An ATH 12 Secom a jumbo fitted with a single RPH 200 hydraulic drifter was used to drill blast holes 3.6 m(8 2 ft) long by 4.4 cm(134 in) in diameter The RPH 200 drifter is designed to drill holes 3.19 to 4.4 cm(1% to 13/4 in) in diameter for production holes and 8.9-cm(31/2 in) in diameter for cut holes with water flushing. The hydraulic drifter generated no mist. The noise level was 105 dB at 0.9 m(3 ft). Drilling rates were generally good, to 3 m/min(5 to 10 ft/min