How integrated expertise turned one of northeastern BC’s most complex legacy tailings sites into a cornerstone of the Quintette Mine restart
When Conuma Resources committed to bringing the Quintette Mine back to life after more than two decades on care and maintenance, they weren’t starting with a blank slate. The landscape around the mine site near Tumbler Ridge, British Columbia carries the marks of a previous era of production — including the Shikano North Tailings Facility, a legacy impoundment that needed to be thoroughly understood, assessed, and managed before modern operations could responsibly begin.
That understanding required more than standard due diligence. It required a team capable of bridging geotechnical rigour with environmental intelligence — one that could speak the language of dam safety and ecological stewardship in the same sentence. Conuma found that team in PRI.
A Mine with a Second Act — and Significant Responsibility
The Quintette Mine opened in 1982 and operated for nearly two decades before closing in 2000 when coal prices made continued production unviable. When Conuma Resources acquired the site from Teck in 2023 and secured permits to restart operations, the scope of what they were taking on became clear: not just restarting a mine, but inheriting a complex legacy footprint that had been sitting under BC’s environmental and regulatory watchfulness for over twenty years.
The Shikano North Tailings Facility is central to that legacy and to the mine’s operational future. Under Conuma’s restart plans, the Shikano Pit — now flooded — and the Shikano North Tailings Facility serve as a primary source of process water for the coal processing plant. That dual role — legacy structure and active operational asset — means the facility needed to be in a demonstrably sound condition before the mine could move forward with confidence.
That’s where PRI’s integrated scope of work began.
Geotechnical Excellence: Reading the Dam, Not Just Inspecting It
Tailings facilities are among the most geotechnically complex structures in mining. Unlike conventional earthworks, they are built incrementally over years or decades, constructed from the very material they contain, and subject to the cumulative effects of seepage, settlement, and pore pressure changes that evolve long after active deposition ceases. A legacy facility that has been dormant for over two decades presents its own specific set of conditions to assess.
PRI’s geotechnical scope at Shikano North went well beyond a visual walk-around. Working within the framework of BC’s Dam Safety Regulation and the Mine Review requirements associated with Conuma’s permit amendment application, PRI’s team conducted a detailed evaluation of the facility’s structural condition and long-term stability.
The work encompassed slope stability analysis — assessing the factor of safety of the embankment under static, seismic, and post-liquefaction loading scenarios. In northeastern BC’s seismically active environment, this is not a perfunctory calculation. It requires careful characterization of the embankment materials and their behaviour under dynamic loading, informed by both historical records and current field observations.
PRI’s assessment also addressed seepage and internal erosion potential — the mechanisms most commonly implicated in tailings dam failures globally. By evaluating drainage conditions, phreatic surface levels, and the integrity of internal drainage features, PRI provided Conuma with a clear picture of how water was moving through and beneath the facility, and what that meant for its long-term performance.
One of PRI’s most valuable contributions was the integration of instrumentation review and monitoring recommendations into the geotechnical assessment. For a facility being brought back into active service after years of dormancy, understanding what instruments were functioning, which needed replacement, and what new monitoring was required to meet modern dam safety standards was essential for responsible ongoing management.
The outcome was a geotechnical characterisation that gave Conuma — and the regulators reviewing their permit application — confidence that the Shikano North facility was structurally sound and could be safely integrated into active operations.
Environmental Services: Closing the Loop on Liability
The geotechnical story is only half of what makes PRI’s work at Shikano North significant. Legacy tailings facilities in BC’s coal belt carry a specific set of environmental considerations, and the Quintette Mine restart demanded that these be addressed head-on as part of the permitting process.
PRI’s environmental scope was designed to characterize the current baseline conditions at and around the facility and to support Conuma’s obligations under the Environmental Management Act permit amendments being sought alongside the Mines Act permit changes.
Water quality sits at the heart of tailings facility environmental assessment in British Columbia. The Shikano North facility’s water — and its interaction with the surrounding watershed — needed to be carefully characterised. PRI conducted surface water and groundwater quality assessment to establish baseline conditions, evaluate the potential for contaminant migration, and inform Conuma’s water management planning.
This work was conducted in the context of Conuma’s broader commitment to watershed-level water management — an approach the company has embedded across all of its operations. Conuma’s environmental program includes continuous monitoring of water quality and regional studies on selenium bioaccumulation to protect aquatic ecosystems. PRI’s site-specific work at Shikano North fed directly into that broader framework, providing the granular, facility-level data that makes watershed-scale management meaningful.
Beyond water, PRI’s environmental scope addressed vegetation and habitat conditions within and adjacent to the tailings facility footprint. Understanding what ecological recovery had occurred during the dormancy period, and what disturbance the restart would introduce, provided essential input to Conuma’s environmental management planning and regulatory submissions.
PRI also supported the development of monitoring plans — setting out the environmental indicators to be tracked, the sampling frequencies required, and the thresholds that would trigger adaptive management responses. This forward-looking component of the scope is what distinguishes a one-time assessment from an ongoing environmental management asset. Conuma now holds not just a snapshot of conditions, but a framework for staying ahead of them.
The Integrated Advantage
What made PRI’s contribution to the Shikano North work genuinely distinctive was the integration of geotechnical and environmental expertise within a single, coordinated scope.
These two disciplines are too often treated as parallel workstreams — the geotech team assessing the dam, the environmental team sampling the water, with findings reconciled after the fact. At Shikano North, PRI brought them together from the outset. Seepage pathways identified in the geotechnical assessment informed the location and priorities of the groundwater monitoring network. Slope stability findings shaped the reclamation and revegetation planning. The dam safety monitoring recommendations and the environmental monitoring framework were designed to complement each other, reducing duplication and ensuring that the facility’s management going forward is coherent rather than fragmented.
This integration reflects PRI’s multidisciplinary identity — a firm that has built its practice on the recognition that ground conditions and environmental conditions are not separate realities. They interact constantly, and engineering that accounts for that interaction produces better outcomes than engineering that doesn’t.
Supporting a Broader Regional Story
The Quintette Mine restart is a significant economic event for the South Peace region of northeastern BC. Conuma’s investment — upwards of $500 million to bring the mine back to full production — supports more than 400 permanent jobs and a much larger network of indirect economic activity centred on the communities of Tumbler Ridge and Chetwynd.
Getting the regulatory foundations right — including the environmental and geotechnical work at legacy facilities like Shikano North — was a prerequisite for that investment to proceed. PRI’s work helped clear that path: providing Conuma with the technical evidence base needed to support its permit amendment application, and providing regulators with the assurance that legacy infrastructure was being managed responsibly.
That contribution may not carry the same visibility as a new piece of mining infrastructure, but its importance to the project’s viability is hard to overstate. Responsible mining starts at the ground level — sometimes literally — and PRI’s work at Shikano North is a clear example of what that looks like in practice.
What the Shikano North Scope Demonstrates
Legacy tailings facilities represent one of the mining industry’s most pressing long-term challenges. As mines change hands, restart after dormancy periods, or seek to expand under new regulatory frameworks, the geotechnical and environmental histories of existing impoundments come under renewed scrutiny.
PRI’s work at Conuma’s Shikano North Tailings Facility demonstrates what effective engagement with that challenge looks like:
A geotechnical assessment that goes beyond compliance and delivers genuine structural understanding. An environmental scope that establishes rigorous baselines and sets up adaptive management for the future. Integration of both disciplines into a coherent picture that serves the client, the regulators, and the surrounding environment. And field expertise delivered by a team that understands British Columbia’s unique combination of terrain, climate, seismic conditions, and regulatory environment.
The Quintette Mine is producing steelmaking coal again. The communities around Tumbler Ridge are seeing economic momentum return. And beneath it all, the Shikano North Tailings Facility is being managed with the care and rigour that a responsible restart demands.