AVZ Minerals Ltd.'s extended scoping study for 5 million tonnes per annum of capacity at the Manono lithium project in the Democratic Republic of the Congo outlined a pretax net present value of US$2.63 billion, at a 10% discount rate, with an internal rate of return greater than 64%.

Previously, the company outlined a net present value of US$1.6 billion, at a discount rate of 10%, and an internal rate of return greater than 90% in a 2018 scoping study, based on throughput of 2 million tonnes per annum.

Annual production will be about 1.1 million tonnes per annum, rather than 440,000 tonnes per annum, at a minimum of 5.8% lithium oxide, over a 20-year mine life.

Capex for the project is now estimated at US$380 million to US$400 million, up from the US$150 million to US$160 million range estimated earlier.

Meanwhile, operating costs are estimated at about US$323 per tonne, down from US$355 per tonne outlined previously.

The company said May 23 that this study includes the upgraded measured and indicated resources at the project's Roche Dure deposit, which grew 41.7% to 269.0 million tonnes at 1.65% lithium oxide, 816 parts per million tin and 36 ppm tantalum.

However, AVZ did not take into account the potential for tin byproducts, but plans to do so in a definitive feasibility study.