According to a Thursday morning Fox News report via EFE, the bodies were brought to the surface of Minera El Progreso’s Deborquez mine following hours of rescue efforts.

El Progreso is in the northern Coahuila state, about 90 miles (150 kilometers) from the US border city of Eagle Pass, Texas.

Emergency services official Juan Antonio Ibarra did not identify the killed miners, but said they ranged between 20 and 39 years of age.

Coahuila state civil defense force head Francisco Contreras Obregon also reportedly told local media the group had been severely burned and crushed by falling rock.

It still is not known if any other miners were able to escape the blast, which occurred at about 9am Wednesday. EFE said the group of men, all from the same family, were digging a ventilation shaft.

“They apparently bumped into one of the pockets of methane gas,” Coahuila public safety secretary Jorge Luis Moran Delgado said.

The explosion was estimated to have occurred between 60 and 70 meters (195-228 feet) underground.

An unnamed federal labor department official told EFE the mine had only been operating for one week and that the owner has been the subject of 16 inspections for violations at other mines.

He said Minera El Progreso was facing sanctions in connection with those other issues.

The Mexican state of Coahuila has many small, primitive operations, and methane is considered a common hazard.

In 2006, 65 miners were killed in a similar explosion at the Piedras Negras mine, also in Coahuila.

Recently, Mexican congress mining committee chairman Miguel Pompa Corella presented a bill to increase coal mine regulations in the country.