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West Elk Mine <br />2.04-32 Rev. 11/04- PR10, 04/06- PR10, 09/07- PR12, 10/08- PR14; 01/22- MR459 <br />reduced seam thickness, poor roof conditions, and rock partings degraded product quality <br />sufficiently to make continued mining of the F Seam uneconomic. Portions of the West Elk F <br />Seam mine are used to access the active B Seam mining operations, however, there are no plans <br />to produce coal from the F Seam in the future. <br /> <br />The F Seam and adjacent strata gently dip to the northeast at approximately 3.5 degrees (Map <br />21). The strike also changes to east-west and the dip flattens to approximately one degree to the <br />north in the Box Canyon permit revision area. The F Seam outcrops on the northern side of the <br />coal lease area along the North Fork, on the western side of the lease block on Jumbo Mountain, <br />and along the South and Dry Forks of Minnesota Creek. The best exposures are along the west <br />and south-facing escarpments from just north of the Dry Fork of Minnesota Creek and to the <br />south of Lick Creek. Limited exposures of the F Seam area occur along the northern portions of <br />Sylvester Gulch. The remainder of the outcrop is covered by vegetation and soils. Burn areas <br />occur predominantly on south and west-facing slopes. Burn is not extensive or continuous along <br />the outcrop. <br /> <br />F Seam Lithology <br /> <br />The F Seam is a relatively thick and widespread coal deposit within the West Elk Mine coal lease <br />area. This seam typically occurs as a single coal bench, although locally, partings do occur within <br />the seam. Within the coal lease area, the F Seam typically ranges from 5 to 9 feet in thickness and <br />averages around 7 feet (Map 22). Most of the thickness variability occurs in the southern portion of <br />the leased area. Within the permit area, the F Seam is persistent in thickness, however, abrupt local <br />reductions in seam thickness occur where overlying channel deposits have scoured into the <br />underlying coal. <br /> <br />Although the F Seam is generally represented as a single, clean coal bench, bony or shaley <br />partings or other impurities often occur within it. When shale partings do exist, they are <br />commonly located in the lower half of the coal seam. Such shale partings were encountered <br />within the West Elk Mine, which degraded product quality. Bone horizons also occur, <br />particularly at the top and the bottom of the coal seam. <br /> <br />F Seam Reserves <br /> <br />Although the F Seam coal deposit is marginally thick (avg. 7.0 feet) within the coal lease area, <br />previous attempts to produce coal from the F Seam have proven to be uneconomic. Localized <br />scouring by overlying channel deposits and areas where partings thicken near the base of the <br />seam, served to further reduce the full seam thickness. The limited seam height was worsened <br />by poor roof conditions and as a result, product quality was degraded, eliminating any <br />competitive advantages and making mining of the F Seam unprofitable. Based upon past mining <br />experience and because economic recoverability is a reserve criterion, reserves have not been <br />estimated for the F Seam, nor are there plans to produce coal from this seam in the future. <br /> <br />F Seam Overburden <br /> <br />Within the West Elk Mine coal lease area, an average of about 700 feet of strata overlie the F Seam <br />(Map 23). This interval ranges from 0 to 1,500 feet thick. The lithologies within the overburden