Friday, April 30, 2010

Acid Mine Drainage

by Jodi Wallace

As we all know, mining can create a variety of serious environmental degradation issues. The one I want to discuss is called acid mine drainage (AMD). The science behind AMD is actually pretty in-depth and there are still a lot of ongoing studies regarding its cause and treatment, but basically, AMD occurs when sulfur-bearing minerals are exposed to water and air, allowing for the formation of sulfuric acid. Heavy metals leached from the rocks can combine with the acid and dissolve, creating highly toxic runoff. While small amounts of this runoff can occur naturally, mining (both strip and subsurface) exposes more minerals to more air and water and therefore produces sulfuric acid runoff at a much higher rate when compared to the natural rate of discharge. The process of AMD can result from both new mines as well as mines that have been abandoned for over 100 years. The environmental impact of AMD is enormous when this runoff drains into nearby rivers and streams (EPA). According to the EPA, there are about 500,000 abandoned mines in the U.S. and about 40% of the U.S. western watersheds are polluted with metals from these mines. Altogether, the cost of cleaning up these abandoned mines is estimated to cost about $30 billion dollars, and some call it today’s greatest environmental issue. Waters polluted from AMD can harm the aquatic life in the rivers, our drinking water, outdoor recreation, and can also lead to corroding wastewater pipes and other infrastructure (Limerick, et. al).

There are two major issues with AMD clean up. The first is a lack of enforcement in current mining operations, and the second (oddly enough) is the Clean Water Act.

Let’s start with enforcement. The only true, cost-effective way to solve AMD is to prevent it from occurring in the first place. The best regulation in place to prevent this sort of environmental degradation – and save taxpayers millions and billions of dollars in water treatment – is SMCRA (the Surface Mining and Reclamation Act of 1977). SMCRA basically assigns stringent standards to mining operators and makes them accountable for the environmental degradation they inflict, including water pollution. However, SMCRA isn’t always enforced; anyone can drive up I-70 and see the effects mining has had in the Rocky Mountains. SMCRA is most obviously ignored in the Appalachian region, where Mountain Top Removal (MTR) is particularly destructive and harmful to the environment, as well as to the local communities. MTR companies are incredibly behind in their reclamation efforts - most haven’t even tried to reclaim the land they’ve destroyed - and they owe millions (possibly billions) of dollars, but have no incentive to pay so long as the OSM continues to fail to enforce the regulations.

AMD is most difficult to treat in abandoned mines, not only because a number of historic mines in the western states are not mapped, but also because there are no parties to hold responsible for the cleanup. The Clean Water Act (CWA), while beneficial for nearly every other water pollutant, actually makes AMD clean up more difficult. An organization that tries to treat a mine for AMD effectively becomes permanently responsible for the mine under the CWA. This means that anyone – nonprofit, government agency, local community, corporation, etc. - that tries to treat a mine also becomes responsible for any damage or pollution the mine has created or will create in the future. The organization, by taking liability, must ensure that the water quality meets the standards required by the CWA, which, in the case of AMD, can be extremely costly and may require continued treatment for decades. Simply put, the people who want to clean up the damage either have to clean it up completely or not at all; there’s no variability in the CWA that allows for a partial clean-up effort.


  1. This comment has been removed by the author.

  2. here was my source, by the way, if anyone happens to want to read more about it...

  3. Acid mine runoff is definitely a huge problem that goes largely ignored. I agree that enforcement of clean up laws is by far one of the biggest problem facing acid mine runoff. However I think that much of the mines that remain uncleaned are older mines which in many cases the company that ran them is no longer around. Because of this I think we need to add a new government organization that specializes specifically on mine clean up. This task force could not only clean up mines but keep track of current mines and make sure they follow proper cleanup procedures.


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