Background
Since 2018, mines inspectors have raised many defects and notices related to the poor condition of accessway grating in plants at more than 60 mines. This is notable around sumps and drains, above leach tanks and in saline environments. Gratings are often corroded, deformed, inadequately secured and/or incorrectly installed. Grating supports are frequently cracked, corroded or missing.
Summary of hazard
Poor installation or maintenance of accessway gratings and their supports may result in:
- a worker falling with potential for serious or fatal injuries. The fall can expose workers to other hazards including drowning, harmful atmospheres and hazardous materials
- the grating dislodging and falling onto workers below with potential for serious or fatal injuries.
There is also an increased risk of failure of the accessway or platform during maintenance activities when point loads associated with scaffolding or specialist equipment are in use. This exposes multiple workers to the hazards.
Contributory factors
- Inadequate inspection and maintenance of accessways contributes to the poor condition of gratings and potential failure.
- Potential for failure is significantly increased when the load bars are damaged or corroded adjacent to a support or at midspan.
- Poor design and detailing of accessway, platform gratings and their supports may accelerate the deterioration of the grating, its fixings and supports.
- Corrosive environments associated with salt, acids and solvents, as well as regular exposure to moisture, accelerate the deterioration of steel gratings and supports.
- Ad hoc modifications and addition or removal of penetrations to accessways may cause the grating or its supports to be overloaded.
- Grating that is subject to vibration or lateral loads (e.g. on plant, ramps or adjacent to crushers) may not be suitable for fixing with screw or bolted fasteners.