The success of the copper and tin mines in Cornwall created a demand which led to the establishment of local ancillary industries, like smelting. But how did the smelting process work, and what impact did it have on the local economy?
How does smelting work?
Smelting is the process of extracting a metal (like tin or copper) from its ore. Most ores are a chemical compound of metal with other elements, like or oxygen sulphur. Smelting uses heat and a reducing agent, like coal, to remove these other elements from the metal.
Money was often advanced to mines or miners and repaid in tin.
Most tin ore is cassiterite (SnO2), a simple oxide of tin. It’s a particularly heavy ore – approximately three times the weight of a comparably sized piece of the granite (in which it’s normally found).
Most of the early important tin smelters were concentrated in Penzance, Hayle, Truro and the St Austell area. Later, when rail transport had developed, Redruth became an important centre for tin smelting.
The development of tin smelting
Tin was traditionally smelted in blowing houses. Inside, the furnace was kept to temperature using bellows powered by a water wheel. In 1702, this changed dramatically with the introduction of the reverberatory furnace at Newham (Truro) – a landmark technical improvement in Cornish tin smelting. The reverberatory furnace used coal instead of charcoal. This meant the tin ore could be reduced just by using heat, so it was no longer mixed with and contaminated by the fuel. By the 19th century, most tin smelting was conducted in reverberatory furnaces, although the larger and more important blowing houses remained until the mid 1800s.
From tin smelting to banking
Tin smelting in Cornwall was, on the whole, a more capital-intensive and lucrative business than mining and was controlled by a ring or cartel of a few families, particularly the Daubuz, Williams, Harvey and Bolitho families.
Money was often advanced to mines or miners, to be repaid in tin. For the Bolitho family of Penzance this practice led to them becoming bankers. Thomas and William Bolitho founded The Mounts Bay Commercial Bank in 1807 in the count-house of their Chyandour Smelting House. The Consolidated Bank of Cornwall was taken over by Barclays Bank in 1905.
Tin smelting in Cornwall was a more capital-intensive and lucrative business than mining.
The ownership of smelting houses, and of the smelting companies themselves, changed frequently throughout the 19th century as industrial families changed their alliances and strategies.
Copper smelting was a technical, complex process which needed a large amount of copper ore – so initially it made sense to smelt it near where it was mined. The process also used large amounts of coal, both for fuel and as part of the reduction process.
Copper was smelted in several locations around Cornwall, but principally by the Cornwall Copper Company at Hayle (1758-1819). However, later on it made better commercial sense to ship the ore to the coalfields as the cost of transporting coal rose.
From Cornwall to Swansea – shipping the copper ore
Shipments were mostly of hand-picked, crushed (cobbed) raw ore but later partly smelted regulus (an impure intermediate product) was sent too. At first it all went to Bristol, but later most of the copper smelting works were located close to the south Wales seaboard around Swansea.
The transport of millions of tons of copper ore accounts for the once extensive mule trade, the tramroads and railways, quays, industrial harbours and shipping fleets. The ‘Welsh Fleet’ brought coal for Cornwall’s steam engines as back loads in the copper-ore schooners.
In the Swansea region, copper smelting (and indeed much of the tin-plate industry) was in the hands of Cornish industrialists. The Williams family bought the Morfa Copper Smelting Works in Swansea in 1831. Michael Williams (1784-1858) took on the responsibility for the Welsh business and even became High Sheriff of Glamorgan in 1840.