Where water comes at a premium, creative cost-effective solutions follow, thanks to Watercare’s industrial water treatment plants. One of Watercare Mining’s unique core competencies is the way we design, engineer, build and operate unique, customised water plants that treat complex water to drinking water quality.

In this case, we set out to fundamentally understand the nature of the plant’s feed water, the site-specific requirements, and its environment and then designed a customised process that not only meets but exceeds the mine’s needs.

The mining operation is water positive. This means that underground water needs to be pumped to the surface continuously, to ensure sustainable and safe mining.

The escalating cost of municipal water initiated a strategy to reduce the demand, by converting excess mine service water to a quality suitable for distribution as potable drinking water and for use in the metallurgical plant.

Excess water was to be released into the natural waterways, in a way that is compliant with the mine’s Water Use License.

Various technologies, including filtration, ion exchange and membrane technologies were combined to generate this safe water.

A bank of ultrafiltration units in the mine water treatment plant

Watercare Mining designed, built and commissioned the mine’s water treatment plant to treat 5 500 m³/day of mine return water.

The plant has 2 circuits:

• the Potable Circuit, which treats 3 200 m³/day via reverse osmosis (RO) at a recovery of 85%, and
• the Discharge Circuit, which treats 1 500 m³/day treated via ion exchange at a recovery of 74%.

The Potable Circuit produces water that meets the SANS 241-2015 potable water standards. It comprises sand filters (see top image), an ultrafiltration membrane bank (see image above) and a reverse osmosis plant (see image below). The water which is produced is remineralised and disinfected to enhance the water quality and safety.

The Discharge Circuit produces water that meets the quality standard set out in the Department of Water Affairs’ Water Use License, issued to the mine for excess water discharged to the river.

This circuit includes granular activated carbon filters and an ion exchange plant. Dissolved organic and heavy metal contaminants are removed through this process.

3 200 m³ of water is treated via reverse osmosis per day

Watercare Mining used a “Build-Sell-Operate” model as their business approach for the water treatment plant. The mine purchased the plant, and pay monthly for a guaranteed supply of good quality water.  The water treatment plant is operated and maintained by Watercare’s skilled engineers and technicians.

Watercare Mining’s technical services laboratory supports the routine monitoring of the potable water according to the SANS 241-2015 requirements. Watercare Mining supplies all reagents and chemicals required for the operation of the plant. The plant is also remotely monitored by Watercare Mining’s control room, through an online Scada system called WaterBizz.

The fact that Watercare Mining is in full control of the operation of the water plant (a non-core operational function for the mine) decreases the operational load on the mine.

Watercare Mining supplies the water 45% less per unit volume than that supplied by the local Water Board, and the calculated ROI on the water treatment plant is 36 months.

The success of this project has been to the benefit of the mine, its local community, the environment and Watercare Mining.