JOHANNESBURG (miningweekly.com) – DRDGOLD is excited about the up-flow reactor, which is showing good promise, DRDGOLD CEO Niël Pretorius responded when questioned by Mining Weekly on the Johannesburg Stock Exchange-listed company’s modernisation moves.

The use of an up-flow reactor (UFR) to improve recoveries forms part of DRDGOLD’s Far West Gold Recoveries DP 2 plant, the smelt house of which was commissioned on July 14. The balance of the DP2 plant is expected to be commissioned during the current quarter.

An up-flow reactor used to recover gold is described as being a specialised vessel that pumps gold-bearing slurry or chemical solution upward through a vertical chamber to suspend solid particles without mechanical stirring. This counter-current flow system is said to improve gold recovery rates, accelerate reaction kinetics, and cut cyanide consumption by optimising the interaction between gold particles, leaching reagents, and activated carbon.

DRDGOLD did some testwork, liked what it saw, took a recommendation to the board and has been given the go-ahead to build an Aztec up-flow reactor.

“This is frontier stuff for us, so whilst we’re very happy with the pilot work, which was not laboratory-scale testwork but proper pilot plant testwork, this technology has not been tested in real-world conditions and we’ll only know what the contribution of the up-flow reactor will be once we see it.

“So, we're not updating any of our forecasts or any of our guidance in terms of what we believe this reactor will deliver until we've seen real-world numbers.

“It's an important development, though, and we hope that it lives up to expectations,” Pretorius explained.

Once the gold-bearing material has gone through the carbon-in-leach plant, it goes into the up-flow reactor.

FIVE PROJECT ADVANCE

Of the five projects that make up DRDGOLD’s Vision 2028, two are at Ergo on the East Rand and three are at Far West Gold Recoveries (FWGR) on the West Rand. (Also watch attached Creamer Media video.)

Vision 2028 is DRDGOLD’s approximately R10-billion programme to increase combined throughput at Ergo and FWGR, lift annual gold production towards six tonnes by 2028 and extend FWGR’s life-of-mine. More than R5-billion has now been invested.

The first one is Daggafontein, a tailings storage facility (TSF) which has been commissioned at an estimated cost of about half-a-billion rand to reduce the deposition rate onto the Brakpan TSF by about 750 000 t a month.

The second one at Ergo is the R3-billion Withok tailings dam, which is still in the authorisation phase. Withok’s purpose is to enable DRDGOLD to exit the Brakpan TSF in totality and to then maintain the deposition capacity for the Ergo operations.

The three projects at FWGR are actually one project with three different legs.

The first leg, the DP2 plant expansion, involves doubling up the existing 600 000 t capacity to 1.2-million tons.

The second leg involves 135 km pipeline network for DP2 to the big Regional Tailings Storage Facility (RTSF) deposition site, as well as the Libanon reclamation station at a cost of R1.2-billion.

The third leg is the RTSF itself, which is an 800-million-ton facility, making it one of the world’s largest tailings dams constructed on a mine.

Roughly two-thirds of this facility has been constructed at a cost of about R3.4-billion.

DAGGAFONTEIN

Commissioning of the Daggafontein TSF began in June and the expected 25 000 t a day to achieve 750 000 t a month is being met. Daggafontein is providing additional deposition capacity of about 120-million tons. With Withok, it will sustain the mining operation for 21 years at Ergo.

The public participation process for Withok has been completed and DRDGOLD’s design engineer and his team have been approved by the dam safety office.

The environmental authorisation and waste management licence, as well as the water use licencec has been submitted to the department, and approval is awaited.

“We hope to obtain these approvals by the end of this year,” DRDGOLD COO Jaco Schoeman reported in the presentation covered by Mining Weekly.

If that can be achieved, the aim will be to complete the construction of Withok in 2029, taking deposition capacity to 310-million tons. Together they provide a 21-year mine life.

At FWGR, DP2’s smelt house was commissioned on July 14 and the smelter’s first gold bar poured.

The balance of the DP2 plant is expected to be commissioned during the current quarter but it may not mean immediately going up to the 1.2-million tons of material.

The intention is to commission this plant, move over to it, operate it, and then to refurbish the old plant.

Once RTSF is ready to take the full 1.2-million tons, both plants will be fired up.

The 500 000-t-a-month throughput capacity will be maintained until the RTSF is ready, Schoeman pointed out. It is hoped that this will be  available in the first quarter of DRDGOLD’s 2028 financial year.

“We are aiming to achieve beneficial occupation a lot sooner, but depending on what the weather does and how it rains, we will then make an informed decision before we start up that facility in all earnest,” Schoeman explained.