According to Partha Das Sharma there are two types of treatment for acid mind water and drainage. These are active and passive processes. The active process is chemically based. The idea is to add chemicals to increase the Ph levels therefore causing the acid solubles to form insoluble complexes and precipitate. This technique is expensive and usually depends on the acidity the flow rate and the predicted outcome of the water. Limestone is most commonly used. The passive treatment is a more biological process, which takes time and is also expensive. This is more of a natural process. There are six different methods; Aerobic wetlands, Anaerobic wetlands, Alkalinity producing systems, Anoxic limestone dams, Limestone ponds and open limestone channels. (Acid Mine Drainage and its control. Partha Das Sharma).