Purbeck Ball Clay
Purbeck Ball Clay is a clay deposit found on the Isle of Purbeck in the county of Dorset in the south of England . The highest concentration of Purbeck Ball Clay is in the north of the Purbeck Hills around the village of Norden near Furzebrook , between Corfe Castle and Wareham .
What is Ball Clay?
Clay is a naturally occurring mineral that is made up of fine-grained minerals and can absorb different amounts of water. If the water content is appropriate, clay is plastic; clay hardens when it is dried or fired. Ball clays are of sedimentary origin. Ball clay is an extremely rare mineral due to the combination of geological factors necessary for formation and conservation.
Ball clay is found only in very few places around the world. Ball Clay is mined in parts of the east of the United States as well as at two mines in Devon (Bovey Basin in the south, Petrockstowe Basin in the north) and in the Wareham Basin on the Isle of Purbeck.
Purbeck Ball Clay is a fine-grained, very plastic sedimentary clay that can be burned to a very light or almost white color.
The name Ball Clay goes back to the early methods of mining. Special hand tools were used to cut the clay into roughly 25 to 30 centimeters thick cubes. Since the corners were often knocked off by handling and storage, these cubes were rounded and bumped into a "ball" -like shape. Ball clay is sometimes referred to as plastic clay.
Emergence
About 45 million years ago the climate was tropical. In what was then the old river " Solent ", kaolinite (formed from crumbled granite ) formed from the bedrock on Dartmoor . In the streams, kaolinites have mixed with other clay minerals, sand, gravel and vegetation. The minerals were deposited in the deep basins.
Ball clays usually contain three dominant minerals: 20 to 80% kaolinite, 10 to 25% mica, and 6 to 65% quartz . It also contains other minerals and carbonaceous chondrite . The differences in the mineral compositions, as well as the different masses of the clay particles, result in different characteristics in the individual deposited layers.
Extraction
Before 1800
It is generally accepted that Purbeck Ball Clay has been used since Roman times, perhaps even since the Early Bronze Age. There is evidence that there was a Roman pottery near Norden in the third century.
It was with the introduction of tobacco to England in the 16th century by Sir Walter Raleigh that the need arose to track down a suitable clay for making smoking pipes. This led to the beginning of the modern Purbeck Ball Clay trade. Large-scale commercial mining began in the mid-18th century. The main work was carried out in the area south of Wareham, in the Wareham Basin.
Originally the Purbeck Ball Clay was transported by draft horses to the docks and loading bays on the River Frome or on the south side of Poole Harbor.
In 1771 Josiah Wedgwood signed a contract with Thomas Hyde in Arne for the delivery of 1,400 tons of Purbeck Ball Clay for the manufacture of thin-walled ceramics. Wedgwood had previously tried unsuccessfully to get clay from other suppliers of clay, including asking his friend, Joseph Banks , to get a specific clay from Botany Bay , Australia . Wedgwood came to the conclusion that the "blue Bagshot clay" found around Wareham was best for this purpose. Wedgwood used the "Purbeck Blue Ball Clay" for its world famous Queen's merchandise, which made him a very wealthy man.
The 1796 census shows that 55 out of 96 men involved in the local industry at Corfe Castle were engaged in clay cutting.
The whole area around Arne developed through the extraction and export of Purbeck Ball Clay. Much of it was transported across the River Frome, but some by rail on narrow-gauge railways to Poole Harbor. In 1813 the Transport on Purbeck Ball Clay was exempt from all pool port taxes.
The railroad
Wedgwood's contract later resulted in the construction of the first railroad in Dorset in 1806. This was the Middlebere Plateway. A plateway is an early type of railroad, or tram, or horse-drawn tram, a means of transport running on cast iron rails and drawn by horses as draft animals.
This plateway connected the clay works of London merchant Benjamin Fayle at Corfe Castle to a quay on Middlebere Creek in Poole Harbor. Other, similar trams followed, including the Furzebrook Railway (1830), the Newton tram (circa 1860), and the Fayle tram (1907).
The brothers William Joseph Pike and John William Pike were Purbeck Ball Clay dealers. They built a railway line from Ridge to Furzebrook around 1840 . They later extended this to Creech. In 1866 they brought the first steam locomotive to the Isle of Purbeck.
The Ball Clay dealers, in collaboration with John Mowlem, proposed a Swanage Railway System in 1874. However, this could not be achieved because the economic recession started at that time. However, when the Swanage Railway was finally built in 1885, special sidings were built for the transport of the Ball Clay in Furzebrook, and sidings in Swanage for the Purbeck stone . After the London and South Western Railway from Wareham to Swanage was built in 1885, the Purbeck Ball Clay was shipped by rail. Ball clay was the most valuable cargo on the Swanage Railway during the first half of the 20th century.
Purbeck Ball Clay is still extracted from several deposits on the Isle of Purbeck and pottery clay is processed in Furzebrook. The sound is now transported with trucks or standard gauge trains. Currently, pottery clay is the UK's second most important mineral export after oil exports.
Forms of use
Purbeck Ball Clay is used in the manufacture of everyday items:
- Wall and floor tiles, sinks, toilet bowls, plates, cups and saucers, linoleum, tiles, acoustic ceiling cladding, insulation for electrical cables, pale-colored bricks and drainage pipes.
- Windshield wipers, spark plugs and engine block gaskets.
- Hoses and fertilizers.
museum
The Purbeck Mineral and Mining Museum has an exhibition on the subjects of Purbeck Ball Clay, clay mining and narrow-gauge railways on the Isle of Purbeck .
Individual evidence
- ^ RW Kidner: The Railways of Purbeck , Third Edition. Edition, The Oakwood Press, 2000, ISBN 0-85361-557-8 .
- ↑ http://www.pmmmg.org/Pike ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. railway.htm The Purbeck Mineral and Mining Museum, the Pike Railway
