Question

Where in the US is AMD an issue? What treatment technologies can be used to remediate sites which have been impaired by AMD? Have any of these technologies been used in Pennsylvania? How can AMD be prevented?

Answer 1

Where in the US is AMD an issue?

Kensington Mine in Southeast Alaska

Mining near the Iron Mountain Mine

Argo Tunnel, Idaho Springs, Colorado, USA

Berkeley Pit superfund site

The Summitville Mine in Rio Grande County, Colorado.

Clinch-Powell River system, Virginia and Tennessee, USA

Cheat River Watershed, West Virginia, USA

Copperas Brook Watershed

Davis Pyrite Mine in NW Massachusetts

Hughes bore hole, Pennsylvania

Gold King Mine, Colorado, USA

Treatment technologies: Various chemical neutralisation processes are adapted to impair the areas affected by AMD.

• Lime neutralisation: This involves addition of lime which deposits as gypsum and reduces the acidity
• Calcium silicate neutralisation where calcium silicate with H+ ions to bring down acidity
• Ion exchanges membranes ar being developed which also can potentially reduce the quantity of H+ ions

The above mentioned methods have been used in Hughes bore hole, Pennsylvania and Old Forge borehole, Lackawanna River.

AMD prevention:

• Providing fresh water supply to mines which can remove the oxygen that can aid AMD production
• Avoiding water from mines to pass through metals on the mine site
• Redirecting the water to underground to avoid exposure of oxygen
• Maintaining high bacteria control in the water by taking preventive measures