BOGOTA: Ten workers trapped in a coal mine in central Colombia were found dead, bringing the death toll from an explosion in the pit to 21, President Gustavo Petro said Thursday.

A build-up of methane gas apparently triggered the Tuesday night explosion in the underground complex, according to local officials.

“Sadly, 21 people lost their lives in this tragic accident in Sutatausa,“ a municipality in Cundinamarca department, the Colombian leader wrote on Twitter.

Rescuers had found 11 other bodies on Wednesday in the mine, which is some 45 miles (75 kilometers) north of Bogota.

Cundinamarca Governor Nicolas Garcia also announced the search was over Thursday, writing on Twitter that “unfortunately there is no longer anyone alive. We are heartbroken.”

Dozens of rescuers had searched for the miners in six interconnected legal mines, where officials are now investigating whether there was appropriate air flow.

Sutatausa’s mayor, Jaime Arevalo, had earlier described the rescue effort as “very complex,“ saying oxygen was running out and water was “beginning to accumulate.”

In order for methane not to explode, proper ventilation and monitoring systems allowing for alerts and split-second decision making are needed, Javier Pava, director of the National Unit for Disaster Risk Management, told outlet Canal Institucional.

“It will have to be reviewed if these existed or not,“ he said.

Oil and coal are the main exports of Colombia, where mining accidents are frequent, especially at illegal digs in Cundinamarca and other departments in the country's center and northeast.

Colombia registered more than 1,260 mining accidents from 2011 to May 2022, for an average annual toll of 103 deaths, according to official data.

At least 130,000 people make a legal living from mining in Colombia. - AFP