These are the two engine houses originally operated by Crown Mines at Botallack. The deepest shafts are about 500m below sea level. It is sobering to think about the miners so deep under ground and under the sea as well.
The Botallack mining structures are former tin mines perched on the cliffs north of Botallack. The mines extended out beneath the sea bed. The BBC 2015 television series Poldark was partly filmed in Botallack.