At least 60 people were killed on Monday in an explosion at a make-shift gold mine in a village near Gaoua in south-west Burkina Faso.
Dozens more people were injured, including women and children.
It happened as explosives stored near a gold panning site blew up, local officials and witnesses said.
Most of the injured people were evacuated to the Gaoua regional hospital.
A regional prosecutor who visited the scene said an investigation had been opened into the tragedy.
Accidents are frequent at unauthorised mining operations in some African countries, with safety regulation often minimal or non-existent.