14. Mines and Minerals.

Two important minerals are raised in our county, viz, coal and gypsum.

Open Working of Coal Seam, Erewash Valley.
Open Working of Coal Seam, Erewash Valley.

Coal has been used in Nottingham for many centuries. On one occasion Henry III had to leave his Queen in this town for a time, but she soon departed because she could not endure the smoke from the coal. In 1641 “stone coal” was got at Wollaton, Strelley, and Bramcote; and was conveyed to Nottingham and sent thence down the Trent to Newark, Gainsborough, and other places.

At first the coal was quarried in open workings situated on the outcrop of the seams. As the workings were carried forward the overlying rock became very thick, and rain-water ran down into the quarries, thus making it more difficult and expensive to get the coal. The miners then found it better to “mine” rather than quarry the coal, and so they went further east and sank shallow pit shafts to the coal-seams. The coal was then extracted from between roof and floor and the mine kept open by the erection of wood props. Because the seams sloped further into the earth those made later were gradually sunk more deeply. In the eighteenth century such mines existed at Bilborough, Brinsley, Eastwood, Teversall, and Wollaton. At the first-named place the coal was worked at a depth of 300 feet. In the middle of the nineteenth century engineers began to sink mines through the newer rocks, and since then many others have been sunk further and further towards the east, more especially in the Leen valley. Generally speaking the further east a mine is situated the deeper must it go. The most easterly ones at present are the Gedling and Manton pits. In the former coal is worked at a depth of 1377 feet. In the recent boring at Oxton, which is still further towards the east, the same seam was reached at a depth of 2030 feet. As the sinking of a shaft is very expensive, fewer mines will be put down in this part of the coalfield than in the west. On the other hand a greater area will be worked underground from one shaft. It may be expected, therefore, that the collieries of the future will be more widely spaced. The mode of working is called “Longwall.” Nottinghamshire miners are very proud of it and claim that it is peculiarly their own. It is now being adopted in all the other coalfields of England, and all over the world “Nottinghamshire Longwall” is spoken of with great admiration. By this system all the coal is extracted by workings which day by day advance further outwards. Thus after a life of 30 or 40 years the working places underground may be two or even three miles distant from the shafts. From the bottom of the shaft several spacious passages called “gates” radiate. These branch and rebranch until they reach the “working face” at many points. At the “face” the seam is seen to be several feet thick and is overlain and underlain with other rocks. As the collier removes the coal he places it in little trucks or “tubs.” Any waste or rock he has removed in winning the coal he builds up in the space behind. The loaded tubs are pushed on rails laid close to the face until they reach a gate. In the gates they are drawn by horses to the “haulage-planes” where they are attached to wire-rope cables and are transported by steam or electric power to the bottom of the shafts. Thence they are raised to the surface by powerful steam engines often at a speed of 50 to 6o feet per second.

Gedling Colliery.
Gedling Colliery.

Large modern collieries are capable of raising upwards of 3000 tons of coal during a working shift of eight hours. A single mine will find employment underground for considerably over 1000 men. Large volumes of air are therefore required for them as well as for removing the dangerous firedamp which escapes from the coal seams. There are two shafts to each mine, the wind goes down one and up the other, being drawn by a revolving fan which may circulate a current of 200,000 or 300,000 cubic feet of air per minute through the mine.

In this coalfield the most valuable seams are known by the following names :—Top Hard, Deep Soft, Deep Hard, and Furnace. The first of these, which is 4 to 5 feet thick, is the most important and is identical with the famous Barnsley coal of Yorkshire, though only half as thick. The distance in depth between the first and last is about 900 feet. In 1870 the output of coal in this county was only two million tons. There are now over 50 separate collieries, the output of which during 1908 amounted to 11,044,214 tons. This is about six millions less than in Derbyshire, one-third the output of Yorkshire, and one-seventeenth of that for the whole of England.

The Nottinghamshire coal-mining industry, however, is as yet only in its infancy. Its coalfield is part of a larger one known as the York, Derby, and Nottinghamshire coalfield. The Royal Coal Commission report in 1905 shows that the resources of this larger field are as great as those of South Wales and Monmouthshire, and that there is enough available coal in it to last another 500 years at the rate of production for the year 1903. This rate however increases year by year.

Gypsum is, of course, not such an important mineral as coal, but Nottinghamshire is the most important gypsum-producing county. In 1908 the total output for the county was 29,685 tons, which represented one-third of that for the whole of the United Kingdom. Gypsum is found in the Keuper mans and is obtained usually by running tunnels into the hillside for several hundred yards. A gypsum layer varies in thickness from 15 feet to a mere film. It may be continuous or be made up of ball-like masses. The purest mineral is roasted and ground up to a powder as fine as flour. This is plaster of Paris. It is also used as alabaster for making ornaments and ornamental building-stone. One form has a beautifully silky appearance and is called “satin spar.” This used to be found in abundance close to East Bridgford and is believed to have given origin to the name of a Roman station close at hand, viz. Margidunum, which probably means “Pearl Hill.” The presence of gypsum in the waters in the vicinity of Newark makes them hard but peculiarly suitable for brewing.

Other less special products of the ground are obtained.

The clays of the Keuper marl yield a medium quality of bricks. On Mapperley Hills extensive brickyands have existed for many years (see p. 26). These have supplied much of the building material for the neighbouring city. Hence the saying that “Nottingham was once on Mapperley Hills.” The Permian mans produce a better quality of bricks and tiles, and are also used for making coarse pottery.

The Magnesian Limestone yields an excellent building-stone, especially around Mansfield, where it contains much sandy material. It was from this formation that the stone was obtained for building Southwell Cathedral and the Houses of Parliament.

The limestone in the Lias, more particularly at Barnstone, is used for the manufacture of hydraulic cements.