A power shovel, also known as a motor shovel, stripping shovel, front shovel, mining shovel or rope shovel, is a bucket-equipped machine usually powered by

steam Steam is water vapor, often mixed with air or an aerosol of liquid water droplets. This may occur due to evaporation or due to boiling, where heat is applied until water reaches the enthalpy of vaporization. Saturated or superheated steam is inv ...

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electricity Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwel ...

and used for digging and loading earth or fragmented rock and for

mineral extraction Mining is the Resource extraction, extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agriculture, agricultural processes, or feasib ...

. Power shovels are a type of rope/cable excavator, where the digging arm is controlled and powered by winches and steel ropes, rather than hydraulics like in the modern hydraulic

excavator Excavators are heavy equipment (construction), heavy construction equipment primarily consisting of a backhoe, boom, dipper (or stick), Bucket (machine part), bucket, and cab on a rotating platform known as the "house". The modern excavator's ...

s. Basic parts of a power shovel include the track system, cabin, cables, rack, stick, boom foot-pin, saddle block, boom, boom point sheaves and bucket. The size of bucket varies from 0.73 to 53 cubic meters.

Design

Power shovels normally consist of a revolving deck with a power plant, drive and control mechanisms, usually a

counterweight A counterweight is a weight (object), weight that, by applying an opposite force, provides balance and stability of a machine, mechanical system. The purpose of a counterweight is to make lifting the load faster and more efficient, which saves e ...

, and a front attachment, such as a crane ("boom") which supports a handle ("dipper" or "dipper stick") with a digger ("

bucket A bucket is typically a watertight, vertical Cylinder (geometry), cylinder or Truncation (geometry), truncated Cone (geometry), cone or square, with an open top and a flat bottom that is attached to a semicircular carrying handle (grip), handle ...

") at the end. The term "dipper" is also sometimes used to refer to the handle and digger combined. The machinery is mounted on a base platform with tracks or wheels. Modern bucket capacities range from 8m³ to nearly 80m³.

Use

Power shovels are used principally for

excavation Excavation may refer to: * Archaeological excavation * Excavation (medicine) * ''Excavation'' (The Haxan Cloak album), 2013 * ''Excavation'' (Ben Monder album), 2000 * ''Excavation'' (novel), a 2000 novel by James Rollins * '' Excavation: A Mem ...

and removal of

overburden In mining, overburden (also called waste or spoil) is the material that lies above an area that lends itself to economical exploitation, such as the rock, soil, and ecosystem that lies above a coal seam or ore body. Overburden is distinct from tai ...

open-cut mining Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique that extracts rock or minerals from the earth. Open-pit mines are used when deposits of commercially useful ore or ro ...

operations; they may also be used for the loading of minerals, such as

coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal i ...

. They are the classic equivalent of excavators, and operate in a similar fashion. Other uses of the power shovel include: # Close range work. # Digging very hard materials. # Removing large boulders. # Excavating material and loading trucks. # Various other types of jobs such as digging in gravel banks, in clay pits, cuts in support of road work, road-side berms, etc.

Operation

The shovel operates using several main motions including: * Hoisting - Pulling the bucket up through the bank of material being dug. * Crowding - Moving the dipper handle in or out in order to control the depth of cut or to position for dumping. * Swinging - Rotating the shovel between the dig site and dumping location. * Propelling - Moving the shovel unit to different locations or dig positions. A shovel's work cycle, or digging cycle, consists of four phases: *1 Digging *2 Swinging *3 Dumping *4 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 track position to close the dipper door.

Giant stripping shovels

In the 1950s with the demand for coal at a peak high and more coal companies turning to the cheaper method of

strip mining Surface mining, including strip mining, open-pit mining and mountaintop removal mining, is a broad category of mining in which soil and rock overlying the mineral deposit (the overburden) are removed, in contrast to underground mining, in which ...

, excavator manufacturers started offering a new super class of power shovels, commonly called giant stripping shovels. Most were built between the 1950s and the 1970s. The world's first giant stripping shovel for the coal fields was the Marion 5760. Unofficially known to its crew and eastern Ohio residents alike as The Mountaineer,"16 Tone Mobile Shovel Take 90 Ton Bite of Earth"
''Popular Mechanics'', April 1956, p. 95. it was erected in 1955/56 near

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off of Interstate I-70. Larger models followed the successful 5760, culminating in the mid 60s with the gigantic 12,700 ton

Marion 6360 Marion 6360, known as "the Captain", was a giant power shovel built by the Marion Power Shovel company. Completed and commissioned on October 15 1965, it was one of the largest land vehicles ever built, exceeded only by some dragline and bucke ...

, nicknamed ''The Captain''. One stripping shovel, The 4,220 ton Bucyrus-Erie 1850-B known as " Big Brutus" has been preserved as a national landmark and a museum with tours and camping. Another stripping shovel, The Bucyrus-Erie 3850-B known as "Big Hog" was eventually cut down in 1985 and buried on the Peabody Sinclair Surface Mining site near the Paradise Mining Plant where it was operated. It remains there on non-public, government-owned land.

Notable examples

Ranked by bucket capacity.

References

{{Authority control Stripping shovels Engineering vehicles Maintenance of way equipment

Design

Use

Operation

Giant stripping shovels

Notable examples

See also

Further reading

References