The X Site, Rhydymwyn.
There is something mysterious and attractive about tunnels and caves. Maybe each of us has a troglodyte inside us. The doors have to be secure, the guide said, otherwise people get in and it's not safe.
'What are they expecting to find?' I asked.
He shrugged. 'There's rumours... Stupid things like the crown jewels were kept here during the war. Maybe they're hoping something was left behind.'
The stores are empty now and no one goes in except for a couple of times a year when a builder comes to inspect the roof and make it safe. Over the years the concrete crumbles and metal rusts. Ground water trickles down and sometimes becomes a torrent. Here, where men attempted to control nature, they are now tentatively allowing it back; but only on their terms - the ground water is piped into a wetland rich in wild life, and the grass once mown is rolled into vast short cylinders to provide warm winter quarters for snakes.
After the mines came something else, and and it is this that drew me here: just before the second world war ICI (which used to the main chemical company in the UK) was encouraged, or commanded, I'm not sure which, to produce millions of shells of mustard gas. Since their works in Runcorn were too vulnerable they looked around for somewhere else suitable fairly close. This valley, with its infrastructure of mines and associated works, seemed ideal.
To the existing buildings they added more. Some of them still stand, others have subsided into grassy mounds, but altogether there were dozens of brick-built workrooms. Some of these made the mustard gas, while further along, in the section known as the danger area, the mustard gas was put into shells and primed with explosives. This was done in several small buildings, rather than one large one. This was common practice for explosive work, my guide said - if one exploded, the others could just carry on.
The shells were then distributed around the country ready for action. As production built up there were well over a thousand workers here.
Today there is no one except three men employed by DEFRA (a government agency) to generally manage the place, and a group of wildlife specialists who monitor the plants and animals. As we walked down the track a thin fox stepped out in front of us and a buzzard flew off silently from some trees. Six decades ago it would have been noisier and more crowded; brown-uniformed workers would have periodically spilt out, perhaps in response to bells and sirens, to go to the cleaning and toilet block, the changing room or canteen...
...or hurry for shelter. They would have worn tracks with their many feet. The grass would have been short. The asphalt, now rippling and breaking with age and the effects of too many hot summers, would have been new, gleaming, black. It was a special spark-free sort, and the hammering, scraping and sawing around us would have come from spark-less copper tools too.
Further along we looked for grass-snakes under pieces of tin-roof in the grass but just found scurrying ants heaving around their out-sized eggs. Beside us was the river Alyn, regimented by concrete, diverted from one course to a more convenient one, disappearing underground to emerge the other side of the compound, outside the fence - a home to kingfishers and otters.
Near to the river were the remains of a small railway station, and a platform and shelter for unloading. The guide thought it was just the charges (not people) that came this way, brought in from a small battery up on the hills.
Close by were two brick shelters that had been cleared out so we could go inside. When the Germans had invaded France they could bomb further to the west, and Liverpool, just north of here, was targeted. On their return flight they were liable to discard any unused bombs and so the workers here would have to take shelter too.
The small recess in the corner would have had a curtain hanging over it, and a chemical toilet inside. About fifteen people each side would sit in here on benches against the wall for hours during raids. For a few moments we stood in silence. Is this how they too would have waited - intensely listening for the planes to whine close and then whine away again? Maybe with each distant thud in the Liverpool docks they would have shifted slightly on their hard seat, and the faint smell of explosive charge, sweat and mustard would rise again from their clothes, and then the stronger, more pungent smell, of whatever was behind the curtains.
The paint on the walls would have been fresh then, today it just flakes away: egg-shell blue, greens, creams, whites, and then, picking out the outline of the housing of the slam doors, the remains of black and the black-out.
This was how the Rhydymwyn started the second world war, but by the end, the site would have made another deadly contribution: around 1942 they started a process to enrich uranium here. It was the British contribution to the start of the Manhattan Project. Even though this building pre-dates the project I think it looks sinister with its blank walls and concrete towers.
Trees grow here now and split the masonry apart. Alder and ash sprout as quickly as dandelions and soften edges with young fern-like branches. The job of the men here is changing from building maintenance to nature regulation as they are instructed to stand back and let it happen. Sand Martins swoop for insects. Recently a rare kind of red-veined dragon-fly has been spotted and its discovery recorded - the most northerly range of its species. If someone finds an adder here it will be designated a site of special scientific interest, and my guide doesn't relish the restrictions that would bring.
Meanwhile some of these particular walls would no doubt tell some of their secrets to a chemical detector or perhaps a geiger counter (ADDED LATER 27th August) although I have since been told there is no evidence that radioactive material was used at the site, but there is much that is in danger of being lost.
In the village a ninety-year old woman remembers working here, but is not able to tell anyone much, my guide says, except that she poured something from something else, according to instructions, and periodically important men would come; government officials and scientists in suits and glasses.
In the visitor centre there are photographs. Scientists in an assortment of ill-fitting white coats stand outside their buildings - which look only slightly less ramshackle than they do today. There is a single photograph of their laboratory - a selection of rubber tubing and cylinders on stands against white tiles.
It is tantalising and I would like to know more. The chemists, my guide said, lived in houses bought by ICI for them in the village. Around here, and over other areas of the country ICI had power and great wealth. When we first moved to the north-west it owned small hotels and financed interesting and charitable schemes. To my parents generation 'the works chemist' was a position of prestige. I imagine them as slightly aloof members of the community - like the village doctor and the vet.
Now, of course there are no chemists, and ICI is gone, bought out this year by a company that also owns Nobel. For some time both Hodmandod Senior and I were employees, but gradually the different components were sold and, very often shut down. The UK has turned its back on manufacturing as it embraces the information age so I have found that my own fascinating discipline, chemistry, is becoming somewhat redundant in its own right (although useful in other ways). Considering much of what chemists did, and what they represented, certainly in this valley, I do not regret some of their passing.
After the war these millions of shells of mustard gas were dumped. Some of it (not much I hope) was found here in this marked section of ground in the mid-distance.
A lot was dumped in the Irish sea and once, embarrassingly, was washed ashore. Eventually, and with the help of bleach, mustard gas degrades to something less harmful, a lot more quickly than uranium.
Bearing in mind all this, it is strange what the government decided to do next with this valley - and that was to store food. During the cold war vast quantities of fat, flour were kept here - together with small portable ovens for making bread. In the event of war the nearby town of Mold would have been fed with these supplies for a couple of weeks. Apparently there were similar depots throughout the country. The thought is chilling. Later the flour and the fats were replaced with crates of biscuits; one sweet, and good to eat, the other not - but edible with jam. They were hard, I guess like those Italian biscuits that take a long time to soften in the coffee, and were so packed full with 'essential nourishment' that a couple of would keep someone going for a whole day.
Nowadays, apparently, they would simply commandeer Tesco and people would be rationed with supplies from that.
(Update: The totem pole above is a piece of artwork commissioned by DEFRA which depicts the various interesting facets of the place: here you can see the wild-life, the mills, the works, and finally, on top, the Welsh dragon).
I found the whole place so fascinating that I have joined the local history group to find out more. I think it is important that the history of a place like Rhydymwyn is not lost, and I'm glad there are societies working together to prevent this happening. You can see more about the place, including old photographs and plans of the tunnel, here.
I first learnt about this place on the consistently excellent BLDG BLOG and find it strange that a blog written in Los Angeles should direct me to a place I'd never heard of on my own door step.