How do you mitigate 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.
Can acid mine drainage be remediated?
Acid mine drainage (AMD) remediation can be complicated due to its composition, many researchers have used various techniques such as chemical precipitation, solvent extraction, micellar ultrafiltration, organic and inorganic ion exchange and adsorption (Hobbs et al., 2001, De Marco et al., 2003).
What is responsible for 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.
Is AMD and ARD the same?
Nomenclature. Historically, the acidic discharges from active or abandoned mines were called acid mine drainage, or AMD. The term acid rock drainage, or ARD, was introduced in the 1980s and 1990s to indicate that acidic drainage can originate from sources other than mines.
How long will Acid Mine Drainage continue?
It is not unusual for surface or underground mines to continue to yield AMD for many years or decades after mining has ceased. Legacy mining in the Appalachian Coal Region has numerous mines that continue to yield AMD more than 100 years after closure.
How long does it take to clean acid mine drainage?
For wetlands to remove metals, the mine water needs to be held for 20 to 40 hours (Cohen 1996). If the mine water pH is below 5, the residence time should be 40 hours.
How can AMD be remediated?
Anaerobic sulfate-reducing bioreactors are another type of widely used passive treatment technology, which involves sulfate-reducing bacteria to remediate AMD. Sulfate-reducing bacteria use the energy produced in this reaction for their growth and development.
What causes acid rock drainage?
Acid mine drainage (AMD) is the runoff produced when water comes in contact with exposed rocks containing sulfur-bearing minerals that react with water and air to form sulfuric acid and dissolved iron. This acidic run-off dissolves heavy metals including copper, lead, and mercury which pollute ground and surface water.
How long will acid mine drainage continue?
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.
What does acid mine drainage smell like?
Pyrite goes through a series of reactions when it is exposed to the environment, which can occur when land is disturbed. When exposed to oxygen and water, pyrite forms yellow and white salts of iron sulfate and sulfuric acid. Another way to tell if a stream is impacted by AMD is if the water has a rotten egg smell.
What is the threat of AMD?
Acid mine drainage (AMD) has become one of South Africa’s largest environmental threats, as AMD has caused considerable damage to the natural environment and communities living near mining areas, says engineering consultants WSP Africa’s hydrology, environment and energy senior associate Karen King.
