Acid Drainage Prevention – Microencapsulation Technology
Interview with Felipe Saavedra
Acid mine drainage (AMD) is something the global mining industry must face. The challenges that it presents regarding environmental and water resource sustainability have yet to be resolved and must be handled today, looking toward a sustainable mining future. The Centre of Excellence in Chile from the Sustainable Minerals Institute, University of Queensland (SMI-ICE-Chile) is working on a pilot project to prevent acid mine drainage through particle microencapsulation technology.
SMI-ICE-Chile’s mission is to develop innovative research and technologies to solve the challenges faced by the mining sector. This project, co-financed by Fundación Copec-UC, is very important for the Centre since it will allow to continue the development of AMD preventive technology, which could have impacts on the entire industry. Felipe Saavedra, project lead and researcher at SMI-ICE-Chile answers some questions about the project.
What is AMD and what generates it?
In the current scenario, one of the primary environmental problems is AMD generated from mine sites (abandoned, closed and active), which are characterized by a low pH, elevated concentrations of metals/metalloids and sulphate in solution. Their high reactivity, complexity of the chemical composition, and toxicity make AMD into one of the worse environmental issues today.
What does the microencapsulation technology project entail?
This project emerges from my PhD thesis at the Univ. of Queensland where I wanted to improve the geochemical stability of lead and zinc tailings. This project continues with the development of microencapsulation technology to prevents the generation of acid mine drainage. This is achieved by using a low-cost chemical solution, which can be applied in tailings sands and fines; waste rock dumps and leach pads; mine walls and tunnels with the potential of generating AMD. For the next stage of the project, we are looking for a mining company partner to carry out pilot testing in a real environment.
What is the expectation regarding its impact to the industry?
It is estimated that the adoption of microencapsulation technology by the mining industry could dramatically decrease economic costs associated with current AMD treatment measures during operation and mine closure, since it prevents the formation of AMD, presenting significant advantages when compared to technologies used today.
When this project is completed, we hope to continue scaling the technology through industrial scale testing at Chilean mining operations. This will allow us to ensure the quality of water at the operational phase and, more so, for the closure phase, and design and implement an integrated acid or contact water treatment system with low costs of installation and operation based on the prevention of AMD generation.
Photo 1. Mine drainage from Mina Chiflón del Diablo, Lota, Biobío Region, Chile (Source: https://sabes.cl/2018/08/17/esta-hermosa-playa-lota-estaria-siendo-contaminada-residuos-chiflon-del-diablo/)
Photo 2. Mine drainage, Biobío Region, Chile (Source: Iván Ñancucheo).