Tin Mining

Valuable metal such as tin and copper only make up a small percentage of the earths crust. For these to be viably collected they have to be concentrated by natural processes such as alluvial deposits or by geological processes such as the local granite formation.

In this part of Cornwall, the rich metal deposits are associated with the local granite formation. While the granite was hot magma, the minerals became concentrated in high temperature liquids and gases, which as the temperature fell formed mineral veins.

Due to the igneous geology of this area, mineral lodes of tin, copper, iron, zinc, lead and to a lesser degree, silver were formed. All of these metals were in sufficient amounts to be mined.

Tin has been produced and traded in Cornwall for over two thousand years. Trading occurred in pre history times but from this period little is known. There are legends of the Phoenicians trading with the Cornish for tin.

Image reproduced by kind permission of
Penlee House Gallery and Museum.

Tin Ingot Found at Trereife

A tin ingot was found at Trereife. On it can be seen raised lettering, E I C and a symbol resembling an elaborate Chi Rho.

The Chi Rho cross is an early representational form of the cross. It is comprised of the letters X and P, in Greek are the first two letters of Christos (Christ).

More recent than Roman, as the marks are very similar to those of a West Country Merchant’s Marks. Found ar Trereife in 1845.

Early Mining and Streaming

The early tin industry would have been based on alluvial deposits. This is where streams had eroded down through the surface and cut across tin seams. The tin was then washed out forming alluvial deposits.

Collection of the ore could be carried out via the streaming of these deposits. Using water enabled the heavier tin bearing minerals to be separated from the other minerals. Originally the tin was manually panned, later technology intervened and settling pits were used.

Tin has been mined since the Medieval Period. The first lodes were those easily accessed i.e. those exposed at the surface. When the surface lodes and alluvial deposits became exhausted mining was forced to go underground.

Stannary Parliament

England was going though troubled times during the reign of King John. He required the support of the Cornish tin miners. This provided the opportunity for them to flex their political muscle. They negotiated with the king to grant them special privileges, which were encapsulated in a Tinners Charter. Tin miners could now mine on any land that had not been enclosed; and legally excused from normal tax and military service. The miners were now under a Stannery Parliament.

Copper Mining

When one thinks of mining in Cornwall it is typically associated with tin. When mining was at its peak it was for copper. In the eighteenth century copper mining became of greater importance than tin and Cornwall by the early nineteeth century was the greatest producer of copper in the world.

The affect of copper mining on Cornwall was drastic, demand for the metal was high with the industrial revolution. Prices were good and copper reserves were large with little competition from elsewhere in the country. When mining was at its peak it employed up to 30% of the county's male workforce. It was a huge industry even to the degree that copper was smelted here. It later became more economical to smelt the copper in coal mining areas. It being cheaper to transport the ore rather than bring in the coal.

Copper had an effect on the county's economic infrastructure. Large quantities of ore were moved, ports upgraded and eventually railways were built. A local example is the Hayle railway which later became the West Cornwall Line.

With the discovery of huge deposits elsewhere in the world in the mid nineteenth century, the price of copper fell and by this time the best Cornish deposits had been mined out. Mining in Cornwall was in a dire state but fortunately tin had been found in some of the deeper Cornish mines. Due to the mineral zoning, many copper mines also had tin deposits, but miners had to go to deeper levels. Tin now fuelled a mining boom.

Tin Mining

With the copper lodes being almost vertical, the mines were going progressively deeper and fortunately many ran into tin deposits. When copper was no longer viable it was possible to continue to mine by changing to tin.

Deeper mines led to greater problems with drainage and higher costs, but mining was still viable. The tin industry could not replace the importance of copper mining to the local communities. It was on a smaller scale requiring a considerably smaller workforce.

As for copper, cheaper deposits of tin were found overseas, and by the end of the nineteenth century tin mining had severely declined. A few struggled on until the 1920s, aided by the new value of tin mining by-products such as arsenic.

Geevor was a working mine until 1990, and provided much needed employment in the region.

Benefits to Cornish Engineering

The problems of drainage, and the benefits of large profits, drove the development of large powerful steam engines. Many were built locally in such places as Hayle and the industry expanded to produce engines for export. Cornish technology could be found at mines all over the world.

International scientific reputations were made in the development of new innovations in steam engineering, such as that of Richard Trevithick's high pressure steam systems.