What are the causes of acid mine drainage?

Acid mine drainage is the formation and movement of highly acidic water rich in heavy metals. This acidic water forms through the chemical reaction of surface water (rainwater, snowmelt, pond water) and shallow subsurface water with rocks that contain sulfur-bearing minerals, resulting in sulfuric acid.

What causes acid mine drainage in South Africa?

Acid mine drainage (also sometimes referred to as acid rock drainage) is a well-understood process2 and arises primarily when the mineral pyrite (‘fool’s gold’ or iron disulphide) comes into contact with oxygenated water.

What are the effects of acid mine drainage on the environment?

The most immediate and serious impacts of acid mine drainage are on natural waterways. High levels of dissolved metals may kill off all of the resident fish and aquatic life. Migratory creatures not resident to mining sites are also affected.

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 can we prevent acid mine drainage?

The most prevalent method for treating AMD contamination is the addition of alkaline reagents such as lime, limestone, sodium carbonate or sodium hydroxide. This treatment aims at neutralizing acidic water and the precipitation of heavy metals.

How do you fix acid mine drainage?

Some common methods include: Reclamation of contaminated land by (1) adding lime or other alkaline materials to neutralize the acidity, and (2) adding uncontaminated top soil, planting vegetation, and modifying slopes to stabilize the soil and reduce infiltration of surface water into underlying contaminated material.

Why is AMD such a problem when a mine closes?

AMD is a significant and costly environmental challenge facing the mining industry worldwide. The lack of knowledge or uncertainty as to the effectiveness of the waste management strategies being used has left mine owners and the State facing significant long term complications.

How do you stop acid mine drainage?

What are the benefits of acid mine drainage?

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.

What happens to water which contains acid mine drainage?

Some or all of this iron can precipitate to form the red, orange, or yellow sediments in the bottom of streams containing mine drainage. The acid runoff further dissolves heavy metals such as copper, lead, and mercury into groundwater or surface water.

What causes acid mine drainage?

In a nutshell, acid mine drainage is a form of water pollution that happens when rain, runoff, or streams come in contact with rock that is rich in sulfur. As a result, the water becomes very acidic and damages downstream aquatic ecosystems.

What is the definition of acid – mine drainage?

From Wikipedia. Acid mine drainage ( AMD ), or acid rock drainage (ARD), refers to the outflow of acidic water from (usually abandoned) metal mines or coal mines.

What is acid drainage?

Definition of Acid drainage. Acid drainage means water with a pH of less than 6.0 and in which total acidity exceeds total alkalinity, discharged from an active, inactive, or abandoned surface coal mining and reclamation operation or from an area affected by surface coal mining and reclamation operations. Sample 1. Sample 2.