Engineering & Mining Journal

OCT 2018

Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr

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HOISTING SYSTEMS 64 E&MJ • OCTOBER 2018 BMR, like the one selected by Anglo- Gold for Moab Khotsong. For the Deeps, each was considered. The geared configuration was ruled out due to the large drum and expensive components. The in-line configuration was eliminated due to drum width. The electrically coupled BMR had a higher capital cost, heavier components, and would use more energy. "Due to the head gear layout, the head frame lay- out and the hoist house arrangement, a Hooke's joint-type BMR was required to solve the fleeting angle challenges," Koekemoer said. The typical Hooke's joint solution is comprised of three parts, two yokes and a center block, or spider, FLSmidth re- ported. "The Hooke's joint used as a sin- gle joint will transmit nonuniform mo- tion between input and output shaft," the company reported. "The variation in angular velocity at the output shaft is a function of the angle between both shafts; a method to mitigate this attri- bute is to make use of a double joint." The design allowed the drums to be positioned asymmetrically, which saved space. Installation of the hoists required overcoming significant logistical chal- lenges, Koekemoer said. "All service assemblies are trial-assembled in the manufacturing shop in the Vienna-Jo- hannesburg area of South Africa, but then taken apart and shipped piece by piece, and then assembled on site as the machine progresses," he said. Road conditions were less than ide- al. "The drum shafts for these machines weighed in excess of 61 mt," Koekemo- er said. "Transporting those by road was quite a challenge" and not entirely without incident." During the staged assembly that followed, the FLSmidth team was lim- ited to use of a single overhead crane. "Since the pieces of the drum, the drum shaft, the motor rotor, the motor stator are all considered the heavy-lift components, the timing had to be well- planned," Koekemoer said. Which it was, with the result that the hoists were installed on time, within the budget, and with the miner "all happy," amounting to "quite an achievement," Koekemoer said. Annual production at Mindola and Mufulira will eventually target 3 million mt per year, a goal the hoists enable the miner to attain, Kennedy said. "These are impressive machines in terms of speed and connected power and that sort of thing," he said. They are also harbingers of the fu- ture of deep underground mining, Ken- nedy said. "There is a marked increase in feasibility studies going on for BMR applications," he said. "Five or 10 years ago, you'd seldom see a request for a BMR. These days they occur sever- al times per year." Ultimately, that work at some point flows back to where BMR hoisting be- gan. "It is a solution that has been de- veloped by FLS over many years, and South Africa was the first country to go to those levels and to have such a num- ber of machines installed," Koekemoer said. "The solution is there. The prob- lems of deep shaft mining just need to start in those other areas." Enabling Safety and Savings Another brownfield project reportedly launched by a miner seeking to count- er the effects of dwindling reserves is the Onaping Depth nickel-copper pro- ject in the Sudbury Basin. There, Glen- core is investing $700 million into de- veloping a precedent-setting all-electric mine, accessible from a pre-existing mine's infrastructure and targeting 14 million mt of nickel ore situated roughly 2,500 m down. The project has received heavy press coverage, with a focus both on the pro- jected depth and the hypermodern tech- nologies expected to be deployed there. Most recently, Nordic Minesteel Tech- nologies Inc. (NMT) was contracted to "provide all of the shaft equipment, to in- clude skips, cages, safety arrestors, catch gear, as well as all of the required wire rope sheaves for sinking production and A mining flow diagram for both mines at the Mopani Deeps Project in Zambia. (Image: FLSmidth)

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