Release of Multiple Contaminants from Mine Waste Materials

采矿和选矿活动产生了大量的废石。当这些物质暴露在水和空气中时，各种有毒元素，如硒、砷、镍和镉，可能被淋出并动员到接收水和土壤中，对水质和水生态系统造成重大影响。这些元素往往一起发生和释放，更常见的是不同的释放动力学，因此构成复杂的环境和生态风险。 目前处理矿井排水的普遍做法是安装水处理设施。管理长期水处理的费用和复杂性对政府和整个社会构成了负担。更可取的选择是从源头上防止有毒元素的释放，即源头控制。为了选择和实施最合适的源头控制策略，必须充分了解决定废石堆污染物释放动力学的基本过程，如反应动力学、质量传输、热传输和微生物活动。 这项研究的长期目标是制定和实施各种源头控制战略，以防止矿山废物从源头释放多种有毒元素，从而减少对水处理的长期依赖。要实现这一目标，需要对决定发布动态的关键流程有基本的了解。因此，这项研究在未来五年的短期目标是通过实验室测试和数值模拟来确定和模拟控制污染物释放动力学的关键地球化学和流体动力学过程，重点是从煤矿废物中提取硒及其相关元素(砷、镉、锶)。 这一研究结果将促进人们对矿山废物中多种有毒元素释放动力学的认识。这一知识将对研究多种有毒元素构成的复杂环境和生态风险的其他研究人员具有重要作用。总而言之，它将为制定环境指南提供科学依据。关于在源头控制多种污染物排放的关键参数的研究结果将有助于采矿业和监管机构通过操纵这些关键参数来制定切实可行的源头控制战略。所开发的完全耦合模型允许评估不同缓解战略的有效性并选择替代方案。这将减少对水处理的长期依赖，这一昂贵的选择可能会延续到永远。这项研究还将为预测和管理从各种废石中释放多种有毒元素提供一个示范框架。

Large volumes of waste rocks are generated by mining and mineral beneficiation activities. When these materials are exposed to water and air, various toxic elements, such as selenium, arsenic, nickel, and cadmium, may be leached out and mobilized to receiving waters and soil, resulting in significant impacts on water quality and aquatic ecosystems. These elements tend to occur and are released together, more often with different release dynamics, therefore posing complex environmental and ecological risks. The current common practice to deal with mine drainage is the installation of water treatment facilities. The expense and complexity of managing long-term water treatment poses a liability to government and society as a whole. A more preferable option is to prevent the release of toxic elements at the source, i.e. source control. To select and implement the most appropriate source control strategies, it is essential to obtain sound knowledge on the fundamental processes that determine the dynamics of contaminant release from waste rock piles, such as reaction kinetics, mass transport, heat transport, and microbial activities. The long-term objective of this research is to develop and implement various source control strategies to preclude the release of multiple toxic elements from mine waste materials at the source, thus reducing long-term reliance on water treatment. Achieving this objective requires fundamental knowledge on the key processes that determine the release dynamics. Therefore, the short-term objectives of this research over the next five years are to identify and simulate the key geochemical and hydrodynamic processes that control contaminant release dynamics via laboratory test and numerical modelling, with a focus on selenium and associated elements (arsenic, cadmium, strontium) from coal mine waste. The findings of this research will advance knowledge on the release dynamics of multiple toxic elements from mine waste materials. This knowledge will be of important use to other researchers who study the complex environmental and ecological risks posed by multiple toxic elements. Together, it will provide the scientific bases for the establishment of environmental guidelines. The findings on key parameters that control multiple contaminant release at the source will assist the mining industry and regulators in developing practical source control strategies by manipulating those key parameters. The fully-coupled model developed allows for the evaluation of the effectiveness of different mitigation strategies and selecting alternatives. This will reduce long-term reliance on water treatment, an expensive option that may extend into perpetuity. This research will also provide an exemplary framework for predicting and managing the release of multiple toxic elements from a diversity of waste rock.