The Department of Planning and Environment’s Resources Regulator has released a report into the incident in which two workers were trapped for almost nine hours 162 metres below ground at a Tahmoor Coal Mine near Picton in the Southern Highlands.
Chief Compliance Officer, Anthony Keon said the Regulator’s Causal Investigation into the incident identified several factors that led to the incident on 5 September 2018.
“The workers became trapped when the lift carrying them up to the surface suddenly broke down about 160 metres short of the surface following an earlier collision between the winder counterweight and the side wall of the shaft,” said Mr. Keon.
A Causal Investigation was launched to enable the quick and full understanding of the causes of the incident.
“We set up a team including people from Tahmoor Colliery, Shipping, Infrastructure, Mining, Energy and Commodities (SIMEC), the Construction, Forestry, Maritime, Mining and Energy Union (CFMEU) and the Resources Regulator,” said Mr. Keon.
“The team found the most likely scenario was that the winder counterweight was misaligned, causing it to strike a water ring 240 metres below the surface and ripping it from the shaft wall.
“The water ring became wrapped around shaft services, winder head ropes, and balance ropes, pulling them out of alignment and tripping the winder protection circuit – stranding the workers for more than 8 hours.
“A contributing causal factor was found to be uneven tension on the ropes holding the counterweight which caused it to rotate and come into contact with the shaft wall while it was moving.
“The team also found monitoring of the rope tensions wasn’t fully covered by maintenance and inspection, and some of the early indicators of the problem that caused the incident were not communicated to senior management to action.
“The Resources Regulator has produced a detailed investigation report and animation of the incident and is calling on mine operators immediately to review their safety management systems in light of the lessons learned.”