A bench-scale dense media separation (DMS) test program was completed to assess the amenability of mineralized samples from the deposits to physical upgrading (pre-concentration) at each site. Use of DMS processing technology would provide a potential means of reducing transportation costs from the mine sites to the flotation concentrator and of maximizing head grade and reducing downstream processing costs. An economic assessment of processing ores using DMS technology is in progress to determine if there is a net benefit in reducing the mass of ore to be processed compared to the loss of payable metals to the waste product.

Preliminary bench-scale test results also confirmed that selective zinc, lead and copper concentrates can be produced at marketable grades using a common flotation flowsheet. The positive results from these tests support the development of sequential flotation technology and a flowsheet for processing of the deposits using a centralized processing facility.

The research project initially focused on four volcanogenic massive sulphide deposits on the south side of Red Indian Lake. Two of the deposits are held by Canadian Zinc, and two are held by Buchans. In June, the research program was extended to include Buchans’ Lundberg copper-lead-zinc-silver deposit on the north side of Red Indian Lake.

The metallurgical test programs are being followed up with development of a process simulation and cost assessment model to evaluate and identify the key factors impacting the operating economics of a centralized processing plant. The overall Canadian Zinc/Buchans research programs are being partially funded by the Research & Development Corporation of Newfoundland and Labrador through its industry-led GeoEXPLORE program.