Mineralogical Characterization for Reducing the Environmental Impact of Mining Rare Metals

点击翻译按钮获取中文摘要

The objective of my research program is to characterize the minerals or compounds that contain potentially hazardous metals in mine tailings, waste rock and contaminated dust, soils and sediments. By direct and quantitative identification of the host metal species, particle size and texture, I can predict whether metals will be released to the aquatic environment or retained in the solid waste in the form of secondary minerals. The results of this research will improve risk assessment and remediation design for proposed, operating and orphaned mines in Canada, especially in the Canadian North where much of the fieldwork will occur. The results will be useful to decision-makers such as government regulators, environmental consultants, mining companies, and nearby communities including First Nations. The broader scientific application is the clarification of the risk to human and ecological health associated with mine waste, and prediction of the long-term stability of these materials in the environment.****The emphasis will be on particles that contain rare and understudied metals such as rare earth elements (REEs), indium, lithium, niobium and cobalt, some of which are termed critical or strategic metals as they are important for electronics, green technology and military applications. Very little is known about the controls on environmental mobility of these elements, such as the transformation of primary ore minerals to secondary weathering products, the importance of colloidal transport, or the long-term stability of the host minerals in tailings impoundments, wetlands and soils.****I will build on my established expertise in characterizing mine waste materials contaminated with arsenic and antimony. Finding and identifying metal-bearing particles in tailings, soils, sediments and dust is challenging as they are usually small, rare, and poorly crystalline. Even for samples that exceed regulatory guidelines, the bulk concentration may be much less than 0.1%. Moreover, in most samples, there are multiple mineralogical hosts of metals, and distinguishing these and evaluating the relative proportions of the metal-hosting phases is important. Bioavailability and long-term stability depend on host mineral composition, its particle size, and textural relationships, such as encapsulation by other minerals. ***I have supervised 32 graduate students and postdoctoral fellows in the last six years, all of whom are working in the field of environmental geochemistry. The proposed program will train 11 HQP with exposure to advanced analytical techniques, world-class collaborators, extensive fieldwork, and interaction with the communities, policy makers and industry that would use their research. This program will benefit from my experience in the Canadian North and ongoing collaboration with mining companies, First Nations, and government agencies.**