Modern Quarrying Q2 2019

and 300 tonnes per hour. The crusher dust is currently the largest volume driver. To give an idea, at Shaft 4 plant, CNC Crushers is producing 1,3 tonnes of crusher dust per minute, highlighting the highly productive nature of the plant. In addition to the purchase of new Trio ® equipment, a service agreement was signed between Weir Minerals and CNC Crushers. Regular inspections are conducted by a Trio product support specialist and all machines are well maintained. Services are performed at 300-400 hour intervals. “The service agreement ensures best practice is adhered to in operating and maintaining the equipment. This helps the plant to achieve maximum availability and long operational life of its equipment,” says Lapidoth. Key results from the interventions at Shaft 4 plant include a 60% improvement in plant production owing to maximum availability of equipment, as well as a 13% reduction in downtime related to liner changes. “Another key benefit has been the improved variety of product specifications from multiple product screens. Previously this would be achieved by blending from different stockpiles using front- end loaders,” says Lapidoth. “Our start-up procedures have become quick and simple, while adjustment of the crusher CSS takes only five minutes compared with 90 minutes with the old technology crushers we used to run. The plant is just a pleasure to run and that, coupled with the right support behind us, is a winning formula for us,” concludes Willie Crous. l

crushers, they had to change socket liners after every three months. This has since been improved to 2 700-hour (12- month) socket liner replacement intervals with the Trio ® TC51S and TC36SH. “With every socket liner replacement on the old generation crushers we had before, we also had to do an oil change, putting in about 500 l on each occasion,” says Crous. “Loss of operational time due to adjustments and starting up of old technology crushers was also a major challenge for us, as it affected production output.” While bowl and mantle liner replacement cycles have pretty much remained the same at between 650 and 700- hour intervals, there is a huge difference in the throughput. With the Trio ® TC51S and TC36SH, a total of 250-350 m³ material goes through the crusher liners per hour, while 120-150 m³ per hour was achieved with the previous cone crushers. As part of the upgrade, three Trio ® inclined screens were installed, namely the Trio ® TIO5163, TIO6203 and TIH4102. The screens are capable of producing a variety of product specifications directly without the need to blend material. When we visited the site, CNC Crushers was producing five different specifications of road stone. These included 6,7 mm; 9,5 mm; 13 mm; and 19 mm stone, as well as crusher dust. By just changing the screen mesh sizes, CNC Crushers has the capacity to produce extra product specifications. The plant has the flexibility to produce between 250

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QUARTER 2 - 2019 MODERN QUARRYING