A study of the mineralogical, hydrological and biogeochemical controls on drainage from waste rock at the Antamina Mine, Peru : an overview

A multi-scale study of solute release, transport, and attenuation mechanisms in waste rock under neutral drainage conditions is underway at the open-pit Cu-Zn-Mo Antamina mine in the Peruvian Andes. The objectives of the project are to better understand the mechanisms that control the fate of elements of concern, principally Zn, Mo, Cu, and As, and to develop field- and laboratory-derived scale-up relationships that provide a framework for prediction of waste-rock drainage quality at field scales and over long times. Five 36 m x 36 m x 11 m high instrumented experimental waste-rock piles have been constructed on site to provide insight into the hydrological and geochemical behavior of distinct combinations of waste rock under field conditions. Field cells constructed from 60 L barrels provide data on leaching behavior of the distinct rock types. Our results allow us to constrain the water balance, demonstrate that mixing of distinct waste-rock types may enhance attenuation of Zn and Mo in drainage and suggest that sulfide mineral oxidation may become O₂-limited in fine-grained reactive material.[All papers were considered for technical and language appropriateness by the organizing committee.]