According to CNN, the mine outside of Sabinas is operated by the company Asociacion de Carboneros BIMSA.

An anonymous official told Reuters it is not yet known if the explosion, which was caused by an accumulation of gas, killed any of the workers.

"At this time we don't know if the 14 miners trapped are dead or alive,” town mayor Jesus Montemayor Garza added to CNN.

“It's going to be a complicated operation because of the way the mine shaft was built," he said, noting that another miner received injuries in the incident.

Garza confirmed to the news service that sixteen rescuers from the Coahuila state civil protection agency were on site at the small operation and another 20 were at the ready to relieve that crew.

However, efforts Tuesday afternoon were being delayed by methane gas in the shaft.

Sabinas, near the Texas border, is in the heart of Mexico’s coal-producing region. The mine is one of many small operations supported in part by the Mexican state and produces coal for power generation.

Reuters said most modern Mexican coal consumption stemmed from domestic supply, though imports had risen there in recent years as coal-fired resources gained in demand.

The country’s worst-ever mining accident occurred in 2006, when 65 workers died in an explosion at Grupo Mexico's Pasta de Conchos coal mine.

Victims’ families are still pushing for efforts to recover 63 bodies still encased in the operation.