Osisko, Gold Fields go 50:50 on Windfall gold development 

Osisko Mining (TSX: OSK) and a subsidiary of Gold Fields (NYSE:GFI; JSE:GFI) are creating a 50:50 joint venture for development of Osisko’s Windfall gold project, located in the Abitibi greenstone belt, Eeyou Istchee James Bay, Que.  

Gold Fields will make an initial cash payment to Osisko of $300 million and a deferred payment of another $300 million when the project is fully permitted. Two separate $17-million payments will be made to Osisko, one on July 1 and the second on Dec. 31, 2023. Gold Fields has also agreed to fund up to $75 million on regional exploration, after which such programs would be equally funded by both companies. 

Assuming the project is ultimately permitted and approved as outlined in the Windfall feasibility study, Gold Fields’ acquisition cost, exploration commitment, and contribution to pre-construction and project capital would ultimately represent an investment of $1.2 billion. 

The Windfall project site covers 12,523 hectares, 200 km northeast of Val d’Or and 115 km east of Lebel-sur-Quevillon, Que., within the traditional territory of the Waswanipi Cree First Nation. 

In November 2022, Osisko delivered a feasibility study for Windfall that included measured and indicated resources of 11.1 billion tonnes grading 11.4 g/t gold (4.1 million oz. of contained gold) as well as an inferred resource of 12.3 billion tonnes at 8.4 g/t gold (3.3 million oz.). Within the M+I portion are 12.2 million tonnes of probable reserves grading 8.06 g/t gold (3.2 million oz.) 

Resources and reserves are contained in several zones and in stockpiles. Zone 27, the Lynx zone, and Triple Lynx zones have all been reconciled by bulk sampling with positive results of, respectively, 26%, 89%, and 69%. 

The Windfall mine will produce an average of 305,000 oz. of gold each year over the 10-year life of the mine. All-in sustaining costs will be US$758 per oz. Underground mining will take place at a rate of 3,400 t/d and the processing plant will be sized accordingly. Commissioning of the project could take place by the end of 2025. 

Osisko chairman and CEO John Burzynski said in announcing the partnership, "We are very pleased to partner with Gold Fields on the Windfall project and our exploration property portfolio. Today is the start of what we believe will prove to be a long and fruitful partnership with Gold Fields at Windfall, and in what we both believe is a significant emerging gold district in Quebec.” 

More information about the Windfall gold project can be found on www.OsiskoMining.com.