(Bloomberg) -- The remainder of workers stuck underground for days over a union dispute at Gold One International Ltd.’s Modder East mine in South Africa have returned to the surface.

More than 540 workers failed to leave the mine after their Sunday night shift ended, with the company describing a “hostage situation” unfolding the following day. The Association of Mineworkers and Construction Union maintained the action was a sit-in protest due to Gold One’s failure to recognize the labor group despite its claim of having a majority of employees as members.

“Everybody got out,” said Jonathan Hericourt, the chief executive officer of New Kleinfontein Gold Mine, which manages the operation. The mine has recognized the National Union of Mineworkers for more than a decade. AMCU said it’s met the criteria needed to hold similar status and threatened to strike over the matter. 

The company and police will hold separate processes “down the road” to investigate any wrongdoing that occurred during the incident, Hericourt said. “We just want everyone to vacate the mine.”

The dispute sees a return of volatility in South Africa’s mining sector, particularly among labor groups. The historically dominant NUM started losing members to AMCU more than a decade ago, highlighted by a strike led by the upstart union at Lonmin Plc’s Marikana operations in 2012 that led to 34 people being shot by police in a single day. 

Before the mass exit of miners at Gold One, a number had forced their way out, Livhuwani Mammburu, a spokesperson for NUM said by phone. 

A group of 13 workers found an alternative exit after days of being trapped by the protesters, who refused to allow them to leave, said Alta Janse van Rensburg, whose fiance was among them and declined to identify him for his safety. “They were lying when they said everybody’s staying down there out of free will,” she said.

“The miners underground broke all the lockers open to get anything there that they could eat,” Janse van Rensburg said. “Apparently some food was sent down, bread, but you know, everybody’s grabbing it. So if you do not stand in front, you won’t get any.”

AMCU General Secretary Jeff Mphahlele earlier Wednesday denied that the workers were held against their will.

“We still maintain this was not a hostage situation,” he said in an interview with Johannesburg-based radio broadcaster SAFM. “This was a concerted effort of workers and members that were working night shift.”

--With assistance from Amogelang Mbatha.

(Updates with escapee account from seventh paragraph)

©2023 Bloomberg L.P.