The first Warman MCR mill circuit pump supplied in Africa is currently pumping mill discharge slurry at mining company First Quantum Minerals’ Frontier copper mine, in the Democratic Republic of Congo (DRC), on a trial basis.
The negotiations to supply the pump started in November 2008, with the agreement to trial being concluded in November 2009. Commissioning of the pump took place in March 2010. The Warman MCR is halfway through its trial and has improved the mine’s productivity and increased its output tonnage by about 200 t/h, says Weir Minerals Africa slurry pumps product manager Rui Gomes.
“The 17-t pump, which was shipped in kit form, has been available globally for six years and is, therefore, a tried and tested product that has been constantly improved since entering the market. To date, the mine has been running continuously for 20 weeks and we haven’t replaced any wearing parts on the pump, proving that the Warman MCR has better wear life than other similar pumps available,” he says.
A pump that can function continuously for six to eight weeks is generally acceptable in the mill discharge application arena, but the Warman MC has surpassed these expectations and substantially reduced downtime.
At the Frontier mine, the pump is located at the start of the milling process. It is the first pump that comes into contact with the ore and if it stops functioning, production will stop.
The ultraheavy-duty pump’s wear life is improved by the impeller size. Being larger in diameter than a conventional design, the pump is able to run at slower speeds, and has adjustable front and backside liners to reduce recirculation. The adjustments to the liners take place weekly and can be performed on site while the pump is running.
“The adjustable liners are a great improvement in terms of maintenance, as it only takes 10 to 15 minutes to adjust them,” explains Gomes.
Weir Minerals has also included its R55 propriety rubber, which has proved to have good wear resistance in the company’s rubber-lined pumps and increases the wear life of moving parts. The R55 was developed specifically for mill circuit applications, particularly pump liners that fail or leak when torn by sharp particles of ore and metal fragments typically found in slurry.
“Before the R55 development, we used metal volutes. However, when the product contained highly abrasive silica, the metal would wear away quickly, causing premature failure of the pump,” Gomes adds.
“We are supplying a product that takes much longer to wear, reducing the need for replacement spares. This demonstrates our commitment to the client’s best interests and lowest cost of ownership,” says Weir Minerals Africa marketing manager Rene Calitz.
Like some other mines, the Frontier mine does not have pumps on standby in case one fails. Therefore, the availability and increased operating time of the mill circuit pump has become paramount. Coupled with the MCR pump’s low maintenance and the avail- ability of product, the profitability of the operation has improved.
“The opportunity was taken to fully inspect the pump when the mill was stopped in April. Since it was commissioned, the pump has been inspected twice. A complete wet-end overhaul of the pump system [takes] 4,5 to 8 hours, depending on the labour and equipment available,” says Gomes.
To assist the Frontier mine with maintenance training, a specialist in pumps was flown in from South America. He also commissioned the pump and is supported by a local Weir Minerals technician based in Zambia.
“The company’s offering all depends on what the customer wants in terms of maintenance. We readily share knowledge and spend a lot of time and money on providing training for our clients. This also serves to uplift the industry, in general. However, if clients do not have the resources to maintain the product themselves, we are able to supply them with a comprehensive maintenance and service contract,” says Calitz.
Meanwhile, two other copper mines in Zambia are also interested in the product trial, with West Africa’s interest also starting to peak, particularly in Ghana and Mali, says Gomes.
“In South Africa, the ore grade tends to be higher than that of the DRC and Zambia. This enables mining operations in the country to use smaller pumps offered in the Warman MC range. There is also interest from the platinum sector, in Rustenburg, in the North West province,” he concludes.