"Following extensive due diligence, Northern Star was unable to agree mutually acceptable terms with Osisko," Northern Star managing director Stuart Tonkin said. 

"Northern Star is disciplined in its review of acquisition opportunities with superior shareholder returns being its first priority. We continue to view the Windfall project in an extremely positive light and wish Osisko well in its development of Windfall," he added. 

Osisko said it had decided independently developing the project would be optimal for its shareholders. 

"While joint-venture negotiations have concluded, Osisko maintains a mutually beneficial relationship with Northern Star as an important debt holder through its C$154 million in a convertible senior unsecured debenture due December 1, 2025, with interest at a rate of 4.75% per annum," Osisko noted. 

Canaccord Genuity Capital Markets analyst Kevin Mackenzie said that Osisko, with about US$200 million in cash, is still well placed to advance the project and a maiden feasibility study scheduled for this year should cast a better light on the project's economics. 

"While likely to be viewed as a disappointing outcome in the near term, we believe that Osisko remains well positioned to advance the Windfall project into production, given management's experience permitting, constructing, and operating the Canadian Malartic mine in Quebec, prior to selling it to Agnico Eagle and Yamana in 2014 for US$3.9 billion," Mackenzie said. 

"Overall, we expected the feasibility study will mark a sharp step change from the 2021 PEA, with a production profile potentially in excess of 300,000 ounce per year versus the 238,000oz/y outlined in the PEA," he added. 

Osisko's share price slumped 14% to C$4.13/share on the Toronto Stock Exchange on February 17. The company had a market capitalisation of C$1.43 billion. 

Northern Star closed trading at A$9.44/share on February 17, which was up from A$9.04/share the day prior. Northern Star's market capitalisation was A$10.99 billion.