Iron Ore Mines
By the time the railways came along iron ore was the most important mineral being mined. British iron ore deposits are mainly found in the North of the country, which coupled with the similar dispersion of coal reinforced the trend for heavier industries to develop in those regions. In the period between the two world wars the iron and steel industries migrated to Lincolnshire and Northamptonshire where large new steelworks were erected.
Fig ___ British Iron Deposits
British ores tend to be of indifferent quality however, so there has always been a significant import of higher quality ores from abroad.
The most common ore type in England is a dark ore commonly called Spathic, the technical name is Siderite and chemically the material is iron carbonate. Siderite is often found mixed with either clay or coal deposits, mixed with clay it is called ironstone, when mixed with a coal deposit it is called blackband ironstone. Siderite is a poor quality ore, in Britain typical specimens contain just over thirty percent iron. This kind of ore forms deposits of so called 'Jurassic' iron ore found in a chain along the northern face of the limestone escarpment running from Bristol via Banbury, Kettering and Scunthorpe to Cleveland. These ores are acidic, that is they contain phosphorous, and could only be used after 1879 when Sidney Gilchrist Thomass came up with the idea of adding limestone to the smelting furnace. As about half the iron ore on earth is contaminated with phosphorous this virtually doubled the worlds potentially available steel.
The Churnet Valley railway (part of the NSR) had a number of iron ore mines producing a cherry red ironstone in the valley between Consall Forge and Froghall and Ipstone and Kingsley. Many millions of tons of iron ore were found from 1853 up to 1923 when the last mine, Cheery Eye Mine closed. Iron works had existed in the valley from the 13th century but by the mid 19th century most of the works had closed down.
The most valuable of the Jurassic ores is 'Brown Haematite' or 'Limonite', which is actually iron oxide,and British ores contain about forty percent iron. These ores also contain phosphorous and water (in varying quantities) and one major source is Northamptonshire. Limonite is yellow in colour, hence the name, and has been used as a pigment (yellow ochre) for thousands of years. Where this ore is found mixed with clay it is usually a dark colour and is called Ironstone (hence ironstone hoppers on the railway).
The main source of British ironstone was at Cleveland but it was also mined as far afield as Seend near Devizes in Cornwall. As the ore lies close to the surface a form of strip mining has long been employed.
First diggers remove the top soil and place this to one side. Next the soil lying over the seam of ore is removed, this is usually used to fill in an already worked area. The top soil is then put on top of this and the land returned to agricultural use. Meanwhile coal in the form of poor quality odds and ends with a large proportion of dust (technically called 'slack) is dumped on top of the exposed ore. Diggers then work their way along, picking this mix up and dumping it behind as they go. The mixed iron ore and coal is set alight and the coal calcines the ore. Once the ore is cool enough a third digger puts it directly into railway wagons.
This method results in a pleasing modelling arrangement as shown below which being long and thin (a minimum of only four or five inches) has potential as a screen in front of a hidden fiddle yard or hidden return loop.
Fig ___ Ironstone mining in Cleveland area
For exhibition purposes the mechanical shovels and drag crane could be made to move and you could add a smoke unit under the burning mix of ore and coal. The railway line serving the cutting would normally be worked by a works loco, in most cases the line would feed direct to the steel works. If the ore was to be shipped to a remote blast furnace exchange sidings would allow the railway company loco to collect and deliver the wagons.
Magnetite ore, which is dark reddish grey to black, has been mined in the West of England but the deposits were small and soon exhausted. Magnetite is the richest iron ore with a typical iron content of up to sixty percent. Magnetite is of course the 'lodestone' used in early magnetic compasses, it is named after Magnes, a Cretian shepherd who according to legend found the nails of his boots stuck to the rock on which he was standing. Britain has been importing quantities of magnetite since the 1930's at least (possibly before), mainly from Sweden and Norway.
Of the remaining ore deposits occurring in the UK the most valuable is Haematite otherwise known as Red Ochre and chemically iron oxide. This ore was the best in Britain and contains up to 20% iron, as a comparison the yellowish Leicestershire ore contains only 2%. Unfortunately Haematite was only found in the area of Barrow in Furness where the ore is dark grey to black, and Glamorgan where the ore is reddish brown to grey. Deposits in both these areas were exhausted by about 1960. Similar reddish brown ores in the Forest of Dean were worked out some time before the Second World War. By the early nineteenth century Britain was importing quantities of brownish red Haematite ore from the Bilbao area of Spain and these imports have continued.
Since the early 1970's imported iron ore has often been shipped in 'pelletised' form. The iron ore is ground to a powder and mixed with water, the resulting mix is passed to a balling mill which rolls it into small balls about the size of large marbles. These are dried and shipped in bulk, they are reddish brown in colour.
In order to make iron and steel alloys there were considerable imports of related ore types, notably Chromium, Manganese, Molybdenum, Nickel, Tungsten, Cobalt and Vandium. After the Second Word War however the countries producing these ores began locally refining them and selling the much more valuable metals in ingot form.
The iron is smelted at large iron and steel works, these are considered separately in Lineside Industries - Iron and Steel Works & Stockholders.
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