Sustainable mine waste management: from microscale hydrogeochemical processes to macroscale prediction models

可持续矿山废物管理：从微观水文地球化学过程到宏观预测模型

• 批准号: RGPIN-2021-03133
• 负责人: Vriens, Bas
• 金额: $ 2.19万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=754996
• 关键词: Sustainable; mine; waste; management; microscale

*INTRODUCTION* Mine wastes can negatively impact the environment through the release of poor-quality drainage with harmful levels of acidity, metal(loid)s or other contaminants. Effective long-term management of mine waste storage facilities is predicated on the ability to forecast seepage rates and the chemical composition of these effluents for decades beyond mine closure. For this, a wide range of geochemical weathering reactions and coupled physical transport processes needs to be quantitatively understood. Mineralogical dynamics, effluent composition and solute speciation vary greatly across storage conditions and waste rock types but lack systematic characterization to date. Furthermore, our ability to integrate such microscale hydrogeochemical phenomena with practical, macroscale prediction models is still limited: effective waste management remains a costly technical challenge for the mining industry. *OBJECTIVES* The objectives of this research program are to advance our understanding of critical hydrogeochemical processes in mine wastes and to improve the application of this knowledge in prediction models for mine waste effluent quality. The proposed research occurs along two major themes: microscale processes and macroscale prediction models. These themes, respectively, have the objectives to i) experimentally constrain the controls of mineralogical dynamics and aqueous solute speciation on weathering rates and contaminant mobility, and ii) to create and evaluate long-term macroscale prediction models using reactive-transport modeling and dimensionless numbers analyses. *METHODS* Using controlled laboratory experiments, we will study the weathering rates, mineralogical surface dynamics and generated effluent qualities from different waste rock materials under contrasting exposure conditions. By analyzing the aqueous speciation of thiolated metalloids in effluent, we will determine the conditions in which these contaminant species are formed and degraded and thereby shed light on their environmental persistence. Second, we will monitor and quantify the evolution of the mineral assemblages and derive kinetic parameters and indicator proxies for bulk waste rock reactivity that can ultimately be used in prediction models. Finally, we will perform reactive-transport simulations to assess the importance of distinct hydrogeochemical, mineralogical, and physical transport processes towards overall drainage quality as a function of waste rock type and storage conditions. *IMPACT* This research program will train several graduate and undergraduate students in advanced analytical, experimental, and simulation techniques, using world-class infrastructure and extensive collaboration with (international) mining practitioners. Our results will produce fundamental knowledge on mine waste hydrogeochemistry as well as practical insights for improved mine waste management, helping Canadian companies to remain global frontrunners in sustainable mining.

*简介*矿山废物可通过释放含有有害酸度的劣质排水、金属(固体)S或其他污染物而对环境产生负面影响。对矿山废物储存设施的有效长期管理取决于在矿山关闭后几十年内预测渗漏率和这些流出物的化学成分的能力。为此，需要对广泛的地球化学风化反应和耦合的物理传输过程进行定量的了解。矿物学动力学、污水组成和溶质形态因储存条件和废石类型的不同而有很大差异，但迄今缺乏系统的表征。此外，我们将这种微观尺度的水文地球化学现象与实际的宏观尺度预测模型相结合的能力仍然有限：有效的废物管理对采矿业来说仍然是一项代价高昂的技术挑战。*目标*本研究计划的目的是促进我们对矿山废物中关键的水文地球化学过程的理解，并改进这一知识在矿山废物水质预测模型中的应用。拟议的研究围绕两个主要主题展开：微观过程和宏观预测模型。这些主题的目标分别是：i)通过实验限制矿物动力学和水溶质形态对风化速率和污染物迁移率的控制，以及ii)使用反应迁移模型和无量纲数字分析来创建和评估长期宏观尺度预测模型。*方法*利用受控实验室实验，研究不同废石材料在不同暴露条件下的风化速率、矿物学表面动力学和产生的污水水质。通过分析废水中硫化类金属的水相形态，我们将确定这些污染物物种的形成和降解条件，从而揭示它们在环境中的持久性。其次，我们将监测和量化矿物组合的演变，并得出最终可用于预测模型的散装废石反应性的动力学参数和指示指标。最后，我们将进行反应传输模拟，以评估不同的水文地球化学、矿物学和物理传输过程对总体排水质量的重要性，作为废石类型和储存条件的函数。*影响*该研究项目将利用世界级的基础设施和与(国际)矿业从业者的广泛合作，在高级分析、实验和模拟技术方面培训几名研究生和本科生。我们的成果将产生有关矿山废物水文地球化学的基础知识，并为改进矿山废物管理提供实际见解，帮助加拿大公司在可持续采矿领域保持全球领先地位。