Osisko Mining (TSX: OSK) has released an updated resource estimate for its Windfall gold deposit in Quebec, which, according to CEO John Burzynski, “places Windfall among the best high-grade development projects globally.”
Measured and indicated tonnes now total 6 million tonnes at 9.6 g/t gold, for 1.9 million gold oz. and inferred resources add 16.4 million tonnes at 8 g/t gold, for an additional 4.2 million gold ounces across all categories now total 6.1 million oz.
When compared with the prior resource from February 2020, measured and indicated tonnes increased by 47%, alongside an increase in grade, which was previously 9.1 g/t gold. Similarly, inferred tonnes grew by 13% while the grades are now at 8 g/t gold, compared to 8.4 g/t previously. Cut-off grades are unchanged at 3.5 g/t gold.
The release notes that Osisko’s discovery and definition cost averages $38 per oz., with an average of 4.5 oz. of gold defined per metre drilled.
The high-grade Lynx zone makes up over 60% of the total ounces in the latest resource – Lynx grades average 11.3 g/t gold in the measured category, 11 g/t in the indicated subset and 9.9 g/t gold in the inferred classification. Lynx zones remain open down-plunge. Additional resources are contained in the Underdog and Main zones.
The Triple 8 zone is a new contributor, adding 655,000 inferred tonnes at 7.1 g/t gold.
“We are pleased to deliver this updated mineral resource estimate as Windfall continues to impress with increasing average grade and scale,” Burzynski said in a release. “We anticipate that by the end of the infill program and in the subsequent resource estimate, we will see another significant addition to the measured and indicated resource with increased grade, and further growth of the deposit scale.”
The CEO added that, since the cutoff for the resource, Osisko has received “strong infill results” not accounted for in this update. The latest numbers include drilling completed through to September and results received up to Nov. 30.
Since then, the company has drilled approximately 100,000 metres, with a further 200,000 metres expected to be completed by the third quarter. An updated resource would then be released after the infill program is complete. The remainder of the infill drilling will be focused on Lynx, with over 30 drills scheduled.
Additional drills are now targeting down-plunge extensions of Lynx and the nearby Fox trend, as well as targets along strike of Windfall. An exploration ramp is also advancing to extract the third bulk samples from the Triple Lynx zone. Osisko has received approvals to mine Lynx test stopes.
Earlier this month, the company closed a $70-million bought deal private placement of flow-through shares.
Exploration results from January include drill highlights of 10.5 metres of 108 g/t gold from Triple Lynx and 11.3 metres of 21.7 g/t gold from Lynx.
The Windfall deposit lies between Val-d’Or and Chibougamau in the Abitibi. The mineralization is made up of sub-vertical zones that follow northeast-plunging porphyry contacts. Current resources are defined from surface to a depth of 1,600 metres (to 1,200 metres excluding the T8 zone). The deposit remains open on strike and at depth; mineralization has been identified down to 2,625 metres.