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product news Sandvik Upgrades Its Roadheaders An arch-installation platform (left) rides separately above the cutting boom (right) on Sandvik Mining's modified MR341 roadheader. In early February, Sandvik Mining unveiled some major upgrades to one of its mainstream boom-type roadheaders, designed specifically for use in roadway development in coal and soft-rock operations. Building on the long-standing success achieved with the MR340—itself developed from the AM75 Alpine Miner— the new MR341 features extensive design improvements as well as the ability to incorporate an integral support-installation package. Speaking to E&MJ; at Sandvik's competence center for mechanical rock cutting in Zeltweg, Austria, the company's global sales support manager for coal and minerals, Bruno Reumüller, explained that one of the main drivers for the new upgrades has been its goal of improved safety for equipment operators and other development workers. "The MR340 was introduced in the 1980s, and has been the most successful mid-range roadheader produced at Zeltweg. Since then, there have been many upgrades to the original machine, so we took the decision to carry out a major redesign with the development of the MR341," Reumüller said. "We now have an integrated excavation and ground-support system. "Improved safety and the integration of the ground-support module have been 48 www.coalage.com the key features. Our aim has been to reduce the risk of people working beneath unsupported ground during heading development, as well as to cut the amount of heavy manual handling that face crews need to do when installing supports such as steel arches." The MR341 can be equipped for PLC control, which then allows cutting profile control to be included—an important feature where arch support is being used, since both under- and overbreak must be minimized. Automated cutting is also possible if operators require this, as are data acquisition and smart maintenance options. "This may be adding complexity, but it helps to make up for the increasing shortage of skilled operators throughout the mining world," Reumüller noted. With a total weight of 80 mt, the MR341's dimensions are essentially the same as the previous machine. The total length is 11.2 m (36 ft 9 in.) while the width over the cutting table is 5.1–5.8 m (16 ft 9 in.–19 ft) with the apron side flaps either retracted or extended. With a maximum cutting height of 4.87 m and maximum face width of 7.45 m (16 ft and 24 ft 6 in., respectively), it also has a 270-mm (10.5-in.) undercut capability. Where the machine differs significantly from its predecessor is in the bolting, mesh- ing and arch-installation platform that now rides separately above the cutting boom. A hydraulic, 1-mt-capacity arch, hand meshsetting manipulator allows support materials to be lifted along the side of the machine to the face, while the front of the platform carries a single hydraulic rotary drill for rockbolt installation. Other important upgrades include the incorporation of dust-extraction ducts along both sides of the roadheader, with moveable inlets, and improved cut-rock handling. This has moved the chain conveyor drives to the rear of the machine, extended the conveyor to the front of the apron, and produced a redesign of the gathering stars on the apron as well. New square star drives mean that maintenance is easier, Sandvik said. The additional load from the support platform has led the company to change the way in which the undercarriage units are secured to the main frame. Bolting them together provides greater machine stability, Reumüller pointed out, while stronger stabilizers fitted to the track frames enhance this as well as provide better access for undermachine maintenance. Total installed power on the MR341 is 404 kW (550 hp), comprising 200 kW for the cutting motor, 132 kW for the hydraulics motor/pump and twin 36-kW March 2013