A PCBU must manage risks associated with excavation work in accordance with the WHS Regulations (r 305) and comply with the trench requirements (r 306): a PCBU proposing a trench at least 1.5 metres deep must, so far as reasonably practicable, secure the work area against unauthorised access and minimise the risk of collapse by adequately supporting the sides by benching, battering or shoring (shielding or other comparable means). Where specific controls are prescribed they must be in place before work proceeds. Practical measures include barricading or para webbing, backfilling as soon as practicable, keeping others away and barricading unfilled trenches after hours. The model Code of Practice: Excavation work gives detail.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.