Alternative closure methods for mine openings at remote legacy mines


Dr David Sanscartier, Mrs Patty Ogilvie-Evans

Saskatchewan Research Council (SRC) is managing the remediation of 37 legacy mines on public land in northern Saskatchewan, Canada on behalf of the Saskatchewan Ministry of the Economy. Sites include openings to the underground that require proper closure to ensure long-term public safety. In Saskatchewan, the legislated requirement is to close openings with a reinforced concrete bulkhead designed by a professional engineer. This is challenging in remote locations with no road access or where access is limited to an ice road for a four- to six-week period during the winter. Since the outset of Project CLEANS, various alternative methods have been implemented successfully: stainless steel caps, boulder covers, waste rock backfills, and polyurethane foam plugs. These methods have gained acceptance from the regulators as safe and durable mine closure methods for remote sites, and are slowly being utilized by other projects in Saskatchewan and in other jurisdictions. In addition to meeting regulatory requirements, the approach selected must meet criteria such as: competitive life cycle cost, sufficient service life, ease of transport, prevent unauthorised access, withstand forest fires, ease of installation, minimal field fitting. This presentation will present the different methods applied by SRC and lessons learned from their application.