Mining company Rosh Pinah Zinc (RPZ) and investment adviser Appian Capital Advisory have announced the commissioning of the new semi-autogenous grinding (SAG) mill at the miner’s underground zinc/lead mine, in south-western Namibia.

Replacing the existing ball mill, the SAG mill is the final major processing component of the RP2.0 expansion project.

It will double RPZ’s processing throughput to 1.4-million tonnes of ore a year following mine ramp-up, delivering a step-change in yearly zinc and lead concentrate production.

The mill’s commissioning brings the full RP2.0 circuit into operation as an integrated system, incorporating the paste fill and water treatment plants and expanded flotation, thickening and filtration capacity.

The revised flowsheet is said to enhance comminution efficiency and resilience, delivering improved grind size control and metallurgical recovery while lowering unit operating costs.

Ore is crushed to a coarser product size ahead of the SAG mill, reducing dust generation throughout the crushing circuit and improving working conditions, environmental performance and on-site materials handling.

The SAG mill increases RPZ’s processing capacity and enhances the plant’s ability to treat harder ore types, which become more prevalent as mining progresses.

Moreover, the SAG mill has been designed with excess capacity, providing the potential for future production increases.

The expanded processing capacity extends the operation’s economic life and improves resource use across the orebody, strengthening RPZ as a long-life base metals project in Namibia.

RP2.0 comprises further development of the underground mine, including the newly developed WF3 portal and decline, as well as the construction of new surface facilities.

The project continues to advance on schedule and on budget, with overall construction progress now surpassing 95%.

The project has been executed with over two-million lost-time injury-free hours to date.

“Commissioning the SAG mill marks the completion of our core processing infrastructure and reflects the quality of execution by the RPZ team throughout the RP2.0 programme,” says Appian base metals head Ignacio Bustamante.

“With the full circuit now operational, the project is positioned to achieve a step-change in production output. This milestone demonstrates Appian and RPZ’s commitment to value-accretive, operationally rigorous project delivery and we look forward to realising the full benefits of RP2.0 as throughput ramps up,” he adds.