DRDGOLD Limited said its Ergo Mining (Pty) Limited subsidiary has begun reclamation of the 2.7 million ton (Mt) 4L25 mine dump, at a 3.8 million rand set-up cost.
The company said reclamation of this dump is integral to sustaining production at Ergo and would free up a considerable land patch.
The dump is within the 4A8 reclamation area, less than 5 kilometres (km) from Johannesburg’s central business district, near Ergo’s City Deep milling and pumping plant. With an average grade of 0.308 grams per ton (g/t), the 4L25 dump is estimated to contain some 850 kilograms (kg) of gold.
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DRDGOLD said 4L25 slimes will be recovered at a rate of up to 300 000 tons per month (tpm) over a period of 10 to 12 months, with supplemental tonnage coming from the 4L2 dump, reclamation of which is ramping down. This will sustain City Deep’s production levels for a further 12 months until the larger 4L3 and 4L4 reclamation sites begin, it added.
The 4L25 slimes will be reclaimed by a remote-controlled, high-pressure water gun positioned on top of the dump. It will be combined with 4L2 slimes, and then pumped via a 40 km pipeline to Ergo’s metallurgical plant at Brakpan for gold recovery.
Besides sustaining City Deep’s production for longer, 4L25’s reclamation forms part of the extensive land rehabilitation programme, DRDGOLD is executing under its “rolling back gold mining’s environmental legacy” banner. The partially reclaimed dump will now be removed completely to liberate some 37 hectares of land for rehabilitation and sustainable land use, the company said.
Further, remnant material from other clean-up sites will be reclaimed and trucked to the 4L25 site, and the newly installed pumping and piping infrastructure there will also relay this to the Brakpan plant for processing. Additional land will be cleared for rehabilitation and sustainable land use from this exercise.
DRDGOLD said it is in discussion with iProp (Pty) Ltd, the landowner, to ensure that the company’s redevelopment goal is achieved after its rehabilitation of the land is completed.
Established at Brakpan by Anglo American in the 1970s, Ergo was saved by DRDGOLD from complete dismantling, refurbished in several stages, and has gone on to clear hundreds of hectares of land sterilised by old mine dumps in the production of thousands of kilograms of gold that would otherwise likely never have been recovered. Years of additional value have been created for thousands of stakeholders.
In FY2020, Ergo had a 3.13 million ounce (Moz) reserve and a 7.79Moz resource. In the last reported period, the six months to December 31, 2020, Ergo retreated 11.3Mt with an average yield of 0.202 g/t to produce 2 269 kg of gold at a cash operating cost of 581 402 rand/kg. The average gold price received was 988 998 rand/kg, yielding a margin of more than 40%. In the period, 48.4 million rand was spent on rehabilitation at Ergo.
Contact the author at jon.hopkins@proactiveinvestors.com