Passive Approaches for Long-term Management of Mine Wastes and Hazardous Substances

加拿大拥有丰富的矿产资源，提供了建筑、交通、能源和通信系统所需的金属(如铜、锌和镍)和特殊元素(如钴、铂族元素)的来源。开采这些资源会产生大量的废物，包括废石、磨尾矿和炼油厂废物。地下水和附近的地表水体经常受到高浓度有毒金属、类金属和来自这些废物的其他无机和有机污染物的影响。硫化物矿物氧化产生的酸导致碳酸盐矿物的溶解和温室气体(GHG)排放的增加。迫切需要制定和评估减少矿场有毒物质排放和减少温室气体排放的低成本办法的有效性。该研究计划有三个主要主题：i)评估现有管理方法(提高地下水位、低渗透覆盖系统、有机碳基覆盖系统)稳定尾矿的有效性，ii)确定用于矿场和其他复垦活动的有机碳废物(OCWM)(例如城市生物固体、垃圾堆肥)中新出现的令人关注的污染物(EOCs)的释放情况，以及iii)修改OCWM以促进EOCs和矿源有毒元素的稳定或降解。研究将在已安装或计划安装修复系统的矿场进行，包括将OCWM用于尾矿覆盖系统或用作生长介质以恢复植被的矿场。将在覆盖系统和下面的尾矿中收集固体、气体和水相样本，以评估覆盖材料的有效性和寿命，以及覆盖系统对温室气体排放的影响，以及对尾矿矿物学和孔隙水化学的影响。将使用常规矿物学技术进行详细的固相分析，并辅之以先进的同步加速器光谱分析。水分析将包括主要和痕量元素分析。将通过电喷雾串联质谱仪和下一代Orbitrap质谱仪对OCWM中EOCs(如全氟烷基磺酸盐)的浸出进行评估。将进行辅助研究，以评估OCWM通过不同的处理方法(例如，热解以稳定碳、添加矿山废物衍生的改良剂以提高反应性)的效果，以用作反应介质，以控制覆盖材料中、工程岸边稳定系统中以及被动反应堆和可渗透反应屏障中的污染物。改进管理办法的应用将通过节省成本和提供有效的补救方法使加拿大和世界受益，这些方法还可以减少温室气体排放，改善受采矿和工业活动影响最大的当地社区和生态系统的健康状况。

Canada has abundant mineral resources that provide a source of metals (e.g., Cu, Zn and Ni) and specialized elements (e.g., Co, platinum group elements) required for buildings, transportation, energy, and communication systems. Extraction of these resources generates large volumes of waste materials, including waste rock, mill tailings, and refinery waste. Groundwater and nearby surface water bodies are frequently impacted by high concentrations of toxic metals, metalloids, and other inorganic and organic contaminants derived from these wastes. Acid generated through sulfide mineral oxidation causes dissolution of carbonate minerals and an increase in green-house gas (GHG) emissions. There is a pressing need to develop and evaluate the effectiveness of low-cost approaches to reduce both the release of toxic substances from mine sites and to lower GHG emissions. The research program has three principal themes: i) evaluating the effectiveness of existing management approaches (raised water table, low permeability cover systems, organic carbon-based cover systems) to stabilize tailings, ii) identifying the release of emerging contaminants of concern (EOCs) from organic carbon waste materials (OCWM) (e.g., municipal biosolids, landfill compost) used in mine site and other reclamation activities, and iii) modifying OCWM to promote stabilization or degradation of EOCs and mine-derived toxic elements. Research will be conducted at mine sites with previously installed or planned remediation systems, including sites where OCWM is utilized for tailings cover systems or as growth media for revegetation purposes. Solid-, gas- and aqueous-phase samples will be collected within the cover systems and underlying tailings to evaluate the effectiveness and longevity of the cover materials, and the impact of cover systems on GHG emissions, and on tailings mineralogy and pore-water chemistry. Detailed solid-phase analyses will be conducted using conventional mineralogical techniques and supplemented with advanced synchrotron-based spectroscopy. Water analyses will include major and trace elemental analyses. Leaching of EOCs (e.g., perfluorinated alkyl sulfonates) from OCWM will be evaluated through electrospray tandem mass spectrometry and next generation Orbitrap mass spectrometry. Ancillary studies will be conducted to evaluate the effects of OCWM through different treatments (e.g., pyrolysis to stabilize C, addition of mine-waste derived amendments to enhance reactivity) for use as reactive media for control of contaminants in cover materials, within engineered bank stabilization systems, and in passive reactors and permeable reactive barriers. Application of improved management approaches will benefit Canada, and the World, through cost savings and by providing effective remediation methods, which also reduce GHG emissions, and improve the health of local communities and ecosystems most impacted by mining and industrial activities.