Mining Contamination in the Rocky Mountains

By Kaley Williams

Mining

AMD (Acid Mine Drainage) Definition and Importance

Case Study- Summitville CO

Ouray Colorado, A small mining community since the 1800s.

Importance of Mining Contamination

Mining contaminating watersheds has become one of the largest pollutants of water in the WestPollution can continue to flow into bodies of water long after the mining endsThe metals have severe environmental effects degrading water quality and aquatic habitat

Yellow Boy Precipitation in a mountain stream, San Juan Mountains, Colorado.

PollutionAcid Mine Drainage (AMD) is metal-rich water that is formed from the oxidation of pyrite (FeS2) with air and water. Mineral pollutants in the water of iron, zinc, aluminum, manganese, cobalt, nickel, copper, arsenic, cadmium, and lead. AMD makes water highly acidic and ends up having a high concentration of dissolved heavy metals. The precipitate from the iron forms red, orange, and yellow sediments in the surrounding areas. The United States Environmental Protection Agency (EPA) has singled out AMD as the number one quality problem

This precipitate is also called "yellow boy".   It is an unsightly, slimy, yellow or orange colored solid that coats the stream bed and discolors the water.  "Yellow boy" also has a negative impact on all living organisms in the stream.

Summitville and its History

Gold was first discovered in Summitville in 1870. The Summitville mine went into production in 1980s using a new technique for extracting low grade ores. Cyanide heap leaching is a process used to extract gold by crushing the rock and sprinkling it with cyanide to leach out the precious metals.Located at 11,500 ft in the San Juan Mountains in the Southwest part of Colorado, the site covered 1,400 acres of federally owned land. This process accounts for 35% of domestic gold production and has made the US the second ranked producer in the world.

1986

1989

1992

1994

2000 +

Summitville’s TimelineEmergency

“pumpback” system was installed to

recycle contaminated solution back to leach

pad

A process solution treatment was installed to

clear up the discharge

December, SCMCI declared bankruptcy and abandoned the mine site leaving a mess of more than

$120 million to clean up for the EPA

The EPA had placed the Summitville mine site on the National Priorities List as a Superfund toxic

cleanup site. The EPA was spending $53,000 a day to

clean up the worst parts of the

contamination

The Alamosa River begins showing signs of life. Already,

tax payers have spent over $128 million on cleaning up the

area, and the total long term clean up is determined to go

on for at least another decade spending $3 million a year

Terrace Reservoir

Headwaters of the Alamosa River. A natural acidic iron

spring.

Tying It All Together

Mining can drastically impact its environment and the surrounding ecosystems. AMD contaminates water sources degrading the quality of water that affects both humans and plant and animal habitats. Summitville, CO is one example out of thousands that exemplify the affects of mining and the forms of pollution that are dealt with on a daily basses. There are many different techniques to cleaning up mining pollution, but they are expensive and become long term projects. With recent developments in the government and public awareness of the problems associated with mining, technology is improving for cleaning up the water systems as well as preventing future contamination.