South Malartic posts new number for Croinor

A new resource figure suggests the Croinor gold deposit in Quebec’s Pershing Twp. is smaller and richer in grade than than previously thought.

The calculation, prepared by consulting firm Innovexplo for owners South Malartic Exploration (MSU-V), gives Croinor 1.4 million tonnes at an average grade of 6.3 grams gold per tonne, based on a 2-gram cutoff grade. Increasing the cutoff to 5 grams shrinks the tonnage to 620,000 tonnes, with an increase in grade to 10.4 grams per tonne.

A 2003 resource estimate put the size of Croinor at 2.5 million tonnes grading 3.5 grams gold in measured and indicated categories.

Some of the Croinor pit had been mined, with milling done by Richmont Mines‘ (RIC-T) Camflo mill in Val d’Or, 55 km to the west, but the mined material did not meet the grades projected in the resource model and mine plan. The 30,760 tonnes milled proved to have an average gold content of 2.2 grams per tonne, against a predicted grade of 5.5 grams. South Malartic then contracted Innovexplo to review grade control and dilution in the pit.

Subsequent test mining resulted in the extraction of 24,174 tonnes with an average grade, estimated from blastholes, of 6.2 grams per tonne. That material will be milled at Camflo in July.

The new resource is in 38 veins in the Croinor diorite intrusion. About 1.1 million tonnes grading 6.4 grams per tonne are classified as a “continuous resource.” Another 308,000 tonnes with an average grade of 6.3 grams per tonne are in isolated blocks, pierced by only one drill intersection that meets the estimate’s cutoff criteria. The company says it will need to drill those areas more tightly to define the shape and size of that part of the resource.

South Malartic is now considering whether it should commission a prefeasibility study on an underground operation. It is also looking for potential partners on the project.