Continuous Excavator

a continuousaction earthwork machine with a rotary working element. Enclosed and open wheel-type rotors have become most common. The latter type permits high rotational speeds for the rotor. The diameters of rotary wheels vary from 2 to 18 m, and bucket capacities are between 20 and 4,000 liters. Most continuous excavators are crawler-mounted; those that work in combination with transport and dumping bridges are moved by railroad. In the USSR, powerful continuous excavators are mounted on roller-conveyors atop a special platform that runs on railroad tracks.

The productivity of continuous excavators reaches 12,000–15,000 cu m/hr. Continuous excavators are used in mine pits for stripping and extraction work with loose, medium-hard, and frozen rock and for stone coal, which is worked with continuous excavators capable of a high cutting force. Continuous excavators permit efficient, selective excavation of thin layers and various interlayers of useful minerals. Trenching machines are used to dig small channels and trenches up to 3 m deep.