Physical and chemical durability of bituminous geomembranes sheets and welds in heap leach pads

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The mining sector is of strategic importance since Canada is one of the largest mining nations in the world, producing more than 60 minerals/metals that directly employs more than 373,000 workers and contributed $56B to Canada's GDP in 2015. Geomembranes, typically thin plastic sheets, are used as the liners in mineral extraction facilities to prevent economic loss (lost minerals) and protect the surrounding environment from the migration of the contaminants. Mining applications considerably involve high vertical stresses imposed on the liner that can result in puncturing the thin plastic liner and hence poses risks of contaminating the surrounding surface and ground waters. Although bituminous geomembranes (BGM; multicomponent products comprised of a combination of a waterproof bituminous binder with a geotextile layer) have been around for 20-30 years, historically their use has been limited to use in canals, potable water reservoirs, and other low environmental risk applications. BGMs are often considered to be favourable for such high overburden pressure mining applications due to their claimed high puncture resistance and currently used despite a lack of knowledge of their behaviour. This project seeks to understand how BGMs will interact with aggressive field conditions found in mining application in scenarios in which plastic geomembranes puncture and degrade. The proposed work aims to reduce the risks associated with puncturing and ageing of the geomembrane liners during or after installation by the proper selection of the BGM product and the identification of the cases where geosynthetic protection may be required to be used in conjunction with the BGMs. Queen's University has the unique expertise and equipment necessary for simulating the field exposure conditions in the laboratory. Collaboration with a leading geosynthetic installer will ensure experimental conditions reflect common field conditions and that the research findings are applied to real life challenges that are currently facing the industry. The research will involve training of four HQP.