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The massive, fine grained, 100 feet thick Trout Creek Sandstone is the uppermost unit of the Iles <br />Formation. <br />Conformably overlying the Iles is the Williams Fork Formation. The lower unit of the Williams <br />Fork Formation is a series of interbedded shales, sandstones, sandy shales and coal. The middle <br />coal group contains the seams of economic importance. Four coal seams of economic importance <br />are found in the Williams Fork Formation. These seams are, in ascending order, the Wolf <br />Creek, Sage Creek, Wadge, and Lennox coals. Due to discontinuous occurrence of the Sage <br />Creek seam, and excessive overburden cover relative to seam thickness over much of the permit <br />area, the operator proposes to extract Wolf Creek and Sage Creek coals within only selected <br />areas of the South Extension Area. The Wadge coal will continue to be mined as part of this <br />operation. The Lennox seam is locally present in the Wadge overburden. It is usually two to <br />five feet [hick, but has been eroded away in some areas, and is not recovered by mining <br />operations. <br />The Wolf Creek coal is split into an upper and lower unit. The lower seam is about 16 feet <br />thick, while the upper is about 7.5 feet thick. Above the Wolf Creek seam within portions of the <br />permit area, and separated by 100 to 150 feet of interburden is the Sage Creek seam. The Sage <br />Creek seam ranges from 2 to 5 feet thick where it occurs in the permit area. SCC initiated <br />mining of selected areas of both the Wolf Creek seam and [he Sage Creek Seam in the South <br />Extension Area, upon approval of PR-3, in 2003. Neither seam was previously mined at Seneca <br />IIW. Overlying the Sage Creek seam is a 50 to 65 foot thick zone of sandstone interbedded with <br />shales and siltstones. Immediately above this sequence is the Wadge coal seam. The Wadge <br />coat seam is the most continuous in the area and is the only seam that was extracted prior to <br />2003. The outcrop strikes about north-south, and dips 8 to 14 degrees. The Wadge is also split <br />into upper and lower seams. The lower is two to three feet thick, and is separated from the 10 <br />foot thick upper seam by two to five feet of shales and sandstones. Overlying the Wadge is <br />about 560 feet of sandstones, shales, and coal, including the Lennox Coal Seam, which has been <br />eroded away in places. Overlying this lower unit of the Williams Fork Formation is the 130 feet <br />thick Twenty Mile Sandstone. The upper most unit of the Williams Fork Formation consists of <br />interbedded sandstones, shales, and thin coals. <br />The surficial geology of the area is composed chiefly of sedimentary rocks, of marine and <br />non-marine origin. These sedimentary rocks were formed through the transgression and <br />regression of an epicontinental sea. <br />Alluvial deposits are locally present in stream valleys, particularly along the larger streams. <br />Colluvial slides and slumps are also present in canyons and gullies throughout the area. Slide <br />bodies which could potentially affect the stability of mining related structures in the northern <br />portion of the permit area have been identified, and mitigation measures are addressed in Section <br />VII., "Backfilling and Grading" of this document. <br />Seneca II-W Findings Document 12 July 3, 2006 <br />Perini[ Renewal No. 5 <br />