Bulk sample processing results from Osisko Mining’s Windfall Lake project came in ahead of company expectations with average head grades of 17.8 g/t gold exceeding the 9.4 g/t predicted by infill drilling.
“The significant grade increase from the block model appears to correspond well with the very regular visible gold observed in Lynx drilling. The bulk sampling work is greatly helping to build our confidence in the continuity, grade, recoveries and the predictability of the mineralized zones at Windfall,” John Burzynski, Osisko Mining president and CEO said in the media release.
A 5,716 tonne bulk sample was extracted from the Lynx zone 311 through longhole mining. A total of 3,181 oz. of gold and 2,052 oz. of silver were recovered from the sample based on reconciled recoveries of 97.2% and 94.3% for gold and silver respectively.
The material was processed in November by a third party with the resulting gravity and flotation concentrates sent to a smelter for sale. Gold recovery to the gravity concentrate was at 66.7%.
The unit host to the bulk sample material is approximately 2.5 metres wide and has been mapped over three levels.
Given the positive recovery numbers, Osisko plans on additional work on the process flowsheet before advancing to feasibility level studies.
Current Windfall indicated resources stand at 2.9 million tonnes at 8.17 g/t gold for a total of 754,000 oz. with additional inferred resources of 10.4 million tonnes grading 7.11 g/t gold for 2.4 million oz.
These resource numbers exclude the Windfall North, Lynx Extension and Triple Lynx zones discovered in 2019. Mineralization remains open at depth.
The Lynx Extension and Triple Lynx zones have returned high grades during infill and expansion drilling completed earlier this year, including an intercept of 13 metres at 106 g/t gold from the Lynx Extension.
A resource update for Windfall is expected in February of next year, to be followed by a feasibility study.
There are 21 drills are currently working on the Lynx and Triple Lynx zones with another three working on other areas at the project.
Earlier this month, the company closed a C$61 million bought deal private placement of flow through shares.
(This article first appeared in the Canadian Mining Journal)
