September 10, 2026
A US investigation into the death of Joshua “Josh” Mock reveals how a series of equipment, maintenance and communication failures ended in tragedy at Acosta Deep Mine in Pennsylvania.
Josh was 34 when he was killed on 10 January 2025. He had worked at the mine for one year and nine months and had received all required training for his role.
Josh was operating a mobile bridge carrier—part of a connected underground system that transports coal from a continuous miner to a conveyor belt.
The left track on Josh’s carrier broke while the connected system was being repositioned. When the continuous miner at the other end was moved away from the belt structure, that movement travelled through the connecting conveyors and pushed Josh’s disabled carrier towards the coal rib.
Josh was partially outside its operating compartment and was fatally pinned.
The investigation could not determine why Josh was partially outside the compartment or whether he had activated an emergency stop.
What investigators did establish—and what their final report makes unequivocal—was that mine operator Wilson Creek Energy was at fault.
Mine management had instructed workers to connect two different models of mobile bridge carrier despite knowing their electrical systems were incompatible.
Investigators also found an unauthorised device had been installed in the system. When connected, it disabled the emergency-stop switches on the carriers and prevented the continuous miner from shutting down.
Connecting and disconnecting this device had become common practice.
Investigators found other unauthorised modifications capable of defeating safety circuits, along with a broader pattern of improper maintenance.
The mine also had no procedure requiring operators to communicate their positions and intended movements before the connected machinery was moved.
Investigators concluded that Wilson Creek Energy failed to maintain the system’s electrical components in a safe condition and failed to provide adequate communication procedures.
US authorities described the company’s actions as “aggravated conduct constituting more than ordinary negligence” and an “unwarrantable failure” to comply with a mandatory safety standard.
The mine’s new owner has since removed the carriers involved from service and introduced equipment with compatible electrical systems, along with new requirements for communication and de-energising machinery.
We extend our deepest sympathy and solidarity to Josh’s family, friends, community and workmates.
Josh should have come home.