Mining

Tin

Early metal workers discovered that adding a small amount of tin in portions of 5 to 20 percent to copper produced bronze. Copper by itself is soft and easy to bend. Tin has a low melting point of 232'C compared to the melting point of 1538'C of iron. The Bronze age lasted 2000 years before smelting of iron ore become feasible.

Mining of tin in Britain started around 2000BC. Cornwall and Devon produced most of Britain's tin and copper up to the 20th century.

The only economic tin ore is in the form of a tin oxide (SnO2) called cassiterite (SnO2) known as black tin. Black tin needs to be smelted by which it is refined to produce metallic tin, known as white tin.

Placer deposits are the historical starting point of tin mining. The mineral occurs extensively as surface deposits in Cornwall. These are sediment concentrations in stream valleys and along shorelines. The hardness of cassiterite survives stream transport and its high specific gravity causes to concentrate in deposits.

When placer deposits ran out the miners followed the tin underground. The transition from placer to underground mining occurred between the 1500's and 1750's.

The last tin mine in Cornwall was closed in 1998.

Historical tons of Tin Mined in Cornwall from 1301 to 1998

Historical price per ton of tin in Cornwall from 1301 to 1952

Death rates of Cornwall tin miners

Copper

In early times copper was often cast aside as worthless when working for tin. There were no know copper mines in Cornwall before the 16th century. Cooper mining ceased in Cornwall around 1991.