The mining watchdog has urged mine operators to reconsider the use of a common explosive device used underground, after the premature detonation of one caused the deaths of two mine workers.

Patrick "Ambrose" McMullen, 59, and Holly Clarke, 24, were killed by an explosion at the Endeavor underground metals mine near Cobar in Western New South Wales, in the early hours of Tuesday, October 28.

According to the NSW Resources Regulator, Mr McMullen and Ms Clarke were working to clear a blockage in a mine cavity using "a ballistic disc explosive device".

Ballistic disc explosives are usually detonated remotely, shooting a high-velocity steel slug that shatters rock formations. This allows workers to clear blockages without having to enter unstable areas.

"Workers were in the process of sett

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