Tag Archives: DRDGOLD

DRDGOLD’s Ergo and Wits University researchers to assess alternative leaching tech

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DRDGOLD Ltd’s flagship metallurgical plant, Ergo Mining Proprietary Limited, has entered into a second five-year (2022-2026) research and support agreement with the University of the Witswatersrand (Wits University) through the Gold Research Group in the School of Chemical and Metallurgical Engineering. The agreement will see continuation of research with the objective of enhancing capacity and capability within the field.

The research, DRDGOLD says, will seek to allow for more effective optimisation and improve the probability of increased gold recovery, as well as environmentally-friendly treatment technologies over a period of five years by students under the supervision of their academic staff members. The technological focus areas will comprise of four inter-related and interdependent categories, namely:

  • Alternative leaching technologies;
  • Fluidisation and recovery technology;
  • Environmental treatment technologies; and
  • Chemical measurements and modelling technologies.

Commenting on the agreement, manager of the program, Professor Herman Potgieter, said: “Through the four categories, Wits University will assist Ergo in developing new leaching processes and using alternative leachants and ligands for a wide range of sulphides, develop fluidisation and packed bed technology for a new gas phase technology for a wide range of sulphides. They will also obtain a detailed and thorough understanding of the environmental impact of the Ergo plant operations in terms of energy usage, effluents, and emissions during the liberation of the gold contained in the sulphides.

“The research will also assist Ergo in developing new measurement techniques to reliably quantify small amounts of gold in the leached solutions and predict the optimum reagents to use based on density functional theory calculations and modelling techniques applied to various parts of the process.”

Ergo’s Managing Director, Henry Gouws, said: “At DRDGOLD, we remain committed to engaging with educational institutions within the areas in which we operate to set up programs aimed at upskilling our youth, to empower them to make an active contribution to our economy. We look forward to working with the Gold Research Group within the School of Chemical and Metallurgical Engineering at Wits University as we seek to optimise and improve gold recovery as well as identify and evaluate environmentally friendly treatment technologies.”

Ergo has a vast footprint adjacent to Johannesburg on the central and eastern Witwatersrand of South Africa. Its assets cover an area around 62 km from east to west and 25 km from north to south. This large, single footprint was created as part of a rationalisation process and in order to simplify the structure of DRDGOLD, and focus on the reclamation and treatment of surface tailings deposits.

Zest WEG companies supply DRDGOLD with electrics for Far West Gold Recoveries project

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WEG Automation Africa and WEG Transformers Africa, part of the Zest WEG Group, have assisted with the commissioning of a containerised substation and control room solution at DRDGOLD’s new Far West Gold Recoveries project’s Phase 1 tailings site, in South Africa.

The gold tailings recovery project will see 500,000 t/mth of material pumped from the Driefontein 5 dam through a new 2 km pipeline to the Driefontein 2 plant.

Business Development Manager for Projects and Contracts at WEG Automation Africa, Tyrone Willemse, said the development of Phase 1 began in August 2018, with first commissioning beginning just four months later, in December 2018.

In an unusual step for such a project, the electrical portion was supplied ahead to the mechanical aspects to expedite the contract, according to Willemse.

“At the tailings facility, the customer required a medium voltage substation, a low voltage substation and a control room,” Willemse said. “This was accommodated within a double-container structure, which also included a room to house all the free-standing variable speed drives (VSDs) and uninterruptible power supplies (UPSs).”

The container was mounted on a concrete plinth with 2.5 m pillars elevating the structure to allow optimal visibility from the control room, according to the company. Heat losses were factored into the design to ensure the substation remained cool and the installation was fitted with a fire detection system.

Willemse said an important consideration was to reduce the footprint of the substation, with free-standing VSDs allowing this.

“Had the VDS configuration been a conventional design, these units would have been incorporated in panels and we would have needed an additional container,” he said. The VSDs are placed against the container wall and are completely isolated from any exposed conductors.

Motor Control Centres (MMC) were also provided for the modifications to the Driefontein 2 plant. The MCC for the thickener is fed by two 1,600 kVA transformers and the tailings MCC is fed by one 1,600 kVA transformer; both were manufactured at WEG Transformers Africa’s Wadeville facility.

Stuart Brown, Sales Team Leader at WEG Transformers Africa, said: “For this project, the transformers are designed to incorporate the VSD component of the load, and this demonstrates the engineering flexibility that WEG Transformers Africa can offer customers in meeting specific operating parameters. It is not a distribution transformer as such, but rather a VSD-type transformer.”

Cooling capacity had to be increased to accommodate the harmonics, and flux density is also reduced. The WEG transformers are built to SANS 780 specification, which stipulates losses even lower than the global IEC standard, according to the company. This will translate, over time, into energy savings for the customer, and is an important advantage, according to Brown.

Fabrication of all MCCs and the adaptations to the container were undertaken by WEG Automation Africa at its facilities in Robertsham, Johannesburg, and Heidelberg, further adding to the high local content on this project. This local manufacturing capability is a part of Zest WEG Group’s status as a B-BBEE Level 1 contributor.

Particular care was taken with on-site modifications at the plant itself. At the milling and classification MCC extension, WEG Automation Africa was required to connect to DRDGOLD’s existing MCCs. “The use of joggle chambers on either side of the existing board made for best practice and greater safety,” the company said. “On the return water MCC, a raised plinth was added for easier cable access. Top entry cables for the slurry receiving and tailings MCC was facilitated by innovative board design.”

The MCCs incorporate an extensive range of WEG LV products including WEG air circuit breakers to facilitate a 50 kA fault level, WEG moulded case circuit breakers, WEG contactors, WEG fast-acting high rapid fuses, and WEG motor protection relays.

WEG W22 LV electric motors were selected to drive the tailings facility pumps, ensuring lower energy consumption through the design of these units, which have an optimal cooling fin design, the company said. Ingress protection is to IP66 ensuring effective sealing against liquid and dust.

WEG Automation Africa, formerly known as Shaw Controls, recently changed its name to align with parent company, Brazil-based WEG’s global strategy. Its local manufacturing operation has been the recipient of an extensive investment programme by WEG that has seen its facilities upgraded as part of the ongoing commitment to the South African economy and customers in the region.

DRDGOLD gears up for Far West Gold Recoveries commissioning

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DRDGOLD says commissioning of the Far West Gold Recoveries project, previously the West Rand Tailings Retreatment project, is set to start on December 6.

Commissioning of the South Africa project will begin with the pumping of reclaimed tailings into the carbon-in-leach circuit. This comes just four months into the construction of Phase 1.

Far West Gold Recoveries was acquired from Sibanye Gold, trading as Sibanye-Stillwater, at the end of July. Stage 1 of the project involves upgrading of the Driefontein 2 plant to treat material from the Driefontein 5 dam.

DRDGOLD CEO Niël Pretorius said: “The project is on track to achieve full production of 500,000 t/mth from Phase 1 in the first quarter of 2019.”

As part of early-stage commissioning, a face has been established at the Driefontein 5 tailings dam reclamation site, from which pumping of reclaimed tailings through a new 2 km pipeline to the Driefontein 2 plant is set to begin. A parallel pipeline to return water from the plant to the reclamation site has been completed, DRD said.

Work to upgrade the plant’s retreatment capacity is well advanced, with carbon loading – also part of the overall commissioning process – set to begin immediately.

An 8 km pipeline to transport retreated tailings from the plant for cyclone deposition on the Driefontein 4 tailings dam and a parallel return water pipeline from the deposition site to the plant have also been completed.

Phase 2 of the project, which involves consolidation of what remains of Phase 1 material and the remaining tonnes of material acquired, envisages a monthly production rate of 1.2 Mt and is planned to be enacted within 24 months after the start of Phase 1 production.

Key features of Phase 2, feasibility of which will be tested over the next two years, are the construction of a large, centralised plant and an ultra-high volume deposition facility.

The acquisition of the project saw DRDGold increase its gold reserves by 92% to 5.75 Moz.

DRDGOLD completes WRTRP acquisition, welcomes Sibanye-Stillwater as shareholder

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DRDGOLD has completed the acquisition of Sibanye-Stillwater’s West Rand Tailings Retreatment Project (WRTRP) assets in South Africa, over nine months since the deal was initially announced.

Niël Pretorius, DRDGOLD CEO, said the acquisition was key to the company’s growth strategy, increasing its gold reserves by 90% to 5.75 million ounces.

“The way is now clear for us to expedite phase one of our phased plan for the development of WRTRP, to be known going forward as Far West Gold Recoveries,” he said.

“Phase one involves the upgrading of the Driefontein 2 plant to process tailings from the Driefontein 5 dump at a rate of between 400,000 and 600 000 tonnes per month and depositing the residue on the Driefontein 4 tailings dam.”

DRDGOLD has secured a R300 million ($22.6 million) revolving credit facility from a South African financial institution for phase one, and confirmed orders for most of the long-lead items, according to Pretorius. This is all geared towards production in the March quarter of 2019.

Sibanye-Stillwater now holds 38.05% of DRDGOLD and is entitled to exercise – within 24 months – an option for cash to increase its shareholding by up to 50.1%.