Coal strip mine hydraulic shovel
Learn how and when to remove this template message Highwall mining is another form of surface mining that evolved from auger mining. A typical cycle includes sumping launch-pushing forward and shearing raising and lowering the cutterhead boom to cut the entire height of the coal seam. As the coal recovery cycle continues, the cutterhead is progressively launched into the coal seam for The Pushbeam system can penetrate nearly 1, feet m into the coal seam. One patented Highwall mining systems use augers enclosed inside the Pushbeam that prevent the mined coal from being contaminated by rock debris during the conveyance process. Recovery is much better than Augering, but the mapping of areas that have been developed by a Highwall miner are not mapped as rigorously as deep mined areas.
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Surface mining - Wikipedia
Bring fact-checked results to the top of your browser search. Choosing a mining method The various methods of mining a coal seam can be classified under two headings, surface mining and underground mining. Surface and underground coal mining are broad activities that incorporate numerous variations in equipment and methods, and the choice of which method to use in extracting a coal seam depends on many technological, economic, and social factors. The technological factors include, at a minimum, the number of seams, the thickness and steepness of each seam, the nature and thickness of the strata overlying the seams, the quality of the coal seams, the surface topography , the surface features, and the transportation networks available. Economic factors include energy demand and its growth, the supply and cost of alternative sources of energy, coal quality and the cost of coal preparation, the selling price of coal, advancements in technology that affect costs of production, and environmental legislation. Social factors include prior history of mining in the area, ownership patterns, availability of labour, and local or regional government support. It is a general rule that technological factors dictate a clear choice between surface and underground mining, whereas economic and social factors determine whether a coal reserve will be mined at all.
Design[ edit ] 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 crane "boom" which supports a handle "dipper" or "dipper stick" with a digger " bucket " at the end. The machinery is mounted on a base platform with tracks or wheels. Use[ edit ] Shovel digging overburden.
History[ edit ] The dragline was invented in by John W. By , Page realized that building draglines was more lucrative than contracting, so he created the Page Engineering Company to build draglines. Page built its first crude walking dragline in These used legs operated by rack and pinion on a separate frame that lifted the crane. The body was then pulled forward by chain on a roller track and then lowered again.