- Power shovel
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P & H 4100 XPB cable loading shovel
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]
Contents
Design
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]
Use
Shovel digging overburdenPower 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.
Operation
The shovel operates using several main motions:
- hoist - pulling the bucket up through the bank (i.e. the bank of material being dug)
- crowd - moving the dipper handle out or in to control the depth of cut and when positioning to dump
- swing - rotating the shovel between digging and dumping
- propel - moving the shovel unit to different locations or dig positions
A shovel's work cycle, or digging cycle, consists of four phases:
- digging
- swinging
- dumping
- returning
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.
Notable Examples
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 Landmark50/65 2,750 Marion 5760 Mountaineer 1956 1989 See also
References
- ^ US Department of the Treasury, IRS: Appendix I - Glossary of Mining Terms
- ^ Encyclopædia Britannica, Power Shovel
- ^ P&H Electric Shovels - Digger Capacity Range
- ^ Extreme Mining Machines, by Keith Haddock, pub by MBI, ISBN 0-7603-0918-3
Further reading
Extreme Mining Machines - Stripping shovels and walking draglines, by Keith Haddock, pub by MBI, ISBN 0-7603-0918-3
External links
Categories:- Engineering vehicles
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