In what part of Mexico is coal mined?

Most of the coal in Mexico is concentrated in three widely separated regions. Coahuila on the northeast, Sonora on the northwest, and Oaxaca on the south southeast.

Coal mining in Mexico. Industrial coal mining in Mexico first dates to the year 1884 at the Sabinas basin, in the northern border state of Coahuila. The vast majority of the nation's known reserves remain in this relatively small Región Carbonífera.

Do you have more info about it ? i doubt this is the answer because i don't have all the information but if trouble was brewing in a clinic maybe it was an argument as to which clinic was better or smth of that nature