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Humans have always used materials dug from the ground,
whether stone and clay to make While bulky and more widely available materials tend
to be extracted locally, largely reflecting local population levels, rarer
materials have always had an international market. Two thirds of European
investment in Africa before the 1930s went into mining, until the sector
made up half of the continents exports. Gold and diamonds underpin
the (ill-distributed) wealth of South Africa. Rising demand for materials has created increasingly global industries, in which local demand and demographics are largely irrelevant to levels of exploitation. Today, one of the front lines of exploration for minerals is in the Asian islands of Borneo and New Guinea, which contain the worlds largest copper and gold mines, but few of the worlds people. Traded globally but produced in intense local mining areas, mineral extraction often reflects the negative social and ecological impact of global economic forces. Rising demand has driven technologists to find ways of extracting the more valuable materials from low-grade ores, with a resulting dramatic increase in the disturbance of the land. The copper industry increased production 22-fold in the 20th century, partly by extracting metal from a 0.5 percent ore, compared with a 3 percent limit at the centurys start. The industrys 99.5 percent discard of mined ore is matched by wastes of upwards of 60 percent in the mining of iron, 70 percent for manganese, and 99.75, 99.95 and 99.99 percent respectively for tungsten, zinc and gold. Canada produces 60 times more mining waste than urban refuse1. The 20th century also saw the rapid growth of new extraction industries bauxite for aluminum, uranium for nuclear weapons and power, and petrochemicals for plastics. In consequence, over the past century mining has removed an estimated
100 million people from their land and destroyed forests and farmland,
either directly for extraction or to accommodate the waste. The extraction
and refining of ores requires the use of toxic substances such as cyanide
and mercury, which are often allowed to pollute land and river systems.
It is estimated that a ton of mercury is released into the Amazon environment
for every ton of gold extracted2,
poisoning local wildlife including fish eaten by humans.
Acid emissions from Russias metal smelting have
destroyed vegetation over hundreds of square kilometers of the Arctic
Kola peninsula. The Sudbury nickel smelter in Ontario did similar damage
in Canada in the 1970s and 1980s. The South African mining industry, which
employs some 800 000 people and generates half the countrys foreign
exchange, is also responsible for around a million tons of sulfur emissions
a year. It is one of Africas largest sources of acid pollution3.
While lending itself to large-scale industrial enterprise,
mining for minerals also employs millions of artisan miners across the
world. In Latin America an estimated 1 million artisan miners are at work,
exploiting gold in particular. Mining rushes, whether involving
artisans or corporations, frequently cause social conflict, often over
pollution. Amazon gold miners have clashed with the Yanomami in the Amazon.
Mines at Bougainville and Grasberg in New Guinea have caused civil insurrection.
Such disputes are often exacerbated when governments appear to side with
mining companies against the interests of the local communities. Some refining and smelting processes require large amounts
of energy. Many of the worlds major hydroelectric dams have been
constructed to supply cheap electricity for smelting aluminum. The Hoover
dam on the River Colorado in the United States is one such example. Another
is the Akosombo dam in Ghana. Built in the 1960s to provide hydropower
to smelt bauxite for a United States company, Akosombo flooded more than
5 percent of the country and displaced 80 000 people to create the largest
artificial lake on Earth. Since the 1960s, growing environmental awareness coupled with real shortage of some strategic metals has encouraged a new trend towards recycling. Glass, aluminum, gold and iron are all recycled on a large scale. New materials have also reduced the pressure on some mineral resources glass fibers are replacing copper in cable systems, for instance. Resource managers dream of closing the loop, with 100-percent recycling. Even industries making complex products are moving towards a recycling strategy for instance the European automobile manufacturing industry, which is dedicated to making the majority of car parts recycleable. But there may be practical limits to this approach. Recycling is not
an absolute virtue. Some analysts argue that the environmental cost is
sometimes greater than the cost of starting from scratch with new raw
materials. In most instances, efforts to reduce the use of raw materials
The impact of recycling on overall mineral exploitation has so far been
small. Production of
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Copyright AAAS 2000. |