1862 London Exhibition: Catalogue: Class I.: Weardale Iron Co
394. WEARDALE IRON COMPANY, Tudhoe and Tow Law Iron Works, Ferryhill, Durham.
Iron, steel, and their minerals.
[Obtained a First Class Medal at Paris, 1855.]
Specimens of spathose iron ore, brown ore, coke, pig iron, bar iron, boiler-plates, hoops, wire, cast steel, axles, wheel tyres, cranks, etc. etc.
The whole of the specimens of pig, or cast iron, exhibited by the WEARDALE IRON COMPANY, as well as all their specimens of malleable iron and steel, have been produced from the ores of Weardale, a valley of the county of Durham, extending westward from near the city of that name, to the springs which form the sources of the river Wear at the western boundary of the county, where it is separated from Cumberland by the mountain ridge which looks down on Nenthead and Alston Moor.
The geological formation is the carboniferous, or mountain limestone, series, and the space through which the ore is found, in separated veins and masses, extends about fifteen miles from east to west; its average width being, from north to south, about six or seven miles.
The ores are all of the same general nature, consisting of the spathose, or sparry carbonate of iron, sometimes in a highly crystalline condition, and exhibiting distinctly the usual forms of its crystallization, and sometimes more compactly aggregated, and exhibiting those forms less visibly. It is certain that the ores of Weardale have been all deposited in this state of sparry carbonates; but in very many places, where the superjacent and contiguous rocks and soil have been much shattered and dislocated by the passage and intersection of veins or troubles, the carbonic acid has been expelled from the ore, and has been replaced by oxygen through atmospheric access, and the ore has passed into the state of a brown hematite, i, e., into hydrated peroxide of iron. Generally in such cases it has become impoverished by the infiltration of earthy matter suspended in the percolating water, and by being permeated by the altered ore, which, when first altered, is brought into a pasty or semifluid state.
The specimens of highly crystalline and silvery white iron, exhibiting large lamellar plates or planes of great brightness (labelled A) are called "silvery steel pig iron." It is in fact and strictly steel, and steel, too, of great purity; although from its hardness, and also from its tendency to cleave in the direction of the larger plans, rendering it not malleable, it cannot be used as steel.
At the moment when, after reduction from the state of ore to that of metal, it first passes into fusion, it is entirely malleable and is good steel, but afterwards changes with great rapidity, the greater in proportion to the degree of heat, and passes into the state of the specimens exhibited.
The ores are smelted at Tow Law, in Weardale, with coke made from the coal found there, which is of great purity, and this silvery steel pig iron is produced from the finest of these crystallized ores, selected for the purpose, specimens of which are exhibited and labelled correspondingly with the letter A.
This peculiar variety of iron is the same as is made and used in Germany from the same kind of ore, and known there by the name of spiegel eisen, or specular iron, and the chemical analysis, which will be found below, of one of these English specimens, and of the German one, which will be found along with them, and which is labelled for the purpose of distinction B (but which is stated to have been smelted not with coke, but with charcoal), will serve to show that they are, notwithstanding, as identical in composition, as they obviously are in their external characters.
The other specimens of cast iron exhibited, are of grey pig iron, as generally made from the same Weardale ore, but taken as it comes from the mine, or of its ordinary or average quality. It consists, however, chiefly of a more compact or less highly crystalline variety of the sparry carbonate, of which some specimens are shown and labelled C, the same letter being also used to mark these specimens of iron. These specimens comprise the qualities usually distinguished as No. 1 and No. 3, as used for foundry purposes, i. e., for re-melting and re-casting into various forms of what are called cast metal goods. They also comprise the quality called No. 4; which is also partially used for the same purpose, but which is chiefly employed in the "puddling" process; i. e., for conversion into malleable iron and steel. For these purposes it is not quite equal, but yet not greatly inferior to the silvery steel pig iron; and the whole of the iron produced from these Weardale ores possesses a peculiar fitness for making steel of a superior quality, in a degree very far beyond the produce of ores, of much greater richness, as regards the quantity of iron they contain. In fact they may be called, and considered as distinctively steel ores.
A portion of the brown hematite produced as before described, is also used in mixture with the sparry carbonates; and specimens thereof, labelled respectively with the letters D and E, exhibit the variable degree, and the manner, in which that ore is mingled with the rocks and earths, adjacent to the place of its deposit.
The specimens of bar iron marked "Tudhoe" are made from the produce of the brown ores. The tensile strength is about 25 tons per square inch. The bar iron and boiler plates marked "Weardale" made from pure spathose pig iron—are remarkable for ductility, and possess a tensile strength of about 28 tons per square inch.
The specimens of cast steel are made from Weardale spathose iron by the atmospheric process.
(Copy) "Assay Office and Laboratories, 29 Gt. St. Helens, Bishopsgate Street Within, London, 25th Nov., 1861.
"Sample marked No. 2, Weardale 'Spiegel Eisen' sent by Charles Attwood Esq., contains:-
- Iron: 99.510
- Manganese: none
- Carbon: 0.065
- Sulphur: none
- Phosphorus: a trace
- Silica: 0.140
- Loss: 0.285
- Total: 100
(Signed) " MITCHELL and RICKARD."
(Copy) "Assay Office and Laboratories, 29 Gt. St. Helens, Bishopsgate Street Within. London 25th Nov., 1861.
"Sample marked No. 1, German 'Spiegel Eisen' sent by Charles Attwood Esq., contains:-
- Iron: 98.655
- Manganese: none
- Carbon: 0.210
- Sulphur: a trace
- Phosphorus: a trace
- Silica: 1.062
- Loss: 0.073
- Total: 100
(Signed) "MITCHELL and RICKARD."