The mineral reserve at TSX-listed First Quantum Minerals' Kansanshi mine, in Zambia, has increased by 70% to an estimated 842-million tonnes, grading 0.64% copper, while the mine's mineral resource has increased by 40% to an estimated 939-million tonnes, grading 0.67% copper.

This compares with estimates published in 2015 and follows 1.5-million metres of resource expansion drilling.

These results have extended the Kansanshi mine life to 24 years.

Further, the increased reserve forms the foundation for a potential restart of the S3 Expansion, which will increase the mine's sulphide, mixed and leach ore processing facilities' capacity to 52-million tonnes a year, from the current 28-million tonnes a year.

The expansion project has an estimated total capital cost of $650-million for construction, as well as enhancements to existing infrastructure. This includes an estimated $408-million for construction of the facilities and about $242-million for the procurement of additional mining fleet to increase mining volumes from 50-million bank cubic metres to 80-million bank cubic metres.

The S3 Expansion was previously approved and the earthworks, foundations, steelworks and filtration facilities were completed before activities were halted in 2013 as a result of market conditions and a challenging fiscal environment.

First Quantum intends to further refine the expansion plan before seeking project approval, which it expects to do in the next two years.

Once internal approvals are granted, construction could potentially restart in 2023, with the project to be completed in late 2024.

First Quantum is, meanwhile, also planning to increase the capacity of the Kansanshi smelter to 1.65-million tonnes a year during 2022/23, from the current 1.38-million tonnes.

The company explains that it will not build a second smelter as initially proposed. Rather, the capacity increase will be achieved through enhancing copper concentrate grades by lowering the carbon and pyrite content of the Kansanshi and Sentinel concentrate feeds.

Concentrate processing capacity will be further expanded through modifications to the existing high-pressure leach (HPL) circuit.

First Quantum expects to spend about $80-million on the smelter expansion and $15-million on the concentrate cleaning and HPL circuit modifications.