USA's Black Thunder mine: a truck and shovel operation
During 1966/1967, ARCO obtained over 2,631 hectares (6,500 acres) of federal and state coal leases, and initial exploration was started. A total of 312 coal core holes were drilled and logged to determine the reserves and quality of the coal. The results indicated that a large surface mine could be developed to exploit the substantial reserves. The application procedure for permits was started early in 1974. Thunder Basin Coal Company is mining the Wyodak-Anderson Seam where the coal is about 21 meters (69 feet) thick. It has been estimated that a total of 750,000,000 tons of coal exist with a 0.3 to 0.4 percent sulfur content and a heating value of about 8,600 Btu per pound. The seam is mined in one lift using electric shovels and trucks. There are many factors which govern the choice of either a dragline or a truck and shovel operation for removing overburden. At the Black Thunder mine the conditions which favored the choice of the truck and shovel method were topography and pit geometry. The run-of-mine coal is dumped into two 540-ton hoppers. Underground vibrating grizzly feeders (2,500 tph capacity) pass the coal into 2,500 tph primary single-roll crushers, where the ROM coal is reduced to minus 8 inches. A 72-inch-wide elevating conveyor carries the coal to a 110-ton surge hopper, and is then fed into two secondary crushers where the coal is further reduced to minus-2 inches. The system is able to handle 5,000 tons of ROM coal per hour. The total production of coal from the mine in 1978 is expected to be about 3,000,000 tons, depending on customer requirements. It is expected that in 1979 the output will rise to 8,000,000 tons, and by 1983 the full planned production of 20,000,000 tons a year will be reached. (LTN)
- OSTI ID:
- 6608573
- Journal Information:
- World Coal; (United States), Vol. 4:10
- Country of Publication:
- United States
- Language:
- English
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How western USA mine uses three methods to strip overburden. [Shovels and trucks, scraper-dozers, and dragline]