Thedevelopment ofdrilling andblasting practice atPalabora ...
ROTARY DRILLING EQUIPMENT During the first five years of operation of the Palabora pit, primary drilling wasperformed with six dieselpowered selfpropelled downthehole drilling machines, putting down 22,9cmholes at 150 offvertical. These drillsweregradually phased out and replaced with modern electric rotary drills capable ofdrilling up to ...