True widths are estimated to be 60% to 75% of reported core length intervals. Intervals not recovered by drilling were assigned zero grade. Top cuts have not been applied to high grade assays.
A total of 10 diamond drill rigs are currently active on the project. Thus far in 2021, 41,000 metres have been drilled in 134 holes at Island Mountain, which encompasses both the Mosquito Creek and Shaft Zone deposits in the Cariboo project. The drill campaign is aimed at both exploration and upgrading existing resources.
Cariboo is Osisko Development’s flagship asset, with measured and indicated resources of 21.4 million tonnes grading 4.6 gold g/t for a total of 3.2 million oz. of gold and inferred resources of 21.7 million tonnes grading 3.9 gold g/t for a total of 2.7 million oz. of gold. The project is advancing through permitting as a 4,750-tonnes/day underground operation, with a feasibility study on track for completion in the second half of 2021. The company is testing the use of ore sorting technology at the project.
Mineralized quartz veins on Cariboo overall have a sub-vertical dip and northeast strike. A vein corridor is defined as a high-density network of mineralized quartz veins within the axis of the last folding event, and two vein corridors are hosted within a brittle meta-sandstone or calcareous meta-sandstone. Vein corridors are modelled at a minimum thickness of 2 metres and average about 4.5 metres true width. Individual mineralized veins within these corridors have widths varying from centimetres to several metres and strike lengths from a few metres to over 50 metres.
These corridors have been defined from surface to a vertical depth averaging 300 metres and remain open for expansion at depth and along strike. Gold grades are intimately associated with quartz vein-hosted pyrite as well as pyritic, intensely silicified wall rock haloes in close proximity to the veins.
(This article first appeared in the Canadian Mining Journal)
