Markham Colliery near Chesterfield, Derbyshire, England. A smiling coal miner stands in front of a production table notice, which states target, and actual outputs. It was here, on July 31, 1973, that 18 coal miners lost their lives and a further 11 were seriously injured when a descending cage carrying the men to the pit face failed to slow down as it approached the bottom of the mine shaft.