Despite decades of research into less-toxic alternatives, cyanide remains the best chemical for separating gold from low-grade ore, so it'll be around a while.
The biggest problem with cyanide isn't that it's toxic. The real issue is that it allows mining of vast amounts of rock, Miller says.
ACID DRAINAGE
Thanks to high gold prices, it's worthwhile to mine ore that has just $6 or $8 of gold in each ton.
The result? Pile upon pile of waste rock that hasn't seen oxygen or water for millions of years. Freed from the ground, that rock oxidizes and generates sulfuric acid, a corrosive liquid that can burn plants, birds and animals.
"It's very difficult to stop. You get some serious problems that need to be remediated," Miller says.
Other potential contaminants include mercury and arsenic
No comments:
Post a Comment