Gwaith Powdwr - family fun day 19th May 2012

Seventeen million grenades and other munitions were made at Cooke’s Explosives Ltd during WWII. Nowadays it’s an extensive nature reserve where the most lethal thing is an adder.

The site has a long history of explosives production starting from 1865 with gun cotton, then TNT and a range of ‘safety explosives’ for the mining industry. With the demise of British coal mining, the business was no longer economically viable and closed in 1995. Three years and six million pounds of decommissioning later, the site (Gwaith Powdwr) was donated by ICI to the North Wales Wildlife Trust.

On Saturday 19^th May there will be a ‘fun day for all the family’ from 10:30am to 4pm including bushcraft, pond dipping, minibeast hunting and so on. This is a free event although donations are most welcome. To whet your appetite here is a recent film clip:

It’s a brilliant place to explore, bringing together a mix of natural history and industrial history. It used to be the biggest employer in the area with a workforce of five hundred in the 1960s but today’s only employee is Rob, the warden, helped by a small army of volunteers.

A massive explosion occurred in 1915 (enemy sabotage?), totally destroying the facilities, and responsibility for the site was taken over by the Ministry of Munitions before being sold to Cooke’s in the 1920s.

A key feature of the 60-acre site is the partitioning into three valleys – in the wake of the big accident, production was distributed across the valleys to limit the risk of an explosion in one area spreading to the other.

One of these was called Klondyke Valley because the pipework required for producing nitro-glycerine resembled a gold-rush town. The plumbing has gone but one of the key buildings remains, the Settling Shed. Amongst other things this housed seven settling tanks in which residues of nitro-glycerine were removed from the water used to keep the explosives cool and stable.

When explosives are being mixed it is essential to keep them cool and the process involved piping in water from a nearby pond with an operator monitoring temperature dials and adjusting the flow of water accordingly. Probably not the most fulfilling work but exceedingly important. For his comfort he was provided with a stool but for his protection it had just one leg – if he fell asleep, it would not be for long! 

This is the most modern of the buildings dating back to 1988 when a huge blast destroyed the previous one, killing two of the employees, and shaking the buildings of Penrhyndeudraeth like an earthquake.

Ballistic pendulum

The footpath across the summit of the hill goes through the heather to the Pendulum Shed. Not some giant clock although people in the town could set their watches by it at 2 p.m. every weekday. Suspended from a steel frame is a two tonne ballistic pendulum (pendil balistig) with a pair of rails in front. A canon mounted on the rails was fired point blank at the pendulum. The force of the explosion would cause the canon to recoil on its tracks and the pendulum to swing – the degree to which it swung was the measure of how powerful the explosives were!

This part of the site is the area where nightjars breed and during early summer the footpath is closed to prevent disturbance. Guided walks are organised by Rob – it’s unusual to see these pre-historic looking birds, but the noise is unmissable, it sounds like the rumblings of a diesel engine.

Sandbag wall - great for nesting

Dotted around the site are several Explosives Sheds where products were wrapped and sealed in wax to protect them from the damp. The sheds have detachable roofs and are surrounded by thick safety walls made of sandbags so that in the event of an explosion, the force of the blast would go upwards and not sideways … adds a whole new dimension to ‘raising the roof’. Sparks were a hazard to avoid and to that end the floor was lined with lead and workers provided with rubber shoes and anti-static overalls.

Linking all these buildings and remote areas of the site is a network of tarmac and railway tracks. My first impression of the fading tarmac was that it was out of place in a reserve but on the other hand they make easy access for pushchairs, wheelchairs and mobility scooters. One of the railway tracks went through a tunnel which is now grilled off and makes a great hibernation roost for lesser horseshoe bats. Bats have also colonised the emergency shelters where workers would take refuge in the event of the alarm being sounded.

The final building in the explosives process is the Belfast Store where explosives were safely stored prior to shipment by rail or by ship. One of the many safety features of this building is the lightning conductor, an unlucky strike could set the whole thing off. Cooke’s had their own steamship called the Florence Cooke which started work in 1923 and during the war was used as an ammunition ship at Scapa Flow and took part in the Normandy landings.

Alas in 1959, the year after Mr Cooke retired and ICI took over, it was decided that road transport was more efficient and she was sold for scrap.