China clay mining has shaped the landscape, lives of people and economy of mid-Cornwall for over 250 years. It is Cornwall’s largest mining industry.

A fully Accredited Museum, we are based within two Victorian china clay works, now a Scheduled Ancient Monument. We tell the story of this fascinating industry and the people who worked and lived in the shadows of Cornwall’s iconic ‘white pyramids’.

A visit might include: wandering around our interactive Discovery Centre, exploring historic trails, woodland walks in grounds teeming with wildlife, and spectacular views of a modern working clay pit.

Our collections include working waterwheels, tools and machinery, vintage lorries and an extensive archive.

China clay mining in Cornwall

The Cornish china clay industry is generally less well known than the tin and copper mining industries, which are often perceived as the iconic industries in Cornwall. However, they pale into insignificance when compared with the china clay industry, which has produced some 170 million tons of china clay from deposits across the Duchy over 250 years.

Approximately 70% of this output has been exported, which is why the industry has been recognised as an important contributor to the national economy and to the earning of foreign currency.

China clay heritage - an industry of national importance

As the traditional tin and copper mining industries in Cornwall started to decline in the late 19th century, the china clay industry grew and far outstripped those industries in size, economic contribution, mining technology and research into micro-mineralogy. The value of china clay sold to date is more than double the value of tin and copper sold from Cornwall, estimated at around £14 billion. 

William Cookworthy discovered the potential of china clay as the ‘secret’ ingredient in porcelain, in 1746. A Quaker apothecary from Plymouth, he patented his formula for hard-paste porcelain in 1768, before opening a pottery in Plymouth which later moved to Bristol.

This discovery was a springboard for an industry which has seen the scientific and technological innovations from Cornwall spread across the world. China clay has been exported across the UK and the globe to be used in a huge range of products – from everyday paper and ceramics to components in spacecraft and pharmaceuticals.

The company English China Clays Ltd. (now part of Imerys Minerals Ltd.) was one of the UK’s top 100 companies and leading exporters in the 1980s and the industry was a driver of the Cornish economy for 100 years.

Our unique site

We are located within two former Victorian clay works, one of which is preserved in its working state and is the only example of its kind which is open to the public.

The site marks a period of the industry’s history, spanning from the 1820s through to the 1960s, when the industry was labour intensive and physically taxing. This is in stark contrast to the modern industry which is largely mechanised. 

We have a unique collection of working mining machinery and much of it is designated as a Scheduled Ancient Monument. As the remnants of the past are gradually eroded, Wheal Martyn is the focal point for celebrating this rich heritage and ensuring it remains alive for future generations.

Find out more about our collection and archive.

Find out more about our built heritage.

A brief history

The clay works began at Wheal Martyn in the 1820s and were started by Elias Martyn on the Carthew Estate. Elias became one of the major clay producers in Cornwall and by 1869 he was producing 2,000 tons of clay a year at Wheal Martyn. After his death in 1872, the family kept the land but leased the works to other operators and the site continued to operate until 1969.

The museum was established at Wheal Martyn in 1975 by English China Clays Ltd., the producers of china clay at the time. The adjacent Wheal Martyn clay pit continues to operate today under the global mining company, Imerys Minerals Ltd.

China clay in your everyday

China clay (kaolin) actually plays a part in just about everybody’s day-to-day life.

It is formed as a result of the decomposition of some of the feldspar in granite. Once refined, a white powder is formed which is used as an ingredient in all sorts of familiar products including:

• Ceramics – such as porcelain
• Paper – as a glossy coating or filing
• Rubber – for example, tyres
• Paint
• Pharmaceuticals – such as paracetamol
• Cosmetics – used by brands such as Lush and L’Oréal
• Toothpaste
• Aircraft components

World Heritage Site Area Centre

Wheal Martyn is an Area Centre for the Cornwall and West Devon Mining Landscape World Heritage Site, known locally as the Cornish Mining World Heritage Site. It has an important role to play, particularly through its links with the nearby Luxulyan Valley and the former mineral port at Charlestown, both of which are within the World Heritage Site and have strong connections with the china clay industry. Find out more about the World Heritage Site here.