the Act's requirement to install reversible fans and to measure underground air currents. The Act stated that fans should operate continuously while colliers were working on the face. Failure to observe this rule was one of the causes of an explosion at Wharncliffe Silkstone in May 1914 that caused twelve deaths. Other provisions The 1911 Act granted miners an eight-hour day. No boy aged under 14 could be employed below ground unless they had been working below ground before the Act was passed. Boys under 16 could not be employed above ground at night, although they could be employed underground. The Act brought in strict regulations to provide for the general welfare of pit ponies working in the mines, although the use of ponies would continue for many years. The Act provided that a manager or under-manager had to personally supervise each mine on a daily basis. It established the Mining Qualifications Board to ensure that colliery managers and under-managers, firemen, deputies and shot-firers who would be wholly or partly responsible for mining safety were suitably qualified, and to issue certificates of competence. Mine owners were required to secure disused or abandoned mine openings against accidental entry. The Act §97(1) specified that Welsh-speakers in Wales would be preferred as inspectors of mines in Wales, but the Mines Department did not take this rule seriously. Notes Sources United Kingdom Acts of Parliament 1911 December 1911 events Coal mining in the United Kingdom Coal mining law Winston Churchill H. H. Asquith