The Gresford Disaster occurred on 22 September 1934 , when 266 men died following an underground explosion .
Gresford Colliery was the site of one of Britain 's worst coal mining disasters .
The Gresford Colliery   occurred on 22 September 1934 , when 266 men died following an underground explosion .
Gresford Colliery was the site of one of Britain 's worst coal mining disasters .