Mining is the extraction of valuable minerals or other geological materials from the earth from an orebody, lode, vein, seam, or reef, which forms the mineralized package of economic interest to the miner.
Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain any material that cannot be grown through agricultural processes, or created artificially in a laboratory or factory. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water.
Mining of stones and metal has been done since pre-historic times. Modern mining processes involve prospecting for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desired materials, and final reclamation of the land after the mine is closed.
The nature of mining processes creates a potential negative impact on the environment both during the mining operations and for years after the mine is closed. This impact has led most of the world's nations to adopt regulations designed to moderate the negative effects of mining operations. Safety has long been a concern as well, and modern practices have improved safety in mines significantly.
- Main article: Environmental issues with mining
Environmental issues can include erosion, formation of sinkholes, loss of biodiversity, and contamination of soil, groundwater and surface water by chemicals from mining processes. In some cases, additional forest logging is done in the vicinity of mines to create space for the storage of the created debris and soil. Contamination resulting from leakage of chemicals can also affect the health of the local population if not properly controlled. Extreme examples of pollution from mining activities include coal fires, which can last for years or even decades, producing massive amounts of environmental damage.
Mining companies in most countries are required to follow stringent environmental and rehabilitation codes in order to minimize environmental impact and avoid impacting human health. These codes and regulations all require the common steps of environmental impact assessment, development of environmental management plans, mine closure planning (which must be done before the start of mining operations), and environmental monitoring during operation and after closure. However, in some areas, particularly in the developing world, government regulations may not be well enforced.
For major mining companies and any company seeking international financing, there are a number of other mechanisms to enforce good environmental standards. These generally relate to financing standards such as the Equator Principles, IFC environmental standards, and criteria for Socially responsible investing. Mining companies have used this oversight from the financial sector to argue for some level of self-policing. In 1992, a Draft Code of Conduct for Transnational Corporations was proposed at the Rio Earth Summit by the UN Centre for Transnational Corporations (UNCTC), but the Business Council for Sustainable Development (BCSD) together with the International Chamber of Commerce (ICC) argued successfully for self-regulation instead.
This was followed by the Global Mining Initiative which was begun by nine of the largest metals and mining companies and which led to the formation of the International Council on Mining and Metals, whose purpose was to "act as a catalyst" in an effort to improve social and environmental performance in the mining and metals industry internationally. The mining industry has provided funding to various conservation groups, some of which have been working with conservation agendas that are at odds with an emerging acceptance of the rights of indigenous people – particularly the right to make land-use decisions.
Certification of mines with good practices occurs through the International Organization for Standardization (ISO). For example, ISO 9000 and ISO 14001, which certify an "auditable environmental management system", involve short inspections, although they have been accused of lacking rigorScript error.:183–4 Certification is also available through Ceres' Global Reporting Initiative, but these reports are voluntary and unverified. Miscellaneous other certification programs exist for various projects, typically through nonprofit groups.:185–6
The purpose of a 2012 EPS PEAKS paper was to provide evidence on policies managing ecological costs and maximise socio-economic benefits of mining using host country regulatory initiatives. It found existing literature suggesting donors encourage developing countries to:
- Make the environment-poverty link and introduce cutting-edge wealth measures and natural capital accounts.
- Reform old taxes in line with more recent financial innovation, engage directly with the companies, enacting land use and impact assessments, and incorporate specialised support and standards agencies.
- Set in play transparency and community participation initiatives using the wealth accrued.
Ore mills generate large amounts of waste, called tailings. For example, 99 tons of waste are generated per ton of Cu, with even higher ratios in gold mining - because only 5.3 g of Au is extracted per ton of ore, a ton of Au produces 200,00 tons of tailings. These tailings can be toxic. Tailings, which are usually produced as a slurry, are most commonly dumped into ponds made from naturally existing valleys. These ponds are secured by impoundments (dams or embankment dams). In 2000 it was estimated that 3,500 tailings impoundments existed, and that every year, 2 to 5 major failures and 35 minor failures occurred; for example, in the Marcopper mining disaster at least 2 million tons of tailings were released into a local river. Subaqueous tailings disposal is another option. The mining industry has argued that submarine tailings disposal (STD), which disposes of tailings in the sea, is ideal because it avoids the risks of tailings ponds; although the practice is illegal in the United States and Canada, it is used in the developing world.
The waste is classified as either sterile or mineralised, with acid generating potential, and the movement and storage of this material forms a major part of the mine planning process. When the mineralised package is determined by an economic cut-off, the near-grade mineralised waste is usually dumped separately with view to later treatment should market conditions change and it becomes economically viable. Civil engineering design parameters are used in the design of the waste dumps, and special conditions apply to high-rainfall areas and to seismically active areas. Waste dump designs must meet all regulatory requirements of the country in whose jurisdiction the mine is located. It is also common practice to rehabilitate dumps to an internationally acceptable standard, which in some cases means that higher standards than the local regulatory standard are applied.
Renewable energy and miningEdit
Many mining sites are remote and not connected to the grid. Electricity is typically generated with diesel generators. Due to high transportation cost and theft during transportation the cost for generating electricity is normally high. Renewable energy applications are becoming an alternative or amendment. Both solar and wind power plants can contribute in saving diesel costs at mining sites. Renewable energy applications have been built at mining sites. Cost savings can reach up to 70%.
Metal reserves and recyclingEdit
- Main article: Landfill mining
During the twentieth century, the variety of metals used in society grew rapidly. Today, the development of major nations such as China and India and advances in technologies are fueling an ever greater demand. The result is that metal mining activities are expanding and more and more of the world’s metal stocks are above ground in use rather than below ground as unused reserves. An example is the in-use stock of copper. Between 1932 and 1999, copper in use in the USA rose from 73 kilograms (161 lb) to 238 kilograms (525 lb) per person.
95% of the energy used to make aluminium from bauxite ore is saved by using recycled material. However, levels of metals recycling are generally low. In 2010, the International Resource Panel, hosted by the United Nations Environment Programme (UNEP), published reports on metal stocks that exist within society and their recycling rates.
The report's authors observed that the metal stocks in society can serve as huge mines above ground. However, they warned that the recycling rates of some rare metals used in applications such as mobile phones, battery packs for hybrid cars, and fuel cells are so low that unless future end-of-life recycling rates are dramatically stepped up these critical metals will become unavailable for use in modern technology.
As recycling rates are low and so much metal has already been extracted, some landfills now contain higher concentrations of metal than mines themselves. This is especially true with Al, found in cans, and precious metals in discarded electronics. Furthermore, waste after 15 years has still not broken down, so less processing would be required when compared to mining ores. A study undertaken by Cranfield University has found £360 million of metals could be mined from just 4 landfill sites. There is also up to 20MW/kg of energy in waste, potentially making the re-extraction more profitable. However, although the first landfill mine opened in Tel Aviv, Israel in 1953, little work has followed due to the abundance of accessible ores.
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- ↑ Bloom, M.J. & Denison, M. (2012) Environmental management for extractives, PROFESSIONAL EVIDENCE AND APPLIED KNOWLEDGE SERVICES http://partnerplatform.org/?zl177g4a
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- ↑ 5.0 5.1 5.2 US EPA. (1994). Technical Report: Design and Evaluation of Tailings DamsScript error.
- ↑ 6.0 6.1 6.2 TE Martin, MP Davies. (2000). Trends in the stewardship of tailings dams.
- ↑ Coumans C. (2002). Mining’s Problem with Waste. MiningWatch Canada.
- ↑ http://www.th-energy.net/english/platform-renewable-energy-and-mining/database-solar-wind-power-plants/
- ↑ http://www.mining.com/web/at-mining-sites-renewable-energy-systems-are-up-to-70-percent-less-expensive-than-diesel-power/
- ↑ 10.0 10.1 The Recycling Rates of Metals: A Status Report 2010, International Resource Panel, United Nations Environment Programme
- ↑ Tread lightly: Aluminium attack Carolyn Fry, Guardian.co.uk, 22 February 2008.
- ↑ Metal Stocks in Society: Scientific Synthesis 2010, International Resource Panel, United Nations Environment Programme
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- Woytinsky, W. S., and E. S. Woytinsky. World Population and Production Trends and Outlooks (1953) pp 749–881; with many tables and maps on the worldwide mining industry in 1950, including coal, metals and minerals
- Ali, Saleem H. (2003) Mining, the Environment and Indigenous Development Conflicts. Tucson AZ: University of Arizona Press.
- Ali, Saleem H. (2009) Treasures of the Earth: need, greed and a sustainable future. New Haven and London: Yale University Press
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- Geobacter Project: Gold mines may owe their origins to bacteria (in PDF format)
- Garrett, Dennis Alaska Placer Mining
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- Morrison, Tom (1992) Hardrock Gold: a miner's tale. ISBN 0-8061-2442-3
- John Milne: The Miner's Handbook: A Handy Reference on the subjects of Mineral Deposits(1894) Mining operations in the19th century.
- Aryee, B., Ntibery, B., Atorkui, E. (2003) Trends in the small-scale mining of precious minerals in Ghana: a perspective on its environmental impact (in Journal of Cleaner Production 11: 131-140)
- The Oil, gas and Mining Sustainable Community Development Fund (2009) Social Mine Closure Strategy, Mali(in )
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