Summary:
The West Elk mining complex extracts thermal coal from the E seam. West Elk is currently working on developing the B seam at the complex.
The Mine has access to six coal seams that are stacked underground horizontally. The seams are identified alphabetically—A through F—with the A Seam being the deepest seam. The F Seam is closest to the surface and several hundred feet underground. The seams are separated by layers of shale, siltstone, and sandstone that vary in thickness from between 15 and 250 feet.
Summary:
West Elk is an underground mining complex located in Gunnison County, Colorado. The West Elk mining complex extracts thermal coal from the E seam and currently working on developing the B seam at the complex.
The mine has six portals leading into the F seam portion of the mine. The mine has a total of four ventilation shafts that supply ventilation into the B seam and E seam portions of the mine. One ventilation shaft provides exhausting ventilation to the E seam. The average seam thickness is 10 feet.
West Elk complex currently consists of a longwall, continuous miner sections and a loadout facility.
Longwall mining involves using a mechanical shearer to extract coal from long rectangular blocks of medium to thick seams. Ultimate seam recovery using longwall mining techniques can exceed 75%. In longwall mining, continuous miners are used to develop access to these long rectangular coal blocks. Hydraulically powered supports temporarily hold up the roof of the mine while a rotating drum mechanically advances across the face of the coal seam, cutting the coal from the face. Chain conveyors then move the loosened coal to an underground mine conveyor system for delivery to the surface. Once coal is extracted from an area, the roof is allowed to collapse in a controlled fashion behind the hydraulic roof supports. Depending on the depth of the cover, the seam thickness and overlying geology, the collapse of the roof can cause surface subsidence.
Description:
- Seam - E;
- Seam height - 108-168 inches;
- Cutting height - 108-156 inches;
- Panel width - 1,100 ft;
- Panel length - 3,000-7,000 ft;
- Overburden - 400-1,100 ft;
- No. of gate entries - 3;
- Depth of cut - 42 inches;
- Shearer - Joy 7LS5, double-drum ranging arm shearer with 2,360 hp installed;
- Haulage system - Jumbotrac;
- Roof support yield (tons) - HBT 1,271;
- Roof support controls (type) - HBT PMC-R;
- Face conveyor type (strand, motors) - HBT, 48-mm chain, twin strand inboard, three 1,650-hp motors;
- Face conveyor drives - HBT CST;
- Face conveyor width/speed - 1,188 mm/371 fpm;
- Stageloader type, width, speed - HBT, 1,388 mm, 464 fpm;
- Crusher - HBT;
- Electrical controls - Service Machine;
- Voltage to face - 4,160.
Room and pillar mining is effective for small blocks of thin coal seams. In room and pillar mining, a network of rooms is cut into the coal seam, leaving a series of pillars of coal to support the roof of the mine. Continuous miners are used to cut the coal and shuttle cars are used to transport the coal to a conveyor belt for further transportation to the surface. The pillars generated as part of this mining method can constitute up to 40% of the total coal in a seam. Higher seam recovery rates can be achieved if retreat mining is used. In retreat mining, coal is mined from the pillars as workers retreat. As retreat mining occurs, the roof is allowed to collapse in a controlled fashion.
Summary:
Raw coal from West Elk mine is shipping directly via the Union Pacific railroad. When required to improve the quality of some of our coal production, it is processed through the 800 ton-per-hour preparation plant. The loadout facility can load an 11,000-ton train in less than three hours.