Cornish holidays: beauty, wildness, mystery.  Crashing seas, coves, beaches, wind-swept uplands, lighthouses, fishing villages, smugglers, sea shanties, tales of adventure, romantic ruins and mineral extraction.  Yep, it’s all part of that Cornish allure.  

Well, precious little of course, but when industry becomes heritage, perception changes.   Those “hundreds of roofless engine houses across the landscape” (Peter Stanier again) are an alluring hint of bygone times.  But, as we noted in the ‘Tinners’ blog, tin mining not only left a landscape of iconic industrial archaeology, it also left very little obvious waste. 

Not so Cornwall’s other “massively important” (more Stanier) mineral industry – China Clay.  China clay extraction and processing changed the rural landscape from green to an often startling white, either as holes in the ground, or as conical heaps (sky tips) of waste materials.  It had an enormous visual impact over a huge area.  Characteristic of many areas of Cornwall, and yes iconic, but I suspect few find it romantic.

The internal environment created by China Clay processing could be very different, however, and the lives of the workers, though tough and physically exacting was probably very different to the life of a tin miner.

In Terroir’s school days, China Clay was always mentioned in secondary school geography lessons, although I have no memory of being told of its use in ceramics, merely as an additive to fabrics and toothpaste.  I don’t think historical geography was well regarded then.  I do remember references to ‘rotting granite’ which we thought was highly amusing. So a very quick summary of the history of china clay may be appropriate.   

The quantities required, and the softness of the raw material, meant that a flow of water was the simplest way of removing the kaolinised granite.  Gravity fed water flows were soon replaced by hand held hoses, which later developed into the high pressure, serpent like, ‘Monitors’.

The clay slurry had then to be pumped from the pit to surface level.  Initially water wheels provided the energy until replaced by steam powered pumps. 

The slurry of clay, sand and mica, went to the sand ‘drags’, a system of gently sloping channels, which allowed the sand to settle out - and this spoil was discharged to the river.    

Next the mica drags performed a similar job for the smaller mica particles, which were also discharged to the river, often mixed with a smidgeon of clay slurry; the rivers ran white as a result. 

At Wheal Martyn, the pure clay slurry then entered the Blueing House (still with us?), was sieved through a wire mesh to remove leaves or other materials which may have dropped in, and a blue dye could be added, to hide any discolouration which would have reduced the value of the clay.

Next, the slurry flowed into the settling pits and clear water was drained off as the clay dropped to the bottom over a number of days.  Once the clay was the consistency of single cream, the slurry was run into the settling tanks and the process repeated until the slurry was as thick as clotted cream.  This could be a slow process.

Finally, the ‘cream’ flowed or was trucked into the pan kiln. This was lined with porous pan tiles which allowed heat from flues beneath the floor to rise upward and dry out the clay. At least the pan tiles at Wheal Martyn were made from waste clay and sand, but we doubt this made much of a difference to the volume of waste material to be dicarded.

The pan kiln at Wheal Martyn is remarkably well preserved and imaginatively interpreted. It reminded Terroir of hand made brick works, where the craft and skills of the individual brick makers belies the external mayhem of clay winning outside. Similarly at Wheal Martyn, the pre-mechanised, human scale of the clay processing presented craft skills and human endeavour which stand at odds with the large scale business of hauling china clay out of the ground.

The human element was largely made up of men and boys, although women were employed to scrape clean the bottom and sides of air dried clay blocks.

Images above: China Clay History Society

The techniques shown above did not last, and increased mechanisation did nothing to reduce the quantity and quality of waste, stacked around the clay pits.

Images above: China Clay History Society

The industry continues today, of course.  Many Victorian companies amalgamated into larger units, but around 70 producers still existed prior to WWI.    Three of the largest - West of England and Great Beam Clay Co, Martin Brothers, and the North Cornwall China Clay Co – were amalgamated in 1919 to become English China Clays and, through further mergers and reorganisations the company survived the lean times before and after WWII.  In 1999, the core of the company was purchase by Imetal, now known as Imerys.  It’s signs are everywhere throughout the Cornish China clay territories.

The most famous restoration scheme – The Eden Project – opened in 2001: “We bought an exhausted, steep-sided clay pit 60 metres deep, with no soil, 15 metres below the water table, and essentially gave it life.”  (https://www.edenproject.com/mission/our-origins). The projects mission is to “create a movement that builds relationships between people and the natural world to demonstrate the power of working together for the benefit of all living things”. It is a significant player in Cornish Tourism.

Schemes in other areas have been less ambitious but our overwhelming experience of the 2022 Cornish China Clay landscape is of gentler land forms, of colour schemes now in a palette of browns, greens and yellows, of native species, grassy areas and new woodlands.  Of ‘come in’, rather than ‘keep out’.  It’s not perfect.  But words such as ‘healing’ and ‘biodiversity’ come to mind.  The iconic Cornish Alps have largely gone but a symbolic sky tip or two remain, although these, too, are turning from grey and white, to brown and green.

Is it romantic yet?  Terroir thinks not.  But we are hopeful that, one day, derelict 21st century wind turbines will be considered romantic - that is if we and the planet make it that far.