Black Thunder and Coal Creek mines

7th May 1999 By: System Author

Name: Black Thunder and Coal Creek Location: The mines lie in north-east Wyoming’s Powder River basin and are located 28 miles apart, near Gillette, Wyoming in North America Brief description: Black Thunder is America’s largest producing coal mine. The two mines produce more than 45-million tons a year, representing 5% of the coal produced in the US. The coal seam at Black Thunder averages more than 68 ft in thickness.

Brief history: Mining operations started in 1977 at Black Thunder, and in 1982 at Coal Creek. Construction began in 1976 with the installation of crushing, conveying, sampling and high-speed train-loading systems. Today, all plant processes are computer-controlled, including the new precision loadout systems and the high-tech near-pit crushing and conveying system constructed in 1989 Products: Coal Mining method: Prior to mining, 5 ft of topsoil is removed and stockpiled. The mining is carried out by ‘cast blasting’ to fragment the remaining overburden and to cast 30% or more of this soil and rock layer into the adjacent, previously-mined area in the reclamation process.

Draglines, dozers, shovels and trucks are then used to export the coal seam.

Thunder Basin owns and operates three draglines. Ursa Major, the largest of the three, is a BE 2570 WS model weighing 14,7-million pounds. The dragline was assembled on location over three years at a cost of US$50-million and its 360 ft boom carries a 160 cubic yard bucket. Thor, a model BE 1570 W, weighs 8-million pounds and features a 320 ft boom and a 91 cubic yard bucket. The third, called Walking Stick, is a BE 1300 W. It was originally built at Coal Creek but was transported across the prairie to Black Thunder, over 30 days in the winter of 1991. Weighing 4,5-million pounds, the dragline has a 45 yard bucket and its boom is 302 ft long.

To reach the coal seam at Black Thunder, draglines remove from 50 ft to 250 ft of overburden, scooping up some 160 cubic yards at a time.

Blast holes are drilled to expose the coal, after which the coal is ‘shot’ to loosen it for ease of loading and transporting by the shovels and the trucks.

To produce 45-million tons of coal, 170 miles of blast holes are drilled and 150-million pounds of explosives are used each year to blast both the coal and the overburden.

Electric shovels load the coal into 240 t haul trucks where it is carried to crushers necessary to reduce it to two inches in size.

A conveyor then carries the coal more than two miles to storage and loading facilities.

Two entirely separate crushing and conveying streams can operate simultaneously to ensure timely delivery to customers. Three state-of-the-art high-speed precision load-out facilities allow Black Thunder to load as many as 1 540 rail cars in a 24 hour period Reserves: Coal at Coal Creek comes from two seams with a combined thickness of about 33 ft. About 300-million tons of low-sulphur in-place coal reserves are present