Ursa Major, a Bucyrus Erie 2570WS dragline is the biggest dragline excavator as of now being used in North America.

The Black Thunder warm coal mine, situated in the Southern Powder River Basin of Wyoming, opened in 1977 and for a long time was the biggest single coal operation on the planet. It is additionally the principal coal mine on the planet to transport one billion tons of coal.

Dark Thunder works a few individual open pits inside its extended concession zone, utilizing five huge draglines for overburden taking care of. The dragline armada incorporates Ursa Major, the biggest of the three, a Bucyrus-Erie (B-E) 2570WS model measuring somewhere in the range of 6,700t. The third-biggest dragline ever fabricated, it was gathered nearby over a three-year time span at an expense of $50m.



Its 110m-long blast conveys a 122m³ pail. Of alternate draglines, Thor, a B-E 1570W, has a 97.5m blast and a 69m³ can, while Walking Stick is a B-E 1300W with a 92m blast and a 34m³ pail. Initially worked at Coal Creek, another Arch Coal property where generation was stopped in 2000, it was tramped over the prairie to Black Thunder late 1991.