The miners became trapped at a mine in the border state of Coahuila on Aug 3 when their excavation work caused a tunnel wall to collapse, triggering flooding in parts of the underground mine.

In a statement Thursday evening, Mexico’s attorney-general’s office said it had requested a judicial hearing in Coahuila to charge the mine’s alleged owner for “illicit exploitation” of a state asset, citing his “failing to comply with the law’s obligations” for coal mining.

Mexican officials had also managed to dramatically reduce water depths that initially had topped about 30m, but have struggled to send in rescue teams even on preliminary efforts to gauge whether conditions would be safe for a rescue mission.

Two military divers entered one of the three flooded mine shafts on Wednesday after a miner and a rescue professional submerged four times to clear debris, but were unable to fully enter the mine.

“It had been blocked,” defence minister Luis Cresencio told a news conference on Thursday.

“There is no space to move forward, there are obstructions … there are still some planks of wood. Even with their lights to see inside, they don’t have the necessary visibility to identify what they’re finding,” Cresencio said.

Cresencio added that officials would continue efforts to attempt to enter the mine while ensuring the safety of rescue teams. The water depths in the three shafts measure about 9m, 7m and 5m.