Wardrop Engineering is continuing to update and revise feasibility engineering work and costs for the Redfern Resources Tulsequah zinc-copper-silver-gold project in British Columbia, Canada. Work has been underway since early May and is expected to be finalized by year end. The scope of the feasibility study has been expanded to include an evaluation of the use of a Heavy Media Separation Process. This evaluation will assess the potential for rejection of lower density waste material from run-of-mine ore in order to upgrade the mill feed prior to the main grinding circuit. If successful and found to be cost-effective, the process may also allow the company to consider mining sections of the ore body narrower than the current 4-m thickness cutoff and/or use lower cost mining techniques to improve economics in narrower parts of the orebody. Samples of ore and adjacent hanging wall and footwall waste rocks were collected in June from the Tulsequah Chief deposit and have been received by the laboratory. The laboratory work is being conducted by Process Research Associates, under the supervision of Wardrop Engineering.
A separate metallurgical optimization test programme is also in preparation. The study will examine opportunities for enhanced separation of copper and lead minerals in the milling and flotation process. A reduction of lead content in the copper concentrate will improve marketability and reduce smelter treatment charges, thereby producing a potentially higher Net Smelter Return. In addition, the study will also evaluate the potential benefits of a process change to the zinc and pyrite differential flotation. The work will examine the benefits of bulk flotation followed by zinc/pyrite flotation separation. Changing the milling process flowsheet could have the benefit of a reduction in the consumption of reagents, thus reducing operating costs.
Wardrop’s engineers have a preliminary mine layout and are estimating costs for a mine development plan and a stoping plan. In general, the mine will be exploited from the existing 5400 and 5200 foot levels, moving in a downward direction. Where the overall plan permits, higher grade ore will be mined earlier in the life of the mine to improve cash flow. Mine layout and planning work is now more than 30% complete.