The cause of an explosion at a Lake Macquarie mine remains unknown, despite being investigated by the state's mining watchdog.
In May 2022, high-pressured air unexpectedly escaped from an air pipe near two workers at the Centennial Coal Mandalong mine, causing an explosion that blew them off their feet.
Both workers were seriously injured, with one transported to Royal North Shore Hospital in the Westpac Rescue Helicopter, suffering spinal injuries.
The metal cap of the pipe was found embedded in the ground 35 metres away. The explosion was so powerful it caused an instant blackout of the work site.
The pair had been working on a nearby water pipe, which had been isolated and all its remaining energy had been dissipated.
Although what happened is well known, why it happened remains a mystery.
Despite a thorough investigation by the NSW Resource Regulator, which included assessing manufacturing specifications, hydrostatic pressure testing and magnetic particle inspection, the explosion's cause could not be found.
"The Regulator determined there was no evidence to establish the failure of the plant to be causally related to the incident," the report stated.
"The investigation also considered human factors but was unable to establish, with any certainty, any causal link to the incident."
Despite being unable to find the cause, the NSW Resource Regulator made several general safety recommendations.
"[These recommendations] should not be interpreted as addressing causal factors related to the incident, which remain unknown," the report stated.
