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Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. Exploitation of these deposits for raw material is based on the economic viability of investing in the equipment, labor, and energy required to extract, refine and transport the materials found at the mine to manufacturers who can use the material.
Kimberlite is an igneous rock, which sometimes contains diamonds. It is named after the town of Kimberley in South Africa, where the discovery of an 83.5-carat (16.70 g) diamond called the Star of South Africa in 1869 spawned a diamond rush and the digging of the open-pit mine called the Big Hole. Previously, the term kimberlite has been applied to olivine lamproites as Kimberlite II, however this has been in error.
In geology, a placer deposit or placer is an accumulation of valuable minerals formed by gravity separation from a specific source rock during sedimentary processes. The name is from the Spanish word placer, meaning "alluvial sand". Placer mining is an important source of gold, and was the main technique used in the early years of many gold rushes, including the California Gold Rush. Types of placer deposits include alluvium, eluvium, beach placers, aeolian placers and paleo-placers.
A gravel pit is an open-pit mine for the extraction of gravel. Gravel pits often lie in river valleys where the water table is high, so they may naturally fill with water to form ponds or lakes. Old, abandoned gravel pits are normally used either as nature reserves, or as amenity areas for water sports, landfills and walking. In Germany former gravel or sand pits that have filled up with water are known as Baggersee and popular for recreational use. In addition, many gravel pits in the United Kingdom have been stocked with freshwater fish such as the common carp to create coarse fishing locations. Gravel and sand are mined for concrete, construction aggregate and other industrial mineral uses.
Knorringite is a mineral species belonging to the garnet group, and forms a series with the species pyrope. It was discovered in 1968 in the Kao kimberlite pipe in the Butha-Buthe District of Lesotho and is named after Oleg Von Knorring, a professor of mineralogy at the University of Leeds in England.
Mining is the biggest contributor to Namibia's economy in terms of revenue. It accounts for 25% of the country's income. Its contribution to the gross domestic product is also very important and makes it one of the largest economic sectors of the country. Namibia produces diamonds, uranium, copper, magnesium, zinc, silver, gold, lead, semi-precious stones and industrial minerals. The majority of revenue comes from diamond mining. In 2014, Namibia was the fourth-largest exporter of non-fuel minerals in Africa.
The following outline is provided as an overview of and topical guide to mining:
Mining in the United Kingdom produces a wide variety of fossil fuels, metals, and industrial minerals due to its complex geology. In 2013, there were over 2,000 active mines, quarries, and offshore drilling sites on the continental land mass of the United Kingdom producing £34bn of minerals and employing 36,000 people.
The geology of Burkina Faso is dominated by Precambrian rocks of the Guinea Rise, a dome of Archaean rocks, composed largely of migmatites, gneisses and amphibolites, over which lie the greenstone belts of the early Proterozoic age. The latter are metasediments and metavolcanics assigned largely to the Birimian Supergroup, a suite of rocks in which economically significant mineralization occurs. Pre-Birimian migmatites, gneisses, and amphibolites, located under the Birimian rocks, are the oldest rocks in the country. The Birimian deposits in the southwestern part of the country are typically divided between clastic and volcano-clastic formations.
The Lomonosov mine is one of the largest diamond mines in Russia and in the world. The mine is located in the north-western part of the country in the Arkhangelsk Oblast. The mine has estimated reserves of 220 million carats of diamonds and an annual production capacity of 2 million carats.
The mining industry of Uganda, documented as early as the 1920s, witnessed a boom in the 1950s with a record 30 percent of the country's exports. It received a further boost when mining revenues increased by 48 percent between 1995 and 1997. However, the World Bank reported that the sector's contribution to gross domestic product (GDP) dropped from 6 percent during the 1970s to below 0.5 percent in 2010. Uganda's extractive industry activities have been identified by the Natural Resource Governance Institute as focused on "extraction of cobalt, gold, copper, iron ore, tungsten, steel, tin and other industrial products such as cement, diamonds, salt and vermiculite". Limestone is sold in local markets whereas gold, tin, and tungsten are major exports.
Tanzania is a land rich in minerals. Mining makes up more than 50% of the country's total exports, of which a large part comes from gold. The country has gold reserves of 10 million ounces, generating revenue of over a billion USD. Diamonds are also found in significant amounts. Since it was opened in 1940, the Williamson diamond mine has produced 19 million carats (3,800 kg) of diamonds. Gemstones, nickel, copper, uranium, kaolin, titanium, cobalt and platinum are also mined in Tanzania. Illegal mining and corruption are ongoing problems. In 2017, the government passed a series of bills aimed at increasing revenue from minerals after a scandal which caused the dismissal of the Minister for Energy and Minerals.
The mining industry of Liberia has witnessed a revival after the civil war which ended in 2003. Gold, diamonds, and iron ore form the core minerals of the mining sector with a new Mineral Development Policy and Mining Code being put in place to attract foreign investments. In 2013, the mineral sector accounted for 11% of GDP in the country and the World Bank has projected a further increase in the sector by 2017.
The mining industry of Malawi, includes a number of gemstones and other minerals.
The mining industry of Mali is dominated by gold extraction which has given it the ranking as the third largest in Africa. Artisanal miners play a large part in the mining of diamonds. The other minerals extracted are rock salt and semiprecious stones. Phosphates are mined in the Tilemsi Valley. In 2013, gold exports were of the order of 67.4 tonnes, nearly a 50% increase over the production in 2012 which is attributed mainly to the contribution of 20.7 tonnes made by artisanal mining. Gold, followed by cotton, is the top export item making a large contribution to the economy of the country.
The mining industry of Senegal is mainly centred on the production of phosphates and industrial limestone. Senegal is one of the leading producers of phosphates in the world, accounting for about 6% of exports in 2006, and deposits are of a particularly high quality. In the coastal region of the country, titanium-bearing minerals have been found and the reserve is estimated at 10 million tons. The mineral sector's exports accounts for 20% of total exports of the country and constitutes 20% of the GDP.
The mining industry of Sudan was mostly driven by extraction fuel minerals, with petroleum accounting for a substantial contribution to the country's economy, until the autonomous region of Southern Sudan became an independent country in July 2011. Gold, iron ore, and base metals are mined in the Hassai Gold Mine. Chromite is another important mineral extracted from the Ingessana Hills. Other minerals extracted are gypsum, salt, and cement. Phosphate is found in Mount Kuoun and Mount Lauro in eastern Nuba. Reserves of zinc, lead, aluminium, cobalt, nickel in the form of block sulfides, and uranium are also established. Large reserves of iron ore have been established.
The geology of Liberia is largely extremely ancient rock formed between 3.5 billion and 541 million years ago in the Archean and the Neoproterozoic, with some rocks from the past 145 million years near the coast. The country has rich iron resources as well as some diamonds, gold and other minerals in ancient sediment formations weathered to higher concentrations by tropical rainfall.
The geology of Lesotho is built on ancient crystalline basement rock up to 3.6 billion years old, belonging to the Kaapvaal Craton, a section of stable primordial crust. Most of the rocks in the country are sedimentary or volcanic units, belonging to the Karoo Supergroup. The country is notable for large fossil deposits and intense erosion due to high rainfall and a rare case of southern African glaciation during the last ice age. Lesotho has extensive diamonds and other natural resources and has the highest concentration of kimberlite pipes anywhere in the world.
The geology of Namibia encompasses rocks of Paleoproterozoic, Mesoproterozoic and Neoproterozoic and Paleozoic to Cenozoic age. About 46% of the countryʼs surface are bedrock exposure, while the remainder is covered by the young overburden sediments of the Kalahari and Namib deserts.
References
- 1 2 3 4 "2011 Minerals Yearbook" (PDF). U.S. Department of the Interior:U.S. Geological Survey. Retrieved 26 May 2015.
- 1 2 3 Survey 2011, p. 20.
- 1 2 3 4 (PDF) https://www.centralbank.org.ls/images/Publications/Research/Reports/MonthlyEconomicReviews/2012/July%202012%20ER%20-%20final.pdf.
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