Purbeck Ball Clay

Last updated May 03, 2019

Purbeck Ball Clay is a concentration of ball clay found on the Isle of Purbeck in the English county of Dorset.

Ball clays are kaolinitic sedimentary clays that commonly consist of 20–80% kaolinite, 10–25% mica, 6–65% quartz. Localized seams in the same deposit have variations in composition, including the quantity of the major minerals, accessory minerals and carbonaceous materials such as lignite. They are fine-grained and plastic in nature, and, unlike most earthenware clays, produce a fine quality white-coloured pottery body when fired, which is the key to their popularity with potters.

The Isle of Purbeck is a peninsula in Dorset, England. It is bordered by water on three sides: the English Channel to the south and east, where steep cliffs fall to the sea; and by the marshy lands of the River Frome and Poole Harbour to the north. Its western boundary is less well defined, with some medieval sources placing it at Flower's Barrow above Worbarrow Bay. According to writer and broadcaster Ralph Wightman, Purbeck "is only an island if you accept the barren heaths between Arish Mell and Wareham as cutting off this corner of Dorset as effectively as the sea." The most southerly point is St Alban's Head. Its coastline is suffering from erosion.

England is a country that is part of the United Kingdom. It shares land borders with Wales to the west and Scotland to the north-northwest. The Irish Sea lies west of England and the Celtic Sea lies to the southwest. England is separated from continental Europe by the North Sea to the east and the English Channel to the south. The country covers five-eighths of the island of Great Britain, which lies in the North Atlantic, and includes over 100 smaller islands, such as the Isles of Scilly and the Isle of Wight.

Geology

The main concentration of ball clay in Dorset is to the north of the Purbeck Hills centred on Norden. Ball clays are sedimentary in origin. Approximately 45 million years ago (in the Lutetian stage of the Eocene epoch) the climate was tropical and an ancient River Solent washed kaolinite (formed from decomposed granite) from its parent rock on Dartmoor. As the streams flowed from upland areas they mixed with other clay minerals, sands, gravels, and vegetation before settling in low-lying basins to form overlaying seams of ball clay. Ball clays usually contain three dominant minerals: from 20–80% kaolinite, 10–25% mica, and 6–65% quartz. In addition, there are other 'accessory' minerals and some carbonaceous material (derived from ancient plants) present.

The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between 47.8 and41.2 Ma. The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Middle Eocene subepoch.

The Eocene Epoch, lasting from 56 to 33.9 million years ago, is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope ¹³C in the atmosphere was exceptionally low in comparison with the more common isotope ¹²C. The end is set at a major extinction event called the Grande Coupure or the Eocene–Oligocene extinction event, which may be related to the impact of one or more large bolides in Siberia and in what is now Chesapeake Bay. As with other geologic periods, the strata that define the start and end of the epoch are well identified, though their exact dates are slightly uncertain.

Kaolinite is a clay mineral, part of the group of industrial minerals, with the chemical composition Al₂Si₂O₅(OH)₄. It is a layered silicate mineral, with one tetrahedral sheet of silica (SiO
4) linked through oxygen atoms to one octahedral sheet of alumina (AlO
6) octahedra. Rocks that are rich in kaolinite are known as kaolin or china clay.

Exploitation

Purbeck Ball Clay has been used for thousands of years, but large scale commercial extraction began in the middle of the 18th century and continues today. The principal workings were in the area between Corfe Castle and Wareham. Originally the clay was taken by pack horse to wharves on the River Frome and the south side of Poole Harbour.^[1]

Corfe Castle is a village and civil parish in the English county of Dorset. It is the site of a ruined castle of the same name. The village and castle stand over a gap in the Purbeck Hills on the route between Wareham and Swanage. The village lies in the gap below the castle, and is some eight kilometres south-east of Wareham, and the same distance west of Swanage. Both the current main A351 road from Lytchett Minster to Swanage and the Swanage Railway thread their way through the gap and the village.

Wareham is a historic market town and, under the name Wareham Town, a civil parish, in the English county of Dorset. The town is situated on the River Frome eight miles (13 km) southwest of Poole.

A wharf, quay, staith or staithe is a structure on the shore of a harbor or on the bank of a river or canal where ships may dock to load and unload cargo or passengers. Such a structure includes one or more berths, and may also include piers, warehouses, or other facilities necessary for handling the ships. Wharfs are often considered to be a series of docks in which boats are stationed.

Large quantities were ordered by Josiah Wedgwood from 1771 and this led to the construction of Dorset's first railway in 1806. This was the Middlebere Plateway owned by B.Fayle & Co (Directors were Alexander Jaffray, Benjamin Fayle, Richard Jaffray and Richard Chambers). The Plateway connected clay workings in the Corfe Castle area, to a wharf on Middlebere Creek in Poole Harbour. Other similar tramways followed, including the Furzebrook Railway (c.1840), the Newton Tramway (1854), and Fayle's Tramway (1907). With the coming of the London and South Western Railway line from Wareham to Swanage in 1885, much of the ball clay was dispatched by rail.^[1]

Josiah Wedgwood was an English potter and entrepreneur. He founded the Wedgwood company. He is credited with the industrialisation of the manufacture of pottery; "it was by intensifying the division of labour that Wedgwood brought about the reduction of cost which enabled his pottery to find markets in all parts of Britain, and also of Europe and America." The renewed classical enthusiasms of the late 1760s and early 1770s were of major importance to his sales promotion. His expensive goods were in much demand from the nobility, while he used emulation effects to market cheaper sets to the rest of society. Every new invention that Wedgwood produced – green glaze, creamware, black basalt and jasper – was quickly copied. Having once achieved perfection in production, he achieved perfection in sales and distribution. His showrooms in London gave the public the chance to see his complete range of tableware.

The Middlebere Plateway, or Middlebere Tramway, was a horse-drawn plateway on the Isle of Purbeck in the English county of Dorset. One of the first railways in southern England and the first in Dorset, the plateway was built by a wealthy Irish Merchant based in London Benjamin Fayle, to take Purbeck Ball Clay from his pits near Corfe Castle to a wharf on Middlebere Creek in Poole Harbour, a distance of some 3.5 miles (5.6 km).

The Furzebrook Railway, also known as the Pike Brothers' Tramway, was a narrow gauge industrial railway on the Isle of Purbeck in the English county of Dorset. It was built by the Pike Brothers, to take Purbeck Ball Clay from their clay pits near Furzebrook and West Creech to a wharf at Ridge on the River Frome.

Approximately 80% of the ball clay extracted has been exported. The ball clay is processed today at the Furzebrook plant of Imerys. It is said that a third of all fine pottery ever produced in England contains Purbeck Ball Clay.^{[ citation needed ]}

Imerys S.A. is a French multinational company which specialises in the production and processing of industrial minerals. It is headquartered in Paris and is a constituent of the CAC Mid 60 index.

Usage

Ball clays are used in making everyday articles including:

wall and floor tiles, wash basins, toilet bowls, plates, cups and saucers, linoleum, acoustic ceiling tiles, insulated electrical cables, pale coloured bricks, and clay drainage pipes
windscreen wipers^{[ citation needed ]}, spark plugs, and engine mountings
hoses and fertilisers
pharmaceutical and polymers and many others
kiln furniture

Museum

The Purbeck Mineral and Mining Museum displays an exhibition about ball clays, mining and the associated narrow gauge railways.

Related Research Articles

The River Frome is a river in Dorset in the south of England. At 30 miles (48 km) long it is the major chalkstream in southwest England. It is navigable upstream from Poole Harbour as far as the town of Wareham.

Purbeck was a local government district in Dorset, England. The district was named after the Isle of Purbeck, a peninsula that forms a large proportion of the district's area. However it extended significantly further north and west than the traditional boundary of the Isle of Purbeck along the River Frome. The district council was based in the town of Wareham, which is itself north of the River Frome.

Church Knowle is a village and civil parish on the Isle of Purbeck in the county of Dorset in the south of England.

The Swanage Railway is a railway branch line from near Wareham, Dorset to Swanage, Dorset, England, opened in 1885 and now operated as a heritage railway.

Wytch Farm is an oil field and processing facility in the Purbeck district of Dorset, England. It is the largest onshore oil field in western Europe. The facility, taken over by Perenco in 2011, was previously operated by BP. It is located in a coniferous forest on Wytch Heath on the southern shore of Poole Harbour, two miles (3.2 km) north of Corfe Castle. Oil and natural gas (methane) are both exported by pipeline; liquefied petroleum gas is exported by road tanker.

Mid Dorset and North Poole (UK Parliament constituency) Parliamentary constituency in the United Kingdom

Mid Dorset and North Poole is a constituency represented in the House of Commons of the UK Parliament since 2015 by Michael Tomlinson, a Conservative.

Swanage railway station is a railway station located in Swanage, on the Isle of Purbeck in the English county of Dorset. Originally the terminus of a London and South Western Railway (L&SWR) branch line from Wareham, the line and station were closed by British Rail in 1972. It has since reopened as a station on the Swanage Railway, a heritage railway that currently runs from Norden station just north of Corfe Castle to Swanage station. It now also runs to Wareham on certain services, but not on regular services due to signalling problems.

Corfe Castle railway station is a railway station located in the village of Corfe Castle, in the English county of Dorset.

Norden railway station is a railway station located one mile to the north of the village of Corfe Castle, on the Isle of Purbeck in the English county of Dorset. It is situated on the Swanage Railway, a heritage railway that operates over the former London and South Western Railway line from Wareham to Swanage. Norden is the northern terminus of the railway's steam service from Swanage, and an intermediate stop on the railway's diesel hauled service that connects Swanage with the national rail network at Wareham station.

Ridge is a village in the English county of Dorset. It is situated on the south bank of the River Frome, about half a mile due south east of the town of Wareham.

Blue Pool is a flooded, disused clay pit where Purbeck ball clay was once extracted. It is now a lake within the Furzebrook Estate, a 25-acre (10 ha) park of heath woodland and gorse near Furzebrook on the Isle of Purbeck, in the county of Dorset, southern England.

Furzebrook is a small village on the Isle of Purbeck, in the county of Dorset in the south of England. It is about 2 miles (3.2 km) south of Wareham and 2 miles (3.2 km) northwest of Corfe Castle, and is in the civil parish of Church Knowle.

Dorset is a county located in the middle of the south coast of England. It lies between the latitudes 50.512°N and 51.081°N and the longitudes 1.682°W and 2.958°W, and occupies an area of 2,653 km². It spans 90 kilometres (56 mi) from east to west and 63 kilometres (39 mi) from north to south.

Hartland Moor is a Site of Special Scientific Interest (SSSI) on the south side of Poole Harbour near the town of Wareham in Dorset, England. It consists of lowland heathland.

The Purbeck Mineral and Mining Museum exists to preserve and interpret the historic extractive industries in ball clay mining in the Isle of Purbeck. The museum is located adjacent to Norden station on the Swanage Railway and is open from the end of March to the end of September on weekends, some weekdays and Bank Holidays.

References

1 2 Kidner, R.W. (2000). The Railways of Purbeck (Third ed.). The Oakwood Press. ISBN 0-85361-557-8.

External links

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[trop-1] 1 2 Kidner, R.W. (2000). The Railways of Purbeck (Third ed.). The Oakwood Press. ISBN 0-85361-557-8.