Zinc mining is the process by which mineral forms of the metal zinc are extracted from the earth through mining. A zinc mine is a mine that produces zinc minerals in ore as its primary product. Common co-products in zinc ores include minerals of lead and silver. Other mines may produce zinc minerals as a by-product of the production of ores containing more valuable minerals or metals, such as gold, silver or copper. [1] Mined ore is processed, usually on site, to produce one or more metal-rich concentrates, then transported to a zinc smelter for production of zinc metal. [2]
Global zinc mine production in 2020 was estimated to be 12 million tonnes. The largest producers were China (35%), Australia (12%), Peru (10%), India (6.0%), United States (5.6%) and Mexico (5.0%), with Australia having the largest reserves. [3]
The world's largest zinc mine is the Red Dog open-pit zinc-lead-silver mine in Alaska, with 4.2% of world production. [4] [5] Major zinc mine operators include Vedanta Resources, Glencore, BHP, Teck Resources, Sumitomo, Nexa Resources, Boliden AB, and China Minmetals. [5]
Zinc deposits have been exploited for thousands of years, with the oldest zinc mine, located in Rajasthan, India established nearly 2000 years BP. [6]
Pure zinc production occurred in the 9th century AD while, earlier in antiquity zinc was primarily utilized in the alloying of copper to produce brass. [7] This is because the isolation of zinc metal from its ore poses a unique challenge. At the temperature zinc is released from its ore it also vaporizes into a gas, and if the furnace is not airtight, the gaseous zinc reacts with the air to form zinc oxide. [8] [9]
Metallic zinc smelting occurred in 9th century BC in India, followed soon by China 300 years later, and In Europe by 1738 AD. [7] The methods of smelting in China and India were most likely independently developed, while the method of smelting developed in Europe was likely derived by the Indian method. [10] [7]
The primary modern use for zinc is for coating iron and steel in order to prevent its corrosion, with nearly half of worldwide zinc production going towards that purpose. [11] Approximately 20% of the world's zinc is used in the production of brass, where zinc is alloyed with copper in between ratios of 20-40% zinc. [11] Of the remaining 30% of the global production of zinc, half is used in the production of zinc alloys, where zinc is combined with varying amounts of aluminium, and magnesium. [11] The remaining zinc is used in various other industries from agriculture as a fertilizer and human consumption as a supplement. [11]
Zinc is mined both at the surface and at depth. Surface mining of zinc, typically used for oxide ores, while underground mining yields zinc sulfide ores. [12] Some of the common methods of zinc mining are open pit mining, open stope, and cut and fill mining: [12] [8] [13] [14]
Open-pit mining : Surface mining involves the removal of waste rock from above an ore deposit before it can be extracted. Once the waste overburden is removed, ore and waste are then mined in parallel, primarily using track-mounted excavators and rubber-tired trucks. In smaller scale operations, front loaders may be used. [15]
Open Stope mining: This is a method of underground mining where ore bodies are completely removed leaving sizeable caverns (stopes) within the mine. Open stope mining leaves these caverns with no additional bracing or external support, instead the cavern walls are supported by random pillars of ore which have not been removed. [15]
Cut and Fill stoping: A method of underground mining which removes ore from below the deposit. The stope is then filled with waste rock to replace the mined out ore to support the stope walls, and to provide an elevated floor for the miners and equipment to further extract ore from the deposit. [15]
Global mine production of zinc in 2019 was 12.9 million tonnes, a 0.9% increase from 2018, with the increase primarily attributed to increased output from zinc mines located in Australia and South Africa. [16] [3]
In 2020, production of zinc is expected to rise 3.7% to 13.99 million tonnes, with the increase due to increased production of zinc by China and India. [17]
In 2019 global demand for refined zinc exceeded supply and resulted in a deficit of 0.178 million tonnes, while in 2020 there is an expected surplus of 0.192 million tonnes. [17]
Major zinc producing countries ranked by their output for 2019 are as follows: [3]
Country | Output (million tonnes) | Share of world production |
---|---|---|
China | 4.371 | 34% |
Peru | 1.404 | 11% |
Australia | 1.283 | 10% |
USA | 0.795 | 6.1% |
India | 0.712 | 5.5% |
Mexico | 0.703 | 5.4% |
Bolivia | 0.46 | 3.5% |
Canada | 0.339 | 2.6% |
Other Countries | 2.83 | 22% |
Research conducted in the health of the benthic macroinvertebrate populations in the mining areas of southeastern Missouri, a US state, have yielded a wealth of information on the effect of zinc mining and its effect on its local environment. Fish and Crayfish populations in localities near mining sites have been observed to be much lower than other populations found in reference sites; with the crayfish possessing metal concentrations within their tissues at a much greater concentration than their reference counterparts. [18] Other investigation into the effect of the health of mussel populations that reside near lead-zinc mining areas have found that the populations residing near mining areas possessed reduced biomass, and were less specious than those found in their reference sites. [19] Plant tissue have been reported to possess concentrations of metals 10-60% higher than reference. [20] Macroinvertebrate assessments of localities immediately downstream of mining activity have observed a reduction in biotic condition 10-58% and with the ecosystem having an impaired ability to support its populations when compared to other reference sites. [21]
Benthic macro-invertebrates such as crayfish and mussels represent a pathway for biomagnification, where the concentration of noxious materials within organisms at higher trophic levels accumulates as a result of consuming contaminated prey. In addition, benthic macroinvertebrate populations are frequently used as indicators of overall ecosystem health. [18] [22] [23]
Assessment of soil samples from agricultural areas near a lead-zinc mining region in Guangxi, China have observed a "Serious pollution level" of zinc in the soils of the paddy fields relatively close to the mining area and a "Moderate pollution level" in the aerated fields relatively further away. [24] The research also indicated that as a result of their Nemerow synthetic index assessment, the region under study is not fit for agricultural purposes. [24] Other investigation into the effect of zinc mining on agricultural soils in the Heilongjiang Province of China has found that the soils were "moderately contaminated" and a significant reduction in the population and diversity of the bacterial assemblages within the soils and reduced activity of soil enzymes. [25] The activity of the bacteria and enzymes aid plant matter in the uptake of nutrients, decompose decaying matter, and other ecosystem interactions. [25] Their reduction and impaired effectiveness result in poorer agricultural productivity.
The world's ten largest zinc producing mines (by tonnes of zinc) are:
Name of the mine | Owner | Production tonnes | Operations |
---|---|---|---|
Red Dog (USA) | Teck Resources | 552,400 (2019) [4] | open-pit zinc-lead-silver mine |
Rampura Agucha (India) | Vedanta Resources (64.9%) Government of India (29.5%) | 357,571 (2019) [26] | underground zinc-lead-silver mine |
Mount Isa (Australia) | Glencore | 326,400 (2019) [27] | George Fisher and Lady Loretta underground lead-zinc-silver mines |
Antamina (Peru) | BHP (33.75%), Glencore (33.75%), Teck Resources (22.5%), Mitsubishi Corporation (10%) | 303,555 (2019) [4] | open-pit copper-zinc-molybdenum mine |
McArthur River (Australia) | Glencore | 271,200 (2019) [27] | open-pit zinc-lead-silver mine |
San Cristóbal (Bolivia) | Sumitomo Corporation | 206,100 (2019) [28] | open-pit silver-lead-zinc mine |
Dugald River (Australia) | China Minmetals | 170,057 (2019) [29] | underground cut and fill stoping |
Vazante (Brazil) | Nexa Resources | 139,000 (2019) [30] | underground and open pit zinc-lead-silver mine |
Cerro Lindo (Peru) | Nexa Resources | 126,000 (2019) [30] | underground zinc-lead-copper-silver mine |
Tara (Ireland) | Boliden AB | 122,463 (2019) [31] | underground zinc-lead mine |
Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic table. In some respects, it is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+ ions are of similar size. Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest workable lodes are in Australia, Asia, and the United States. Zinc is refined by froth flotation of the ore, roasting, and final extraction using electricity (electrowinning).
Copper extraction refers to the methods used to obtain copper from its ores. The conversion of copper ores consists of a series of physical, chemical and electrochemical processes. Methods have evolved and vary with country depending on the ore source, local environmental regulations, and other factors.
Cupellation is a refining process in metallurgy in which ores or alloyed metals are treated under very high temperatures and subjected to controlled operations to separate noble metals, like gold and silver, from base metals, like lead, copper, zinc, arsenic, antimony, or bismuth, present in the ore. The process is based on the principle that precious metals typically oxidise or react chemically at much higher temperatures than base metals. When they are heated at high temperatures, the precious metals remain apart, and the others react, forming slags or other compounds.
Boliden AB is a Swedish multinational metals, mining, and smelting company headquartered in Stockholm. The company produces zinc, copper, lead, nickel, silver, and gold, with operations in Sweden, Finland, Norway, and Ireland.
The Southeast Missouri Lead District, commonly called the Lead Belt, is a lead mining district in the southeastern part of Missouri. Counties in the Lead Belt include Saint Francois, Crawford, Dent, Iron, Madison, Reynolds, and Washington. This mining district is the most important and critical lead producer in the United States.
Kidd Mine or Kidd Creek Mine is an underground base metal (copper-zinc-silver) mine 24 km (15 mi) north of Timmins, Ontario, Canada. It is owned and operated by Swiss multinational Glencore Inc. The mine was discovered in 1963 by Texas Gulf Sulfur Company. In 1981, it was sold to Canada Development Corporation, then sold in 1986 to Falconbridge Ltd., which in 2006 was acquired by Xstrata, which in turn merged with Glencore in 2013. Ore from the Kidd Mine is processed into concentrate at the Kidd Metallurgical Site, located 27 km (17 mi) southeast of the mine, which until 2010 also smelted the ore and refined the metal produced. Following the closure of the majority of the Met Site, concentrate is now shipped to Quebec for processing. Kidd Mine is the world's deepest copper-zinc mine.
Silver mining is the extraction of silver by mining. Silver is a precious metal and holds high economic value. Because silver is often found in intimate combination with other metals, its extraction requires the use of complex technologies. In 2008, approximately 25,900 metric tons of silver were consumed worldwide, most of which came from mining. Silver mining has a variety of effects on the environment, humans, and animals.
The McArthur River mine is a zinc-lead mine, situated about 70 kilometres southwest of Borroloola, near the Gulf of Carpentaria in the northeastern Northern Territory, Australia. It is operated by McArthur River Mining (MRM), a subsidiary of the Swiss mining company Glencore. Although discovered in the 1950s, when it was originally called the HYC or "Here's Your Chance" deposit, it only opened as a mine in 1995. Initially an underground mining operation, the mine has been converted to open-cut.
Mount Isa Mines Limited ("MIM") operates the Mount Isa copper, lead, zinc and silver mines near Mount Isa, Queensland, Australia as part of the Glencore group of companies. For a brief period in 1980, MIM was Australia's largest company. It has pioneered several significant mining industry innovations, including the Isa Process copper refining technology, the Isasmelt smelting technology, and the IsaMill fine grinding technology, and it also commercialized the Jameson Cell column flotation technology.
Lundin Mining Corporation is a Canadian company that owns and operates mines in Sweden, United States, Chile, Portugal and Brazil that produce base metals such as copper, zinc, and nickel. Headquartered in Toronto, the company was founded by Adolf Lundin and operated by Lukas Lundin. While it was incorporated to pursue an interest in a diamond mine in Brazil, the company re-structured and raised funds to develop the Storliden mine in Sweden. It purchased the Swedish Zinkgruvan Mine from Rio Tinto and then merged with Arcon International Resources for its Galmoy Mine in Ireland and Eurozinc for its Neves-Corvo mine in Portugal. The company subsequently purchased and operated the Eagle mine, Candelaria mine, and Chapada mine.
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:
Tajikistan has rich deposits of gold, silver, and antimony. The largest silver deposits are in Sughd Province, where Tajikistan's largest gold mining operation is also located. Russia's Norilsk nickel company has explored a large new silver deposit at Bolshoy Kanimansur. More than 400 mineral deposits of some 70 different minerals have been discovered in Tajikistan, including strontium, tungsten, molybdenum, bismuth, salt, lead, zinc, fluorspar, and mercury. These minerals have been found suitable for mining. Uranium, an important mineral in the Soviet era, remains in some quantity but is no longer being extracted. The Tajikistan Aluminium Company (TALCO), an aluminium smelter, is the country's only large-scale production enterprise in the mining sector. Tajikistan hosts the annual Mining World Tajikistan, an international exhibition on mining in Dushanbe.
Tara Mines is a zinc and lead mine near Navan, County Meath, Ireland. Tara is an underground mine where the orebody lies between 50 and 900 metres below the surface. The orebody is within the carbonate-hosted lead-zinc ore deposits of the Navan Deposit.
Environmental effects of mining can occur at local, regional, and global scales through direct and indirect mining practices. Mining can cause erosion, sinkholes, loss of biodiversity, or the contamination of soil, groundwater, and surface water by chemicals emitted from mining processes. These processes also affect the atmosphere through carbon emissions which contributes to climate change. Some mining methods may have such significant environmental and public health effects that mining companies in some countries are required to follow strict environmental and rehabilitation codes to ensure that the mined area returns to its original state. Mining can provide various advantages to societies, yet it can also spark conflicts, particularly regarding land use both above and below the surface.
Nickel mining in New Caledonia is a major sector of the New Caledonian economy. The island contains about 7.1 million tonnes of nickel reserves, about 10% of the world's total. With an annual production of 200,000 tonnes in 2020, New Caledonia was the world's fourth largest producer after Indonesia (760,000), Philippines (320,000), and Russia (280,000), followed by Australia (170,000) and Canada (150,000).
Rampura Agucha is a zinc and lead mine located on a massive sulfide deposit in the Bhilwara district of Rajasthan, India. Rampura Agucha is located 220 km (140 mi) from Jaipur. It is north of Bhilwara, and northwest of Shahpura. Rampura Agucha is 10 km (6.2 mi) southeast of Gulabpura on NH 79. The mine is owned by Hindustan Zinc Limited (HZL), and has the world's largest deposits of zinc and lead.
Mining in North Korea is important to the country's economy. North Korea is naturally abundant in metals such as magnesite, zinc, tungsten, and iron; with magnesite resources of 6 billion tonnes, particularly in the North and South Hamgyong Province and Chagang Province. However, often these cannot be mined due to the acute shortage of electricity in the country, as well as the lack of proper tools to mine these materials and an antiquated industrial base. Coal, iron ore, limestone, and magnesite deposits are larger than other mineral commodities. Mining joint ventures with other countries include China, Canada, Egypt, and South Korea.
Zinc mining in the United States produced 780,000 tonnes of zinc in 2019, making it the world's fourth-largest zinc producer, after China, Australia, and Peru. Most US zinc came from the Red Dog mine in Alaska. The industry employed about 2,500 in mining and milling, and 250 in smelting.