Abstract:

Teck Resources Ltd.’s (Teck’s) Highland Valley Copper Mine is a major open-pit mine and mill operation located in the Interior Region of British Columbia, Canada. The mine produces both copper and molybdenum concentrates at a production rate of up to 165,000 tonnes per day. The Highland Tailings Facility is an active tailings facility which stores more than 1.5 Bt of tailings, retained by two dams: the L-L Dam, which is a 163 m high centreline cyclone sand dam; and the H-H Dam, which is a 94 m high centerline rock fill dam.

Teck and the Engineer of Record, Klohn Crippen Berger Ltd. (KCB), have implemented a robust surveillance program for the Highland TSF which is focused on proactive risk management, confirming design assumptions and supporting improved decisions on tailings management.

In 2019 Teck completed a review, with KCB, of the design for both dams and the operational plan for the Highland TSF. Review activities started with updates to the characterization of geology, failure modes, risk control, and a review of design basis. This was guided based on the principals of the Observational Method (Peck 1969) to utilize knowledge from the extensive operational history and performance records of the facility dating back more than 40 years.

This characterization work was also the basis for the surveillance plan updates at both the H-H Dam and the L-L Dam. Teck and KCB applied a comprehensive process to ensure surveillance activities were tailored to meet the requirements of key risk controls and to measure key dam behaviours which can be used to improve predictions of future behaviour and reduce residual uncertainty. These improvements have significantly increased the value gained from surveillance efforts, as well as providing Teck and KCB a basis to make informed assessments on the effectiveness of the surveillance plan and opportunities for further improvement.

This presentation will give an overview of some high-value changes made to the surveillance plan at the H-H Dam and at the L-L Dam, and how surveillance information is being incorporated into operational and closure decisions, specifically: implementing a contingency case design using the Observational Method; assessing how to incorporate new surveillance technologies and techniques; and, using measured performance to inform design and reduce uncertainties.

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Aaron Sangha