Humberside Geologist No. 14

Humberside Geologist Online

The real mineral resources of the United Kingdom

Peter W. Scott, Camborne School of Mines, University of Exeter,

Redruth, Cornwall TR15 3SE

 

The mineral resources of the UK include oil and gas, coal and a group known as industrial minerals. The UK is no longer a producer of metal ores, the last tin mine in Cornwall closing in 1998. Industrial minerals include construction raw materials as well as china clay, ball clay, salt, potash and many others (Table 1). They have a value of more than £2 billion annually. More than 20,000 people are employed extracting these minerals. Further value is added by processing and manufacture of products, resulting in a £multibillion contribution to the UK economy. Industrial minerals are essential raw materials for the UKís basic industries, such as agriculture, construction, ceramics (including glass), iron and steel, plastics and paint, chemicals and paper.

China clay (kaolin) produced from the St. Austell granite in Cornwall and the SW side of the Dartmoor granite in Devon are used principally in papermaking and to a lesser extent in ceramics, paint and plastics. It is Britainís major mineral export. Ball clay from the Tertiary Bovey and Petrockstow Basins in Devon and the Wareham area of Dorset are principally used in the ceramic industry. The kaolinite in these clays are finer grained, more disordered in their crystal structure, and more ragged in their shape, giving them increased plasticity compared with the kaolinite in china clay, which has a mixture of individual pseudohexagonal crystals and larger stacks.

Limestone is found in many geological formations from the Cambrian Durness Limestone to the Cretaceous Chalk. Carboniferous limestone is a particularly important resource providing a source of aggregates and high purity stone for chemicals, lime and glass. It is used for cement and, in powdered form, it is a mineral filler in paint, rubber and plastics.

Aggregates are made from either crushed rock (limestone, dolomite, quartzite, sandstone, igneous rock and some others) or sand and gravel. Large crushed rock quarries, some producing over five million tonnes per annum, are situated in Leicestershire and Warwickshire (igneous and metamorphic rocks) and in the eastern Mendip Hills (Carboniferous Limestone). These are the nearest hard rocks to south east England where there is a major demand for aggregate. Some other important areas for crushed rock are northern England (limestone, greywacke and dolerite), eastern England (Permian dolomite and limestone), and the Welsh borders (quartzite and igneous rocks). Although sand and gravel occurs in large amounts in south-east England as fluvioglacial terrace and plateau gravel deposits and in East Anglia as glacial gravels, its production is diminishing because of sterilisation of resources through urban development and the difficulty of obtaining planning permission in this densely populated area. The imposition of a primary aggregate tax of £1.60 per tonne from April 2002, opens up an opportunity for aggregates made from china clay waste to be transported by ship from Par docks in Cornwall for sale in the London area.

High grade quartz sands are used in the foundry industry and where the iron oxide content is very low, it is a source of silica for glass-making. Such deposits occur in the Lower Cretaceous Greensand in Surrey, Leighton Buzzard and Kings Lynn. Other sources of glass sands are Carboniferous Namurian sandstones (Staffordshire) and Recent sands in Cheshire. A very high purity sand is mined by an underground room and pillar method at Loch Aline, Morvern, Scotland. It is used for high quality crystal glass, ceramics and for making fused silica refractories.

Salt of Triassic age is mined in Cheshire and potash is extracted from a deep mine in North Yorkshire from similar aged strata. Triassic strata also provides a source of gypsum in Nottingham, Yorkshire and Cumbria. Fluorite production from veins and replacement deposits in Derbyshire and the Northern Pennines is much reduced in recent years. Some barite is mined in Scotland, and talc from Unst in Shetland.

Other materials for construction include slate from Delabole in Cornwall, North Wales and the Lake District, common clay from many geological formations for brick and tile making and dimension stone from granite, limestone, sandstone and others.

If the UK did not exploit its own natural resources they would have to be imported, or more likely, we would import the products made from industrial minerals extracted elsewhere. Jobs would be lost and there would be a major effect on the UKís economy. Some will argue that we should not continue to extract our indigenous resources because of the environmental damage that results, or perhaps more aptly, because it is "in my back yard" (NIMBYism!). Mineral extraction damages the environment wherever it occurs, in the same way that any development of land, for example by intensive agriculture, deforestation, afforestation, or a housing estate, irreversibly changes it. Past mining and quarrying in the UK has left its mark on the landscape, but its visual impact has been considerably reduced in recent years through, for example, the removal or careful design of waste tips, the reinstatement of land back to agriculture or other post-mining restoration. Many former quarries are now nature reserves in which there is an even greater biodiversity than before mineral extraction commenced.

The mining and quarrying industry in the UK is highly regulated, with regards to the safety of the workforce, emission of noise, dust and chemicals into the air, and controls on the quality of water discharges. There are agreements with local planning authorities on methods of working and restoration and sometimes even lorry movements or times of working. These are all rigorously enforced. Such regulations and agreements do not exist in many other countries, or if they do exist, are not enforced or are ignored. In poorer countries mineral extraction is mainly unregulated, inefficient and resources are often exploited in a haphazard manner. Even in some developed countries, the protection of the environment does not assume the same high priority as in the UK. Therefore, if we imported our industrial minerals from overseas, we would be adding to world environmental degradation, squandering finite resources, and condoning unsafe practices which lead to injury and premature mortality. This is a moral issue which should be addressed by politicians, and understood by those who would argue that the UK does not need to extract its own industrial mineral resources.

We are in a post-metallurgical era where industrial minerals are required in even more quantities for new materials, such as special ceramics, plastics, coatings and composites. These materials are replacing metals in many applications, and industrial minerals are engineered to provide the required properties. A healthy industry extracting and processing industrial minerals is important for new products for the 21st Century, as well as for providing the raw materials for the continuation of our basic manufacturing industries.

Table 1.

Industrial minerals extracted in the UK in 2001

Sand and gravel, igneous rock, sandstone, limestone (including chalk), dolomite, salt, potash, gypsum, common clay, china clay (kaolin), ball clay, fireclay, fullerís earth (bentonite), china stone, barite, fluorite, silica sand, talc, slate, dimension stone (granite, marble, sandstone, limestone, serpentine), peat.

(published as a web-page August 2002)

 

(c) Hull Geological Society 1999 + 2007