use of toxic chemicals
copper: sulfuric acid is used for leaching of copper from oxide ore, and some sulfide ores. the leaching solution is claimed to be diluted and recycled. however, it is recycled into lined ponds of high toxic levels of sulfuric acid. the sulfuric acid can enter the soil and groundwater through breaks, spills, tears in liners.
for a report on the impact of sulfuric acid leaching
gold: cyanide is used for leaching gold. this leaching has been banned in montana, thanks to the heroic efforts of montana environmental information center who led a twice-won, citizen- initiated law banning cyanide heap-leach mining in montana. the law has been upheld in the district, federal, and state supreme courts despite canyon resources (mining), inc.’s efforts to repeal it in order to develop a massive open-pit, cyanide leach gold mine less than 800 feet from the blackfoot river headwaters.
initiative 137 was a response to the abysmal track record of open pit cyanide leach mining in montana, as exemplified by cleanup fiascos at the golden sunlight, zortman/landusky, and kendall m ines and the montana department of environmental quality's failure to adequately regulate such m ines as required by state law.
toxic chemicals are used in the flotation process to separate the copper and molybdenum out of the milled powder. this flotation process is the major extraction method at duval/sierrita mine because of the poor quality of the copper at this site. some chemicals produce bubbles that that the copper adheres to and the "bad stuff" falls to the bottom. these chemicals are hydrocarbons with complex configurations, but some are as simple as kerosene. it is claimed that the volatile organics used in the flotation process do not go into the slurry that goes into the tailings impoundment because they are filtered out before the slurry goes to the impoundment. this is not a sound analysis.
1) filtration is not a treatment technology for volatile organics. treatment is pushing air the solution which releases the volatile chemicals into the air [bless the employess who endure this process—it would definitely fall under osha regulations].
2) some are amine compounds that break down into nitrates, so the presence of nitrates in the groundwater is an indicator of travel of these compounds, which can be very mobile in an oxygen solution (h 2o).
some of the chemicals used in flotation process
- alky aryl oxime
- petroleum distillate
- sulfosuccinate surfactant
- alkyl xanthate salt
- nalco 7873—no chemical formula given
- alcohol/hydrocarbon blend
super powerful explosives—anfo (ammonium nitrate and fuel oil)—used to blast the rock in the pit leaves traces of nitrates in the blasted rock and the flotation solution.
a complete, scientific explanation of the process of making copper
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