An accident at a small-scale coal mine project in a northern Mexico border state left seven miners trapped on Friday, officials said.

The Coahuila Labor Department said the mine was apparently hit by some sort of collapse and flooding. The mine, located in Muzquiz township, appears to be a type of deep, narrow, open coal pit with steep earth walls. The area is about is 80 miles (130 kilometres) southwest of Eagle Pass, Texas.

Rescue work was continuing to find the miners. The federal civil defense office said seven miners were missing and that water was being pumped out of the pit to allow rescue work to continue.

The small-scale coal mines of Coahuila have been hit by accidents in the past. A February 2006 methane gas explosion at a coal mine in Sabinas, Coahuila killed 65 miners. Rescuers recovered the bodies of two miners but tons of wood, rock and metal, as well as toxic gas, hindered the recovery of the others.