OPERATIONS • dealer helped SMB estimate production and service expenses associated with using the Vermeer Terrain Leveler SEM . Impressed with the results of the testing , associated production and cost estimates and the responsiveness they received from their Vermeer dealer the SMB group decided to give precision surface mining a try .
Side-by side comparison SMB invested in two Vermeer Terrain Leveler SEM ’ s for the mine and decided to run the machines in conjunction with its drilling and blasting methods . The mine was divided into two areas , so the team could get a side-by-side comparison .
“ Drilling usually occurs a week ahead of blasting and involves several drilling machines to produce a five-by-five metre ( 16x16 foot ) grid of boreholes ,” says Shiliang . “ About a week after the drilling process is complete , we ’ ll then come through and blast . Close to 50 000 to 100 000 metric tons ( 55.000 – 110.000 US tons ) of bauxite is extracted each time . The material produced ranges in size , so additional screening and crushing is necessary , which can certainly have a major impact on our operational costs ,” Shiliang adds .
SMB found precision surface mining methods to be more straightforward , with less preparation time , and fewer steps involved . Using top-down cutting , the Terrain Leveler SEM is able to work the ground layer by layer , while producing consistently sized product that does not typically require additional screening or crushing . Smaller-size product justifies the use of regular trucks over high-weight / high-cost mining trucks and can be more cost efficient .
In addition , the Vermeer Terrain Leveler SEM offers manoeuvrability , which allows the operator to surface mine more selectively in small areas and perform on slopes up to 20 degrees . And , according to Shiliang , the SMB consortium has been impressed with this new way of surface mining . “ Overall , using the Terrain Leveler SEM machines is more cost efficient than drilling and blasting for our operation ,” he explained . “ We are saving on labour expenses and have been able to reduce the number of times that material has to be handled .”
90 % to 92 %. Those totals have continued to rise each year after , and the group expects increased production of ore per unit in 2018 .
Getting support Another area of concern the SMB consortium had as it explored surface excavation machinery was what they could expect for parts and service support . “ Since our operation is in a remote area , dealer support is always a major concern with every machine in our fleet ,” says Shiliang . “ Before selecting the Vermeer Terrain Leveler SEM , we vetted a few manufacturers and their dealers so we could determine how well they would support our team in the field . The Vermeer West Africa dealer , along with the Vermeer team in Europe and the US , were accommodating during that process , and they have done a tremendous job of supporting us since then .”
According to Shiliang , Vermeer provided a service rather than merely trying to sell him a machine . “ There was a lot we didn ’ t know about this new way of surface mining , and we had a lot of questions . The Vermeer team helped determine the best way to use the surface excavation machines at our facility . Any time we ’ ve had a machinerelated issue , Vermeer West Africa has been quick to deliver onsite support and any needed parts . That level of support helps to maximise our run time ," says Shiliang .
Plans for the future After comparing precision surface mining to drilling and blasting , SMB plans to incorporate more surface excavation machines into its operations . However , the group still plans to use drilling and blasting methods in areas of the mine where it is challenging to load material due to the extreme steep inclines . “ We have been able to prove that precision surface mining methods can be cost-efficient for bauxite mining operations ,” says Shiliang . “ These machines are really the future of where our company and the industry are going .” •
Shiliang also notes that loading trucks in the cut has been more efficient since the Terrain Leveler SEM surface mined surface area is much smoother . “ We spend less time preparing and maintaining haul roads , manoeuvring trucks in and out of the cut , and there is significantly less damage to tires ,” he says . |
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Making the cut In the first year of operating , two Vermeer Terrain Leveler SEM machines at the Boké mine , SMB estimated each unit produced around 2.75 Million tonnes per annum ( Mtpa ) ( 3 million US tons ) of ore with a mechanical availability in the range of |
Guinea is richly endowed with bauxite . |
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African Mining Publication |
African Mining |
African
Mining • February 2021 • 21
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