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By Isabel F. Barton, Matthew J. Gabriel, CARSON ROBERTS, JOHN LYONS-BARAL, LEON DUPLESSIS, Mark D. Barton

Geometallurgical assessment of orebodies in the mining industry typically relies on bench-scale or lab-based characterization techniques. In this study, we investigate drone- and tripod-based field hyperspectral imaging as a potential addition to the geometallurgy toolkit in multiple applications. This pilot study tests hyperspectral imaging for largescale mineral mapping in and around the active Lisbon Valley copper mine, including natural exposures, previously producing U-V mines, highwalls, dumps, and leaching sites. Tests include different (supervised and unsupervised) mineral data classification methods, varying mineral spectral reference libraries, comparison with ground-truth geological and spectroscopic mapping and sampling, and integration with LiDAR data. The results show that hyperspectral scans can produce spatially registered maps of the distribution of different spectrally active mineral types over dumps, highwalls, leach pads, and natural outcrops. Clays, other phyllosilicates, carbonates, and sulfates showed up particularly well. The sensor was also able to distinguish dry from lixiviant-saturated areas and map different clay types on the leach pads, and shows promise for differentiating types and health of vegetation. These results suggest that hyperspectral imaging, if coupled with robust ground-truthing, can be a useful complement to existing geometallurgical techniques in the mining industry, such as geological mapping, blast hole sampling and automated mineralogy identifications, and handheld spectrometry. In particular, hyperspectral imaging has promise for mapping the distribution of acid-consuming minerals; mapping the distribution of swelling, sliming, and heap-blinding clays; and pinpointing problem areas on heap leach pad surfaces.

Feb 10, 2021

By Rameshwar Sah, PK GHORUI, LR SINGH, SIVALINGARAJU BARISETTY, SHYAM YADAV

Fly ash is a by-product generated by the combustion of coal in thermal power plants. Its disposal is a major environmental concern for these power plants. Though a considerable part of fly ash is used in cement making and brick manufacturing, a substantial quantity remains unutilized. Bentonite is commonly used as binder in the micropelletization of process waste to attain the mechanical strength required for handling and transportation. The present paper deals with the partial replacement of bentonite with fly ash in the micropelletization process without affecting the quality of the micropellets. The mechanisms of both the binders are discussed. The bonding of particles by bentonite is a physical mechanism, while fly-ash bonding is a chemical mechanism. Silica and alumina are the major constituents present in fly ash along with lime. In the presence of water, the alumino-silicates and unhydrated lime present in fly ash undergo a pozzolanic reaction and form cementitious bonds, which hold the particles together. Use of fly ash as alternative binder for bentonite has cost benefits besides providing a better utilization option for fly ash.

By M. Dupuis

It has been previously demonstrated [1,2] that using selective collector bar rodding has a big impact on the uniformity of the current density at the top surface of the cathode block and hence on the intensity of the horizontal current in the metal pad, The present study investigates the impact of using selective collector bar rodding on the MHD stability of a 500 kA aluminium electrolysis cell, For this purpose the recently developed MHD package for the aluminium reduction cell time dependent behavior is used.

Jan 1, 2005

By Jean Philippe Santos Gherardi de Alencar

O fenômeno de colagem é a formação de aglomerados de pelotas, denominados clusters, devido à sinterização do ferro gerado durante o processo de redução. O resultado disto é a elevação da perda de carga nos reatores de redução direta. Tal fenômeno vem sendo estudado por vários pesquisadores, pois as práticas operacionais dos reatores têm priorizado o uso de temperaturas de bustle gas (BG) cada vez maiores, o que potencializa o aparecimento dos clusters. Uma alternativa para controlar a colagem é por meio de utilização de agentes de coating (AC’s). Em relação às matérias primas utilizadas como AC´s, as questões que surgem agora são as seguintes: Como se comportam os AC’s em temperaturas muito elevadas de BG? Qual seria a maior temperatura possível de BG? A fim de começar a entender a melhor maneira de responder a estas questões foram realizados alguns testes de caráter exploratório e não convencionais para avaliar o comportamento de alguns materiais de coating a elevadas temperaturas de redução. Os resultados destes testes mostraram a possibilidade dos AC’s funcionarem a temperaturas maiores que a de inicio do amolecimento da carga e que, nestas temperaturas, a sua granulometria pode ser parâmetro determinante para seu desempenho. O aprimoramento dos ensaios de simulação do processo de redução em reatores de redução direta é fundamental para responder as questões que se apresentam em relação ao tema.

Aug 2, 2018

By Osmar de Sousa Santos

NiTi shape memory alloys (SMA) have been widely used as construction materials due to their shape memory and superelastic properties. Usually the application of the NiTi alloy is in the wire form, which is ideal shape to make springs, orthodontic arc-wire and endodontic files. Since our research group (ITASMART) started producing NiTi wires, it was noticed that NiTi SMA produced by Vacuum Induction Melting (VIM) presents carbon contamination, which is due to the melting process. Therefore, alloys rich in carbon remove titanium from matrix, forming precipitates of TiC (titanium carbide). Also, Ti2Ni precipitation removes titanium from the matrix and these two precipitates TiC and Ti2Ni can produce internal volumetric defect in the wire drawing process. Seeing the importance of NiTi wires as base of many applications, this work studies the formation of volumetric defects caused by precipitates in the wire drawing process of a NiTi wire drawn down to 0,39 mm in diameter.

Aug 8, 2018

By C. S. Ek

As a continuation of previous work, further tests have been carried out to recover silver from the residues obtained in a zinc jarosite process. Selective flotation has been performed with different reagents, and ?cleaning steps have been introduced to upgrade the silver concentrate. Leaching of crude residues, as well as flotation tailings, has been carried out with cyanide and thiourea. Finally, the different beneficiation methods are compared, and the industrial aspects? of their application are reviewed.

Jan 1, 1990

By Emmet K. Oslen

Kaiser Steel Corporation, the pioneer steelmaker on the Pacific Coast, was founded by the late Henry J. Kaiser. In 1944 the Company purchased from the Southern Pacific Railroad an iron ore property 200 miles east of Los Angeles known as Eagle Mountain. Today the domestic operation of Kaiser Steel Corporation consists of the iron mine at Eagle Mountain; two coal mines, one each in Utah and New Mexico; an integrated steelmaking complex at Fontana, California; and several steel fabrication and erection facilities along the west coast. Kaiser Steel also has interest in Hamersley Iron, Ltd., Australia, and Kaiser Resources, Ltd., British Columbia. Eagle Mountain Mine is located about 80 miles east of Palm Springs and adjacent to the southeast corner of Joshua Tree National Monument. The area is one of the most arid in the world averaging only two inches of rain annually. Geologically, the mine is at the western edge of the Basin and Range Province which covers about one-half million square miles of the western United States. The Province is typified by north to northwesterly trending fault block mountain ranges separated by sediment filled valleys, Production has totaled over 82 million tons of finished products since the first shipment in June, 1947. Over 500 million tons of material have been mined from the deposit to date. Eagle Mountain Mine is noted for the pioneering use of the largest and most up to date equipment to mine and process its ore. In 1961 Eagle Mountain received the first fleet of 100-ton haulage trucks in the mining industry. There were thirteen semi-trailer units in the fleet. The first 12 to 17-yard size shovel in the mining industry was placed in operation at Eagle Mountain during 1962. Rotary drilling was introduced at Eagle Mountain in 1954 to replace churn drilling. Eagle Mountain was the first major mine to use metallized slurry when three aluminum slurries were introduced for primary blasting in 1962.

Jan 1, 1972

By G. Machiavelli, P. Bevilacqua, G. Ferrara, T. P. Meloy

During several years of operation in Europe, South Africa and other locations, the Tri-Flo process has demonstrated substantial improvements in dense-medium dynamic-separation systems. The reasons for this improvement are: • a high-sharpness separation due to the multistage system and the application of new concepts in the design of the regeneration circuit and in the control of the medium Theology, and • the possibility of performing two cuts at different densities using a single separation device and a single regeneration circuit. This paper discusses the above points in detail with particular reference to the multistage technology (based on the circuit analysis theory) and to the control of the medium rheology (based on recent work in the modeling and simulation of the rheological behavior of dense suspensions). Concerning the multidensity separation, information is given on the new three-stage separator where the high-density separation is performed by the first stage and the low-density separation is performed by the second and third stages. This configuration (already realized in two operating plants) was selected because no particular sharpness was required at the high-density separation, while high sharpness was required at the low-density separation. However, the configuration can be inverted or a fourth stage can be added (at very low additional cost) to provide two stages for each separating density. The importance of achieving a high sharpness separation is related to minerals (industrial minerals in particular) where the density difference of the phases to be separated is very low (as in processing of lithium ores, feldspar- and others). Information is provided on plants operating in South Africa and Canada, for the beneficiation of lithium minerals and on a plant under construction in Italy for the beneficiation of feldspar. Finally, the importance of making the separation at two densities is emphasized with particular reference to coal; i.e., producing a low-ash premium coal and recovering, in the middling, a by-product without losing heating value. Also, very important for some minerals is the production of a high-grade concentrate (at the first stage) suitable for sending directly to metallurgy (e.g., chromite ores) and the production of a low-grade concentrate that can be further treated. In this way, a higher overall recovery of the valuable mineral can be achieved, and, at the same time, a reduction of the treatment costs can be obtained. All of the above applications were once considered impossible.

Jan 1, 1995

By R. Kobialka

In the article results of experiments over jaws? linings in jaw crushers with different shaping of working surface were presented. Following sets of jaws were under investigation: immobile plain jaw and moving jaw with grooving surface. Grooving jaws have groves with circular, triangular and trapezoid cross section. In order to evaluate efficiency of comminution both the grain composition of product and the content of irregular grains were determined, as well as the size of crushing forces and process efficiency were measured. For the combination: plain jaw with grooved one, a good results were obtained as regards the grain composition of product and the content of irregular grains. Crushing forces were higher at crushing with mixed types of jaws (the one plain, the second grooved), in comparison to crushing with using both grooved jaws. Efficiency of the process was definitely higher for mixed jaws.

Jan 1, 2014

By Etiene Pereira de Andrade

Este trabalho avaliou a influência da deformação na formação de martensita e consequente resistência à corrosão do aço inoxidável austenítico AISI 304. O aço foi deformado em cisalhamento de 10%, 25%, 30%, 50% e 55% de deformação efetiva e em seguida mergulhado em solução contendo água do mar natural e artificial. As amostras imersas em solução de água do mar artificial exibiram aumento da massa enquanto as mergulhadas em água natural, redução. Esses resultados podem ser associados com a aderência inicial e estável de íons metálicos advindos dos cloretos, à superfície do material mergulhado em água do mar artificial.

Aug 17, 2017

By Franciele de Almeida Silva

A escória utilizada no refino secundário deve possuir propriedades adequadas para que auxilie no controle inclusionário dos aços. Tendo isto em vista, há vários parâmetros que devem ser levados em conta para se obter uma escória ótima que irá auxiliar na limpeza dos aços. Como uma técnica de medição, o valor de oxigênio total no banho está diretamente relacionado com o número de inclusões óxidas presentes no aço líquido. O presente trabalho tem como objetivo geral o acompanhamento da limpeza inclusionária por meio dos teores de oxigênio total presentes nos aços, para variáveis selecionadas de escória e de processo. A partir das análises químicas de amostras de um aço alto carbono acalmado ao alumínio, foram gerados gráficos com os valores de oxigênio total em função dos parâmetros %CaO/%Al2O3, %FeO+%MnO, basicidade binária, tempo de flotação na torre do lingotamento contínuo e pick-up de nitrogênio; seguido da análise dos resultados obtidos e sua comparação com os dados da literatura. Pode-se então concluir que, para as análises anteriormente citadas, o aço apresentou resultados coerentes com a literatura para todas as análises.

Aug 8, 2018

By Paula Aliprandini

Os minérios limoníticos de níquel apresentam na sua composição metais como ferro, níquel e cobalto, sendo o primeiro o elemento majoritário. A presença majoritária de ferro prejudica a separação dos demais metais que possuem interesse comercial. Para remoção do ferro, técnicas hidrometalúrgicas são usadas. A extração por solventes é uma técnica com foco na separação seletiva de metais. Neste trabalho, foi preparada uma solução sintética baseada nas concentrações dos metais presentes na lixiviação de um minério limonítico de níquel. A solução foi colocada em contato com o extratante Cyanex 272. Este extratante é conhecido pela sua seletividade ao ferro em valores de pH próximos a 2,0. As amostras foram analisadas utilizando a técnica de Espectroscopia de Fluorescência de Raios X por Energia Dispersiva (EDX). Após concluídos os ensaios foi encontrado que durante a extração do ferro, o cobalto foi coextraído junto, mesmo em pHs entre 0,5 e 2,0, indicando que a presença do ferro altera o comportamento do cobalto.

Aug 17, 2017

1. In 2002, a total of 763 nonmetal mining operations reported employment to the Mine Safety and Health Administration (MSHA). Examples of nonmetal mining operations include the mining of clay, trona, barite, phosphate rock, gypsum, talc, gemstones, and pumice. Nonmetal mines comprised 5.3% of all mining operations. • Nonmetal mining operations are located in all but nine states or territories (Alaska, Delaware, Maine, New Hampshire, Rhode Island, Vermont, Wisconsin, Puerto Rico, and the Virgin Islands). • Mines producing common clay comprised 29.2% (n = 223) of all nonmetal mining operations.

Jan 1, 2004

By Robert B. Parsons

"Effective January 1, 1990, mines in British Columbia are subject to a new provincial mining tax statute, the Mineral Tax Act. Under this Act, mines are subject to a two-tier tax system, with a minimum tax payable on ""net current proceeds"" and a higher tax paid on net income. For many mines, the present value of tax paid under the new rules should be comparable to the amount paid under the old rules. Earlier cash payments could pose difficulties, particularly for smaller mines, but existing producing mines could benefit in the short-term.IntroductionEffective January 1, 1990, British Columbia has replaced the provincial mining tax regime under the Mineral Resources Tax Act with a new system under the Mineral Tax Act. The new rules borrow some ideas from other provinces (New Brunswick's two-tier concept, and Saskatchewan's indexed costs) with a view to levying a tax that is fairer to both the producer and the province."

Jan 1, 1990

By Fuming Wang, Xi Chen, Shuai Liu, Changrong Li, Dan Wu, Yaxu Zheng

The effects of B content and austenitizing temperature on hardenability and toughness of Cr–Mo alloy steel have been studied. The results show that the hardenability is deteriorated with increasing B content and austenitizing temperature. With increasing temperature, more and more B containing particles were dissolved in austenite and increase the amount of B atoms segregating at grain boundaries. Moreover, the coarsening grains reduce area of grain boundaries and also increase the amount of B atoms at unit grain boundary, excessive B atoms segregating at grain boundaries promotes precipitation of M2B, which accelerates ferrite nucleation and reduces hardenability. The main elements in M2B phase are Fe, Cr, Mo and B. The B atoms segregating at grain boundaries during austenitizing promote precipitation of M2B during tempering which deteriorate toughness significantly.

Mar 1, 2018

By Aldo L. Furno

Sufficient quantities of combustible vapors are released by some sulfurs to produce flammable atmospheres under prolonged storage. Hydrogen sulfide and carbon disulfide appear to be the principal flammable constituents in the vapor space above molten sulfur. If sufficient carbon disulfide is present, ignition of the vapor-air mixtures can occur spontaneously on contact with the heated surfaces found within storage tanks.

Jan 1, 1963

By Huimin Lu, Zhijiang Gao

Reduction reaction can happen among Al, V2O5 and TiO2 powders. Al can deoxidize metal V and Ti from the metal oxides. The electric igniter can be used to trigger the reduction. The reaction between Al and V2O5 is very intense and release large amounts of heat, but the heat which is needed to initiate the reaction between Al and TiO2 is not enough. These two reactions have been initiated first and V-Al and Ti-Al alloys can be obtained with a higher metal recovery percent. Through adjusting the ratio of Al, V2O5 and TiO2 powders, the system which combines these two reactions can ensured enough heat to react. KClO3 is added to the system, as the ignition agent, in order to make the reaction much complete. Finally, Ti-Al-V alloys can be obtained and need remelt to adjust the constituents.

Jan 1, 2016

By Jos. R. Guiteras

This paper is one of a series published by the Bureau of Mines on mining and milling methods and costs. It describes operations in the Alma district of Colorado in September 1937, supplemented by some additional data collected in July 1938. ACKNOWLEDGMENTS The author wishes to express his appreciation of the friendly cooperation extended him by the mine operators in the district. The greater part of the information was obtained from mine and mill superintendents to whom individual acknowledgment is made in the text.

Jan 1, 1940

By Lingzhi Yang, Feng Chen, Yufeng Guo, Tao Jiang, Zeqiang Xie

Zinc ferrite (ZnFe2O4), one of the major forms of zinc in Electric Arc Furnace (EAF) dust and zinc leaching residue, is very difficult to chemically dissolve in either acidic or alkaline solutions. In spite of the zinc resources in the Electric Arc Furnace (EAF) dust and zinc leaching residue are abundant, there is no mature utilization technology. This situation not only causes the waste of resources, but also produces the harm to the environment. In the paper, the basic principle of this process has been established by revealing the phase equilibria in the CaO–Fe2O3–ZnO system, where Ca2Fe2O5 can be in equilibrium with ZnO rather than ZnFe2O4 at higher CaO region. It has also been demonstrated that the formed ZnO can be solved by ammonia-leaching and Ca2Fe2O5 keep in solid residue, which can be used as a flux for steel refining.

Mar 1, 2017

By Thomas R. Stauffer

The principle that conventional schemes for taxing petroleum or mineral resources are "inefficient" is illustrated using simulation calculations tested against an "ideal" system. Inefficiency is defined as the relative success in maximizing expected government revenues from the resources. Most systems fail because: 1) they leave oil in limbo, i.e. unproduced because of excessive fiscal burden; or 2) they unnecessarily increase the variance in the explorationist'c, rate of return by undertaxing large fields and overtaxing smaller but infra-marginal fields. This increases his discount rate and reduces taxable surplus. An "ideal" tax system is specified which maximizes government revenues while minimizing risk to the operator. Two criteria are developed: 1) the tax falls to zero on fields which yield only the minimum necessary rate of return ("marginal" fields); and 2) the after-tax present value of all fields is the same for all fields above a threshhold size. In particular, marginal fields, while contrib- uting little to expected values, do contribute to reducing variance and hence risk praemia by distributing the exploration costs over a higher probability of successful outcomes.

Jan 1, 1982