Wheal Martyn China Clay Museum

Andy Fish

On the last day of last year’s Hampshire Mills Group study trip to Cornwall we visited Wheal Martyn, just two miles from St. Austell, a museum which has become home to the UK’s only china clay mining museum.

The Wheal Martyn Museum site incorporates two former china clay works.  The Gomm Works were leased by the Martyn Brothers from the Mount Edgcumbe Estate in about 1878 and were worked until the 1920s.  The Wheal Martyn china clay works began working much earlier, in the 1820s. 

It was started by Elias Martyn on the Carthew Estate, bought by his father Richard in 1790.  Elias became one of the major clay producers in Cornwall.  By the 1840s he operated 5 pits and by 1869 was producing 2000 tons of clay a year at Wheal Martyn.

In the 1880s John Lovering took on the lease at Wheal Martyn.  The pit worked until the effects of poor trade forced its closure in 1931.  The Dry continued to operate until 1969, working lower grade clay from pits further up the valley.  Wheal Martyn Pit reopened in 1971 and continues to be worked today by Imerys Minerals Ltd.

In 1974 The Wheal Martyn Trust was established as a charity by English China Clays, who set up a museum in 26 acres of grounds alongside the St Austell river.  As well as the historic buildings, the museum owns and looks after a large collection of items associated with the china clay industry.  In 2001 China Clay History Society, which now has over 240 members was set up to manage this large archive.

In late 2015 Wheal Martyn was awarded development funding from the Heritage Lottery Fund, along with funding from Arts Council England, and Imerys Minerals Ltd, to develop the 'Clay Works! Project’.  This project will preserve the disused Mica Dry building and open it to the public for the first time.  It will create a new exhibition and learning space and will connect different levels of the museum whilst providing access to an outdoor learning area in the former settling tanks.

As with many china clay works, Wheal Martyn was built on a hillside to help the clay slurry move around by gravity.  However, some settling pits here were located above the mica drags and needed to be filled with clay slurry by a pump.  In about 1902 John Lovering, an inventive clay producer who introduced many new ideas to Wheal Martyn, built the 18ft overshot waterwheel and slurry pump to fill the pits.  The clay slurry was lifted by a piston fitted with a valve which worked inside a cast iron pipe, lifting about 26 gallons (120 litres) per stroke.  The slurry pump, which is operated by the waterwheel, via an extensive set of flat rods, is the only surviving pump of its type out of an estimated 200 which were once in existence throughout the clay industry in Cornwall.

Ongoing work at the museum will include refurbishment of this waterwheel (below left) at an estimated cost of £32,000, with the major cost being the European oak.  (Editor:  I assume the oak is for the overhead launder and the balance box for the flat rod system, as the wheel is clearly metal.)

Apart from a spectacular view (below right) down into the Wheal Martyn clay pit, which is still in operation, the site includes a preserved Victorian clay works, and woodland walks.