Influence of percussion and rotation pressure on the performance of drilling steels in different types of rock in an underground mine, Peru

Abstract This study evaluated the influence of percussion and rotation pressure on the performance of drilling steels in sandstone and granodiorite rocks in an underground mine in Peru. Using an experimental design, the Shapiro-Wilk test was applied, revealing a non-normal distribution of wear and efficiency data, leading to the use of robust multiple linear regression for analysis. In granodiorite, with percussion and rotation pressures of 130 and 160 bars, respectively, wear and efficiency were higher compared to sandstone, which used average pressures of 80 and 35 bars. Wear in granodiorite reached 3.7 mm on the drill body and 2.4 mm on the inserts, with an efficiency of 2.31 m/min. In sandstone, wear was 2.45 mm and 1.15 mm, respectively, with an efficiency of 1.92 m/min. The drilling steels showed better performance and lower cost in sandstone (0.35 US$/m) compared to granodiorite (0.40 US$/m). It was concluded that both percussion and rotation pressure significantly influence the wear and performance of drilling steels, increasing wear but improving efficiency with each 1-bar increment.