Positive metallurgy at Canadian Zinc’s Prairie Creek

Vancouver – Metallurgical testing of ore from Canadian Zinc’s (CZN-T) Prairie Creek zinc-lead-silver deposit, located in the MacKenzie Mountains of western Northwest Territories, has shown positive processing and recovery results.

Bulk samples of both oxide and sulphide vein material, extracted from underground workings, underwent bench-scale testing by SGS-Lakefield Research Laboratories, returning positive results.

The study examined the different ore types present at the planned mine, including the deeper, drill-extracted stratabound mineralization beneath the existing underground workings.

Use of a heavy-media gravity separation circuit showed a notable improvement in recoveries, with 31% of the sample weight removed as waste. Combining the oxide and sulphide ores as well as the vein-hosted and stratabound material did not impact metal recoveries, which are expected to be higher than previously predicted.

The concentrates produced in the tests also showed to be readily saleable and will be used by specific smelters to evaluate proposed Prairie Creek output.

Vein-hosted mineralization at the deposit is associated with the north-south-trending Prairie Creek fault, which has been traced for more than 10 km. A dozen separate, veined massive sulphide occurrences have been identified; these consist of quartz-vein systems heavily mineralized with lead, zinc, copper and silver. Underground development on various levels has proved the continuity of one vein along at least 940 metres of strike, and drilling indicates a further 1.2 km of continuation. The vein system remains open northward and at depth.

In the early-1990s, a second type of mineralization was discovered at Prairie Creek: stratabound- or stratiform-type, which generally occurs between depths of 300 and 500 metres below surface. The stratiform massive sulphides parallel bedding and contain zinc, lead and iron sulphides with some silver and minor copper.

Canadian Zinc’s predecessor company, San Andreas Resources, acquired an option on the project in 1991, and then carried out extensive drilling and rehabilitation of underground workings. In 1998, an independent resource calculation on Zone 3 indicated a geological resource of 11.8 million tonnes grading 12.5% zinc, 10.1% lead and 161 grams silver.

A scoping study in 2001 suggested that the operation could be brought to production at a capital cost of about $40-million. Annual output was pegged at 95 million lbs. zinc plus byproduct lead and copper concentrates containing significant silver. The project has the benefit of having $100 million worth of mine development, mill and infrastructure already in place from previous owners.