Engineering & Mining Journal

MAY 2019

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Page 45 of 83

UNDERGROUND MINING 44 E&MJ • MAY 2019 Conducting field trials with a mono- rail-mounted jumbo, Torex Gold Re- sources recently drilled and shot the first rounds from its Muckahi mining system. This new mining method, which was con- ceived by Fred Stanford, president and CEO of Torex, combines face drilling and blasting with a slusher that feeds ore into a set of conveyors. The entire system has been designed to operate on a monorail system attached to the back on a steep (30°, 58%) incline in a narrow heading. Based in Canada, Torex is an interme- diate gold producer engaged in the ex- ploration, development and operation of its Morelos Gold Property in the Guerrero gold belt located 180 kilometers (km) southwest of Mexico City. The company's principal assets are the El Limón Guajes (ELG) mining complex, which consists of the El Limón, Guajes and El Limón Sur open pits, the ELG underground mine, and a processing plant with related in- frastructure; and the Media Luna ear- ly-stage development project. The com- pany plans to implement the Muckahi mining method at Media Luna. Torex believes the Muckahi system will reduce capital expenses related to underground mining by as much as 30%. It also expects a 30% reduction in operating costs. The system could decrease the time between investment and revenue considerably. In fact, Torex has calculated a 46% after-tax internal rate of return (IRR) on capital vs. 27% after-tax IRR for conventional mining with LHDs and trucks. The question that led to its develop- ment: Why would anyone want to run a logistics business on single-lane roads? With that in mind, Torex began work- ing with Medatech, an engineering firm based in Collingwood, Ontario, to de- velop a system that would continuously mine and transport ore from the stope to the shaft (or the surface). Essentially, the technology developers were tasked with designing a two-lane system that operates in a tunnel half the size of a conventional heading. In addition to transporting ore and waste away from the face, it would also have to transport personnel and supplies to the face. The major upside to the Muckahi sys- tem is that the decline tunnels would be four times as steep and therefore ¼ the length of conventional decline tunnels. Smaller, shorter tunnels cost less and of- fer rapid access to ore. The system could also be fully automated and included in an all-electric mine plan, which is a hot topic these days in many mining districts. Initial Test Work Torex is currently training its miners to use the Muckahi system at a test head- ing at the ELG underground mine before they begin development on the Media Luna project. On April 3, the company announced they had successfully com- pleted the first blast. "After so many years in concept de- velopment, machine design, and more recently, machine manufacturing, it was truly rewarding to see this first part of the innovative Muckahi mining sys- tem 'come to life' and perform the way it was expected to perform," Stanford said. "This outcome is a credit to all of the people over the years that believed a different way to mine was possible and contributed ideas and support to trans- form that possibility into a reality. In recent years, this includes our board of directors, Robert Rennie and team from Medatech, and many from within Torex, including Bernie Loyer for machine de- sign and project management, Dawson Proudfoot, Danny Lavigne, and Brian Truman for process design and leader- ship in the field trials." "The team is looking forward to com- pleting the field trials in 2019," Stan- ford said. "The goal is to demonstrate the Muckahi mining system capabilities over the full development cycle for tun- neling, including on a minus 30° gradi- ent, and to demonstrate the capability of the system to lower costs in long-hole, open-stope mining. Exciting times." What they demonstrated was the ability to drill, load and shoot a round off the overhead monorail. They have since shot five or six more blasts. Torex Shoots the First Muckahi Blast Novel underground technique could allow miners to extract ore from steep stopes By Steve Fiscor, Editor The Muckahi system uses a jumbo mounted on a monorail. Power packs (blue units) move the components using the tires mounted on both sides of the monorail.

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