Holmans table Geevor Mill.  HES.



Mining technology

The history of mining within Cornwall and West Devon stretches back into prehistory when this area was uniquely-placed to supply the tin vital for the production of bronze in Britain. Likewise, the tin streams of Cornwall and Dartmoor were the basis for an industry which supplied almost all the needs of western Europe during the medieval period. True underground mining is first documented in the Crown-operated silver mines of the Bere Alston peninsula during the late 13th century, but it was not until the early 16th century when the tin gravels of west Cornwall were approaching exhaustion that tinners were forced to turn to the parent lodes, most probably in what were to become the coastal mines of west Penwith.

The mining technologies in use during this period are documented by a number of contemporary European writers, notably Biringuccio (1540), Agricola (1555) and Ercker (1574) and show an industry that had already begun to develop sophisticated water-powered machinery, in particular for pumping, and were using extensive adits to provide natural drainage wherever possible. By 1602, however, Carew was making plain the limitations of the available technology as mines became deeper: 'For conveying away the water they pray in aid of sundry devices, as adits, pumps, and wheels driven by a stream and interchangeably filling and emptying two buckets, with many such like, all which notwithstanding, the springs begin to encroach upon these inventions as in sundry places they are driven to keep men, and somewhere horses also, at work both day and night without ceasing, and in some all this will not serve the turn.'

In Europe in the early 17th century, Giattambista da Porta had speculated on the application of power from a vacuum induced by steam, whilst David Ramsay had taken out a patent 'To raise Water from Lowe Pitts by Fire' in 1624; von Guericke, Papin, Boyle and Morland advanced the new science of steam power to some degree, but the first practical machine specifically for mining use was developed by the Devon engineer, Thomas Savery, in 1698. Some sources suggest that an early example of one of his mine pumps was installed at Wheal Vor, though this is a matter of some debate. Savery's machine was a vacuum pump, however, and it was not until Thomas Newcomen combined Guericke's cylinder and piston with Savery's separate boiler that a workable machine was created. The first engine to be installed at a mine may have been at Balcoath in the first decade of the 18th century, though most experts contend that the first installation was not within Cornwall. The engines were rapidly taken up in the coal mines of Britain and, to a more limited degree, in Cornwall. By the time of Newcomen's death in 1729, his engines were helping to drain mines in Hungary, Sweden, France, Germany, Belgium and Spain, whilst the following decades saw Josiah Hornblower erecting the first beam engine in North America.

Despite work by the Yorkshire engineer John Smeaton which resulted in the doubling of the efficiency of the Newcomen engine, it was proving too fuel-hungry for most Cornish mines, but the development of the separate condenser by James Watt transformed the efficiency of the engine made possible efficient mine drainage. Rotative engines which could be applied to mine haulage were developed in 1781, the use of expansive steam in the following year and double-acting engines soon thereafter. The end of Watt's patent in 1801 allowed local engineers free rein to experiment with further improvements to the beam engine, the development of the Cornish boiler and high pressure working by Richard Trevithick (see also link) being particularly significant and the beam engines which emerged in the early decades of the 19th century were to power Cornish and Devon mines for the whole of the following century.

In 1580, Ulrich Frosse had been charged with exploring the possibility of mining for copper in Cornwall, working initially at Perranporth and Illogan, though ore was also purchased from mines near St. Just and St. Ives. The venture was not a success. Within a few decades copper mining seems to have come to a halt and it was not until the last decades of the 17th century that production was restarted, largely as a result of the efforts of John Coster, a copper smelter who established works on the River Wye in 1680. Coster, a metallurgist and engineer, helped to develop adit drainage, made significant advances in assaying and dressing copper ore, erected one of the first horse-whims in Cornwall and developed the first true copper mine in Cornwall, at Chacewater in the early 1700's.

National demand for copper was rising rapidly and Cornwall proved rich in ore, particularly to the north of Carn Brea. By the 1720's Cornwall was producing 6000 tons of copper ore a year and in the next two decades this was to double. But deeper mines were inevitably wetter mines. Newcomen's engines were put to work on some; others developed adit systems, that begun by Sir William Lemon in 1748 to drain Poldice eventually becoming the Great County Adit and linking together dozens of mines, notably those being newly-developed in the parish of Gwennap. By 1770 Cornwall was producing nearly 30,000 tons of ore each year, but the copper ore raised from two vast opencasts on Anglesey from 1768 was to seriously challenge this growth. The only way to improve the economy of Cornish mines and make them competitive was to improve the efficiencies of their pumping engines. By the end of the century, the Anglesey mines had ceased to be a threat; copper prices were rising and the beam engine had been transformed. Cornish engineers such as Harvey, Trevithick, Woolf and West emerged during this period, new foundries and engineering works were established at sites like Perranarworthal and Hayle. Soon, new ports were being constructed to ship ore, coal and timber and tramways being laid down to serve the mining fields inland. John Taylor's Redruth and Chasewater Railway carried 50,000 tons of ore in its first year. Amongst the developments in mining machinery during these early decades of the 19th century were John Taylor's crushing rolls at Wheal Friendship in 1796, Trevithick's steam winder, erected at Stray Park in 1801, Woolf's steam stamps at the Carn Brea mines in 1813, the Brunton calciner at Wheal Vor in 1830, the introduction of wire rope haulage at South Frances in 1840, Michael Loam's man-engine at Tresavean in 1842 or the Brunton Belt (a forerunner of the belt vanner) at Devon Great Consols in 1844.

Cornish engineers and inventors did not solely limit their efforts to mining technology, however, and the 19th century also saw the emergence of a substantial gunpowder making industry, the invention of safety fuse by William Bickford, whose company was to dominate world production for decades, the expansion of Perran Foundry and Harveys of Hayle into international suppliers of mining equipment and the eventual emergence of Holmans of Camborne as world leaders in the field of rock drills and compressed air equipment. Murdoch lit his Redruth house with gas in 1795, Davy established himself as a pioneering British chemist, Goldsworthy Gurney ran a steam-driven coach from London to Bath in 1829 before turning his attention to light houses, Trevithick had trialled a practical steam carriage in 1801 and produced the first successful steam locomotive in the world. Cornwall during the late 18th century and during the first part of the 19th century was an important centre of innovation and technological development.

In 1836, the Caradon mines were discovered and in 1844, the phenomenally-rich Wheal Maria (with its sister mines, soon to become Devon Great Consols). The mines to the west of Truro had been worked extensively for half a century, however, and were showing signs of incipient exhaustion. In the 1830's Cornwall had dominated world copper production. Two decades later Chile's production far exceeded Cornwall's output, whilst the Lake Superior mines and those in South Australia were developing fast. Cornwall and Devon's peak year for production was 1855-6, when 209,305 tons of ore were mined . By the end of the decade, tin was replacing copper as the most important mineral, particularly in the western mines, and in 1866 the collapse of banking giants Overend & Gurney precipitated a disastrous crash in the copper market which Cornish copper mining could not survive. Chile, Australia, Lake Superior, Montana, and Arizona spelt the end for Cornish copper mines and for the Welsh smelters.

Some Cornish mining districts were fortunate in that they also possessed tin reserves, and through increasing mechanisation and the adoption of efficient ore dressing technologies their mines were able to work on for a couple of decades more, despite falling tin prices; some former copper mines found a new lease of life in working the arsenical pyrites which they had formerly discarded as waste - indeed Devon Great Consols produced a substantial proportion of the world's arsenic during the closing years of the 19th century. Nevertheless, the great days of Cornish mining were over and one by one, mines whose reputation had spread far beyond Cornwall were abandoned forever.