Glencore had already made the decision to close the troubled West Wallsend in mid-2016 – considerably ahead of the approved mine life to 2021 – impacting a workforce of about 300 that includes contractors.

The latest incident now puts further doubt about the short term future of the mine.

A spokesman for Glencore told ICN: “Glencore can confirm that production at its West Wallsend underground mine has been halted due to geological issues experienced on the current longwall operation (LW46) last week. We are investigating a number of options to resume operations as quickly as possible. However, it is expected that production could be affected for some time.”

While Glencore has not revealed much on how long the recovery effort will take and investigations remain underway, at this stage ICN understands that the longwall might not be cutting coal for at least six weeks with plenty of manual shovelling work ahead for workers at the face.

There also suspicions that the collapse may have been linked to a fault in the workings.

West Wallsend mine won state government approval in October to mine two additional longwall panels, LW51 and LW52.

They equated to 2.55 million tonnes run of mine – a little less than the estimated 3Mt ROM that the mine was no longer going to extract following the subsidence impacts the mine was blamed for in the Sugarloaf state conservation area.

At the time these two panels were considered enough to not alter West Wallsend’s existing mine life or approved production capacity of 5.5 million tonnes per annum ROM, with the panels selected after the adjacent Newstan colliery terminated a sublease.

However, Glencore has also considered market conditions when re-assessing West Wallsend’s mine life and decided to cease production in 2016.