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Blog postings by The Environmental Health Impacts of Mining

November 14, 2008

Raw Materials and Electronics Manufacturing

By Sarah Henderson

The mining of materials used to manufacture electronics takes a heavy toll on the environment. Mining accounts for an estimated 7- 10 percent of the world’s energy. Most of this energy comes from oil and coal and is used to power the huge machines used throughout the mining process. Recycling can reduce this amount of energy. For example, recycling copper uses only 15 – 20 percent the energy needed to mine new ore.

Mining causes impurities to be released into the air and travel into surrounding streams and groundwater. Toxics released into the air can include sulfur dioxide, nitrogen oxide and lead. In the United States, mining releases more toxics into the air than any other industry. One example of mining air pollution is in a copper, lead and zinc plan in Peru, where emissions caused almost all the children in the community to suffer from lead poisoning. Other negative impacts of mining include soil degradation and negative health impacts on mine workers.

The toxic by-products of mining include arsenic, mercury, lead and cadmium, which run off into the streams as well as the groundwater. Everywhere mining has taken place, contaminated water is pervasive. Tailings are by-products of mining that are deposited as solid waste once the valuable ores have been extracted. Tailings from copper mines contain sulfates, lead, arsenic, cadmium and zinc. When the sulfites are exposed to air or water it creates sulfuric acid, which is corrosive and toxic to aquatic life. If the sulfates mix in the water with residual copper and heavy metals, the chemical combination is toxic to wildlife and people who use the water.

The two different kinds of mines are open-pit mines and underground mines. They use a huge amount of water and energy and soil degradation. Both mines also create tailings and negatively impact the environment. Underground mines have health risks such as dust, which leads to respiratory problems in workers. Other health risks include fires and tunnel collapses.

Most metals come from open-pit mines. This results in a huge amount of waste rock and rubble. The craters formed by open-pit mines are huge and disrupts the natural topographic ecology. For example, to mine the two pounds of copper needed to produce a desktop computer has a result of 620 pounds of waste rock. Many of these mines are huge, some bigger than Bagdad. The other impact of open-pit mines are great shifts in local water supplies. If the depth of a mining pit is lower than the water table there is a risk of dewatering nearby streams and even the immediate aquifer. This happens because the pit must be pumped to keep it dry and workable, at the same time, water from this source is used for dust control as well as other mining operations.

Coltan is a material which is the major source for tantalum, which is highly heat and corrosion resistant as well as an excellent conductor of electricity. Tantalum is used in tiny capacitors, which store an electronic charge. This material is relatively rare and expensive and is used in small electronic devices such as cell phones.
While the Democratic Republic of the Congo only produces 1% of the world’s tantalum, this area is a concern due to illegal mining and smuggling which has funded military occupation in the area. This is a similar case to diamond mining in Africa in that it is very difficult to trace the material to where it was mined once it enters the international market due to a lack of an official auditable process. There is also a concern the DRC that mining will negatively impact the threatened eastern lowland gorilla.

Computer production entails the fabrication of silicon and semiconductors. While the mining of silicon has limited environmental impact, the processing of the material involves many toxic chemicals and creates numerous waste products. Silicon production is a process which is materials and energy intensive. It is not possible to recycle silicon at the chip level, because the finished product is so specific to a task. Used chips are disposed in landfills, and there is no evidence that disposing them in this way has harmful effects. Other semiconductors include germanium, gallium arsenide and indium phosphide.

Improvements have been made to limit the environmental effects of computer production. The members of the Electronics Industries Alliance created the “product material declaration program? where it is required for all materials that go into an electronic product to be declared. In the United States materials declarations are included in purchasing policies. Environmental health and safety reports show environmental improvements in silicon production including less water being used, less energy, a smaller volume of chemicals, less toxics released into the air and water and less greenhouse and ozone emissions. Recycling also plays a huge role in lessening the environmental impact of producing new electronics. The materials that can be recycled include copper, gold, zinc, silver and tantalum.

Bibliography:

High Tech Trash: Digital Devices, HIdden Toxics, and Human Trash, Elizabeth
Grossman, Island Press, 2006.

http://en.wikipedia.org/wiki/Coltan