When the gold mining industry was in its infancy in America, there were few disasters. The majority of finds being placer deposits, on the surface or in shallow streams which were panned, the dangers presented to prospectors were the practical ones of falling and breaking a limb, or possibly drowning in water too deep, while wearing heavy equipment. Only when operations moved underground, did major events involving multiple fatalities take place.
In the century between 1870 and 1970, the United States recorded 104 mining disasters which took five or more lives, for a total of 1403 people killed. However, only 25% of those were gold mining accidents. Of those 27 disasters in gold mines, 12 involved fire, the main supports being timber, and crowded bunkhouses jammed together in tinder dry conditions. Another nine disasters were attributed to cage falls, and even snowslides. The remaining six disasters involved explosions, starting in 1889 with a dynamite blast in Silver Cliff, Colorado that took ten lives. Never was it truer that "haste makes waste", as the rush to pry gold from its bed made men careless.
A prime example of this was the Moose River mine disaster of 1936, which took place in Nova Scotia, Canada. While a gold mining enjoyed a boom period from 1890-1909, producing some 26,000 troy ounces, it petered out and shut down during WWI. In 1936, a lawyer and doctor formed a new syndicate, which went in and began mining from the only source left in the tunnels- the rock pillars that had been left as roof supports. On April 12, 1936 the two owners and the timekeeper went in to inspect the workings. The tunnel collapsed on top of them. After six days of using a diamond drill, contact was made with the men, who were still alive. But lawyer Herman Magill would die just hours later. It would be another four days before the survivors were brought to the surface.
As the mining industry boomed, more and better methods were sought to harvest the gold from the ore it was embedded in. Such "advances" may have led to the greatest gold mining disasters in terms of far reaching consequences, as opposed to immediate loss of life.
First came mercury, a component in the amalgam recovery of gold. Since mercury bonds to gold, after the ore was cleaned and crushed, it was blended with mercury, the lumps of amalgam were then removed, and processed to separate the mercury from the gold. At times, this process included nitric acid as well, in which the recovered mercury sat until cleaned and was ready to use again. Eventually it got dirty beyond the miners' knowledge to "clean" it, and it was dumped into the environment, as were the small particles of mercury that clung to the gold when it was cleaned once more. Thus, gold mining has been repeatedly blamed for mercury contamination in and near mining sites that have been abandoned for years.
A monkey wrench was thrown into this theory in 1992, through the joint study by Brazilian and Canadian researchers along the Tapajos River, a major tributary to the Amazon. Brazil is one of the few countries still allowing the extraction of gold by mercury amalgam.
The surprising results were that for villages 400km downriver from active gold mining sites, the water suffered the same contamination levels as for those only 50km away. Not only that, but sediment levels were also the same. While researchers agreed that sites near to a gold mining site using mercury must come into contact with some discarded mercury, the majority of the element existing in their environment came from the ground itself, the product of volcanic activity over the million-year history of the area. With the shift in population to outlying areas that are "slashed and burned" to provide living and agricultural space, the ground is now bare, and more soil is washed into the rivers, carrying its mercury load with it. In all, they estimate that only 3% of the existing mercury contamination comes from mining.
From the threat of mercury, gold mining moved into more potentially hazardous use of cyanide to separate flakes of gold from other materials. In 1995, a dam in Georgetown, Guyana leaked the slurry from a gold mine's tailings pond into the Essequibo River for five days. Approximately 825 gallons of cyanide laced water, poured into the 600 mile long river. Solid hydrogen cyanide salt used in gold processing has been reported as lethal in concentrations as low as 2 parts per million. Dead animals and fish were swept 50 miles downstream. That stretch of the Essequibo was declared a national environmental disaster by Guyanan president, Cheddi Jagan, who noted it was not the first case of poisonous spills from the mine's tailings pond.
Bracketing the South American disaster, was the cleanup of the Summitville gold mine in Colorado, in 1993, a $170 million dollar bill from acid contamination and cyanide pollution. Then in 1997, the Pegasus Gold Corporation abandoned their site in Montana, leaving that state with another multi-million dollar cleanup.
The Mining Law of 1872 was established primarily to deal with gold, silver and copper operations, mainly of the manual kind without the environmental threats offered today. The hardrock mining industry remained exempt from reporting toxic chemical releases until 1998, when a Toxic Release Inventory, named them as the largest releasers of toxic chemicals in the nation, even more so than the electrical industry, having dumped nearly 3.5 billion tons of toxic pollutants, the preceding year.
Hey I am doing a project for a class and I need to justify mining in South America, the Canadian/Brazilian study about the Tapajos would be very helpful but I have been unable to find it. Can you post it please?