Great Work mine

Tin works, probably on the surface and in shallow pits, were recorded here from 1538. Deep mining began in 1816 and continued (with some breaks) until 1930. My blip shows the engine house, built around 1829, to house the pumping engine that extracted water from the mineworks. My first extra shows the stack and my second extra is the robust metal grating over the mineshaft (preventing people from falling in, but enabling roosting bats to come and go, and also keeping the mineworks ventilated).