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West Elk Mine sustained supply source. Presently, the only sustained inflows to the mine are from fault systems • encountered in the Rollins Sandstone below the B Seam. Amore thorough discussion of these fault systems can be found later in this section. There aze no domestic, stock, commercial or industrial groundwater wells and one irrigation well owned by MCC within the permit area. This lack of wells adequately reflects the resource potential of the groundwater beneath the mine property, with the exception of the fault systems described in this section. The CHIA, Box Canyon leasing action Decision Document by BLM and the West Elk Mine permit, including revisions and renewals, stress the lack of groundwater (and groundwater use) at the mine and surrounding properties. Domestic water for mine use is supplied by surface water from the North Fork. There are essentially three ways in which mining activities at West Elk Mine can affect groundwater quantity. These include: (1) the construction of mine entries, (2) the direct mining of the coal (this includes the effect of roof collapse and mine subsidence on water-bearing formations above the coal and the interception groundwater in damaged fault zones), and (3) the storage of water in previously mined and sealed portions of the mine. These are discussed in turn. Construction of Mine Entries Access to the B Seam is by two sloped entries driven from the F Seam South Main Intakes. Access to mining within the current permit and South of Divide permit revision azeas, and . subsequent mine development, is also planned via these same sloped entries. Mine exhaust air is currently routed westwazd through the B Seam to the Lone Pine ventilation fan, as well as through the F Seam, via aninter-seam ventilation raise, then to the Sylvester Gulch ventilation fan. Mine intake air enters the mine at three locations: (1) F Seam Portals, (2) Lone Pine Portals, and (3) Shaft #3 in Sylvester Gulch. The lazgest of these ventilation facilities is located in Sylvester Gulch where two large diameter shafts serve both present and future intake and return ventilation needs for the B Seam and E Seam mining, respectively. Additional information about the Sylvester Gulch ventilation facility can be found in Exhibit 69. No significant groundwater was encountered during slope or shaft excavation at West Elk Mine. However, awater-bearing fault with approximately 5 feet of vertical displacement was encountered at the bottom of the access slope in the B Seam in late 1990. When encountered approximately 100 gpm issued from the mine floor. Discharge from the fault declined rapidly and the groundwater system was not investigated due to the lack of notable chazacteristics (i.e., elevated temperature, odor, etc.). Aerial photo studies coupled with subsurface structural data indicate the entry slopes and ventilation shaft are not located in an area which has significant identifiable fracture zones and, as such, significant inflows have not been induced. The F Seam South Main Intakes were completed in 1982 and consist of five entries. Prior to construction of these entries, and as an effort to enhance MCC's understanding of the area groundwater system, piezometers were installed in the colluvial/landslide strata immediately upslope of the entries. Based on data from construction of these piezometers, the thickest 2.05-206 Revised November 2004 PRIO