Acid Mine Drainage

By: Nicole Liguori Melissa Pskowski

What is Acid Mine Drainage?

• AMD is damage done to aquatic / terrestrial ecosystems because of

highly acidic, metal-laden discharges from abandoned mines.

What Causes it?

Acid mine drainage was caused by mining for rich coals and metals. During the 19th

and early 20th century large amounts of coal and other metals were extracted from the earth through different kinds of mining.

Once they were done they abandoned the site. In a nutshell the mine was left to fill

with water, which reacts with oxygen thus forming iron, sulfate and sulfuric acid. The

sulfuric acid is what causes its high acidity.

A Little Chemistry

• The average pH level of the acid mine drainage is 2-4. Being that this is so low, it

indicates that it is highly acidic. In comparison, vinegar has a pH of 4.7, and

acid rain in sometimes in the range of 4-5.

Where is it?

• 95% of acid mine drainage occurs in western PA, West Virginia, South West Virginia and parts of Maryland. This is due to its proximity to the Appalachian Mountains and the

coal mining that took place in these areas.

Effects

• Untreated acid mine drainage seriously hurts habitat and water quality. Thus killing most aquatic life and makes the environment unsuitable for organisms to thrive. It is also a

problem because it can damage water quality that its citizens use such as drinking water. This problem occurs the

most in PA. In 1995 PA failed EPA water quality tests because of 2425 miles of contaminated streams.

Treatments

• The most widely used treatment for acid mine drainage is by adding acid-neutralizing chemicals. This is known as active treatment. Some of these

chemicals are lime, anhydrous ammonia, and sodium hydroxide.

Treatments Cont…

• Another type of treatment is passive treatment where the drainage water is held in oxidation ponds where a thick sludge will form on the

bottom. It is then treated and later discharged into streams. Thus the water is neutralized

forming a wetland or a pond.

Downsides of treatment

• Water that is discharged into streams can still remain slightly acidic and toxic. Secondly the sludge that forms on the bottom of the pond can get pumped back into the pond.

Works Cited • “Chemical Treatment.(acid mine drainage)(brief article).” World and l. 19. 2 (Feb

2004): NA. Student resource center-gold. Gale. Stroudburg High School. 26 Feb. 2009. www.galegroup.com.

• “Acid mine drainage.” DISCovering Science. Online ed. Detroit: Gale, 2003. Student Resource Center-Gold. Gale. Stroudsburg High School. 26 Feb. 2009 www.galegroup.com.

• “Acid Mine Drainage”. www.wikipedia.com feb 14 2009

• The End