Previously unknown to the English potters at the beginning of the 18th century, china clay and china stone were found in Cornwall. Once the clay was ready for marketing, it then had to be shipped out of the county.
The roads were inadequate and the railways non-existent until the latter half of the 19th century. With the construction of the harbour by Charles Rashleigh, Charlestown became the only shipping outlet for the St Austell area. In 1876, Charlestown shipped over 34,000 tons of clay and china stone to both foreign and domestic ports.
Also in 1813, 3792 tons of copper were shipped in the space of 4 months on 49 separate ships from the Crinnis mine alone.