A gradual transition within the salt industry took place from the 1880s, and particularly with the collapse of the Adelaide mine in 1928 bringing an end to rocksalt mining in Northwich. In the late 19th Century, only a relatively small contribution, circa 10% of total production, was made by pumping centres outside Northwich, but this was to change. Independent firms had established themselves in Lawton, Middlewich, Sandbach (Malkins Bank) and Lymm and they were thriving due to the use of more modern equipment and techniques compared with the obsolete methods still used in Northwich and Winsford. By the 1930s older businesses had closed and the pumping of natural brine was extensively carried out in locations in mid-Cheshire away from Northwich and Winsford. However, the extension of brine pumping into more rural areas went hand in glove with progressive surface subsidence spreading through the rural areas around the new centres of pumping.
As a result of the increased pumping and subsidence outside the Northwich Compensation District, the need to introduce a compensation scheme throughout mid-Cheshire was pursued in the 1920s and recommendations were made to Cheshire County Council in 1934 that one Compensation District should be established to cover the whole area liable to brine subsidence. Progression of this matter was delayed by World War II, but in 1950 the Ministry for Town and Country Planning produced a paper entitled “Development Plans, Rocksalt and Brine”. This document provided the basis for county policy which led eventually to the passing of what became the 1952 Act.