Research Projects

Project Summary : 1. Project Title: Investigations towards Mitigation of the Problem Of Acid Mine Drainage In India 2. Rationale: Acid Mine Drainage (AMD) is a problem affecting mine environment leading to widespread water contamination. It occurs in metal mines and coal mines containing pyrite ores. The pyrite under the action of oxygen and bacteria, gets converted into acid which lowers the pH of the water. The acidic discharge containing high sulfate, hydronium ions (iron in case of iron pyrite) further leaches out heavy metals and anions present in the strata causing extensive destruction. Apart from making the water undrinkable and highly toxic, AMD also leads to heavy damage to mining machinery on account of corrosion. The problem becomes so acute that often it leads to premature mine closure. In India the problem of AMD in coal mines is concentrated in the high pyrite ore bearing coalfields of the North- East and lignite mines of Western and Southern India. In the North-east it has rendered streams and even some river stretches toxic and unusable. So far isolated studies were undertaken to solve the problem. However, to the best of our knowledge no studies focused on understanding the magnitude, contaminant source evaluation, on a national level by detailed characterization and analysis of AMD water samples collected from different coal mines. There is also no research work that has centred on development of a broad spectrum treatment technology for AMD mitigation which can be used in different sites with minor customizations. T 3. Hypothesis /model to be tested i) Stagewise precipitation:. ii) In-situ permeable barrier: iii) Cross flow NF : 4. Main experiments carried out: Scope of the work Work component 1: i) Detailed physicochemical characterization of AMD water samples in terms of major ions, heavy metals, trace elements, TDS, TSS, EC, pH, ii) Characterisation of the sludge with respect to morphology, mineralogy, elemental composition iii) Contaminant source evaluation iv) Major ion chemistry and principal component analysis Work component 2: i) Stagewise precipitation with cost-effective chemical dosing ii) Membrane separation iii) Recovery of value added products from the concentrates and sludge such as ettringite formation iv) Sludge passivation v) Experimentation towards development of permeable reaction barriers 5. Significance of the proposed work i) The fundamental understanding of the contaminant matrix of AMD will provide critical insights into the wider picture of the problem of AMD in India ii) The broad spectrum technique will take into account the different contaminant matrices and will focus on their removal on individual or collective basis. The same can be applied to different AMD water treatment from coal mines with minor customization. iii) Viable active treatment will not only remediate the AMD water but will also prevent its spread