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TAILINGS MANAGEMENT AT THE IRON MINE OF MOUNT WRIGHT

Session: Uncertainty, Reliability, and Risk / Incertitude, fiabilité, et risque

Frédéric Choquet, Amec Foster Wheeler (Canada)
David Bédard, Amec Foster Wheeler (Canada)
Desheng Deng, Amec Foster Wheeler (Canada)
Claude Bédard, Amec Foster Wheeler (Canada)
Serge Thériault, ArcelorMittal Mining Canada (Canada)
Sébastien Moreau, ArcelorMittal Mining Canada (Canada)

The tailings storage facility (TSF) of the Mount Wright mine, a property of ArcelorMittal Mining Canada, has been active since 1976. It is located in the Fermont area and spreads across 15 km² which makes it one of the largest impoundments in North America.

This paper discusses the choice of the appropriate raising method at the TSF and introduces the systems implemented to monitor the structures.

During winter, both coarse and fine tailings are mixed and pumped into the impoundment.

In summer, the fine tailings are redirected towards the north edge of the impoundment. Meanwhile, the coarse tailings are deposited with a patented system that allows the coarsest particles to decant and settle more quickly along the dam to be raised. This system creates beaches with steeper slopes and higher crests than with a traditional spigot system. The beaches are then used as borrow pits in order to elevate the crests further.

In order to ensure the safety of the retaining dams and dykes, many of them are equipped with various instruments, as detailed later in this paper. The analysis of the data constitutes an excellent tool to monitor the behaviour of the structures and illustrates their evolution through time.