Search Documents

By Charles Prasky

This report describes and appraises recent progress in the development of a differential sulfatizing process for recovering a ferrograde manganese oxide from low-grade manganiferous ferruginous materials in the Cuyuna range. Individual process steps were carried out successfully using a 20-inch-diameter shaft for continuous countercurrent sulfatization of the manganese, a multiple-compartment rotary drum for leaching the water-soluble manganese sulfate, a submerged-combustion evaporator for the recovery of monohydrate crystals of manganese sulfate, and a shaft furnace for the thermal decomposition of sulfate crystals for production of a ferrograde manganese oxide and a sulfur dioxide gas suitable for sulfatization of fresh are. Of the two general kinds of Cuyuna manganiferous materials--the carbonate slates and the oxidized ores--only the slates were studied at pilot scale.

Jan 1, 1963

Sampling protocols and metallurgical flow sheets should be designed to suit the style of mineralisation in question. In support, the a priori need for evaluation programs is the characterisation of the mineralisation type(s) and domain definition. The proportion and size of gold particles has a direct impact on the effectiveness of sampling protocols and metallurgical processes employed. Within the coarse- to-fi ne gold spectrum, the samplability of a deposit ranges from relatively simple for fine-grained disseminated particles, through to difficult for coarse gold mineralisation. Conversely, metallurgical processing may be relatively simple for coarse gold ore and more difficult for very fi ne gold ores. Most deposits contain a proportion of both particle size types. The nature of mineralisation, mineralogy and associated gold particle sizing can only be determined by preliminary sampling to facilitate testing. Mineralogical studies, focussing on ore mineralogy and gold particle deportment, size and distribution are required as part of wider paragenetic and geometallurgical investigations. This paper discusses key issues and presents a methodology for the determination of gold particle size in coarse gravity-gold ores to support sampling optimisation and which also contributes to metallurgical characterisation.

Aug 1, 2010

By Robert D. Thomson

Sheet mica is an important material in the manufacture of electronic and electrical equipment. Large quantities are consumed each year as an essential component in generators, transformers, radios, television sets, radar, electric lighting equipment, and electrical appliances. The nature, structural imperfections, and impurities determine to a great degree the usefulness of sheet mica. Proper processing and classification add greatly to its market value. This report is designed to assist producers in understanding the complexities of marketing muscovite sheet mica. ACKNOWLEDGMENTS Special acknowledgment is due S. A. Montague, of Spruce Pine Mica Co. and G. A. Purcell, mica consultant, General Services Administration, for their critical review and many helpful suggestions in the preparation of thin report. Assistance from other industry and Government representatives is acknowledged with thanks.

Jan 1, 1955

By R. O. Dannenberg

The Bureau of Mines conducted laboratory investigations with the objective of developing an alternative process for recovering cobalt and copper from complex sulfide concentrates. Processes currently used depend largely upon precipitation techniques to remove impurities and recover cobalt from sulfate liquors prepared by oxidative pressure leaching of the sulfide concentrates. The Bureau conducted bench-scale research on a process for treating cobaltite concentrates, comprising (1) oxidative pressure leaching, (2) jarosite precipitation followed by H202 oxidation and pH control to remove iron and arsenic, (3) copper solvent extraction with a mixed hydroxyoxime-amine extractant, (4) copper electrowinning from recirculating acidic strip liquor, (5) selective cobalt extraction from copper solvent extraction raffinate with a phosphinic acid extractant, and (6) electrowinning of cobalt from a recirculating weak acid strip liquor. Overall cobalt and copper recoveries were 91.7 and 84.1 pct, respectively. Electrowon products assayed 99.8 pct Co and 99.89 pct Cu.

Jan 1, 1987

By E. H. Henderson

Introduction Stamp-Milling and amalgamation is, perhaps, one of the oldest processes of recovering gold from its ores. Many papers, theses, and textbooks have been written on the subject of stamp-milling practice in general, but, to my knowledge, there have been no publications describing the modern stamp-mill as designed, developed, and operated in Nova Scotia. Although it may be said that the gravity stamp-mill is the most primitive, and perhaps the crudest, crushing machine in existence, it is at the same time the most satisfactory all-round milling and amalgamating device yet contrived. Originating in Saxony, and used in North America first in Virginia and Georgia, the stamp-mill, in a primitive form, later found its way to California and Colorado. Here, it speedily developed from an affair of wood shod with iron, and operated with the crudest gearing, to substantially its present form. Briefly, it consists (see Figure 1) essentially of a series of hammers (the stamps), which fall upon a mixture of ore and water contained in a cast-iron box (the mortar). The resulting crushed ore (the pulp) is splashed out through a screen on the front of the box. For some years after the discovery of gold in Nova Scotia, in 1861, the ? arrastra and Chilean mill were used to recover the gold from the rich ores. The stamp-mill followed, and various types were used, principally the California and Gilpin County types. Then, in 1895, Mr. M. R. O'Shaughnessy, one of our foremost amalgamators, conceived the idea of a new type of stampmill, which has since become standard in Nova Scotia gold mines. This mill, unique in its design and operation, is specially adapted for the most efficient extraction and recovery of gold as it occurs in our Nova Scotian ores. It is commonly known as the Underwater Feed type, as opposed to the usual Overwater or Top Feed type, and it may be rightly termed The Nova Scotia Self-Classifying Stamp Amalgamation Mill. It is conceded by experienced mill-men that it is superior to any other type of mill for recovering the very coarse and granular gold typical of the ores of this Province. The particular installation and practice to be described in this paper is that of the Guysborough Mines, Limited, at Goldenville, Guysborough county. Emphasis will be laid on certain operating innovations of extreme simplicity and high efficiency.

Jan 1, 1935

By H. G. Iverson

The purpose of this investigation was to beneficiate the Talladega gray iron ores by flotation. A component of the problem was the determination of the degree of beneficiation possible by flotation as well as the relative selectivity of certain reagents in promoting flotation of either the iron minerals or the siliceous gangue minerals. The scope of the present investigation involved only the use of small-scale laboratory equipment. Treatment by roasting and magnetic separation was not included in this study, inasmuch as a similar comprehensive investigation was completed and the results were published by the Bureau of Mines in 1927. The results of the work on Talladega iron ores are briefly summarized in this report. In the search for efficient and economic methods of beneficiating low-grade iron ores, the flotation process is among those that are receiving considerable attention. The Talladega ores are of particular interest for a flotation study, because they contain two iron minerals (magnetite and specular hematite) that are somewhat dissimilar in their flotative response.

Jan 1, 1949

By Kenneth Williams

Cargas a granel, incluindo finos de minério de ferro, devem ser embarcadas de acordo com as diretrizes acordadas entre os membros da Organização Marítima Internacional (IMO). Uma medida de segurança crítica é o Limite de Umidade Transportável (TML), exigido para cargas do Grupo A (cargas que têm tendência à liquefação). Diversos acidentes com navios envolvendo finos de minério de ferro da India, cuja causa suspeita-se ser a liquefação da carga, trouxeram à atenção o tema do TML de finos de minério de ferro. Um trabalho extenso de pesquisa foi desenvolvido pelos principais produtores de minério de ferro da Austrália e do Brasil para dar suporte à IMO no desenvolvimento de normas para o embarque desse tipo de material. Com essa finalidade, mineradoras patrocinaram o projeto AMIRA P1097, que foi conduzido pela TUNRA Bulk Solids (TBS) e o Centre for Bulk Solids and Particulate Technology (CBSPT), CSIRO e a Universidade de Auckland, com a gestão do projeto sendo feita pela Creative Process Innovation, a fim de estabelecer uma abordagem modificada de testes de TML específica para finos de minério de ferro. Esse estudo deu suporte aos resultados dos testes e conclusões do Technical Working Group do IMO, que publicou suas conclusões e descobertas em Setembro de 2013.

Aug 16, 2017

By T N. Little

This review paper presents an integrated and practical insight to blasting geology and its importance. This approach involves developing blasting objective up front and implementing geology specific blast designs. The author refers to this approach as ‘starting at both ends’. There are many human-imposed controls on blasting operations, such as: safety, security, legislative, company standards, heritage, and environmental constraints. Thus it is possible for some operators to lose sight of the controls imposed by nature. This paper demonstrates how site geology controls or influences many aspects of the rock breaking processes and how a focus on this aspect has potential to add considerable value to mining operations. It is obvious that mining companies concentrate their efforts on economic/ore geology (good rock geology). However it is the author’s experience that they also concentrate on engineering geology (bad rock geology) only when forced to do so by the ground conditions, but seem to run out of puff before they apply blasting geology (big rock geology). This paper contains five main sections. In the first section, the impact of geological controls on blasthole drilling is briefly discussed in terms of drill selection, penetration rates, bit wear, blasthole stability, blasthole deviation, and health precautions. In the second section the geological controls on aspects of geometric design are reviewed. These include: hazardous minerals, valuable minerals, selection of the blasting techniques, geological structures, blasting direction, and blasting geometry. Section three overlaps with the geometric design section and deals with aspects related to explosives. Topics addressed include selecting the explosive type based on geology, distribution of explosive charge in space and time, explosive performance, and the rock response to explosive loading. In the fourth section, examples are given of the operational complexity needed to implement a blast to cater for difficult bench geologies, environment constraints, past mining (voids) and need for a high degree of quality control. Section five demonstrates geological controls on blast results. Blasting results include the muck pile characteristics, downstream handling and processing, damage to the remaining rock, and blasting emissions.

Nov 8, 2011

By Mokhinabonu Mardonova, Yosoon Choi

Open-source technology for supporting the Industry 4.0 has become the target of academic research in many sectors. This study reviewed the trends of open-source technology, its forms, and some industrial applications. As a case study using open-source hardware and software for the mining industry, this study proposed a low-cost environmental monitoring system for non-metallic underground mines to support mine safety and occupational health issues. The system was developed using open-source hardware, Arduino and 3D printer, to design the monitoring device. An open-source software, MIT App Inventor, was used for developing an Android application for smartphones to enable remote communication with the system. Field experiments were conducted at an underground tunnel and a non-metallic underground mining site to assess the performance of the system in both mobile and static modes, respectively. Although a few limitations related to the precision of the low-cost dust and gas sensors still exist, the findings of the experiments show that the mining industry can benefit from open-source technology deployment when considering cost factors

By V. I. Lakshmanan, R. Roy

"Zinc is the fourth most widely used metal in the world after iron, aluminum and copper. The primary zinc production is through flotation of zinc concentrate, roasting, leaching and electrowinning. Close to 60% of the metal produced is consumed in galvanizing the steel by making a thin layer of zinc coating on the steel surface by hot dip galvanizing. Process Research ORTECH Inc. has developed an efficient energy-saving sustainable technology for the recovery of zinc from secondary sources such as galvanized steel scrap, dross, dusts etc. The process consists of treating the zinc containing scrap in an alkaline solution to remove the zinc and thereby producing a zinc free steel scrap for recycle. The zinc containing leach liquor is subjected to a solvent extraction process to recover value added zinc oxide as the final product. In this paper, important industrial processes for the recycling of zinc including the PRO process will be discussed. BACKGROUNDZinc is the fourth most widely used metal in the world after iron, aluminum and copper. Global refined zinc output increased by 2.7 per cent to 13.16 million tonnes in 2011 and is expected to increase by an additional 2.4 per cent to 13.48 million tonnes in 2012 [1]. The primary zinc production is through flotation of zinc concentrate, roasting, leaching and electrowinning. Close to 60% of the metal produced is consumed in galvanizing steel by making a thin layer of zinc coating on the steel surface by hot dip galvanizing. Other major usages of zinc are in the production of brass and bronze, die casting and zinc-air batteries. The additional demand for zinc could come from its addition to fertilizers to increase crop yield.While the demand for zinc is increasing, many mines are scheduled to close in near future after being depleted of ore. The mines set to close between now and 2015 are Teck Resources’ Red Dog Mine in Alaska, Minmetals’ Century Mine in Australia and Vedanta Resource’s Skorpion Mine in Namibia [1]. The depletion of resources due to continued use and exploitation is becoming a great concern for the zinc industry. As a result, the sustainability of natural resources for continued societal care has become extremely important. Resource conservation and recovery by recycling with minimal environmental impact is a key element for sustainable development. In this paper, important industrial processes for the recycling of zinc including the PRO process are presented."

Jan 1, 2012

By H. C. Fuller

Submerged combustion and inverse solubility methods were investigated as promising alternative means for crystallizing manganese sulfate from solutions produced by leaching manganese ores with either sulfuric acid or sulfur dioxide. Evaporation of water from typical manganese sulfate solutions by sub-merged combustion techniques enabled production of a slurry containing 32 to 39 pct MnSO4.H2O crystals suspended in a saturated solution of manganese sulfate. Such a slurry required further processing by thickening or filtration and drying to produce crystals of MnSO4.H2O. In a second approach, semicontinuous processing of manganese sulfate solu¬tions by thermal crystallization under pressure effected a recovery of 94.5 pct of the MnSO4.H2O as dry free-flowing crystals. Treatment of a solution containing about 100 grams manganese per liter at 189° C, produced a "barren" solution containing only 1.9 grams manganese per liter. Calculations made on comparable manganese sulfate solutions show that the heat requirement of the thermal crystallization method was about one-third to one-fourth that of the submerged combustion method.

Jan 1, 1966

By P. Halsall

Smelters of medium or low grade tin concentrates must recover a high proportion of tin from iron-bearing slags or concentrates; the volatility of tin sulphide makes possible the production of iron-free tin fume. Laboratory work defined conditions which would promote the sulphidisation of tin slags and concentrates melted with them, to result in tin recovery as fume, and a residue of less than 0.5% Sn content, which could be controlled to vary with the value of tin. Subsequently pilot-plant work on 6-tonne and 15-tonne scale led to a commercial plant of 45 tonne. capacity (1962), for melting and fuming primary and secondary low-grade tin materials by submerged combustion. Some factors contributing to the rate of Working expressed in terms of the 'half-life and the amount of work done, the 'half-life-tonne' are studied, leading to the design and operation (1972) of the 100-tonne water-jacketed unit, presently in use, treating a wide range of slags and low tin-content ores and residues.

Jan 1, 1983

"The following articles were produced through funding under Generic Mineral Technology Center for Respirable Dust research. Full articles appear in the proceedings, 3rd Symposium in the Mineral Industries, published in 1991 by the Society for Mining, Metallurgy and Exploration, Inc.Personal Diesel Exhaust Aerosol SamplerV.A. Marple, K.L. Rubow, and Y. TaoParticle Technology, Mechanical Engineering Department, University of Minnesota, Minneapolis, Minnesota(Section ill. Diesel I: Diesel Particulate Measurement, pp. 73-81)Abstract. Techniques are being developed for measuring the mass concentration of respirable diesel exhaust particles found in underground coal mines. Studies have been conducted over the past five years to investigate size selective 18Dlpling techniques to measure the respirable mass concentrations of diesel exhaust and mine dust aerosol particles in underground coal mines. Results from these studies have been used to develop design and performance criteria for a personal diesel exhaust aerosol sampler.Three personal diesel exhaust aerosol samplers have subsequently been designed and evaluated in both laboratory and field settings. These samplers use size selective classifiers for the determination of respirable mass concentrations of mineral dust and diesel exhaust particles. Their designs are based on the premise that diesel exhaust particles are predominantly less than 0.8 µm while mineral dust is greater than 0.8 µm.One design, selected for field evaluation, consists of a 10 mm nylon respirable dust cyclone followed by a 0.8 µm cutpoint impactor and afterfilter. The cyclone removes the nonrespirable particles while the inertial impactor state, collects the mineral dust on an impaction plate and allows the diesel particles to penetrate to an afterfilter. The two sample fractions of the respirable particles ( <0.8 µ.m and >0.8 µm) are gravimetrically analyzed to determine the concentrations of the diesel and mineral dust portions in the respirable coal mine aerosol."

Mar 1, 1992

By Saskia Duyvesteyn

Small ion-exchange resin particles provide faster mass transport than conventional-sized beads. Unfortunately, high pressures are needed to pump solutions through columns containing small resin particles. It is preferable to disperse fine resins in the solution being treated. Screens have been used to separate the resin from the solution, but screens do not retain fines created by attrition of the resin particles. We have developed a separation process based on flotation, which relies on the surface characteristics of the resin, instead of size. The resin is conditioned with a surfactant before dispersing it in the solution to be treated; this increases the hydrophobicity of the resin sufficiently for froth flotation, without introducing surfactant directly into the solution. The surfactant adsorbed on the resin surface does not appear to impair the kinetics of metal ion removal. A flowsheet for an effluent treatment process is proposed; other applications are clearly possible.

Jan 1, 1998

By E. Asselin

Passivation of Fe-Ni-Co alloys during the Caron leach process is thought to result in low cobalt recoveries in ammoniacal ammonium carbonate solutions. A brief review of the available thermochemical data for the (Fe, Ni, Co)-NH3-H2O systems has been undertaken. The stability of the Co(II) and Co(III), Ni(II) and Fe(II) am-mines was examined through the use of speciation and Pourbaix diagrams at 298 and 333 K and at 6 M total ammonia. Increasing the temperature reduces the stability fields of the ammines and generally constrains the thermodynamic window for the leach. The Fe(II) ammines are only thermodynamically stable under reducing conditions. Polarization experiments show that these ammines are unlikely to form if oxygen is present. Fe-Ni-Co alloy passivation may be alleviated by careful management of potential.

Jan 1, 2011

By A. Lopez-Valdivieso

Particle size enlargement processes play an important role in solid/liquid separation, and in beneficiation unit operations. In the latter, not only the size of the formed aggregates but also their surface properties are very important. Oil agglomeration has a special place among such processes: it is a selective process in which hydrophobic particles are agglomerated into hydrophobic agglomerates which can be recovered by flotation. This explains the broad applications of oil-assisted beneficiation processes not only in the beneficiation of fine coal, but also in agglomerate flotation of many different types of ores, and in coal/gold agglomeration.

Jan 1, 2004

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

By E. Asselin

Passivation of Fe-Ni-Co alloys during the Caron leach process is thought to result in low cobalt recoveries in ammoniacal ammonium carbonate solutions. A brief review of the available thermochemical data for the (Fe, Ni, Co)-NH3-H2O systems has been undertaken. The stability of the Co(II) and Co(III), Ni(II) and Fe(II) ammines was examined through the use of speciation and Pourbaix diagrams at 298 and 333 K and at 6 M total ammonia. Increasing the temperature reduces the stability fields of the ammines and generally constrains the thermodynamic window for the leach. The Fe(II) ammines are only thermodynamically stable under reducing conditions. Polarization experiments show that these ammines are unlikely to form if oxygen is present. Fe-Ni-Co alloy passivation may be alleviated by careful management of potential.

Nov 1, 2011

By Hideaki Kitajima, Daisuke Fukuda, Kazuma Moriya, Katsuya Sasaki, Katsuhiko Kaneko

The purpose of this research is to analyze the fracture process and achieve design optimization of a splitting method for concrete and rocks termed the electric discharge impulse crushing method (EDICM). The EDICM utilizes the cartridges being set in boreholes in the splitting target. The cartridge has a thin metal wire and is filled with nitromethane. By applying the electric discharge to the wire in the cartridge, plasma is caused leading to the vaporization of the wire. Then the deflagration of the nitromethane commences, which generates borehole pressure for splitting the target. Although the required splitting time is roughly several hundred micro-seconds and much slower than ordinary blasting, the fracturing still completes in quite short time and understanding the fracture process of opaque and brittle materials such as rock and concrete in this time scale is of academic importance.

Jan 1, 2011

By Oleg G. Tovmachenko

We have studied optical properties of fluorescent nanoparticles. These particles consist of a metal (gold/silver) core, an empty and a dye labelled silica shells. The different dye molecules with moderate quantum yields (about 0.3) has been used. Almost all of types of nanoparticles show fluorescence enhancement. This enhancement is strongly dependent on the degree of the overlap between the surface plasmon band of the metal and the absorption/emission band of the dye molecules. The results are interpreted in terms of competition between local field enhancement and quenching of fluorescence by the metal surface.

Oct 1, 2003