Lead smelting site on Bole Hill, west of Bolehill Lodge

Reasons for Designation

Approximately 10,000 lead industry sites are estimated to survive in England, spanning nearly three millennia of mining history from the later Bronze Age (c.1000 BC) until the present day, though before the Roman period it is likely to have been on a small scale. Two hundred and fifty one lead industry sites, representing approximately 2.5% of the estimated national archaeological resource for the industry, have been identified as being of national importance. This selection of nationally important monuments, compiled and assessed through a comprehensive survey of the lead industry, is designed to represent the industry's chronological depth, technological breadth and regional diversity. Medieval lead smelters include a range of features known from field or documentary evidence. The commonest type is the bole or bolehill, a wind-blown smelting fire located on an exposed hilltop or crest. This consisted of a rectangular or circular stone structure, open on one side, within which a large fire was constructed using large blocks of wood at the base and smaller wood interleaved with ore above. Boles used the wind to provide draught and were located on exposed summits or ridges, normally facing south west. The molten lead was run out by channels on the upwind side into a casting pit or area. The slags produced by the bole retained considerable quantities of lead. Some of this could be extracted by crushing and washing the slags and the remainder could be recovered by resmelting the slag in a smaller enclosed hearth (the slag hearth or 'blackwork oven') using charcoal fuel and an air blast normally supplied by hand or foot operated bellows; the resulting black glassy slag is distinct from the grey or yellow slag produced by the bole itself. The bole and associated features were in use from at least the 12th to the late 16th centuries. They are important as the main form of medieval lead smelting technology, differing markedly from the smelting technology of other metals. Boles are found on exposed sites in and around the Pennine lead mining fields; there is also historical evidence for their existence in Shropshire, but they are not known to have existed in the Mendip or south west England mining areas. It is likely that around 200 bole sites existed, with smaller numbers of slag washing sites (sometimes in separate locations from the bole). The majority of sites are known from place name evidence only; scatters of slag or visibly contaminated ground are unusual, and sites retaining informative slag distributions, intact tips, or visible structural or earthwork features are very rare. All sites with informative slag distributions, intact tips, or visible structural or earthwork features are therefore considered to merit protection. It is known that other types of lead smelter were used in the medieval period. There is documentary evidence for smelter types known as the 'furnace' in Devon and the Mendips, 'hutt' in Devon, and 'smelt mill' in North Yorkshire. On the Mendips, most smelting was undertaken at four central washing and smelting places known as 'mineries', probably using small open hearths blown by foot powered bellows. There is also field evidence for an enclosed smelting furnace (from the Isle of Man) and a range of sites identified by scatters of slag (from County Durham). These field site types cannot yet be fully correlated to the documented site types, and are a priority for future research. Due to their rarity, all non-bole medieval lead smelting sites retaining informative slag distributions, intact tips, or visible structural or earthwork features are considered to merit protection.

The site at Bole Hill, Totley is an unusually well preserved example of a medieval lead smelting site, containing visible evidence of at least one bole and two blackwork ovens, with associated casting channels and pits. The diversity of features is very rare in England. The site has enhanced amenity value due to its location on publicly accessible land within a National Park. The site is one of the best medieval lead smelting sites known to survive in England.

Details

The monument at Bole Hill, Totley is that of a medieval lead smelting site, including the bole itself and at least two slag hearths, with associated casting areas and slag tips. The bole lies on the crest of the ridge, orientated north-south and open to the west, and measures 7m x 3m externally. Traces of all three walls are visible. It is connected by casting channels to an oval casting area measuring c.2m x 1.5m. This may have been reused by a slag hearth immediately south of the bole. The main blackwork oven (a medieval slag hearth) lies c.50m north of the bole, also on the crest of the ridge, and consists of an oval area of contaminated ground (measuring c.5m x 3m) with traces of stonework, connected by channels to two small casting areas. A small pond c.7m west of the bole has been used for washing slags. The remainder of the hilltop is occupied by scatters of slag, charcoal, and contaminated ground. The lead smelting site at Bole Hill, Totley is likely to have operated from the medieval period until the later 16th century.

MAP EXTRACT The site of the monument is shown on the attached map extract.

Legacy

The contents of this record have been generated from a legacy data system.

Legacy System number:

24985

Legacy System:

RSM

Sources

Books and journals
Kiernan, D, The Derbyshire Lead Industry in the Sixteenth Century, (1989), 40-84
Kiernan, D, Van de Noort, R, Boles and Smeltmills in Bole Smelting in Derbyshire, (1992), 21
Kiernan, D, Van de Noort, R, Boles and Smeltmills in Bole Smelting in Derbyshire, (1992), 19-21

End of official list entry

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