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El Chino, located near Silver City, New Mexico, is an open-pit copper mine
El Chino, located near Silver City, New Mexico, is an open-pit copper mine

Open-pit mining, also known as opencast mining and open-cut mining, refers to a method of extracting rock or minerals from the earth by their removal from an open pit or borrow. Silver City is a town in Grant County, New Mexico, in the United States. In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific A borrow pit, also known as a sand box is a term used in Construction and Civil engineering.

The term is used to differentiate this form of mining from extractive methods that require tunneling into the earth. Mining is the extraction of valuable Minerals or other geological materials from the earth usually (but not always from an Ore body Open-pit mines are used when deposits of commercially useful minerals or rock are found near the surface; that is, where the overburden (surface material covering the valuable deposit) is relatively thin or the material of interest is structurally unsuitable for tunneling (as would be the case for sand, cinder, and gravel). A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere For minerals that occur deep below the surface—where the overburden is thick or the mineral occurs as veins in hard rock— underground mining methods extract the valued material.

Open-pit mines that produce building materials are commonly referred to as quarries. For other kinds of building materials see Hardware, Biology, Star formation. A quarry is a type of open-pit mine from which rock or Minerals are extracted People in some English-speaking countries are unlikely to make a distinction between an open-pit mine and other types of open-cast mines, such as quarries, borrows, placers, and strip mines. A borrow pit, also known as a sand box is a term used in Construction and Civil engineering. Placer mining (pronounced "plass-er" refers to the mining of alluvial deposits for Minerals This may be done by open-pit (also called open-cast Surface mining is a type of Mining in which soil and rock overlying the mineral deposit are removed

Open-pit mines are typically enlarged until either the mineral resource is exhausted, or an increasing ratio of overburden to ore makes further mining uneconomic. Mineral resource classification is the systematic organization of information on Ores and other mineral deposits which contain economic value When this occurs, the exhausted mines are sometimes converted to landfills for disposal of solid wastes. For other uses see Water treatment and Land reclamation. A landfill, also known as a dump (and historically as However, some form of water control is usually required to keep the mine pit from becoming a lake. A lake (from Latin lacus) is a Terrain feature (or Physical feature) a body of Liquid on the surface of a world that is localized to the

A coquina quarry
A coquina quarry

Contents

Extraction

Open Cut mines are dug on benches, which describe vertical levels of the hole. For the variety of clam see Donax. Coquina ( Spanish, "cockle" koʊˈkiːnə is an incompletely consolidated These benches are usually on four meter to sixty meter intervals, depending on the size of the machinery that is being used. Many quarries do not use benches, as they are usually shallow.

Most walls of the pit are generally dug on an angle less than vertical, to prevent and minimise damage and danger from rock falls. This depends on how weathered the rocks are, and the type of rock, and also how many structural weaknesses occur within the rocks, such as a fault, shears, joints or foliations. In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement Study of geological shear is related to the study of Structural geology, Rock microstructure or rock texture and fault mechanics. Foliation is any penetrative planar fabric present in rocks. Foliation is common to rocks affected by regional metamorphic compression typical of orogenic

The walls are stepped. The inclined section of the wall is known as the batter, and the flat part of the step is known as the bench or berm. The steps in the walls help prevent rock falls continuing down the entire face of the wall. In some instances additional ground support is required and rock bolts, cable bolts and shotcrete are used. A rock bolt is a long Anchor bolt, for stabilizing rock excavations which may be Tunnels or rock cuts De-watering bores may be used to relieve water pressure by drilling horizontally into the wall, which is often enough to cause failures in the wall by itself.

A haul road is situated at the side of the pit, forming a ramp up which trucks can drive, carrying ore and waste rock. An ore is a volume of rock containing components or Minerals in a mode of occurrence that renders it valuable for mining

Waste rock is piled up at the surface, near the edge of the open cut. This is known as the waste dump. The waste dump is also tiered and stepped, to minimise erosion. Erosion is the carrying away or displacement of solids ( Sediment, Soil, rock and other particles usually by the agents of currents such as wind

Ore which has been processed is known as tailings, and is generally a slurry. Tailings (also known as slimes, gangue, tailings pile, tails, leach residue, or slickens) are the materials left over This is pumped to a tailings dam or settling pond, where the water evaporates. Tailings dams can often be toxic due to the presence of unextracted sulfide minerals, some forms of toxic minerals in the gangue, and often cyanide which is used to treat gold ore via the cyanide leach process. Toxicity is the degree to which a substance is able to damage an exposed organism The term sulfide ( sulphide in British English) refers to several types of Chemical compounds containing Sulfur in its lowest Oxidation A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific A cyanide is any Chemical compound that contains the cyano group (C≡N which consists of a Carbon Atom triple-bonded to a Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79

Open-pit coal mining at Garzweiler, Germany
Open-pit coal mining at Garzweiler, Germany


Rehabilitation

After mining finishes, the mine area must undergo rehabilitation. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. Land rehabilitation is the process of returning the land in a given area to some degree of its former state after some process ( Industry, Natural disasters etc Waste dumps are contoured to flatten them out, to further stabilise them. If the ore contains sulfides it is usually covered with a layer of clay to prevent access of rain and oxygen from the air, which can oxidise the sulfides to produce sulfuric acid, a phenomenon known as acid mine drainage. The term sulfide ( sulphide in British English) refers to several types of Chemical compounds containing Sulfur in its lowest Oxidation Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and Rain is Liquid precipitation. On Earth it is the condensation of atmospheric Water vapor into drops heavy enough to fall often making it to Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Sulfuric (or sulphuric acid, H 2 S[[oxygen O]]4 is a strong Mineral acid. Acid mine drainage ( AMD) or acid rock drainage ( ARD) refers to the outflow of Acidic water from (usually abandoned Metal mines This is then generally covered with soil, and vegetation is planted to help consolidate the material. Soil, often typeset as SOiL, is a four piece rock band from Chicago Illinois United States founded by Shaun Glass Tom Schofield Tim King and Adam Zadel Eventually this layer will erode, but it is generally hoped that the rate of leaching or acid will be slowed by the cover such that the environment can handle the load of acid and associated heavy metals. There are no long term studies on the success of these covers due to the relatively short time in which large scale open pit mining has existed. It may take hundreds to thousands of years for some waste dumps to become "acid neutral" and stop leaching to the environment. The dumps are usually fenced off to prevent livestock denuding them of vegetation. Livestock is the term used to refer (singularly or plurally to a Domesticated Animal intentionally reared in an agricultural setting to produce such as Food The open pit is then surrounded with a fence, to prevent access, and it generally eventually fills up with ground water. A fence is a freestanding structure designed to restrict or prevent movement across a boundary Groundwater is Water located beneath the Ground surface in Soil pore spaces and in the Fractures of lithologic formations In arid areas it may not fill due to the deep groundwater levels.

Typical open cut grades

Gold is generally extracted in open cut mines at 1 to 2 ppm (grams per ton) but in certain cases, 0. Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 75ppm gold is economic. This was achieved by bulk heap leaching at Alkane Minerals Ltd. Peak Hill mine in western New South Wales, near Dubbo, Australia. Dubbo is a city in the Central West Region of New South Wales, Australia. For a topic outline on this subject see List of basic Australia topics.

Nickel, generally as laterite, is extracted via open cut down to 0. Nickel (ˈnɪkəl is a metallic Chemical element with the symbol Ni and Atomic number 28 2%. Copper is extracted at grades as low as 0. Copper (ˈkɒpɚ is a Chemical element with the symbol Cu (cuprum and Atomic number 29 15% to 0. 2%, generally in massive open cut mines in Chile, where the size of the resources and favorable metallurgy allows economies of scale. Chile, officially the Republic of Chile ( Spanish:) is a country in South America occupying a long and narrow Coastal strip wedged between the Metallurgy is a domain of Materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their

Materials typically extracted from open-pit mines include:

Open-pit mines

The Lavender Pit, Bisbee, Arizona
The Lavender Pit, Bisbee, Arizona

This list includes only those large open-pit mines for which an article exists in Wikipedia. Clay is a naturally occurring material composed primarily of fine-grained Minerals which show plasticity through a variable range of Water content, and For the variety of clam see Donax. Coquina ( Spanish, "cockle" koʊˈkiːnə is an incompletely consolidated In Mineralogy, diamond is the allotrope of carbon where the carbon atoms are arranged in Gravel is rock that is of a specific Particle size range In Geology, gravel is any loose rock that is larger than two millimeters (2mm In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere "Glacial" and "Glaciation" redirect here For the geological periods see Glacial period. Fluvial is used in Geography and Earth science to refer to the deposits and landforms created by the action of rivers or streams and the processes associated with Granite (ˈɡrænɪt is a common and widely occurring type of intrusive, Felsic, igneous rock. Gritstone — otherwise called Millstone grit — is a Sedimentary rock composed of coarse sand grains with inclusions of small stones Gypsum is a very soft Mineral composed of Calcium sulfate dihydrate with the Chemical formula Ca[[sulfur S]] O 4·2 Limestone is a Sedimentary rock composed largely of the Mineral Calcite ( Calcium carbonate: CaCO3 Marble is a nonfoliated Metamorphic rock resulting from the Metamorphism of Limestone, composed mostly of Calcite (a crystalline form of The M acro E xpansion T emplate A ttribute L anguage complements TAL, providing macros which allow the reuse of code across An ore is a volume of rock containing components or Minerals in a mode of occurrence that renders it valuable for mining Copper (ˈkɒpɚ is a Chemical element with the symbol Cu (cuprum and Atomic number 29 Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 Molybdenum (məˈlɪbdənəm from the Greek word for the metal " Lead " is a Group 6 Chemical element with the symbol Mo Sand is a naturally occurring Granular material composed of finely divided rock and Mineral particles Sandstone is a Sedimentary rock composed mainly of Sand -size Mineral or rock grains. Slate is a fine-grained foliated homogeneous, Metamorphic rock derived from an original Shale -type Sedimentary rock composed of Clay Bisbee is a city in Cochise County, Arizona, United States, 82 miles (132 km southeast of Tucson.

Australia

Canada

Chile

Colombia

Indonesia

Kyrgyzstan

Mongolia

Namibia

Peru

Portugal

Russia

The Udachnaya pipe in Russia.
The Udachnaya pipe in Russia. Udachnaya pipe (тру́бка Уда́чная literally lucky pipe) is a Diamond deposit in the Daldyn-Alakit Kimberlite field in Sakha

South Africa

United Kingdom

United States

See also

This is a List of Minerals for which there are Wikipedia articles Geographical list of stone used for decorative purposes in Construction and Sculpture; currently or historically produced in various countries An ore is a volume of rock containing components or Minerals in a mode of occurrence that renders it valuable for mining The various theories of ore genesis explain how the various types of mineral deposits form within the Earth's crust. Mineral resource classification is the systematic organization of information on Ores and other mineral deposits which contain economic value The Bagger 288 (Excavator 288 built by the German company Krupp for the energy and mining firm Rheinbraun, is a Bucket-wheel excavator.
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