Mining in Cornwall and Devon tin was found as alluvial deposits of cassiterite in the gravels of stream beds. Eventually tin was mined underground; underground mines sprang up as early as the 16th century. Tin lodes were also found in outcroppings of cliffs. Tin is one of the earliest metals to have been exploited in Britain. Chalcolithic metal workers discovered that by putting a small proportion of tin (5 – 20%) in molten copper, the alloy bronze was produced. The alloy is harder than copper. The oldest production of tin-bronze is in Turkey about 3500 BC, but exploitation of the tin resources in Britain is
Sundown Tin and Copper Mine to calcine the tin concentrates and drive of arsenic and sulphur. In 1917 a Merton calciner was erected and flues for arsenic recovery constructed. It is likely that these replaced the old reverberatory furnace and calciner. Arsenic became and important product of the mines, the demand escalating during the prickly pear infestation. New shafts were sunk at both the tin and copper mines. The lack of water reduced output in 1918, only 23 tons of tin and 12.5 tons of copper concentrates being produced, but the new shafts were continued, the three compartment copper shaft having poppet legs and ore