Mining and Smelting Non Ferrous Metals
Britain was the worlds largest producer on non ferrous metals up to the late nineteenth century when the mines went into rapid decline. In the 1860's Cornwall was producing nearly half of all the worlds tin, by the 1930's it was producing only about one percent. Copper production in the 1850's was running at over three hundred thousand tons a year, within ten years this was down by a third and twenty years later it was down to less then forty thousand tons a year, precipitating the collapse of the Swansea smelting industry. Lead also went into decline in the later nineteenth century but here the fall in production was not so rapid and lead mines continued to operate into the 1970's.
Fig ___ Non Ferrous Metal Mining Areas
By the end of the 17th century most of the surface outcrops had been exhausted and metal mines had evolved as deep mineing methods were developed. The sketch below shows a typical lead mine dating back to the earliest days of the railways, the image is made up from elements from two actual mines and includes a Cornish style beam engined pump. These would serve as the core buildings for most non ferous metal mines.
Fig ___ Sketch of a lead mine
The buildings shown represent the mine head gear, there would also be a number of small supporting buildings, an office, stores and perhaps a small stables. The ore from these mines was usually partly processed or 'dressed' at the mine site before being shipped out (typically in three, four or five plank wagons, with the three plank type being the most common).
By the time the railways arrived the standard approach was to first crush the ore, using heavy stone rollers or by the later 19th century falling trip-hammers operated by a water wheel or a steam engine. The pea sized ore was then placed in an inclined trench called a buddle and water was run over it, this separated the valuable ore from the unwated waste.
The ore was then taken to the smelting works, where a similar crushing and washing process was re-done before the ore was processed to recover the metal.
As noted above imported ores became increasingly important in the later 19th century, notable ports being Liverpool, Widnes, Swansea, newcastle and the Thames Estuary all of which supported relatively local smelting works
Lead, Zinc, Copper and Tin ores were all sulphurous (lead sulphide, zinc sulphide and reddish brown Copper Sulphide) and many smelters handled a range of these materials, so the smelters often described themselves as smelting 'sulphides'. The smelter would also recover a range of materials from the ores, sulphuric acid was a valuable by-product but they might also recover arsenic, silver and a range of other trace metals and other contaminants.
By the mid 19th century the standard furnace used for separating the metal from the ore was the reverbatory type, in which the coal used to heat the furnace is separate from the ore, the heat being reflected down from a curved roof. See also Prototype and Model Buildings and Structures - Prototype industrial ancillary structures for a full description of this type of furnace and how it works.
These furnaces were inside buildings but there were usually plenty of openings in the building and you might wish to add a representation of the furnace. They were rectangular, made of brick and had H section girders set along the sides and at the corners.
In N scale a scrap of half inch (12.5mm) wood one and a half inches wide (37mm) and three inches long (75mm), cut as shown below makes a fair representation. Cover this with 'sooty brick' brick paper and add the uprights using matchstick for the heavy hopper supports and small cocktail stick for the rest. The rods across the top are probably not going to be visible but you can use thread for these. The hopper can be roughly carved from half inch by half inch strip. The example shown below is sketched from a furnace in a copper smelters but would serve for any of the metals discussed.
Fig ___ Furnace for copper smelting works interior
A modern smelting works often combines the smelting of several metals, the example shown below is typical of the type of establishment built since the end of World War Two (some plants this size were built before the war), clearly something on this scale is somewhat impractical for a model railway.
Fig ___ Typical modern smelting plant
A generic smelting works can be represented using commercially available 'heavy industrial' buildings, although additional chimneys would be needed for these. They are still rather large but by using selective compression you can establish the nature of the works and include the essential elements.
Fortunately there have been smaller works, more amenable to railway modelling, and the examples illustrated below were all selected from these smaller establishments.
Traffic inwards would include coal and ore, the latter probably in three plank open wagons up to the late 1930s. For a post 1960s layout you might also see gas tank wagons, mainly delivering oxygen, at a larger works.
Traffic out would be ingots of metal, in vans or sheeted opens (these were valuable goods) and sulphuric acid in glass carboys from a smaller works, in tank wagons from larger establishments. The trace materials recovered would tend to go out in vans (particularly any silver ingots, which were very valuable indeed).
Index for Specific Metal Mining and Smelting Industries
The various metals covered in this section each support an independent industry, each having its own distinctive structures and in some cases railway rolling stock. Sketches of some of the buildings and rolling stock are included under their respective industries.
Note: Brass and bronze are discussed under Foundries
Aluminium is discussed separately
Lead
Lead mines once proliferated in the limestone areas of Britain, mainly Derbyshire, Somerset and the Yorkshire Dales, the main production area was the Peak District (Millclose was the nation's largest lead mine, it closed in 1939), however lead is found (and has been mined) in all the highland areas of the country. At the end of the nineteenth century over half the worlds lead was produced in Britain but by the 1960's lead mines were only in operation at Alston Moor on the Cumberland/Northumberland border and in North Derbyshire. Notable lead mining areas were located at Crooked Oak in Southern Northumberland, Newborough also in Northumberland, and in South Wales in the counties of Glamorgan & Gwent (Nant y Mywyn mine at Llandovey in Dyfed was the biggest lead mine in South Wales, opened in the late eighteenth century it finally closed in 1932). After the lead mines closed there was a fair bit of re-working the waste material from the spoil heaps to recover fluorspar (calcium flouride used in steel making, glass manufacture (and in place of glass for some specialist camera lenses) and the production of hydrofluric acid. Blue John is a type of fluorspar), barytes (barium sulphate, used in paper making and in the manufacture of paint as well as an additive to cement) and calcite (calcium carbonate, used in cements, mortars, glass making and for ornamental purposes).
Lead is mined in the form of Galena, naturally occurring lead sulphide (PbS) which is appropriately enough lead grey in colour and usually associated with limestone deposits. The ore is sometimes called 'backstone' in older texts. Early lead mines were shallow affairs but by the 17th century deeper mines were the norm as the surface deposits were worked out. This meant that water became a problem in many mines and adding a drainage tunnel or 'sough' was common practice, later supplemented by horse 'gins' and steam pumping engines.
Once the ore has been mined the lead has to be extracted, or smelted. Step one is to dress the ore, basically break it down to about pea size, then crush it to a powder. The powder is then mixed with water to separate the heavy ore from the lighter waste materials. This was done in various ways for details of which see also Mines - General introduction, it is worth noting that in lead mines this work was often done partly underground, where the water being drained into the sough could be employed and as a result less waste was lifted up the shaft. If your model is set after about 1870 the crushing and separation was done in a large buildings, driven by steam or a water wheel. One large water wheel remains at Park Level Mill at Killhope in the Pennines, when it was set up in the 1870s there were many lead mines and many water wheels in the area. Killhope is the most complete lead mining site in Britain and restoration of the machinery is continuing.
Lead mines often did not have the substantial pit head gear associated with coal mines, it was not unusual for a single engine house to operate several shafts, with the lifting wires arranged on a series of grooved wheels mounted on short (9 foot) supports. Any pit type mine would be likely to require a pump (where an adit or drainage tunnel could not be laid in), one of the more common early steam types was the 'Cornish' pump engine, these large beam engines were used all over the country not just in Cornwall. They remained in use in the 1930s, although alternatives such as electric pumps were by that time available, see also Mines - General introduction.
To extract lead from galena (Lead Sulphide, PbS) the crushed ore is heated with a limited supply of air, this was done in a brick furnace, broadly similar in appearance to the common beehive type bound with iron bands and associated with a tall chimney. Once the mix has been sufficiently heated the air supply is then cut right off. The net effect of this is that the sulphur is driven off as a gas, mixed with oxygen from the early part of the process (most mines simply vented this to atmosphere). The unwanted muck floating on top of the molten metal would be scraped off then the lead would be drained from a tap hole.
Small mines used a small hearth to melt the ore, requiring nothing more than a substantial building with a chimney. In the late 18th century the London Lead Co developed a variation on the reverbatory furnace (which has fuel on one side, ore on the other and a domed roof to reflect heat from one to the other) which soon became the most common way of melting the ore at larger works. The flues feeding the chimnies for the furnaces were often taken some distance underground, this allowed some of the polutants to selltle, but brought with it the unleasant job of scraping condensed lead from the walls.
By the end of the 19th century the blast furnace was increasingly used for smelting lead. Photos are hard to find, the sketch below is based on a tracing I made some years ago from a rather small photo in a book. The furnace (the circular tower on the left) appears to be clad in concrete, the tower on the right appears to be clad in either vertical wooden planking or corrugated iron sheeting (or so it says on my notes). The purpose of the chute on the right of the tower was not apparent, it may however have been used for loading mine spoil into railway wagons. The narrow gauge tracks at the bottom bring in tubs of prepared ore to the tippler (the elevated timber 'shed' at the base of the tower housing the mechanism for this)
Fig ___ Sketch of a lead smelting plant
In the blast furnace the ore is mixed with coke and limestone and the slag and molten lead is drawn off at the bottom as with steel. One difference however is that the air blast pipes are attached just above the base crucible, so they blow across the top of the slag and molten lead. The sketch below was prepared at the time I made the tracing, it is a rough drawing showing the dimensions estimated from the photo.
Fig ___ Rough sketch of smelter showing approx dimensions (British N)
There are usually impurities in lead which require removing, some such as silver actually make this a profitable exercise (quite a few mines were named 'lead and silver mine' and some galena is mined primarily to recover the silver). A lead smelting works would not be located close to a town after the mid 18th century but would probably be rail served.
The lead was run off into sand moulds where it formed ingots or bars called pigs, typically weighing in at about 130 lbs (about 60Kg). Lead is heavy stuff, a pig about four inches square would be about eighteen inches long, a ten ton wagon carries 10200 Kgs so would hold 170 pigs of lead. This requires very little height and at least one lead smelter in Wales operated some low sided wagons, as the lead is valuable these had a pitched roof. After several house moves I was not able to find the photograph, the sketch below is from memory and may be inaccurate in detail (an amended drawing will be added when the photograph has been found). A model could be made easily using the Peco 'salt wagon', simply cut the sides down to three planks in height and fit the roof, the remaining 'four plank' frame can be used to make a four-plank wagon (on a second Peco chassis) or cut down and fitted with a roof from a second salt wagon kit on a spare chassis (you need the coupling plugs from the chassis kit), this leaves you with a standard seven plank wagon body and chassis.
Fig ___ Lead company PO wagon (provisional drawing)
At some works the lead was further processed on-site, usually to produce rolls of lead sheet, but a lot was shipped off to other works for forming into sheet, tubing etc. Lead being exported was shipped in rolls, about 3 feet long by a foot in diameter and it seems likely that this was a standard size for inland traffic as well. To handle the rolls they used a length of chain with an L shaped hook on each end, the hooks were inserted into the ends of the roll to lift it.
Lead smelting works close to the coast sometimes imported the ore for processing (notably from France and Germany).Notable lead smelting works were located in Wharfdale, Nidderdale, Airedale, Craven, Rossendale in Yorkshire whilst Swaledale and Wensledale (again in Yorkshire) became important in the nineteenth century. Other works were located at Hengistbury Head Dorset, Combe Martin and Here Ferrers in Devon, County Durham and Teesdale. Lead smelting in Derbyshire started in about 1570 using a simple ore-hearth bellows fed then coal fired reverbaratory or cupola in about 1737. Smelters in the upper Dove valley around Greenlowfield, Mill Dale, Ellastone and Crakemarsh produced lead, zinc and copper.
Lead has many uses, it was added to glass to make 'lead crystal', it was used in pottery glazes, more recently it has mainly been used for making motor car batteries and in the manufacture of TEL (Tetra Ethyl Lead) the anti-knock agent that was used in petrol until the 1990s.
White lead is lead carbonate, it is used in paints (this is the paint that turns black on exposure to sulphurous pollutants in the air), up to the 1960's about a fifth of the lead used in Britain went into paint in this form. It is made by allowing a lead sheet to oxidise for several weeks in a warm atmosphere containing water and ascetic acid (vinegar), the white powder forms on the surface and is scraped off.
Red lead is lead oxide (Pb3O4) produced by heating lead in contact with air. Red lead is used in glass manufacture and mixed with linseed oil as a cement for joining lead pipes which were used for domestic water and gas up to the 1970's. Lead oxide comes in various forms however and the reddish brown form known as Litharge is used in making lead glass.
Lead has been used for lining sheaths on electrical cables as it does not rot, about a fifth of all the worlds production was used in this way prior to the development of petrochemicals and plastics in the 1960's. The third major use is of course in batteries such as those used in motor vehicles.
A tin-lead alloy was used for toothpaste tubes and similar, the mix being slightly different from that used for solder.
Lead was also widely used for sheathing electrical cable,
Other minerals associated with lead, such as fluorite, baryte and calcite, were traditionally regarded as waste but in the post war era these have proved valuable (lead is no longer mined in the Peak District but fluorite is an important commodity).
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Zinc
Zinc (or spelter) was first produced in Britain in the 1730s, there are large deposits of Zinc on the island of Anglesey, however these have never been fully exploited. Zinc is often found close to lead and was exploited by lead mine owners, always in need of additional income. The zinc smelting plant was often combined with a lead smelter (they were sometimes combined with a copper or tin smelter as well). Notable Zinc mines include a large establishment at Batws Y Coed operated by the chemical company Brunner Mond up to 1906. Brunner Mond wanted zinc sulphide for use in making chlorine from the calcium chloride produced at their soda ash plant at Northwich (Cheshire). This mine re-opened for a time after the First World War but was not a success.
Although brass had been known about for centuries it was only in the 17th century that the Chinese found out how to obtain pure zinc, and it was in the 1780's that someone in Bristol worked out the method (the key was keeping the process out of contact with air). Zinc is used for making brass (7 parts copper to 3 parts zinc), bronze (eight parts copper, ten parts tin with two parts zinc) and for 'dry batteries', the majority of the metal however is used in coating iron to produce 'galvanised iron'. The iron or steel sheets are cleaned then dipped in molten zinc, most zinc plating is done in the West Midlands. Zinc Sulphate (ZnSO4) is used with water to produce 'white vitriol' and when this is mixed with barium sulphate you get a white powder precipitate. This is used in white paint, it does not cover as well as white lead but it does not turn black on exposure to polluted air (this was used to good effect by the Midland Railway, the markings on their wagons being noted for not darkening as much as those on other companies goods stock).
The ore from the mine is separated in a foam bath of water and pine oil (as for copper), the skimmed froth is the useful part. The zinc ore (which is mainly zinc sulphide) was first roasted, the sulphur is driven off and passed into a tank of sulphuric acid which is periodically diluted with water, a surplus being sold off. Sulphuric acid produced in this way is a major by-product of zinc smelting, up to 2 tonnes being produced for every 1 tonne of zinc in some smelters.
The roasted ore was then mixed with either anthracite coal or charcoal and put into clay retorts (similar to those in gas works). When this mix was heated the zinc metal was given off as a vapour. This condensed in the cooler part of the retort and was collected as molten metal in iron containers. The early horizontal retorts were operated as a batch process, emptied between each firing. They were replaced in the 1930s by improved vertical retorts in which the process was continuous. For these retorts the calcined ore was made into small briquets before being fed into the retorts. The retort method of production was replaced by electrolytic refining but I understand some plants remained in use into the 1970s.
The use of electricity to extract zinc was developed during the later 19th century but it was World War One before a working electrolytic zinc plant was established (using zinc chloride solution to produce zinc and chlorine). In the more modern electrolytic process (introduced in the later 1930s) the ore is first calcined or roasted as before, driving off the sulphur to make sulphuric acid, but this is then used to leech the zinc metal from the ore. Some pure zinc is then added which causes the contaminants to be reduced and these fall out of the solution. The resulting zinc laden liquid is then passed through baths where electricity is passed through it and the zinc is deposited on the aluminium cathodes. This requires an awful lot of electricity and these smelters would probably have a line of pylons into the works.
From the photographs I have seen there were no buildings or structures that would definitely identify a zinc smelter, any large single storey 'heavy industrial' buildings would serve. One characteristic feature of zinc smelting works appears to have been a very tall chimney (the Britannia works in Avonmouth featured a 100m (300ft) concrete chimney).
Traffic into the works would include mineral wagons carrying anthracite along with three plank opens carrying the ore. Outgoing would be the zinc ingots, these tend to be rather short and wide, however they are also cast as very large blocks (which would require a crane to shift them). Also outgoing would be sulphuric acid, in carboys from a smaller works or tank wagons from a larger establishment.
Fig ___ Zinc ingots on a pallet
From the mid-nineteenth century Britain's most important group of zinc smelting works was established at Swansea and the area remained Britain's main location of the industry. By 1914 works in Swansea were smelting 54,000 tonnes, 20% of the national total. In the 1920s there were six zinc smelters at work in Swansea (four of these were sited along the Swansea Vale Railway, including the Imperial Smelting Corporation Works in Llansamlet). These works smelted most of Britain's zinc ores and also imported considerable amounts. The industry mostly produced zinc ingots, a lot of which were used to make galvanised iron sheet at large works in the Swansea-Llanelli-Neath region. Zinc smelting came to an end in Swansea Vale in the early 1970s.
I think the last British zinc smelting works were at The Britannia Zinc works at Avonmouth, near Bristol, which closed in 2003. The nearby BZL smelting works in Avonmouth had closed some time earlier. The plant produced on average 90,000 tons of zinc and 35,000 tons of lead a year.
Notable zinc smelting companies include the Avonmouth based Imperial Smelting Corporation, they were advertised as Zinc smelters and sulphuric acid manufacturers in the mid 1930s. In 1968 a new Zinc and Lead smelter was set up, at the time the world's largest (I think the works was at that time trading as National Smelting Co.
The Eyre Smelting Co was in operation making zinc based bearing linings from before World War One until at least the later 1930s, they were based at Tonbridge in Kent (their bearing works was in Merton Abbey, London).
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Copper
Copper came to prominence in the UK in the 17th and 18th centuries, mainly because of a Mr Thomas Williams, known as The Copper King. He set up the Parys Mine Co in the 18th century to recover copper from the great deposits on Anglesey. He shipped the ore to St Helens in Lancashire or down to Swansea for smelting. The resulting ingots were then transported to the Greenfield Valley in Flintshire to be made into saleable goods. One of the most important were the copper bolts made to hold copper sheet onto the bottom of ships, preventing the torada worm from eating into the hull. The bolts were made by a sectret process and gave both the British Merchant and Roayal navy a real edge at sea (they are credited with making a difference to the speed of the British ships at Trafalgar).
In the 1850's Britain produced about half of the worlds copper, by this time most came from mines in Devon and the inland riverside port of Morewellham was, in Victorian times, the worlds most important copper port. This port was abandoned when the industry slumped toward the end of the nineteenth century but was partially restored in the 1970's as an open air museum. There were copper mines elsewhere however, there are some remaining buildings at Ecton in Staffordshire and there were a number of productive mines in Cumbria, although the import of cheap foreign ores had killed virtually all British copper mines off by the early 20th century.
Copper required large amounts of coal for the smelting and refining processes and it was deemed more economical to ship the ores up the Bristol Channel to the source of fuel. Although there had been earlier smelters at Bristol and the Wye Valley, the principal nineteenth century smelters were sited on the South Wales coalfield, centred on Swansea, with others at Llanelly, Neath and Port Talbot. At one time Swansea dominated the world market and called itself Copperopolis.
Copper ores come in a range of colours; Chalcopyrite (Copper Pyrites CuFeS2) is yellow, Bornite (Cuprous iron sulphide) comes in many colours, it is known as peackock ore, Cuprite is Cuprous Oxide and is ruby red, Malachite (basic carbonate) is bright green, Azurite (also a Basic Carbonate) as its name suggests is blue and Copper Glance is the reddish brown Copper Sulphide.
British copper ore is usually of the Glance type. In the mid 1850s William Henderson, of Glasgow invented a simple method for smelting copper by roasting the burnt pyrites with salt and washing out the copper with water. In more modern smelters the ore is crushed and ground in water, pine oil is then added and the mixture churned up, a foam forms on the surface containing most of the copper iron sulphide which is then skimmed off. Smelting follows a preliminary roasting, limestone or silica (sand) or both are then added and the mix is heated in a reverbatory furnace. The iron forms ferrous silicate slag floating on top which can be skimmed off. The remaining mix, known as 'matte', is placed in a vessel similar to a Bessemer converter and air is blown through it, this results in nearly pure copper being left behind whilst sulphur dioxide is given off as a gas (this can be recovered to make sulphuric acid). There is some sulphur dioxide left in the metal however, causing blistering on the surface of the copper ingots, which for this reason are called 'blister copper'. Blister copper is 98% pure but electrolytic reduction can improve this to 99.99%. Other useful byproducts from copper smelting included gold, silver and other precious metals, although only in small quantities.
With the growth of imported copper ore during the later 19th century there was a trend to locate new smelting works close to coastal towns, although there was also a trend toward importing copper in ingot form, refined in the country of origin. As imports increasingly focussed on copper ingots the smelting firms diversified into manufactured copper, refining, rolling sheets and plates and making tubes in copper and yellow metal. I have not traced any reference to copper smelting in the UK after about 1925.
Modelling a minimal representation of a copper smelting works for a pre-grouping layout is straightforward, a large building or group of large buildings with several large chimneys (typically there was one per furnace I believe).
Fig ___ Copper smelting works for a layout
The ore would arrive, probably in three plank open wagons (possibly 5 plank mineral wagons) and would be stockpiled as shown, it would then be barrowed into the works (possibly up an incline into the upper part of the building). Covering the stockpile would reduce the amount of rain water it would hold, and hence the coal required to process it, but I have not yet found a good set of pictures showing the actual arrangements on the prototype.
The traffic out would mainly be copper ingots, up to about World War One these were long and rectangular but with a series of 'bumps' along the top. I gather this was because when they cast them they laid bars in the bottom of the mould to lift out the ingots, apparently this was to an Admiralty specification (presumably this shape made them easier to secure on board ship (The Admiralty was for many years the largest single consumer of copper in the world, they beat it into sheet to cover the bottom of the wooden huled ships). The Admiralty standard one hundredwight ingot (112lbs or about 50Kg) were about five feet long.
Fig ___ Copper ingot from World War One
These could be remelted along with other metals to make brass and bronze products. By the later 19th century many copper smelting works used rolling mills to produce sheets and plate as well.
The sulphuric acid produced as a byproduct of the smelting process would probably be shipped out in glass carboys, or acid tank wagons (the demountable iron tanks (as available from Fleetline) came in after the smelting industry had wound down). Also outgoing would be the slag produced in the furnaces, probably shipped out in three plank wagons but (as far as I can tell) this was then just dumped.
As the market shifted and imported copper ingots began to dominate the UK market several factories were converted to manufacture copper goods such as plate, wire and tube. For a factory in the 1930s this would proably be the function of an existing 'copper works'. The older buildings would have been modified over time but there would still be multiple chimnies as the coper was melted to prepare it for reworking. In the sketch below the openings in the upper wall have been bricked up and the end wall of the left and building has some corriugated iron cladding.
Fig ___ Converted copper smelting works
Post war the works would receive imported ingots. In the post war era, by the 1950s, the ingots were normally stacked in ten layers of five ingots laid alternate ways and sitting on a pallet. These might be sold on to foundries or they can be melted down and reformed into larger billets (called Cakes, rectangular slabs anything up to 8 inches (20 cm) thick and up to 20 feet (8.5 m) or so long), these are rolled out to make copper plate, strip, sheet and foil. Coils of copper rod about half an inch to an inch thick (12mm - 25mm) are sent out to wire drawing works and cylindrical billets typically eight inches (200mm) in diameter are sent out to pipe makers.
By the 1960's 40 countries were between them producing over three and a half million tons of refined coper a year but 80% came from the USA, Chile, Zimbabwe (then still Rhodesia), Russia, Canada and the Congo (in that order). Copper is today the second most widely used metal after iron, it is second only to silver in its ability to conduct electricity and heat so it is used in boilers, condensers, radiators and the like as well as in electrical wiring and other equipment. Today over half the copper produced goes into electrical equipment, copper wire containing manganese has a high electrical resistance, it is called 'resistance wire' and is used to make the 'elements' for electric fires and toasters. Copper is used as an exterior cladding on buildings in the form of thin sheets nails down, it is more resistant to corrosion than iron as it forms a green coating (of hydrated basic carbonate) on the surface. The dome of St. Paul's cathedral in London, and the Statue of Liberty in New York are both coated in copper sheet and both a light green colour. Copper can be beaten thin enough to allow light to pass through (about a five hundredths of an inch). Copper is used in alloys such as brass (copper and zinc), bronze (copper and tin), 'copper' coins (copper and tin) and 'silver' coins (copper and nickel).
Copper ore and copper ingots were a significant railway traffic, the West Cornwall Line was originally built to allow transport of copper from the Cornish mines.
The Hafod Copperworks located between the Swansea Canal on one side and a bend in the River Tawe on the other was set up by John Vivian and traded as Messrs. Vivian & Sons Ltd. In its day it was one of the largest and most up to date industrial enterprises in Europe. By the 1840s Vivian & Sons were the largest exporters of finished copper in the UK. This firm operated a string of works in the area including Hafod Phosphate Works, Hafod Foundry, Hafod Forge and the Hafod Isaf (Isha) Nickel & Cobalt Works.
The neighbouring Morfa works was operated by Williams Foster & Co. from 1835 until the 1890s, thereafter by Williams Foster & Co. Ltd and Pascoe Grenfell & Co. Ltd. until 1924. In 1924 the Haford works was absorbed by Morfa, which had become the largest non-ferrous metal smelter in the world by the mid-19th century. British Copper Manufacturers owned the combined works until 1928, when they were taken over by ICI, although the refining of copper had ended around 1924. The site was taken over by Yorkshire Imperial Metals, an amalgamation of I.C.I and Yorkshire Metals in 1957, the two works worked as one until closure in August 1980.
In the 1700s the copper mines at Mixon and Ecton in Staffordshire supported a local copper smelting and manufacturing industry based on Oakmoor on the NSR, close to the Cheadle Coalfield. In the 1830s the works were known as the Cheadle Copper and Brass Company, by the 1850s most of the ore came from Wales and Scotland, by this time Patten & Co had an extensive brass and copper works at Oakamoor (where they smelted ingots of copper and brass, and manufactured bars, sheets, rollers, wire, etc.) The calamine (Zinc oxide) for the brass came from mines in Derbyshire. Another firm doing similar work in the 1850s was Keys & Sons at their Brass & Copper Works at Brookhouses.
Thos Bolton & Sons copper works on the NSR Churnet Valley line operated a number of one plank wagons (built to a standard NSR design) for transporting copper ingots. The Foxfield Railway is currently (2007) restoring one of this companies 10 ton 1 plank open wagons (No 15) built in 1916. These were used to transport copper ingots between their works at Oakamoor and Kingsley & Froghall until the 1960s, after which they saw continued service as internal user wagons at the works. Most were scrapped in about 1963. I believe they spent their entire life in light grey with black ironwork, the sketch below is based on a photograph of the as-built wagon on the Foxfield Railway website.
Fig ___ Thos Bolton & Sons copper ingot wagon
In the BR era 12 foot wheelbase shock absorbing wagons with permanently attached nylon hoods (coded Shochood) were used for copper ingot traffic, for an illustration and a description of modelling this wagon in N see also 'Goods Rolling Stock Design - The Body' and scroll down to shock absorbing wagons.
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Tin
Chemists call tin by its Latin name Stannum which gives its chemical symbol Sn. Tin is usually mined in the form of 'tinstone' or Cassiterite, the ore is almost always stained with iron and may be yellow, reddish brown or even black.
The name Cassiterite comes from the Greek word for tin, in the Bronze Age Britain was known as the 'Cassiterides' or 'tin islands'. In Cornwall there were copper deposits but these lodes formerd near vertical seams, whilst mining these they found tin and as the copper ran out they switched to tin mining. Up to about 1860 Cornwall was the worlds largest producer of tin (in Victorian times about a third of all the tin used in Europe was produced in Devon and the Taymar valley), but by the 1960's only two Cornish mines remained; South Crofty at Cambourne and Geevor at St Just (near St.Ives), the ore from both was shipped to the Williams Harvey works at Bootle in Lancashire (who traded as 'Mellanear') for smelting. These two mines produced only about a thousand tons of tin a year and we imported a further twenty five thousand tons a year to support the tin-plate industry in South Wales. The last Cornish tin mine at Geevor ceased operating in 1990 and is now a heritage museum. The deep Cornish mines were early adopters of steam power to pump water out of the workings.
Fig ___ 'Cornish' pump house
The Poldark Mine & Heritage Complex, Wendron, Helston TR13 0ER (Tel: 01326 573173) includes an eighteenth century tin mine along with an associated museum XXX contact for more info XXX. The Tolgus Tin museum in Cornwall has the largest collection of working tin streaming machinery in the country. In the season there are about 13 pieces of plant operating at the same time. There is a superb model railway layout called Wheal Louise, built by XXX it depicts a Cornish tin mine in the nineteenth century. This layout has featured in Railway Modeller Magazine (XXX dates) and is worth studying for anyone contemplating something on similar lines. Tin was also mined on Dartmoor. The major use for tin is of course tin plating iron or steel.
Tin Smelting
Tin smelting was much simpler than for copper, requiring less fuel, and a lot of tin mines smelted the tin at nearby works. The end product, 'white tin' in the form of ingots, was less bulky and hence cheaper to ship to the tin plate works of South Wales than the ore. At the time of World War One there were fifteen tin smelters operating in the UK, six or so in Cornwall, two in Glamorganshire, two in Bootle near Liverpool and one in Bristol.
Tin ore (cassiterite) is crushed, washed and roasted in a reverbatory furnace to remove impurities such as arsenic and sulphur. The calcined ore is pulled from the furnace and allowed to cool on the floor, then it is barrowed to the smelting furnace where it is mixed with fine ground anthracite coal and lime. These furnaces are also reverbatoryand produce a fairly pure metal. The molten tin is tapped off into an iron 'kettle', the slag from the furnace is further refined in another furnace to produce low grade tin, the residual slag was then dumped.
This is then poured into a sloped surface where it runs through a series of channels in a bed of sand in which the metal runs down leaving impurities behind. At this stage the liquid metal put into big. heated, iron pots called 'poling pots' and stirred with green wood poles the moisture in which causes violent boiling bringing the impurities to the surface where they can be skimmed off.
A typical tin smelting works might offer three grades of tin the best being 'Bell' tin, guaranteed to contain 99.90% of tin, and often containing up to 99.95%. The slightly cleaper 'Extra' tin, containing 98% of tin and about 1%
each of antimony and lead, with traces of copper and iron. The low value 'R. B.' tin, containing 95% of tin, with varying amounts of impurities.
Given the description of the process it is unsurprising that the illustrations I have found show wide, low buildings (about the height of a two storey house) with multiple chimneys. The example shown below are (loosely) based on a tin smelter in Cornwall, there was one building of the type shown on the left (which may have been where the ore was first roasted although the chimney is a bit small) and four of the type shown on the right (the actual smelting houses). For a model you would need one of the left hand type and at least two of the right hand type, although the latter could be reduced in width by about a third for modelling purposes.
Fig ___ Tin smelting works buildings
The ingots I have seen were all slightly odd in that they have a raised section in the centre on the top side. They were commonly shifted on a sack truck before the introduction of fork lift trucks, they were heavy though so do not overload your little men. The sketch is based on a photo of men moving tin ingots and shows a typical load for a sack truck.
Fig ___ Tin ingots
Tin can be rolled into very thin sheets and although metal foil is nowadays mainly aluminium it is still commonly called tin foil. Tin is too expensive to be used in pure form for food wrapping and up to the 1960's tin and lead either as an alloy or in the form of lead sheet with tin foil pressed to each side was used.
Tin is a useful coating material forms the basis of several alloys. Tin melts at 232 deg c, lower than most other metals. Tin and lead make solder which actually melts at a lower temperature than either of the two ingredients, Woods Metal is a tin lead alloy that melts at only 66 deg C, it is often used for sprinkler systems. Brass and bronze are both alloys of copper involving tin, these are discussed below.
We often use the word 'tin' when speaking of 'tin plate', which is iron or steel sheet plated with tin, the best example being the tin can. To distinguish things that are actually made from tin the term 'block tin' is usually used for pure tin, tinplate for the coated materials (Tinplate is discussed separately).
Notable tin smelting works include Consolidated Tin Smelting Co, set up in the 1890s to combine Thomas Bolitho and Sons, Daubuz and Co and R. R. Mitchell and Co, based in Penzance in Cornwall. The Tamar Tin Smelting Co was operating in the later 19th century and I believe they continued into the 20th century.
By the later 20th century there were only two tin primary smelting works (recovering tin from ore), one in Merseyside (closed in the 1970s) and one in Humberside (closed in the late 1980s). There remained a small secondary smelting works (recovering tin from scrap) in London.
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Nickel
The Deloro Smelting and Refining Co processed nickel at their Birmingham works, this company produced (and still produces) the very hard wearing Stellite Alloys (based on cobalt-chromium alloy and invented in about 1900) used in machine tools and modern firearm barrels. In the early 21st century there was only one nickel smelter in the UK, located at Clyddach in South Wales. This uses the corbonyl process, the nickel rich material is heated in a flow of hydrogen and carbon monoxide (the gasses are recovered and reused). Some nickel is used as a metal but most is used to make alloys (notably stainless steel) and compounds (for electroplating processes).
Magnesium
Magnesium is the eighth most abundant element and constitutes about 2% of the Earth's crust, and it is the third most plentiful element dissolved in seawater. Although magnesium is found in over 60 minerals, only dolomite, magnesite, brucite, carnallite, and olivine are of commercial importance. Magnesium and other magnesium compounds are also produced from seawater. During World War two the UK operated a magnesium from seawater plant in the North East but I believe this plant closed in the 1960s.
In the early 21st century there was a magnesium smelting plant in Manchester, the magnesium produced is passed to foundaries where most is used to make alloys. Magnesium and aluminium alloys are often produced in the same plant.
Antimony
There were several firms advertising themselves as handling 'sulphides', many of these were producing antimony, mainly used for making low friction bearing coatings. Examples include St. Helens Smelting Co
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