Optimization of filtered tailings deposition and reclamation for improved physical and chemical stability

最近，波利山、萨马尔科、卡迪亚山谷和布鲁马迪尼奥矿的尾矿坝坍塌，严重扰乱了传统的尾矿堆积模式。现在，大多数指南都在积极考虑和推荐新的方法，如过滤尾矿沉积，以提高尾矿储存设施(TSF)的物理稳定性。与传统的泥浆尾矿相比，脱水尾矿确实具有许多优势，并有助于降低土工风险和大坝坍塌的后果。然而，几个不确定因素，特别是与大气的相互作用和产生受污染矿井排水的风险，在某种程度上减缓了该技术的应用，特别是在加拿大。此外，在实践中，对过滤后的TSF的长期行为和回收进行的研究相对有限，该领域的大部分经验都是在已经运行的情况下获得的。然而，干式堆放将大大受益于更好的规划，因为时间是控制过滤尾矿水文岩土和地球化学行为的最关键因素。因此，“为结束而设计”的概念变得比以往任何时候都更加相关。因此，拟议的DG研究计划的主要目标是开发解决方案并优化活性过滤尾矿处置的规划，以更好地控制其短期和长期的水文地球化学和岩土稳定性。更具体地说，研究计划将分为两个主要的互补轴线：(1)优化过滤尾矿沉积，以降低运营期间产生酸性矿山废水(AMD)的风险(考虑到运营限制)；(2)开发针对过滤后TSF的临时和最终回收的创新解决方案。该研究计划将是高度多学科的，并将为过滤后的TSF的可持续处置和回收提供创新的解决方案。这项研究将通过HQP培训(3名博士、3名硕士和2名UG)进行，他们将成为该领域的明天的专家。公平、多样性和包容性将是HQP培训计划的核心。该研究计划将包括实验室测试、实地工作和高级数值模拟，并将有助于开发和采用针对采矿环境的创新方法方法。这项研究将增进对过滤尾矿短期和长期水文地球化学行为的了解。许多加拿大矿山认为干式堆放是降低岩土风险的一种方式，但由于不确定因素和缺乏处理酸性矿山废水的技术解决方案，他们对采取这条道路犹豫不决。在加拿大发展过滤尾矿处理将有助于降低未来TSF大坝坍塌的风险，从而改善邻近社区的安全、环境保护和整个社会的财富。

Recent tailings dam failures at Mount Polley, Samarco, Cadia Valley and Brumadinho mines have deeply disrupted the conventional tailings deposition paradigm. New approaches such as filtered tailings deposition are now actively considered and recommended by most guidelines to improve the physical stability of tailings storage facilities (TSF). Dewatering tailings has, indeed, many advantages over traditional slurry tailings, and contributes to reducing geotechnical risk and consequences of dam failures. However, several uncertainties, and in particular the interactions with the atmosphere and the risk for contaminated mine drainage generation, have somewhat slowed down the application of the technique so far, especially in Canada. Also, in practice, relatively limited research has been conducted on filtered TSF long-term behaviour and reclamation, and most of the experience in the field was gained while already operating. Dry stacking would, however, significantly benefit from better planning, as time is the most critical factor controlling filtered tailings hydrogeotechnical and geochemical behaviour. The concept of "Designing for closure" has thus become more relevant than ever. The main objective of the proposed DG research program is therefore to develop solutions and optimize the planning of reactive filtered tailings disposal to better control their hydrogeochemical and geotechnical stability in the short and long term. More specifically, the research program will be divided into two main complementary axes: (1) Optimization of filtered tailings deposition to reduce the risk of acid mine drainage (AMD) generation during operations (considering operational constraints); (2) Development of innovative solutions for temporary and final reclamation of filtered TSF. The research program will be highly multidisciplinary and will provide innovative solutions for the sustainable disposal and reclamation of filtered TSF. The research will be performed through HQP training (3 PhD, 3 MSc and 2 UG) who will become tomorrow's experts in the field. Equity, diversity, and inclusion will be central in the HQP training plan. The research program will include laboratory tests, field work, and advanced numerical simulations, and will contribute to developing and adapting innovative methodological approaches to mining environment. This research will improve knowledge about short- and long-term hydrogeochemical behaviour of filtered tailings. Research outcomes should be of interest for many Canadian mines which consider dry stacking as a way to decrease the geotechnical risks but hesitate to take this path because of uncertainties and lack of technical solutions to tackle acid mine drainage. Developing filtered tailings disposal in Canada would contribute to reducing the risk of TSF dam failures in the future, thus improving the safety of the neighbouring communities, the protection of the environment and the wealth of the society in general.