Regulator issues safety alert over opal field safety

SafeWork SA recently issued a safety alert about the dangers of fossicking in mining areas following an incident in which a hobbyist was seriously injured when he fell down a disused mine shaft last month.

The man was using a specialised black light torch that illuminates opal at night, when he fell into a disused mine shaft near Coober Pedy.

He fell 25 metres, breaking a leg and dislocating his shoulder. The man was rescued the following night and airlifted to Adelaide after being trapped in the mine shaft for about 22 hours.

SafeWork SA and the Department for Energy and Mining are warning workers, contractors and other persons of the dangers of unmarked, unprotected or concealed mine shaft openings.

Open mine shafts and smaller drill holes can be found in any mining claim area and are a particular risk in opal mining fields.

If entering a mine field, the alert said to notify someone of where and when you are going and plan how to alert emergency services if you need to call for help.

There are many risks involved with entering mining claim areas, according to the safety alert:

Prevent stepping near a mine shaft edge: Ground instability and collapse can occur when weight is placed on the shaft edge: mine shaft edges can be eroded by rain, creating instability just under the edge of the hole around the top edge of the mine shaft.

Never walk backwards: look where you place your feet. Do not stand close to a mine shaft edge, as there is a real risk of collapse.

Don’t walk on a covered mine shaft: mine shafts can be covered with sheets of corroded corrugated iron or thin metal mesh, spinifex, excavated dirt (also called mullock heap spoil) and other materials. Stepping on any of these can result in falling through and down a mine shaft.

Fossicking or noodling at night increases the fall risk: mullock heaps are mounds of excavated waste dirt. People fossick or noodle in these heaps to find missed opal, sometimes using a black light at night.

Never climb on a mullock heap: climbing these heaps can be hazardous, with a serious risk of sliding to the bottom of a heap and into a mine shaft. Instead, take a bucket of material from the heap and search through it on stable, safe ground. It is recommended to use a thin, long steel rod or piece of wood to test the ground in front of you when walking around the base of the mullock heaps to identify these hazards.

The alert noted caldwell shafts (created by a drill rig that cuts a round mine shaft up to 2m wide and 30m deep) and exploration drill holes (20-40cm wide and pose a leg injury risk).

The alert said to build a raised mound of material around a caldwell shaft opening with star droppers to flag off the danger zone when it is not in use, closed or abandoned, as it must still be identifiable. 

“This is the only effective control measure to prevent a fall into the mine shaft. Thin non-supportive mesh is ineffective in avoiding a fall and shaft openings should also be shored to prevent edge erosion,” the alert said.