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only six months, the company delivered the machines to Ecuador, then trained the Chinese operators on site, as well as carrying out on-site modifications necessitated by another change in the project design. Sandvik's Newest Narrow-vein Rig As noted in the October 2013 edition of E&MJ; (pp. 52-53), Sandvik took the opportunity provided by its customer day the previous month at Tampere, Finland, to introduce its latest development jumbo for the narrow-vein mining market. Tracing its heritage back to the Secoma Quasar of the late 1980s, the new DD211 is an electro-hydraulic rig which, the com- pany said, features safety upgrades from the previous model and more automation for increased production. Speaking at the launch, Johannes Välivaara, product manager for under- ground development drills at Sandvik Mining, said that the DD211 has been developed primarily for the Latin America, North America and CIS mar- kets, and has the same key safety and productivity features as the rest of the company's range of drill rigs. "A major feature of this new rig is the Sandvik electro-hydraulic control system, de- signed to enable accurate drilling per- formance in a wide range of rock condi- tions, ensuring efficient control across a variety of operations," he said. "Drilling power is provided through our RD314 rock drill, ensuring not only improved drilling performance and precision, but also reduced drill steel consumption." Sandvik agreed that dilution control is a key challenge in the economics of narrow-vein mining. One of the main aspects in effective dilution control, the company added, is not only to keep the drilling operation efficient and precise but also to plan the charging and blast- ing carefully. "The new DD211 provides a high level of accuracy and control for drilling that helps the subsequent process stages to achieve maximum precision with minimized overbreak," Välivaara commented in an article for Sandvik's Solid Ground magazine. In standard configuration, the DD211 is supplied with a Sandvik SB20 boom, providing maximum coverage up to 26 m 2 . An option is to equip it with an SB20NV boom and CFX 6/12 tele- scopic feed, designed for applications where high levels of maneuverability are required when drilling up-holes and cross-cuts in tight spaces. Measuring 10.7 m long and 2.5 or 2.7 m wide, the carrier has been designed to operate in 2.5 m x 2.5 m headings, with a turning radius of just 2.5 m enabling it to nego- tiate tight curves. Drilling is controlled through Sandvik's THC561 electro-hydraulic system, incorporating constant-speed drilling controls, stop-and-return auto- matics and air-mist flushing with rock- drill return. The company claims that its 110-Hz percussion rate allows the RD314 drill used on the rig to deliver faster penetration and lower consum- ables usage than previous drills fitted to this size of machine. Higher impact fre- quencies also lead to more accurate drilling and hence less dilution, Sandvik added. Compact, at just 559 mm long, the shankless drill is designed to allow the use of longer drill steel within restricted spaces, with hole diameters up to 51 mm (2 in.). "The DD211 incorporates the high- est levels of safety, including a fully ROPS/FOPS-compliant canopy, upgrad- ed braking systems, automatic fire sup- pression and indicator lights for both front and rear jacks," Välivaara said at the launch. "Operator comfort has been further improved through the use of a more ergonomically designed seat, including the ability to turn the seat for drilling. There are also low-effort joy- stick controls." 34 E&MJ; • MARCH 2014 www.e-mj.com N A R R O W V E I N M I N I N G Sandvik's new DD211 is an electro-hydraulic rig for narrow-vein mining. Boart Longyear's StopeMate, which weighs only 3.75 mt, is small enough to fit through a 1.3 x 1.9-m (50 x 75-in.) opening and can fit into a man cage with no disassembly required. EMJ_pg28-37_EMJ_pg28-37 2/28/14 3:10 PM Page 34