The most effective method to remediate acid mine drainage AMD in a mine site and improve the quality of water impacted by this phenomenon is a combination of passive and active treatment systems. These methods aim to neutralize the acidity, remove heavy metals, and restore the water quality to acceptable levels. Some of the most effective methods include:1. Limestone neutralization: Limestone is used to neutralize the acidic water by increasing the pH and precipitating heavy metals. This can be done through the construction of limestone channels, limestone ponds, or adding crushed limestone directly to the affected water.2. Constructed wetlands: Constructed wetlands are engineered systems that use natural processes involving wetland vegetation, soils, and associated microbial communities to treat AMD. They help in the removal of heavy metals and neutralization of acidity through processes such as precipitation, adsorption, and microbial activities.3. Anoxic limestone drains ALD : ALDs are buried trenches filled with limestone that intercept the AMD and promote the dissolution of limestone, which neutralizes the acidity and removes heavy metals through precipitation.4. Active treatment systems: These systems involve the use of chemicals, such as lime or caustic soda, to neutralize the acidity and precipitate heavy metals. Active treatment systems require regular maintenance and monitoring but can be highly effective in treating AMD.5. Bioremediation: This method uses microorganisms, such as bacteria and fungi, to break down contaminants and reduce the acidity of the water. Bioremediation can be applied in situ in the mine or ex situ in a treatment facility .6. Permeable reactive barriers PRB : PRBs are underground barriers made of reactive materials, such as zero-valent iron or limestone, that intercept and treat AMD as it flows through the barrier. The contaminants are removed through processes such as precipitation, adsorption, and reduction.7. Diversion and containment: This method involves diverting clean water away from the mine site and containing the AMD to prevent it from contaminating nearby water sources. This can be done through the construction of diversion channels, dikes, or impoundments.The selection of the most appropriate method s depends on the specific conditions of the mine site, such as the volume and chemistry of the AMD, the available resources, and the desired level of water quality improvement. In many cases, a combination of these methods is used to achieve the best results.