Alternative materials for engineered covers used to control acid mine drainage

用于控制酸性矿山排水的工程覆盖层的替代材料

• 批准号: RGPIN-2016-05667
• 负责人: Bussière, Bruno
• 金额: $ 4.37万
• 依托单位: Université du Québec en Abitibi-Témiscamingue
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=690899
• 关键词: Alternative; materials; engineered; covers; used

One of the most serious environmental challenges facing the mining industry today is the reclamation of mine waste disposal areas, especially when they contain sulphide minerals that can produce acid mine drainage (AMD). The proposed research program seeks to improve cover technologies through the use of alternative materials as cover components, and is divided into two distinct projects: 1) assessment of paste rock as cover material; 2) assessment of bentonite based fine grained materials in engineered covers.****In Project 1, paste rocks with different waste rock to tailings ratios will be prepared, characterized, and tested. The performance of the paste rock mixtures will be compared, in terms of hydrogeological properties, with theoretical predictions made using Mixture theory. The results of large-scale column tests, in which paste rocks are used as cover material, will be compared with the results from existing field experimental cells. Both set-ups will be instrumented to measure unsaturated water movement and gas migration, and will allow for leachates to be recovered. Results obtained from the physical models (column tests and field experimental cells) will be compared with those from hydrogeochemical numerical models.****Bentonite-based fine-grained materials (soil-bentonite or geocomposite clay liner (GCL) are interesting options as cover materials when traditional fine-grained materials are not available near the mine site. Recent work performed by the candidate demonstrated that rock-bentonite mixtures are efficient in controlling oxygen migration over short periods, but are significantly influenced by freeze-thaw cycles. In Project 2, a detailed characterization of different soil bentonite mixtures will be performed in the lab. Based on the results of the characterizations, instrumented column tests in a temperature-controlled chamber will be performed to assess the performance of bentonite-based covers in controlling oxygen and water migration when exposed to freeze-thaw cycles. GCL will also be investigated in this project as a fine-grained layer used in engineered covers. The candidate has access to a mine site where GCL is used as an existing cover material. Laboratory tests (e.g., water and air permeability, microstructural characterization) on intact, post-freeze-thaw cycles, and in situ samples will be performed to evaluate the capacity of GCL to control fluid (water and gas) movement when installed at AMD-generating mine sites.****The proposed research program will provide new or improved techniques for the reclamation of AMD-generating mine waste disposal areas. The work will be performed by HQP, who will benefit from this training by becoming highly-valued specialists with the knowledge and ability to reduce the environmental impacts of mining, while supporting the industry's goal of sustainable exploitation of metal resources.******

当今采矿业面临的最严重的环境挑战之一是矿山废物处理区的复垦，特别是当它们含有可产生酸性矿山排水（AMD）的硫化物矿物时。拟议的研究计划旨在通过使用替代材料作为覆盖层组件来改进覆盖层技术，并分为两个不同的项目：1）评估作为覆盖层材料的膏体岩石； 2) 工程覆盖层中膨润土基细粒材料的评估。****在项目 1 中，将制备、表征和测试具有不同废石与尾矿比例的膏体岩石。糊岩混合物的性能将在水文地质特性方面与使用混合物理论做出的理论预测进行比较。使用糊状岩石作为覆盖材料的大规模柱试验的结果将与现有现场实验室的结果进行比较。这两个装置都将配备仪器来测量不饱和水运动和气体迁移，并将允许回收渗滤液。从物理模型（柱测试和现场实验单元）获得的结果将与水文地球化学数值模型的结果进行比较。****当矿场附近没有传统的细粒材料时，基于膨润土的细粒材料（土壤-膨润土或土工复合粘土衬垫（GCL））是作为覆盖材料的有趣选择。候选人最近进行的工作表明，岩石-膨润土混合物可有效控制短期内的氧气迁移 期，但受冻融循环的影响显着。在项目 2 中，将在实验室中对不同土壤膨润土混合物进行详细表征。根据表征结果，将在温控室中进行仪表柱测试，以评估膨润土基覆盖物在暴露于冻融循环时控制氧气和水迁移的性能。协鑫也将被调查 项目作为工程覆盖物中使用的细粒度层。候选人可以进入一个矿区，那里使用 GCL 作为现有的覆盖材料。将对完整的冻融循环后样品和原位样品进行实验室测试（例如水和空气渗透性、微观结构表征），以评估 GCL 安装在产生 AMD 的矿井时控制流体（水和气体）运动的能力 ****拟议的研究计划将为产生 AMD 的矿山废物处理区的复垦提供新的或改进的技术。这项工作将由 HQP 执行，HQP 将从此次培训中受益，成为具有减少采矿对环境影响的知识和能力的高价值专家，同时支持该行业实现金属资源可持续开采的目标。******