Engineering & Mining Journal

MAR 2013

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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BAUMA PREVIEW 2013 Technology—Mining and Mineral Sciences Laboratories (CANMET-MMSL). Ventilation represents a huge cost for underground mines. With a ventilation rate of around 30 cfm/hp, the Tier 4i engines deliver the maximum ventilation rate available for a conventional diesel engine. According to Volvo Penta, it doesn't get any better. Volvo Penta opted for selective catalytic reduction (SCR) technology to comply with current and future emission legislation. Since Volvo Penta introduced its first SCR engines in 2006, the benefits for the users have been increased power and lower fuel consumption by 5% to 10%, according to the company. And since the catalytic converter was designed to last the life of the engine, the Volvo Penta SCR systems have not increased service intervals or caused any additional downtime. Aker Wirth Unveils Boring System for Development Working with Rio Tinto, Aker Wirth has developed a new, innovative tunnel boring system for underground tunneling and mining—the Mobile Tunnel Miner 6 (MTM 6). The machine concept combines the flexibility of a roadheader with the robustness of a tunnel boring machine. The knowledge gained from a previous version developed by Aker Wirth and tested by Codelco was used to make further improvements to the system. The self-propelled machine moves on a crawler and a walking mechanism and excavates rock with six powerful hydraulically actuated arms fitted with disc cutters. The muck is conveyed to the rear of the machine by a loading apron with loading disks and via a chain conveyor where it is loaded. This new tunneling system is part of Rio Tinto's Mine of the Future program and will be tested in a full-scale trial at the Rio Tinto Northparkes copper mine in Australia this year. The machine should set new standards for mine development. When compared with conventional drill and blast operations, the MTM 6 is designed to more than double current performance with a potential advance rate of 10 m/d. With undercutting technology, the MTM 6 is especially efficient with tunneling in hard rock (up to max. 300 MPa). The considerably lower tensile strength of the rock (as opposed to high compressive strength) is exploited. The roller cutters are positioned at a slight angle to the cutter arms, thus undercutting the rock and removing pieces about the size of the palm of a hand. The energy required for undercutting is about half that used for conventional disc cutters on traditional tunnel boring machines. The MTM 6 is able to cut rectangular or horseshoe-shaped cross-sections in addition to circular tunnels with a bore diameter of up to 6 m. This permits the direct boring of the desired tunnel shape, whereas the lower part of a round cross section usually needs to be backfilled where a conventional tunnel boring machine is used. The machine is also an innovation in terms of its mobility: it can move flexibly forward using a walking mechanism and backward with a crawler. Thanks to several swivel joints, the turning radius of the 75 m long machine is 30 m. This means it can master considerably tighter curves than a classic tunnel boring machine that has a turning radius of approximately 500 m under comparable conditions of use. The MTM 6 combines a roadheader with a tunnel boring machine. 52 E&MJ; • MARCH 2013 "We will revolutionize safety and efficiency in underground mining with the new Mobile Tunnel Miner," said Einar Brønlund, CEO, Aker Wirth. "This innovative technology will improve health, safety and environmental protection significantly and makes working conditions more attractive." Ground Engaging Tools from Spain The Spanish ground-engaging tool manufacturer, MTG recently built a new plant located in Monzon. "What makes this factory so special, besides being equipped with the most innovative technology in melting manufacturing, is the special equipment that allows us to control the steel alloys to an optimum and makes it possible to produce bigger wear parts for mining and heavy construction without the risk of breakage or damage," said Raul Rico, industrial operations vice president, MTG's. The plant has been specifically oriented to expand the company's available product range toward larger mining and heavy construction wear parts. MTG will continue to operate its existing plant in Barcelona. During bauma, the company will display its new MTG ProMet II, which has one single upper base instead of two, allocating more wear material in the front part of the shroud and increasing its wear life, improving penetration, and extending the bucket life. Each new ProMet II size is available in three formats for the bucket lip: central, left and right, with specific angles designed to cover the needs of the main markets. However, new designs and references might be developed in the future to cover other markets' specific needs. The company has also developed an iPad app for selecting wear parts. MTG will launch the new version (2.0) at bauma, which the company claims will be more interactive and better organized with a wizard tool to help users configure their buckets with MTG's teeth and adapters. MTG's ProMet II ground engaging tools. www.e-mj.com

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