A French company has provided equipment to assist in the task, she said, without naming the firm.
Coahuila, Mexico's main coal-producing region, has seen a series of fatal mining accidents over the years.
Last year, seven miners died when they were trapped in the region.
The worst accident was an explosion that claimed 65 lives at the Pasta de Conchos mine in 2006.
Only two bodies were retrieved after that tragedy.