The incident in the municipality of Sutatausa, 74km (46 miles) north of the capital Bogota, occurred due to an accumulation of gases that exploded after a worker’s tool caused a spark, Governor Nicolas Garcia told Blu Radio on Wednesday.
The explosion happened late on Tuesday at a series of legal mines that are linked.
“People are trapped between 700 and 900 metres [2,300 and 3,000 feet]” underground, Garcia told reporters. Two people have already been rescued and seven escaped unaided.
Firefighters and other rescue workers could be seen at the entrances to the mines in images from local media, with a handful of relatives awaiting information about their loved ones.
The governor said more than 100 rescue workers were working to free the trapped miners.
“Every minute that passes means less oxygen,” he said.
In a message posted on Twitter, Colombian President Gustavo Petro confirmed that 11 people had died in what he described as a “tragedy”.
“We are making every effort with the government of Cundinamarca to rescue the trapped people alive,” he wrote. “A hug of solidarity to the victims and their families.”
Colombia is home to numerous open and underground gold and coal mines. Incidents frequently occur, mostly at operations that are illegal or do not adopt sufficient security measures.
The most serious recent incident occurred in June 2010, when 73 people were killed in a mine explosion the northwest.
In August, nine miners were rescued from a collapsed illegal coal mine in Cundinamarca.
In 2021, the South American country recorded 148 deaths in mining incidents.
