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Mining operation in Peru. (Photo by R. Butler)
Environmental impact of mining in the rainforest
Gold, copper, diamonds, and other precious metals and gemstones are important resources that are found in rainforests around the world. Extracting these natural resources is frequently a destructive activity that damages the rainforest ecosystem and causes problems for people living nearby and downstream from mining operations.
In the Amazon rainforest most mining today revolves around alluvial gold deposits. Due to the meandering nature of Amazon rivers, gold is found both in river channels and on the floodplains where rivers once ran. These deposits are actively mined by large-scale operators and informal, small-scale miners. Both operators rely heavily on hydraulic mining techniques, blasting away at river banks, clearing floodplain forests, and using heavy machinery to expose potential gold-yielding gravel deposits. Gold is usually extracted from this gravel using a sluice box to separate heavier sediment and mercury for amalgamating the precious metal. While most of the mercury is removed for reuse or burned off, some may end up in rivers. Studies have found that small-scale miners are less efficient with their use of mercury than industrial miners, releasing an estimated 2.91 pounds (1.32 kg) of mercury into waterways for every 2.2 pounds (1 kg) of gold produced.
While there is no scientific consensus on mercury contamination in the Amazon, according to biologist Michael Goulding, there is evidence of mercury causing problems in other ecosystems. Elemental or inorganic mercury can be transformed (methylated) into organic forms by biological systems and enter food chains. Not only are methylated mercury compounds toxic, but highly bioaccumulative, meaning that mercury concentrations increase up the food chain. Top predators, including otters, birds of prey, and humans, will have the highest levels of mercury in their systems. Those who eat large amounts of fish are at the greatest risk.
Location of the Grasberg mine.
A Giant Mess on New Guinea
Freeport-McMoRan, based in New Orleans, has operated the Mount Ertsberg gold, silver, and copper mine in Irian Jaya, Indonesia, for over 20 years and has converted the mountain into a 600-meter hole. As documented by the New York Times and dozens of environmental groups, the mining company has dumped appalling amounts of waste into local streams, rendering downstream waterways and wetlands "unsuitable for aquatic life." Relying on large payments to military officials, the mining operation is protected by a virtual private army that has been implicated in the deaths of an estimated 160 people between 1975 and 1997 in the mine area.
Freeport estimates that it generates 700,000 tons of waste a day and that the waste rock stored in the highlands—900 feet deep in places—now covers about three square miles. Government surveys have found that tailings from the mines have produced levels of copper and sediment so high that almost all fish have disappeared from nearly 90 square miles of wetlands downstream from the operation.
Cracking down on the Freeport's environmental abuses and questionable human-rights practices has proved a challenge since the mine is one of the largest sources of revenue for the Indonesian government. An Indonesian government scientist wrote that "the mine's production was so huge, and regulatory tools so weak, that it was like 'painting on clouds' to persuade Freeport to comply with the ministry's requests to reduce environmental damage," according to a December 27, 2005, article in the New York Times.
For more take a look at "Below a Mountain of Wealth, a River of Waste" in the New York Times. The article was written by JANE PERLEZ and RAYMOND BONNER.
Other toxic compounds are used and generated in the mining process as well. Mining exposes previously buried metal sulfides to atmospheric oxygen causing their conversion to strong sulfuric acid and metal oxides, which run off into local waterways. Oxides tend to more soluble in water and contaminate local rivers with heavy metals.
Cyanide, a highly toxic compound, is also often used to separate gold from sediment and rock. While cyanide is supposed to be carefully monitored to prevent its escape into the surround environment, spills do occur—especially when there's no one around to enforce mining regulations. The effects of poisoning can be widespread, especially when a waste-holding pool overflows or breaks, as it did in Guyana in August 1995.
The Guyana spill made international headlines for its magnitude—over one billion gallons (four billion liters) of cyanide-laced waste water was released into a tributary of the Essequibo— and its effects, causing widespread die-offs of aquatic and terrestrial plant and animal life, poisoning floodplain soils used for agriculture, polluting the main source of drinking water for thousands of people, and striking a major blow to the nascent eco-tourism industry on the river. The mine, run by Golden Star Resources of Denver and Cambior of Montreal, at first tried to cover up the spill by burying fish carcasses. Six days after the spill, after locals found dead wildlife, the mine reported the accident to the Guyana government. Despite the damage inflicted by the spill, the government granted additional mining concessions on the New River shortly thereafter.
Large-scale mining operations, especially those using open-pit mining techniques, can result in significant deforestation through forest clearing and the construction of roads which open remote forest areas to transient settlers, land speculators, and small-scale miners. These settlers and miners are probably a greater threat to the tropical rainforest environment than industrial mining operations. Wildcat miners enter regions rumored to have gold deposits and clear forest in search of riches. They hunt wildlife, cut trees for building material and fuelwood, and trigger erosion by clearing hillsides and detonating explosives. Miners can also bring diseases to local indigenous populations (where they still exist) and battles over land rights. One well-documented example is the conflict between the Yanomani Indians of Northern Brazil and Venezuela and garimpeiros—illegal Brazilian miners. Reports indicated that Yanomani populations have fallen significantly since the first incursion of miners in the 1980s.
While deforestation and chemical pollution from mining can impact the rainforest environment, downstream aquatic habitats fare worse. Increased sediment loads and reduced water flows can seriously affect local fish populations.
Photos of a mining operation in the Peruvian Amazon
Cement mining puts Dominican Republic park at risk
(11/01/2009) A cement mine, granted under questionable circumstances, is putting one the Caribbean's most important forest parks at risk, warns a group working to stop the project.
Crowned sifaka population on the verge of local extinction: dispatch from the field
(09/08/2009) A small group of crowned sifaka lemurs Propithecus coronatus have been located in the corridor d’Amboloando-Dabolava, Miandrivazo district-Madagascar, but are immediately threatened with local extinction. The small, fragmented, and isolated forest shelters a group of only six adults and one baby. Interviews with local people revealed that once several groups of the species resided in the corridor, and even last year, about 20 individuals were still found there. However, within one year, the population dropped from 20 to 6 individuals.
Saving Africa's 'unicorn', the okapi
(09/02/2009) The giraffe is one of Africa's most recognizable animals, but its shy and elusive forest cousin, the okapi, was so little known that until just over a century ago the western world believed it was a mythical beast, an African unicorn. Today, a shroud of mystery still envelops the okapi, an animal that looks like a cross between a zebra, a donkey, and a giraffe. But what is known is cause for concern. Its habitat, long protected by its remoteness, was the site of horrific civil strife, with disease, famine, and conflict claiming untold numbers of Congolese over the past decade. Now, as a semblance of peace has settled over Democratic Republic of Congo (DRC), the okapi's prospects have further dimmed, for its home is increasingly seen as a rich source of timber, minerals, and meat to help the war-torn country rebuild. In an effort to ensure that the okapi does not become a victim of economic recovery, the Okapi Conservation Project (OCP) is working to protect the okapi and its habitat. Founded by John Lukas in 1987, well before the conflict, OCP today manages the Okapi Wildlife Reserve, a 13,700-square-kilometer tract of wilderness in the Ituri Forest of northeastern DRC.
Mining and biodiversity offsets in Madagascar: Conservation or 'Conservation Opportunities?'
(08/30/2009) Rio Tinto's ilmenite mine in southeastern Madagascar is among the largest on the planet. At peak capacity, its owners say, it could produce as much as 2 million tons of the stuff—worth roughly $100 a ton—each year, to be shipped off and smelted abroad. What's left of it after refining—some 60 percent of the ore that arrives from Madagascar—will be sold for $2000 a ton as titanium dioxide, a pigment used in everything from white paint and tennis court lines to sunscreen and toothpaste. At current levels of demand, the Fort Dauphin mine will provide 9 percent of the world supply over the next 40 years, amounting to more than $60 billion of titanium dioxide. Even that is a conservative estimate: demand for ilmenite has been growing at 3-5 percent annually, with major mines slated to close in coming years and few untapped sources known worldwide.
Gold mining threatens world's most infamous reptile, the Komodo dragon
(08/24/2009) A row has taken off in Indonesia over whether or not to allow gold mining near Komodo National Park, home to the infamous, venomous, and largest of all lizards, the Komodo dragon. Eight mines have currently been proposed, several have already begun exploratory work. Critics of the gold mines contend that the mining threatens the ecology of the park and the Komodo dragon, listed as Vulnerable by the IUCN.
