noun
definition
Rock or other material that contains valuable or utilitarian materials; primarily a rock containing metals or gems for which it is typically mined and processed.
Examples of ores in a Sentence
Gold, lead, copper and iron ores occur as veins.
Iron ores have been found in most of the states, and are especially abundant in Minas Geraes.
The problem of the profitable treatment of the sulphide ores has been practically solved here.
This has led to the estimation of sugar by means of the polarimeter, and of the calorific power of fuels, and the valuation of ores and metals, of coal-tar dyes, and almost all trade products.
In the blast-furnace all lead ores are successfully smelted.
He wrote Correlation Papers - Archaean and Algonkian (1892), Some Principles Controlling the Deposition of Ores (1901).
Lead ores are smelted in the reverberatory furnace, the ore-hearth, and the blast-furnace.
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.
Ores are smelted raw if the fall of matte (metallic sulphide) does not exceed 5%; otherwise they are subjected to a preliminary oxidizing roast to expel the sulphur, unless they run too high in silver, say 100 oz.
In making up a charge, the ores and fluxes, whose chemical compositions have been determined, are mixed so as to form out of the components, not to be reduced to the metallic or sulphide state, typical slags (silicates of ferrous and calcium oxides, incidentally of aluminium oxide, which have been found to do successful work).
The lead produced in the reverberatory furnace and the ore-hearth is of a higher grade than that produced in the blast-furnace, as the ores treated are purer and richer, and the reducing action is less powerful.
The gold is found in minute particles arid in the richest ores the metal is rarely in visible quantities before treatment.
The resulting compound, nickel carbonyl, which was described to the Chemical Society in 1890, is both formed and decomposed within a very moderate range of temperature, and on this fact he based a successful process for the extraction of nickel from its ores.
Molybdenum occurs in nature chiefly as the minerals molybdenite (MoS 2) and wulfenite (PbMo04), and more rarely as molybdic ochre (Moos) and ilsemannite; it also occurs in many iron ores.
These harbours on the eastern side of Sydney are mainly frequented by cargo boats trading in coal, corn, frozen meat, wool, hides and various ores.
The Bolivian tin ore is treated by first extracting the silver by amalgamation, &c., and afterwards concentrating the residues; there are, however, considerable difficulties in the way of treating the poorer of these very complex ores, and several chemical processes for extracting their metallic contents have been worked out.
In the article on Mineral Deposits the distribution and mode of occurrence of the useful minerals and ores are fully discussed.
In the case of the cheaper and more abundant minerals, such as coal and iron ore, and of large deposits of low-grade ores, the extent and character of the deposit can generally be determined by surface examinations at comparatively small expense.
The subdrift system requires a smaller amount of narrow work in excavating the necessary haulage roads, and is therefore better adapted to hard ores in which such narrow work is expensive.
On the other hand, as in mining ores containing lead, arsenic and mercury, the dust may be poisonous.
The main mineral deposits are the nickel ores, occurring as veins of garnierite, associated with peridotite dikes, in the ancient rocks of the eastern slope of the island.
The island imports wines, spirits, tissues, clothing and ironmongery; and exports ores, nickel, cobalt and chrome (which represent over three-quarters of the total exports in value), preserved meats and hides, coffee, copra and other colonial produce.
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.
Neither mechanical nor magnetic concentration can effect much in the way of separation when, as in many complex ores, carbonates of iron, calcium and magnesium replace the isomorphous zinc carbonate, when some iron sulphide containing less sulphur than pyrites replaces zinc sulphide, and when gold and silver are contained in the zinc ore itself.
Hence only in exceptional circumstances is it possible to utilize a large class of widely distributed ores, carrying from Io to 35 per cent.
The ores of the Joplin district, in the Ozark uplift in the Mississippi Valley, are remarkable in that they are specially adapted to mechanical concentration.
For the desulphurization of zinc blende where it is not intended to collect and save the sulphur there are many mechanical kilns, generally classified as straight-line, horse-shoe, turret and shaft kilns; all of these may be made to do good work on moderately clean ores which do not melt at the temperature of desulphurization.
It is generally recognized that the purest ores produce the purest metal.
Grades of commercial zinc are usually based on selected ores, and brands, when they mean anything, usually mean that the metal is made from certain ores.
Ashcroft patented a process of dealing with complex ores of the well-known Broken Hill type, containing sulphides of silver, lead and zinc, but the system was abandoned after a long trial on a practical scale.
Traces of ancient workings were found in several places, but the ores did not contain gold in paying quantities.
In 1885 the brothers Cowles patented a process for the electrothermal reduction of oxidized ores by exposure to an intense current of electricity when admixed with carbon in a retort.
The gold ores of Peru are usually found in ferruginous quartz.
The dried dung of the llama (taquia) is generally used as fuel, as in pre-Spanish times, for roasting ores, as also a species of grass called ichu (Stipa incana), and a singular woody fungus, called yareta (Azorella umbellifera), found growing on the rocks at elevations exceeding 12,000 ft.
The methods formerly employed in reducing ores were lixiviation and amalgamation with quicksilver, but modern methods are gradually coming into use.
The metal generally occurs as sulphide of mercury (cinnabar), but the ores vary greatly in richness - from 21 to 20%.
Iron ores are found in Piura, the Huaylas valley, Aya, and some other places, but the deposits have not been worked through lack of fuel.
The manufacturing industries of Peru are confined chiefly to the treatment of agricultural and mineral products - the manufacture of sugar and rum from sugar cane, textiles from cotton and wool, wine and spirits from grapes, cigars and cigarettes from tobacco, chocolate from cacao, kerosene and benzine from crude petroleum, cocaine from coca, and refined metals from their ores.
The ores are generally of good quality, and are easy of extraction.
The richest mining districts are those of Cadereyta and Toliman, where there are metallurgical works for the reduction of ores.
Old schists, free from fossils and rich in quartz, overlie it in parallel chains through the whole length of the peninsula, especially in the central and highest ridges, and bear the ores of Chu-goku (the central provinces), principally copper pyrites and magnetic pyrites.
This group extends east of the Enns, and contains the Erzberg (5000 ft.) celebrated for its iron ores.
Lead ores (chiefly argentiferous galena) and building stone are found, and iron ore is distributed over the hilly country.
The exports include copper and silver and their ores, nitrate of soda, borax, guano and other minerals in small quantities.
In the alluvial deposits the associated minerals are chiefly those of great density and hardness, such as platinum, osmiridium and other metals of the platinum group, tinstone, chromic, magnetic and brown iron ores, diamond, ruby and sapphire, zircon, topaz, garnet, &c. which represent the more durable original constituents of the rocks whose distintegration has furnished the detritus.
Of this increase, a considerable part was derived from gold-quartz mining, though much was also obtained as a by-product in the working of the ores of other metals.
In the Knox and Boss mills, which are also employed for the amalgamation of silver ores, the grinding is effected between flat horizontal surfaces instead of conical or curved surfaces as in the previously described forms.
Gold in galena or other lead ores is invariably recovered in the refining or treatment of the lead and silver obtained.
Pyritic ores containing copper are treated by methods analogous to those of the copper smelter.
In Colorado the pyritic ores containing gold and silver in association with copper are smelted in reverberatory furnaces for regulus, which, when desilverized by Ziervogel's method, leaves a residue containing 20 or 30 oz.