Discovery
In 1976 the Brazilian Geological Survey detected deposits of cassiterite (tin ore) to the east of the Waimiri Atroari Indigenous Reservation. Geologists of Brazilian Geological Survey, found traces of cassiterite in 1976 in tributaries of the Pitinga River that is outside the Indian reserve. The ore was reported to assay 2.1 kg/m3, much higher than typical deposits in Rondônia to the southwest. Paranapanema, assisted by Funai and the National Department of Mineral Production, managed to have the reservation downgraded in 1981 to the Temporary Restricted Area for the Attraction and Pacification of the Waimiri Atroari Indians, with a reduced area that excluded the cassiterite deposits. Presidential decree 86.630 of 23 November 1981 removed 526,800 hectares (1,302,000 acres) from the reserve for the tin mining operations.
In 1982 the US Bureau of Mines estimated that Brazil had total reserves of 67,000 tonnes of contained tin. In 1986 the Pitinga reserves alone were estimated at 575,000 tonnes of contained tin. The Mineração Taboca concession covers 130,000 hectares (320,000 acres) in 14 lots, but as of 1992 only 7,200 hectares (18,000 acres) were being actively exploited. Primary deposits are found in the hills of the Serra da Madeira and alluvium deposits have been washed down into the forested valleys. The alluvial deposits, now exhausted, consisted of greisens associated with the Água Boa biotite granite and the Madeira niobium-tantalum-tin deposit. The coarse-grained porphyritic albite granite has intruding paleoproterozoic acid volcanic and pyroclastic rocks. It includes Rapakivi granite and Biotite granite.
Operations
The Pitinga mine began operations in 1982. Mineração Taboca built a community in the Amazon forest 300 kilometres (190 mi) from Manaus. The complex includes roads, treated water, sanitation and a housing estate with 5,000 people. It has schools, restaurants, health facilities, a bank branch, post office, telephone exchange and supermarket. In 1985 Paranapanema invested US$15 million in infrastructure upgrades, including a 10,000 kilowatt hydroelectric power plant on the Pitinga River, expected to reduce energy costs by US$4 million annually. By 1990 the mine directly employed 2,000 people, and indirectly perhaps as many as 40,000.
Trees were cleared, the river diverted and dams and ponds built before the alluvium deposits were processed. Bucketwheel excavator dredges extracted material rich in cassiterite, which was pumped through pipes to floating processing plants that separated the tin ore. The cassiterite is concentrated on site, then shipped to Mamoré Mineração e Metalurgia in the southern state of São Paulo for casting. Columbite ore is also mined, concentrated and processed on site for use in production of FeNbTa metallic alloy. Up to 1990 a total of 120,000 tonnes of metallic tin had been produced. Mamoré Mineração e Metalurgia produced 18,000 tonnes of metallic tin in 1991. About US$200 million had been invested in the Pitinga complex by then, and the mine had earned US$915 in foreign currency. The mine was thought to be the world's most productive.
In 2006 Mineração Taboca began to extract ore from primary rock in place of the alluvial deposits. Mineração Taboca and Mamoré Mineração e Metalurgia were acquired by the Peruvian company Minsur in 2008. In 2014 Minsur had plans to develop the lower deposits, thought to be the largest undeveloped tin mine in the world with deposits estimated at 420,000t. In 2014 the Pitinga mine produced 5,532 tonnes of tin-in-concentrate, and 3,256 tonnes in the first half of 2015. Net costs per tonne of tin in 2015 were US$14,481, allowing for revenues from co-production of tantalum and niobium. At the start of August 2015 water filtrations were found in the dyke of the hydroelectric plant 80 kilometres (50 mi) away that supplies power to the plant, and operations had to slow down while repairs were made.
Coltan is a dull black metallic ore from which the elements niobium and tantalum are extracted. The niobium-dominant mineral in coltan is columbite, and the tantalum-dominant mineral is tantalite.
Cassiterite is a tin oxide mineral, SnO2. It is generally opaque, but it is translucent in thin crystals. Its luster and multiple crystal faces produce a desirable gem. Cassiterite was the chief tin ore throughout ancient history and remains the most important source of tin today.
Greisen is a highly altered granitic rock or pegmatite, usually composed predominantly of quartz and micas. Greisen is formed by self-generated alteration of a granite and is a class of moderate- to high-temperature magmatic-hydrothermal alteration related to the late-stage release of volatiles dissolved in a magma during the solidification of that magma.
Mining in Brazil is centered on the extraction of iron, copper, gold, aluminum, manganese, tin, niobium, and nickel. About gemstones, Brazil is the world's largest producer of amethyst, topaz, agate and is a big producer of tourmaline, emerald, aquamarine, garnet and opal.
Burundi is a producer of columbium (niobium) and tantalum ore, tin ore, and tungsten ore, and some deposits of gold which are designated for export. Burundi has resources of copper, cobalt, nickel, feldspar, phosphate rock, quartzite, and rare reserves of uranium, and vanadium. The country is also a producer of limestone, peat, sand and gravel for domestic consumption and as building materials. As of 2005, manufacturing accounted for 8% of the country's gross domestic product.
Drakelands Mine, also known as Hemerdon Mine or Hemerdon Ball Mine, is a tungsten and tin mine. It is located 11 km northeast of Plymouth, near Plympton, in Devon, England. It lies to the north of the villages of Sparkwell and Hemerdon, and adjacent to the large china clay pits near Lee Moor. The mine had been out of operation since 1944, except for the brief operation of a trial mine in the 1980s. Work started to re-open it in 2014, but it ceased activities in 2018. It hosts the fourth largest tin-tungsten deposit in the world.
The following outline is provided as an overview of and topical guide to mining:
Alalaú River is a river forming part of the border between the Amazonas and Roraima states in north-western Brazil, a tributary of the Jauaperi River.
Camanaú River is a river of Amazonas state in north-western Brazil, a tributary of the Curiuaú River.
The Jauaperi River is a river of Amazonas state in northwestern Brazil, a tributary of the Rio Negro.
The Pitinga River is a river of Amazonas state in north-western Brazil. It empties into the Balbina Dam on the Uatumã River.
Tanco Mine or Bernic Lake mine is an underground caesium and tantalum mine, owned and since 2019 owned and operated by Sinomine Resource Group on the north west shore of Bernic Lake, Manitoba, Canada. The mine has the largest known deposit of pollucite and is also the world's largest producer of caesium.
The Manono-Kitolo mine is a former tin and coltan mine, which also contains one of the largest lithium reserves globally, in the Democratic Republic of the Congo. The mine is located in southern Democratic Republic of the Congo in Tanganyika Province. The Manono-Kitolo mine has reserves amounting to 120 million tonnes of lithium ore grading 0.6% lithium thus resulting 0.72 million tonnes of lithium.
The Motzfeldt mine is a large niobium mine located in southern Greenland in Kujalleq. Motzfeldt represents one of the largest niobium reserves in Greenland having estimated reserves of 130 million tonnes of ore grading 1% niobium and 0.04% tantalum.
The Abu Dabab mine is a large proposed mine located in the eastern part of Egypt in Red Sea Governorate. Abu Dabab represents one of the largest tantalum reserves in Egypt having estimated reserves of 39.9 million tonnes of ore grading 0.025% tantalum.
The Three Aloes mine is a large mine located in the western part of Namibia in Erongo Region. Three Aloes represents one of the largest tantalum reserves in Namibia, having estimated reserves of 13.2 million tonnes of ore grading 0.026% tantalum.
The Waimiri Atroari Indigenous Territory is an indigenous territory in the states of Amazonas and Roraima, Brazil. There has been a long history of violent conflict between the indigenous Waimiri-Atroari people and newcomers from other parts of Brazil. Since the 1960s there have been many efforts to "civilise" the Waimiri-Atroari to avoid problems with the BR-174 highway, which cuts across the territory, and with tin mines and the huge Balbina Dam. The territory is now considerably smaller, but there have been improvements in living standards.
The Morro dos Seis Lagos Biological Reserve is a biological reserve in the state of Amazonas, Brazil. It protects an inselberg in the Amazon rainforest that contains valuable minerals. Mining has been prohibited since the reserve protected, and since it is in an indigenous territory.
The Boa Vista mine is an open pit niobium and phosphate mine located near the city of Catalão in Goiás state in Brazil. Geologically, it is located on the Catalão II carbonatite complex.
