Release of Multiple Contaminants from Mine Waste Materials

采矿和矿物净化活动产生大量废石。当这些材料暴露于水和空气中时，各种有毒元素，如硒、砷、镍和镉，可能会被浸出并移动到接收沃茨和土壤中，对水质和水生生态系统产生重大影响。这些元素往往会同时出现和释放，而且往往具有不同的释放动态，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给政府和整个社会带来了负担。更可取的办法是从源头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污染源控制策略，必须获得有关废石堆中污染物释放动态的基本过程的可靠知识，如反应动力学、质量输送、热输送和微生物活动。 这项研究的长期目标是制定和实施各种源头控制战略，从源头上防止矿山废料释放多种有毒元素，从而减少对水处理的长期依赖。实现这一目标需要了解决定释放动态的关键过程的基本知识。因此，本研究在未来五年的短期目标是确定和模拟关键的地球化学和流体动力学过程，通过实验室测试和数值模拟控制污染物释放动态，重点是硒和相关元素（砷，镉，锶）从煤矿废物。 这项研究的结果将推进知识的释放动力学的多种有毒元素从矿山废料。这一知识将对研究多种有毒元素所造成的复杂环境和生态风险的其他研究人员有重要的用处。这将为制定环境准则提供科学依据。在源头上控制多种污染物释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制定切实可行的源头控制战略。开发的完全耦合模型允许不同的缓解策略的有效性进行评估，并选择替代方案。这将减少对水处理的长期依赖，这是一个昂贵的选择，可能会永远存在。这项研究还将提供一个示范性的框架，用于预测和管理多种有毒元素从各种废石中的释放。

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.