“The initial milestone of matching or improving on the 2 100 t/h, achieved by the original pumps, was quickly achieved,” Gomes says, adding that the second and more critical goal was to increase the wear life of the pumps, for which the target of 1 000 hours of operation without failure was also achieved. In addition, the impeller lasted about 1 900 hours before requiring replacement, while the R55 rubber liners continued without needing replacement, he notes.

“A number of factors drove the success of this trial. Firstly, the pump design was ideally suited to the application, compared to the pumps previously installed – notably the contribution of the MCR’s rubber lining to the substantial increase in its wear life and the consequent improved mill availability,” he says, noting that the company was astounded by the performance of the rubber liners, compared with the metal volute originally in place.

“At the four-month inspection, there was still a substantial amount of residual value on the liners and we estimate getting to about 6 000 hours – six times as long as the life of the metal volute.”

In another successful installation in the West African gold industry, a Warman 350MCR was installed to be compared with a Warman 16/14 AH metal pump. The mill was operating at flows of about 2 000 m3/h to a head of 38 m and the Weir Minerals Africa team had to install the MCR pump to fit in with existing pipework and foundations. The complete wet-end was retrofitted after about 1 400 hours, which more than doubled the life of the metal volute of the 16/14 pump, and effectively improved plant availability, Gomes notes.

“This particular site was experiencing the fairly common problem of mill balls coming through the system and cracking the metal volutes,” he says, but notes that the R55 rubber liner offered an indirect but immediate solution to this operational issue.

“The customer was also impressed by the quick and easy adjustment capability, the reduced cost of replacement spares and the improved safety levels. This MCR was installed in 2012 and we’re receiving similar feedback after 18 months of operation,” he says.

Meanwhile, a third gold mine in West Africa agreed to trial a MCR pump against its existing 14/12 AH pump. A full technical team from Weir Minerals Africa designed, supplied and fitted a retrofit base. This plant was poised to increase its tonnage to 3 000 m3/h to a head of 39 m to boost output, he points out.

“The throatbush ran for about 2 000 hours – far more than what was being achieved with the 14/12 metal throatbush,” Gomes says, noting that both the impeller and the liners were intact and are still running at the moment, after about 3 000 hours without replacement.

Further, he notes that the burgeoning interest in the Warman MCR pumps is primarily driven by the improved total cost-of-ownership being achieved, and adds that the company also experienced positive spin-offs from greenfield projects in Central Africa, Zambia and the Democratic Republic of Congo (DRC).

“Most recently, a project house, which manages a recently commissioned greenfield copper plant expansion in the DRC, opted for MCR pumps, based on the increasing number of impressive case studies being rec- orded for this particular pump,” Gomes says.

Meanwhile, he notes that, in terms of brownfield applications, tonnages and requirements change over the years, but the pumps rarely change.

“This could be detrimental if the pump becomes too big for the duty, impacting on efficiencies and pump life, or too small, affecting wear life. We’ve now proven that we’re able to retrofit MCR pumps into existing piping and foundations to achieve significant improvements with little or no downtime,” he comments, adding that the company had started to focus on a variety of commodity plants where there is pressure to drive costs down and improve processes.

He concludes that, from a manu- facturing perspective, the company has improved availability of the MCR pumps by manufacturing many of the MCR components locally over the last three years.

“This has enhanced our offering through improved lead times and route to market. We started out with three pump sizes in 2008 and we now offer six sizes, with various com-binations for each size,” he adds.