For many people outside the parish, the terms “Mountfield” and “Gypsum Mine” are synonymous! We all know there is much more to Mountfield than gypsum mining, however, we must concede that it continues to play a significant economic and social part in parish life. The discovery of gypsum (calcium sulphate) in Mountfield in 1872 came about by chance, the target of the borings was coal. In its natural state gypsum is a rock found in seams, which are several feet thick and crushed into powder, in fact it is mined in a similar way to coal.
The Sub-Wealden Gypsum Company Limited was formed on 10th May 1876 and mining started with the sinking of a shaft in Limekiln Wood. Progress was initially slow because of the isolated location, until a railway link had been constructed to the main line at Robertsbridge. Gypsum mining then developed into the largest industry in the area and gypsum continues to be in great demand by the building industry to make plaster and plasterboard.
During the 1890s the mine’s workforce rose from 15 the 27 underground and 22 to 60 on the surface. However, despite increased production the value of gypsum did not rise proportionaly and this probably lead to the winding up of the Sub-Wealden Gypsum Company. After a short stoppage in 1906-7, during which working methods were thoroughly overhauled, mining resumed on a larger scale. Production rose again after the Second World War and the winding shaft was replaced with a sloping adit with and electrically operated railway system. In the early 1950s a second, larger mine opened at Brightling. Because of the scenic value of the surrounding countryside and the unsuitability of local roads for heavy freight, the two mines were linked by an overhead cableway. This allowed gypsum from the Brightling Mine to be taken to the processing plant at the Mountfield Mine. The cableway was subsequently replaced by a covered conveyor belt system.
Today the mines are extensive and several times larger than the 6′ by 7′ tunnels of earlier years. Modern day miners travel underground by Landrover. There are probably another 20 years reserves of gypsum remaining – the Brightling Mine has a mining capacity of 1m tonnes pa (mining at Mountfield was abandoned in 1990) and the Mountfield/Brightling reserves, mined by British Gypsum are the largest in the UK.