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By Adriana Amaro Diacenco

O presente trabalho propõe-se a analisar a influência do amortecimento estrutural inerente de tais materiais submetidos a perturbações estáticas e dinâmicas as quais afetam as características de resposta. A importância deste trabalho insere-se no contexto do controle de vibrações de sistemas de engenharia. Para tanto, é empregada uma técnica de modelagem baseada em elementos finitos. A análise numérica é desenvolvida utilizando a Teoria da Deformação Cisalhante, a qual é implementada em um elemento Serendipity retangular contendo oito nós. O amortecimento é incluído empregando o modelo histerético. As respostas dinâmicas são representadas por funções de resposta em freqüência e autovalores complexos. Simulações numéricas são realizadas visando quantificar os níveis de amortecimento obtidos no tocante às vibrações transversais de placas retangulares e verificar a possibilidade de se aumentar tal amortecimento.

Aug 7, 2018

By José María Lezcano, Diego Urquiaga, Pedro Delvasto, Marcos Garayar

La extracción de minerales ricos en sulfuros metálicos tiene el inconveniente de generar drenajes ácidos (AMD), los cuales causan severos impactos en los ecosistemas acuáticos, el suelo y el recurso hídrico. Como posibilidad de remediación (alcalinización) de estos pasivos, en el presente trabajo se propone el uso de coproductos férricos oxidados (CFO). Luego de presentar las características de un tipo de CFO específico, se muestran los resultados —a escala de laboratorio—sobre la respuesta alcalina del mismo, y se discuten las implicancias de estos hallazgos para el tratamiento de los AMD.

Nov 30, 2020

By M. B. Kime, E. K. Kanowa

"Heap leaching of low-grade copper-cobalt oxidized ore and solvent extraction of copper, cobalt, manganese, and zinc were investigated. Heap-leaching parameters were optimized using agitated and tray batch leaching tests, capped by tests on a pilot semicontinuous heap-leach plant. The optimum pregnant leach solution yielded 2,350 mg/L Cu, 3,800 mg/L Co, 3,600 mg/L Fe, 130 mg/L Mn, 25 mg/L Zn, and 0.58 g/L solids in suspension, with pH and acidity of 1.27 and 3.66 g/L, respectively. Copper, cobalt, and impurities (Mn and Zn) were extracted using (v/v) 30% CP-150, 20% IONQUEST® 290, and 20% D2EHPA, respectively; overall recoveries of copper, cobalt, and impurities were 98, 99, and 70%, respectively.RÉSUMÉ La lixiviation en tas des minerais oxydés de cuivre et de cobalt et l’extraction par solvant du cuivre, du cobalt, du manganèse et du zinc ont été étudiés. Les paramètres de lixiviation en tas ont été optimisés à l’aide d’essais de lixiviation en discontinu sur un plateau, complétés par des essais relatifs à une usine pilote de lixiviation en tas en semi-continu. La liqueur-mère optimale a produit 2 350 mg/L de Cu, 3 800 mg/L de Co, 3 600 mg/L de Fe, 130 mg/L de Mn, 25 mg/L de Zn et 0,58 g/L de solides en suspension, avec un pH et une acidité respectifs de 1,27 et 3,66 g/L. Le cuivre, le cobalt et les impuretés (Mn et Zn) ont été extraits avec un pourcentage volumique (v/v) de 30 % de CP-150, de 20 % d’IONQUEST ® 290 et de 20 % de D2EHPA, respectivement. Les récupérations totales de cuivre, de cobalt et d’impuretés étaient de 98 %, 99 % et 70 % respectivement.INTRODUCTIONBoss Mining S.P.R.L. is a privately owned hydrometallurgical plant located in southeastern Democratic Republic of Congo. It treats oxidized ores of copper and cobalt that are recovered by sulphuric acid heap leaching (Trujillo, Cisternas, Gálvez, & Mellado, 2014; Kime, Kanowa, Mulaba- Bafubiandi, & Diyambi, 2016) and solvent extraction processes (Crane, Urbani, Dudley, Horner, & Virnig, 2009; Fisher, 2011; Kime et al., 2016). The ore to the plant is primarily sourced from the Luita and Mukondo mines. Geological prospecting work by Gecamines and Boss Mining showed that the Mukondo mine contains a very large cobalt reserve not yet exploited, but with grades as low as 0.2%.Currently, Boss Mining is focusing on the production of copper, but is investigating methods to efficiently produce both copper and cobalt. A challenge in the production of cobalt from this ore is its presence in the third oxidation state. This requires the addition of reducing agents, which increases the overall operating cost (Kime & Makgoale, 2016). Cobalt solvent extraction is also very sensitive to impurities such as nickel, zinc, manganese, and aluminum, which are often co-extracted (Swartz, Donegan, & Amos, 2009). This sensitivity to impurities requires the optimization of operational parameters to lower impurity levels as much as possible in the electrolyte."

Jan 1, 2017

By W. G. Miller, J. D. Scott, D. C. Sego

ABSTRACT An overall study was conducted to evaluate the properties and processes influencing the rate and magnitude of consolidation for oil sands fine tailings produced using different extraction processes. As part of the overall study, a comprehensive description of physical and chemical characteristics of fine tailings generated by caustic and non-caustic processes was carried out. Ultimately, the influence of these fundamental properties on the compressibility, hydraulic conductivity and shear strength properties of the fine tailings was assessed. The characteristics of the fine tailings are presented in terms of index properties, mineralogy, specific surface area, water chemistry, liquid limits, particle size distribution and structure. A difference in water chemistry was concluded to be the cause of substantial differences in particle size distributions and degree of dispersion of the comparable caustic and non-caustic fine tailings. The degree of dispersion was consistent with predictions for dispersed clays established by the sodium adsorption ratio (SAR) values for these materials. A linear variation of increasing dispersion with increasing SAR up to a SAR value of about 40 has been suggested, above which fine tailings are completely dispersed. The observed dispersed or flocculated structures (viewed using a scanning electron microscope) supported the predictions based on SAR values.

Jan 1, 2010

By I. L. Sills

Introduction So many minerals and mineral products are used in the glass industry that it would require an unduly long paper to deal adequately with all of them. Only those that go to make up the batch for the more common types of glass will be discussed here, and even with these only, the list is a lengthy one. It is true that for the body of the glass comparatively few materials are required-as silica sand, soda-ash, lime, and feldspar. The others are used mainly to colour or decolorize the glass, or to give it some other desired characteristic, such as high lustre, greater physical strength, or opalescence; but, although they may be present in very small quantities, they are just as in-dispensable to the glass industry as are the main constituents of the batch. Sand Sand is essentially quartz, the dioxide of silicon, Si02. Most glass contains from 71J to 75 per cent silica. Sand for use in the glass industry, or 'glass sand', is obtained both from deposits of unconsolidated material, commonly referred to as 'sand', and from solid rock-sandstone, quartz, or quartzite. For the manufacture of glass, the material must possess a high degree of purity, as noted below, so that, although sand is widespread in most parts of the world, and sandstone, quartz, and quartzite are not at all uncommon, it is only in certain places that suitable deposits are found. At the present time, most of the glass sand used in Canada is imported from France, Belgium, and the United States. The French material, from Fontainebleau, near Paris, is known the world over as a very high quality glass sand. That from Belgium is nearly as good and is lower is price.

Jan 1, 1934

By A. E. Ketler

This report describes a variety of coal mine lighting projects which were funded by the Bureau of Mines in order to obtain underground lighting experience in support of new lighting requirements for underground coal mines. Low coal and high coal, narrow and wide entries, conventional and continuous mining, ac and dc power, bituminous and anthracite, and machine mounting and area lighting were some of the variables covered in this program. Also evaluated was the OCENCO fluorescent caplamp.

Jan 1, 1979

By J. Oré Iwanaga

El presente texto señala el uso de geocontenedores como una alternativa en la deshidratación de lodos líquidos ( relaves) a través del programa MATLAB que permite la determinación de los parámetros de diseño más importantes. La ejecución del programa se realizó en la planta concentradora de la Compañía Minera Raura, ubicada en la cordillera occidental entre Huánuco y Lima, sierra central del Perú donde se estableció la presión de bombeo (Po) y resistencia del geosintetico (T),a partir de datos conocidos como: perímetro (L) y peso específico del lodo líquido.

Jul 1, 2014

By A. R. Javadi

Pyrite (FeS2), chalcopyrite (CuFeS2), sphalerite (ZnS) and galena (PbS) generate hydrogen peroxide (H2O2) when placed in water, with pyrite generating the most amount of H2O2. The order of these minerals for generating H2O2 in water is: pyrite > chalcopyrite > sphalerite > galena. In previous research, the methods of generation of H2O2 in the grinding mill were studied. In this study, data from experiments were included by using MODDE 9 software for six parameters composed of water, grinding media, particle size; adding collector to the grinding, and adding depressant and pH. Finally the optimal condition was achieved. According to the results, most of the recovery is related to the particle 75 μ size and when using processed water, adding 100% collector and without depressant and pH 10. The most recovery of lead in the case of the use of fresh water is in the case of 100% collector, without depressant, pH 10 and 150 μ particle size. Maximum recovery in fraction size 45 μ in the case of water process is 100% collector, without depressant and pH 10. Maximum depressant of pyrite will be the fraction size 75 μ, distilled water, without collector, 100 depressant. Keywords: Sulfide mineral, hydrogen peroxide, flotation, oxidation

Jan 1, 2020

By Michael J. Mujadin

Since the late 60's, planners at American Natural have known that natural gas supplies from traditional sources will be insufficient to maintain a consistently high level of service in the near future. This dwindling of traditional gas reserves will force American Natural and other gas companies to seek new and more exotic sources of supply. In recent years a number of alternative supply sources were considered, including arctic gas, LNG, and SNG based on naptha, LPG and coal feedstocks. Several combinations, all of which included SNG from coal were selected as the most suitable alternative sources of gas supply for American Natural, and thus our company embarked on the formation of a coal gasification project in the early 70's. Work began with the evaluation of available coal supplies in the United States in late 1970. Western North Dakota was selected for several reasons: large contiguous reserves of lignite were available near the surface, similar to German brown coal for which the Lurgi gasification process was originally developed; the conditions for land reclamation in the area are favorable; and the people in the area have a positive attitude toward well ordered development.

Jan 1, 1977

By François Robert

"The Eastern Abitibi Sub province (Quebec segment), contains two main types of gold deposits: the common quartz-vein type and the rare pyritic type. Both occur in areas dominated by volcanic rocks and are spatially associated with major fault zones.Quartz-vein gold deposits consist of simple to complex networks of quartz-carbonate-pyrite veins in reverse shear zones and extensional fractures. They occur in areas dominated by mafic volcanic rocks and are commonly associated with small syn- to late-tectonic porphyritic felsic intrusions. Associated alteration, which postdates peak metamorphism, is dominated by carbonatization, sericitization and pyritization of the wallrocks. These deposits formed late in the geologicalevolution of the Abitibi.Pyritic gold deposits range from deformed massive sulphide lenses to zones of syntectonic pyrite-rich veinlets and associated pyrite disseminations. These deposits occur in environments dominated by felsic volcanic rocks that are typically converted to sericite schists near the deposits. The associated pre-metamorphic aluminous alteration is now characterized by metamorphic sericite, andalusite, kyanite and chloritoid, overprinted by a late retrogression of alumino- silicates. These deposits probably represent deformed volcanogenic massive sulphide deposits, but the timing of gold introduction in these is not fully understood.The differences in geological attributes reflect significant differences in the genesis these deposits: the pyritic deposits probably have a multistage genesis, including a pre-tectonic stage, in contrast to a single stage late-tectonic genesis for the quartz-vein deposits.RESUMELa partie Est de la Sous-Province de l’Abitibi( segment québécois) renferme deux types de gites d' or: ceux de type ""veine de quartz"" et ceux, plus rares, de type ""pyriteux"". Ces deux types se trouvent dans des secteurs particulièrement riches en roches volcaniques et mantrent une association spatiale avec des zones de failles majeures.Les gites de type ""veine de quartz"" correspondent à des réseaux de complexité variable de veines de quartz-carbonate-pyrite se développant dans des zones de cisaillement inverse et des fractures de tension. Ils se concentrent dans les régions dominées par des roches volcaniques mafiques et s’associent fréquemment à de petites intrusions porphyriques felsiques syn- a tardi-tectoniques. L’altération associée ace type de glte est postérieure à la phase majeure du métamorphisme et consiste en une carbonatisation, une sericitisation et une pyritisation des épontes. La mise en place de ces gites est tardive par rapport à l'évolution géologique de l'Abitibi.Les gites d' or de type pyriteux consistent en des lentilles de sulfures massifs déformes, des zones d' abondantes veinules pyrite uses syntectoniques, et des zones de pyrite disséminée. Ces gites se retrouvent dans des empilements contenant surtout des roches volcaniques felsiques qui sont transformées en schiste à séricine pres des gisements. L’altération a l’umineuse pre-metamorphique associée a ce type de glte a donné naissance, lors du metamorphisme regional, a la sericite, a 'andal ousite, a Ia lcyanite et au chloritoi""de; par la suite, les alumino-silicates ont été affectes par une alteration retrograde tardive. Ces gites representent probablement des depOts de sulfures massifs volcan gènes déformes, mais la chronologie de la mise en place de l'or dans ceux-ci est encore mal comprise.Les caractéristiques géologiques propres à chacun de ces types de gites reflètent des conditions de formation différentes: le type ""pyriteux"" montre une histoire génétique polyphasée, incluant une étape pre-tectonique alors que le type ""veine de quartz"" s’est développe au cours d’une seule phase tardi-tectonique."

Jan 1, 1990

By D. Randolph Berry

The U.S. Bureau of Mines awarded a contract to Foster-Miller Associates, Inc. (FMA) to provide recommendations on the safest, most practical methods for complying with new regulations requiring that all underground coal miners have a self-contained, self-rescuer (SCSR) -a device capable of supplying, in an emergency, 1 hr of self-contained oxygen (no breathing of mine air). This report develops information and recommendations which could be used during the early stages of nationwide compliance, especially in the areas of inspection, testing, and underground storage of SCSRs. Volume I contains an Executive Summary, Introduction, Definitions, Recommended Guidelines for District Managers and Mine Operators, and a Storage Plan Checklist and Sample Form.

Jan 1, 1981

By Joe B. Rosenbaum

New applications and concepts of solvent extraction as a unit operation in extractive metallurgy have been developed in the last decade. Wider use is being made of established solvent extraction techniques in processing spent nuclear fuel elements and in winning columbium-tantalum, hafnium-zirconium, thorium, tungsten, uranium, and vanadium. Commercial application has been extended to recovery of beryllium, boron, bromine, copper, molybdenum, phosphorus, rare-earth metals, and rhenium. Systems in use and proposed typically extract metals or salts as anion, cation, or neutral species from aqueous media by reaction with a recycleable organic reagent.

Jan 1, 1971

By I. H. Warren, E. Devuyst

A review of the physical and chemical aspects of the direct leaching of metal oxides has been given and com- pared to recent data of the authors and co-workers. The physical aspects, including the anisotropy of the dissolution, the hydration and the zero point of charge of some metal oxides are discussed first and then the kinetics of the dissolution of metal oxides are considered. A general mechanism of the leaching of oxides which describes most of the observed results is proposed.

Jan 1, 1973

By G. Fazel Jahromi

Enargite, known as one of the major arsenic containing copper minerals, with approximately 19% arsenic, introduces challenges to typical processing options. In most hydrometallurgical processing methods, arsenic remediation occurs after the copper recovery in an autoclave or in a stepwise neutralization process. In this study, the in situ precipitation of scorodite was investigated during an atmospheric leaching process in the presence of carbon-based catalysts and chloride media. The effective parameters of initial ferric addition, temperature, catalyst addition, and oxygen sparging rate were studied and the ferric behaviour was monitored during the scorodite precipitation. The most influential parameters on efficient scorodite precipitation are found to be: initial ferric addition, catalyst to concentrate ratio, and temperature. A 99% scorodite precipitation yield was achieved in this process.

By H. R. Manouchehri

"Pyrrhotite (Po) is one of the most abundant sulfide minerals in processing industry and must be rejected in most cases. Particularly, Po rejection and its selectivity against pentlandite (Pn) have long been a challenge due to similarities in the mineral composition of the two minerals and the collectorless flotation characteristics of Po. Xanthates have been widely used to promote sulfide mineral flotation; however, in the presence of xanthates, the redox potential established at the mineral/solution interface is most important, determining the flotation performance. In this paper, the importance of electrochemistry in Po and Pn flotation has been demonstrated and a comprehensive study was conducted on two different feed streams (i.e., magnetic concentrate and scavenger cleaner streams, containing magnetic and nonmagnetic forms of Po, respectively), from Vale’s Clarabelle Mill in Sudbury, Ontario, with an objective to determine if improvements in Po rejection and Pn recovery could be achieved by controlling pulp electrochemistry. By conducting a series of flotation tests under different Eh conditions and reagent usage schemes, it was revealed that higher Po content in the magnetic stream may protect Pn from being oxidized, improving Pn recovery. The results indicated that at low oxidizing pulp chemistry, the rest potential for the Pn is still high enough to allow the formation of dixanthogen to promote its flotation. Using a Pt electrode, it was found that by controlling pulp potential at -50<Eh< +50 mV, the Pn recovery and Po depression would be satisfactory. The results, using mineral electrodes (Outotec Chena analyzer), indicated that selective separation can be achieved if low-to-moderate oxidation potentials (0 to 100 mV) or reduction (0 to -100 mV) potentials are monitored using Pn and Po electrodes. Mixing two streams at 50:50 wt % would be possibly beneficial in selective separation.IntroductionPyrrhotite (Po), Fe1-xS, is one of the most abundant sulfide minerals in the processing industry. It is an iron-deficient sulfide that occurs either in monoclinic or hexagonal form. The monoclinic one is richer in sulfur and is ferromagnetic, whereas the hexagonal Po is poorer in sulfur and has no magnetic properties. In general, the ferromagnetic properties of natural Po increase with increasing sulfur content. Although Po holds significant iron content, it is not used as a feedstock for the iron and steel industry due to the difficulty in achieving complete removal of sulfur. The common availability of iron oxide ores makes the iron sulfides irrelevant for the steel industry."

Jan 1, 2015

By Wm .. O. Vanderburg

This paper describing the mining practices at the Block P mine of the St. Joseph Lead Co. at Hughesville , Mont . , is one of a series of similar papers being prepared by the Bureau of Mines on mining practices , methods , and costs in the various mines of the United States .

Mar 1, 1931

By A. W. Hale

IN a work published in 1838, De Morgan, the author of the article on "Probabilities,&apos; in the Encyclopedia Metropolitana, says " The method of least squares is not yet introduced into the affairs of common life,….that many things which are demonstrable only by the higher branches of mathematics are looked upon as useless." And he mentions an instance in which "a method was suggested for estimating the relative importance of boroughs, by considering their population and contributions to the revenue com-

Jan 1, 1881

By Baohua Guo, Xuelin Yang, Tingkan Lu, Hailin Sun

The work presented in this paper mainly involves two parts. Firstly, the fundamental characteristics of the high pressure carbon dioxide gas fracturing technique (CO2 technique), including, a proposed method of TNT equivalence calculation, which is used to calculate the TNT equivalence of discharge of CO2 technique, and the comparison of the explosion volume generated by dynamite and expansion volume of liquid carbon dioxide is conducted to show the differences of fragmentation capacity between the two of them. Secondly, the coal seam fragmentation mechanisms of CO2 technique are proposed, including, 1) Gas jet cutting and penetration by shaped charge, 2) Gas volume expansion by changing phases of carbon dioxide, 3) Coal seam softening by destress blasting and 4) Coal seam fragmentation by discharge vibration, associating with the mechanisms, the equations for calculating fragmentation radius are developed and verified.

Jan 1, 2017

By P. S. Dash

With implementation of stringent environmental regulations, ultra clean coal technology development programs have gained significant importance worldwide. As far as Indian scenario is concerned, most of the coals present in India are of drift origin and low grade, containing high mineral matter varying from 15% to greater than 50%. The inorganic or ash constituents of Indian coals are finely disseminated through the organic or carbonaceous constituents so, that commonly used physical beneficiation techniques are of only limited value in affecting separation. Chemical processes involve addition of chemicals, which react with the mineral matter and allow its easy removal. The present study envisages the effect of aqueous alkali leaching followed by acid washing on the removal of mineral matter from two different captive coals of Tata Steel at elevated temperature and pressure. The experiments are conducted at desired conditions using a bench scale pressure reactor set up having proper data acquisition and control system. The research study revealed, that it is possible to reduce the ash content up to 70% by this method. The alkali content of the product clean coal does not increase whereas the silica and alumina content reduces by nearly 58% and 62% respectively. Significant reduction in the phosphorus content is observed after the acid treatment. The crucible swelling number of the feed coal improves after the treatment. The mechanism of demineralisation was evaluated by analyzing the coal samples before and after the alkali and acid treatment using scanning electron microscope (SEM). Because of the acidic nature of the silicates and aluminates, they dissolve into the NaOH solution and form sodalite. Sodalite is partially soluble in the alkali solution. The hydrates formed during alkali treatment are partially removed due to acid wash. This study in overall provides an insight into possible alternative methods of beneficiation for removal of ash from high ash Indian coals.

Sep 1, 2012

By Federico Oviedo Kernan

El texto señala el procedimiento de la campaña de higiene, sanidad y seguridad industrial realizada en Pamplona y el diseño de un programa de seguridad en la ingeniería minera. Ante el incremento de accidentes registrados por influencia del medio ambiente -en tanto condiciones materiales y anímicas en el trabajador-, la Marcona Mining Company creó un departamento de seguridad e higiene industrial, a fin de mejorar sus condiciones y sentar las bases de la difusión entre los participantes de la zona. Entre los servicios y facilidades del aspecto externo tenemos: sanidad y profilaxia, servicio social, cooperativa, servicio médico, casas-comedor, medicina preventiva, curativa y medicina social. Mientras que en el aspecto interno, encontramos la higiene industrial, los ambientes de trabajo, iluminación, espacio, vapores, protección personal y ruido. Asimismo, es importante el rol del ingeniero de Seguridad quien además de su experiencia(5 años) y profesionalismo, se convierte en un intermediario del trabajador y la empresa, ofreciendo soluciones y evaluando las dificultades presentadas. Por ello, se hace importante la función del Pool o Asociación de diversas empresas en tanto difundan la información de la campaña entre los colaboradores de la empresa, a través del uso de prensa y propaganda para el desarrollo de seguridad de las mismas.

Jul 20, 1959