GEO-CM: Biogeochemical Processes Affecting Critical Mineral Hosts in Mine Tailings and Weathered Ore Zones

需要新的国内关键矿物资源来支持可持续的经济。稀土元素是电动机和风力涡轮机磁铁所必需的，而铂族元素是车辆催化转换器和先进化学加工所必需的，但这两种资源主要来自国外。矿山废石是稀土元素的理想宿主，可以重新利用已经从地下开采出来的材料。同样，地球表面暴露的矿岩带和冲刷到附近溪流中的物质代表了铂族元素的潜在新来源。这些资源类型中关键矿物的可用性以及提取它们的能力都是不确定的，因为这些材料已经被太阳、风和雨的作用风化了。该项目将调查风化如何影响美国三个不同地点矿山废物和暴露矿区的关键矿物。通过与工业界和政府合作伙伴合作，评估新的国内关键矿产资源，获得的新见解将提高美国的经济竞争力，并加强国家安全。该项目还将通过培训研究生和本科生掌握关键矿物这一国家迫切需要的领域，帮助发展国内的科学工作队伍。此外，它还将鼓励来自不同背景的高中生从事科学事业。该项目的主要研究重点是地球表面不同关键矿物资源的材料特征。对密苏里州Pea Ridge矿废料的研究将确定稀土元素在氧化铁-磷灰石尾矿风化过程中如何调动和重新分布，包括硫化矿物氧化产生的酸。在加州的帕斯山矿山，对尾矿的调查将显示这些相同的元素是如何在碳酸盐岩矿石废料的风化过程中转变的。蒙大拿州Stillwater复合体风化矿带的评估将评估铂族元素如何在氧化铁矿物中转化和潜在积累。该项目将采用先进的微量分析表征工具以及同步加速器光源的x射线技术来表征这些矿山尾矿和风化矿石带中的关键矿物。这项研究将提高我们对新型国内关键矿产资源形成的理解，并支持提高美国资源开采的可持续性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

New domestic resources of critical minerals are needed to support a sustainable economy. Rare earth elements are necessary for magnets in electric motors and wind turbines while platinum group elements are essential for catalytic converters on vehicles and for advanced chemical processing, but both resources are primarily obtained from foreign sources. Mine waste rocks represent promising hosts for rare earth elements, enabling reuse of materials already removed from the ground. Similarly, zones of ore rocks exposed at Earth’s surface and materials washed into nearby streams represent potential new sources of platinum group elements. The availability of critical minerals in these resource types, and the ability to extract them, are uncertain because these materials have been weathered by the action of sun, wind, and rain. This project will investigate how weathering affects critical minerals in mine wastes and exposed ore zones at three different locations in the United States. The new insight gained will improve the economic competitiveness of the U.S. and enhance national security by evaluating new domestic critical mineral resources through collaboration with industry and government partners. The project will also aid in the development of a domestic scientific workforce by training graduate and undergraduate students in critical minerals, an area of urgent national need. Further, it will encourage high school students from diverse backgrounds to pursue careers in science.The primary research focus of the project is the characterization of materials from distinct critical mineral resources at Earth’s surface. Study of waste materials from the Pea Ridge mine in Missouri will determine how rare earth elements mobilize and redistribute during weathering of iron oxide-apatite tailings, including from acid generated by sulfide mineral oxidation. At the Mountain Pass mine in California, investigation of tailings will show how these same elements transform during weathering of carbonatite ore waste materials. Evaluation of weathered ore zones in the Stillwater Complex in Montana will assess how platinum group elements transform and potentially accumulate in iron oxide minerals. The project will employ advanced microanalytical characterization tools as well as X-ray techniques at synchrotron lightsources to characterize the critical mineral occurrences in these mine tailings and weathered ore zones. This research will improve our understanding of the formation of novel, domestic critical mineral resources and support increased sustainability of resource extraction in the United States.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.