Medieval and modern mining Middle Ages There is no record of tin mining in Domesday Bookpossibly because the rights were Crown Property. For the first half of the 12th century Dartmoor provided most of the tin for Europe, exceeding the production of Cornwall.
In he agreed that “all the diggers and buyers of black tin, and all the smelters of tin, and traders of tin in the first smelting shall have the just and ancient customs and liberties established in Devon and Cornwall. A charter confirming the miners’ rights was granted by King John in The alluvial silt record in the Erme valley, Devon, shows aggradation of tin waste between AD and Silver mining became a major industry, particularly in the Tamar valley around Bere Ferrers in Devon,  following the transfer of power to the Norman lord Robert, Count of Mortain who held the manor of Trematon.
Profits from rights to the silver mines for the crown led to the rise of the ancient Cornish Edgcumbe family at Cotehele and later Mount Edgcumbe. Water was used to operate “stamps” to crush the ore, the lighter waste being washed away. The mineral “black tin” was placed in furnaces and layered with peat. The molten metal was poured into granite moulds which produced ingots of tin. These were taken on pack horses to the Stannary towns for assaying.
Usable deposits in Devon became worked out and so Cornwall was then the center of tin production. In Cornish tin production was tons but in it had been reduced to tons by the Black Death. In Cornish production rose to tons. The tin works of Devon and Cornwall were of such importance that the medieval kings established Stannary Courts and Parliaments to administer the law in Cornwall and part of Devon. This levy was resented for the economic hardship it would cause; it also intruded on a special Cornish tax exemption.
The rebels marched on Londongaining supporters as they went, but were defeated at the Battle of Deptford Bridge. Quarrying was of very limited importance in medieval Cornwall.