When working with small drivable milling machines (less than half lane) on asphalt, concrete, and other materials containing silica, it's crucial to be aware that this activity can produce respirable crystalline silica dust. Inhaling these tiny silica particles over time can lead to irreversible lung damage.

To address potential exposure, WorkCover Queensland recommends the following controls 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):

Use suitable engineering controls

Consider the following engineering control option:

• Wet cutting machines equipped with supplemental water supplies designed to suppress dust, combined with the use of surfactant in the water.

When using a small milling machine (width less than one lane), ensure the machine is equipped with a supplemental water spray system. The water sprayed should be combined with a surfactant.

Supplemental systems utilize a pump to deliver water (with surfactant) to the milling surface and conveyor, effectively combining with dust and silica particles to reduce airborne levels.

The keys to effective dust control include:

• Water pressure and flow rate.
• Proper application of water combined with a surfactant.
• Nozzle location and orientation.
• Controlling droplet size.
• Selecting the best spray pattern and spray nozzle type for the operation.
• Correct maintenance of nozzles and water spray application equipment.

Operate and maintain the machine to minimize dust emissions.

Select appropriate respiratory protective equipment (RPE)

The type of respiratory protective equipment (RPE) needed depends on:

• The chosen engineering controls.
• The duration of the task during the shift.
• The location of the work.

RPE is not required for the use of small milling machines (less than half lane).