Originally Posted by
positron
The article seems to be only concerned with acid drainage and, I believe, is completely wrong about the levels of acid. Battery acid is around 30% sulfuric acid by weight (70% water). For a mine to produce acid concentrations of that amount, it would have to make unbelievable amounts of acid per minute for even a trickle of water from the mine. If, for example, the mine leaked out 10 gallons of water a minute, it would have to produce 43 pounds of sulfuric acid each and every minute to reach those levels. You might be able to produce that amount of sulfuric acid in an industrial process but natural weathering of rock just can do it. 30% sulfuric acid would be highly toxic too.
The acid in acid mine drainage is the least of the problem. The acid mobilizes heavy metals by dissolving and reacting with them. At 30% sulfuric acid concentrations produced at the amounts of water flow these mines can discharge, it would eat a mountain down to stubs in a matter of days.
Don't get me wrong, mine acid drainage is a problem but it's not as big a problem as the article suggests. Certainly not 1000 times as concentrated as battery acid.