Modern Quarrying Q1 2019

Regarded as the main process in aggregate production, crushing is the first controlled size reduction stage and is the basis for optimal further size reduction. It is, therefore, important that when choosing a new rock crusher the first thing you need to know is which one best matches your material – and it is imperative to find the right one the first time, writes Munesu Shoko . ATTAINING COST-EFFECTIVE CRUSHING

CRUSHING

B y tonnage, crushing is by far the largest process operation in aggregate processing. To execute this process cost- effectively, it’s always important to deploy the correct crusher for the ideal application. This not only saves you time, but it will also save you money in the long run. Just how important is crushing in the whole aggregate production equation? To reiterate the significance of the process, Heath Dickson, national mining sales manager at ELB Equipment, says “simply put, without crushing, in specification aggregate would not exist”. JD Singleton, process director at Weir Minerals Africa, says size reduction in aggregate production is required to achieve the different product gradations used in different

serve as aggregate, crushing forms a vital and cost-effective part of the aggregate production process. “It allows us to reduce the particles to a required size under applied stress through one or more crushing stages in conjunction with screening to achieve the required specification of the final product,” he says. Van Rensburg adds that key aspects of designing and implementing a crushing circuit include, firstly, understanding asmuch as possible about the source material – such as the size of the rock entering the process, the hardness of the material and its abrasiveness. “Most importantly, the designmust focus on exactly what output the customer requires – both in terms of particle size and volume of output in a specific timeframe. On the strength of these considerations, it can be decided whether the processmust be single-stage or multi-stage, and the

end processes. “The primary objective of a crushing stage is size reduction, so having the correct crusher in the correct duty is essential for quality aggregate production,” he says. Sandro Scherf, CEO of Pilot Crushtec International, shares the same view, saying that the crushing stages are critical to achieving the right quantity and quality of aggregate products. “Similar to driving a vehicle, to reach top speed you need to go through various gears; in aggregate production, you need to go through various crushing stages. The number of crushing stages will vary depending on production requirements such as the quantity you need to produce and the specifications of the final product,” says Scherf. Dewald Janse van Rensburg, MD of B&E International, says by applying compressive strength to the strong and brittle natural rock types that

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MODERN QUARRYING QUARTER 1 - 2019