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By E. C. Tarpley, H. M. Cooper, R. F. Abernethy

"INTRODUCTION The float-and-sink test 5/6/ is generally the first test used in determining the washing characteristics of coal. The simplest form of the test is that of using one solution of such specific gravity that the test sample is separated into ""float"" and ""sink"" fractions. In practice, however, a series of solutions is used, and the sample is separated into a number of fractions of a definite specific-gravity range. Analyses of a series of fractions of this type are often referred to as the ""specific-gravity analysis,"" and are of great value in the selection, construction, and operation of commercial washing equipment.The test is rather simple to use, provided a number of conditions are recognized and as many as possible held constant, such as:1. In laboratory testing, two types of solution are available -Aqueous solutions of calcium and zinc chlorides.Mixtures of organic liquids such as carbon tetrachloride, benzene, gasoline, bromoform, etc.2. Absorption of the solution by the coal,3. Solvent action of the solution toward the coal.4. Constancy of specific gravity during the test is affected by temperature changes, dilution, and evaporation.5. Personal technique of the test, such as the time the coal is in the liquid, rate of adding the sample to the liquid, stirring, time of draining, etc.6. Moisture content of the coal as tested."

Dec 1, 1947

By John R. Reeves

The principal oil aha.le in Indiana ie known as the New Al'baZ\Y shale. It 11 ot Devonian age, and ia usually correlated with, although not certainly of the 1ame age a,, the Antrim shale of northern Michiga.. the Ohio shale of Ohio, and the Chattanooga shale ot Kentucky. Termescae • a."ld Georgia. The nqtmal thickneaa of the formation 1n Indiana 1e a.bout 100 faet, ltbough 1n the region of its out­ cro;l the tall th!::kne,111 io rarely exposed because cf the general d:.p of the strata, which is 11 about 30 feet per mile to the west. With the exception ot thin local pha1e1, the entire thickness is oil shale,

Aug 1, 1922

By S. M. S. Azghdi, K. Barani

The effect of microwave treatment on the surface roughness and wettability of chalcopyrite (CuFeS2 ) and on the chemical composition of its surface was studied. The microwave source was a conventional multimodal oven with frequency of 2.45 GHz and maximum power of 900 W. Pure chalcopyrite specimens and purified chalcopyrite concentrate were used in this study. Analysis using atomic force microscopy showed a decrease in the surface roughness of the chalcopyrite after microwave radiation. This decrease may be due to oxidation of the surface and formation of iron oxide. Moreover, the surface wettability of the chalcopyrite mineral increased with increasing duration of microwave radiation, which was in good agreement with the micro-flotation mass recovery results. The increased wettability of the surface may be attributed to the decreased surface roughness by microwave radiation. Analysis using scanning electron microscope/energy-dispersive X-ray spectroscopy indicate that after microwave radiation, the contents of sulfur and iron increased whereas that of copper decreased on the surface of the chalcopyrite, significantly changing the average atomic number of the chalcopyrite surface.

By Carroll Forbes

INTRODUCTION MANY different shapes of drill bits are in use with hammer drills, but little definite information is available whereby to judge which one of these shapes is the best. The following investigation was undertaken in order to determine what effect, if any, the shape of the cutting edge has on the cutting speed and wearing qualities of drill bits. The bits tested were those in common use, namely, the 4-point or cross bit, the 6-point bit, the Z bit and the "Carr" bit. The rock in which the tests were made was the red granite from southeast Missouri. It is a coarse crystalline granite containing an unusually large amount of quartz and is extremely hard, and on account of its uniform texture is admirably adapted to this work. While tests in other rocks might show somewhat different results, nevertheless it is the opinion of the authors that the relative cutting quality inherent in the shape of the bits would be the same in all rocks. Other qualities, such as mudding freely, freedom from fitchering, etc., might make one bit more desirable than another in softer rocks. DESCRIPTION OF BITS TESTED The 4-point bits were the usual shaped bits commonly made on the Leyner sharpener with 14° taper on the wings and a 90° angle between cutting edges. Some tests were run at 85 lb. pressure with a 4-point bit made with a 5° taper on the wings. This was made by using the Carr bit die. The 6-point bits were the usual shaped hits made on, the Leyner sharpener. The Carr bits were made with a 5° taper and an angle of 100° between cutting edges.

Jan 8, 1917

By C. D. Kaeding

IN the summer of 1937, the Algoma Steel Corporation, Limited, decided to embark on the full-scale development o their Helen mine and the erection of plants to produce commercial iron sinter from its ores at a rate ? of fifteen hundred tons per day. The Helen deposit has long been known as one of the largest bodies of non-commercial iron ore in Canada, consisting almost entirely of siderite with a band of pyrite along the north wall and some lenticular inclusions of pyrite throughout the mass. It originally contained a nominal amount of hematite (2,800,000 tons), localized at the western end of the ore-body, but this was mined out during the years 1900 to 1918. For details of the:-geology of the Helen range and of the surrounding district, the reader is referred to Memoir 147, Michipicoten Iron Ranges, Geological Survey of Canada, 1926 (1). The siderite mass was explored by diamond drilling in 1917 and the portion so drilled was estimated to contain 67 million tons of siderite averaging 36.0 per cent Fe, 3.2 per cent S, and 8.2 per cent SiO,, without establishing its ultimate depth or extent. The variation in the sulphur content shown by drilling was from 1.5 per cent in 72 per cent of the tonnage, to 7.2 percent in the remaining 28 percent. The pyritic ore aver-aged about 38 percent iron, but otherwise its composition was substantially the same as that of the siderite mass.

Jan 1, 1940

By I. Bock

Selective Blast Mining (SBM) makes use of milli-second sequential blasting technology to separate the valuable reef material from waste rock in the blasting operation at stope faces in the mining of tabular ore bodies such as exist in the gold and platinum mines in South Africa. The waste rock is cast blast to the back of the stoping area, and the reef material is fractured and deposited close to the stope face. Only the reef material is transported to the surface. A simplified economic model is presented to evaluate the economic benefits of SBM. Although premature, in that adequate experimental demonstration of the validity of the model has not yet been possible, the model is presented since it indicates substantial benefits in the case of narrow reef gold mines. It is suggested that many marginal mines should seriously consider SBM. Benefits can also be realised in platinum mines, but a lot more experimental work is necessary to establish cost parameters more reliably. Some practical experience in the use of SBM in the mining of the UG2 reef is presented.

Jan 1, 1998

By Alexandre José Ramos Valentim, Valéria da Silva Guandelini, Fausto Kunioshi

Em um mercado cada vez mais competitivo, garantir serviços com qualidade em ambientes mais produtivos e de custos reduzidos são valores fundamentais para aumentar a eficiência das organizações. Baseada no modelo de gestão de centro de serviços compartilhados, a Diretoria de Suprimentos da Companhia Siderúrgica Nacional criou o BackOffice como uma das formas de dar foco ao core business e tornar estes valores sustentáveis. Este artigo tem como objetivo apresentar a metodologia utilizada para o planejamento, implementação e aprimoramento da área e compartilhar os ganhos de qualidade, performance e custos com a reorganização e padronização de processos que estavam fragmentados e sendo executados em diferentes departamentos.

Oct 1, 2019

Since 2001, the Hybrid Stress Blast Model (HSBM) project members have developed a software suite to model the complete blasting process from non-ideal detonation to muck pile formation. To preserve the physics and improve solution time, the breakage engine uses a combination of analytical models and 2D axisym-metric finite differences to model near-field crushing, coupled to 3D discrete lattice fracturing and distinct element numerical methods to model throw and muck pile development. The model has been validated by comparison with laboratory and field tests in kimberlite. Multiple blasthole simulations are used to demonstrate how changes to blasting parameters can influence downstream efficiencies. Case studies of wall control blasting show that the presplit design must balance the two opposing effects of increased damage with increased charge and decreasing attenuation of the seismic waves with decreasing charge. Modelling of decoupled explosives needs further development. Reducing the charge towards the back of the trim blast results in a much more significant decrease in back damage than altering the timing. The model demonstrates how separation along the weaker planes in a jointed rock can coarsen the fragmentation, leading to inefficient beneficiation, and extends the damage to a distance of at least twice the burden behind from the blasthole, severely compromising the wall stability.

Jan 1, 2012

The author reviews design evaluation theory and existing optinustion tools and then describes how these have guided recent developments in Whittle Programming's strategic mine design package: Four-X. A new package - Reserve Estimator is also d

Jan 1, 1998

By J. G. Peacey, G. Csicsovszki

The target of this study was to clarify the role of lead on the dissolution of gold in the (NH4)2S2O3-Cu leaching system via chronopotentiometry, linear sweep voltammetry and chronoamperometry. It was found that the dissolution of gold was significantly increased with lead concentration up to 10 mg/1 Pb in the system of 0.1 M (NH4)2S2O3 and 50 mg/1 Cu. \/oltammograms suggested that the anodic dissolution of gold was virtually independent of lead concentration in the range of 1-10 mg/1 in 0.1 M (NH4)2S2O3 solution while in solutions containing copper as well, addition of lead increased the anodic dissolution of gold.

Jan 1, 2011

By B. M. Satish

The aim of the present work is to study the effect of annealing on the vibration damping capacity of high-chromium (16%) ferromagnetic steel. The alloys were prepared from raw materials of 99.9% purity melted in a high frequency induction furnace under high vacuum. The samples were heat-treated in vacuum at various temperatures (800 to 1200°C) for 1 hour followed by slow cooling (120°C/h). The inverted torsional pendulum method was used to evaluate the vibration damping capacity. The results indicated that the vibration damping capacity of the alloys is influenced by annealing and there exists a critical annealing temperature after 1000°C. The damping capacity increases quickly below the critical temperature since the magnetic domains move more easily.

Jan 1, 2009

By A. C. Dorenfeld

Ores of the Mammoth mining district, some 45 miles northeast of Tucson, Arizona, are treated by Mammoth-St. Anthony, Ltd. The ores now treated come from a complex system of veins and faults, comprising three mines, in close proximity: The Mohawk, Mammoth and Collins. The ore treated in the past was oxide ore, which contains economic amounts of gold, silver, lead, molybdenum, and vanadium (as wulfenite and vanadanite). The lead-zinc sulphide ore has never been treated before. The Ore The sulphide ore contains galena, sphalerite, marmatite, pyrite and some chal-copyrite, covellite, chalcocite and bornite, as well as small amounts of gold and silver. The value of the ore is principally in the lead and zinc content. The lead-zinc sulphides are substantially liberated at a minus 65-mesh grind. However, a large part of the chalcopyrite and other copper minerals is not freed, but remains as pin points on the sphalerite. Economically, the copper is unimportant. The gangue is a rhyolite granite, with very little limestone. There is no molybdenum or vanadikm in the sulphide ore. History of Sulphide Treatment Test work on samples of the sulphide ore was conducted by several equipment companies, the Arizona Bureau of Mines and the company's laboratory. Results of this test work indicated that for some reason, which at the time could not be explained, recoveries would be only about 65 per cent lead and 50 per cent zinc. Notwithstanding this, because of the nation's need for metals, the management built a 150-ton treatment plant. The mill was started in June 1942. During December 1942, using the standard method of treating lead-zinc ore, the monthly results were as shown in Table I. These results were poor. Too much lead was in the zinc concentrate, and too much zinc in the lead concentrate. It should be noted here. that prior to December attempts were made to depress the sphalerite with large and varied amounts of cyanide, zinc sulphate, and sodium sulphite with poor results.

Jan 1, 1947

By A. C. Dorenfeld

Ores of the Mammoth mining district, some 45 miles northeast of Tucson, Arizona, are treated by Mammoth-St. Anthony, Ltd. The ores now treated come from a complex system of veins and faults, comprising three mines, in close proximity: The Mohawk, Mammoth and Collins. The ore treated in the past was oxide ore, which contains economic amounts of gold, silver, lead, molybdenum, and vanadium (as wulfenite and vanadanite). The lead-zinc sulphide ore has never been treated before. The Ore The sulphide ore contains galena, sphalerite, marmatite, pyrite and some chal-copyrite, covellite, chalcocite and bornite, as well as small amounts of gold and silver. The value of the ore is principally in the lead and zinc content. The lead-zinc sulphides are substantially liberated at a minus 65-mesh grind. However, a large part of the chalcopyrite and other copper minerals is not freed, but remains as pin points on the sphalerite. Economically, the copper is unimportant. The gangue is a rhyolite granite, with very little limestone. There is no molybdenum or vanadikm in the sulphide ore. History of Sulphide Treatment Test work on samples of the sulphide ore was conducted by several equipment companies, the Arizona Bureau of Mines and the company's laboratory. Results of this test work indicated that for some reason, which at the time could not be explained, recoveries would be only about 65 per cent lead and 50 per cent zinc. Notwithstanding this, because of the nation's need for metals, the management built a 150-ton treatment plant. The mill was started in June 1942. During December 1942, using the standard method of treating lead-zinc ore, the monthly results were as shown in Table I. These results were poor. Too much lead was in the zinc concentrate, and too much zinc in the lead concentrate. It should be noted here. that prior to December attempts were made to depress the sphalerite with large and varied amounts of cyanide, zinc sulphate, and sodium sulphite with poor results.

Jan 1, 1947

By AUDLEY H. STOW

I. INTRODUCTION. THE general drift of the discussion as to the relative merits of pressure- and exhaust-fans has resulted, if we may judge from the prevailing practice, largely in favor of the latter. The subject has been hitherto treated, however, with special reference to highly gaseous mines, the effect of the form of ventilation upon dust-explosions having been too little considered. Even in mines containing practically no gas, dust-explosions may occur; and if, as I believe, pressure-fans are to be preferred for their effect upon dust, it may be worth while to reopen the debate, and to challenge the advisability of exhaust-ventilation under certain conditions. There are several forms of colliery-ventilation, which may be described as follows: Plain or simple pressure-ventilation, in which the fan acts as a pressure-fan, and the movement of coal is unobstructed at the surface by doors or equivalent devices in drifts or shafts, the traveling and haulage thus being in the return-current. Plain exhaust-ventilation, in which the fan acts as an exhaust-fan, the movement of coal being likewise unobstructed at the surface, and the traveling and haulage being in the intake. Obstructed pressure-ventilation, in which the movement of coal is obstructed at the surface, in order that the traveling and haulage may be in the intake. Obstructed exhaust-ventilation, in which the movement of coal is obstructed at the surface, in order that the traveling and haulage may be in the return. The apparent advantages in running a fan "pressure" during working-hours, and " exhaust" between shifts, seem to justify the recognition of this combination as a standard form of ven-

Feb 1, 1909

By J. J. Moore

The application of plasma technology to process metallurgy is briefly discussed. Experiments involving in-flight reduction of minerals (taconite, chromite, in particular) with a solid-based carbon reductant are described. The resultant metallic and slag product analysis is discussed with respect to thermodynamic and kinetic considerations.

Jan 1, 1985

By T. Hadley, E. Catovic

"Northern Minerals Limited’s (ASX: NTU) flagship project is the Browns Range Rare Earth Project (the Project) located in Western Australia, consisting of a number of deposits with high value, heavy rare earth elements, in particular yttrium, terbium, and dysprosium. The deposits are dominated by xenotime mineralisation, which occurs within hydrothermal silicified and hematitic breccias. The Company delivered an initial JORC compliant resource estimate for the Project at the end of 2012 of 10,500 t of contained total rare earth oxides (TREO), which was increased to 28,084t of contained TREO in October 2013 and further enlarged to 47,997 t of contained TREO in February 2014. Concurrent with the growth of the Project resource base, significant progress has been made in developing the metallurgical process for the beneficiation and extraction of rare earth elements (REE’s) from the xenotime mineralisation. Development of the beneficiation circuit evaluated several process options and selected whole-ore flotation and magnetic separation, followed by flotation (hybrid circuit) as the two preferred flowsheets to pilot, following encouraging results on the bench of 83% and 86% recovery to a 20% TREO mineral concentrate respectively. Several downstream hydrometallurgical extraction flowsheets were evaluated. However, the following two preferred process flowsheets were ultimately selected for further detailed investigation during the prefeasibility study: 1. Sulphation bake, water leach, purification, oxalate precipitation, and/or calcination to produce a mixed RE oxide; 2. Sulphation bake, water leach, phosphate precipitation, caustic conversion, HCl leach, and oxalate precipitation to produce a mixed RE oxalate. Excellent heavy rare earth oxide (HREO) extractions (~ 90%) from beneficiation concentrates were achieved on the bench for both circuits, however flowsheet 1 was ultimately selected as the preferred flowsheet to pilot due to lower capital and operating cost. A mixed rare earth oxalate (42% TREO) or oxide (92% TREO) can be produced with low levels of Th and U of 3 ppm and 6 ppm respectively."

Jan 1, 2014

By E. H. Wells, A. Andreas

New Mexico retained its position as the sixth largest oil-producing state for the year 1937 with a total production of 38,484,630 bbl. This was an increase of 11,680,184 bbl. over the 1936 production of 26,804,446 bbl., or a gain of 43 per cent. The production for Lea County during 1937 was 35,961,056 bbl.; for Eddy County, 2,136,251 bbl.; and for northwestern New Mexico (San Juan and McKinley Counties), 387,323 bbl. The average daily non-marginal well allowable for Lea County on Jan. 1, 1937, was 92 bbl.; at the close of the year it was 67 bbl. The average daily pipe-line runs were less than the allocations of the New Mexico Oil Conservation Commission, but slightly in excess of the state allowables recommended by the United States Bureau of Mines. The average daily production for the year was 105,437 barrels. The total number of completions in the state was 742, of which 638 were oil wells; 19 hydrocarbon gas wells; 5 carbon dioxide gas wells and 80 dry holes. Of the dry holes, 46 were in proven fields. Of these 46 dry holes, 13 were in the Artesia-Grayburg-Jackson-Maljamar area, Eddy County, two in the Getty Extension field, Eddy County, 11 in the Red Mountain field, McKinley County, three in the Rattlesnake field, San Juan County, and nine in the Aztec-Bloomfield area, San Juan County. There were only eight dry holes in the proven fields in Lea County. Southeastern New Mexico Lea County.—The Monument field was the largest producing field in Lea County, with 10,945,788 bbl., closely followed by the Eunice field with 10,927,929 bbl. The Hobbs field, formerly the largest producing field in Lea County, was relegated to third .place, with 7,292,522 barrels. Drjlling during the year closed the gap between the northern part of the Eunice field and the southern part of the Monument field. The wells in this area were relatively small, because of decreased porosity in the lime. The greatest activity in Lea County was in the Monument pool, with 199 completions, 197 being oil wells, one a gas well and one a dry hole.

Jan 1, 1938

By L. M. Demers, D. C. Kuhn

It has been suggested that radicals on the surface of dust particles are key chemical factors in the pathophysiology that results from the occupational inhalation of coal and silica dust. In addition, oxygenated derivatives of arachidonic acid (eicosanoidsJ have been implicated as important biochemical mediator5 of mineral dust-induced lung disease through their role in bronchial and vascular smooth muscle reactivity, inflammation, and fibrosis. Therefore, we assessed eicosanoid production by the rat alveolar macrophage (AM) exposed in vitro to mineral dusts with varying surface chemical characteristics in order to determine if radicals associated with the mineral dust could influence the production of proinflammatory mediators in the lung environment. Primary cultures of rat AM were exposed to freshly fractured or "stale" bituminous coal dust, as well as untreated silica or silica calcined to 500 and 1100°C. Prostaglandin E1 (PGE;V, thromboxane Ai (T}(Ay, and leukotriene 84 (LTB; levels in incubation medium were determined by specific radioimmunoassay. When AM were exposed to freshly fractured coal dust, PGE2 production was markedly increased. In contrast, exposure of AM to "stale" dust significantly reduced PGE1 production. Exposure of AM to freshly fractured coal dust resulted in a significant increase in production by AM, while exposure to stale coal dust did not influence AM TXA1 production. Neither "fresh" nor "stale" coal dust had any effect on LTB4 production. In vitro exposure of AM to untreated silica resulted in a significant increase in TXA1 PGE.,, TXA; and LTB4 production compared with control. However, exposure of AM to silica calcined to 11oo•c resulted in eicosanoid levels that were not significantly different from control. These effects were still apparent 8 wk after calcination of the silica particles. Silica was a more potent activator of AM eicosanoid production than was coal, and amorphous fumed silica was a more potent activator of AM eicosanoid production than was crystalline silica. These findings suggest that radicals associated with respirable coal and silica particles may play a key role in the ability of mineral dust to activate AM eicosanoid production and therefore may be important in the pathophysiological consequences of occupational mineral dust inhalation.

Mar 1, 1992

Os mais importantes processos de redução de minério de ferro em fornos de cuba convivem, com maior ou menor intensidade, o problema de precipitação de carbono no interior de seus reatores. Para melhor conhecer os efeitos dos parâmetros operacionais desses processos sobre as cinéticas simultâneas de redução das pelotas de minério de ferro e de precipitação de carbono, foi definido um programa cooperativo entre a Samarco e o Grupo de Siderurgia da PUC-Rio. O presente trabalho é a parte 1 deste programa, que analisou o comportamento de pelotas RD nas temperaturas de 500, 700 e 900 °C, vazões de 60 e 90 NL/min e pressões de 1,2 e 2,5 atm, quando reagiram com os gases de topo e sopro típicos das regiões superiores (Zona de Redução-ZR) dos fornos de produção de ferro esponja (DRI). O tratamento dos resultados obtidos nos testes programados pelo método estatístico fatorial, permitiu identificar as cinéticas concorrentes e propor um modelo global baseado no principio da superposição. Finalmente, utilizando as curvas “Grau de Reação Global-GR versus tempo”, mostrou correlações plenamente compatíveis com os dados experimentais levantados e plena viabilidade de aplicação a outros processos de produção de ferro primário.

Aug 1, 2018

Aamot, Olav Crone, Chem. Engr., Norsk Elektrokemisk, Kongensgt. 18, Olso. Norway. '29 Abadilla.-Quirico A., Dir., Bureau of Mines Manila, P. I. '38 Abbott, Clarence E., V.P., Charge of Raw Materials, Tennessee Coal, Iron & R.R. Co., 1212 Brown-Marx Bldg., Birmingham, Ala. '04 Abel, Raymond L., Prof., Dept. of Pet. Refin., Univ. of Pittsburgh Pittsburgh, Pa. '29 Abel. Walter D., Cons. Engr 1839 Holmby Ave., W. Los Angeles. Calif. '32 Abele, Louis T R. F. D. 5. Susquehanna Trail, N., York. Pa. '31 Abell, Leo M., Ore Dressing Investigator, School of Mines Adelaide, S. Australia. '31 Abenius. Hakan V., Mine Supt., Bolidens Gruvaktiebolag Boliden, Sweden. '37 Aborn, Robert H., Asst Met., Research Lab., U. S. Steel Corp. Lincoln Highway, Kearny, N. J. '19 Abraham, W. E. V., East India United Service-Club, 16 St. James' Sq., London, S. W. 1, England. '28 Abrams. Charles Jackson 1624 17th St., Denver, Colo. '36 Abstein, Henry T., Engr. & Mgr., Profile-Tamarack Mines Co Yellow Pine, Idaho. '27

Jan 1, 1938