Senghenydd colliery disaster

The Senghenydd colliery disaster, also known as the Senghenydd explosion (Welsh: Tanchwa Senghennydd), occurred at the Universal Colliery in Senghenydd, near Caerphilly, Glamorgan, Wales, on 14 October 1913. The explosion, which killed 439 coal miners and a rescuer, is the worst mining accident in the United Kingdom. Universal Colliery, on the South Wales Coalfield, extracted steam coal, which was much in demand. Some of the region's coal seams contained high quantities of firedamp, a highly explosive gas consisting of methane and hydrogen.

In an earlier disaster in May 1901, three underground explosions at the colliery killed 81 miners. The inquest established that the colliery had high levels of airborne coal dust, which would have exacerbated the explosion and carried it further into the mine workings. The cause of the 1913 explosion is unknown, but the subsequent inquiry thought the most likely cause was a spark from underground signalling equipment that could have ignited any firedamp present. The miners in the east side of the workings were evacuated, but the men in the western section bore the brunt of the explosion, fire and afterdamp—a poisonous mixture of carbon dioxide, carbon monoxide and nitrogen left after an explosion.

Fires in the workings hampered rescue efforts, and it took several days before they were under control. It took several weeks for most of the bodies to be recovered. The subsequent enquiry pointed to errors made by the company and its management leading to charges of negligence against Edward Shaw, the colliery manager, and the owners. Shaw was fined £24 while the company was fined £10; newspapers calculated the cost of each miner lost was just 1 shilling 1+1⁄4d (about equivalent to £6 in 2023).

In 1981 a memorial to the men who died in the disaster was unveiled by the National Coal Board, followed by a second in 2006, to honour the dead of both the 1901 and 1913 explosions. In October 2013, on the centenary of the tragedy, a Welsh national memorial to those killed in all Wales's mining disasters was unveiled at the former pithead, depicting a rescue worker coming to the aid of one of the survivors of the explosion.

The Welsh coal industry employed 1,500 workers in 1800; as the industry expanded, the workforce rose to 30,000 by 1864, and to 250,000 by 1913. As employment became available, many people moved to the area of the South Wales Coalfield; between 1851 and 1911 the population increased by 320,000. By 1913 the Welsh collieries were extracting 56.8 million long tons (57.7 million tonnes; 63.6 million short tons) of coal a year, up from 8.5 million long tons (8.6 million tonnes; 9.5 million short tons) in 1854; collieries in the region mined a fifth of all coal produced in the UK, and employed a fifth of its miners in the mid-nineteenth century. In 1913 Britain was responsible for 25 per cent of world coal production and 55 per cent of all world coal exports.

The South Wales Coalfield produced the sought-after anthracite, bituminous and steam coals—the latter a grade between the two comprising a hard coal without the coking elements. Some of the region's coal seams contained high quantities of firedamp—a mixture of methane and hydrogen—and were therefore prone to explosions; firedamp rises into the higher points of workings, including cavities or, as at Senghenydd, when the seams were being mined in an upward gradient. An additional danger of firedamp is afterdamp, a poisonous mixture of gases left after an explosion, primarily constituted of carbon dioxide, carbon monoxide and nitrogen. The carbon monoxide combines with haemoglobin in the bloodstream to form carboxyhemoglobin, which prevents the blood cells carrying oxygen, and can therefore result in suffocation by lack of oxygen known as anoxia. If survivors from an explosion are not rescued quickly, they face the possibility of being killed by the gas. The presence of firedamp in South Wales's collieries contributed to a higher-than-average proportion of accidents: between 1880 and 1900 South Wales accounted for 18 per cent of Britain's miners, but 48 per cent of all UK mining deaths occurred in the region. As coal output from British collieries reached its peak in 1913 there was a correspondingly large number of accidents around this time.

Senghenydd (Welsh: Senghennydd) is situated at the northern end of the Aber Valley, approximately four miles (6.4 km) north-west of Caerphilly and eleven miles (18 km) north-west of Cardiff. When geological surveys for coal began in 1890 it was a farming hamlet of around 100 people. Coal was found, and sinking of the first mineshaft for Universal Colliery—which was owned and developed by William Lewis—began in 1891; the first coal was extracted in 1896. The colliery's two shafts were both 1,950 feet (590 m) deep, the downcast Lancaster and the upcast York. Development of the pit coincided with the Boer War, and sectors of the underground workings were named after key places in the war, such as Pretoria, or the lifting of the sieges at Ladysmith, Mafeking and Kimberley.

South Wales miners, including those at Universal, were paid on a rate determined by the Sliding Scale Committee, which fixed wages on the price coal fetched at market. When the price of coal slumped in the late 1890s, low wages led to industrial unrest and, in 1898, a strike that the men at Universal joined at the end of April. The Monmouthshire and South Wales Coal Owners' Association refused to replace the scale, and the strike ended on 1 September with some small concessions granted by the owners. The colliery resumed production and in 1899 was producing 3,000 long tons (3,000 tonnes; 3,400 short tons) of coal a week.