Lifting the lid on a secret site

By Nick Bourne BBC north east Wales

August 27 2009 marks 70th anniversary since the Treasury approved a £546,000 development of a World War II weapons plant - in 2009 it's a nature reserve

For years the secrecy surrounding the Rhydymwyn Valley Site, near Mold, served only to fuel rumour about what, if anything, could still be hidden in underground tunnels that once housed thousands of mustard gas shells during the height of production in the war years.

War-time film footage

In Pictures: Inside Valley Works

And speculation has been rife for the last few decades since it was revealed that the works played a role in the research into the first atomic bomb.

[That work included evaluating the atomic bomb research, codenamed Operation Tube Alloys. Many of the scientists who worked on Operation Tube Alloys worked on the Manhattan Project, which developed the first atomic bomb.]

But specialists from Birmingham University, who surveyed the site, released their findings in May 2006 - saying there were no more secrets lying hidden in the underground tunnels as they were empty.

What the experts did uncover, however, were some interesting archaeological finds after being commissioned by site owners - Department for Environment, Food and Rural Affairs (Defra) - to help provide a greater understanding of the site's history and how it came to be used during World War II.

The academics found that the site had been used from the mid 1700s for a range of industries which left behind remains of foundries, waterwheels as well as mine workings. In turn, this led to the building of a main road and a railway in the 1800s which made it a prime site by the time war-time Prime Minister Winston Churchill called on chemicals manufacturer ICI to find a secret location to begin production of chemical weapons.

ICI suggested Rhydymwyn, said the experts, because it was 30 miles away from its production hub in Runcorn, Cheshire; the amenities, including a natural water source and transport infrastructure were in place; and because it was inland and relatively safe from air attack because the site was in a valley, heavily wooded and, from the air, looked no different from other nearby valleys.

What happened on-site?

Production rooms were constructed to make mustard gas but, said the experts, this didn't happen. Instead, mustard gas shells were made on-site with all the components brought together to make the shells and bombs.

And what about the part the plant played in the creation of the first atomic bomb?

Well, apparently, leading experts were sent to the site by Churchill to follow up on a scientific research paper that showed how, in theory, a massive explosion - a chain reaction of explosions fractions of a second apart - could be triggered by splitting and using components of a certain chemical. Those same experts went on to play key roles in the US in the Manhattan Project, which developed the first atomic bomb.

Today, the site is considered historically important and in summer 2008 some of the uninspiring brick buildings were given protected status by Welsh heritage society, CADW.

It is also a nature reserve - but you have to book a visit in advance. More than 60 species of bird have been identified, including kingfishers, 150 species of flowers, including the bee orchid, and signs of an otter on-site led to an articifical holt being created.

For more information and to book a visit, use the reserve's own website or the website of the reserve managers, North East Wales Wildlife.

www.rvsweb.org.uk

www.newwildlife.org.uk