Combe Martin Village HistoryThe history of Combe Martin, North Devon 2023

Combe Martin Ores, Smelting and Milling

By Combe Martin History and Heritage Project ©2023-2024

Modified on June 13, 2024

Abstract

Until archaeologists conducted three test pit excavations in 2001-2002, there was no archaeological proof of early post-medieval lead smelting connected to the Old Combmartin polymetallic mining industry.

However, Combe Martin's industrial activities also came with significant environmental impacts. The smelting of lead and silver ores would have released harmful pollutants like sulfur dioxide into the local air and waterways.

These created enduring risks to the health of Combe Martin's residents and the surrounding ecosystems. The extensive mining and quarrying also likely led to landscape degradation and disruption of natural habitats.

The most valuable ore deposits contain metals crucial to industry and trade, such as silver, copper, gold, and iron. These are often called 'noble' ores. The primary production of silver requires the smelting of ores by furnacing.

The first two lead-smelting pits were located in the garden of the historic 'Christmas Cottage' (NGR: SS 5868 4631) near Combe Martin St Peter ad Vincula Church. The third was across the road in the garden of a property called ‘Middleton’.

All three pits yielded large amounts of glassy, opaque waste, otherwise known as slag, in shades of grey, green, and blue. This slag was likely a by-product of lead smelting.

John Allan from Exeter Museum Services dated the slag-rich deposits to the 16th and 17th centuries, based on associated pottery and clay pipe fragments.

The evidence from the excavations was published in academic papers. Trevor Dunkerley, along with Sarah Paynter and Peter Claughton, published their findings in a paper titled Further work on residues from lead/silver smelting at Combe Martin, North Devon.

Introduction

The available academic papers outline the history of lead-silver mining, smelting and refining, at Combe Martin during the 16th and 17th centuries. A paper titled Lead Smelting Waste from the 2001-2002 Excavations at Combe Martin, Devon was also published by Dunkerley, Paynter and Claughton.

Subsequently we have a detailed analysis of the slag from the smelting of silver-rich lead ore, produced in the 16th and 17th centuries, recovered during the Combe Martin excavations.

We have a comprehensive overview of the archaeological evidence and historical context of lead-silver smelting at Combe Martin, and the processes employed.

The colour of slag or waste, a by-product of smelting, is influenced by the minerals present in the ore and the smelting process. For instance the presence of sulphide reacting with other compounds can lead to a blue-green colour.

In what is thought to be an ore hearth smelting operation, significant quantities of coal were also discovered. This operation, which processed lead-silver ores, dates from the late 16th century to around 1690. An ore hearth smelting operation is a historical method used for smelting lead and other ores.

Ore hearth smelting was developed around the mid-1500s; it was efficient and less wasteful, leading to its widespread adoption. The operation involved burning dried wood and sometimes a bit of coal or peat as fuel.

The smelting process occurred in two basic steps, often with secondary processes like roasting the concentrate to remove moisture and some sulphur.

The discoveries at Combe Martin imply that coal was used as fuel for silver/lead smelting, up to a century before it became common in lead smelting with the reverberatory furnace, and possibly 200 years earlier than previous evidence for its use in the ore hearth

Combe Martin was also exploited for iron, and the peak of local iron production occurred between 1796 and 1802. There is a grade 2 listed Mine Forge, built in 1837, at the central hub Old Combmartin Mines on Bowhay Lane.

The remnants of local mining are not extensive landscapes, but they include obvious human-sized holes in the coastal cliff faces. Most inland remains have disappeared under private residences, but Harris’s mine has been excavated, and the base of the engine house of William’s Shaft is visible.

There are visible remains of the Grade 2 bob (beam) wall and basement levels of William’s Shaft engine. The engine house was constructed to pump the 27 fathom (162 ft) deep Williams Shaft, which is located midway between the Old Combmartin Mine (downslope) and Harris’s Shaft.

A 50" cylinder steam engine, manufactured by the Cornish Copper Co, Hayle, was installed in March 1837. It pumped at a rate of 10 strokes per minute to drain several mines in the parish.

The engine seems to have been relocated to the Cornwall Gold and Tolgus Mill, Redruth. For more information, refer to Exmoor’s Industrial Archaeology, Exmoor Books, 1997, edited by Mick Atkinson. The relevant chapter is authored by Peter Claughton.

Director’s shaft (at SS 588643), Bowhay Lane, Combe Martin, Ilfracombe EX34 0JN, was pumped using flat-rods connected to the balance bob at this site. The Combe Martin Silver Mines Society offers guided tours of the excavated levels, usually on Thursdays and Sunday mornings.

Documentary Evidence

There is documentary evidence of lead-smelting and silver mining around Combe Martin (Claughton, P., 1989, 1992 and 2003), especially after the Crown got directly involved in silver mining at the end of the thirteenth-century (Centre for Archaeology Report 79 2003).

Slag from the smelting of silver-rich lead ore produced in the sixteenth or seventeenth centuries, was recovered by local volunteer archaeologist Trevor Dunkerley, during excavations in Combe Martin in 2010.

Samples of slag from nineteenth-century smelting in Combe Martin were also found and used for comparison. The 2010 report on lead-smelting waste in Combe Martin was published by Research Gate.

Combe Martin's Mineral Resources

Combe Martin took advantage of its wealth of local ores and minerals, and profits were reaped by several monarchs, entrepreneurs and prospectors. Ore is natural rock or sediment containing valuable minerals; typically with metals that can be mined.

The ores within veins or sheets are treated, and sold at a profit to satisfy a myriad demands and belief systems. Our sources are listed at the bottom of this page.

Natural minerals, pigments, and precious metal ores have long been in high demand. There were smelting blast furnaces and mills in Combe Martin from late medieval times, as well as corn mills and waterwheels.

A Short History of Milling

A blast furnace is used in smelting to produce industrial metals, which were generally pig iron but also lead and copper. 

By Domesday 1086 there were approximately 6,000 watermills in England (Open Domesday) with none recorded in Combe [Martin] at the time. These mills  required a steady stream of water and were erected in valleys.

Extensive earthwork dams and reservoirs were built to store and control sufficient water supplies. Impervious materials were used to form a core, and permeable substances were laid on the upstream and downstream sides.

The word smelt originates from the mid 16th century: from Middle Dutch, Middle Low German smelten and is related to the verb melt. Smelting is simply the process of applying heat to an ore in order to extract a base metal.

The mining process removes the ore from the surrounding waste rock, and  smelting obtains pure metal from its ore by heating it to a higher temperature.    

Milling separates the valuable minerals from the gangue of no value; and  smelting breaks down the minerals to yield the pure metal (Shantz, Robert F., 2015).

Combe Martin's Smelters

Combe Martin's smelters are lost to weather, erosion or destruction, but a  smelting mill house was formerly located on Borough Rd, Combe Martin. The smelting site is now occupied by Loverings Garage. 

That silver-lead smelter was operated by Combmartin and North Devon Smelting Co. Ltd, who worked West Challacombe Mine during 1845-1851.

The original building (walls re-roofed destroying original clay tile pantile roof) has or had the remains of a flue, up hillside to southwest (Claughton, 1998).

A fuel source is required to generate the temperatures hot enough to melt the lead from the galena (silver-bearing lead-ore). Initially this was achieved by coppicing nearby woodland, such as Exmoor bordering Combe Martin. 

Later, fuel came from harvesting and drying abundant supplies of moorland peat. In larger industrial smelting mills: tall chimneys and flues diverted smoke, poisonous sulphur dioxide and lead gas by-products, into the atmosphere.

To support combustion, hand bellows were used to supply a steady stream of air. Mechanisation took over, and waterwheels began to power enormous bellows. 

Excavations in Combe Martin Between 2002-2010

Lead smelting waste was discovered during excavations near Combe Martin parish church, during 2002. "Slag [stony waste matter] from the smelting of silver-rich lead ore, produced in the 16th / 17th centuries, was recovered by Trevor Dunkerley". Read more at Historic England.

Excavations and results at Christmas Cottage on Church Street, published by Paynter, Claughton and Dunkerley in 2010, revealed undisturbed accumulations of material from the early medieval period to the present day.

The material found near Combe Martin war memorial included dense, heavy, black and grey green smelting slags, thought to be Lead-ore-smelting slag from argentiferous Lead-sulphide. Also found were large quantities of quartz.

Historically used in glass, and in fused silica, concrete, and mortar: quartz crystals have been used to make oscillators for radios, computer chips, and clocks. Quartz crystals are also valued for their beauty as mineral specimens and gemstones.

Refining Ores by Cupellation 

Cupellation is a refining process in metallurgy. Ores or metal alloys are treated under very high temperatures, and subjected to controlled operations, to separate noble metals such as gold and silver, from lead, copper, zinc, arsenic,  antimony, or bismuth, present in the ore.

In other words, melting impure metals in a cupel separates gold or silver from impurities. When they are heated at high temperatures, the precious metals remain apart, and the others react, forming slags or other compounds.

The North Wales Pentrwyn site - near the Great Orme Mine - is currently the only known British Bronze Age (circa 2500-700 BCcopper smelting site (ResearchGate, 2023).

Once a hive of human activity, it is estimated that up to 1,760 tonnes of copper was mined at that North Wales location during that period.

The site lies on the east side of Great Orme’s Head peninsula, Llandudno, on the headland of Pentrwyn at SH 7812 8377 (Craig-y-don, Llandudno, Conwy, Wales, LL30 2QL) .

The Most Common Methods for Smelting

After the ore had been separated from any rock and vein minerals, the concentrated product was taken for smelting. From the mediaeval period to the early twentieth century, three principal methods were used.

Beginning with rudimentary holes in the ground: bales (or boles), ore-hearths, and reverberatory furnaces heated the ore with a flame from a separate chamber (Northern Mine Research Society, 2023).

Combe Martin's Ironstone Workings

Evidence of mineral workings can be found around Combe Martin, and ironstone was worked on the cliffs near Little Hangman, Blackstone Point and Girt Down. The remains comprising earthworks are thought to include adits and spoil heaps.

The Combe Martin workings and trenches are visible on aerial photographs and maps. More information on Combe Martin's mining monuments can be found at Historic England Heritage Gateway online.

Combe Martin Iron-Stone Sent to South Wales

From the year 1796 to 1802 a considerable quantity of rich iron-stone was sent annually, from the neighbourhood of Combe Martin to South Wales iron-works at Llanelly. The quantity sent in the seven years was 9293 tons. "None had been shipped since 1802" (Lysons, D., 1822).

About Silver Smelting

Smelting is the ancient art of extraction of metal from its ore by a process involving heating and melting. In this case, silver-rich ores. Silver sulphides are the most easily found ores, and those are typically mixed up with the lead sulphide argentiferous galena.

Smelting argentiferous (silver-bearing) lead-ore produces a lead-silver alloy. The silver content is then separated from the lead and the rest.

Combe Martin Umber

Umber, an iron-oxide mineral pigment for making paints, was also quarried in Combe Martin. The village river and valley were named after it. There was once a hut behind Lovering's Garage, which was used for burning umber (Beaumont, G.F, 1981, p.13).

Burnt umber was calcinated by heating raw umber, dehydrating the iron oxides which changed to reddish haematite, a heavy and relatively hard oxide mineral. Essentially, it's all about roasted purification.

Haematite is rich in iron and was very popular with the Victorians. It was used in jewellery and often worn during periods of mourning. For millennia, the stone has been valued for its protective, magical, and healing properties. Moreover, haematite was discovered on the ‘Red Planet’ by NASA in 2001.  

Burnt umber has long been used for both oil and water color paint. Rembrandt used umber for his rich browns. Caravaggio (1571-1610) famously created graphic traces with burnt umber during the baroque period.

Baroque artists considered umber to be warm and more harmonious than darker shades. In the 19th century, the Victorian colour palette was dark, with rich and deep shades of maroon, red, burgundy, chestnut, dark green, brown and blues.

Umber shows up throughout history - it was one of the first pigments used by humans. Along with charcoal it's what made cave paintings in the Paleolithic period.

Early Smelting Practices

Smelting produced lead with the silver dissolved in it. Silver was and is exceedingly rare, and thus expensive; Combe Martin Mine Tenement's silver content, once reported at "sixteen per cent", was highly prized by Edward Longshanks and by Elizabeth I.

Early on, silver-lead ore was broken up by hammers, washed in troughs, often by women, and then smelted in a bole (like a lime kiln with a chimney and draught) by bolers or furnacemen.

The furnaces were not expensive and did not need much investment for short-term and/or exploratory smelting operations. Boles were primitive in mediaeval times and much later.

Ore Hearths 

Sixteenth-century ore-hearths burnt less fuel and could smelt smaller pieces of ore. This process was so economical that the technology rapidly spread across the industry (Northern Mines Research Society, 2023).

Galena or Lead Sulphide

Galena, also called lead glance or black ore, is the natural mineral form of lead sulphide. It is the most important ore of lead and an important source of silver. It can be used as a source of lead in ceramic glaze.

Lead is very malleable, ductile, and dense and is a poor conductor of electricity.  Silver is the best conductor of electricity, because its electrons are freer to move than those of the other elements.

Smelting Boles and Hills

The primary function of boles or bales was to convert raw lead ore into lead 'pigs'. Simple boles comprised a hearth surrounded by a stone wall (bole hearth), with a wind tunnel in the side facing the prevailing wind. On a base of logs were piled layers of brushwood and crushed ore (or bing).

A bole hill was a primitive type of lead smelting facility commonly used in Britain prior to the 17th century. There had to be a good supply of logs and brushwood for a Bole to work.

Not to be confused with Beehives and Bee Boles, Historic England lists Bee Boles at the village "Pack o' Cards Inn, including courtyard walls incorporating Bee Boles on the northwest side, Combe Martin High St." (LEN 1169072).

Combe Martin's Bee Boles are monuments but they have nothing to do with smelting.

The smelting bole was fired when the wind was favourable. Smelting can also be done with charcoal or coke, but it is not necessary for silver-lead smelting. 

Charcoal may burn hotter and longer than wood, but it takes longer to reach the right temperature, up to half an hour. The maximum temperature of a charcoal grill is 1200 °F (IAS Institute, 2022).

These smelters were built near the top of hills to harness the stronger air currents experienced at elevated altitudes; they used locally-felled timber to fire their furnaces. The lead ore at the surface required smelting to separate the lead from the ore.

Early bole smelting methods were very simple; early miners would light a fire in a shallow dug-out in the ground, on the side of a steep slope or exposed area. The bole would be filled with large pieces of ore and wood before being lit.

This could only be under done favourable prevailing conditions (Stoney Middleton Heritage, 2022). Bole smelting was imperfect and dependent on uncontrollable factors; by the late 16th century, boles did not depend on wind power.

Simple bellows, initially manually and foot-operated, were used to provide the draft or blast to an ore hearth, to get the fire burning quickly and with enough heat to melt the lead. 

The bole required a good draft of air which was why they were positioned on a slope to encourage an updraught. The fires were left to burn for two days or more, by which time the lead would have melted and run to the bottom of the bole. 

Once the lead was cast into pigs, moulds or trenches, and stamped, it was handed over to wardens or overseers of the mine. Casting "Pigs" are so called because the visual effect resembles a sow and her piglets.

The silver was finally extracted by melting on an open hearth causing the lead to be oxidised and absorbed in the porous body of the earth (Stuckey, 1965, p.6).

Conclusion

The archaeological excavations and historical research have provided valuable insights into Combe Martin's rich industrial heritage, particularly the area's long history of lead and silver mining and smelting.

The discovery of slag and other evidence from 16th and 17th century smelting operations confirms that Combe Martin was an important center for the production of valuable metals like silver and lead.

However, this industrial activity also came with significant environmental impacts. The smelting of lead and silver ores would have released harmful pollutants like sulfur dioxide into the local air and waterways.

These posed risks to the health of Combe Martin's residents and the surrounding ecosystems. The extensive mining and quarrying also likely led to landscape degradation and disruption of natural habitats.

The use of coal as a fuel source for the ore hearth smelting processes is an especially significant finding, indicating that Combe Martin was at the forefront of technological developments in metal production, centuries before the widespread adoption of coal-fired furnaces.

This underscores the importance of Combe Martin's mineral resources and the ingenuity of its early industrial workers, but also highlights the growing environmental toll of industrialisation even in this relatively remote corner of England.

While the physical remains of Combe Martin's mining and smelting heritage have largely disappeared over time, the scholarly research and archaeological evidence help piece together this vital chapter of the village's history.

Ongoing efforts to preserve and share this knowledge, such as the guided tours of the excavated mine sites, ensure that Combe Martin's industrial legacy will continue to be appreciated by residents and visitors alike.

The story of Combe Martin's ores and smelting operations is a testament to the resourcefulness and entrepreneurial spirit that has long defined this unique corner of North Devon, even as it grappled with the environmental consequences of its industrial development.

Read the Northern Mines Research Society article on Smelting (opens new tab).

Find out more from Combe Martin Silver Mines Society (opens new tab).

Also see: Combe Martin Lime-Burning and Quarrying

Contact or visit Combe Martin Silver Mines Society (CMSMS)

© Author 2023-2024

Article first posted April 2023

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Shantz, Robert F. (2015): Mining, milling, and smelting operations in southwest New Mexico. New Mexico Geology, v. 1, n. 2 pp. 24-26, Print ISSN: 0196-948X, Online ISSN: 2837-6420

Stoney Middleton Heritage (2023): "Lead Smelting".

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