Former Valley Works (MoS Factory)

 cave / caves, closed / former military, chemical warfare, nuclear research centre

This once top secret site known as the Valley Works produced huge quantities of mustard gas and pyrotechnic munitions. The site has three tunnels running into the hill-side into huge underground storage facilities. Later in the war it was involved in developing uranium separation for the atomic bomb. Code name Tube Alloys.

The MS Factory (Ministry of Supply), Valley was a Second World War site in the United Kingdom that was used for the storage and production of mustard gas. It was later also used in the development of the UK's atomic bomb project. More recently, it became a bulk storage depot for emergency supplies. In 1939 the land was purchased by the Ministry of Supply and developed as a purpose built chemical weapons factory and storage facility.

Over 100 specialised buildings were constructed across the site, linked by an extensive rail network established around a spur off the Chester to Denbigh mainline. Other major landscaping undertaken at this time included the canalisation and culverting of the River Alyn, and the excavation of a complex of interlinked subterranean, rock-cut tunnels and caverns. During World War II the plant produced ordnance containing mustard gas, and was associated with the development of the Atom Bomb.

In the immediate Post-War period the site was used to store German nerve gas, and it was not until the 1950s when Britain relinquished its chemical weapons (CW) capability that the site as a chemical storage facility was defunct. However, the site remains on the international Chemical Weapons List, and is still monitored as such.

On accepting the findings of the Maud Report in 1941, the government of the day needed to verify that a cost effective atomic bomb could be manufactured. This required verification that a gaseous diffusion process would work on an industrial scale to provide enough fissile material to manufacture a cost effective and timely Atomic Bomb.

One of the surplus Pyro buildings at Valley (P6) was adapted for the testing of apparatus for uranium isotope separation in 1942 in an early phase of the ‘Tube Alloys’ project before this was moved to America (developing later into the Manhattan Project).

ryhdymwynvalleyhistory.co.uk/