The principal industry is the smelting and refining of lead, and the smelting works are among the most interesting sights of the city.
The returns from the copper fields in the state are at present a little over half a million sterling per annum, and would be still greater if it were not for the lack of suitable fuel for smelting purposes, which renders the economical treatment of the ore difficult; the development of the mines is also retarded by the want of easy and cheaper communication with the coast.
In unlimited supply, important deposits of rich iron ores suitable for smelting purposes; and for the manufacture of steel of certain descriptions abundance of manganese, chrome and tungsten ores are available.
In Roman times, and until 1900, however, owing to lack of fuel, the smelting was done on the mainland.
The bulk of the sulphur mines are in Sicily, while the majority of the lead and zinc mines are in Sardinia; much of the lead smelting is done at Pertusola, near Genoa, the company formed for this purpose having acquired many of the Sardinian mines.
The copper industry has greatly declined since the 18th century; whereas then it kept 20 smelting works employed, now one-tenth of that number can hardly be kept going.
Within the town are situated the smelting-works, the mint, and a Government weapon factory.
The mines once produced 3000 tons of metal annually, copper smelting being largely carried on, but have now almost ceased working.
In smelting at once in the same blast-furnace ores of different character, the old use of separate processes of precipitation, roasting and reduction, and general reduction prevailing in the Harz Mountains, Freiberg and other places, to suit local conditions, has been abandoned.
The smelting zone always has a bosh and a contracted tuyere section.
While the furnace is running the crucible and channel remain filled with lead; all the lead reduced to the metallic state in smelting collects in the crucible, and rising in the channel, overflows into the basin, whence it is removed.
The effect of the two processes on the purity of the market lead is clearly shown by the two following analyses by Hampe, which represent lead from Lautenthal in the Harz Mountains, where the Parkes process replaced that of Pattinson, the ores and smelting process remaining practically the same: - It is absolutely necessary for the success of the Parkes process that the zinc and lead should contain only a small amount of impurity.
The latest cupelling furnaces have the general form of a reverberatory copper-smelting furnace.
Ingalls, Lead Smelting and Refining (1906); A.
By W., and there are smelting works at Karlsvik in the vicinity.
The value of the mining (except salt) and smelting production in Hungary amounted in 1900 to £4,500,000, while in 1877 the value was only £I,50o,000.
The number of persons employed in mining and smelting works was (1900 census) 70,476.
Small up to the beginning of the 19th century, Holywell has increasingly prospered, thanks to lime quarries, lead, copper and zinc mines, smelting works, a shot manufactory, copper, brass, iron and zinc works; brewing, tanning and mineral water, flannel and cement works.
The operations in the metallurgy of tin may be enumerated as: (1) mining and dressing, (2) smelting, (3) refining.
Shaft furnace smelting is confined to those parts of the world where charcoal can still be obtained in large quantities at moderate prices.
Copper smelting has been carried on in or near the town since 1584 when the Mines Royal Society set up works at Neath Abbey; the industry attained huge proportions a century later under Sir Humphrey Mackworth, who from 16 9 5 carried on copper and lead smelting at Melincrythan.
The chief industrial establishments are smelting furnaces for cobalt, meat-preserving works at Ouaco, sugar-works and distilleries at Noumea and La Foa, tobacco, oil and soap factories at Noumea.
It is not known to whom the discovery of isolated zinc is due; but we do know that the art of zinc-smelting was practised in England from about 1730.
As ores of zinc are usually shipped before smelting from widely separated places - Sweden, Spain, Algiers, Italy, Greece, Australia and the Rocky Mountains region of North America - it is important that they be separated from their mixtures at the mines.
In this part of the township a copper mine was worked between 1705 and 1745, and smelting and refining works were built in 1721.
The cost derives from the application of huge amounts of energy, intelligence, and technology to obtain and process the raw materials: digging and smelting to create high-grade steel, harvesting and refining and molding to make rubber parts, and so on.