What is China clay mining? Near £18m investment announced for Cornwall

ITV News

10-05-2025

Aerial footage of Cornish Clay County and diggers at the new site (credit: Cornish Lithium, Imerys).
A mineral supplier has announced it will invest nearly £18million in a new china clay plant in Cornwall, which will reduce its electricity use in the Duchy by 10%.
Imerys which has been extracting china clay (kaolin) in the county for more than 25 years, will now build a dry mining plant near Roche - where clay will be extracted and processed without significant water usage.
It's hoped the facility will be up and running by 2026.
What is china clay and how is it mined?
China clay is a material known as kaolin, which was first used in China more than 10 thousand years ago to make fine white porcelain. Some of this eventually made its way to Europe.
Noticing a gap in the market, a Plymouth apothecary began to research the porcelain-making process and spent several years searching for a material that resembled kaolin. In 1745 he found it, at Tregonning Hill in Cornwall.
By the mid 19th century 65,000 tonnes of china clay were being mined from the St Austell area every year by 7,000 workers.
Kaolin is traditionally extracted from mines using a hydraulic mining method. This is a wet process where high pressure water washes the clay from the granite - forming a slurry to transport it via pipes to a drying site.
A new dry mining technique will be used at Imerys' new site, which expends less water and electricity.
This, in short, involves removing topsoil and rock, extracting the clay, and processing it to separate it from other materials.
Kaolin is exported around the world from Cornwall for use in ceramics, paints, coatings, plastics and life sciences.
More than £2million of funding for the new development in Cornwall is government-granted, through the UK Shared Prosperity Fund.
What will happen to the existing plant?
The relocation of the new facility will also mean that the existing plant is decommissioned, creating access to additional kaolin reserves and extending the life of kaolin operations in Cornwall.
Mark Hewson, who leads Imerys in the UK said: "We have been active here for over 25 years, with China clay, or kaolin as it's also known - being mined here for nearly 300 years.
"Through direct and indirect employment, we support around 3,500 jobs and in addition spend more than £40 million every year in the local economy.
"This investment - which allows the significant update of our facilities - will help us to shore up those jobs and maintain that economic support for many years to come.
'Lithium mining here in the South West is strategically important for the UK as we move forward to net zero, but in parallel to that - kaolin mining has been and will continue to be a mainstay of the Cornish economy.
'This investment is essential as we develop and improve our existing mining infrastructure - as this will facilitate the set up of our lithium project - which is located in an old China clay pit.
"The strength of our project is our ability to use our existing China clay assets to minimise the impact on the local area.'