Abstract

In order to characterize weathering of chalcopyrite and behavior of dissolved metal ions in waste rocks from Manjang Cu mine, Mineralogical studies such as refractive microscope, XRD and SEM/EDS anlayses carried out. The weathering was mainly occurred in fractures and edge of the chalcopyrite within the mine waste rocks. The weathering process can be seen to reflect four stages based on the weathering degree of chalcopyrite. The main secondary minerals are goethite, covellite, aazurite, malachite and brochantite. Dissolved Cu and As were mainly absorbed Fe-hydroxide. Poorly crystalline Fe-oxide contains relatively high as contents. In oxdizing condition, the weathering of chalcopyrite mainly occurs along the fracture, while the replacement of chalcopyrite observed mainly in the grain and produced covellite and brochantite. The dissolved metals (Cu, Fe, As) in waste rocks from the abandoned Manjang mine area could attenuate naturally by precipitation, adsorption and replacement reaction.

Keywords chalcopyrite, secondary mineral, adsorption, precipitation, replacement