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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UNDERGROUND HAULAGE Underground Rock Handling E&MJ; looks at some recent developments in both traditional and unconventional systems for moving rock in underground mines By Simon Walker, European Editor High-tonnage underground mines can benefit from using a fixed rail-based transport infrastructure, as at LKAB's Kiruna operation. (Photo courtesy of Schalker Eisenhütter) In many respects, the choice of haulage system for an underground mine is dictated by the orebody geometry. Narrowvein systems or orebodies that are elongated vertically lend themselves to an LHD-based system centered around a series of orepasses. For ore zones that are more tabular, or are geographically spread out, using LHDs to load mine trucks that then transport material either to an orepass or directly to surface via a ramp may be a better option. High-capacity, bulk-tonnage mines, by contrast, may find that a fixed infrastructure network using either high-tonnage trucks or rail-bound haulage is the most economical way of moving their ore. And, while conventional belt conveyors are less-commonly used in hard rock mining than in coal, for instance, there are always innovations being developed and trialed that offer an alternative means of rock transport. In this article, E&MJ; samples some of the recent technological developments in each of these areas, showing just how versatile the various systems now available can really be. 56 E&MJ; • JUNE 2013 Locomotive Haulage: Still a Major Option Earlier this year, German specialist locomotive manufacturer Schalker Eisenhütte Maschinenfabrik announced it had won a further order from Sweden's LKAB for heavy-duty mining locomotives. With three out of an initial five of the 108metric ton (mt) machines already delivered, and two scheduled to arrive in northern Sweden this year, the new order brings the total number of locomotives Schalke will be supplying to LKAB to nine. Specially designed and tailor-made for use at the new 1,365 m level at the Kiruna iron ore mine, the trolley-wire locos can handle a non-braked load of up to 1,500 mt per train from the loadout to the primary crushing station. Schalker has also equipped them with technology that allows fully automated operation throughout the complete loading, haulage, dumping and return cycle. With each wheelset being powered by a 225-kW, IGBT-controlled AC traction motor, the locos feature electrodynamic service braking that uses dynamic retarding to bring the train to a complete standstill. An automatic train protection (ATP) system provides for additional safety during operation, even at haulage speeds of up to 25 km/h, Schalker said. Meanwhile, during 2012 the company received an order from FreeportMcMoRan Copper & Gold (FMCG) for 10 40-mt mining locomotives for the Grasberg mine in Indonesia. With the transition from open pit to underground mining, FMCG has been developing a "common infrastructure" network that will handle all of the production from the DOZ, DMLZ, Big Gossan, Kucing Liar and Grasberg block cave operations from 2017. The Schalker locos will be used to transport all production from the mining areas to the treatment facilities, with the first units scheduled for delivery next year. Two-axle, compared with the fouraxle LKAB locos, the FMCG units will be powered by a 135-kW AC traction motor on each wheelset. A fully loaded train will run to just more than 700 mt, with haul speeds of up to 25 km/h. www.e-mj.com