Visited August 2008 with The Riddlers and BenWRX
In 1939 two open quarries were bought by the Air Ministry for use as ammunition storage.
The depot consisted of two levels, with access to the lower level by either narrow guage railway or by truck to delivering the ammunition.
Bombs from the lower could be transfered to the next level via 3 lifts throughout the depot.
The top level was arched for extra strength and was covered by slate to hide the depot and to give extra protecting from any air attacks.
But in 1942, just 6 months after the depot opened the central area of the complex collapsed burying 14,000 tons of bombs.
The site was not used for bomb storage again although was used for bomb disposal and the old slate pits on the site had hundreds of tons of old ordanance dumped into them.
In 1956 when the site finally closed down bombs littered the entire site, some had not been properly destroyed and in 1969 a unit from the Royal Air Force were brought in to completely clear the site of any old bombs. A task which took them 6 years to complete.
The site itself is in a fairly remote location and has suffered only minor vandalism. Railway tracks from the narrow guage railway are still there, the tunnels are in condition with light fittings still in place.
Only one original painted sign was found and a small pencil markings that look as though the bombs were counted by hand as they were delivered to site.
See more pictures of Llanberis Ammunition Depot