-2 09/25/74 Barren Member Cased 0.75 m 0.003 m/ft. 2.46 rUft. SOM 22-H-3 05/19/75 F Seam Cased 1 m SOM 64 07/30/74 Barren Member O en 0.75 m 0.005 m/ft. SOM 55 06/11/74 Barren Member O en 0.75 m 0.005 m/R. SOM C35 F Seam Cased D Hole SOM 23-H1 10/08/74 B Seam Cased 1 m SG-1 11/11/76 Sylvester Gulch Alluvium Cased 1 gpm - 121 gpd/ft. R-1 11/01/75 Rollins Sandstone O en 3 m - R-1 05/26/76 Lower Coal Membe Cased 120 m 3.3 m/it. 1723 d/ft. AL-1 05/27/76 North Fork Alluvium Cased 17.4 m 498 /ft. SOM 23-H2 10/09/74 E Seam Cased 0.6 m Notes: (1) Same hole as C76 only open to Barren Member and F Seam 2 Sus ected connection with North Fork Alluvium In addition to these wells, two additional groundwater monitoring wells were completed in the Upper Coal Member in 1996. These wells include 96-27-1, completed in the E Seam, and 96-2-2, completed in the sandstone above the E Seam. Unfortunately, the well casing for 96- 27-1 collapsed between September 2001 and April 2002 (likely as a result of B Seam mining beneath it) and is no -onger functional. Pumping tests have been conducted on four wells completed in the F Seam coal within the Upper Coal Member of the Mesaverde Formation. Pumping-test analysis from well SOM-C-76 indicates a pumping rate of approximately 3 gpm could be sustained. The result of this analysis indicates that the permeability of the formation is approximately 200 feet per yeaz (2 x l0A cm/sec). This information is contained in Table 6. Factors responsible for the water level changes are unknown at this time (Mayo and Associates, 1999). No pumping or slug-test analyses have been completed on wells in the E Seam. However, a review of the hydrograph for well SOM-23-H-2 indicates that, from the time of construction in 1974 through to the present, observed water levels have consistently been at the bottom of this particulaz well. According to information obtained at the time the well was constructed, the well was producing approximately 0.6 gpm. Water level measurements of well SOM 23-H-2 in the mid 1990s indicated that water was cascading (flowing) into the well casing from above the water level bringing the suitability of this well for monitoring purposes into question. As a result, this well was removed from the monitoring program in 1998. Development mining in the E Seam to-date (August 2004) has not resulted in any groundwater inflows from either floor springs or roof drippers. Development mining that occurred in June through July of 2004 in the E Seam was to the south and southeast from the F to the B seam in mine access slopes. The roof lithology is dominated by a sandstone channel and channel splay deposits. Several prominent dilated fractures sets are present in the developed entries. No water has entered 2.04 -67 Revised November 1004 PRIO