Tungsten ores

TUNGSTEN ORES (EN: tungsten ores; DE: Wolframerze; FR: minerais de tungstene; ES: minerales de tungsteno; RU: вольфрамовые руды) are the natural mineral formations, which are containing tungsten within such compounds and concentrations, with which their industrial usage is technically possible and economically expedient.

There are known more than 20 minerals of tungsten. Of them, there have the industrial significance only the minerals of the group of the wolframite (74-76% of the WO3), and the scheelite (80% of the WO3).

The tungsten ores often contain molybdenum, tin, beryllium, copper, bismuth in the quantity of 0.01-0.1%, and sometimes, there exist antimony, mercury, gold, silver, arsenic, sulfur, tantalum, niobium, and scandium. The majority of the accompanying components are extracted during the beneficiation into the collective or selective concentrates. According to the conditions of the forming of the deposit, they divide the tungsten ores into endogenous and exogenous. Among the endogenous deposits, they distinguish the pegmatite, skarn, greisen, and hydrothermal (venulous-veinous) genetic types of the ores, which are unified into the three ore formations: tin-tungsten, molybdenum-tungsten, and polymetallic-tungsten. Within the pegmatites, the wolframite and scheelite, which are encountered rarely, are extracted along the way during the extraction of the cassiterite, beryl, spodumene, and tantalum-niobates. The pegmatites are the sources for the forming of the eluvial-diluvial and alluvial placers, which are being developed mainly within the countries of the south-eastern Asia and Africa.

The skarn-scheelite ores are formed within the zone of the contact of the granitoid massifs with the carbonate rocks, and are represented by the slab-shaped depositions with the steep and flat embedment, and also by the complicated lenticular and tubular ore bodies. The content of the WO3 within them is 0.1-0.8%, rarely up to 1-3%; the reserves of the ore are measured from several thousands tonnes to several tens of thousands tonnes, less often to hundreds of thousands tonnes.

The greisen-wolframite ores are tightly associated with the apical parts of the granitic intrusives. Here emerge the near-roof depositions of the wolframite-containing greisens, which are often accompanied by the ore stockworks within the intrusives and above the intrusives. They have the shape of the cloak-shaped depositions, which are isometric and oval in the projection onto the horizontal plane, with the usually flat embedment; there are also noted the columnar ore bodies, and the stockworks of the irregular shape. The content of the WO3 within them is 0.1-0.4%; the reserves of the ore are estimated as the tens of thousands tonnes, and rarely as the hundreds of thousands tonnes. The hydrothermal tungsten ores are confined to the zones of the endocontact and exocontact of the granitic massifs, thus forming the extended along the strike and to the depth (up to 1 kilometre) series of the ore veins with the steep dip, and less often with the medium dip, and also the stockworks. The ore bodies are formed of the quartz-wolframite ores, and of the quartz-wolframite-cassiterite ores, often with the molybdenite, bismuthine, and beryl, and also of the quartz-scheelite ores, and of the quartz-molybdenite-scheelite ores.

The content of the WO3 is 0.5-1.5%, rarely up to 3-5%, while within the stockworks, the content is 0.1-0.3%, sometimes up to 0.5%, with the reserves, which are reaching respectively from several thousands tonnes to several tens of thousands tonnes, and from tens of thousands tonnes to hundreds of thousands tonnes.

The extraction of the ore from the tungsten deposits is performed using the underground method (the systems of the development with the layer-wise collapse, and using the horizontal layers with the shrinkage of the ore within the exhausted blocks, or with the stowing of the goaf space, for the veins, skarn and greisen depositions), and also using the opencast method (for the stockworks, skarn and greisen depositions, placers). At the open-pit mines, there is used the transport system for the development with the external forming of the dumps for the waste rock. The extraction works are mechanized by 90-95%.

The deposits of the ores of tungsten on the territory of the USSR are known within Kazakhstan, Central Asia, eastern Siberia, at the Caucasus, and at the Far East (see the Map).

The largest deposits within the foreign countries are the Sangdong within the South Korea, the Sinhuashan and Shanpin within China, the Panasqueira within Portugal, the King Island within Australia, the Chicote and Kami within Bolivia, the Flat River within Canada, the Salau within France, the Pine Creek within the USA, the Uludağ within Turkey, the Mittersill within Austria.

The worldwide (besides the socialistic countries) total reserves of the tungsten ores (in terms of the WO3) are 1448 thousand tonnes (1980). Approximately 80% of them are accounted for Australia, Canada, USA, South Korea, and Turkey. If China is taken into account (the Guangdong and Jiangxi provinces), then more than 60% of the reserves of the tungsten ores are concentrated within the countries of the south-eastern Asia, within the limits of the Pacific ocean ore belt.