As IM‘s special annual South African feature is prepared for publication in the January issue, comes news that the largest self-driven trommel ever built by Multotec has been successfully commissioned at QMM’s Mandena mine in Madagascar where it is installed in the mine’s heavy minerals process plant. The trommel has the same diameter as the one Multotec manufactured for Hillendale more than ten years ago, but it is far longer. This massive trommel has a 3.5 m diameter, is 15 m in length and weighs just under 50 t. It will process 3,200 t/h of dry solids or 5,943 m3/h of heavy minerals slurry. This is almost double that of the Hillendale trommel.
Spaltoflex hand cast polyurethane panels, each 1,086 mm x 1,000 mm, have been fitted to the trommel. These large panels, with slotted apertures were selected as they provide good life and are easier to replace during maintenance. The trommel also has steel rubber-lined bolt-on scrolls to convey the feed through the trommel in a uniform manner. The trommel is equipped with a peripheral discharge arrangement and is driven by a Hägglunds variable speed drive system. “This hydraulic drive system facilitates variable speed allowing optimisation of the screening process,” Anthony Yell, Product Manager Screening explains.
Significantly, a number of other Multotec products have also been commissioned on the wet plant. Two static screens fitted with modular polyurethane panels (305 mm by 305 mm) were supplied, and the feed boxes on these screens are ceramic lined with engineered high alumina ceramic tiles to optimise wear life. Vezin wet sampling systems have been installed on the rougher, cleaner and scavenger spiral plants, allowing a representative increment sample to be taken. The dry plant has six wet vezin samplers, two telescopic samplers and six belt end samplers, all of which allow for accurate samplers in their individual applications.
Eight stacker dewatering cyclones, each with a 420 mm diameter, and six cyclones being used for dense medium separation. The latter are rubber-lined cyclones. In addition, two larger stacker cyclones, each with a 1,200 mm diameter and ceramic lined, are installed in the tailings circuit. All the cyclones were supplied by Multotec.
Multotec modular polyurethane screen panels are installed on all four vibrating screens at the plant. The proven Saddle Top system has been used to secure these panels and will minimise maintenance downtime on the screens.
The plant is situated in a remote part of Madagascar on the coast where there is no modern infrastructure, and as part of the project a new harbour and power station was built to service the plant and the local community. All the products were shipped to this new harbour. “It is not unusual for Multotec products to be spread across a plant such as this,” Yell says. “The group has a comprehensive range of minerals processing plant and equipment and is able to provide an appropriate cost effective solution.”