2006-06-02_PERMIT FILE - C1980007A (3)

Home Browse Search

West Elk Mine • E-Seam Litholo~ The E Seam is a thick and widespread coal deposit of high economic importance within the West Elk Mine coal lease azea. The E Seam is comprised of two coal benches, which are sepazated locally by a rock parting. The upper coal bench is informally denoted as the "EO" Bench and the lower bench as the "El" Bench (Figure 7). MCC generically uses the E Seam designation for the upper (EO) coal bench or the combined upper and lower benches, where the rock parting is less than 0.5 feet thick. The E Seam thickness is controlled by the splitting of the two coal benches (Map 18). In the central and southern portions of the coal lease area, both EO and E1 coal benches are merged to form a thick coal body ranging from 15 to 21 feet in total thickness. To the east and west of the central coal body, the E Seam splits into two distinct benches (EO and El) as the intervening rock parting thickens (Map 18). Further to the east and west, the upper (EO) bench of the E Seam maintains mineable thickness, ranging from 8.0 to 12.0 feet. The EO bench thins to its mineable thickness limit of 8.0 feet and continues splitting and thinning further to the east and west, Within the Jumbo Mountain and most of Box Canyon lease areas, the E Seam is split and comprised of several thin (<5 feet) coal benches that are separated by rock partings. In these areas, these splits collectively form the E Seam "zone" as shown on the stratigraphic cross-sections (Figure SA through Figure SF). Because of the thin and erratic nature of these coal benches, the E Seam is • considered un-mineable in the Jumbo Mountain and most of the Box Canyon lease tracts. Where the E Seam coal benches merge to form one thick seam, away from the influence of the split, the coal quality is generally good. This is because the upper (EO) bench is thicker and "cleaner" with fewer impurities than the lower (El) bench, which frequently contains bony or shaley layers. The additional seam height will also allow top and bottom coal to be left during mining, which will improve product quality by reducing out-of--seam dilution. This thicker and higher quality E 100Seam deposit was mined during the 1940's from the Oliver No. 2 mining operation (Map 18), and will likewise be mined locally within the South of Divide permit revision azea. E Seam Reserves Mineable E Seam reserves are the basis for revised mining plan and reflect longwall mining heights ranging from 8 to 14 feet, dependent upon seam thickness and other operating constants due to reserve geology. As shown on the E Seam thickness map (Map 18), the mineable E Seam reserve is bounded on the northwest, east, and south by the thinning of the uppermost, EO coal bench to 8 foot and less in thickness and the Mt. Gunnison laccolith. To the southwest, the E Seam reserve is restricted by outcrop. To the north, the E Seam is merged with the underlying D Seam and has been mined by the Oliver No. 2 Mine operation. The existing mined slopes currently used to access the B Seam from the F Seam workings aze located such that they pass through the northern-most extent of the mineable E Seam reserve. • Access to E Seam reserves will be from these slopes south to main body of the reserve and 2.04-28 Revised November 1004 PRIO