Revegetation layer influence on the water balance of mine reclamation covers

保证矿渣贮存设施中活性物质的长期化学稳定性是矿山场地复垦的主要问题之一，通常采用工程覆盖来解决这一问题。这种覆盖物的目的是限制从废物中排放的水的污染，通常是通过控制氧迁移和/或水向下渗透到活性废物中。覆盖物的有效性取决于控制覆盖物中水分平衡（WB）的重要组成部分的能力，包括入渗、蒸散发和水分储存的变化。植被的存在可以通过根系抽吸和蒸腾作用减少被盖的水分含量。植物还可以通过根系创造生物孔和有机质富集来改变覆盖物质的水文地质性质。这些变化可以影响渗透速率和覆盖层的储水量。这一跨学科项目的主要目标是更好地校准和模拟植被对矿山复垦覆盖的WB的影响，以确保其长期性能。三个实验将在三个不同的矿井现场进行，在中等规模（10 × 10米细胞）和现场范围内进行。在低硫废石或尾矿和以脱硫尾矿为单层并结合高架地下水位回收的产酸尾矿两种情况下，在围垦盖设计中增加植被层。所提出的研究将有助于更好地量化植被层对工程覆盖层性能的正面和负面影响。两名博士研究生，一名硕士研究生和一名博士后研究员将接受培训，并将为满足行业对可持续矿区开垦实践发展中熟练劳动力的需求做出贡献。

Ensuring the long-term chemical stability of reactive materials in mine waste storage facilities is one of the main issues in mine site reclamation, and engineered covers are commonly used to address this problem. The goal of such covers is to limit the pollution of water draining from the wastes, usually by controlling oxygen migration and/or water infiltration downward into the reactive wastes. The effectiveness of a cover relies on the ability to control important components of the water balance (WB) in the cover materials, including infiltration, evapotranspiration, and variation in water storage. The presence of vegetation on covers can reduce their water content through root pumping and transpiration. Plants can also change the hydrogeological properties of the cover materials through creation of biopores by roots and organic matter enrichment. These changes can impact infiltration rates and water storage in the cover. The main objective of this interdisciplinary project is to better calibrate and model the impact of vegetation on the WB of mine reclamation covers to ensure their long-term performance. Three experiments will be performed on site at three different mines, at the intermediate scale (10 × 10 m cells) and site-wide scale. Vegetated layers will be added to the designs of reclamation covers in two contexts: low-sulfur waste rocks or tailings, and acid-generating tailings reclaimed with a monolayer made of desulfurized tailings and combined with an elevated water table. The proposed research will help to better quantify the positive and negative effects of vegetated layers on the performances of engineered covers. Two PhD students, one MSc student, and one post-doctoral researcher will be trained and will contribute to fulfilling industry demands for skilled labor in the development of sustainable mine site reclamation practices.