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AS I told you before in the treatise on ores, once these are found (whether they are ores of metals or semiminerals) it is necessary to assay them in order to know what is in them, since the judgment of the sight is not sufficient for recognizing the quantity or even what substance they contain. For this reason, it is necessary to come to assaying and, with the knowledge of experience, to weigh their virtues and to proceed with the work or withdraw from it and its expense; and also through knowledge to make provision for their defects if some evilness harms the ores. For if you should have need of a thing that would help them and should not find it, all that you have done would be lost; and, on the other hand, if you should find that the ores are abundant and rich and easy to smelt, you take courage to continue without respect for anything. Therefore, in the following book I shall tell you first in general how the assay of all the metals should be made. I shall enlarge in particular on silver more than on any of the others since it is more important. Then I shall tell you how the ores should be prepared for smelting and also how blast furnaces and other furnaces for smelting such ores should be constructed, and finally how all elemental mixtures of metals are to be separated one from the other with the ability and power of art, and how they are reduced to their final perfection and fineness according to their species.

Jan 1, 1942

By C. P. McCormack

THE Cuyuna manganiferous iron ores can be a principal source of manganese for the iron and steel industry in the United States, provided metallurgical methods as a whole are adjusted so as to use run-of-mine ore. The use of manganese in steelmaking is growing. Increasing amounts of impurities in raw materials call for more manganese, a constant cheap supply of which is wanted. There are few deposits of ore in the United States carrying over 35 per cent. manganese that can be mined and marketed at a profit in normal times. We are largely dependent on foreign ores. The small domestic deposits should rightly be held in reserve for an emergency, such as a war, when importation might cease. Even the production from lean ores, concentrated it may be, might not carry us through a protracted stringency. The Cuyuna district is, therefore, during normal times capable of supplying a large total of manganese. The ores are iron ores containing 5 to 25 per cent. of manganese with the inverse range of 52 to 28 per cent of iron. The manganese costs no more per unit in the ore than the iron, because cost of mining, largely by open-pit methods, is not affected by the manganese content. The manganese units should, perhaps, command a higher price, but as their value is contingent on metallurgical practice, a higher price may be justified only when a shortage in manganese occurs. Manganiferous iron ores can never entirely supplant straight manganese ores though methods are employed that will permit them to do so partly. For the manufacture of ferromanganese, ores carrying above 42 per cent. manganese are needed. Ores with manganese running between 20 and 42 per cent. are used for making spiegeleisen. But established practice in certain plants, based on the admixture of manganiferous iron ores to straight iron ores has greatly lessened the consumption of high-priced, scarce, manganese alloys with good results.

Jan 2, 1925

The treatment of beach sands in'' the Bunbury/Capel' area for the extraction of ilmenite is a very recent development in the mining industry in'J7estern Australia. Nevertheless since the commencement of production in 1956, ilmenite has become the sixth most important mineral produced. The increasing world recognition of W.A. as a major' Iiroducer of ilmenite is due primarily ' to its low chromic oxide. ; (Cr203 content,, 0,03% to 0.04%, combined with a medium to high grade TiO2 content, 54% - 6 , supported by large reserves, a'. stable government with close access to good shipping facilities.. Ilmenite is produced from-these deposits at low-costs, enabling the industry to compete on world markets despite high rates for sea freights because of the distance from.major markets.

Jan 1, 1964

By W. A. Hoyer, G. A. Lock

Laboratory and field tests have shown that it is feasible to log for copper in a qualitative way using the techniques of neutron activation analysis. Laboratory tests showed that the 0.51 and 1.04 mev gamma rays of 62Cu and 66Cu, respectively, could be diagnostic. However, in the core holes, the detection of copper was limited to 0.3% concentration because of interferences from the 18Si and Al gamma rays. Both stationary and continuous logs were made, but only the stationary data yielded a recognizable copper response. This response consists of a combination of two effects-the direct response from copper at 0.51 mev and an increase in low energy gamma ray absorption due to mineralization. Both low energy chemical (PuBe) and high energy accelerator neutron sources were used for the laboratory and field tests, while the same 2 X 5 in. Nal scintillation detector served for all the tests. Potential improvements in copper detection might be possible with solid state gamma-ray detectors which have better gamma ray resolution but much less detection efficiency. This type of activation logging requires complex equipment and trained personnel to conduct field operations and may find application where coring is difficult or prohibitive.

Jan 1, 1973

By Joseph Singewald

INTRODUCTION FOR a number of years Russia, India and Brazil have outranked .all other countries as producers of manganese ores. During the 5 years immediately preceding the European war, the average annual production of Russia was 844,000, of India 694,000 and of Brazil 200,000 long tons. Since the outbreak of the war there has been a considerable falling off in the Russian and Indian production, particularly in the former, whereas the production of Brazilian ores has been greatly increased, amounting in 1914 to over 250,000 tons and in 1915 to nearly 350,000, with conditions favorable for a still larger production in 1916. Manganese is one of the few industrially important metals that are not produced in the United States in quantity commensurate with our needs, so that we have been compelled to import annually about 300,000 tons, having a value of over $2,000,000, and these ores have been obtained from the three countries mentioned above. Their rank as contributors to our imports of manganese ores was India, Russia, Brazil; and in 1913, Brazil contributed only one-fifth. During the past 2 years Brazil has furnished rapidly increasing quantities to this country, and, with the falling off of imports from India and Russia, has become our principal foreign source. In 1914, Brazil furnished two-fifths of the imports and more than India or Russia, and in 1915 over nine-tenths. The manganese ores of Brazil are consequently of more than usual interest to us at this time.

Jan 10, 1916

By D. S. Nilsson

Small-scale mines are today expected to provide much of the increased production of metals and coal this county demands. But in fact the category of larger mines tends to grow in number and size faster than the category of smaller mines. Larger mines show the highest productivity, the lowest injury frequency, and the lowest costs. Lower cutoff grades can be wed in larger mines. The paper describes how the production level affects the choice between different types of loading, haulage, and hoisting equipment; how the increased production level in a mine results in lower production costs per ton; and how this affects the profitability of mining deposits with various ore grades. The future trend is expected to favor larger and larger operations.

Jan 1, 1983

The major copper orebody at Mount Isa is being extracted at a rate of four million tonnes per year. The method used requires an equivalent rate of back filling with (mainly) cemented fill. There were three major incentives for developing this mining system. The first was the prospect of high ultimate recovery of the orebody. The target is 100 per cent recovery. Also the proposed stoping layout appeared to offer significant advantages in development and production costs. Finally, extensive subsidence above the northern end of the orebody could have disturbed permanent surface installations and jeopardised a possible future open cut. The full implications of this ambitious strategy were not apparent in the early years. Now, after 12 years of production the benefits are being realised and they can be weighed against the costs. Probably the most interesting result which comes from this analysis is the significance of cutoff grades and dilution factors in balancing mining and filling rates.

Jan 1, 1980

By William F. Ward

One often reads of the rich placer gravels in many of the citnoe-trav-elqd rivers of South America. The apparent richness of these gold-bearing gravels impresses the traveler, and in fact he may see batea after batea showing enough colors to figure over a dollar per cubic yard. These workings are called "playas" from the Spanish word playa, meaning shore or beach. Many workings have been reported in tropical rivers, but to my knowledge no dredge has made a success in such deposits. Investigation generally shows that the area of richness is limited and especially that the depth of the rich concentration is hardly ever more than a few inches. The Cauca river in Colombia, South America, is noted for its many rich playas. This river rises near .Popayan in the southern part of Colombia, flows north through a narrow valley between parallel mountain ranges and empties into the Magdalena river near Maganque. , The airline distance between source and mouth of this river is only about 500 miles. The rainfall is large and the lower Cauca appears to be about the size of the Missouri river in the United States. From its mouth up to Valdivia, in the State of Antioqua, it is navigable. Above Valdivia is a narrow gorge, above which the river is again navigable for some distance. The part of the Cauca where the play a panning is most noticeable is from Valdivia down to where the Nechi river enters the Cauca, a distance along the river of about 100 miles. The current in this part is swift, so that the stern-wheel river steamers make the trip with some difficulty. In the course of my work in this section of Colombia I have had the opportunity to make a study of several of these play a workings and will give in detail the conditions observed. The Island"Playa" The richest of the island playas is about 40 miles below Valdivia and a little below the old town of Caceres. The shape of the river and the location of the deposit are shown in Fig. 1, which indicates the condition at low water. The river at this place is about 600 ft. wide and the island about 75 ft. wide by 300 ft. long. The island is made up of coarse pebbles, some of which are as big as a man's head. In times of high water this island is under several feet of water and in a swift current. When the river lowers the current is still fast enough to prevent sand or silt from covering the coarse pebbles.

Jan 1, 1915

By Ritchie IM

The Parker Centre was formally established by the Australian Government's Co-operative Research Centre (CRC) Program in 1992 and is one of over 60 such centres encompassing a wide-range of applied scientific and resource based disciplines. Government funding for the CRC Program is currently around $A140 million per annum and the Parker Centre receives $A1.8 million per annum to support its core research and education activities.

Jan 1, 1997

By Henry M. Howe

MY attention has been drawn within a few days to a series of articles in Volume XVIII of the Engineering and Mining Journal, 1874, by Mr. J. A. Church, in which it is stated, among other

Jan 1, 1875

By William R. Rumbold

When I was in South Africa during the latter part of 1904, there were three known tin-fields, which may be called the Cape Town, the Bushveld, and the Swaziland fields. The Cape Town Tin-Field. This district is situated near Kuils river, 20 miles west of Cape Town, and 5 miles from Kuils River station on the Cape Town & Stellenbosch railway. The deposits are in granite, intrusive in the Malmesbury beds, which are supposed to be of Silurian or Cambrian age. The granite, resisting denudation better than the surrounding shales, has formed low-lying hills, the highest of which, the Bottlelary Berg, is 1,510 ft. above sea-level. The rock consists of quartz, orthoclase feldspar, and biotite mica; tourmaline is also present. The feldspar occurs in large crystals. The rock is generally decomposed on the surface, and the decomposition sometimes extends as deep as 100 ft. This formation—granite intrusive in Silurian shales— extends for many miles to the northeast, but so far as I know the Kuils River deposits are the only ones now known to occur in it, though probably further prospecting will reveal other deposits. This particular discovery was accidental; alluvial tin being found in the course of boring for oil. The Kuils River Deposit. This deposit comprises both lode and alluvial tin. The lode strikes N-S., and dips about 30' E. into the hill. It is 5 ft. wide, and composed of dense white quartz, in which pinkish-gray cassiterite is distributed in large crystals. The vein also contains considerable quantities of wolframite. Fig. 1 is a rough plan of the relative positions of the lode and the alluvial deposit, the latter, as shown, following the course of a stream, while the lode crops out on the hillside ,

Jan 1, 1909

By Heikki Jalkanen

The mineralogical composition and morphology of solidified copper smelting and converting slags are of some interest from slag cleaning (by froth flotation), impurity elimination, and environmental points of view. Properties result from both the state of molten slag before solidification and processes taking place during solidification and cooling. In solidification and cooling, copper and sulfur dissolved in molten slag are .precipitating substantially from the silicate phase. Even in water quenching of slag, dissolved copper is pushed out of the solution in the form of finely divided precipitate. Elements present in the raw materials are distributed in a distinct manner between the solidified slag and non-silicate solidification products. Arsenic, antimony, and tin are strongly accumulated in copper precipitate, but not the other metallic constituents common in copper concentrates. Smelting and converting slags differ remarkably on their mineralogical composition and morphology although resulting principally of same chemical processes. Converter slags are more inhomogenous; they often contain solid particles and copper content is .as a rule higher than in matte smelting slags. The final copper content of converter slags was observed to be in a distinct manner dependent on iron oxide - silica ratio. Slag forming, solidification, and precipitation phenomena are discussed on the basis of mineralogical and morphology analysis of smelter slags and laboratory scale experiments.

Jan 1, 2002

By J. Nell

An overview is given of the matte melting process used for the beneficiation of South African Platinum Group Metal (PGM) ores. Most producers use six-electrode furnaces to melt the concentrate and Pierce Smith converters to oxidize excess iron sulphide from the furnace matte. Concentrates from two reef-types (the so-called Merensky and UG-2 reefs) dominate the feedstock supply. Concentrate from the Merensky reef is low in chromium and do not pose significant melting problems. Concentrates from the UG-2 reef contain much higher levels of chromium, which results in the formation of chromium-rich spinels during melting. This is attributed to the low solubility of chromium in furnace slag under typical operating conditions (an oxygen partial pressure of 10-8-10-9bar at temperatures of 1550°C to 1600°C). During the converting process care is needed to avoid excessively oxidizing conditions, which result in cobalt, nickel and copper losses to the slag. High nickel losses result in the formation ofFe2NiO4(trevorite), which often forms solid solutions with FeCr2O4and Fe3O4. In future, the main challenge in the processing of South African PGM ores will be to cope with ever increasing levels of chromium in the concentrate. A short-term solution to the problem would be to melt the concentrate under slightly reducing conditions to promote the formation of CrO, which is more soluble in the slag than Cr2O3. A longer-term solution to the problem would be to abandon the current matte-smelting process in favour of an alloy-based process, which would offer total flexibility with respect to the amount of chromium that can be tolerated in the feed. Key words: Merensky, UG-2, furnace, slag, matte, converting, spinel, chromium.

Jan 1, 2004

By V. C. Rogers, K. K. Nielson

INTRODUCTION The potential health impact from uranium milling operations is mainly associated with long-term releases of radioactive contaminants from the mill tailings.(1,2) The major mechanisms for mitigating these potential releases focus on increasing the tailings containment with the addition of migration barriers such as thick earthen covers and clay liners. Some limited investigation has also focused on reducing the radionuclide source terms. This alternative approach has some desirable features, but stringent cost requirements are placed upon source removal methods in order for them to be economically favorable. A cost effectiveness evaluation is presented herein, in which costs for containment methods are used to establish maximum cost guidelines for the source removal methods. The 230U decay chain, shown in Figure 1 contains the radioisotopes of major concern, 230Th, 226Ra, 222Rn and its short-lived alpha-emitting daughters, When the uranium is removed in the milling process, these isotopes, which are normally not removed remain in the tailings solids. The general pathways to the environment from uranium mill tailings are depicted in Figure 2. The dominant pathways are radon to the atmosphere and radium and thorium to a groundwater aquifer. The magnitude of the contaminants released into these pathways can be characterized by the following parameters: 1. The 230Th and 226Ra content. 2. The emanating power for radon. The fraction of radon generated that is free to migrate. 3. The leach rates. Source reduction methods seek to reduce the magnitude of any or all of these parameters. In general the dose rates are proportional to the source terms. For radon production the source term is proportional to the product of the radium concentration, R, and the emanating power, E, so that the risk is reduced by the same factor that reduces RE. For example, if the radium content is reduced by 95 percent, but E is increased by a factor of two, then the dose rates are reduced by an order of magnitude. The source term for the groundwater pathway is not as easy to identify. The peak in the radium concentrations in the accessable water body can also

Jan 1, 1981

By T. Negeri

The simultaneous use of two or more families of collectors can sometimes improve one or more key flotation performance indicators, especially if the ore under consideration contains several minerals bearing the same metal. The maximum amount of collectors that can be used is limited by the need to maintain a high concentrate grade and selectivity. Therefore, when more than one collector is required, an experimental design that allows variations of both the proportions and the amounts with respect to other process factors has to be selected to find the optimum dosage. This type of design is known as "process factors in mixture amount experiment". It is a powerful design suitable for discovering the existence and evaluating the magnitude of the interactive effects between various flotation parameters. This paper elaborates the principles on which such a design is based, and demonstrates its usefulness with a case study.

Jan 1, 2003

In June, 1,334 underground construction and tunneling professionals gathered in Toronto, Ontario for the 2007 Rapid Excavation and Tunneling Conference (RETC). This biennial event, sponsored by SME, is one of the global underground construction industry?s major events. And this year?s RETC was the first one that included the new Underground Construction Association. [ ] (UCA) of SME. In addition, the conference?s exhibit attracted 125 equipment and service providers. The next Rapid Excavation and Tunneling Conference is set for June 14-17, 2009 at Caesar?s Palace, Las Vegas, NV.

Jan 1, 2007

By Alberto Ramirez Sauri

El concepto de rentabilidad se relaciona con un sistema de medida de rendimiento expresado en términos de utilidad de una inversión, una actividad económica o negocio. Mientras que la productividad se relaciona con la cantidad de producto extraído con determinados factores de producción y factores. Por ello, el presente texto analiza las tendencias de los diferentes grados de utilidad con el capital invertido, los márgenes con respecto al ingreso y su relación directa con la productividad del sector minero. Así también es necesario que el sector minero uniformice sus criterios contables para poder llegar a obtener indicadores de rentabilidad, productividad y de otro carácter económico, que permita a cada unidad ubicarse con relación al promedio del sector, facilitándole al empresario el conocimiento necesario para optimizar su gestión en beneficio del sector y la economía del país.

Nov 1, 1972

By F. F. Aplan

Pollution control will be of utmost importance in the 1970's. In this area, the mineral process engineer has a special competence to understand and remedy many pollution situations. There is an old adage that goes, "Build a better mouse- trap and the world will beat a path to your door." Would that it were so, but the reality of the situation is such that, just as a supplier must sell his machine, a professional man must sell his competence. It is a sad but true fact that mineral processing engineers have not done a very good job in selling their extensive competence in the control of a broad range of pollution problems. Recently one of our students visited a paper pulp mill where he was shown a foam fractionator used to remove paper pulp fibers from plant discharge waters. "Foam fractionator hell, that's a flotation cell!'' was his comment. Ah so, it would appear that large numbers of technical people consider themselves experts on "foam fractionation" Or is it that we have been very remiss in demonstrating the usefulness of our equipment and processes and our professional competence to solve, these pollution problems?

Jan 1, 1970

By Dharmappa HB, Sivakumar M

This paper is concerned with two case histories of wastewater quality management in underground coal mines in the Illawarra region. The first investigation briefly presents an analysis of mine water discharge having an extremely high concentration of suspended solids and consistently high barium concentrations, averaging, 14.4 mg/I Barium, over the sampling period. A laboratory study of chemical precipitation processes has indicated that about 91% of barium could be removed by using ferric sulphate and lime. On the basis of the information obtained from the environmental audit process an alternative water treatment and reuse system incorporating 51% reduction in the water consumption with 32% less off-site discharge has been suggested (Thomas, 1995).The second case history is concerned with the storm water management at a mine situated in the Illawarra escarpment where only 20% of the wastewater generated in the colliery is discharged off-site. Computer modelling of the storm water system showed that 75% of the clean runoff becomes contaminated through poor management practices and causes the process wastewater treatment system to fail in wet weather. Suggested improvements include relatively simple alteration to the coal wash filtration dams which are expected to reduce the periods of inefficient operation of these dams by 95%. The use of storm water diversion channels and detention basins can reduce the overflow volumes by 70 - 100 % for a ten year ARI (Average Recurrence Interval) storm event (Wingrove 1996).

Jan 1, 1998

By Stephen J. Reynolds

Arizona's geologic history is complex, resulting in a diversity of rock types and earth materials, including those of commercial interest. Regional variations in geologic history gave rise to three geologic provinces and an inequitable distribution of both metallic and nonmetallic mineral wealth. The Colorado Plateau is largely composed of flat-lying Paleozoic and Mesozoic sedimentary rocks and late Cenozoic volcanic fields and sedimentary deposits. Associated resources include gypsum, halite, sylvite, clays, specialty sand, flagstone, volcanic products, and aggregate. The adjacent Transition Zone features a large expanse of Proterozoic rocks, economically important Devonian and Mississippian carbonate rocks, and Tertiary volcanic and sedimentary materials. Nonmetallic resources in this province include facing and dimension stone, aggregate, decomposed granite, chrysotile asbestos, gypsum, clay, barite, fluorspar, zeolites, and limestone used for lime, cement, and railroad ballast. The Basin and Range Province has the most complex geologic history and, therefore, the most diverse assemblage of industrial mineral occurrences. These include halite, gypsum, clay, aggregate, decomposed granite, diatomite, zeolites, perlite, pumice, kyanite, limestone, marble, stone, and others. In addition, young stream deposits yield vast quantities of sand and gravel, Arizona's most economically important nonmetallic mineral commodity.

Jan 1, 1987