Centrex Metals Ltd. on Oct. 8 announced that a definitive feasibility study for the Ardmore phosphate project in Queensland, Australia, pegged a posttax unleveraged net present value, discounted at 10%, of A$109 million, an internal rate of return of 30% and a four-year payback period.

The feasibility study is based on a 10-year open pit operation producing 800,000 wet tonnes of phosphate rock concentrate per year, assuming a CFR sales price of A$211/t. The study results were based on a maiden ore reserve for the project, which holds an estimated 10.1 million tonnes grading 30.2% phosphorus pentoxide in the proven and probable categories.

Centrex updated Ardmore's mineral resource estimate in June.

Preproduction CapEx is projected at A$76.6 million with sustaining CapEx coming in at A$11.5 million. The Australian explorer expects to source the project's financing through a combination of equity and debt funding with cash on hand sufficient to progress early works on the start-up phase, scheduled for mid-2019.

Life of mine CFR operating costs, excluding royalties, was estimated at A$149/t.

Mining and processing operations are scheduled to start in the first half of 2019. Approvals for the operations and long-term off-take deals with customers are due in the second half of 2019.

Construction will begin in 2020, with first production following in 12 to 15 months. Full-scale mining is targeted in the first half of 2021 due to a shallow orebody and the plant being de-risked during the start-up phase. A final investment decision is scheduled for the end of 2019.

In January, a scoping study for Ardmore estimated a pretax net present value, discounted at 10%, of approximately A$124 million to A$129 million, an internal rate of return of 39% to 42% and a three-year payback.