tin

Pendarves tin mine, Cornwall. Tin has been mined in Cornwall for thousands of years, but the Cornish tin-mining industry peaked during the 19th century, and has since declined. Foreign competition in the 20th century made Cornish ore increasingly unprofitable. The last working mines, including this one at Pendarves near Camborne, closed a few years ago. A few sites have been reopened as heritage centres.

Cornish tin miners in the pit. Illnesses such as bronchitis, consumption, and rheumatism were common among the men who worked underground, and by the age of 40, many miners were no longer fit to work. Death and injury were accepted hazards of the job. The Cornish tin mines did, however, inspire several safety-based innovations, such as the miner's safety lamp, invented by Penzance-born Humphry Davy.

The Levant Beam Engine, near Pendeen in Cornwall, is more than one hundred and fifty years old. Originally used to pump water out of the tin mine below ground, and to bring ore and miners up to the surface, the engine lay idle for 60 years, before being restored to full working order in the 1990s as a tourist attraction.

Soft, silver-white, malleable and somewhat ductile, metallic element, symbol Sn, atomic number 50, relative atomic mass 118.69. Its chemical symbol comes from the Latin stannum. Tin exhibits allotropy, having three forms: the familiar lustrous metallic form above 13.2°C/55.8°F, a brittle form above 161°C/321.8°F, and a grey powder form below 13.2°C/55.8°F (commonly called tin pest or tin disease). The metal is quite soft (slightly harder than lead) and can be rolled, pressed, or hammered into extremely thin sheets; it has a low melting point. In nature it occurs rarely as a free metal. It resists corrosion and is therefore used for coating and plating other metals.

Tin and copper smelted together form the oldest desired alloy, bronze; since the Bronze Age (3500 BC) that alloy has been the basis of both useful and decorative materials. Tin is also alloyed with metals other than copper to make solder and pewter. It was recognized as an element by Antoine Lavoisier, but the name is very old and comes from the Germanic form Zinn. The mines of Cornwall were the principal Western source of tin until the 19th century, when rich deposits were found in South America, Africa, South-East Asia, and Australia. Tin production is concentrated in Malaysia, Indonesia, Brazil, and Bolivia.