School of Minerals and Energy Resources Engineering, The University of New South Wales-Sydney, Australia

Dr. Carlito Baltazar Tabelin is an environmental geochemist competent in the fields of inorganic contaminant geochemistry, rock-soil-water interactions, geochemical and reactive transport modelling, electrochemistry, mine waste management, prevention/control of acid mine/rock drainage (AMD/ARD), and remediation of contaminated sites. He earned his Ph.D. in Field Engineering for Environment from Hokkaido University in 2011. After his graduation, he worked as a Postdoctoral researcher at Hokkaido University before being promoted to assistant professor in 2013. He was awarded two research grants from the prestigious Japan Society for the Promotion of Science (JSPS) as principal investigator to develop advanced pyrite passivation techniques to limit AMD formation. He moved to Australia in 2019 and joined the School of Minerals and Energy Resources Engineering at UNSW-Sydney. Dr. Tabelin has authored/co-authored many academic papers published in prestigious journals, presented in numerous international conferences, and reviewed for leading environmental science/engineering journals like Water Research, Geochimica et Cosmochimica Acta, Science of the Total Environment, Chemosphere, Waste Management, and Environmental Pollution.

Speech Title: Development of advanced pyrite passivation strategies towards sustainable management of acid mine drainage

Abstract: Acid mine drainage (AMD) is one of the most serious environmental problems encountered in mining areas worldwide. When released into the environment without treatment, AMD pollutes the surrounding water bodies and soils with hazardous and toxic elements like arsenic (As), selenium (Se) and heavy metals such as lead (Pb), cadmium (Cd), copper (Cu) and zinc (Zn) that rapidly destroy affected ecosystems. The most commonly used method to treat AMD is chemical neutralization, a technique whereby basic materials like limestone or lime are mixed with AMD to raise its pH and remove most of the contaminants via precipitation. Although effective, this approach requires the continuous supply of chemicals, energy, and manpower, which makes it unsustainable because AMD generation has been documented to continue for a very long time (centuries to millennia).

One promising alternative to chemical neutralization is (micro)encapsulation, a technique that directly treats pyrite, the main mineral responsible for AMD formation, and renders it unreactive by encapsulating the with protective coatings. In this study, we introduce two advanced pyrite passivation techniques to limit AMD formation called carrier-microencapsulation (CME) and galvanic microencapsulation (GME). CME uses a redox-reactive organic carrier to deliver the coating material on the surface of pyrite. Because the carrier only decomposes on pyrite, the primary strength of this technique is its high selectivity for pyrite even in complex systems like mine tailings and pyrite-rich waste rocks. Meanwhile, GME is based on galvanic interactions between pyrite and metals with lower rest potentials, so this technique could be applied directly in a ball mill during ore processing or coal cleaning.