SUTATAUSA, COLUMBIA (AP) –An explosion caused by accumulated gas in six adjoining coal mines in central Colombia has killed at least 11 workers and trapped 10 below ground, authorities said on Wednesday, March 15.

The explosion took place late on Tuesday in a rural area of Sutatausa, about 75 km (46 miles) north of Bogota.

Two people had already been rescued and seven escaped unaided.

The wife of one of the rescued miners told local media her husband had spent six hours trapped before being rescued.

“We are making every effort with the government of Cundinamarca to rescue the people who are trapped alive,” President Gustavo Petro said on Twitter. “A hug of solidarity for the victims and their families.”

The mines were authorized to operate, the national mining agency said.

Serious accidents are common at open pit and subterranean coal and gold mines in Colombia, mostly at illegal or informal operations and those without proper safety measures.

The most serious recent accident occurred in June 2010, when 73 people were killed in a mine explosion the northwest.