MechChem Africa December 2018

⎪ Pump systems, pipes, valves and seals ⎪

“It is standard practice in most of our pontoon designs to mount the pump sets at 30° to submerge the suction eye of the im- peller, thereby ensuring consistent priming,” Matthews says. Oneof themost important factors affect- ing the solution was Madagascar’s weather conditions, which include regular tropical storms andhighwind speeds. Thesehave the effect of creatingwave actionandwind load- ing on the pond, which the pontoon solution has to accommodate. To address the wave action and mini- mise possible structural damage, the fixed walkway was designed to incorporate a pivot systemon the bank landing structure. This allows the entire assembly, including the docking station, to rotate 90° and still be tied down to the shore during these storms. “Madagascar is also known for its var- ied wildlife, including crocodiles,” says Matthews. These creatures tend to climb onto the deck to bask in the sun, making it almost impossible for staff to conduct rou- The high resilience rubber wear liner enables the handling of coarse particles and ball scats with ease, while its lightweight design relative to other pumps in its category facilitates safer handling. These liners also come in at a lower cost than traditional heavy metal liners. Importantly, different material combina- tions are available to ensure that customers get a fit-for-application pump capable of pro- viding reliable performance cost effectively, tailored to their site conditions. The Warman MCR pump has a large di- ameter, low speed, high efficiency impeller. Koorts explains that this canbemanufactured from a range of abrasion resistant alloys, al- lowing the most appropriate material to be selectedforthecustomerapplication.Thiswill increase wear life and reduce operating costs whencomparedtootherpumpsinitscategory. Reduced recirculation is achieved by the deep expelling vanes on the front of the high-chrome impellers. Expelling vane tip tur- bulence is minimised by the patented shroud feature that traps tip vortices and prevents localised scouring on the throatbush face. This, again, extends wear life and reduces maintenance. The split outer casing on the Warman MCR pump provides structural integrity and high operating pressure capability, ease of maintenance and safety. This feature also allows internal liners to be fully worn before replacement. Warman throatbushes feature pre-swirl vanes, which offer optimum reliability and

The split outer casing on the Warman MCR pump provides structural integrity and high operating pressure capability, ease of maintenance and safety.

tinemaintenance.Restrictingthisaccesswas achieved by closing all the gaps between the handrails and the separate structures. “Our design took all the site conditions into account, making for better and more predictable operational reliability,” he adds. “Both the pontoons and the pumps can now be easilymoved for servicing or for securing during bad weather.” wear life. There is a patent pending on this innovative throatbush design, which was developed to improve impeller eye wear life and reduce the wear caused by recirculation at the impeller/throatbush interface. This has been accomplished by a series of guide vanes in the pump inlet, which induce a rotational velocity in the slurry. An adjustable stuffing box allows for the centering of the stuffing box and lantern restrictor to the shaft sleeve. This increases packing life and decreases gland seal water

Weir Minerals Africa’s experience with mounting pump sets onto pontoons and its extensiveprocess-relatedknowledgeplayed a significant role in developing the product offering for the customer. “Itwas also important for thedesignengi- neers to be present during the commission- ing process to ensure support,” Matthews concludes. q “Our Warman Mill Circuit pumps are engineered to offer the most cost effective solution across a range of applications, and with installations on many leading mine sites across the globe it is proven to be themill cir- cuit pump of choice for the hard rock mining industry,” Koorts concludes. q consumption. Another new design feature is the single-point gland adjustment, which facilitates safe packing adjustment outside of the stuffing box guard while the pump is operating.

One of the two Multiflo ® pontoons installed at a mine in Madagascar, which consist of Warman AH pumps coupled to variable frequency drives (VFDs).

December 2018 • MechChem Africa ¦ 13