Outside Kent

A disused slate quarry near Llanberis in North Wales proved to be an ideal site for use as an ammunition store, and at the outbreak of World War II the site was procured for the storage of bombs. The quarry was ideal as it already had deep pits in place. all linked by connecting tunnels.

The site was a medieval chalk mine, the ground here is a few feet of flood gravels covering about 50ft of the Thanet Sands which lie on the Upper Chalk with its distinctive black flints. In many places the roof breaks through into the beds above showing the original land surface when the chalk was exposed and eroded and then recovered.

Marden Mine is a mine dug into the Upper Greensand of North Surrey. This has had a long and varied history and undergone a variety of uses. In brief: it started in the mid 19thC as a firestone quarry virtually identical to and contemporary with Godstone Main Series (GMS) just ½ mile to the west.
 

This structure began as a tunnel system in a quarry. During the Second World war it served two purposes; one section housed national treasures of great value. It was rumoured that the Crown Jewels were kept here with the area totally secure and even boasting one of the earliest smoke detectors.