The new 350 Return Air Raise (RAR) at Vale Canada’s Thompson Mine in Manitoba, Canada, is now up and running, marking a crucial milestone for the C$150 million Thompson Mine Extension Project (TMEP). The ventilation upgrade doubles available airflow to active areas of Thompson’s T3 mine and uses a silencer system to reduce noise.
TMEP will allow to the operation to extend current mining activities by 10 years. The initial C$150 million investment represents Phase 1 and includes critical infrastructure such as new ventilation raises, booster fans, a new sandfill plant, increased power distribution and an underground garage that will enable mining at lower depths and help strengthen the business case for Phase 2 investment. Phase 2 will include developing two new orebodies: Hangingwall High Grade and Hangingwall Deep. Aggressive exploration drilling holds the promise of mining well past 2040 and a total investment projected at more than C$1 billion.
Vale Canada operates two connected underground nickel mines, T1 and T3, collectively known as Thompson Mine. The project was required to remove the failing 345 RAR (which exhausts via two discharges) from service and construct the 350 RAR (which also exhausts via two discharges) to provide required additional ventilation capacity for the existing mining facilities at the Thompson Mine. There are now five Return Air Raises operating between T1 and T3. Each are paired with a corresponding fresh air raise, for a total of ten air raises.
Cementation Canada team at Vale’s Thompson mine with the Strata 950
Cementation Canada carried out the raising for 350 RAR using its own Strata 950 model of raise borer. These are the longest continuous raise bored pilot holes in the Americas at 3,529 ft, the first of which broke the previous record of 3,312 ft that was set in 2021. The project began in February 2022, and the breakthrough of the second raise to surface was completed on September 9, 2023, after a total of 587 days achieved with zero harm.
The overall project involved constructing twin 10 ft diameter raises with surface fans, variable frequency drives, and underground ventilation controls, as well as an associated electrical building (E-house), access road, and associated ditching and culverts around the 350 RAR fan station’s graded pad. Following construction and commissioning of the 350 RAR, 345 RAR is being removed from active service.