Mining is the 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 agricultural processes, or feasibly created artificially in a laboratory or factory. Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. The ore must be a rock or mineral that contains valuable constituent, can be extracted or mined and sold for profit. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water.
Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique of extracting rock or minerals from the earth from an open-air pit, sometimes known as a borrow.
Placer mining is the mining of stream bed (alluvial) deposits for minerals. This may be done by open-pit or by various surface excavating equipment or tunneling equipment.
Mining in the engineering discipline is the extraction of minerals from underneath, open pit, above, or on the ground. Mining engineering is associated with many other disciplines, such as mineral processing, exploration, excavation, geology, and metallurgy, geotechnical engineering and surveying. A mining engineer may manage any phase of mining operations, from exploration and discovery of the mineral resources, through feasibility study, mine design, development of plans, production and operations to mine closure.[citation needed]
Prospecting is the first stage of the geological analysis of a territory. It is the search for minerals, fossils, precious metals, or mineral specimens. It is also known as fossicking.
Gold mining is the extraction of gold by mining.
Gold prospecting is the act of searching for new gold deposits. Methods used vary with the type of deposit sought and the resources of the prospector. Although traditionally a commercial activity, in some developed countries placer gold prospecting has also become a popular outdoor recreation. Gold prospecting has been popular since antiquity. From the earliest textual and archaeological references, gold prospecting was a common thread for gaining wealth.
Hydrometallurgy is a technique within the field of extractive metallurgy, the obtaining of metals from their ores. Hydrometallurgy involve the use of aqueous solutions for the recovery of metals from ores, concentrates, and recycled or residual materials. Processing techniques that complement hydrometallurgy are pyrometallurgy, vapour metallurgy, and molten salt electrometallurgy. Hydrometallurgy is typically divided into three general areas:
Gold extraction is the extraction of gold from dilute ores using a combination of chemical processes. Gold mining produces about 3600 tons annually, and another 300 tons is produced from recycling.
Heap leaching is an industrial mining process used to extract precious metals, copper, uranium, and other compounds from ore using a series of chemical reactions that absorb specific minerals and re-separate them after their division from other earth materials. Similar to in situ mining, heap leach mining differs in that it places ore on a liner, then adds the chemicals via drip systems to the ore, whereas in situ mining lacks these liners and pulls pregnant solution up to obtain the minerals. Heap leaching is widely used in modern large-scale mining operations as it produces the desired concentrates at a lower cost compared to conventional processing methods such as flotation, agitation, and vat leaching.
A rocker box is a gold mining implement for separating alluvial placer gold from sand and gravel which was used in placer mining in the 19th century. It consists of a high-sided box, which is open on one end and on top, and was placed on rockers.
Gold became highly concentrated in California, United States as the result of global forces operating over hundreds of millions of years. Volcanoes, tectonic plates and erosion all combined to concentrate billions of dollars' worth of gold in the mountains of California. During the California Gold Rush, gold-seekers known as "Forty-Niners" retrieved this gold, at first using simple techniques, and then developing more sophisticated techniques, which spread around the world.
Liquation is a metallurgical method for separating metals from an ore or alloy. The material must be heated until one of the metals starts to melt and drain away from the other and can be collected. This method was largely used to remove lead containing silver from copper, but it can also be used to remove antimony from ore minerals, and refine tin.
A gold dredge is a placer mining machine that extracts gold from sand, gravel, and dirt using water and mechanical methods.
The following outline is provided as an overview of and topical guide to mining:
Recreational gold mining and prospecting has become a popular outdoor recreation in a number of countries, including New Zealand, Australia, South Africa, Wales, in Canada and in the United States especially. Recreational mining is often small-scale placer mining but has been challenged for environmental reasons. The disruption of old gold placer deposits risks the reintroduction of post gold rush pollution, including mercury in old mining deposits and mine tailings.
A metallurgical assay is a compositional analysis of an ore, metal, or alloy, usually performed in order to test for purity or quality.
Dry blowing is a method to extract gold particles from dry soil without the use of water. A machine specialized to use this method is known as a dry blower. It is a form of winnowing.
Non-ferrous extractive metallurgy is one of the two branches of extractive metallurgy which pertains to the processes of reducing valuable, non-iron metals from ores or raw material. Metals like zinc, copper, lead, aluminium as well as rare and noble metals are of particular interest in this field, while the more common metal, iron, is considered a major impurity. Like ferrous extraction, non-ferrous extraction primarily focuses on the economic optimization of extraction processes in separating qualitatively and quantitatively marketable metals from its impurities (gangue).
The Wilfley Table is commonly used for the concentration of heavy minerals from the laboratory up to the industrial scale. It has a traditional shaking (oscillating) table design with a riffled deck. It is one of several brands of wet tables used for the separation and concentration of heavy ore minerals which include the Deister Table and Holman Table, all built to handle either coarse or fine feeds for mineral processing.
