sentences:  ICI were contracted to excavate the salt cavities while Shell was contracted to carry out all the other associated engineering works.These were extensive and included all the necessary ancillary facilities, connecting the Plumley site to the existing pipeline system, to the Shell refinery at Stanlow and to a new storage depot to be built at Goostrey.Following the Suez Crisis of 1956, the Ministry of Power decided that the storage capacity at Plumley should be doubled.