Role of redox-reactive minerals in the reuse and remediation of mine wastes

Abstract

Mining, oil and gas and other extractive industries are vital and irreplaceable constituents of the modern global economy. The overall demand for the products of these industries rises inexorably with economic growth and developing prosperity. However, these industries produce vast quantities of potentially harmful waste. Many of the elemental, and hence mineralogical, components of the waste stream are redox active. This review focuses on redox-reactive minerals sourced from this waste stream in reuse and remediation schemes. Copper-, manganese- and iron-bearing mine wastes are used as pigments, in fertilizers, sorbents of toxic compounds in water treatment systems, and for the production of SO 2 and H 2 SO 4 . Some solid mine wastes can be remediated by phytostabilization, where plants are used to induce the precipitation of secondary redoxreactive minerals that sequester contaminants. Liquid wastes are remediated using a variety of abiotic and biotically-assisted schemes such as anoxic limestone drainages and permeable reactive barriers. These schemes use phases such as zero-valent iron and Feoxyhydroxides, and produce mineralogical by-products such as sulfides, green rust and oxyhydroxides. Further research is needed to optimize the reuse and remediation schemes in mine wastes and to develop new and innovative systems employing redox active minerals.