Blanket Mine builds new oxygen plant to raise gold recoveries

Caledonia Zimbabwe
Caledonia looking to expand beyond Blanket Mine

Caledonia Mining Corporation Plc says it has commissioned a new US$1.6 million oxygen plant at the Blanket Mine that will improve recoveries and cut the amount of cyanide used by the mine.

Based on test work conducted, the company said in a notice, it is anticipated that the plant will improve overall metallurgical recoveries at Blanket to approximately 94%. Recoveries – the amount of gold that a mine can extract from ore – have averaged approximately 93% in 2019, says Caledonia.

Steve Curtis, CEO of Caledonia, said: “We are pleased to have successfully commissioned the new oxygen plant at Blanket and look forward to improved operating efficiencies as a result. This marks the latest in a series of investments to increase production and improve operating proficiency at Blanket as we continue our growth trajectory to 80,000 ounces per annum by 2022.”

The new oxygen plant will provide up to six tonnes of improved oxygen supply to the Blanket Carbon-in-Leach plant.

“We also anticipate that the oxygen plant will result in slightly lower operating costs as cyanide consumption is expected to be reduced as a result of the improved oxygen supply; and the operating costs of the new oxygen plant are predicted to be lower than those of the previous two tonne plant,” Curtis said.

The company has been focusing on achieving a higher recovered grade. The company has seen lower grade due to dilution.

Caledonia has recently had to downgrade its guidance on annual production to account for lower-than-expected grade. Production guidance for 2019 has been cut to between 50,000 and 53,000 ounces, down from previous forecasts of 53,000 to 56,000 ounces. 

In August, Caledonia announced it had completed sinking of the new central shaft at Blanket, part of the London and New York-listed firm’s plan to ramp up gold production.

The project has been in progress since early 2015 and the company says it has spent US$44 million sinking the new shaft from surface to a depth of over 1,200 meters.

The shaft-sinking project has now moved to the equipping phase prior to commissioning, which is expected during the third quarter in 2020, Caledonia said in a statement. Production from Blanket mine is then expected to progressively increase to the target of 80,000 ounces of gold per year from 2022 onwards.