Bagger 288

The Bagger 288 was built for the job removing overburden prior to coal mining in Tagebau Hambach (stripmine Hambach), Germany. It can excavate 240,000 tons coal or 240,000 cubic metres overburden daily – the equivalent a football field(soccer) dug to 30 m (98 ft) deep. The coal produced in one day fills 2400 coal wagons. The excavator is up to 220 m (721 ft) long and approximately 96 m (315 ft) high. The Bagger's operation requires 16.56 megawatts externally supplied electricity. It can travel 2 to 10 m (6.6 to 33 ft) per minute (0.1 to 0.6 km/h). The chassis the main section is 46 m (151 ft) wide and sits on 3 rows 4 caterpillar track assemblies, each 3.8 m (12 ft) wide. The large surface area the tracks means the ground pressure the Bagger 288 is very small (17.1 N/cm2 or 24.8 psi); this allows the excavator to travel over gravel, earth and even grass without leaving a significant track. It has a minimum turning radius approximately 100 meters, and can climb a maximum gradient 1:18.
The excavating head itself is 21.6 m in diameter and has 18 buckets each holding 6.6 cubic meters (7.9 yd³) overburden.
By February 2001, the excavator had completely exposed the coal source at the Tagebau Hambach mine and was no longer needed there. In three weeks it made a 22 kilometer (14 mile) trip to the Garzweiler mine, traveling across Autobahn 61, the river Erft, a railroad line, and several roads. The move cost nearly 150 million German marks and required a team seventy workers. Rivers were crossed by placing large steel pipes for the water to flow through and providing a smooth surface over the pipes with rocks and gravel. Special grass was seeded to smooth its passage over valuable terrain. Moving Bagger 288 in one piece was more economical than disassembling the excavator and moving it piece by piece.