Butterley Company correspondence file with the Francois Cementation Company Limited, relating to the sinking of shafts at Ollerton Colliery The Francois Cementation Company of Bentley Works, Doncaster, won the contract to sink Shafts Nos. 1 and 2 at Ollerton. Most of the correspondence relate to the sinking of the shafts with the contract being completed in Sep 1925. Some later letters relate to concerns about shaft linings raised in the press elsewhere, Aug-Oct 1929. Feb 1923-Mar 1934