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 2025).
In 1981 a memorial to the men who died in the disaster was unveiled by the National Coal Board. 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.
Background
Welsh coal industry
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 and the Universal Colliery
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.
The industrial historians Helen and Baron Duckham consider Universal Colliery to have been "an unlucky mine". At approximately 5:00 am on 24 May 1901 three underground explosions occurred as the night shift was exiting the pit. Because the explosion damaged the pit winding gear, it took time to clear the debris from the pithead to allow rescuers to begin work. They descended at 11:00 am and rescued one man, an ostler, found alongside the corpse of the horse he was tending. There were no other survivors and 81 men died. The funerals for the victims started four days later, and the rescue and recovery operations lasted for six weeks.
The Mines Inspectorate began an enquiry, chaired by the mining engineer William Galloway. The report was published on 15 July. It stated that the mine was hot with high levels of coal dust present. The method used to load coal onto underground trucks created quantities of dust, which had aggravated a small explosion and created a chain reaction of related explosions throughout the workings. An inquest held in October concluded that various safety precautions had not been followed, and had the mine been sufficiently watered it would have reduced the coal dust held in the air. The colliery had further problems in October 1910 when a heavy roof fall in the Mafeking return released trapped firedamp, which caused the mine to be temporarily evacuated.
In 1906 a major explosion at a colliery in Courrières, northern France, caused the deaths of more than 1,000 miners. The subsequent report blamed the accidental ignition of firedamp, exacerbated by coal dust in the air. Concerned that a similar disaster might happen in 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 (1,800 tonnes; 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 overman D R Thomas. The descent was slow, and they had to clear several girders and obstructions before they reached the bottom. They found that the men from the east side of the workings (approximately 450 workers) were unharmed, and their evacuation was ordered. Shaw and Thomas moved to the western side, where they found other men, alive but injured, and arranged for them to travel to the surface. Thomas later reported that the view into the western workings "was exactly like looking into a furnace".
Shaw explored what he could of the western workings, before he and some of the survivors began tackling the fire. The water pipes from the surface in the Lancaster shaft were all fractured, and hand-extinguishers were used. Shaw returned to the surface at 9:30 am to arrange for rescue and fire-fighting teams from neighbouring collieries. From 11:00 am the specialist mines rescue teams began arriving at the colliery from the Rhymney and Rhondda Valleys, as did Red Cross workers and local ambulance services; a police detachment was sent from Cardiff in a special train. Members of the Inspectorate of Mines were quickly on the scene, and an inspector descended to view the mine the same morning.
Lieven recounts how the rescue parties "in their desperation, ... were reckless with their lives" in their attempts to find survivors; many were injured in small roof collapses, or suffered the effects of carbon monoxide poisoning. Their endeavours saved lives throughout the remainder of the day and into the night, including a group of 18 men found at around 1:00 am. They were the last survivors found. A total of 432 miners had died that day—some bodies were not found until later—and 7 others died later in hospital or at home. A journalist from The Times wrote: "The numbers are truly awful. We talk in awed terms of the decimation of a regiment in a bloody battle, but here a great community engaged in the pursuit of a peaceful vocation is threatened with the loss of at least a quarter of its able bodied manhood". On the surface the townsfolk waited for news; a reporter for The Dundee Courier thought: "the scene at Senghenydd last night was depressing in the extreme. The streets were full of silent throngs of people who moved aimlessly about or stood stolidly at the street corners."
Rescue, fire-fighting and recovery: 15 October to 30 November
Work continued throughout the night of 15 October and into the following day. It focused on finding survivors and fighting the fire that blocked the entry into some workings of the western returns. The fire caused the roof supports to become unstable, and falls triggered outbursts of methane. Several rescuers were injured by the falls, one fatally. Before descending the mine many of the firefighters wrote what they thought might be their last letters home, and some made their wills. As the water pipe in the shaft was out of operation, fire-fighting continued with hand extinguishers and work was only possible in 20-minute shifts. Despite wearing respirators, several rescuers were overcome by the effects of firedamp. During the course of the day, 56 bodies were raised to the surface and, that evening, a new water supply, connected by three-quarters of a mile (1.2 km) of pipes to a nearby reservoir, was installed in the Lancaster shaft.
Reginald McKenna, the Home Secretary, visited the colliery on 15 October representing King George V, who was attending the marriage of Prince Arthur of Connaught and Princess Alexandra, 2nd Duchess of Fife. The king sent a £500 donation to a disaster relief fund; the royal couple displayed their wedding presents at St James's Palace and charged a shilling for entrance, raising £1,200 for the fund. The fund was started by the Lord Mayor of Cardiff; another collection, the Mansion House Fund set up by the Lord Mayor of London, raised more than £3,000 on its first day.