The first development was by David Davis of Blaengwawr from 1857, in accessing the high quality steam coal and at a greater depth, he spurred others into tapping into the "Black Gold".
Resultantly, their pit head workings were closed on economic grounds, although the workable underground coal faces were consolidated into the remaining shafts.
It took a month to recover the remains of the 178 men and boys, with most bodies showing signs of severe burning, and many so badly disfigured it made identification impossible.
At the subsequent enquiry, the lamp keeper stated that safety locks had been tampered with, and incidents regularly occurred that breached the company's rules.
Second: by this gas being fired by one or more of the colliers carelessly taking off the tops of their lamps and working with naked lightsJust 17 months later, on 10 June 1869, another explosion occurred killing 53 men and boys.
[3] On 13 February 1908, 55-year-old former Private Thomas Chester, who 29 years earlier had been one of the defenders during the Battle of Rorke's Drift by thousands of Zulu warriors, was killed in the railway sidings of the coal washery at No.5 pit.