Ursa Major (excavator)

The Ursa Major (lit. Great Bear) at Black Thunder Coal Mine, Wyoming, is the largest dragline excavator currently in use in North America and the third largest ever built. It is a Bucyrus-Erie 2570WS model and cost US$50 million. The Ursa Major was one of five large walking draglines operated at Black Thunder, with the next two largest in the dragline fleet being Thor, a B-E 1570W - which has a 97.5-metre (320 ft) boom and a 69-cubic-metre (2,400 cu ft) bucket - and Walking Stick, a B-E 1300W with a 92-metre (302 ft) boom and a 34-cubic-metre (1,200 cu ft) bucket.