A power shovel (also stripping shovel or front shovel or electric mining shovel) is a bucket-equipped machine, usually electrically powered, used for digging and loading earth or fragmented rock and for mineral extraction.[1]
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Shovels normally consist of a revolving deck with a power plant, driving and controlling mechanisms, usually a counterweight, and a front attachment, such as a boom or crane which supports a handle with a digger at the end. The machinery is mounted on a base platform with tracks or wheels.[2] The bucket is also known as the dipper. Modern bucket capacities range from 8 m3 to nearly 80 m3.[3]
Power shovels are used principally for excavation and removal of overburden in open-cut mining operations, though it may include loading of minerals, such as coal. They are the modern equivalent of steam shovels, and operate in a similar fashion.
The shovel operates using several main motions:
A shovel's work cycle, or digging cycle, consists of four phases:
The digging phase consists of crowding the dipper into the bank, hoisting the dipper to fill it, then retracting the full dipper from the bank. The swinging phase occurs once the dipper is clear of the bank both vertically and horizontally. The operator controls the dipper through a planned swing path and dump height until it is suitably positioned over the haul unit (e.g. truck). Dumping involves opening the dipper door to dump the load, while maintaining the correct dump height. Returning is when the dipper swings back to the bank, and involves lowering the dipper into the tuck position to close the dipper door.
| Ranking | Bucket Capacity (m3/yd3) |
Operating weight (tons)[4] |
Type | Name | Service | Scrapped |
|---|---|---|---|---|---|---|
| 138/180 | 15,000 | Marion 6360 | The Captain | 1965 | 1992 | |
| 107/140 | 9,350 | Bucyrus Erie 3850B | River King | 1964 | 1993 | |
| 99/130 | 6,850 | Bucyrus Erie 1950B | GEM of Egypt | 1967 | 1991 | |
| 96/125 | 9,338 | Marion 5960 | Big Digger | 1969 | 1989 | |
| 88/115 | 6,950 | Bucyrus Erie 3850B | The Big Hog | 1962 | 1985 (Accident) | |
| 80/105 | 7,200 | Bucyrus Erie 1950B | The Silver Spade | 1965 | 2007 | |
| 69/90 | 5,220 | Bucyrus-Erie 1850-B | Big Brutus | 1962 | Preserved as a National Landmark |
|
| 50/65 | 2,750 | Marion 5760 | Mountaineer | 1956 | 1989 |
Extreme Mining Machines - Stripping shovels and walking draglines, by Keith Haddock, pub by MBI, ISBN 0-7603-0918-3