© Kelham Island Museum
- The Gannister Mill and Bessemer Converter. The Gannister Mill was used to grind ganister rock, a type of sandstone, into a paste which was used to seal joints inside furnaces. The Bessemer Converter is one of only three converters left in the world. It was used by the British Steel Corporation in Workington until 1975(4?) and produced the last Bessemer Steel made in Britain in 1974. It was brought to the Museum in 1978 as an example of the revolutionary steelmaking process which first took off in Sheffield.