A South African gold mine has successfully used slurry pumps to reprocess extremely dense gold-bearing slurry from a return water dam which was identified as a valuable source gold.

The mining operation deployed Grindex Bravo 500 slurry pumps from Integrated Pump Technology to reprocess slurry from its surface return water dam which had been used for process water storage over the past 12 years. The operation aimed to transfer the slurry back to the gold processing plant.

Integrated Pump Technology key accounts manager JD Nel explains that the return water dam was a crucial gold resource needed for production while underground maintenance, which temporarily halted recovery from an underground section, was underway. The return water dam resource was used to sustain gold production for the plant’s needs, but the extremely dense slurry, with a specific gravity (SG) of 1.38, presented a challenge.

Nel says that while it was not necessary to modify the existing process plant, as the material fed from the thickeners had a similar SG, it was important that the pumps selected would perform reliably within the application parameters.

“Following a full assessment of the site conditions and application, we had no reservations in specifying the Grindex Bravo 500 as we knew this centrifugal pump could withstand the density of the material, but still transfer it at the required flow rate,” Nel explains. “The Grindex Bravo 500 is engineered for heavy-duty applications and its components, especially the impeller and liner, are designed to withstand the abrasive nature of dense slurries.”

One of the critical factors in the success of this project was the flow rate and reliability of the slurry pumps. In this application, material is being transferred at a flow rate of 480 m3/h at a head of 18 m. In total, three Grindex Bravo 500 pumps were employed to handle the demanding requirements of this gold mining reprocessing effort.

Nel says the Grindex Bravo 500 is designed to handle high head pressures which is crucial for transporting dense slurries over long distances or vertical lifts. The pump’s ability to maintain consistent pressure helps in effectively moving heavy slurries through the system.

“Further,” he says, “the pump features a robust impeller designed to handle the high density and viscous nature of the gold slurry. The impeller’s design ensures efficient movement of the slurry, significantly reducing the risk of blockages and ensuring smooth operation.”

The overall design of the pump includes heavy-duty bearings and a robust shaft to handle the stresses associated with pumping dense slurries. In addition, the pump’s design helps in minimising the risk of cavitation, a phenomenon that can be problematic when pumping slurries with high densities.

A Grindex Bravo 500 was also deployed to pump clean water from the return water dam to the plant where this was being used to wash any material back into the system.