Bucket-wheel excavators (BWEs) are heavy equipment used in surface mining and civil engineering. The primary function of BWEs is to act as a continuous digging machine in large-scale open pit mining operations. What sets BWEs apart from other large-scale mining equipment, such as bucket chain excavators, is their use of a large wheel consisting of a continuous pattern of buckets used to scoop material as the wheel turns. They are among the largest vehicles ever constructed, and the biggest bucket-wheel excavator ever built, Bagger 293, is the largest terrestrial (land) vehicle in human history according to the Guinness Book of World Records.
The scale of BWEs varies drastically and is dependent on the intended application. Compact BWEs designed by ThyssenKrupp may have boom lengths as small as 6m, weigh 50 tons, and move 100 fm3/hr of earth. Their larger models reach boom lengths of 80m, weigh 13,000 tons, and move 12,500 fm3/hr. The largest BWE ever constructed is TAKRAF’s Bagger 293, which weighs 14,200 tons and is capable of moving 240,000 cubic meters of overburden every day. Excavations of 380,000 cubic meters have been recorded. The BWEs used in the United States tend to be smaller than those constructed in Germany.