Oliver's Mill.

This is a calcining bottle oven. They were used for firing flint stones for subsequent grinding, or milling. The finely ground flints could then be added by pottery manufacturers to their clays to give whiteness and greater strength to their finished products. 
This oven was built in 1909. It was last fired over 50 years ago. Another example of the decline of the pottery industry in Stoke on Trent.