At the recent Latin American Congress of Environmental Sciences of the Faculty of Sciences of the University of Bío Bío, in Concepción, the SMI-ICE-Chile researcher presented the results of a study to prevent acid mine drainage, one of the greatest environmental and economic challenges facing the mining industry.
This international meeting brought together the scientific community, professionals, representatives from the public and private sectors, social organizations, and students to share knowledge and technological solutions in the fields of environmental sciences, chemistry, and applied physics.
At this event, Dilan Campos presented on «Acidification of copper sulfide tailings: Neutralization chemistry, geochemical controls, and trace metal release.» This work is the result of research and development by a team that also includes Marcela Calderón, David Rubinos, and Jacques Wiertz, from SMI-ICE-Chile; Tamara Ortiz P and Sofia Leonor Paredes Guerra, from the Universidad del Desarrollo; Javiera Gerding and Oscar Jerez, from the Universidad de Concepción; and Almendra Nieto Torres, a student of Civil Engineering in Biotechnology at the Universidad de Chile.
Dilan Campos explained that acid mine drainage (AMD), generated in the tailings of mining operations, is one of the greatest environmental and economic challenges facing the mining industry globally. The main cause of this problem is an iron-sulfur mineral called pyrite, which, when in contact with water and oxygen—and sometimes bacteria—oxidizes and produces this acid drainage that contaminates surface and groundwater, seriously endangering crops, flora, fauna, and also human health.
Dilan Campos presented the results—with details of their physical and chemical implications—of a methodology that seeks to understand acid neutralization behavior, the mechanisms involved, and the tailings components that act as geochemical controls of the process, with the goal of evaluating and predicting the release of metals into the environment in response to a decrease in pH. «The proposed methodology proves to be effective in identifying geochemical controls and predictively and realistically assessing the release of metal(oid)s in AMD-generating tailings,» he explained.
These results are part of the research being conducted by SMI-ICE-Chile, which seeks to develop a passivation technology to prevent this serious problem. To date, the results indicate that the laboratory-scale passivation technology has promising performance in terms of its ability to microencapsulate pyrite and increase the pH of acid leachates, opening up the potential for long-term risk and cost reduction.
«These are preliminary but encouraging results,» notes Dilan Campos. «The next steps are to scale up this work with field testing and validation to evaluate the stability of the sulfide coatings in the face of environmental changes.»
This research is part of a project under Corfo’s Crea y Valida Program to promote innovation. It also has support from the Center for Research in Technologies for Society (C+) of the Faculty of Engineering of the University of Concepción and the Institute of Applied Economic Geology of the University of Concepción.
