Vehicle-mounted drilling rigs for rock and concrete
Using drilling rigs mounted on trucks, crawlers or other vehicles to drill into rock or concrete can generate respirable crystalline silica dust. When inhaled, the small particles of silica can irreversibly damage the lungs.
Exposure controls needed in accordance with Appendix 4 of the Managing respirable crystalline silica in construction and manufacturing of construction elements code of practice 2022 (PDF, 1.71 MB) (the Code) when using vehicle-mounted drilling rigs for rock and concrete are explained below.
Step 1: Use suitable engineering controls
Engineering control options (one of the following two controls must be used):
- Dust collection system that has a close capture hood or shroud around the drill bit and low flow water spray that wets the dust at the discharge point.
- Operate from within an enclosed cab and use water for dust suppression on the drill.
Dust collection system
Dust management equipment for vehicle-mounted drills includes a movable duct attached to a close capture hood or shroud around the drill bit, and a flexible rubber skirt that encloses the drill hole opening and captures cuttings that come through the hole.
Air is pulled from inside the shroud through a flexible duct to primary and secondary filter media. The primary filter or dust separator often includes a self-cleaning back-pulse feature that dumps the collected particles to the ground.
Secondary release of particles to the air is minimised by a low-flow water spray at the discharge point. It is possible to retrofit these items.
Dust collection systems are most effective when good design and maintenance practices are implemented by skilled and properly trained operators.
Wet methods
Use an enclosed cab along with applying water to the drill bit during cutting to reduce dust.
Drill operators using vehicle-mounted rigs with enclosed cabs can reduce their silica exposure by staying inside the cab during drilling.
The cab should:
- be well-sealed and well-ventilated using positive pressure
- have door jambs, window grooves, powerline entries and other joints that work properly and are tightly sealed
- have heating and air conditioning so operators can keep windows and doors closed.
- be regularly maintained and cleaned to prevent settled dust from become airborne inside the enclosure.
Step 2: Select appropriate respiratory protective equipment (RPE)
RPE is not required while using vehicle-mounted drilling rigs for rock or concrete.