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.
The only economic tin ore is in the form of a tin oxide (SnO2) called cassiterite (SnO2) known as black 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.
Black tin needs to be smelted by which it is refined to produce metallic tin, known as white tin.
Historical tons of Tin Mined in Cornwall from 1301 to 1875
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 last tin mine in Cornwall was closed in 1998.
Historical price per ton of tin in Cornwall from 1301 to 1886
Death rates of Cornwall tin miners
In early times copper was often cast aside as worthless when working for tin. There are no know copper mines in Cornwall before the 16th century.