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Stories from a quarter century of cover system design : Learnings to inform the future

British Columbia Mine Reclamation Symposium; University of British Columbia. Norman B. Keevil Institute of Mining Engineering

For over twenty-five years, Okane has designed, built, and monitored cover systems for tailings storage facilities and mine rock stockpiles across British Columbia. Typical terminology within the industry refers to “water covers” and “dry covers”. Dry Covers, or cover systems that result in primarily a terrestrial ecosystem, is the focus of this paper. They are the building blocks for achieving future, or returning, land use, and providing a stable, reliable, and sustainable interface between a mine landform and the environment. With, primarily, a warm humid continental and oceanic climate, British Columbia is a unique environment for cover system design. Performance expectation, from a technical perspective, is strongly influenced by the geologic and hydrogeologic system at a mine site. Cover system performance itself is largely dictated by water management, freeze-thaw and wet-dry cycles, and storm events. Each site can also have many microclimates that will impact not just cover system performance but long-term revegetation potential. As new projects explore alternative waste disposal methods, including filtered tailings and codisposal options, modelling of both saturated and unsaturated zone hydrology will need to consider new land-climate interactions, including land use(s) that are not solely focussed on achieving ecological restoration. Risk-based decisions, informed by geochemical stability will have a greater impact on geotechnical stability; closure criteria requirements for cover systems will evolve. There also remains a need for specific focus on the key aspects influencing cover system functionality to communicate, on a site-specific basis, that cover systems are ‘proven technology’, as defined by the Province’s Technical Readiness Assessment (TRA) guidance, to manage water and water quality risk. This paper highlights key considerations for designing cover systems in British Columbia, historical lessons learned, and factors to consider when designing for future climate change scenarios.

Conference Paper

eng

Vancouver : University of British Columbia Library

10.14288/1.0447215

Non UBC

Other

DSpace