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By Ho-Sang Sohn

The kinetic study on desulfurization of copper matte by gas bubbling was designed under the presumptions of lower FeO activity and of no slag formation, Copper matte with 59% Cu and 22.6% S in weight was oxidized at 1523K by bubbling of Ar + O2 gas through a submerged nozzle. The effects of oxygen partial pressure and flow rate of gas on the oxidation rate of matte were discussed. The desulfurization rate and the evolution rate of SO2 gas of copper matte were significantly influenced by the oxygen partial pressure, but the dependence on gas flow rate was rather complicated. The desulfurization rate and evolution rate of SO2 gas of copper matte were described by the mass transfer rate through the gas film around the rising gas bubbles. Thermodynamic correlation equations between the partial pressure of gaseous species and matte composition were incorporated to the kinetic calculation, The present model shows that the reaction path starts to transiently cross over an isobar line of PSO2 to asymptotically approach to the particular isobar line drawn in a matte composition plane of %S and %O.

Jan 1, 2003

By Rolando Patiño Patroni P

El presente estudio revisa la fisiografía, geología, tipos de metamorfismo, efectos de intemperismo y trabajos de exploración en las minas de Marcona. La zona minera de Marcona está ubicada a 800 m.s.n.m del sur de Lima, Ica, cuyo terreno está comprendido por una plataforma costera, donde la erosión no solo ha producido afloramientos de rocas resistentes, sino también de cuerpos de mineral. Su geología está compuesta de rocas que se subdividen en sedimentarias, volcánicas, ígneas y metamórficas. Asimismo está el granito de San Nicolás, andesita porfirítica, granodiorita y los intrusivos básicos. Su estratigrafía se desarrolla por el aluvión, la formación Pisco, Copara, los volcánicos Nazca, formación Cerritos, Marcona, Complejo Lomas. Entre los efectos del intemperismo está la zona de lixiviación, zona superior de sulfatos, zona inferior de sulfatos y la zona de sulfatos primarios. Finalmente, los trabajos de exploración se realizan a través de los levantamientos magnetométricos (prospección), perforaciones a percusión seca, sondajes diamantinos y las labores subterráneas.

Jul 20, 1959

By Levent Ozdemir

An extensive study involving laboratory testing and computer modeling has been performed to assess the technical and economic feasibility of utilizing the recently developed minidisc cutters on roadheaders for hard rock mining. The results show that heavy duty roadheaders fitted with minidiscs can excavate hard rock formations at acceptable production rates and cutter costs. This paper presents and discusses the results of this study together with the ongoing developmental efforts of this technology, which include laboratory testing of a roadheader cutting drum with minidiscs and full scale field testing of a machine in hard rock

Jan 1, 1995

By Paúl Urruchi

El Departamento de Perforación y Voladura de mina COMARSA, utiliza un nuevo tipo de emulsión a granel, que se sensibiliza in-situ por medio de gasificación al momento mismo de ser bombeada a los taladros. La emulsión del tipo agua en aceite, con buen balance de oxigeno y despliega una alta velocidad y presión de detonación. En este sentido, el presente texto señala las ventajas del uso de la emulsión gasificada como agente de voladura seguro -en tanto reacciona con una solución básica que lo sensibiliza químicamente, justo antes de su carguío a los taladros por medio del camión fabrica, así como agiliza las operaciones de voladura y de minado y reduce los costos de voladura.

Sep 14, 2009

By J. G. Walters

This bulletin presents, in collected and tabluated form, Bureau of Mines and American Gas Association (EM-AGA) carbonization data pertaining to the chemical analysis of tars and the characterization of tars and light oils obtained from U.S. coals.

Jan 1, 1967

By W. P. Yant, G. W. Jones

During the testing of porcelain insulators with a " 60 - cycle flash - over apparatus " , gases are liberated having an odor greatly resembling that of ozone . Since the two main constituents of normal air are nitrogen and oxygen , and high voltages (approximately 90,000 volts ) are used during the tests , the conditions are favorable for the production of ozone or oxides of nitrogen , and perhaps both simultaneously . The presence of these gases is only noticeable during the testing period . They soon disappear after the test is over . No fatalities have ever resulted from these gases at the plant visited nor are there any records of any of the men who worked on the tests being confined to their homes from this cause . New employees sometimes complain of a depressed feeling and shortness of breath , which is most noticeable after leaving work and getting into fresh air , but they som become accustomed to it and no ill effects are noticed . In view of previous work*** which the Bureau of Mines has done on oxides of nitrogen in connection with mine gases and problems in gas analysis , tests were made at the plant of the Westinghouse High Voltage Insulator Company at Derry , Pa . to determine the kind and amount of gases liberated .

Jun 1, 1923

By W. Beckering

IN CHARACTERIZING tars obtained by the low-temperature carbonization or North Dakota lignite, infrared spectra have been an invaluable aid in both qualitative and quantitative examination. Quite early it became evident in the tar-research program of the Bureau of Mines, U.S. Department of the Interior, that the small number of published spectra available for hydroxy aromatics would be inadequate for comparative purposes when dealing with the wide range of compounds present in coal tar; therefore, compiling a catalog of spectra was initiated as a continuing part of the tar program. As these spectra should be valuable to other investigators in this and related fields, they are being presented in this report. This group or spectra (figs. 1-98) represent 97 compounds, largely phenolic materials. The major problem of this project has been the availability of materials for examination. Samples have been obtained from commercial and private laboratories or synthesized at the Bureau of Mines Lignite Experiment Station, Grand Forks, N. Dak.

Jan 1, 1959

By John D. Foulkes

A study to categorize and characterize underground metal/non-metal mining operations from the viewpoint of telecommunication requirements and practices. The objectives were to: ? Gather and analyze data; ? Identify communication requirements; and ? Recommend systems for operational emergency and post-disaster telecommunications.

Jan 1, 1979

By J. Petersen, T. Moyo, D. Maharaj

This study investigates the effect of ammonium thiosulfate on the leaching of gold from the contacts of unpopulated cut electronic printed circuit boards (PCBs). Studies in the literature show ammonium thiosulfate to be a viable option in comparison to the commonly used but hazardous cyanide leaching route. However, the simultaneous dissolution of Cu interferes with the Au leaching reaction, often limiting the extraction to moderate levels. To optimize the system, an ammoniumthiosulfate system containing 0.5M ammonia, 0.5M ammonium thiosulfate, and Cu(II) sulfate at varying concentrations was studied as an alternative hydrometallurgical option for the recovery of gold from PCB. Tests were done with unpopulated standardized model PCBs (cut to 15 x 30mm pieces). Gold extraction of 47.3% was achieved after a 24-hour leaching experiment with a 0.02M copper background concentration. Further experiments focused using different initial background Cu concentrations (0M – 0.1M) to determine its effect on both gold and copper extractions. An initial Cu concentration of 0.045M resulted in the highest gold extraction, with 93.7% extraction after 6 hours of leaching. Further analysis of the data shows that the kinetic rate of gold leaching is correlated in a first-order dependence with the actual copper concentration in the solution, which increases with the concomitant dissolution of copper and gold from the PCBs. A lower threshold of 0.017M and an upper threshold of 0.15M copper in solution were determined, in between which gold extraction shows this first-order rate increase. The upper threshold is potentially linked to the onset of copper precipitation, which blinds the metal surfaces, slowing further leaching. The findings of this study suggest that in an industrial recovery operation of gold from waste PCB using the thiosulfate method, copper concentrations need to be carefully monitored, and the process should preferably operate with uncut or coarsely cut untreated boards to minimize exposure to copper circuits.

Dec 11, 2024

By H. E. Elliott, R. S. Busk, A. T. Peters

One of the problems of the fabricator of metals and alloys is the propensity of some composition rarnges toward abnoermal grain growth during certain stages of fabrication. In this respect magnesium alloys are no exception among alloys. Fortunately, convenient foundry control methods have been developed by which the abnormal grain growth possible in certain magnesium-alloy castings can be suppressed. An unusual characteristic of magnesium alloys, however, is that castings of some composition ranges are subject to local grain growth during heat-treatment without the necessity of intentional mechanical stressing of the part prior to heat-treatment. This effect occurs only under certain critical casting conditions, and only in certain alloys of greater than about 8.5 per cent aluminum content, such as C alloy (Mg, 9 per cent A1, 2 Per cent Zn, 0.2 Per cent Mn) and G alloy (Mg, 10 per cent Al, 0.2 per cent Mn). The first observation of this phenomenon in cast magnesium alloys occasioned much surprise, since it is not observed in other meta1s- Jeffries and Archer1 have stated that "the grain size of cast metals, provided they have not been plastically deformed, cannot be changed by heating below the melting point." The study of the conditions leading to abnormal grain growth in cast magnesium alloys, and of the mechanism of this phenomenon, has led to some very interesting observations. Perhaps the most significant of these was the observation that stresses originating from cooling contraction in magnesium-alloy castings are the only stresses necessary, under certain conditions, to cause local recrystallization and subsequent grain growth in the casting during heat-treatment. Before recent developments, this phenomenon of abnormal local grain growth Was a definite problem in the production foundry on C alloy sand castings. Illustrated (Fig. I) is a picture of a casting scrapped because of this defect. A mottled effect is produced in coarse-grained areas by suitable etching solutions. The properties of metal in the affected area are much impaired by such grain coarsening. Ultimate tensile strengths of half the normal value have been measured in metal of this nature. In this paper are described the techniques that have been developed by The DOW Chemical Co. for studying, and in large measure solving, this production problem. Also discussed are studies of the mechanism by which excessive grain coarsening occurs, and the fundamental conditions that produce this effect. The abnormal grain growth discussed in this paper will be referred to as "germinasium since this term has been definedl as any process leading to an abnormally coarse grain size. This paper deals only with abnormal local grain growth that may occur during the solution heat-treatment of certain magnesium-alloy castings, as dis-

Jan 1, 1945

By W. A. Dixon Edwards

Industrial mineral production in Alberta, worth $468 million in 1997, comes from a dozen types of industrial minerals, mined by about 400 producers. Cement and lime from Paleozoic limestone formations exposed along the Rocky Mountains account for the greatest production value. Sand andgravel is the primary source ofmineral aggregate. Almost two-thirds of this aggregate is consumed in the Edmonton and Calgary regions. Sulphur produced at 48 sour gas processing plants and two oil sands plants was valued at $84.8 million in 1997 and accounted for 80% ofCanadian sulphur production. Four companies solution mine the Elk Point salt beds to produce chlor-alkali chemicals, industrial salt and sodium chlorate. Natural brine is also produced as a dust control product. Al $22 million, peat moss is a major industrial mineral product in Alberta. Other minerals with noteworthy production include shale, stone, silica and ammolite. The commodities with the greatest development potential are diamond, silica and oil sands tailings by-product minerals.

Jan 1, 2001

By H. Polat, Q. Hu, S. Chander

"The collection efficiency of dust particles was determined in a laboratory dust chamber equipped with a water spray. Measurements were made in the presence of selected nonionic, cationic and anionic surfactants. For the nonionic and the anionic reagents, efficiency was maximum in a narrow range of concentration. The surfactant concentration corresponding to high collection efficiency was usually much below the commonly used concentration of l "", however. In comparison, much higher collection efficiency was observed for a cationic surfactant at extremely low concentrations. For delineating the mechanism of capture of dust particles, surface tension and contact angle results were used to obtain a correlation between the work of adhesion and the efficiency of collection. Such a correlation was reasonable for the nonionic surfactants but not for charged surfactants. In the latter case, electrostatic interactions between charged droplets and particles were more important, especially for the cationic reagent. INTRODUCTIONSeveral methods are used to control dust in mines. These include: ventilation, foam, scrubbers and sprays. This article is concerned with improving the effectiveness of water sprays, which are widely used to remove dust particles during continuous mining, by adding small quantities of surfactants. Water sprays produce small droplets which act as collectors of dust particles suspended in air. Sprays directed at the actual source of dust have the additional property of wetting the coal before the ·particles become airborne (Hamilton, 1974). Wetting agents, also called surfactants, arc known to play an important role in many applications where dust is a problem. However, conflicting reports exist in the literature with regard to the effectiveness of surfactants in water sprays (for a review, see Chander et al., 1988). In spite of the conflicting reports, the use of surfactants for dust control has increased over the years. In a recent study by the Bureau of Mines, a 27'6 reduction in respirable dust levels was observed in a mine test when surfactants were added to sprays (Foley, 1991)."

Mar 1, 1992

By José Fernández Dávila Borja

El presente texto señala la eficacia del uso de la fluorita como reactivo de concentración por flotación desarrollado en la mina Canaria de Ayacucho, Pozos ricos, Mansita y San Agustin, donde el fluor como elemento más electro negativo del grupo de los halógenos, ataca a todos los metales excepto al oro y al platino, posilbilitando la limpieza de superficie de los minerales, así como el uso del bario, metal alcalino-térreo, que en su forma de Baritina o sulfato de Bario ha sido utilizado en la "prueba de descarte", concluyendo que la frecuencia del comportamiento de la fluorita, prueba la influencia positiva de esta en la flotación de los valores metálicos.

Nov 20, 1978

By S. J. Thomas, P. A. Lilly, J. A. L. Napier

An industry research project has been established to examine the issue of rock mass failure in large open pit slopes. The approach began with numerically modelling failure at the laboratory scale with a displacement discontinuity program. The interim results from the program suggest the output failure mode is dependent upon the input parameter cohesion weakening. Es wurde ein Forschungsproject mit unterstützung von Bergbauindustrie bearbeitet. Die Zielsetzung der vorliegenden Arbeit war die Analysierung des Böschungsgefähr im größen Festgesteinstagebauen. Das Verfahren besteht aus der numerischer Modelierung mit Ansatz einen sonderen Rechnerprogram. Die erste Ergebnis zeigt, daß die Aufgabe am Angabendaten (cohesion) abhängig sein wird. Un project de recherche industriel fût conduit avec le but d’examiner les éboulements de roche dans les mines a ciel ouvert. La premiere étape a été de modelliser numériquement les éboulements dans un laboratoire en utilisant un programme de déplacement discontinu. Les resultants préliminaires du programme indiquent que la prédiction des ébouliements est directement reliée à la magnitude de la cohesion.

Jan 1, 2003

By S. Mukusha

Electronic spreadsheets are the most common and readily available software applications for analyzing and modeling quantitative problems. Spreadsheets can offer a vast array of opportunities for the analysis and modeling exercises encountered in the field of geomechanics. This study explores the potential for using spreadsheets of in the practice geomechanical engineering. The study also examines some of the barriers to widespread use of spreadsheets. Best practices and guidelines for overcoming potential pitfalls are discussed and highlighted through a case study.

Jan 1, 2000

Once applied, EarthZyme reduces the tendency for a road to exhibit common maintenance issues: wash-boarding, rutting, heaving, potholing and dust.

Aug 1, 2013

By J. M. Demarthe

MINEMET RECHERCHE (IMETAL Group, formerly Le Nickel-Penarroya-Mokta) has studied on a laboratory scale and patented a new process to recover metal values -copper- from sulphide ores and concentrates. It combines a cupric leaching, solvent extraction and copper sulphate electrowinning according to the main following steps - A direct and selective leaching of copper sulphide ores or concentrates at atmospheric pressure with cupric chloride to form cuprous and ferrous chlorides and elemental sulphur. Pyrite remains in the sulphur residue. - The leach solution is separated into two parts -In the first one, air is injected to precipitate iron as goethite. The oxidation step can be easily realized at atmospheric pressure by maintaining an excess of cuprous and-ferrous chlorides in the liquor. Copper is extracted from the second part as cupric ion by an LIX reagent. Direct injection or air in the mixing chamber maintains good extraction conditions, so that only one mixer settler is required. - Iron, in the form of ferrous ion, is not coextracted. - Copper is stripped from the organic phase, transferred into a sulfuric phase and sent to sulphate electrowinning cells, which are now conventional in copper metallurgy. - Only electricity and air are required. After a feasibility study, the next step will be to develop it on a pilot and commercial scale.

Jan 1, 1976

In February 1995, Falconbridge Limited approved the construction of a nickel mining and milling facility on its Raglan property situated in the Nunavik region of northern Quebec, Canada. The construction period successfully terminated with the commissioning and start-up of the plant and concentrator in early-December 1997. The estimated life of the project is 20 years with an annual mining rate of 800 000 tonnes of ore, producing 21 000 tonnes of nickel per year. This paper discusses the subject of æRemote Mining in the Canadian ArcticÆ as it applies to the Raglan mine process and people. During the feasibility stage of the project, many assumptions were made which influenced the design and operating parameters of the facilities and the equipment. Transportation, communication, remote logistics techniques and standard industry practices required to support a æfly-in/fly-outÆ operation were reviewed and either adopted or rejected for use at Raglan. These assumptions were æmade to fitÆ the uniqueness of our planned operation. It was also acknowledged that many of them would ultimately impact on the people required to staff the operation following construction. Therefore, their suitability and applicability were examined from an economic, operational and human perspective. In a continuing effort to improve the quality of life for Raglan employees, as well as the economics of our mine operations, these assumptions are under constant review and scrutiny. There is no doubt that experiences gained, and willingly shared by other North American arctic mining operations, proved invaluable and are a big reason for RaglanÆs overall success thus far. The mining industry is being challenged technically to develop lower grade orebodies at the lowest possible cost. In addition to environmental constraints, serious social, political and moral questions are being asked and added to this list of challenges. Miners throughout the world must improve their operating standards and public image if we want to attract the best possible employees. Remote mining operations provide a unique opportunity to experiment with various human resource concepts as well as demonstrate the industryÆs commitment to environmental and community concerns.

Jan 1, 1998

The Fosterville Goldmine in Victoria employs bacterial oxidation (BIOX« Process) to liberate gold from its flotation concentrate. Gold occurrence is primarily as submicron particles in pyrite and arsenopyrite and has been described as being in æsolid solutionÆ and therefore not amenable to direct cyanidation even with fine grinding. Once liberated by the oxidation process, the gold is then available for cyanide leaching. While the oxidation process is very effective, it has been found that a portion of the liberated gold can become suspended in the liquid phase in what appears to be a colloidal state. This liquid becomes a waste stream during washing of the oxidised solids and the suspended gold is therefore lost. This paper discusses investigations into the causes of the loss and also describes the successful use of quebracho tannin in reducing colloidal gold loss. Laboratory and subsequent plant trials, showed a gain of 2.6 per cent in overall gold recovery based on mill feed and waste stream data.

Jan 1, 2009

By Rogério Ruiz

Atualmente os fabricantes de equipamentos e empresas de engenharia utilizam, na sua maioria, experiência em projetos anteriores para o dimensionamento de silos, chutes, pilhas de estocagem e outros equipamentos de manuseio e estocagem para a indústria mineira. O objetivo deste trabalho é apresentar uma metodologia eficiente e mundialmente reconhecida para a solução e prevenção de problemas de fluxo de sólidos, utilizando método científico e comprovado. Os principais testes laboratoriais para obtenção de propriedades de escoamento dos materiais serão descritos. Os testes necessitam de pequenas quantidades de amostras representativas do material e os parâmetros levantados alimentam a metodologia de análise de escoamento de sólidos ou softwares de simulação numérica, e são essenciais para a correção de equipamentos defeituosos ou dimensionamento de novos equipamentos.

Aug 1, 2018