CARLETONVILLE, South Africa – Singing and dancing despite exhaustion, the last of 3,200 miners trapped deep underground for more than a day emerged safely Thursday night, delivering a happy ending but raising questions about the safety of South Africa’s important gold mines.

Government officials announced that the Elandsrand mine, one of the top producers in the world’s leading gold-mining nation, would stay shut for at least six weeks while experts studied what caused a pipe to break and crash down the main shaft Wednesday, knocking out the elevator.

The National Union of Mineworkers threatened unspecified “industrial action” against the mining business, accusing managers of earning fortunes while compromising on safety. It said that among other things, companies have let alternative escape routes flood rather than maintain them.

The final group of 45 workers brought out through an auxiliary shaft normally used to remove debris arrived at the surface shortly before 9 p.m., walking out caked in dust but otherwise healthy a day and a half after the accident.

Amelia Soares, spokeswoman for Harmony Gold Mining Co., said that despite the pipe fall itself and the long hours spent by miners waiting for rescue a mile below the surface, only one health problem was reported – a worker who had to be treated for dehydration.

“We can only be grateful and satisfied that not one single life was lost,” Soares said. “Spirits are high and we are all very pleased.”

Waiting their turn to get out, the miners gathered near a ventilation shaft and the company lowered water and food to them.

The miners were trapped when a pipe carrying pressurized air exploded and tumbled into the elevator shaft Wednesday morning, breaking electricity lines powering the main elevator. Some of the 3,200 men and women stranded had entered the mine for the Tuesday night shift.

A smaller elevator cage had to be rigged to raise the miners out another shaft, and the first group reached the surface about 1 a.m. Thursday. The company had expected the rescue to take 10 hours in all, but it lasted nearly twice that long.

Buyelwa Sonjica, the government’s minister for minerals and energy, said the Elandsrand mine would not be allowed to reopen for at least six weeks while experts checked it. She also said health and safety legislation would be “tightened up.”

Last year, a total of 199 South African mineworkers died in accidents.

Associated Press writers Clare Nullis and Celean Jacobson in Johannesburg contributed to this report