British collieries, the Royal Commission was formed, reporting back in 1907, 1909 and 1911. The reports led to the Coal Mines Act 1911, which came into force in December that year. Among other changes to the health and safety culture, the act required that ventilation fans in all collieries be capable of reversing the air current underground; this measure was to be implemented by 1 January 1913. In 1913 the colliery was producing 1,800 long tons (2,000 short tons) of coal a day, and Senghenydd's population had grown to just under 6,000. No work was undertaken at Senghenydd to implement the requirement, and the Mines Inspectorate gave the management an extended deadline of September 1913 to complete the work, but this, too, was missed. 14 October 1913 At 3:00 am on 14 October 1913, the day firemen descended the pit to conduct the daily checks for gas; they had three hours to complete their investigations. The firemen for the Mafeking return had to travel more than two miles from the shaft bottom to the workface. It left insufficient time in which to make a thorough check of the workings—which involved placing a naked flame into cavities to see if the flame lengthened—the historian Michael Lieven states that "the company considered any other form of inspection to be too time-consuming". Between 5:10 and 6:00 am 950 men descended the shaft for a shift that was due to last until 2:00 pm. Just after 8:00 am an explosion occurred in the west side of the underground workings. It is possible there were two explosions as survivors stated a smaller explosion preceded the main one; the official report referred only to one. The cause was probably a build-up of firedamp that was ignited by an electric spark from equipment such as electric bell signalling gear. The initial explosion ignited airborne coal dust, and a shock wave ahead of the explosion raised yet more coal dust, which also combusted. Many victims who were not killed immediately by the explosion and fire died from the effects of afterdamp. The explosive wave travelled up the Lancaster shaft to the surface, destroying the headframe; it killed the winder—the man in charge—and badly injured his deputy. Edward Shaw, the colliery manager, was on the surface and the remaining shift foremen were still underground and unable to give assistance. He took charge and descended the York shaft, accompanied by