Thierry Copper and Nickel project is a past producing mine located in Ontario, Canada. (Credit: John Mortimore/ Wikipedia)
The project is owned by Canadian Critical Minerals. (Credit: Dariusz Sankowski from Pixabay)
A Preliminary Economic Assessment (PEA) of the Thierry Project was published in January 2021. (Credit: Khusen Rustamov from Pixabay)

Thierry Project is a past-producing mine copper and nickel mine located in Ontario, Canada. The project also contains palladium, silver, platinum and gold.

In December 2020, the property was bought by mining company Braveheart Resources with the intention to bring back the brownfield mine into production.

A Preliminary Economic Assessment (PEA) of the Thierry Project was published in January 2021. In April 2022, Braveheart completed an updated PEA for the project.

The total capital cost of the project is expected to be C$710.5m ($525m). The updated PEA indicates a 4,000 tonnes per day (tpd) underground mining and processing operation over 14 years.

In January 2023, Braveheart Resources changed its name to Canadian Critical Minerals (CCMI).

The company is focusing on exploration drilling at the property. In August 2023, it completed a summer exploration drilling programme which focused on expanding upon the adjacent K1-1 deposit.

Thierry Project Location Details

The Thierry Project is located around 15km west of Pickle Lake in Ontario. It includes 27 mining leases totalling an area of 4,670 hectares.

The project also has 163 contiguous cell claims and 15 boundary claims, which increases the combined property area to 7,907 hectares.

The mine can be accessed by an all-weather road. A municipal airport, nearby rail system and provincial power grid are located within 8km of the mine.

K1-1 near surface copper-nickel deposit is situated around 3km east of the Thierry Mine.

Geology and Mineralisation

The Thierry and K1-1 deposits lie along the northwest margin of the Pickle Lake Metavolcanic-Metasedimentary Belt.

The mine sequence comprises metamorphosed gabbro and ultrabasic rocks that are hosted by sequences of massive to pillowed mafic volcanic rocks. The intrusions were indicated as amphibolite, peridotite and metagabbro.

Mineralisation at the Thierry and K1-1 deposits is described as a chlorite-biotite-hornblende altered mylonitic shear zone.

The shear zone stretches across the ultramafic intrusive along a strike length of approximately 1km and a width of up to 50m.

The mineralisation within the shear zone occurs in highly schistose rocks containing stringer sulphides to less schistose ultramafic rocks containing large stringers or veins and disseminated sulphides.

The copper-nickel-platinum group elements mineralisation is found within a highly deformed and altered ultramafic sequence consisting of sulphide matrix breccia; blebs and small stringers, occasionally net textured sulphides; and disseminated sulphides.

Mineral Resource Estimate

According to the PEA, the mineral resource estimate for Thierry underground includes 8.8 million tonnes in measured and indicated categories at 1.66% Cu, 0.19% Ni, and 0.13 g/t Pd.

In the inferred category, the figure stands at 14.9 million tonnes at 1.64% Cu, 0.16% Ni and 0.21 g/t Pd.

The Mineral Resource Estimate for the K1-1 near-surface open pit deposit is 53.6 million tonnes in the inferred classification at 0.38% Cu, 0.10% Ni, and 0.14 g/t Pd.

Mining and Ore Processing                                           

A combination of underground sublevel retreat long-hole methods is expected to be used to mine at Thierry Deposit. The primary method will be the underground long-hole retreat method.

The deposit will be accessed by a 6.5m diameter, concrete lined 965m deep fresh air shaft and a -15% ramp from surface to a depth of 1,260m.

It will include two shaft loading pocket stations and two hoists to transport workers. The construction and other materials would be transported underground using a ramp from surface.

A total of 432 stopes are planned to be mined over the 14 years to generate an average of 4,000tpd of process plant feed.

On the other hand, open pit mining is expected to be economical for the K1-1 near surface, low grade polymetallic deposit.

The project will have a conventional process plant and a flowsheet. This will include crushing and grinding to a 100µm grind at a rate of 1.4 million tonnes per annum (Mtpa).

This would be followed by a two-product flotation circuit- a 30% copper concentrate containing low nickel and 50% of the PGM; and a nickel-copper concentrate containing 10% metal (8% Ni, 2% Cu) and low PGM.

The concentrates will be then transported to an off-site smelter.

The tailings will be thickened to 55% solids for mine paste backfill, while the remaining will be disposed of in the waste rock and tailings co-disposal facility (CDF).

Thierry Project Infrastructure

The past-producing Thierry underground mine includes approximately 40km of underground shafts, ramps, raises, and drifts. This infrastructure used to offer access to the upper workings of the mine.

The underground infrastructure is currently flooded.

The project’s key infrastructure will include an administration/safety/mine dry building, a shaft headframe and hoistroom/compressor building; a process plant; a paste backfill plant and distribution system; a tailings/waste rock co-disposal basin and dam.

Other facilities will include fuel, lubricant and oil storage facilities; a fire prevention and fighting system; potable water treatment plant and storage tanks; tailings water treatment plant and pond among others.

The overall site power consumption is estimated to be 16MW. An electrical power line and electrical substation will be built, and connected to the local grid for power supplies to the site.

Contractors Involved

P&E Mining Consultants prepared the independent NI 43-101 Technical Report and PEA of the Thierry deposit and the Mineral Resources of the K1-1 Deposit.

The updated PEA was also prepared by Ontario-based P&E Mining Consultants.