Banc Tynddol Roman and Early Medieval Lead smelting [SN 809 748]

When John Leland, the King’s Antiquary under Henry VIII, passed through the Ystwyth Valley sometime between 1536 and 1539 as part of his survey of the monastic lands of the nearby Strata Florida Abbey, he referred to the mining on this hill and Graig Fawr (to the west) as well as to the evidence for former lead smelting within the general vicinity. The geologist O.T.Jones in 1921 noted the traces of smelting debris at Penguelan in the valley bottom, and this site was then re-discovered in 1990 following survey work carried out by the EMRG.

Excavations carried out in 1999 and again in 2002 and 2003 revealed the destroyed and strewn remnants of at least three Early Medieval wind-powered bole furnaces dating to two distinct periods: 880 -1020 yrs cal AD and 1030-1300 yrs cal AD. The latter phase at least might relate to the working of the mine by the lay brothers or tenants of the Cistercian monks of Strata Florida. These hearths appear to have been built as simple stone structures above ground and the smelting process seemed quite inefficient.

A geophysical magnetic susceptibility survey carried out in 2002 suggested the existence of another type of furnace (PSS4) which on excavation proved to be a clay and stone-lined pit bole hearth of Roman origin.

This hearth which appears to have been used on several different occasions was worked in a quite different way. This produced a lead-poor glassy slag and a pool of metal which on occasion had overflowed and solidified into a channel of lead, the course of which could be traced some 8m down slope. A radiocarbon date obtained from charcoal closely associated with this lead suggested that the smelting furnace was in use during the Roman period sometime in the 1st-2nd century AD. (Timberlake 2002).   

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Plans and sections of the Roman hearth.

Sites of Medieval and Roman hearths and lead channel associated with the Roman pit bole.