The History of China Clay in Cornwall

In the late seventeenth century, traders from the far east began to bring home beautiful cups and plates made out of exquisite porcelain. To a continent that was used to pottery and stone wear, these pieces were treasures to be desired. The items were as thin and light as bones, they rang when you struck them and the light shone through them. And yet they were strong enough the eat and drink from.

The British couldn’t get enough of these expensive imports and acquiring them was the ultimate display of wealth and privilege. William Cookworthy was aware that if he could only find kaolin in the UK he would be sitting on a goldmine. He searched the country and in 1746 he finally found a deposit of a similar standard to the Chinese kaolin, here in Cornwall. Earning it the nickname of china clay.

The deposit required work to extract it from the degraded granite.  Using water he would separate the decomposing granite and the soft talc like material. Once refined, this material could be worked as kaolin and was quickly taken up and used in the British manufacturing processes. If the Chinese product was finer, this was disregarded, and the Cornish market exploded.  A deposit north of St Austell was revealed to be the largest in the world and a global industry began to rapidly develop.

The material didn’t require deep mining like tin or copper, and was retrieved using open cast mining.  It was then blasted with water cannons, to separate the soft clay from the decomposing granite. The water turned white and ran off into the rivers, and as they ran down into St Austell Bay, the whole sea would turn white. Even in the 1970s, locals remember swimming in milky white water.  For each tonne of clay extracted, there was five tonnes of mica waste. When the two materials were separated, the slag was taken and dumped back on the land, in long hills or in large conical structures. These large white hills were soon referred to as the Cornish Alps or Pyramids and rapidly changed the local skyline.  Finally the good wet clay was recovered and laid out in massive long low buildings, known as dries.  With a chimney at each end, heat was run along the base and the clay above would slowly dried out. Women, known as bal maidens, would shape and turn the mixture until it resembled dry blocks, that could be cut and easily transported up country and overseas to the waiting mills. This industry far out performed fishing or farming and there wasn’t a single family that wasn’t in some way impacted by the new industry.

Leats (small canals) were laid out across the land to provide water directly to the source, and water wheels were built to power the engineering processes. The entire land in this area was covered in dries, villages grew up, simply to extract the clay.   Initially these dries were built right near the extraction points, but gradually as the railways were built, the wet sludge was transported to the docks at Charlestown, Pentewan and eventually the industry was consolidated at the large docks at Par. The expansion of the industrial industries in mid-Cornwall was all to further the china clay industry and over the centuries, vast fortunes were made. Over 250 years, 170 million tonnes of china clay was produced. 70% of this production was exported overseas, making Cornwall the pre-eminent global source of china clay.

China clay was in great demand and not just because of its use in the porcelain industry but because of its other properties.   Any pill you have ever swallowed is coated in china clay to help it go down better, every glossy magazine or brochure is coated in it, to give it that smooth finish.  It is used in toothpaste, make up, light bulbs, in the rubber process,  in medicine, in the paper industry, not to mention the porcelain industry, and many more uses besides. The chances are, that every single day, you come into contact with china clay in one shape or another.

Looking about you today every strange hill you see, will be a slag heap. The largest pyramid towering over St Austell is now only vaguely white but it must have been an incredible sight before nature began to reclaim it. Some of the heaps have been flattened and terraformed providing excellent walks and bike rides, and if you look at the floor you will see, that rather than soil, the ground is made up of a gritty mica residue. Strange building are hidden under trees and ivy, overs can be explored in safety. Some areas of the terraformed lands still seem reminiscent of a foreign planet, others are more established, and the flora and fauna has established itself and smoothed over the harsh scars on the landscape. The world famous Eden Project is built in a clay pit, showing the ingenuity of mankind to reclaim the land. Across the countryside are large lakes where the miners dug down to extract the raw material. As well as the lakes are large shallow pans of water, full of strange glowing green water, each pan a slightly different shade, covering many acres.

Nowhere in mid-Cornwall is untouched.  Although the industry is still active here, it has declined with the discovery of a massive deposit in Brazil. The industry has moved to a fresher source, that is easier to extract with cheaper labour costs.  It is hard to look around at some of the towns and villages today and appreciate that these were once the white hot hubs of industry at the top of a global market. A time when Cornwall led the world.