THE DERELICT MISCELLANY

Dorking Greystone Lime Works

The Grey or Middle Chalk outcrops above the villages of Brockham and Betchworth forming the huge tree-covered bulk of Box Hill, rising to 735 ft (224) at its peak. Below this is the Lower Chalk and deeper down are seams of hearthstone (a white sandstone which, as its name suggests, was sold as a mild abrasive for whitening stone hearths, doorsteps and window sills ^[1]), upper greensand and Gault clay. Some of these deposits have been worked for almost as long as humans have inhabited the area, but the most intensive exploitation of the hill for its minerals began in the 19th century when two neighbouring quarries came to dominate the landscape, leaving huge white scars which could be seen from over twenty miles away. The largest and most impressive of these was set into the hill behind Betchworth Railway Station.

The Dorking Greystone Lime Co. Ltd. was founded at Betchworth in 1865 by brothers Eustace and Charles Townsend Hook of Snodland paperworks, Kent; their chief product was hydrated lime made of the aforementioned grey chalk, used for making cement.

The works were managed in those early days by the engineer William Finlay; in 1866, Finlay installed the first continuous Hoffman kilns in England here and the following year added twelve conical flare kilns in two batteries either side of the quarry floor. The works continued to develop over the next few decades, reflecting changes in demand and new technology: In 1870, the southern flare battery was converted to make 'Selenitic' lime - a hydraulic lime mixed with roughly 5% to 10% calcined gypsum (Plaster of Paris) for use in quick-drying cement. ^[2] In 1887-1897 the southern battery was partly replaced by two pairs of Dietzsch kilns (a continuous upright kiln with multiple 'poke' holes to manually aid the passage of the feedstuff through the firing process) followed by a new crushing and hydrator plant immediately to the southeast. ^[3] Around 1900 a large Smidth kiln (an experimental modification of the Dietzsch kiln comprising two chimneys encased in a single tower) was built to the north of the works yard - for reasons unknown this was was abandoned during construction and was never fired.^[4]

During the 1920s and 1930s the eastern kilns were rebuilt as continuous-burning 'Brockham-patent' kilns, devised in 1899 by Alfred Bishop at the neighbouring Brockham Lime and Hearthstone Co. ^[5]

As well as grey lime for building, the works produced white lime for gas purification and sewage treatment.^[3a] Also, until 1945, lump hearthstone was quarried underground, the main entrance to the mine being behind the eastern kiln battery. After this, the tunnels were sealed and only surface seams were quarried until 1950 when working ceased altogether^[6].