Engineering & Mining Journal

MAR 2016

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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MARCH 2016 • E&MJ; 71 www.e-mj.com S U P P L I E R S R E P O R T impact the penetration rates. After each set of holes was drilled, 6-ft, resin- anchored rock-bolts were installed in each hole drilled by the pneumatic drills, but not in the shorter holes sunk with the Hilti drill. The time to complete this installation was measured. Not surprisingly, Hilti's electric drill produced the lowest average sound level values of all the drills tested: 101.5 dBa. Of the pneumatic machines, Boart Longyear's drill produced the lowest aver- age sound level values at 109.5 dBa— well below the 116.5-dBa average of the older PHQ drill being used at the site and even below the 113-dBa average of the newer PHQ model. The electric Hilti drill also produced the lowest vibration results of all the drills tested and the Boart Longyear produced the lowest vibration results of all the pneumatic machines. The three pneumatic machines were fair- ly consistent in penetration rates at 1.5–1.7 ft per minute, with the S250- M3 posting a slightly higher average pen- etration rate than the PHQ drills. The electric Hilti drill, however, lagged with a penetration rate about one-third that of the pneumatic drills. In addition to the recorded perform- ance data, each driller provided evalua- tions regarding his personal observations of the operation of each drill, including overall ease, noise and vibration. So what did they think of the various drills they tested? Asked to score various criteria on a five-point scale, the miners ranked the S250-M3 highest overall with 26 points out of a possible 35, and high- est for overall ease of use with 18.56 points out of 25. The electric Hilti ranked first for overall noise/vibration with eight out of a possible 10 points and the Boart Longyear drill was close behind with 7.44 points. (See box for the S250-M3's complete score.) The evaluation team noted that despite the electric drill's advantage in terms of sound and vibration rates, its dramatically lower penetration rate compared with the pneumatic drills made it unsuitable for their applications—and they subsequently learned that Hilti would no longer market the TE MD20 drill in North America, eliminating it from further consideration. As a result of the head-to-head testing of the remaining drills—all pneumatic machines—the evaluation team recomend- ed the S250-M3 as its drill of choice for rock drilling. The S250-M3 comes in three primary variations to match specific customer needs—jackleg, stoper and sinker. The drill hex chuck ends are available in both 22 mm and 25 mm. Jared Kessen is senior business develop- ment manager–percussive products (North America) for Boart Longyear . Results from Third-party Testing of Boart Longyear's S250-M3 • Lowest vibration: 20 m/s 2 • Lowest sound production: 109.5 dBa • Highest penetration rate: 1.7 ft/min • Highest overall ease of use rating: 18.56 (25 possible) • Highest noise/vibration perception: 7.44 (10 possible) • Highest overall score: 26 (35 possible)

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