By Joan Kuyek, National Co-ordinator, MiningWatch Canada
Published in the Bedford Mining Alert Newsletter, July 2004
Water is more precious than the metals that pollute it. Mining affects water in many ways:
• Acid Mine Drainage is the number one problem facing the mining industry in Canada. There is no dispute that AMD devastates fish and aquatic life, is virtually impossible to reverse with existing technology, and once started, costs millions of dollars annually to treat and can continue for centuries.
AMD occurs when sulphide-bearing minerals in rock are exposed to air and water, changing the sulphide to sulphuric acid. This acid dissolves heavy metals such as lead, zinc, copper, arsenic, cadmium, selenium and mercury into ground and surface water. Certain bacteria, naturally present, can significantly increase the rate of this reaction.
Acid mine drainage can develop at several points throughout the mining process: underground workings, open pit mine faces, waste rock dumps, tailings deposits and ore stockpiles. It can last for generations, and can travel many miles downstream.
• Radioactivity in waste rock and tailings. The uranium ore at Elliot Lake was 0.1% grade, meaning that it produced a thousand tons of waste rock for every ton of ore. The Elliot Lake Tailings Management Area is among the largest uranium production waste sites in the world, surpassed in size only by sites in southern Africa and Eastern Germany. The sites contain thousands of tons of hazardous radionuclides and heavy metals. The Denison tailings contain 15,000-30,000 tons of lead, 300 tons of cobalt, as well as 1500 tons of nickel and 15,000-30,000 tons of thorium. They are kept from release by a one metre deep cover of water held in place by a pumping station and dams which will have to be maintained for 10,000-20,000 years.
• Drawdown of water for mine processing. Mining is a major user of water in Ontario. Water is pumped from open pits and underground mines such as Aquarius and the proposed Montcalm Mine in order to “dewater” them to allow mining to proceed. Water is used to wash the ore, and in milling and refining processes. Water is used to slurry tailings from the mill to tailings management areas, and is frequently used as a water cover for acid-generating tailings. Clean water goes in, and a lesser amount of contaminated water is discharged, often to a different water system.
The Agrium phosphate mine expansion on the Constance Lake traditional territory intends to remove an entire lake and create a new one. In a survey of water taking permits in one district in northeastern Ontario, 77% of the permits issued within one year were for mining purposes. Not all the permits included limits for the amount of water used, but, of those that did, average water taking was 6.4 million litres per day. North American Palladium has a permit to take water at a rate of 30 million litres per day, for a period of five years. At a national level, the mining and metal sector consumes over 2 billion cubic metres of water annually, most of this free of charge
• Extraction processes, such as the extraction of low-grade gold by cyanide heap leaching. Gold and silver from low-grade ores is extracted by heaping the rock on a protective pad and then spraying it with a cyanide solution. The cyanide binds with the gold and silver and is then piped off. However, one teaspoon of two per cent cyanide can cause death in humans, and in recent years, a string of cyanide-related mine accidents have added to community fears and concerns. Although the industry maintains that cyanide breaks down quickly in the environment, and that it is handled safely by companies, the contrary is often true. Cyanide also breaks down into compounds that are toxic to aquatic organisms and persist for long periods of time. When mine operators test for cyanide, they do not test for these breakdown compounds.
• De-watering and changing the course of water: lakes and streams are drained or re-routed to make way for mines and roads. Mining behind dikes like the Diavik Mine plans significantly changes waterways. Erosion and silting can destroy water courses over time.
• Hydro generation: Mining requires enormous inputs of energy. Often this is obtained from hydro-electric power. Dams are built across rivers and reservoirs are created to provide power for mining companies. Frequently, decaying vegetation in the reservoirs causes mercury contamination of the waterway. Salmon runs are blocked. People who use the river for food and transportation have their lives disrupted. Sometimes, water required for life downstream, dries up. Hydro lines cause further problems.
• Roads that are built to service mines not only open up wilderness that was previously pristine to recreational use, development and hunting, they occasion sedimentation and tree removal which can destroy fish habitat, Other pollutants: diesel fuel, solvents, dust, assay chemicals, explosives and garbage are all transported along them, and leaks, accidents and plain wear and tear mean that many of these pollutants end up in the water.
In Frontenac County and the rest of Canada, clean water is the most valuable resource. Life is sustained and our health and environment depend on it. Pure water is more precious than gold.