What Is AMD?
AMD comes from the oxidation of sulphide minerals. It has the negative impact on the environment. Since it could affect the surface water, ground water quality and land used. This condition due to the low pH contains by the water (could reach up to 2), sulphate content (SO4), and metals content (Fe, Zn, Cu, Ni, As, Cd).
The principles for AMD formation should be understood to be able to manage the water.
i. Waste containing reactive sulphide (S2-, S22-) ii. Elemental sulphur (S0) and others sulphur intermediates (Thiosalt, S2O3¬) iii. Molecular oxygen iv. water
Furthermore, the rate of AMD generation is known by the following factors: • bacterial activity
• the presence of …show more content…
AMD control measures and prevention
The aim of process is to eliminate the sulphide oxidation by air or water control method, control of water migration, separation and blending waste with the alkaline material, dry and water cover etc.
Acid Mine Drainage Prevention
1. Surface water dispersion
The purpose of this action is minimizing water in contact with the potential acid material. The method is easy to apply but need to be careful in diverting the water.
2. Soil compaction
The purpose of this step is to reduce the soil permeability. It means reducing the hydraulic conductivity and diffusion of oxygen. This action will reduce the water penetrate the tailing and sulfide metal oxidation.
3. Dry covers
The purpose of this method is to prevent oxygen and water penetration. According to (Pozo-Antonio, et al., 2014) dry covers are used for:
• Mining waste stabilization to prevent erosion by wind and water
• Aesthetic appearance improvement
• Both prevention and inhibition of pollutant …show more content…
7. Sealing with clay
When AMD is produced through ground water discharge, sealing the area with clay material could reduce the impact to the nearby environment. In case the water flow to the lake then it would harm its ecosystem.
8. Handling tailing
The order of stacking material can influence the acidity of the tailing. Placing sulfides to maximum contact with the surrounded are can produce maximum acidity compare to carbonate rock.
The purpose of the action is to prevent the conversion of ferrous to ferric iron by using anionic surfactants. Bactericides can be sprayed by hydro seeder but this method is not for long term solution. It helps to prevent acid environment in the pyritic rock which opens until the site reclaimed. This method works best by combining with other prevention methods. (G. Skousen, et al., 2000)
Isolating the AMD potential material can be done by trapping it below water proof trap such as clay or plastic. Compacting the material will help to improve the condition of tailling by reducing