In light of the Gold King Mine incident this month, concern is being raised over the environmental risks associated with the numerous abandoned mine sites around the country. Abandoned Mine Lands, or AMLs, can present a serious problem for the environment and human health. The Bureau of Land Management estimates there are as much as 500,000 AMLs nationwide – many of which have not been assessed to determine their potential threat and impact.
The act of mining produces fine and large grain waste products, which contain a variety of different elements from radioactive material (in the case of mining uranium) to heavy metals, lead and arsenic. As a result of these elements, highly acidic, corrosive water can form in mines – which pose a risk to both surface and ground water supply.  When gold mining became prevalent over 150 years ago, little was done by mine owners to prevent pollution and/or remediate lands once abandoned. Mine closure planning is relatively new to the industry and has evolved significantly since it was first developed.
According to the Abandoned Mine Lands Portal, less than 40,000 of the potential 500,000 AML sites are in the Bureau of Land Management database.  Most of the known sites have not been assessed and it is extremely difficult to estimate how long it would take or the true cost of remediation. Bloomberg News estimates that cleaning up abandoned mines could potentially cost as much as of $54 billion.
Recently, the Denver Post reported that almost half of headwaters in the West are polluted by toxic runoff from old mines; and, at least 230 mines are releasing the equivalent of one Gold-King-size discharge every two days in Colorado. According to the Bureau of Land Management, addressing Abandoned Mine Lands (AMLs) is becoming extremely important due to increased exposure to people and risks of accidents or injuries. As we consider the difficulty in cleaning up the Animas River it is important to take note of how past actions impacts future generations.
- Extent of Problem
- What Happens to Mine Sites After a Mine is Closed?
- Abandoned Mine Lands
- The Silver Lining of the Gold King Mine Spill
 (no author) Abandoned Mine Lands, U.S. Department of the Interior Bureau of Land Management
 (no author), The Silver Lining of the Gold King Mine Spill, BloombergView