2022-02-22_PERMIT FILE - C1980007 (5)

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West Elk Mine 2.04-17 Rev. 11/04- PR10; 07/18- PR15; 01/22- MR459 B Seam Lithology The B Seam typically comprises three coal benches separated by persistent rock partings. The coal benches have been designated in descending sequence as B1, B2, and B3 (Figure 6). All three benches are present in the permit area with varying thickness. In other areas of MCC’s lease holdings the minable portion of the B Seam occurs at the top of the seam where the B1 and B2 benches are closely associated and attain sufficient combined thickness. In these areas, the upper coal benches are thinly separated by a parting informally called the "Marker Parting” and formally designated as the M1 Parting. The M1 Parting in the permit area varies from 0.2’ in the north to 29.6’ in the south at hole MG-15. The M2 Parting is also present in the B Seam within the South of Divide permit area. The M2 Parting develops in the upper section of the B2 coal bench typically 1.5’ to 2.0’ below the M1 Parting, decreasing the mineable bench of coal to the lower B2 bench. The M2 Parting has been encountered previously in the B Seam reserve in the Jumbo Mountain and Box Canyon leases. Parting composition varies from bone and carbonaceous mudstone on the fringes to fine-grained siltstones and sandstones as the parting thickens. In the Box Canyon reserve, the M2 Parting at 0.5’ or greater in thickness defined the mineable boundary for longwall mining. Beneath the B2 coal bench, a thick rock parting separates the mineable portion of the B Seam from the lowermost, impure B3 coal bench (Figure 6). Because of its position near the base of the mining interval, this parting is informally called the "Lower Parting." The underlying B3 coal bench contains numerous bone and shale partings, and as a result, may not be of salable quality. This coal bench grades downward and laterally into a carbonaceous shale. The con trast in coal quality between the upper, mineable portion of the B Seam and the impure, lower bench is shown in Table 2, along with the average as -shipped quality of the B Seam from the Box Canyon reserve and the E Seam from the South of Divide coal reserves. Table 2 Average Coal Quality Upper Lower Product Quality Parameter B Seam B Seam B Seam E Seam F Seam In situ In situ Actual Projected Actual Moisture (%) 7.7 7.8 8.5 12.1 10.0 Ash (%) 7.1 16.8 9.5 7.2 9.7 BTU (%) 11,900 10,800 11,900 11,250 11,300 Sulfur (%) 0.6 0.4 0.7 0.4 0.5 Note: As Received Basis As Shipped Basis Because the coal benches split near the margins of the coal deposit, the B Seam ranges in total thickness (B1, B2, and B3) from 1.5 feet to 16.5 feet across the coal lease area (Map 13). Those areas where B Seam splitting, parting thickening, or coal bench thinning may preclude or limit