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Removing lead from ore is known as lead smelting. In the Peak District, this often did not take place at the mines which produced the ore, but in nearby valleys or more commonly further to the east. Much smelting of lead has taken place in the heavily-wooded Derwent Valley and on the East Moors and Coal Measure foothills of the Peak District. The traditional markets for lead have always been predominantly in the east, using the river ports on the Trent, Idle and Don, to take it to the Humber and on to Hull for distribution further afield. Thus, the lead smelting often took place on the eastern side of the orefield. The nearby availability of fuel for smelting was also an important consideration as often it was as expensive to transport fuel as it was the ore.
Up until the late-16th century the main medieval method of smelting was in bole hearths, which required high locations, such as the East Moors scarps and ridgetops that took advantage of the wind to create suitable draught for reaching the required smelting temperature. In post-medieval times, from the 16th to 18th centuries, a new smelting method was employed that used an ‘ore hearth’. These harnessed water power to drive bellows, and smelt sites migrated to valleys. However, from the 1730s onwards a further development, the cupola, was employed. These used coal to fuel furnaces, and some cupolas were again built on higher land, often to be close to coal sources. In other cases, valley sites were used despite the high levels of airborne pollution these smelters created. - - - - - - - - - - - - - - - - - - - Bole HearthsIdentified bole hearths on the East Moors concentrate on prominent scarp crests and ridgetops, sited close to hollow-ways that both facilitated transport of ore from the west and movement of smelted lead eastwards. By the early 16th century some boles were in regular use by professional smelters. Even these boles were often little more than large bonfires in which the ore was heated, therefore traces of their existence are often hard to identify on the ground today. However, sometimes the presence of boles is indicated by place names. Not all boles were on hilltops, an exception has recently been excavated in the narrow deep valley of Lynch Clough in the Upper Derwent area, on land used by Welbeck Abbey.
Medieval boles produced slags that could be re-smelted to produce further lead. These re-smelters, which were usually sited nearby, are known as blackwork ovens and were fired using charcoal rather than timber. - - - - - - - - - - - - - - - - - - - Ore HearthsVery few remains of documented 16th-18th century ‘ore hearth’ smelters are known, as they were located in valleys and their sites have been re-developed for agriculture or for other industrial purposes. Although now ephemeral, in their day they smelted large quantities of lead and over 75 are documented. Some mill ponds survive, as at Greens Mill at North Lees, and there are ruined structures in the heart of woodland at one site near Froggatt. These smelters were normally fuelled by kiln-dried wood, known as white coal. Many of today’s woodlands in the Derwent Valley, and in the foothills further east, were once extensively coppiced to provide this. In some instances there are hollows, sometimes lined with drystone walls, which mark the sites of the drying kilns.
- - - - - - - - - - - - - - - - - - - CupolasThe 18th-19th century cupola or reverberatory lead smelters where often more substantially built. Also, they are often associated with slag mills for re-smelting and others that made ‘red lead’, an oxide of lead commonly used as a pigment in local colour works and also for dyeing. These industrial-scale smelters, of which about 40 are known, used local coal as a fuel and they had associated stone buildings, long condensing flues with prominent chimneys and reservoir ponds.
- - - - - - - - - - - - - - - - - - - What SurvivesThe visible remains of this important industry are limited, or they have been removed or built over. One notable exception is the Stone Edge Cupola between Rowsley and Chesterfield, where the fine square chimney and fragmentary remains of the condensing flues, other structures and a large pond can be seen. Remains at a few other sites survive, but these lie on private land. - - - - - - - - - - - - - - - - - - - What you can do
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