A coronial inquest has heard the risk level within a section of the Mount Lyell mine was escalated less than three hours before a mud rush claimed the life of a worker.
Michael Welsh was killed while operating a loader in January 2014 when it was inundated with 1500 cubmic metres of mud, rocks and water.
He was employed by Barminco who had been a contractor at the mine from September 2013.
Copper Mines Tasmania, the owner, would give Barminco mine specifications which would navigate the company’s ore production.
Mine geologist Andrew Forshaw submitted a hazard report at 5.30am that morning for the traverse drive Mr Welsh would work within.
Using information from the night shift supervisor’s observations, the risk level within TD-14 was elevated from a monitoring level to medium; the third highest on a risk scale.
Mr Welsh was uncontactable by radio from 8am which triggered an inspection from technical services superindependent Clint Mayes, who was second in charge at the mine behind the mine manager.
Mr Mayes said he went to a traverse drive next to TD-14 and waded through mud he described as hot, thick and three feet deep until he reached the Mr Welsh, facedown and unresponsive.
He said he was aware of issues within TD-14 prior to the incident but there were “no real alarms or red flags” and everything that needed to be done of the section of mine classed a medium risk of mudslide was complied with on the day.
Mr Mayes said that particular section was a high priority drawpoint for ore.
He said there were two levels in production at the time but three levels was ideal so as to give sections of the mine time for maintenance and rehabilitation.
Mr Mayes said drawpoints on TD-14 required rehabilitation.
He said there was concern over bulging in part of that section which indicated an increased level of fine materials and water.
Mr Mayes said if a driver wasn’t happy with the condition of a particular drawpoint, they were free to stop working on it, barricade the area, and raise the issue with the shift supervisor.
Mr Mayes said once the Mount Lyell could be reopened, the sub-level cave mining technique used at the time of the three deaths would be replaced by technique that reduced mudslide risks markedly.
He said the maintenance task which lead to the falling deaths of miners Alistair Lucas and Craig Gleeson in 2013 would no longer need to be performed under the new method.
The inquest will continue for the rest of the week.