Pennsylvania Mining Complex (PAMC) is situated in the Allegheny Plateau of the NAPP coal fields region. Near-surface geology of this area primarily consists of Pennsylvanian and Lower Permian coal-bearing strata. Coal seams mined in this region are generally classified as high- to low-volatile bituminous, characterized by low-to-high sulfur content and high heating value. The Pittsburgh Seam is the only coal seam of economic interest on the property. The Pittsburgh Seam is relatively flat-lying, typically dipping less than one degree, and is located at depths ranging from approximately 300 ft to 1,400 ft below ground surface within the PAMC area. The Pittsburgh Seam coal bed is composed of three distinct and relatively consistent intervals, in order of deposition being the thick “main bench” coal, an overlying “draw slate”, and one or more “roof coal” zones. Mining methods employed at the PAMC generally necessitate extraction of the first (lowermost) roof coal zone, along with the draw slate and main bench coal. The main bench coal thickness across the PAMC area is generally between the 5.0 ft to 6.0 ft range, averaging 5.5 ft over most of the mine plan area. Isolated pockets of both thinner and thicker coal do exist, and extreme but generally isolated occurrences may range from below 1 ft to above 11 ft thick. The draw slate is a prominent, laterally persistent shale parting that immediately overlies the main bench coal. Thickness generally ranges from 0 to 2.0 ft, avera ........

PAMC is comprised of the Bailey, Enlow Fork, and Harvey underground mines. Each mine utilizes LW mining for primary production with supporting mine development performed by CM. LW mining supported by CM development has been the primary approach to mining the Pittsburgh Seam (within which PAMC operates) for decades. Mining methods utilized by the Bailey Mine, which first began LW production in 1984 and is the oldest of the PAMC’s three operations, are largely identical to those utilized at the Enlow Fork Mine and the Harvey Mine.

The LW mining method is centered around a dual-drummed coal cutting machine (shearer) that traverses the coal face of the developed LW panels.

The shearer advances through the developed LW panels by cutting a uniform slice of coal (approximately 42 in. in depth) as it travels back and forth across the length of the LW panel width (approximately 1,500 ft). Each pass or cut by the shearer completely removes the coal directly in front of the cutting drum. Hydraulically powered LW shields are used to support the immediate mine roof at the face, above the shearer. As the shearer cuts across the faceline
(advancing 42 in. at a time), the LW shields similarly advance forward. In normal supporting conditions, the canopy of the LW shield is set tightly against the roof strata using the supporting resistances of the shield’s hydraulic legs. When the shearer cuts and passes several shield units, the shield support legs for each shield ........

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