Non-Metallic Minerals

A great variety of non-metallic minerals is produced in Britain. Various common rocks are mined for building purposes, heavy constructional work and for roadmaking, as in the case of granites in Devon, Cornwall and Aberdeenshire, and basaltic rocks in Northumberland, Shropshire and parts of the Scottish Lowlands. Sandstones and limestones have for centuries been used for the construction of houses. Limestone is used also in the chemical and iron and steel industries, as well as to provide lime for fertilizers, for road-making and also for cement manufacture. The Pennines are especially rich in sandstones and limestones, and Yorkshire and Lancashire are the leading quarrying counties.

Deposits of clay, especially in the Bedford and Peterborough areas, are important in the manufacture of bricks, while slates in Cumberland and North Wales have been extensively quarried as roofing materials. Fireclay, often found under coal seams, is used for making bricks suitable for lining furnaces.

Chalk is used in the cement industry and is mined on both banks of the Thames estuary, the South Downs and on the banks of the Humber.

Sand and gravel for the building industry generally come from pits which are fairly widespread throughout midland and northern England and central Scotland, and on the river terraces in the Midlands and southern England. Certain special varieties of sand are used in the glass-making industry, and these are concentrated in Bedfordshire, Norfolk and Lancashire.

Kaolin, a fine, white china-clay, occurs in Cornwall and Devon. It is shipped for use in cotton, paper and pottery manufacture.

Common salt and rock salt form the basic raw materials for a variety of chemicals essential, for example, in the textile and soap-making industries, so they have their chief market iii the chemical industry.

Important areas of the concentration of common and rock salts are Cheshire, Worcestershire and Teesside. Deposits which exist 24—26 m below the surface represent the site of an inland sea in former geological times, the waters of which have long since been evaporated.

Certain other less common minerals are also obtained in Britain, although in smaller quantities: gypsum occurs in semicrystalline form and is used to produce plaster of Paris and alabaster. Potash has been proved to exist in workable quantities in North Yorkshire. Peat is widespread on upland moors or lowland fens and dug for fuel. The main peat areas are the Central Plain, Donegal and the western peninsulas of Ireland. It is now being used for the generation of electricity, but is still used domestically in North-West Scotland, the Southern Uplands and the Cheviots.

A brief survey of the natural resources of Great Britain reveals the absence here of many minerals which are important for the development of a number of branches of modern economy.

Water

Britain's water supplies are obtained partly from surface sources such as mountain lakes, streams impounded in upland gathering grounds and river intakes, and partly from underground sources by means of wells, adits and boreholes. Water for public supply in Britain amounted to about 19,500 megalitres (Ml) a day in the second half of the 1980s and average daily supply per head was nearly 350 litres.

Дата добавления: 2015-08-21