Browsing by Author "Olivier, Warren John Lloyd"
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- ItemInvestigating the Hi-G Dryer System on coarse daberas slurry material(2015-03) Olivier, Warren John Lloyd; Els, Ellis Raymond; Stellenbosch University. Faculty of Engineering. Dept. of Process Engineering.ENGLISH ABSTRACT: Namdeb Diamond Corporation is constantly investigating and investing in technologies to continuously improve performance and productivity. Diamond mining operations have been taking place for more than a hundred years – ever since the first diamond was discovered in 1908. Diamonds are a scarce and finite resource. As current resources are being depleted, the Namdeb exploration team are exploring areas not previously considered feasible. One such resource is the Sendelingsdrift resource, situated about 20 km from Daberas, one of the current Namdeb operations along the Orange River. When an environmental assessment was conducted, it was discovered that the Sendelingsdrift area was environmentally sensitive in terms of constructing a slimes dam, creating difficulties for slurry processing. Thus the Derrick Hi-G Dryer Fines Recovery System was considered as a probable solution; unfortunately it was found that the slurry discharge would be too coarse for this technology. The Hi-G Dryer technology has never been tested with a coarse slurry feed. The Daberas processing plant produces slurry of -3 mm particles, which is very coarse compared to the 75 μm particles with which the Hi-G Dryer system normally operates. Testing was conducted at Daberas by directing the Daberas wet-sizing underflow as feed to the Hi-G Dryer system. The majority of the testing was done under production conditions, which proved to be very difficult. The results of the initial supplier-designed Hi-G Dryer processing system produced an oversize moisture content of 17%, which was better than that which the supplier had claimed but not as good as that which the existing Daberas degrit system produced. After studying the system parameters and optimising certain parameters, a proposed Hi-G Dryer system was recommended for coarser slurries. The new process parameters generated improved results, with an oversize moisture content of 13% – better than the Daberas dewatering system benchmark. The Hi-G screen oversize material also proved to be conveyable and was quantified with oversize yield stress test results. Overall system efficiency was improved after the recommended modifications to the design had been made and a simulation had been conducted to understand the impact of certain parameters on the overall system.