As cyanide leaching remains the most economically viable and efficient method of recovering gold from gold-bearing ores, pumps technology company Verder Pumps’ Verdermag mag drive pumps, which are economic and cost effective, have been specified in the cyanide code of a global gold mining company, states Verder Pumps South Africa sales engineer Rob Shaw.

The Verdermag range is a series of magnetically coupled centrifugal pumps.

“Such a safe and economical pumps solution for cyanide leaching is revolutionary for the gold mining industry,” he notes, adding that, with cyanide leaching, microscopic gold particles can be extracted from ore rocks, increasing the yield and contributing to making operations more profitable.

However, it is a dangerous method, which, if not managed correctly, has the potential of being very damaging to the environment, he adds.

“Cyanide has many adverse environmental consequences, as it can possibly pollute the land surrounding the plant, contaminating aquifers and decimating life in water courses,” says Shaw.

The traditional dosing solution comprises progressing cavity pumps that have integral seals, requiring regular replacement and presenting a clear leakage risk.

Most gold miners using the cyanide leaching method have specified peristaltic pumps for the dosing process. Peristaltic pumps are sealless and, consequently, have a much lower contamination risk, but challenges related to this solution include limited flow rates and contamination risk, owing to hose bursts, Shaw points out.

“However, the magnetic drive pumps are sealless and are guaranteed not to leak,” says Shaw, adding that the Verdermag drive pump, which pumps at 30 000 ℓ a minute, is more than three times less expensive than a peristaltic pump for the same duty.

The Verdermag magnetic drive pumps have no glands, no seals and no valves, he notes, pointing out that, unlike sealed centrifugal pumps, the sealless construction of the Verdermag magnetic drive pump allows total containment of aggressive products.

The Verdermag series of pumps comprises the nonmetallic heavy- duty TB, U, V&W series and the normal-duty V-MD, GPMD and GLMD versions.

“Even under heavy-duty circumstances, the pumps are extremely reliable and the series of Verdermag pumps can be used in a wide range of applications, particularly in the pumping of toxic waste, acid, cyanide, reagents, and any media that are usually problematic for mechanical seals, such as nitric acid, phosphoric acid, copper sulphate and sodium chloride,” Shaw adds.

In addition, the leakproof coupling between the motor and the pump ensures a clean and safe operating environment.

As the gold mining industry is still under a lot of pressure in terms of the global economic environment, Shaw points out that gold miners have to use technologies that will reduce cost and boost production, while complying with health, safety and environmental regulations, a solution which the Verdermag drive pumps provide.