Mine operators in New South Wales are being urged to reconsider the use of a specific explosive device following a tragic incident that resulted in the deaths of two workers. Patrick "Ambrose" McMullen, 59, and Holly Clarke, 24, were killed in an explosion at the Endeavor underground metals mine near Cobar on October 28. The New South Wales Resources Regulator reported that the two were attempting to clear a blockage in a mine cavity using a ballistic disc explosive device when the explosion occurred.

Ballistic disc explosives are typically detonated remotely. They fire a high-velocity steel slug to break apart rock formations, allowing workers to clear blockages without entering potentially dangerous areas. According to the regulator, the workers were in the process of setting up the device when it detonated unexpectedly. The exact cause of the premature detonation has not yet been determined.

The regulator is collaborating with manufacturers, suppliers, and mine operators involved with ballistic-disc type explosive charges as part of its ongoing investigation. It has indicated that it may prohibit the use of these explosive charges if they are deemed to pose a serious risk to health and safety at mine sites.

In light of the incident, the regulator has recommended that mine operators explore safer alternatives for clearing blockages.

Endeavor is one of Australia’s largest mines, producing zinc, silver, and lead. It operated for nearly 40 years before being placed in care and maintenance mode in 2020 due to financial issues. The mine was acquired by Polymetals Resources in 2023 and resumed full operations in June. Currently, it employs over 200 workers, with about 30 present during the explosion. Polymetals plans to restart work at the mine in a phased approach starting next week.

The Cobar community is mourning the loss of McMullen and Clarke. Tributes have been placed at the Cobar Miners Memorial, which honors the names of 171 miners who have died in local mines over the past century. Residents had recently gathered at the memorial during the town's annual Festival of the Miner's Ghost to remember those lost in the mining industry.

Community members described McMullen as a "true gentleman" who positively impacted many lives. Friar Paul Finucane from St Laurence O'Toole Catholic Church noted that the last mining fatality in Cobar occurred in 2017, expressing the community's hope that such tragedies would not recur.

Emergency services worked throughout Tuesday to recover McMullen's body, which was initially buried 700 meters underground. Clarke, who was raised in Cobar and had family ties to the mining industry, was brought to the surface but later succumbed to her injuries. Another worker, 24-year-old Mackenzie Stirling, was also injured in the blast. She was airlifted to Orange Hospital for treatment but has since returned home to continue her recovery.