2022-09-29_PERMIT FILE - C1980007 (2)

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West Elk Mine • MCC had to implement several measures to stabilize the roof in this area and needed to re- establish the longwall setup rooms in panels 6NW and 7NW. With the completion of longwall mining in this area the panels were sealed in July 1996. Map 14 shows B Seam overburden thickness in the permit azea. Inflows resulting from the primary porosity of the impacted strata, as in the F Seam, aze associated with low overburden and fractured zones beneath drainages and near outcrops. Based on MCC 's experience in both the B and F Seams within the current permit area, these inflows were projected to range from 5 gpm to 35 gpm in the Apache Rocks permit revision azea. Using its experiences in the development mining of the B East and Box Canyon Mains, projected initial primary porosity inflows of between 5 and 25 gpm, and in the case where another fault water system is encountered, initial secondary porosity inflows of as much as several thousand gallons per minute in the eastern Apache Rocks panels and Box Canyon panels. Within portions of the current pernut azea, the B Seam lies as close as 20 feet above the upper tongue of the Rollins Sandstone, the lowest stratigraphic unit within the Mesaverde Formation. The Rollins Sandstone outcrop location is shown on Map 9, and where poorly exposed can be inferred by following the B Seam outcrop line. Water level observations indicate groundwater within the Rollins Sandstone behaves similazly to that in the Barren Member and the Upper and Lower Coal Members within the permit azea. The exception is located just north of the permit area neaz the town of Somerset where the Rollins Sandstone is in contact with the alluvium of the North Fork. Based on the data from this document and recent drilling, it is reasonable to assume that the North • Fork rechazges fractured zones in the Rollins Sandstone in that particular area. However, studies by Mayo and Koontz (2000) show that fractured portions of the Rollins Sandstone may contain very old pressurized groundwater that can contribute several thousand gallons per minute of water inflow via fault systems, when mined through. According to Mr. Dunrud (Exhibit 60), B Seam mining will impact no more than one mining height (approximately 12 feet) below the mined seam. Previous experience and observations in the current mining azea indicate no observed impacts to the Rollins Sandstone. As such, mining in the Apache Rocks and Box Canyon permit revision areas should not impact the Rollins Sandstone, except for the depressurization of the water-filled fault systems. While significant fault inflows to the mine have occurred during 1996 and 1997 as a result of development mining in the B East Mains and 145E Headgate, there is no evidence to suggest that there have been any local or regional impacts to the water resources of the B Seam. E Seam Impacts on Groundwater. Includine Two-Seam fE and B) Mining Minable portions of the E Seam aze present throughout a lazge portion of the Apache Rocks mining area and South of Divide permit revision azea. Map 18 contains updated E Seam thickness isopleths, as delineated by drilling. Sufficient minable E Seam exists over the B Seam in the western portions of the Apache Rocks mining azea so as to facilitate multi-seam mining. Within the South of Divide permit revision area, only the E Seam is of sufficient thickness and quality to support large-scale mining. The plans for one-seam (South of Divide) and 1.05.169 Revised June 1005 PRIG; Rev. March 1006