Engineering & Mining Journal

SEP 2017

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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HAUL TRUCKS 32 E&MJ; • SEPTEMBER 2017 www.e-mj.com Ultra-class trucks have now been around for almost two decades, a timeframe am- ple for meaningful reflection. Beyond the data, there are now plenty of case studies and stories to consider that can make the case both for and against their deploy- ment. A couple of mining engineering pro- fessors from Canada said after glancing back it becomes apparent the ultra-class hauler does have its place, which is also to say that there are mines where it defi- nitely doesn't belong. A handful of vari- ables determine which is the case for a particular mine. Where they diverge is if there is now a trend at play reflecting this reality and what that trend looks like. In a lecture at Haulage and Loading 2017 on his study, Is Bigger Still Better? Considerations for Increasing the Size of Haulage Equipment, Dr. Tim Joseph, University of Alberta mining engineering professor, pinpointed the late 20 th centu- ry as the dawning of the age of ultra-class haulers. The zeitgeist was "bigger has to be better," he said. "We saw a lot of people from the industry pushing to see bigger equipment. Everybody had the thought that if we went bigger, our costs would drop." The resulting push teetered on reck- lessness, he said. "We made a huge leap of faith at that time. We jumped from 240-ton class suddenly to 320 and 360," he said. "We'd come from jumps of 20 to 30 tons. Suddenly we jumped 100, 120 tons in one go." In retrospect, at certain mine sites that faith was redeemed, Jo- seph said. A handful of factors made big- ger better. Those same factors also made bigger more problematic than beneficial at others. "Overall, I still believe that bigger is better because you are able to do more relative to the actual ratio of the pay- load to the gross vehicle weight," Joseph, who is also director of the Alberta Equip- ment-Ground Interactions Syndicate, said in an interview after the lecture. That be- lief comes with a caveat, he said. "It be- comes a function of how big the mine is." Dr. Anoush Ebrahimi, principal mining engineer at SRK Vancouver and author of The Evaluation of Haulage Truck Size Ef- fects on Open Pit Mining (2004), agreed. "In theory, bigger is better if we can man- age the side effects," he said. Ebrahimi, who teaches mine planning and design at Sunrise or sunset for the era of the ultra-class hauler? The bigger trucks hit the market in the upswing of a commodities super cycle and now, after the bust and the bottom, the economics of ownership are on the books for review. Experts agree on factors favoring bigger trucks, but diverge on outlook. Above, a hauler casts long shadows. (Photo: Liebherr) HAUL TRUCKS Jesse Morton, Technical Writer see different futures for the world's biggest haulers Two mining engineers review lessons from a manufacturing 'leap of faith' and Is the Ultra-class Truck Dream Dead?

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