In two of these events, people were in close proximity to the explosions and in one of these a tradesman was sprayed with acid, although he did not suffer any injuries.

The batteries were installed in mobile and fixed plant applications.

In three events, the batteries were sealed “maintenance free” units, and in the other event a vented “maintainable” battery was involved.

Three of the events occurred while maintenance activities were in progress on the equipment.

In events where the battery cases actually failed, debris was scattered up to 10m from the equipment.

“Mine operators should ensure that only suitably competent workers undertake maintenance, inspections and fault-finding on battery installations,” the MSU said.

“Mine operators should ensure that battery enclosures on plant and equipment are kept closed and secured at all times other than when battery inspections or maintenance are being undertaken.”