Report - - Lower Dinas Silica Mine, Powys - March '12 | Mines and Quarries | 28DaysLater.co.uk

Report - Lower Dinas Silica Mine, Powys - March '12


The Rock Man
28DL Full Member
This is the lesser known "lower" silica mine at dinas, probably because that the entrance is very easy to miss, in fact we walked passed it and didnt realise!

Visited with cunningcorgi and ratty.

The history bit

The area around Pontneddfechan at the head of the Vale of Neath is one of very few in the world where sandstone has been extensively worked in underground mines. But then this is a very special sort of sandstone.

In the steep walls of the gorges of the Nedd Fechan, the Afon Mellte and the Sychryd are exposed beds of a very hard and pure sandstone which have come to be known as 'the Silica rock'. It is in fact the lowermost of a whole family of such beds which collectively are termed the 'Millstone Grit' - a gritstone is simply a sandstone formed from coarse angular grains of quartz or 'silica'. It is the purity of these rocks - almost 100% silica (SiO2) - that made them a target for miners from the 18th to the 20th century. The burgeoning industries of industrial South Wales needed large numbers of heat-resistant bricks to line the furnaces in which copper and iron-smelting took place. Only bricks made from more or less pure silica could stand the intense temperatures without shattering.

The silica rock was worked through a series of adits - horizontal mine passages driven into the side of the hill - both behind Craig-y-ddinas and on either side of the Nedd Fechan upstream of Pontneddfechan. In both cases tramways were forced through difficult terrain to these mine entrances to permit horse-drawn drams to take away the rock to the brick works. An early factory was built by Messrs Frederick and Jenner at Dinas Bridge and a works was later established at Pont Walby near Glyn-neath.

1 Tramway


2 Passageway


3 Left or right?


4 Formations


5 Dead end


6 Pillar


7 Exploring


8 Last shot by the entrance