Cyprium Starts Acid Leaching as Nifty Copper Restart Enters Final Stage

Acid Returns to Nifty’s Heap Leach Pads

Cyprium Metals Limited (ASX:CYM) has started commissioning Nifty’s existing heap leach pads with sulphuric acid, marking the first acid application since operations ceased in 2009. It is the clearest sign yet that the company’s Phase 1 Cathode Restart project has moved beyond refurbishment and into the process of making copper-rich solution.

The company says acidified intermediate liquor solution is being transported from the eastern pond system into the heaps, while the ponds, acid transport infrastructure and associated pumping systems are commissioned. Cyprium says enough copper-rich solution has already been accumulated to support startup of the solvent extraction and electrowinning plant.

Direct Injection Trial Opens Larger Leach Inventory

A 14-well direct injection trial provided the technical foundation for the restart. Using water rather than acid, the trial tested the heaps’ hydrostatic behaviour, pressure response and wet and dry starts. Cyprium says the existing heaps accepted injected solution at commercial flow rates of about 250 cubic metres per hour and beyond, while the resulting outflows contained enough copper, at sufficient grade and quantity, to commission the SX-EW plant.

The wellfield has since expanded from 14 trial wells to 98 production wells, giving access to about 1.7 million tonnes of material for future leaching. Additional wells may be installed as production plans develop. The company says direct injection could access pad material more quickly and at lower cost than traditional surface leaching, although that remains an operational expectation rather than an achieved production result.

SX-EW Plant Nears Energisation

The SX plant is substantially mechanically complete and has entered dry commissioning and water-based commissioning. Pipework, tank repairs, pumps, compressors and firewater systems have largely been completed, with remaining work focused on installation, testing and commissioning across the plant.

The electrowinning plant is also substantially mechanically complete. Remaining tasks include finishing cell-top equipment, refurbishing the stripping machine, loading cathodes and anodes, and closing out electrical and instrumentation work. The rectiformer and transformer have been installed, along with high-voltage cabling and busbars linking the power system to electrowinning.

Electrical Faults Leave Commissioning Work Ahead

The path to first production is not entirely clear. Existing high-voltage components failed during testing, forcing Cyprium to procure replacement parts. The company says it has protected the schedule by using auxiliary power for pre-commissioning tasks such as motor testing and pressurising pipes and valves, but electrical, instrumentation and earthing work remains a key focus before safe energisation.

Cyprium now expects first cathode production in the fourth quarter of 2026 during wet commissioning and ramp-up. That is an expectation, not achieved output, and the announcement does not provide a production rate, project cost, funding position or revenue forecast for the restart.

Expansion Case Depends on More Leachable Material

Beyond Phase 1, Cyprium is preparing capital estimates and planning work for an SX-EW expansion from the targeted capacity of about 6,000 tonnes per annum to about 20,000 tonnes per annum. The larger plant would require more copper feed, potentially from faster access to the existing heaps, surface stockpiles or shallow oxide material in the open pit.

The company is also evaluating that shallow oxide inventory, refining plans for open-pit sulphides and concentrator refurbishment, and continuing exploration at Nifty, Rainbow and Rainbow South. Updated Mineral Resources and Ore Reserves are expected in the second half of 2026, while Rainbow assay results have been delayed after conflicting information emerged during quality-control checks and samples were sent for reprocessing. The immediate test, however, is more prosaic: whether the newly energised plant can turn copper-rich solution into its first saleable cathode.