The depot at Fauld became the site of the largest explosion in the UK, when 3,670 tons of bombs stored underground exploded en masse. Two explosions occurred where bombs were stocked in bunkers covering 180,000 sq ft of concreted corridors. The passages were 12' high x 20' wide and had space for trucks. Inside the atmosphere was 'clear air' at 55 F.
After the explosion there was a mushroom cloud, about 50 yards wide and upwards out of sight. Mounds of earth weighing up to a ton in weight fell to the ground. Afterwards a fine dust up to 4 inches thick fell, and it was possible to walk without making any noise. A crater, half a mile across and 100 feet deep was left behind.
That RAF inquiry found that the most likely cause was an airman trying to remove an exploder pocket from a 4,000 pound bomb, with a brass chisel - causing a spark, which caused an explosion which set off others.
The inquiry rightly judged that "an airman was permitted to perform a dangerous operation in the mine. This indicates negligence on the part of the supervising staff present in the mine due either to lack of knowledge, lack of a proper sense of responsibility, or lack of proper direction from senior authority."
Yet no-one in authority was punished; indeed, the then commander of Fauld not only stayed in the same branch of the air force, but he ended up with the OBE.
In the area of explosion the earth moved! A 300-acre farm including people, animals, tractors, carts and buildings was completely blown away. The entire topsoil from a square mile of land went up and came back to earth up to 11 miles away. One man who survived had been cutting a field of roots on the edge of a wood; he reported that he watched as an entire 2.5 acres of woodland went up into the air and out of sight. Some trees returned to earth, being hurled so deep into the ground that farmers ploughing their land came upon them roots first. One man when he came to, did not know where he was because not a single landmark remained to remind him of where he grew up. In Burton chimneys toppled and buildings cracked.
The cause of the disaster was not made clear at the time. There had been staff shortages, a management position had remained empty for a year and 194 inexperienced Italian POWs worked in the mines. In 1974, it was officially announced that the cause of the explosion was probably a site worker removing a detonator from a live bomb using a brass chisel rather than a wooden batten. An eye witness testified that he had seen a worker using brass chisels in defiance of the strict regulations in force.
Two huge explosions were witnessed at RAF No. 21 M.U. Bomb Storage dump on 27 November 1944 at 11.15 hours. Eye witnesses reported seeing two distinct columns of black smoke in the form of a mushroom cloud ascending several thousand feet, and saw a blaze at the foot of the column. According to the Commanding Officer of M.U. 21 (Group Captain Storer) an open dump of incendiary bombs caught fire and it was allowed to burn itself out without damage or casualties. Property was damaged within a radius of 3/4 miles of the crater.
Debris and damage occurred to all property within a circle extending for 1,420 yards (1,300 m). Upper Castle Hayes farm completely disappeared and Messrs. Peter Fordes Lime and Gypsum works to the north of the village and Purse cottages were completely demolished. The lime works was destroyed by the destruction of the reservoir dam and the subsequent release of water into the works. Hanbury Fields farm, Hare Holes farm and also Croft farm with adjacent cottages were all extensively damaged. Debris also damaged Hanbury village. The crater was some 900 by 700 feet (210 m) in length and 380 feet (120 m) deep covering 12 acres. Approximately one third of the RAF dump exploded, an area of 65000 square yards, but barriers of rock pillars between No. 3 and No. 4 sections held and prevented the other munition storage areas from exploding in a chain reaction. Damage from earth shock extended as far as Burton-upon-Trent.