Ingeominas rescue operations head Fabian Morales told news service Marketwatch that the incident appeared to be related to methane gas.

While the mine’s location was identified by the official as Boyaca, near Bogata, the specific operation name was not available to ILN at press time.

Morales also told the wire that the rescue team was not able to determine Wednesday afternoon how many other miners had been trapped.

The explosion is the latest in a string of fatal mining accidents this year; 106 people have died in the South American country’s operations so far in 2011.

Colombia, which has both surface and underground mines, is the fifth largest coal exporter in the world. Its major player operators include Alabama-headquartered Drummond, Glencore International BHP Billiton and Xstrata.

Earlier this week, Colombian president Juan Manuel Santos said that its energy minister, Carlos Rodado, had stepped down from his post amid increased scrutiny of the country’s growing mining industry and criticism over his leadership skills during a rash of mining fatalities.

He told Reuters that Rodado has been replaced by economist Mauricio Cardenas, a former member of the country’s senior government.

Cardenas is the third new minister to be named in just a month; Santos has recently altered his cabinet members in the midst of major reforms and public scrutiny and pressure regarding mining practices at Colombian operations.

Rodado cited personal reasons for his resignation. Santos has named him to ambassador to Argentina.

Cerrejon president Leon Teicher told Reuters Tuesday that he was optimistic of the improvements Cardenas can make to the country’s industry.

“We all know Mauricio Cardenas. He's an excellent technocrat on the one hand with a very good track record in political appointments,” he said.