JOHANNESBURG (miningweekly.com) – Surface gold miner DRDGold is planning to use treated wastewater rather than potable water for tailings upkeep and mining at its Crown Tailings complex.

Digby Wells Environmental, which has been appointed by DRDGold’s Ergo Mining as its independent environmental consultant, stated in a newspaper advertisement on Wednesday that the Gauteng Department of Water and Sanitation had approved the proposed use of treated water for mining related requirements.

DRDGold is listed on both the Johannesburg and New York stock exchanges.

“Ergo will be using treated sewage water to irrigate tailings dump vegetation for the first time. Treated sewage water will also be used in the mining process,” Ergo Mining operations director Jaco Schoeman confirmed in an emailed response to Mining Weekly Online.

He said that the use of ‘grey’ water would reduce the company’s dependence on potable water, which was significant in a water-stressed country where industry often competed with communities for this resource.

“It also results in less contaminated water being introduced into river systems,” Schoeman added on the project, which is not expected to cost more than R25-million.

“It’s in line with our commitment to sustainable development and the strategic allocation of resources and capital.

“In this case, the overlap of financial and environmental capitals are translated into cost savings and the reduction of the company’s environmental footprint,” Schoeman added.

Digby Wells Environmental said that Ergo proposed to build a 6 km pipeline from the Johannesburg City Council’s Goudkoppies Waste Water Treatment Works to the company’s Crown Tailings complex, near Diepkloof, Soweto.

The treated Goudkoppies water, the consultant reported, would be additionally filtered to ensure further removal of suspended solids and pumping would be at a rate of 231 ℓ of wastewater a second, through 50-cm-diameter piping that would be lined with high-density polyethylene.

The Crown Tailings complex is irrigated daily to sustain vegetation growth on its slopes to reduce erosion, dust and slope instability.

Currently, potable water from Rand Water is used for this purpose.

The buried pipeline that will transport the treated effluent will be located predominantly within a power servitude, for which State electricity utility Eskom has reportedly given approval in principle.

Schoeman said that another wastewater plant being implemented by the company for the same purposes, at the Rondebult Waste Water Treatment Works, was scheduled to be in operation by July, ahead of the Goudkoppies project, which still has 18 months to go.