A devastating tailings pond spill in British Columbia has placed the storage of mine waste under the national microscope.
On Aug. 4, an estimated 500 cubic metres of toxic sludge burst through a dam at the Mount Polley mine tailings pond several hours northeast of Vancouver, various media outlets have reported.
The Reminder discussed Hudbay’s Flin
Flon area tailings pond – located entirely in Saskatchewan, near Creighton – with Scott Brubacher, director of corporate communications for the company.
REMINDER: How big is Hudbay’s Flin Flon tailings pond?
BRUBACHER: It is approximately 350 hectares and called the
Flin Flon Tailings Impoundment System (FFTIS), reflecting the wide-ranging design aspects: things like filters, drains, pumping systems that return water back to the tailing facility, water-retaining structures constructed with low-permeability materials such as clay, and concrete dams with spillways.
REMINDER How many new tailings are added to the pond each year?
BRUBACHER: Approximately 1.3 million tonnes of tailings annually are stored in the FFTIS.
REMINDER Could you describe the measures that Hudbay takes to ensure the safety of the FFTIS?
BRUBACHER: Dam stability and safety are maintained via ongoing comprehensive operational plans, including the FFTIS operations manual, monitoring programs, internal inspection programs and third-party independent engineering design and inspections.
This includes but is not limited to:
• Daily, weekly and monthly inspections conducted by trained Hudbay personnel. For example, daily inspections by the water sampling technologist are conducted to ensure that effluent quality is achieved 100 per cent of the time. As a result, they are conducted seven days per week and documented.
• Comprehensive annual inspections of the FFTIS by third-party geotechnical engineering consultants, including assessments of the dam stability.
• Deposition plans to manage projected tailings production are produced by third-party engineering consultants. Deposition means the sequence of locations where tailings are first discharged into the tailings impoundment system.
• Detailed geotechnical designs for annual construction work on the dams are completed by third-party consultants for review and approval from both Manitoba and Saskatchewan regulators. Tailings dams usually grow in height and size over time. They are designed and engineered to be raised in stages to accommodate an increasing volume of tailings, reflecting the continuing production from the ore body.
• An independent quality assurance / quality control monitoring program is in place during construction of dam raises.
• Inspection and monitoring of construction activities are performed by independent geotechnical engineering consultants.
• Upon completion of the construction, detailed as-built engineered drawings are produced by the geotechnical engineering consultant and provided to the regulators in an annual report.
Separate from the geotechnical engineering consultant used for annual inspections, an inspection and assessment is conducted every five years. This is referred to as a Dam Safety Review and is a requirement of the criteria of the Canadian Dam Association (CDA). The most recent inspection was completed this summer, of which no significant items were identified. We are currently awaiting the assessment and final report to be completed for filing.
REMINDER Is the FFTIS connected to other bodies of water? If there was a tailings pond failure here, would the water end up in other bodies of water?
BRUBACHER: Surface drainage moves northwards through the FFTIS, exiting from the North Weir into Flin Flon Creek, which drains into Ross Lake.
Approximately 1,384 hectares of surface drainage flows through the FFTIS, of which, 774 hectares, 56 per cent, are from the adjacent non-mining areas.
Saskatchewan and the Federal Fisheries Act regulate the quality of water discharged from the FFTIS. Saskatchewan Environment issues a permit to discharge water from the FFTIS.
REMINDER What steps must Hudbay take to demonstrate that the tailings pond is in compliance with provincial and/or federal regulations?
BRUBACHER: Legal requirements issued by the federal government and provinces of Manitoba and Saskatchewan apply to the FFTIS.
Both Manitoba and Saskatchewan govern the physical integrity of the FFTIS. Each will have its own reporting requirements to demonstrate compliance.
In 1993, a Joint Regulatory Group was formed. The JRG is comprised of members from Environment Canada, Manitoba Conservation, Manitoba Innovation, Energy and Mines, Manitoba Labour and Saskatchewan Ministry of Environment.
The planned annual construction on the FFTIS requires approval from Saskatchewan’s Ministry of Environment and from Manitoba’s mines inspector.
REMINDER What is the estimated remaining lifespan of the tailings pond?
BRUBACHER: Deposition plans, dam construction activities, and long-term dam stability requirements are planned to accommodate tailings production for the life of the Flin Flon Concentrator.
For additional background, in addition to regulatory and legal requirements, Hudbay is a member of the Mining Association of Canada (MAC) and we adhere to the Mining Association of Canada’s Towards Sustainable Mining protocols for managing tailings.
As noted, independent review panels oversee our tailings management design and practices in Flin Flon, in accordance with the TSM protocol.
MAC’s Towards Sustainable Mining Tailings Management Protocol requires mines to develop tailings management systems in conformance with these guides, and evaluate their performance against a series of indicators that are independently verified and publicly reported.
Hudbay tailings management system was last verified in 2012 through an independent external review.
Members of MAC have been required to measure their performance against these indicators since 2004 and have their mine site results published in our annual TSM Progress Report published on www.mining.ca every year in the fall. Verification of these results is required every third year.
