The Glyn Neath Gunpowder Works (Glyn Neath Powder Mills) was situated on a site of about 73 hectares in the valley of the Afon Mellte, above Pontneddfechan. For reasons of safety it spread along the valley for about 2 kilometers, most of the various units being connected by an internal tramway. The works was established in 1857 by the Vale of Neath Powder Co. for the manufacture of blasting powder (black powder) for use in the South Wales coalmining industry. In 1862/3 it was taken over by Curtis's and Harvey and later merged into Nobel's Explosive Co. which became part of Imperial Chemical Industries in 1926. The works ceased production of black powder on 31 December 1931, following the decision of the Home Office to remove it from the `Permitted List of Explosives'. The works continued in use for the storage of explosives until final closure in 1940. Many of the structures were demolished for safety reasons, shortly after closure.

The function of individual structures is described under their entries, but a brief resume is given here:

The main ingredients for gunpowder: saltpetre (potassium nitrate), sulphur and charcoal were each ground down into a powder before being mixed together. The mixture was known as the `Green Charge'. This was then compacted into a homogenous mass in the Incorporating Mills and then highly compressed into slabs in the Cake Press Houses, following which it was broken into smaller pieces. The pieces were reduced to grains by crushing in the Corning Houses, and sieved into various sizes. The grain powder was dried in the Stove House and then sieved again to extract dust in the Dusting House. Some of the powder then went to the Glazing House where it was polished and made suitable for blasting powder; the remainder was compressed into pellets in the Pellet Press Houses. Both products were then packed and then sent for storage in the Magazines to await distribution.

RCAHMW, February 2011