2-860-910 - Reproduced by permission of English Heritage/Heritage Images

Bloomdale China Clay and Stone Works, St Stephen-in-Brannel, Cornwall, 1919-1936. Bloomdale China Clay and Stone Works, St. Stephen-in-Brannel, Cornwall, 1919 - 1936. A view of the engine house at Bloomdale China Clay and Stone Works, showing the aqueduct used to carry the clay stream to the trenches known as 'Micas'. This photograph forms part of a set within the album documenting the china clay industry of Cornwall, particularly focusing on the area around St Austell. China clay - also called kaolin - was used to make porcelain. The china clay industry was one of the main extractive industries in Cornwall. The images are accompanied by handwritten notes and descriptions of the processes involved in the production of china clay. Together they form a fascinating insight into the industry in the early-mid 20th century. The image numbers that form this set are ALB93/05/115 - ALB93/05/150. The caption by this image reads: "On reaching the surface the stream is carried by means of an aquaduct to a series of trenches known as the 'Micas'. These trenches are narrow and run into narrower channels. The stream is only allowed to pass very slowly through the 'micas', which are so constructed as to have only a 1/2 inch run on every 12 feet in length. This enables the mica to sink to the bottom from which it is released by traps. It then passes into the mica settling pit. Each row of traps is worked by a hand lever from the side of the pit".