The Berwyn mountains are part of the range that begin in Llangollen and end at Cader Idris by Dolgellau. The western and Northern sides of this range drop steeply into the Dee Valley, but the Eastern side is broken into steep sided channels which form the routes for a number of streams and rivers that begin in the Berwyns. One of these rivers is the Afon Tanat which springs forth about 5 miles to the West of the small village of Llangynog, it then flows eastwards past the Llangynog for about 12 miles until it is forced by Llanymynech Hill to flow South until it merges with the Afon Vyrnwy.
Prior to the last ice age the River Tanat flowed along the narrow space between Llanymynech Hill and Sweeney Mountain.
Following the industries of other areas of North Wales, slate and stone have been quarried in many areas of the Berwyns, Mining in all its various forms has almost certainly continued since prehistoric times and there is a distinct possibility that the Romans also mined in the area although to date no remains have been found to prove this.
The first documented evidence of mining comes in the latter part of the 17th century and one mine in particular at Craig-y-Mwn was providing considerable amounts of lead although the main problem experienced by early miners was that of transporting their goods for further processing such as smelting which was carried on at Pool Quay by the River Severn.
For the same reason the slate mines at Llangynog found they could not compete with other areas which were by then being served by narrow gauge railways, the albeit late arrival of the railway to Llangynog unfortunately did not help as by then the slate industry was in general decline.
However the arrival of the Tanat Valley light railway gave new life to other mines in the area as the improved transport made it viable to quarry the granite chippings that abounded and which were being used as surface dressing for roads needed by increased popularity of the car.
At the opposite end of the Tanat valley there were a number of Limestone quarries which had been enjoying good transport links via the Ellesmere Canal and the associated tramway links for over 100 years.
Considering the mineral and ore potential that existed along the length of the Tanat Valley it seems odd that the examples followed in other areas, of providing upgraded transport via narrow gauge railways was not followed here.
Modern travellers along the road which still winds its way along much the same route as the original drovers tracks can still see the many and varied sites of the mines and other works along the whole valley, most noticeable are the spoil heaps at Llangynog whilst at the other end the limestone quarry remains have been mostly reclaimed or at least disguised by nature.
However those who enjoy exploring (especially on foot) will find plenty of evidence of the former workings hidden in the trees.