Mining and Smelting Experiments Publications Services Grants Received News & Updates Contact Us Comet Lode - Copa Hill

Created by


This website was made possible by a grant from the Cambrian Archaeology Association

Early Mines Research Group Who We Are Surveys Environmental Research Early Mines Research Group

In 2004 the EMRG excavated the site of Thomas Bonsall’s late 18th century water-powered (overshot 12 feet in diameter water wheel) stamp mill adjacent to the Nant-yr-onnen steam on Copa Hill, Cwmystwyth.

Here, harder quartz-veined lead ores were crushed. Water was used to lift a series of iron-shod stamps to crush the ore onto a grate as part of a wet stamping process. The lead concentrate was collected in a wooden tub beneath.

Cwmystwyth under snow - Stamp Mill excavation site, March 2004 (S. Timberlake)

Excavation of Thomas Bonsall's late 18th-century water-powered lead-stamping mill, Nant yr onnen, Cwmystwyth. (S. Timberlake)

Links Excavations
The excavation of an early lead-dressing mill of this type appears
to be unique (see : Timberlake 2007b)