HLW (C) 2

Hollywell Common and Halkyn Mountain  

2002  

Outstanding  

Designated  

The conjoining uplands of Halkyn Mountain and Holywell Common form an elongated plateau to the east of the Clwydian Hills, separated from them by the Wheeler valley, and overlooking the north east coastal strip of Flintshire and the estuary of the River Dee beyond. The area is about 250m above OD with small local summits protruding no more than 20m above this. The landscape so defined comprises the most important lead and zinc ore field in Wales, and is geologically part of the Carboniferous Limestone belt which runs south from Prestatyn in the north, to Hope Mountain and the northern side of the Bala fault in the south. Working is assumed to have started in Roman times because of the discovery of Roman remains associated with the production of lead, outside the area, at Pentre near Flint. Medieval mining is also attested from documentary sources, but 19th century mining has obliterated any traces of earlier workings. The area therefore bears valuable archaeological evidence of one of the oldest industries in Flintshire. The Quaker Company was instrumental in pioneering lead mining in the county from the late 17th to late 18th centuries, and there is documentary evidence of improvements in technology that allowed deeper shafts to be driven and the location of richer veins. The richest veins were worked intensely throughout the 18th and 19th centuries in the areas now referred to as Halkyn Mountain, Holywell Common and Pen-y-Ball Top, and in 1850, 11,500 tons of lead were produced amounting to about 12% of the British total. However, mining declined at the end of the 19th century in the face of cheaper imported lead, and there was only small-scale, intermittent activity following the First World War until the remaining mines closed in the 1960s. The ore field landscape is very distinctive, generally devoid of vegetation and now forms common land returned to rough pasture. Although most of the standing structures associated with the mining have now been lost, the landscape itself, comprising an extensive myriad of craters and tips of no great size, remains remarkably intact and is particularly apparent from the air. A recent survey in the area has recorded in excess of 250 mine sites. In the undeveloped areas, particularly Halkyn Mountain, the historical significance and value of the landscape is, therefore, in the workings themselves. The archaeological evidence consists mainly of shallow workings or deeper stonelined shafts, although several horse whim circles can also be identified. They bear evidence of the richness of the veins like Pant-y-gof, Pant-y-ffrith, Pant-y-pydew and Union Vein, where activity was centred on winning and removing the ores rather than dressing them on site. Of the larger mines, earthwork evidence remains of leats and reservoirs, some still holding water, which would have served the dressing floor areas. Where they have survived, small terraces of houses and mine offices have been converted to modern dwellings. Unrelated to the mining remains, but of industrial archaeological interest, Waen Brodlas in the south of Holywell Common is noted for structural remains and documentary evidence of a significant number of 19th century limekilns. Also unrelated to the mining remains, but included in the area, is the Iron Age hillfort of Moel y Gaer, Rhosesmor, sited on the summit of the isolated hill at south end of Halkyn Mountain. Extensive excavations on the site in 1972–74 before the construction of the covered reservoir, revealed evidence of the construction of the defences and of a remarkable succession of timber-built dwellings occupying the interior.