Environmental desulfurization as a tool to improve mine waste management and mine site reclamation

包括尾矿在内的矿山废物管理是采矿作业的最重要挑战。面向上游的方法将有利于优化尾矿管理。通过泡沫浮选进行的环境脱硫允许回收尾矿中的大多数硫化物矿物，以显著降低其反应性，从而使其在化学上适合作为矿山废物回收的覆盖材料。然而，没有研究脱硫对尾矿水文地质性质的影响。这些特性，特别是颗粒尺寸分布，可能会被脱硫过程改变，并最终影响由脱硫尾矿制成的覆盖系统的性能。此外，通常的方法来确定覆盖系统的材料的化学充分性涉及静态和动态测试，这往往是不充分的材料具有低反应性，并提供非常有限的信息，长期性能的材料作为覆盖。水文地球化学数值模拟用于预测低活性废石的长期行为;然而，需要更多的工作来整合与低活性材料相关的具体方面。另一个值得研究的问题是，是否可能利用环境脱硫技术对旧尾矿池进行再处理，通过生产经过净化的尾矿来减少尾矿场的环境责任，从而促进场地复垦，同时回收过去没有回收的有价值金属。拟议的研究计划致力于整合矿物加工和环境管理，以优化尾矿管理，虽然环境脱硫作为一种手段，以生产具有足够的水文地质特性的材料，用于矿场复垦。该项目有三个目标：1）研究浮选环境脱硫对尾矿水文地质性质的影响; 2）使用数值模型模拟脱硫尾矿的水文地球化学行为; 3）评估环境脱硫作为老尾矿的回收方法的使用。用于实现这些目标的方法将包括详细的材料表征（水文地质学、地球化学、矿物学）、浮选试验、动力学试验和数值模拟。将根据实验室和现场数据开发数值模型，如Vadose/W和MIN 3 P，以确定脱硫目标，确保生产的脱硫尾矿具有足够的特性（地球化学和水文地质），可长期用作成功的覆盖层（单层或多层系统的一部分）。该计划将培养本科生和研究生，从而为加拿大采矿业和研究界提供急需的采矿环境专家。

Mine waste management, including mine tailings, is the most important challenge of mining operations. An upstream-oriented approach would be beneficial for optimal tailings management. Environmental desulfurization, performed by froth flotation, allows recovering most sulfide minerals in the tailings to reduce significantly its reactivity, thus making it chemically suitable as cover material for mine waste reclamation. However, no studies were performed on the effect of desulfurization on tailings hydrogeological properties. Those properties, specifically particle size distribution, may be altered by the desulfurization process and ultimately affect the performance of cover systems made of desulfurized tailings. Furthermore, the usual methods to determine the chemical adequacy of materials for cover systems involve static and kinetic tests, which tend to be inadequate for materials that have low reactivity, and provide very limited information on long term performance of materials as covers. Hydrogeochemical numerical modelling was used to predict the long term behaviour of low reactive waste rock; however more work is required to integrate specific aspects related to low reactive material. Another aspect that deserves investigation is the possibility of using environmental desulfurization to reprocess old tailing ponds to facilitate site reclamation by producing decontaminated tailings that reduce the environmental liability of the site, while at the same time to recover valuable metals that were not recovered in the past.***The proposed research program strives to integrate mineral processing and environmental management to optimize tailings management, though environmental desulfurization as a mean to produce material with the adequate hydrogeological properties to be used in mine site reclamation. The program aims three objectives: 1) to study the effect of environmental desulfurization by flotation on the tailings hydrogeological properties; 2) to simulate using numerical models the hydrogeochemical behaviour of desulfurized tailings; 3) to evaluate the use of environmental desulfurization as a reclamation method for aged tailings. The methodology used to reach these objectives will comprise detailed material characterization (hydrogeological, geochemical, mineralogical), flotation tests, kinetic tests, and numerical modelling. Numerical models, such as Vadose/W and MIN3P will be developed based on laboratory and field data to determine the desulfurization targets to ensure that the desulfurized tailings produced have adequate properties (geochemical and hydrogeological) to be used as a successful cover (monolayer or part of a multilayer system) over the long term. The program will train undergraduate and graduate students, thus providing the Canadian mining industry and research community with much needed experts in mining environment.***