This year, 2013, is the centenary of the Senghenydd Mining Disaster, a tragedy that claimed the lives of 436 men. It was the largest - I hesitate to say "greatest" - mining disaster to ever occur in this country. But mining was always a hazardous occupation and the history of Wales is littered with events of almost similar magnitude.
The Gresford Disaster of 22 September 1934 was one such case. The Gresford Colliery sat just north of Wrexham, the original shaft being sunk in 1908. By 1911 the pit, owned and run by the Westminster and United Collieries Group, was ready to be opened.
There were two shafts: the Dennis, named after the mine owners, who were the principal landowners in the area; and the Martin. The Dennis shaft reached a depth of approximately 2,264 feet, while the Martin was just a few feet shorter. Together, they were the deepest mining shafts in the whole of Denbighshire.
It was unfortunate that the Dennis shaft was very prone to fire damp. Working conditions in the Dennis were always poor, the air being constantly hot and humid. Ventilation was also bad and while there had been a degree of mechanisation, because of the conditions underground some of the coal was still mined by hand.
By September 1934 the Gresford Colliery was employing around 2,200 miners. The previous year the colliery had made a loss and manager William Bonsall was under considerable pressure from the Dennis family to ensure that it did not happen again. That September the colliery was working around the clock in an effort to increase profits and on 22 September 500 men were working the night shift.
At 2.08am a huge explosion rocked the mine. The explosion occurred about 1.3 miles from the bottom of the Dennis shaft and fires immediately broke out. The fires not only killed 266 men, they also blocked access and trapped miners behind the flames.
Six men managed to escape, all of them enjoying a mid-shift break when the explosion took place. Soon volunteer rescue teams, from Gresford itself and from Llay Main Colliery, arrived but they, too, encountered disaster.
Three members of the Llay team were overcome by gas; John Charles Williams, the team leader, was the only survivor. It was later rumoured that Williams was the author of the anonymous ballad The Gresford Disaster, a poem that was openly critical of the managers and management of the mine.
All weekend the rescue teams battled with the flames and the rubble. But on the Sunday evening they were eventually withdrawn as conditions were felt to be too hazardous. The shafts were capped and the fires allowed to burn out. Only 11 bodies were ever recovered from the mine; the rest were sealed up underground.
There were more explosions over the following week but with the mine sealed and nobody working underground they did not cause undue problems. However, a few days later, mine worker George Brown became the final victim of the Gresford Disaster when he was hit by flying debris after a blast blew off the cap on the Dennis shaft.
The disaster brought untold hardship to the area. The wages of over 1,000 miners were docked by the owners as the men had failed to complete their shift - short sighted and incredibly cruel management. And, of course, the mine stayed closed.
By the end of that autumn it was estimated that 1,100 Gresford men had been forced to sign on the unemployment register. Relief funds were set up, with over half a million pounds raised, but they could not even begin to compensate for the loss of regular income.
The inquiry that began on 25 October 1934 highlighted a lack of safety measures and bad working practices in the colliery. Te owners faced possible criminal charges over negligence, and they brought in a formidable team of barristers to fight their corner. They refused permission for anyone to enter the closed-off pit, something that was widely seen as a deliberate cover up.
The owners were never prosecuted and no single cause for the disaster was ever found, although Sir Stafford Cripps, the miners' legal representative, did later use evidence given to the Inquiry as one of the arguments for the nationalisation of coal mines in 1947.
As part of the nationalisation agreement, however, all records of the disaster and the colliery itself were destroyed - yet another betrayal by those in power.
Gresford Colliery reopened in January 1936, with miners working from a totally different angle and direction. The pit continued to run until it was finally closed, as uneconomical, in November 1973.
The Gresford Disaster remains the second largest mining disaster ever to occur in Wales. It decimated the Gresford area and is still seen as the result of cynical exploitation of working men by mine owners. It has to be remembered.