Underground Exploration: Hard Rock
By the mid-15th century, as alluvial works were running out, the value of tin was increasing and technology was improving, so miners started to follow the tin lodes underground.
Cornish rock is hard; this was a major problem to the early Cornish miners. Tools and methods had to improve before miners could go underground to any depth.
Over the centuries, mining became a highly technical operation. The deeper miners went underground, the more there was a need for well designed and well made equipment to ensure efficiency and safety. The mining industry was a leader in technological development especially in Victorian times, and as so often happens, it was largely the mine owners that benefited from this and not the workers.
Not everything changed, however. Much work was still done by hand due to the low wage costs and large numbers of employees. The basic equipment underground changed over time, so picks, hammers, shovels and tull hats were still in common use well into the 1900s, when compressed air drills became more popular.
Evidence of the early mines are scarce, their surface structures having been largely destroyed or replaced by later workings. At the nearby coastal workings of Botallack and Levant some structures do survive. Entrance and drainage tunnels, called adits, can be spotted in the cliffs.