Mining Publication: Assessment of Airborne Dust Generated From Small Truck-Mounted Rock Drills

• Drills
• Dust collectors
• Wet drilling

Dust surveys were conducted around small truck-mounted rock drills operating at surface coal mines to assess their airborne respirable dust generation and in-service dust control methods. Of four out of seven drills sampled, respirable dust concentrations measured around the drill deck ranged from 8.68 to 95.15 mg/m³ with concentrations ranging from 1.37 to 2.69 mg/m³ at distances 12.2 to 30.5 m downwind of these drills. The other 3 drills had noticeably lower respirable dust concentrations measured around the drill deck at or below 1.30 mg/m³. Rotoclone-type dry dust collectors were commonly used with dust being emitted from around the drill deck shroud, collector exhaust, and collector fines dumping. Wind speed and direction was also a factor in the dust concentrations measured on the bench. Dust control modifications were made to three rock drills to reduce their airborne dust emissions. Dust controls tested included water injection into the Rotoclone exhaust, Rotoclone exhaust extension, improved sealing of drilling deck shroud, shrouding the Rotoclone hopper dump process, and wet drilling. These control techniques showed noticeable improvement in dust concentrations measured around the drills. Finally, repositioning the drill operator showed that operator dust exposure can be improved by avoiding the dust cloud around the drill.