Mineralogical Characterization for Reducing the Environmental Impact of Mining Rare Metals

我的研究计划的目标是确定尾矿、废石和受污染的粉尘、土壤和沉积物中含有潜在危险金属的矿物或化合物的特征。通过对宿主金属物种、颗粒大小和质地的直接和定量鉴定，可以预测金属是会释放到水环境中，还是会以次生矿物的形式保留在固体废物中。这项研究的结果将改进加拿大拟建、运营和孤儿矿山的风险评估和补救设计，特别是在加拿大北部，那里将进行大量实地工作。研究结果将对政府监管机构、环境顾问、矿业公司和包括原住民在内的附近社区的决策者有用。更广泛的科学应用是澄清矿山废物对人类和生态健康的风险，以及预测这些材料在环境中的长期稳定性。*重点将放在含有稀土元素(REE)、铟、锂、Nb和钴等稀有和未被研究的金属的颗粒上，其中一些被称为关键或战略金属，因为它们对电子、绿色技术和军事应用非常重要。人们对这些元素的环境流动性的控制知之甚少，例如原生矿石矿物向次生风化产物的转化、胶体运输的重要性，或者尾矿库、湿地和土壤中宿主矿物的长期稳定性。*我将利用我在鉴定受砷和锑污染的矿山废物方面的现有专业知识。在尾矿、土壤、沉积物和粉尘中寻找和识别含有金属的颗粒是具有挑战性的，因为它们通常很小，很稀有，结晶性能很差。即使是超过监管规定的样品，散装浓度也可能远远低于0.1%。此外，在大多数样品中，存在多种金属矿物学宿主，区分它们并评估金属赋存相的相对比例是重要的。生物利用度和长期稳定性取决于宿主矿物的组成、其颗粒大小和质地关系，如被其他矿物包裹。在过去的六年里，我指导了32名研究生和博士后研究员，他们都在环境地球化学领域工作。拟议的计划将培训11名HQP，他们接触到先进的分析技术、世界级的合作者、广泛的实地工作，以及与社区、政策制定者和行业的互动，这些都将使用他们的研究。这个项目将受益于我在加拿大北部的经验以及与矿业公司、原住民和政府机构的持续合作。**

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.**