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Fuller’s earth
Fuller’s earth is a sedimentary clay that contains a high proportion of clay minerals of the smectite group, the most important of
which is montmorillonite. Smectite clay minerals exhibit a unique combination of properties, including a high ‘cation-exchange
capacity’. This means that calcium-smectite, the principal constituent of British fuller’s earths, can be readily converted to sodiumsmectite
by a simple process involving the addition of small amounts of sodium carbonate. It is commercial practice in Britain to
refer to this sodium-exchanged clay as bentonite, which exhibits markedly different properties to calcium-smectite.
UK sales of fuller’s earth, most of which are in the sodium-exchanged form (bentonite), were 26 000 dry tonnes in 2004 and
6200 dry tonnes in 2005 when production finally ceased, bringing to an end this long established minerals industry. UK imports
of bentonite in 2005 were 155 832 tonnes valued at £10.6 million.
Fuller’s earth was formerly produced by two companies in the UK: Rockwood Absorbents (Baulking) Ltd and Steetley Bentonite
and Absorbents Ltd. Rockwood Absorbents (Baulking) Ltd produces fuller’s earth at Baulking in Oxfordshire. The clay was processed
on site, mainly for conversion into bentonite for use as a filler and fibre retention aid in papermaking and as a bonding
agent for foundry sand. The original Baulking quarry was exhausted in summer 2002 and is now restored. Until the closure of
the Baulking plant in October 2005, sales were based on stockpiles of crude fuller’s earth, both from Baulking and the company’s
former operation at Clophill in Bedfordshire. Remaining permitted reserves of fuller’s earth in the Baulking area are confined to a
small satellite deposit at Moor Mill Farm, about 2 km from the plant at Baulking. The deposit contains reserves of some 300 000
dry tonnes and was granted planning permission in 1998 and was to have been opened up in 2004. However, a significant deterioration
in the market for fuller’s earth has rendered such a small deposit uneconomic and no working will now take place.
Steetley Bentonite and Absorbents Ltd, a wholly-owned subsidiary of Tolsa SA of Spain, formerly produced fuller’s earth near
Woburn in Bedfordshire. A planning application to extract fuller’s earth from a southern extension to the deposit (Wavendon
Heath South) was turned down in early 2001. The application was the subject of a public inquiry in September 2001 but the
appeal was dismissed by the former ODPM in July 2002. A challenge to this decision was made in the High Court in February
2003 but was also dismissed. Consequently fuller’s earth extraction ceased at Woburn in December 2004 with the exhaustion
of the remaining reserves and marking the end of a long history of fuller’s earth working in the area where it is thought to have
been extracted as early as Roman times. Large-scale extraction in the Woburn area by F W Berk Ltd (acquired by the Steetley
Co Ltd in 1970) started in 1951 and continued, with a small break between 1954 and 1957, until 2004. The current workings in
Aspley Wood started in 1961 and have continued with a series of extensions to the original permission. The Wavendon Heath
South site, covering some 54 hectares and containing some 320 000 tonnes of dry product, sufficient for about ten years output,
would have been the last site in the area. In recent years fuller’s earth form Woburn has been used almost entirely as a filler and
fibre retention aid in papermaking.
united Kingdom summary 2000–2004
Commodity 2000 2001 2002 2003 2004 2000 2001 2002 2003 2004
Tonnes £ thousand
Fuller's earth
Crude production 103 000 … 33 000 19 000 115 000
Sales (a) 65 500 52 000 (b) 44 200 (b) 34 000 (b) 28 000
Imports 6 563 5 896 9 115 7 085 2 574 780 611 849 697 316
Exports 429 121 74 254 124 157 80 61 53 59
(a) BGS estimates based on data from producing companies. Dry weight. (b) Including sales from stockpiles.
gas, natural (see Petroleum)
germanium
united Kingdom summary 2000–2004
Commodity 2000 2001 2002 2003 2004 2000 2001 2002 2003 2004
Tonnes £ thousand
germanium
Imports
Metal 75 7 10 4 2 1 845 921 478 595 1 982
Exports
Metal 37 10 0 3 1 1 039 668 82 18 86
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