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NARROW VEIN ing out headings. The maximum weight attachment is 150 kg (330 lb), according to Brokk—light in terms of other drilling or mucking systems, but still effective in situations where narrow headings are needed to minimize dilution. There is also the potential for using a breaker, not only for scaling, but also for selective mining, especially where high-grade ore is held in very narrow zones. Brokk notes that although the 100 has good reach and power, it folds into a surprisingly compact package, and can be transported in a small truck or trailer. It is also small enough to fit into most mine cages, with only a power supply needed for it to be put to work. Brokk's range now encompasses eight models, all of which are crawler-mounted, have a three-section articulated boom and are remote controlled for operator safety. Specialized LHDs The German company, Hermann Paus Maschinenfabrik, reports that it can provide individual solutions developed specifically for the demands of mining, with its PFL series of LHDs having been used successfully in operations worldwide for many years. The range includes small LHDs for narrow-vein operations, which are also designed for use at high altitudes. The smaller and narrower the gallery, the smaller a machine needs to be in order to stay maneuverable, Paus said, although there still has to be enough room for components and, of course, the operator. The company added that it takes a lot of experience to address these challenges without making too many compromises. Since there are standards to follow (which may be different for different markets), such as safety and a minimum space for the operator, or exhaust gases that require aftertreatment and produce additional heat, this becomes even more complicated. However, with its PFL 8, Paus copes with all of these issues. With a 1.5-mt payload using a 0.8-m3 bucket, the PFL 8 is one of the smallest underground loaders worldwide, although it is built strong enough to withstand tough conditions with poor roadway conditions. Paus points out that even though it is small in size, its 40-kW Deutz diesel engine gives enough power to perform properly, with a maximum tramming speed of 11 km/h. Paus is going to launch an electric-powered LHD for narrow-vein mining at the bauma 2013 trade fair in April—the PFL 12e. The company's general manager, Franz-Josef Paus, pointed out to E&MJ; that electric LHDs will become increasingly common in narrow-vein operations, since they offer a number of advantages over diesel engines. Ventilation requirements is one factor, with electric LHDs being a real alternative where the tramming distance is less than 200 m. In addition, he said, maintenance costs are up to 20% lower than for diesel-powered LHDs, with electric LHDs being more cost-efficient in lifecycle terms than their diesel counterparts. The 40-kW, hydrostatic-drive PFL 12e is equipped with a 120-m-capacity cable drum. With a 1.2-m3 bucket capacity, its payload is 2 mt, while it has a maximum tram speed of 12 km/h. Paus states that both of these machines are maneuverable and compact, but with good operator comfort. All the controls are arranged clearly and are within close reach of the operator's seat. Control is via two joysticks: one for the driving direction and gear shifting, and the other for the boom hydraulics. Both air- and water-cooled Tier 3-complaint engines are available, as are different bucket types, including a sidedump bucket, with optional quick-coupling hydraulics that allow various attachments to be interchanged in minutes. Canadian-designed Drills and LHDs Within its product range, Ontario-based Mining Technologies International (MTI) supplies development and production jumbos, LHDs and mine trucks that are suitable for use in narrow-vein operations. The company's eight-model LHD range includes four diesel-engined machines that have capacities of less than 2.5 yd3 (1.9 m3), equivalent to payloads of between 700 kg and 3.6 mt. The LT-70 is the smallest, with a 0.5-yd3 bucket and a hydrostatic powertrain. MTI claims that the operator cab fitted to the LT-70 is the largest in this class of machine, while the long wheelbase gives better stability in rough underfoot conditions. The company's other small LHDs include the LT-210, LT-270 and LT-350, which carry 1–1.25-yd3, 1.5-yd3 and 2.5-yd3 buckets respectively, with payloads of 2 mt, 2.7 mt and 3.6 mt. All of these feature a mechanical powertrain. In terms of longer-distance haulage, MTI also has an eight-model mine truck portfolio, of which the DT-704 and DT-1604 would be best equipped for working in constrained areas. The DT-704 has a 6.3-mt payload in a 3.3-m3 (4.3-yd3) body, while the larger DT-1604 carries 14.5 mt and has an 8-m3 (10.5-yd3) body. The company can also supply low-profile and ejector-type dump bodies for use in restricted-height applications. All of its mine trucks are four- While the PFL 8 is one of the smallest LHDs available today, it is built to withstand the rigors of narrow-vein operations. 34 E&MJ; • MARCH 2013 www.e-mj.com