PERTH (miningweekly.com) – An expansion study at the Century zinc mine, in Queensland, has highlighted the potential for a mine life extension through to mid-2026, ASX-listed New Century Resources has reported.
New Century is currently undertaking a tailings operation at the mine, which started in August last year, and is ramping up to its initial Phase 1 design capacity of eight-million tonnes a year.
The expansion study considered three options for the Century mine, the first of which was continuing with the tailings operation, but increasing throughput to 12-million tonnes a year.
This will reduce total capital costs by 37% for the Phase 2 ramp-up, from A$63-million to A$40-million, with the capital use optimised to complete refurbishment of the remaining 45% of plant capacity to achieve the zinc recovery target, and a throughput rate of 12-million tonnes a year.
The capital spend to ramp up the tailings operation will be incurred over the 2020 financial year.
In the second case evaluated by the expansion study, New Century will spend an additional A$55-million to develop the South Block and East Fault Block deposits, while the third development case will require an additional A$97-million spend to develop all of the in-situ deposits.
Zinc production over the life-of-mine will reach some 233 000 t/y zinc-in-concentrate under the in-situ development options, based on a throughput of ten-million tonnes a year tailing and two-million tonnes a year in-situ, while lead production would reach 29 000 t/y lead-in-concentrate over the same period, with some 18.9-million ounces of silver also produced.
The in-situ development will also present New Century with an additional A$422-million in after-tax free cash flows, and A$268-million in overall net present value after tax estimates.
The combined in-situ and tailings operations have the potential to generate some A$1.5-billion in after tax free cash flow.
New Century on Tuesday said that an in-situ feasibility study was now under way and would be completed in the third quarter of the 2020 financial year. A decision to mine would be based on the results of this study.
Under the current schedule, New Century is planning to start its first concentrate production from in-situ mining by the second half of the 2021 financial year, should a decision to mine be taken.
In the meantime, the company is progressing the completion of the Phase 1 tailings ramp-up to rates of eight-million tonnes a year, and is planning to progress to rates of 12-million tonnes a year by the end of the third quarter of the 2020 financial year. The tailings operations would be ramped-down to 10-million tonnes a year with the start of in-situ operations.