Mould stone by the Upper Blowing House Yealm Head

This photograph is dated 28 January 1888. It shows evidence of the tin mining industry which operated on Dartmoor until around 1939. Blowing houses (sometimes called blowing mills) contained small blast furnaces into which a forced draught of air was blown using waterwheel-powered bellows. Cassiterite (tin oxide) ore was smelted in the blast furnace and cast into ingots using the mould stone.