Review of Store and Release Cover Trials and Recommendations for Improved Rehabilitation of Mine Waste Structures

Mine waste cover systems are commonly used to manage acid and metalliferous drainage (AMD); however, their long-term performance is often variable and may not always meet design objectives. Field trials are relied upon to demonstrate cover design performance prior to final landform construction, yet few have unequivocally demonstrated their performance at scale. This research critically reviews mine waste cover system field trials and recommends approaches to plan and implement trials that successfully demonstrate cover performance. Studies reporting mine waste cover field trials on store and release covers were reviewed against criteria that represent critical components of a trial (i.e., description of the design of the study and waste covers, material characterisation, objectives, construction, monitoring, results and limitations). The review found trial objectives, experimental design and approaches used to interpret results vary widely between studies. No studies presented information describing the life cycle of a trial from planning, design, implementation and reporting. Trials were influenced by variation in weather experienced during the trial period, had high rates of monitoring equipment failure, and lacked quality assurance procedures to verify covers were constructed to design specifications. Incomplete or unsuccessful field trials present a risk to decision making and may delay rehabilitation. Recommendations are made for further research to test and standardise approaches to design, implement and report on mine waste cover trials aimed at ensuring trials meet their objectives and enhance their role in informing mine rehabilitation.