Orion Prieska
Orion Minerals' Prieska copper zinc project

Orion Minerals has announced that, following the successful conclusion of value engineering studies on the ore processing plant design and layouts for the Prieska Copper-Zinc Project, the company has moved to secure specific mills required to realise the identified improvements via an option agreement.

Orion Minerals has identified two new 3,600 kW mills, that are immediately available at a significant discount to similar mills which would only be available from manufacturers on long order.

Watch: Errol Smart discussing investment in South Africa

The mills consist of a 22-foot diameter x 26-foot long ball mill and a 16.5-foot diameter x 27-foot long semiautogenous grinding (SAG) mill, complete with all motors, gearboxes, ancillary fittings, with associated commissioning spares.

Securing these new mills facilitates the incorporation of SAG milling into the ore processing flowsheet, in place of the ball milling arrangement selected in the Prieska Project BFS.

The revised ball and SAG mill configuration will allow significant operational flexibility and facilitate processing of Prieska ore at a rate of up to 20% above design throughput, allowing capacity for future expansion.

The use of SAG milling simplifies plant layout and operation, with significantly reduced upfront capital expenditure and a reduction in estimated operating cost, removing the requirement for multi-stage crushing and screening of rock ahead of milling.

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Overall capital expenditure for the processing plant has been reduced by approximately AUD15 million from the total plant capital, originally estimated at AUD109 million and the plant unit operating costs reduced by 5% from a base estimate of AUD16.10 per tonne.

This represents a significant improvement to be incorporated into the optimised and updated BFS Report, due for completion in early Q2 CY2020.

“We are very pleased that we can now begin to lock in the anticipated project optimisations with associated positive CAPEX and OPEX savings,” says Errol Smart, Orion Minerals MD and CEO.

“The plant optimisation studies progressed alongside studies on improved water treatment and optimisation of our mine-to-market schedule, all of which are now nearing completion.

“The successful metallurgical optimisation of the process flowsheet has culminated in securing the right to purchase two new mills which are available at a significant discount to mills which would otherwise have to be placed on order as a long-lead item.

These optimisations all promise to deliver an uplift on the already excellent investment case for the Prieska Project.”