The death toll from a fire that swept through an iron mine complex in the northern Chinese province of Hebei rose to 57, with three miners still missing, Xinhua news agency said yesterday.

Forty-six of 106 miners on duty when the fire broke out on Saturday morning had been rescued, and emergency workers had pulled most of the bodies to the surface. “Preliminary investigation shows that the fire broke out due to electronic cable self-ignition in one iron mine,” Xinhua said.

The fire at the mine in the Hebei city of Shahe quickly spread to four connecting pits, trapping dozens, many of whom suffocated. Most of the miners were from the southwestern province of Guizhou or Shaanxi province in the northeast, Xinhua said.

China’s mining industry has a grim record, with coal mine disasters reported on a weekly basis. Mines have expanded with little regulation as they strive to keep up with booming demand to help fuel the world’s seventh-biggest economy. China’s worst coal mine accident in years killed 148 miners in the central province of Henan last month.