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By J Westh, S Rashleigh, L Gallagher

Mining companies are moving towards automated haul trucks and other equipment. One reason for this is that if automated trucks can operate in a standard pattern over and over again without variation, then human error is reduced, if not eliminated.The challenge for mining production leaders/managers is to ensure operators follow standard operating procedures for load and dump operations, with each operator doing the same thing, every time. However, operators are only human and inconsistent performance is rife at every mine site. The finger may be pointed at the operators for not doing as instructed. The clarity and variability of trainer instructions may be considered causal to the problem. Herein lies the problem. Almost all operators believe they are following the procedure very closely; moreover, they all demonstrate a strong desire to conform to instruction.Using video analysis and feedback, each operator can be shown where and by how much they differ from the benchmark set by their company. Operators, often for the first time, can see definitively what they are doing, compared to industry best practice.The technology utilised by real-time video (RTV) crews measures time, distance and angles. It can overlay the video of the operator at the load site, with video of the perfect pass. Operators are amazed when they see how near to, or how far they are from best practice.The footage and data gathered by RTV assists operators in understanding exactly what adjustments are required to increase proficiency. It also assists load and dump superintendents to identify where in the process they are losing time. When translated to overburden removal or mineral/resource extraction, the result is large production economies without the need for large capital investment in new automated technology.CITATION:Westh, J, Gallagher, L and Rashleigh, S, 2012. Improving safety and mine productivity using real-time video technology, in Proceedings International Mine Management 2012, pp 173-188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 20, 2012

By Gilson Neves da Silva, Luciana Sgarbi Rossino, Adriel de Brito Maciel Trindade

O objetivo deste trabalho foi de analisar a influência da variação de manganês e cromo na resistência ao desgaste abrasivode aços austeníticos ao manganês aplicados em britadores de minério e verificar mecanismos de encruamento. Este material possui grande importânciatanto para o setor de mineração quantopara a economia do país. Para tanto, produziram-se ligascom teor de manganês (Mn) variando entre 12 e 21%, contendo cromo (Cr) entre 0,31 a 2,06 %. A resistência ao desgaste foi determinada através da realização de ensaios de micro-abrasão por esfera fixa. Para a análise dos mecanismos de encruamento, realizaram-se ensaios de impacto por martelamento seguido de metalografia ótica e perfil de dureza. Os resultados evidenciaram que o aço com percentual mais elevado de manganês com adição de cromo possui maior resistência ao desgaste abrasivo. Observou-se que o mecanismo atuante no encruamento dessas ligas é maclação de deformação, podendo elevar a dureza destes aços em valores quatro vezes maiores que sua dureza inicial. Conclui-se que o teor de Mn e Cr presente nesses aços influenciam na resistência ao desgaste abrasivo, sendo o Mn de maior influência.

Mar 1, 2019

By V. A. Chanturiya

The results study the minerals oxidation were obtained by us during the methods of microscopic, FT-IR spectroscopic, XRD and chemical analyses of sulphides in tailings of copper-nickel wastes in Kola peninsula. Sulphide minerals begin to oxidize already at the stage of stockpiling and initial stages of storing. The proportion of non-ferrous metals and magnesium oxide increases with time, calcium partially precipitating in the form of gypsum. Comparison of heavy metal contents in pore solutions in cur-rent and stale copper-nickel ore concentration tailings has revealed a significant difference in practically all the parameters. The lower metal contents in current tailing pore solutions (by 5~30 times) are probably due to the presence of float reagent residues blocking oxidation. Much lower concentrations of magnesium and calcium can be accounted for by the difference in kinetics: the rate of sulphide oxidation at this stage is much higher than that of solution interaction with non-metallic minerals as the result of which the solid phase ? solution equilibrium is not achieved. It is generally believed worldwide that it the mining wastes with acidic pore solutions that pose the greatest hazard for the environment. Our findings suggest that although the solution pH in all the samples is higher than 7.8, the contain heavy metal concentrations by far exceeding permissible values. The direct determination of the total and silicate Ni contents in the tailings from current production and in storage tailings has shown that both sulphide and silicate Ni forms occur in tailings. However, the role of silicate Ni is much larger in the storage tailings. The average silicate Ni content accounts for 10% of the bulk Ni content in the current tailings and it increases to 40% in the storage tailings. Thus, the storage tailings are marked not only by sulphide oxidation and the removal of water-soluble sulfates, but also by the interaction of sulfates with the silicate matrix. Although complete equilibrium is not achieved even within 30 yr under polar-region conditions, the major part of the Ni in fine-grained fractions passes into silicate form. The probability of Ni transition to the silicate form directly correlates with the dispersion of the material and the amount of chemically reactive serpentine and hydrochlorite. The migration of Ni as sulfates and its precipitation by chemically active silicates distorts the distribution of this component in the coarse- and fine-grained fractions that are typical of tailings from the current production of copper-nickel ores. On the one hand, the variation of the mode of Ni occurrence in storage tailings lowers the value of technogenic raw materials as a source of this metal.

Jan 1, 2014

By G. C. Li

Gold extraction using iodide leaching from refractory carbonaceous gold ores was studied. Thermodynamic analysis of iodide leaching chemistry had been carried out. Eh-pH diagram of Au-I2-I--H2O leaching system showed that the coordinating active forms from iodides were I3- and I-, while the major coordinate compound formed during iodide leaching was AuI-. For leaching parameters optimization, technological parameters such as I2 concentration, I2 :I- ratio, oxidation assisting agents, liquid/solid ratio, and leaching duration were studied. The leaching results showed that the average Au leaching rate reached 91% and 92% for oxidized ore and roasted primary ore respectively. Leaching process proceeded in weekly acidic or neutral slurry at ambient temperature; the leaching duration was 4 hours. After that gold was extracted from the pregnant liquor by activated carbon adsorption ? desorption ? electrowinning process. Gold recovery was over 93% in the adsorption process, while the gold recovery in electrowinning process was about 95%, provided that the initial gold concentration is 40mg/L or larger. For iodine regeneration it is enough to add hydrogen peroxide in excess into the filtrate after gold electrowinning, all the iodides existing in the solution in any forms would be precipitated in the form of elemental iodine.

Jan 1, 2014

By Alen Shibu Joseph, Arvind Rajnarayan Singh, Mudila Dhanunjaya Rao, Kamalesh K. Singh

In this article, the cementation of major impurities from zinc sulphate leach solution by the addition of zinc dust was studied by considering different parameters including time, mesh size, and percentage of excess zinc dust. The output obtained from various experiments was utilized for the design of experiments. A multi-level categorical factorial design with a quadratic model was employed during this study. Results were predicted to minimize the concentration of impurity metals in the solution by altering the parameters. Furthermore, these predicted results were validated by performing another experiment. Successfully, it showed that the predicted and experimental data values were close to each other. The predicted optimized values were 40 min, 100% excess zinc dust, and 300 mesh size for copper; 42 min, 100% excess zinc dust, and 300 mesh size for cobalt; 37 min, 100% excess zinc dust, and 300 mesh size for cadmium; and 34 min, 100% excess zinc dust, and 300 mesh size zinc dust for nickel. At these optimized values, the experimental results showed 99.99%, 55.7%, 99.6%, and 76.6% cementation efficiencies for copper, cobalt, cadmium, and nickel respectively. The statistical design of experiments for the effective cementation of impurities corroborates the economic feasibility of optimizing parameters for the proposed process.

Jul 18, 2022

By Kuniaki Murase, Tetsuji Hirato, Yasuhiro Awakura

"Electrodeposition of CdTe was studied using aqueous ammonia-alkaline electrolytic baths in which Cd11-and Te1V-ions are dissolving as Cd11(NH3)/+ and Te1vol-ions, respectively. Ca-thodic polarization curves of the baths suggest the presence of strong interaction between the Cd11-and Te1V-ions; electrodeposition of tellurium is inhibited by the presence of Cd(NH3)/+ ions. The interaction makes it possible to electrodeposit CdTe films with stoichiometric composition. Polycrystalline CdTe thin film of about 1 µm thickness was electrodeposited at 343 K from ammonia-alkaline solutions (pH= 10.7) containing TeO32-(<20 mmol dm-3) and Cd(NH3)/+ ( < 60 mmol dm-3) ions. Increasing Cd(NH3)/42+/TeO32- mole ratio or decreasing total concentration of ammonia/ammonium-ion gave flat and smooth crystalline CdTe deposits at constant cathode potential-0.70 to -0.30 V vs SHE at 343 K.IntroductionCadmium telluride (CdTe) is well-known as a compound semiconductor whose band gap, i.e. 1.44 eV, is suitable for solar energy conversion with a photovoltaic cell. Various methods, such as CVD (chemical vapor deposition) and electrodeposition, of preparing CdTe thin films for solar cells have been investigated.Acidic sulfate solutions with a pH of 1-2 are usually employed for CdTe processing by electrodeposition.1-3) The electrodeposition of compound semiconductors is usually achieved (i) at a higher cathode potential than the redox potential of less-noble species, can in this case, and (ii) under the condition of diffusion-limiting current of a more noble species, Te1Y.4) There-fore, a suitable CdII/TeIV concentration ratio in the acidic electrolytic baths, resulting in the deposition of stoichiometric CdTe, is determined by the diffusion-limiting current density of TeIV- reduction, i.e. the concentration of HTeIVO2+ · Since the solubility ofTe1v species HTeIVO2+ in the acidic solutions is quite low, the rate at which CdTe is deposited from the acidic solutions is extremely slow."

Jan 1, 1998

By ArcelorMittal Tubarão - Aços Planos

Fatos Relevantes - Produ&ccedil;&atilde;o anual de 4.491.854 t de a&ccedil;o bruto - produ&ccedil;&atilde;o est&aacute;vel em rela&ccedil;&atilde;o &agrave; 2012. - Produ&ccedil;&atilde;o anual de Bobinas Laminadas a Quente de 3.726.871 t - 7,8% de eleva&ccedil;&atilde;o em rela&ccedil;&atilde;o a 2012. - Unidades Geradoras da Central Termel&eacute;trica em manuten&ccedil;&atilde;o aproveitando per&iacute;odo de menor produ&ccedil;&atilde;o relacionado &agrave; parada do Alto Forno 3. - Redu&ccedil;&atilde;o relevante na gera&ccedil;&atilde;o de energia el&eacute;trica interna devido menor disponibilidade de combust&iacute;veis (off-gas) e redu&ccedil;&atilde;o de produ&ccedil;&atilde;o na Sol Coqueria adequando &agrave; demanda de coque do grupo ArcelorMittal Brasil.

Jul 31, 2018

By Y. Q. Yang

Jig is a kind of conventional and old gravity concentration equipment, which is mainly used in the preconcentration of medium particle fractions of low-grade nonferrous metal ore. In the past ten years, studies on jigs have made a great progress on separation of coarse and fine particle fractions. At the same time, pneumatic jigs have been widely used in processing of nonferrous metal ore. In this paper, pilot test study and commercial operation for several kinds of jigs used in Dachang con-centrator has been introduced. Dachang mining area of GuangXi province is rich in mineral resources, where many minerals exhibit various complex properties. Many elements such as Sn, Pb, Sb, Zn, S, As, Cu, In, Ag, Gd, Ag, Ga, etc, were found in the run-of-mine ore (ROM). At present, Dachang concentrator produces tin concentrate, lead-antimony concentrate and zinc concentrate. Other valuable elements get enriched and recovered in above concentrates. Dachang Mine with a mining operation history more than sixty years will end its mission on the rich ore resource exploitation. At present, low grade ores are porcessed in the concentrator, and the concentrator begins to run at a loss upon processing the low-grade and refractory ore. Heavy medium cyclones were used in the concentrator for processing 20-4mm fraction, Gongge jigs for 4-2mm fraction, and cone concentrator combined with spiral concentrator to discard the tailings of -2mm fractions. In order to minimize overgrinding, table flotation was used to recover some liberated cassiterites in a complex processing technology. Therefore, the concentrator is difficult to manage. Many years studies have shown that heavy medium cyclones and spiral concentra-tors can be replaced by sawtooth shaped wave jigs to discard 50% tailings to improve the grade of feed. And the feed was divided into rich one and poor one to minimize overgrinding of valuable cassiterites with different grinding mills. In this case, the recovery of the valuable minerals can get improved and the flowsheet was simplified. Moreover, the concentrator begins to make profit with reduction of cost. At the same time, pollution in the concentrator gets reduced and the working condition gets improved too. Sawtooth shaped wave jig was used in Changpo concentrator for replacement of cone separators and spiral concentrators to discard the tailings of -4mm fraction, and the yield of discarded tailings got improved from 30% to 50%. Grades of tin, lead and zinc in the tailings are lowered from 0.15%, 0.12%, 0.7% to 0.06%, 0.05%, 0.4% respectively, with a loss reduction of tin, lead and zinc from11%, 9%, 10% to 7.5%, 6%, 5% respectively, corresponding to the increasement of recovery of tin, lead, zinc from 52%, 50%, 55% to 56%, 56%, 62% respectively. Cost of the concentrator for processing one-ton ROM was therefore dropped from RMB155.28 to RMB119.74. Changpo concentrator lost RMB2.5 million in 2003, but it made a profit of RMB0.92 million in 2006 after the innovations. Batac jig was used in Tongkeng concentrator to discard the coarse tailings at 20-4mm, with a discarded yield of 35%, and the grades of valuable minerals got improved with a recovery above 95% for tin, lead-antimony and zinc.

Jan 1, 2014

By Eulogio Velasco, Jose Nino, Marcos Cardoso

"Recycling of aluminum scrap for production of secondary alloys used for automotive applications is increasing continuously. Automotive alloys require a strict control to remove alloy impurities, inclusions and excess of magnesium. The advantage of aluminum is its recyclability with large energy and emission savings with minimal loss in material properties. The aim of this work is to study the magnesium removal from recycled aluminum by chlorine injection in a reverberatory furnace, and removal by an oxidation process at high temperature in an industrial rotary furnace.The magnesium removal by gas injection is carried out by the reaction between chlorine and magnesium, with its efficiency associated to kinetic factors. In the rotary rapid oxidation of aluminum and magnesium elements at high temperature is characterized by the formation of surface films composed of magnesium oxide. Additionally this work reviews the benefits of an efficient demagging process.IntroductionThe advantages of using light alloys for automotive applications include fuel economy improvement, greenhouse gas reductions and polluting emissions. These characteristics makes the aluminum alloys an attractive option for automotive components such as powertrain products and other critical parts like cylinder heads and blocks. [1]Aluminum alloys coming from recycled automotive components, used beverage cans (UBC) and wrought alloys have positive effects in the energy savings and current environmental trends. Producing a scrap recycled aluminum ingot consumes approximately 5% of the energy required to produce a primary aluminum ingot from bauxite ore. [2]"

Jan 1, 2011

By W. M. LONIE

Address by the President of the Institute (Mr W M Lonie) in making the presentation of the Certificate of Honorary Membership to Sir Ian McLellan, K.C.G.M, K.B.E. Address by Sir Ian McLellan after accepting the award.

Jan 1, 1979

By R. S. Jones

"Fording Coal Ltd. is now in its fifth year of a 15-year contract to supply 3 million long tons of clean coal per annum to its Japanese steel-making customers. The mine employs both conventional truck-shovel and unconventional ""walking"" dragline coal mining techniques in multiple-seam pits. This paper describes the present and future application of the 60-cu.-yd dragline and truck-shovel pre-stripping fleet in 1•ecovering 5- to 40-footthick coal seams in mountainous terrain. Deep blastholes, coal flow demands, spring ""run-off"", seam and inter-seam thrust faulting, limited seam outcrop data and regional faulting are a few of the problems encountered in this application. The author discusses these problems and their solutions as applied at Fording Coal Ltd."

Jan 1, 1976

Thermo Fisher Scientific is the worldÆs leading supplier of analysers for laboratories and process industries. The companyÆs X-ray fluorescence (XRF)-based slurry immersion probes were originally developed by the acquired Amdel Instrumentation. These analysers have found limited application within wet beneficiation plants for measurement of iron. The recent trend of renewed efforts to maximise recovery from existing resources and lower costs has increased industry interest in online analysis. In the mid-1990s the company developed online analysers (the light element slurry analyser û LESA) for slurry applications using the prompt gamma neutron activation analysis (PGNAA) method. The company has successfully installed LESA for the direct measurement of lighter impurity elements in Brazilian plants using flotation for rejection of silica. A case study is presented. The PGNAA technique has the unique ability to provide elemental analysis of bulk materials on a conveyor belt. The company released its eighth generation cross belt Omni analyser using PGNAA in 2007. Results from a recent project with sinter are presented. The Niton range of hand-held XRF analysers is also supplied by Thermo Fisher Scientific. These handy devices are finding widespread use in the mining industry to provide quick and easy analyses in exploration settings. In contrast to PGNAA this is a surface technique. A prototype for light element analysis is being tested for iron ore.

Jan 1, 2007

By David Leidel

A revolution in hydrocarbon well completions within the last thirty years has enabled drillers to tap the resources of known gas plays in an economically viable manner and deliver to market natural gas supplies for industrial, transportation and domestic use without the importation of liquefied natural gas from verseas. An added benefit has been the convenient location of one of these gas plays, the Marcellus Shale, in the Northeastern states strategically close to a major natural gas market, namely the cities and towns of the New England and Mid-Atlantic states. As a sidelight, the development of the tight gas reservoirs and their subsequent production has created thousands of jobs in an otherwise lackluster economy.

Jan 1, 2014

By D. Nutakor

This paper presents the results of a study conducted on a slope failure that occurred in the Q7 mining cut at Rio Tinto&apos;s Bingham Canyon Mine. The slope failure occurred in a weak rock mass with an estimated rock mass rating of 25%. The failure mechanism was of the circular type, involving ten 15-m (50-ft) benches and covered a total width of 152 m (500 ft). The analysis used Adam Technology&apos;s photogrammetric method with a two-dimensional rock fall simulation program (RocFall software) to design a 3-m- (1 0-ft-) high berm located 7 m (24 ft) from the toe of the failed mass. Back and predictive analyses were performed on a cross-section through the slide using Slope/W software, resulting in flattening the interramp angle (IRA) from 44° to 38°. This design modification produced a factor of safety (FOS) of 1.14. Sensitivity analysis involving FOS vs. pore water pressure showed that FOS is sensitive to water saturation. A dewatering system using a series of horizontal holes drilled below the slide and dewatering holes drilled from a drainage gallery has since been established to improve the stability of the slope. Throughout the one-year period since this investigation, no significant slope movement has been detected by the slope stability radar, and mining is in progress below the failure.

Jan 1, 2012

By Mariana Beatriz dos Reis Silva

Neste trabalho foi avaliada a influência do tempo entre passes na interação entre precipitação e recristalização durante o processamento termomecânico do aço ISO 5832-9. A evolução da microestrutura foi investigada por microscopia ótica, eletrônica de transmissão e EBSD. Observou-se que quanto menor o tempo entre passes, maiores foram as tensões necessárias para promover a deformação e menores foram os tamanhos dos grãos e precipitados obtidos. Somente precipitados de TiNbN foram encontrados após o encharque e NbCrN durante o processamento. O material sofre recristalização dinâmica e partículas de 50 nm foram efetivas no ancoramento dos contornos de grãos e discordâncias.

Aug 8, 2018

By P. Kiruthika, A. Murali Krishna

Soil liquefaction is a dangerous phenomenon that involves huge damages during strong earthquake ground motion event. Stone columns (SCs) are widely used as liquefaction mitigation element which is expected to perform the improvements against liquefaction hazard by densifying, increasing the stiffness and rapid dissipation of excess pore water pressure in the surrounding soil. Although in the recent times few studies on the behaviour of stone columns in the seismic zone has evolved, the performance of SCs in the multi-layered soils is not extensively examined. This paper presents the numerical investigations on the performance of SCs installed in the multi-layered soils as a liquefaction mitigation measure against the seismic loading. The acceleration time histories, Excess Porewater Pressure (EPP), vertical displacement and stress ratio evaluated along different depths using PLAXIS 2D. With the installation of stone column there is a considerable reduction in the acceleration amplitude, which in turn reduces the EPP and vertical displacement at different locations and the amplitude of reduction depends on the soil stiffness levels at the depth.

Sep 1, 2022

By A Hitchen

A general outline is given for the determination of copper, nickel, cobalt, zinc, lead, cadmium, bismuth, manganese, uranium, molybdenum, vanadium, sulphate and fluoride by polarographic or amperometric methods in a variety of ores or metallurgical products. The detection of oxygen in gas mixtures by an amperometric method used as a safety device is also discussed. Introduction I N this paper, a general outline will be given of the polarographic and amperometric methods used for the chemical analysis of various ores and metallurgical products in the Chemical Analysis Section of the Extraction Metallurgy Division of the Mines Branch. The methods to be discussed will be confined to those based on the use of normal D.C. polarography and will not include those methods which utilize a cathode-ray, square wave, pulse or A.C. type of polarograph. For the sake of convenience, ? the polarographic methods will be discussed according to the type of supporting electrolyte employed, as the same electrolyte may serve to determine more than one element in more than one type of ore. Amperometric methods will be discussed according to the element to be determined rather than

Jan 1, 1965

By Marcos Paulo Kohler Caldas

Após a edição da RoHS Directive 2002/95/EC, diretiva que entrou em vigor em 1º de julho 2006 proibindo a utilização de seis substâncias perigosas: chumbo, mercúrio, cádmio, cromo hexavalente, bifenilos polibromados e éteres difenil-polibromados, fabricantes de equipamentos eletroeletrônicos passaram a utilizar soldas livres de chumbo (lead free) para montagem de suas placas de circuito impresso. A SAC 305 é um tipo de solda muito utilizada pelas empresas fabricantes de placas de circuito impresso. O presente trabalho visa caracterizar este tipo de solda verificando sua composição e identificar se a mesma se encontra livre de elementos perigosos ao ambiente. Avaliou-se a extração de metais como Ag e Sn através de digestão ácida em água-régia e rota HNO3 a temperatura ambiente. A composição do licor lixiviado foi caracterizada por espectrometria de emissão óptica com acoplamento de plasma induzido (ICP-OES). Os resultados indicam que a solda SAC 305 atende a RoHS, possui 2,7% Ag, 96,4% Sn e 0,9% de outros metais e a melhor rota para extração de Ag foi a HNO3 e para Sn foi a água-régia.

Aug 7, 2018

By M. Werner

Mining in the Coeur d&apos;Alene Mining District has been going on for over 100 years with a long- term continuation very likely. Mining is presently carried out at depths below the -5000&apos; horizon. As mining continues at ever increasing depths, higher in-situ rock stresses and subsequent rock deformation is encountered making mining costly and hazardous. To provide access for men and materials in such areas, a wooden raise preparation structure is typically built. Although these structures provide adequate support and access, they have proved to be very costly to construct and maintain.

Jan 1, 1986

By Frederico Mayerhofer

A produção brasileira de minério e pelotas abastece siderúrgicas de diversos países e contribui significativamente para o desenvolvimento global. Com a redução acentuada do preço do minério de ferro a redução de custos de produção de pelotas se torna ainda mais necessária. Nos fornos das usinas de pelotização é consumido o combustível responsável pelo maior custo de produção das pelotas, que é o gás natural. O presente trabalho tem como objetivo reduzir o consumo de gás natural utilizados nos fornos do tipo grelha móvel das usinas de pelotização, através da otimização dos fluxos de gases e temperaturas necessárias ao processamento térmico das pelotas.

Aug 17, 2017