Silica Rock
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 gritstone is simply a sandstone formed from coarse angular grains of quartz.
It is the purity of these rocks are 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 a 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.
Dinas Rock Silica Mines
The mines behind Dinas Rock were a rather larger affair than their cousins alongside the Nedd Fechan. Several large entrances are still clearly visible from the path which drops steeply down from the top of Dinas Rock to the Sychryd.
Note that although they are situated on what is now Forestry Commission access land, none of the mine entrances should be approached due to the danger of rockfall.
The underground galleries were very extensive, extending over an area some 1000m x 500m. Parts of the mine are now flooded, others will have become unstable.
The material was transported by a series of tramways and inclines and indeed overhead cables suspended on pylons, down to the valley floor and then onward to the Pont Walby brickworks. The former tramway along the southern side of the Afon Mellte is a modern-day bridleway which allows the route to be traced on foot or pushbike.
In later days the material was taken to a brickworks at Swansea until the whole operation closed down in the 1960s.
the explore .
this is more of a underground walk more than anything it’s 95% flat walking and a brilliant place to relax and have a good mooch around , after a very physical morning caving it was a lovely place to stretch of and be able to stand up was amazing ! Here are some of the photos
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 gritstone is simply a sandstone formed from coarse angular grains of quartz.
It is the purity of these rocks are 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 a 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.
Dinas Rock Silica Mines
The mines behind Dinas Rock were a rather larger affair than their cousins alongside the Nedd Fechan. Several large entrances are still clearly visible from the path which drops steeply down from the top of Dinas Rock to the Sychryd.
Note that although they are situated on what is now Forestry Commission access land, none of the mine entrances should be approached due to the danger of rockfall.
The underground galleries were very extensive, extending over an area some 1000m x 500m. Parts of the mine are now flooded, others will have become unstable.
The material was transported by a series of tramways and inclines and indeed overhead cables suspended on pylons, down to the valley floor and then onward to the Pont Walby brickworks. The former tramway along the southern side of the Afon Mellte is a modern-day bridleway which allows the route to be traced on foot or pushbike.
In later days the material was taken to a brickworks at Swansea until the whole operation closed down in the 1960s.
the explore .
this is more of a underground walk more than anything it’s 95% flat walking and a brilliant place to relax and have a good mooch around , after a very physical morning caving it was a lovely place to stretch of and be able to stand up was amazing ! Here are some of the photos
The pillar repair in the photo I wonder if the miners removed it then the boss went mad and made them replace it or did it explode / fall out !!
