Gunpowder Works

The steep sided, wooded valley of the Afon Mellte, famous for its beautiful waterfalls, contains the ghost of what was once a thriving industry.

Gunpowder works are an incredibly rare type of heritage site. There was only ever one other gunpowder factory in the whole of Wales.

The Glyn-Neath Gunpowder Works, or Powder Mills, were established near Pontneddfechan in 1857 to produce blasting powder (known as black powder) for use in coal mining and limestone quarrying. The works operated until 1931.

This steep sided valley might seem a strange place to build and operate a manufacturing business. However, the location was actually well suited to the dangerous process of manufacturing gunpowder. The site was large and remote, stretching over a mile and a half along the north bank of the River Mellte, with room to create plenty of space between each factory building to ensure that any explosions were localised.

There was also free energy on tap – the River Mellte powered the factory's waterwheels and turbines – and raw materials (charcoal, sulphur and salt petre or potassium nitrate) could all be sourced in the vicinity. The topography of the valley was very useful, too. The factory was built into the steep slopes with large banks between buildings, to stabilise them and reduce the impact of explosions. And despite its remote location, Pontneddfechan was well connected to transport links including the Neath and Swansea Canal and the Vale of Neath Railway.

Raw materials came in at the bottom of the site and were transported around by tramroad until the finished black powder came out at the top. The quality of the black powder was tested by using it to fire a cannon which is now in Brecon Museum. Only if the powder propelled a cannon ball a specific distance did it make the grade.

Safety was paramount and all possible precautions to avoid explosions were taken. Employees had to change into work clothes before entering potentially dangerous areas. They wore leather slippers fastened with wooden pegs over their shoes and boots. Trousers were not allowed pockets or turn-ups to prevent grit to be carried into the works in case it caused sparks.

Large areas of the works were regularly dowsed with water to keep them damp in a process called liquoring. If an explosion occurred in one building other areas of the works would automatically be drenched to prevent the explosion spreading. Despite these precautions many explosions were recorded.

What there is to see at the Glyn-Neath Gunpowder Works

After many years of successful operation, the factory ceased production when black powder was prohibited from use in coal mines, and demand fell. The site was completely abandoned by 1940, and many of the buildings were burnt out and demolished because of the risk of accidental explosion they posed. However, enough of the buildings survive to hint at the scale of the factory.

You can walk along a flat and level path, the remains of one of the tramroads that moved materials around. It leads past the remains of factory buildings, some of which are hard to spot as they're very overgrown and hidden in the trees. Other remains are more obvious, such as the large concrete Corning House where cakes of granulated powder were broken up by wooden hammers.

Stone and masonry structures housed the machinery. You will notice that many of these have three walls. This is because the roof and the fourth wall would have been made of wood to allow any explosion to move up and out of the building and limit any damage to the expensive machinery.

There are also extensive remains relating to the water management system, including leats, aqueducts, weirs and hydraulic pipes.

As you stroll through the site, imagine what it would have been like for the people who worked here. In its heyday the Gunpowder Works employed 65-70 people, mostly men. It was a dangerous and dirty job with long work days, from 7am to 5pm. Despite this, the workers did not earn any more those in any other local industries. However, the company did provide accommodation for staff and a schoolhouse in the village to educate employees’ children. They also allowed employees to build and maintain gardens on the spacious gunpowder works site.

Visiting the Glyn-Neath Gunpowder Works

The site is owned and managed by the Brecon Beacons National Park Authority. Access is free.

How to get there

Pontneddfechan is located off the B4242 at the northern end of the Vale of Neath.

Nearest town or village

Pontneddfechan, Glyn-Neath

OS grid reference

Explorer Map OL 12 or Landranger Map 160 – SN911080


Pontneddfechan has several pubs, a post office/shop and the Waterfalls Centre, a local information centre


At Pontneddfechan Community Hall or at the nearby Dinas Rock car park


Near the Waterfalls Centre, Pontneddfechan. Disabled access toilets in Cwm Porth car park near Ystradfellte.

The Powder Trail

This audio trail, produced by Forestry Commission Wales, reveals what life was like working at the Gunpowder Works . Click here to download it as an mp3 file.