What is the chemical reaction to form acid mine drainage?
Mine drainage is formed when pyrite (an iron sulfide) is exposed and reacts with air and water to form sulfuric acid and dissolved iron. Some or all of this iron can precipitate to form the red, orange, or yellow sediments in the bottom of streams containing mine drainage.
How does acid mine drainage have a negative impact on the environment?
The low pH value of the discharge mine water results in the further dissolution of minerals and release of toxic metals, when it allowed getting discharge into other water bodies. This acidity and high toxic metals concentration are harmful to the vegetation, aquatic life and wild life.
Does mining cause acid drainage?
Metal mines may generate highly acidic discharges where the ore is a sulfide mineral or is associated with pyrite. The most commonly mined ore of copper, chalcopyrite, is itself a copper-iron-sulfide and occurs with a range of other sulfides. Thus, copper mines are often major culprits of acid mine drainage.
What does acid mine drainage look like?
Acid drainage is often marked by “yellow boy,” an orange-yellow substance (visible in the photo on this page) that occurs when the pH of acidic mine-influenced water raises above pH 3 (approaching more neutral conditions), so that the previously dissolved iron precipitates out.
How does acid mine drainage affect groundwater?
During mining, ground water is drained from the rocks and the pyrite associated with the coal beds is exposed to air. The acid mine drainage adversely affects the ground-water quality by increasing the iron and sulfate content of the water especially in the vicinity of the strip mines.
What effect can acid mine drainage have on buildings?
The acidic water increases the solubility of aluminium and heavy metals which may be present in the affected region. The overall effect is to render the water toxic to varying degrees.
What is the threat of acid mine drainage?
Acid drainage polluted stream merges with unpolluted stream downstream from California’s Jamestown mine. Acid mine drainage is one of mining’s most serious threats to water. A mine draining acid can devastate rivers, streams, and aquatic life for hundreds, and under the “right” conditions, thousands of years.
How long will Acid Mine Drainage continue?
Acid mine drainage and metal leaching are a particular concern because they can continue indefinitely, causing environmental damage long after the mine operation has ended. 2 Acid mine drainage still occurs from hard-rock mines in Europe that were worked by ancient Romans prior to A.D. 476.
Does Acid Mine Drainage increase pH?
Acid mine drainage (AMD) is a major water quality problem as it reduces the pH of water resource, making dissolved metals readily available for uptake by benthic organisms and fish, which becomes a major pathway of their introduction into the human food chain.
How does acid mine drainage affect pH?
How does acid mine drainage affect humans?
2 Page 2 The first major issue that comes from mine drainage is that it contaminates drinking water. Once acid flows into streams humans cannot consume the water even after filtration. The corroding affects from the sulfuric acid in the water eat up parts of infrastructure like bridges, dams, wells, and even docks.
Where is acid mine drainage in South Africa?
The Witwatersrand is not the only region in South Africa where acid mine drainage is a problem, but it is currently the area of greatest concern. In 2002, near the town of Krugersdorp, acid mine drainage from an abandoned mine welled up and began pouring out on the surface.
Who is the Committee on acid mine drainage?
McCarthy is a member of the technical task force appointed by the committee on acid mine drainage to investigate the problem and suggest solutions. A bigger problem than the acid mine drainage from the tailings piles at the surface, however, is the acid filling the underground mines.
Where are the tailings dumps in the Goldfields?
In the Witwatersrand goldfields, 30 kilometers south of the caves, more than a century of mining has left the region littered with mounds of waste, known as tailings dumps, and underlain by a deep underground network of abandoned mine shafts, which are gradually filling with water.
What kind of rock is in the mining district?
The metamorphic rock of the mining district contains abundant pyrite (iron disulfide or “fool’s gold”), which reacts with oxygenated rainwater or groundwater.