A different kind of industrial landscape
Travelers approaching St Austell from certain directions see something that does not look like the rest of Cornwall: broad, pale, flat-topped hills rising above farmland, some grassed over and some bare. These are the waste tips of the china clay industry. The area around them is often called clay country, and its character is closer to that of an open quarrying district than to the narrow valleys and engine houses of the old mining areas.
What china clay is
China clay is another name for kaolin, a fine, white, soft material formed when the feldspar in granite breaks down over a very long time. In parts of Cornwall the granite was weathered deeply enough that the clay is found within the rock, mixed with quartz sand and mica. That is why the main clay workings sit on granite uplands rather than on the ore-bearing rocks that attracted miners.
The material has long been valued because it is white, fine and chemically stable. Its best-known early use was in porcelain, and the work of William Cookworthy, a Plymouth chemist who identified Cornish clay and stone suitable for making porcelain in the eighteenth century, is often cited in the story of the industry’s beginnings. Later, clay was widely used in paper, where it helps give a smooth, bright surface, and it has many other uses in ceramics, paints and other manufactured goods. Exact uses and proportions change over time, so it is safest to describe them in general terms.
How the clay is extracted
The method is quite different from mining ore. In general terms, the process works as follows:
- The clay-bearing ground is exposed in an open pit.
- High-pressure water jets wash the clay out of the rock face, producing a milky slurry.
- The slurry is pumped to a processing area, where coarse sand and mica are separated from the fine clay.
- The fine clay is settled, thickened and dried before being sent for use or export.
Historically, the water and the pits were handled with simpler equipment, and settling took place in series of tanks and drying areas. Specific details vary by period and company, so this summary is deliberately broad.
Where the tips come from
Every tonne of clay that is sold leaves a great deal of other material behind. Two main waste streams explain the shape of the landscape:
- Coarse sand, mostly quartz, which was traditionally carried up on tramways or conveyors and tipped into the cone-shaped or flat-topped heaps that gave the area its distinctive skyline.
- Overburden and rock waste, the soil and weathered rock that had to be removed to reach the clay, which was stacked in separate heaps.
The tallest sand tips were nicknamed the Cornish Alps, a name that is affectionate rather than technical. Over time, some tips have been reshaped or partly removed, since sand and aggregate have uses of their own, and many have been planted or have slowly greened over through natural colonization by heather, gorse and other plants.
Pits, pools and colors
Worked-out pits often fill with water. The result can be strikingly colored, depending on the minerals and the light, which is partly why clay country has attracted photographers and artists. Visitors should treat these places with caution. The edges can be unstable, the water can be very deep and cold, and many pits and tips are on private land that is still being worked.
Some former pits and workings elsewhere in the area have been reused for leisure, planting and other projects, and the region has become a talking point in discussions about how to reuse industrial land. Opinions differ about what the best approach is, and local people have a range of views.
Clay and community
The clay industry employed many people, and it shaped villages, chapels, rail and port links and local identity in its own right. Workers lived close to the pits, and the industry developed its own vocabulary and customs. It also continued to operate after most metal mines had closed, which means clay has often been described as one of the few traditional extractive industries still active in the county. This is a broad statement and it should be read as one that depends on the date and on how activity is measured.
Clay was usually shipped from nearby ports, and some harbors grew in size because of the trade. The railway also carried clay, which tied the industry to the same transport network that later supported railway tourism across the county. The dust, noise and heavy traffic of a working industry were not always welcome to neighbors, and the balance between employment and environmental impact has long been debated.
Seeing the landscape well
Anyone interested in this part of Cornwall can learn a lot by looking at a map or from public viewpoints and footpaths, keeping to marked routes and obeying any warning signs. Active sites are not open to casual exploration, and the same caution that applies to mine site safety applies to old workings here. Because opening arrangements and access change, it is wise to check local guidance before going. As elsewhere, a respectful visit means treating working landscapes as places where people earn a living.
In short, china clay country is a reminder that Cornish geology offered more than metal. The same granite that gave the moors their granite tors also produced a pale, fine material that traveled around the world, and left behind one of the most unusual landscapes in the British Isles.