Digging Deep: The Deepest
Mines in Canada

Engineering Notes

Mining at nearly 3 km depth required extraordinary ground control measures, including extensive use of shotcrete, cable bolts, and destress blasting to manage extreme seismic conditions. The ventilation system was among the most powerful in global mining, with multiple surface fans moving air through a vertical distance greater than the height of nine Eiffel Towers stacked end-to-end. Ore was hoisted in stages through multiple shaft systems.

Engineering Notes

Creighton's deep mining operations use a modified slot-and-slash method with pastefill for ground support. The mine's ventilation system moves over 1.5 million cubic feet of air per minute through 2.5 km of vertical infrastructure. Refrigeration plants reduce air temperatures from 45°C to workable conditions. The shaft system includes the legendary #9 shaft, one of the deepest single-lift mine shafts in Canada. Rock mechanics at this depth involve managing stress fields that can exceed 100 MPa, requiring specialized destress blasting protocols.

Engineering Notes

Mining at 2,400 metres requires industrial-scale refrigeration plants to cool intake air to 8°C before it descends to working levels. The mine uses a shaft system with two main hoists — the #3 and #4 shafts — plus a Ramp Access System (RAS) for mobile equipment. Seismicity monitoring is critical, with a dense network of geophones tracking micro-seismic events to predict and manage rockbursts. Ground support includes extensive use of dynamic rockbolts designed to absorb energy from sudden rock failures.

Engineering Notes

LaRonde operates one of the most powerful refrigeration systems of any Canadian mine, with multiple ice plants producing chilled water and ice slurry that is pumped underground to cool working areas. The mine uses a combination of shaft hoisting and internal ramp access. At its deepest levels, rock pressure causes "strain bursting," where small explosive failures of the rock face occur without warning, requiring miners to work behind protective screening. Agnico Eagle has developed proprietary monitoring systems to track ground conditions in real time.

Engineering Notes

The Odyssey shaft is being sunk to 1,800 metres using conventional shaft-sinking methods with ground freezing in the upper section to manage water-bearing formations. At depth, the mine will require full refrigeration and chilled-water cooling systems. The project leverages existing surface infrastructure from the Canadian Malartic open pit, including the 55,000-tonne-per-day mill, which significantly reduces capital costs. Ramp access currently provides early ore production from shallower zones while the shaft is being completed.

Engineering Notes

Coleman features a unique skip-loading system that handles multiple ore types separately, allowing Vale to blend feeds at surface. The mine's deepest workings require active ground support management due to the complex geology of the North Range, where the Sudbury meteorite impact created intensely folded and faulted rock structures.

Engineering Notes

The mine was designed from the outset for deep mining, with a 5,577-foot production shaft and 1,200-tonne-per-day hoisting capacity. An innovative ventilation design used raise-bored ventilation shafts to provide fresh air to deep working levels. The orebody's geometry required careful sequencing to manage stress redistribution as stopes were mined and backfilled.

Engineering Notes

Fraser's mining methods evolved over its life from conventional drill-and-blast to modern mechanized longhole stoping with pastefill. The mine's depth required managed sequences to control stress redistribution as adjacent stopes were extracted.