The Box Mine

  • UK

    The Box Mine

Stretching between Box Hill and the end of Box Tunnel, its the largest stone mine in the country and possibly even the world. Stone had been quarried from Box Hill since medieval times using open pits but the extent of the stone was unknown until Isambard Kingdom Brunel came in to the town. Brunel built his tunnel through the hill which was completed in 1841. While his many men blasted their way through the hill they became aware of the vast quantities of good quality Bath Stone. Soon after building the tunnel several local companies started to mine the stone commercially, these companies were Pictors, Nobles and Stones. The mines evolved in a haphazard manner and pass over the top of Box Tunnel. Many of the mines ran in to each other underground causing the huge labyrinth of tunnels we have left behind today.The total quarried area is approximately 2 miles long and a mile wide in an oval shape. The total passage length of Box is estimated at 15 miles if not more. There were many air shafts leading up to the surface but most have now been filled in. The quarry has a system of light rail and a railway siding on the main GWR line at the Corsham end of the Box Tunnel.There used to be 10 entrances to the Box mines, and originally they were probably all separate quarries which eventually joined underground. These entrances were known as Eastgate, Westgate, Northgate, Bridgegate, Lady Hamilton’s Hole I, Lady Hamilton’s Hole II, Hazelbury, Clift, Backdoor and Jack’s Workings, named after a stone quarryman. All these entrances were adits, which means that they open in to the side of the hill or a cliff face.

Between the First and Second World Wars, however, a new role was found for the old workings. War clouds were gathering, and the rapid development of air power fuelled fears that the enemy bomber would always get through. The War Office decided that measures need to be taken to protect ammunition stocks from attack by hostile aircraft, and in 1935 the go-ahead was given for the construction of three ammunition sub-depots – one here at Tunnel Quarry, and the others at neighbouring Monkton Farleigh and Eastlays Ridge. Collectively, they were known as the Central Ammunition Depot (CAD). It had been estimated that CAD would take four years to complete but the first section – or ‘district’ – was ready by April 1938. Initially, the ammunition was lowered down a converted air-shaft by means of a steam winch but later, when all the ‘districts’ were completed, ammunition arriving by road or rail was unloaded at Surface Loading Platforms (SLP), one located at each sub-depot.

Tunnel Quarry sub-depot had a standard gauge underground railway, complete with two platforms and locomotive shed, while the other sub-depots employed conveyor belts to connect with nearby railway sidings. Movement underground was by an ‘endless rope’ truck haulage system, similar to that used in coal mines. However, excessive noise and the danger posed by derailments led in 1940 to the system’s replacement by approximately 7.5 miles of conveyor belt at Tunnel Quarry and Eastlays Ridge. When completed, Tunnel Quarry sub-depot consisted of ten ‘districts’, each with approximately five acres of floor space. Giant fans drew in fresh air and expelled the stale, producing a stable atmosphere of 65oF and 80% humidity.

In 1941 a barrack block was constructed underground at Tunnel Quarry. It could accommodate 300 personnel and was described by the RAOC Gazette as ‘magnificent’, with its bars and messing areas. There was a power station with two huge diesel generators capable of supplying power to a small town, and an underground lake for drinking water. Sewerage facilities and flood pumps were also provided. There was little need to go above ground, and during the Second World War many personnel remained underground for long periods to help keep the installation a secret. In February 1942 it was decided to establish a new military communications centre for the South-west of England, and space was found in Tunnel Quarry in No1 ‘district’, which never had been fully commissioned for ammunition storage. Work was completed by July 1943, at a cost of $50,000. Additionally, part of the Tunnels was set aside as a subterranean factory for the Bristol Aircraft Corporation, hidden away from the prying eyes and destructive capabilities of the Luftwaffe. It was this section of the Tunnels that, in 1943, was graced with the attractive murals painted by Olga Lehmann to brighten up the otherwise drab and gloomy working conditions. After the War, Tunnel Quarry retained its CAD role until the early 1960s, when the Royal Army Ordnance Corps vacated the site and took the last remaining ammunition with them. The Royal Engineers, who had maintained the site, abandoned their underground workshop a few years later, in 1966.

In the centre of the complex is an area known as the Cathedral, so called because of it's sheer size. It is a spectacular area of the quarry, measuring 190 feet long, 100 feet high and 25 feet wide at it's centre. In the roof of this chamber there is a large hole about six feet across. All the stone removed from this chamber was hauled through this hole to the surface between the years 1830 to 1850. Stone was quarried through on three levels creating a huge bell shaped cavern underground. The roof above the Cathedral is only fifteen feet thick and a row of cottages are partially sited on this.

From the  Box Quarry you can walk through in to the old MOD areas bordering Tunnel Quarry, this area of Box Quarry was used as an air in take to server the central ammunitions depot using the CDI (Corsham Depot Inlet) fan to draw air through the quarry in to the depots air conditioning system

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