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By Jewel A. Gomes

Keywords: Electrocoagulation, arsenic removal, fuel cell, windmill, energy simulation, combined Fe-Al electrode assembly Arsenic contamination of well-water in different countries has caused signs and symptoms of arsenic poisoning. Although several physicochemical treatments are presently used for the removal of arsenic compounds from drinking water, an electrochemical treatment, electrocoagulation, is a promising processing technology and currently is the most efficient (above 99% removal) and environmentally friendly technique, particularly if combined with alternative energy sources. Wind and fuel cell technologies can be considered the most promising developmental clean power sources. We will discuss new insights into the materials processing mechanisms and show the coupling of electrocoagulation with fuel cells and simulated wind energy sources. Different electrocoagulation plate materials were considered, along varied currents from the fuel cell to produce maximum arsenic removal. Coupling these technologies will remove carcinogenic arsenic from water sources, and will exhibit efficient usage of these energy sources by producing pure water for human and agricultural consumption.

Jan 1, 2005

By Kaige Zheng, Hongwei Wang, Tong Wang, Yanjun Li, Yongping Wu, JIANQIANG JIAO, Baolin Jiang

Due to the influence of economic development on the demand growth of coal resources, many mines in China have gradually entered deep mining. When the roof of deep coal seam is hard rock, it is easy to cause strong ground pressure with the advance of the working face, which seriously threatens the safety of coal mining. Taking 31,104 working face of a mine as the engineering background, this paper studies and compares the deformation characteristics and stress transfer evolution law before and after the presplitting of the hard roof through the combination of physical similarity simulation, numerical calculation, and field measurement, based on the analysis of the interaction relationship between the breaking and collapse of the composite hard roof, and verifies the treatment effect of hydraulic presplitting through field measurement. The results show that: (1) In the early stage of mining under the composite hard roof, the lower roof is mainly subjected to tensile failure, the voussoir beam structure formed is relatively unstable, and the stope is prone to impact. When the mining distance of the working face is large, the breaking rotation of the upper hard roof voussoir beam causes pressure damage to the lower hard roof, causing the lower hard roof voussoir beam structure to slide and lose stability, resulting in strong ground pressure in the working face. (2) After presplitting of composite hard rock stratum, in the early stage of mining, the range and degree of rock stratum damaged by presplitting are small except for the hard rock stratum itself, and the presplitting effect is not significant. When mining to the first square position, the roof is damaged in advance by presplitting, the overall plastic damage range increases, the damage form area increases, and the damage degree deepens. The vertical displacement of the composite hard roof increases rapidly, and the presplitting effect is remarkable. (3) The evolution characteristics of roof principal stress transfer show that under the dual effects of mining and presplitting, the roof tensile stress area above the goaf is large, the rock failure horizon rises, and the roof failure height is high and the failure degree is deep. The stress concentration degree of the coal mass in front of the goaf is reduced, and the stress concentration range is transferred to the rock mass in front. With the advance of mining, the hard roof in front can break and caving in time, so as to avoid rock burst disaster caused by large suspended roof area. The field ground pressure monitoring shows that the average periodic weighting interval, weighting range, peak value before weighting, and peak value during weighting of the working face after presplitting decrease by 53.5%, 38.03%, 8.63%, and 5.96%, respectively, which effectively reduces the weighting intensity and ensures the safe and efficient mining of the working face.

May 16, 2023

By Gabriela Grespan Câmara

O processo de galvanização a zinco utiliza como principal passivante o metal cromo na sua forma hexavalente. O presente trabalho estuda a remoção por zeólitas do íon cromo (VI) do efluente de uma indústria metalúrgica. Devido a grande concentração de Cr (VI) na amostra, primeiramente foi realizada uma redução deste metal utilizando metabissulfito de sódio, que é o agente redutor e de precipitação ideal para efluentes contendo concentrações de Cr(VI) acima de 100 mg L-1. Em concentrações menores o precipitado apresenta baixa cinética de sedimentação, necessitando de um polimento com um tratamento terciário. Este estudo foi realizado em coluna de leito fixo contendo zeólitas, onde foram filtradas soluções com concentrações de Cr(VI) variando de 0,5 a 10 mg L-1. O efluente tratado foi aplicado no topo da coluna e retirado pelo fundo. A partir dos dados de adsorção foram calculados as isotermas de adsorção (Langmuir e Freundlich). O modelo de Langmuir obtido mostrou-se significativo e preditivo com 97,93% de confiabilidade. A capacidade máxima da zeólita em remover cromo (VI) foi estimada em 0,02 mg de Cr(VI) g-1 de zeólita.

Aug 16, 2017

By Innocent John Arinze, Chidubem Okwudiri Emedo

This contribution presents the first multi-scale geophysical investigation conducted in the Abakaliki and Obubra mining districts (AOMD), southeastern Nigeria, for the exploration of shallowly emplaced (< 50 m) massive sulfide and barite mineral deposits. Raw airborne magnetic data covering the AOMD was acquired and subjected to diverse enhancement routines to facilitate the identification of areas of subtle magnetic anomalies for subsequent ground truthing. The mineralization is mainly made up of galena, sphalerite, and barite. The contrasting physical properties between these minerals and their host rocks make resistivity, induced polarization (IP), spontaneous potential (SP), and magnetic methods ideal to study and delineate the mineralization and possibly locate the ore bodies. Wenner DC resistivity and IP data acquired along the same parallel traverses are inverted using Res2dinv to produce 2D tomography models of resistivity and chargeability. The resistivity and IP models were successful in delineating zones of sulfide and barite mineralization. The ground SP data collected along the same traverses as the resistivity and IP data were interpreted as line graphs. The 1D SP models show a number of central negative anomalies that could be related to sulfide mineralization. These anomalies show fair-to-good spatial continuity and are in close agreement with the result obtained in the resistivity and chargeability model. This study suggests the presence of exploitable mineral deposits in the AOMD and demonstrates the superior interpretative ability of combined geophysical methods over a single geophysical approach.

Oct 20, 2020

By R. J. Gochin, G. D. Schena, R. Spencer

The impact of a mineral project in a developing country is evaluated in the broad context of its economy using input-output models. Minimum economic theory is used to develop simple numerical models. Sets of technical coefficients are exploited in the development of linear models of the productive element of an economy. The analysis allows assessment of the overall economic consequences of a mineral development in which issues broader in scope than financial objectives need to be incorporated in the evaluation. In part 1, the framework for the development of the input-output model is presented. The model is refined to incorporate country-specific behaviour. The increased flexibility of the enhanced semi-input-output model permits a more confident investigation of the economy-wide effects associated with a new project in the mineral sector of a developing country. The relevance of the models is illustrated using an example from Namibia

Sep 1, 1991

By R. R. Faddick

Properties of coal-water slurries were studied in two separate phases: a rheological phase and a pipeline phase. The purpose of the study was to investigate the rheology of fine coal slurries to determine the effect of fine particles in a coal-water mixture on the economic and operational aspects of a slurry pipeline. The slurries consisted of 6x10, 100x200, and 200x0 mesh coal in water. A fourth slurry consisted of a mixture of the 6x10 and 200x0 mesh coal. Brookfield and Stormer rotational viscometers were used to obtain or simulate rheograms for a range of fine coal concentrations, temperatures, and particle sizes. All the slurries were pumped through a 1-inch diameter acrylic pipe. The fine coal slurries were found to encompass four distinct rheological models. The narrow size distribution of the coal slurries was apparently responsible for the high pipewall friction losses, more so than the particle size. A scale-up method applicable to Bingham plastics was found satisfactory for predicting pipeline headlosses of fine coal slurries from rheology data.

Jan 1, 1974

The Kingsgate molybdenite pipes are considered on petrochemical data and field occurrence to be, possibly, epi-magmatic plutonic offshoots grading into hydrothermal bodies. There is reason to believe that the ore is derived from a highly acid granite of type similar to that of the tin bearing areas of northern New England. The mineralogy, microtextures and paragenesis of the ore are discussed.INTRODUCTIONThe Kingsgate Mining Field is situated in steep, heavily timbered terrain 18 miles E.N.E. of Glen Innes and 430 miles north of Sydney. Bismuth and molybdenum ores were discovered at Kingsgate (Yarrow Creek) in 1877. Subsequently some 50 pipes were developed yielding tonnages which at the peak of operations, 1905 to 1920, rivalled production from the rich deposits of northern Queensland.Attempts to revive the field have been made periodically and small parcels of ore have been forthcoming.&apos; During World War II demand for piezioelectric quartz again focussed attention on Kingsgate but twinning and other imperfections of the quartz prevented all but a minor exploitation of the otherwise noteworthy crystals of this locality.There is reason to believe that the ore at Kingsgate is not exhausted through exploration and mining costs would probably be high due to the capricious nature of the pipes and to the irregular distribution of rich ore shoots within them.

Jan 1, 1962

By Gustavo Furigo

A Metalurgia do pó surgiu como uma tecnologia incipiente no início do século passado, e desde então é objeto de inúmeros estudos acadêmicos e industriais, utilizada de forma crescente na indústria metal-mecânica desde a década de 1960. No caso particular de corpos a base de ferro sinterizado e suas ligas um tratamento termoquímico de Oxidação a Vapor, também denominado “Ferróx”, tem sido objeto de pesquisa e estudos por ser uma alternativa muito atrativa do ponto de vista técnico e econômico, melhorando as propriedades tribológicas e promovendo a vedação da porosidade interconectante. Este trabalho tem por objetivo estudar comportamento do tratamento de Oxidação a Vapor em peças de média densidade com composição básica de Ferro, Cobre e Grafite, sinterizadas em condições industriais com diferentes temperaturas. Determinar o comportamento da permeabilidade em função dos parâmetros de processo (temperatura de sinterização, atmosfera e tempo de tratamento de ferrox) e através da Lei de D’Arcy, calcular o coeficiente de permeabilidade (k) dos componentes sinterizados em função dos parâmetros de processo.

Aug 7, 2018

By S. Ragab

The objective of flotation models is to predict the recovery rate of minerals from a flotation cell. In this paper a CFD?based flotation models is presented. The model uses first order rate equation, and the collision frequency is estimated using Abrahamson [1] model with input from CFD two-phase simulations. Spatial distributions of dissipation rate and air volume fraction (also called void fraction) are determined by the two-phase hydrodynamic simulations. Knowing these parameters throughout the machine is essential in understanding the effectiveness of different components (rotor, stator or disperser, jets) on the flotation efficiency. Not only the average pulp recovery rate can be estimated but also the regions of high/low recovery rate can be identified. The CFD-based flotation model presented here can be used to determine the dependence of recovery rate constant at any locality within the pulp on particle diameter, particle specific gravity, contact angle, and surface tension.

Jan 1, 2012

By Arash Habibi, Anna Cable, David Loring, Aleksandar D. Bugarski, Logan Ingalls, Calvin Rutter

The results of diesel particulate matter (DPM) monitoring were used by the underground mining industry to mitigate adverse effects of exposure to DPM. NIOSH Method 5040, currently used for ambient and personal exposure monitoring, does not provide needed real-time information. The objective of this study is to develop a methodology for continuous monitoring of DPM concentrations in an underground environment, founded on the application of the Dekati electrical particle sensor (DePS). The DePS, which measures concentrations of submicron aerosol in real time using a diffusion-charging sensor, was evaluated by comparing the results of the concurrent measurements with reference methods at several locations downstream of the diesel-powered equipment. The DePS results were found to correlate well to those obtained by reference methods. However, it was found that dependence of the response on the physical and chemical properties of aerosols necessitates sitespecific correlation factors for the targeted matrices. The site-specific factors for number and mass of diesel aerosols were derived using the results of concurrent measurements with TSI NanoScan, FLIR Airtec, and carbon analyses performed on the concurrently collected filter samples. The results showed that methodology based on compensated DePS measurements would be suitable for continuous monitoring of DPM in underground mining operations.

Dec 1, 2022

By M. Jacobs

Keywords: Smelting, converting, sulphide, sulphide smelting, platinum, platinum group metals, PGM, base metals, nickel, copper, matte, slag, furnace, electric furnace, Söderberg, electrode, granulation, converter, flash drier, sulphuric acid, acid plant, Ausmelt, Sirosmelt, pyrometallurgy, metallurgy, Anglo Platinum, South Africa Waterval Smelter complex is situated in Rustenburg, in South Africa?s North West Province. The smelter objective is to process wet concentrate to produce crushed, slow-cooled, sulphur-deficient nickel-copper matte rich in platinum group metals (PGMs), gold, and base metals for despatch to the Magnetic Concentration Plant at the Base Metals Refinery. Throughout its history, the smelter complex has been continuously upgraded in line with increasing production demand, changing feeds, environmental initiatives, and advances in available technology. The smelter receives filter cake and slurry from Anglo Platinum concentrators and joint ventures. Wet concentrate is fed through a flash drying process utilising coal-fired, fluidised bed hot-gas generators, to produce dry feed material for the electric furnaces and slag-cleaning furnace. For primary smelting, two electric furnaces are used, each with a rated capacity of 34MW. Furnace matte, containing the bulk of the base metal sulphides and PGMs, is tapped periodically into refractory-lined ladles and granulated using high-pressure water jets, then dried through electrically powered pneumo-driers to become the main feed to the Anglo platinum Converting Process (ACP). Slag is tapped semi-continuously, granulated, and treated through the slag mill. The ACP treats the combined matte output of Waterval, Polokwane, and Mortimer smelters. It is a top-blown furnace, with furnace matte, air, and oxygen being injected into the converter via a lance submerged in the slag. Converter matte is tapped and bottom cast into moulds, slow-cooled, crushed, and despatched to the refineries. Slag is granulated and dried for recycling to the slag-cleaning furnace. ACP slag is fed to the slag-cleaning furnace along with a reductant and a sulphur source. Slag-cleaning-furnace matte is granulated for processing by the ACP, while slag is granulated and processed in the slag mill. The slag mill and flotation circuit treats granulated slag from the electric furnaces and slag-cleaning furnace to recover entrained matte containing valuable PGMs and base metal sulphides.

Jan 1, 2006

By Everaldo Afonso Fernandes

O cenário tecnológico brasileiro passa por transformações profundas, a indústria em geral faz parte desse panorama, dentro dos segmentos indústrias temos a automobilística, onde novas tecnologias são apresentadas e as demais aprimoradas, nesse segmento temos as ligas não ferrosas de alumínio, que com adição de elementos de liga se transformam em ligas de alta performance, assim como as ligas de aços. Elementos de maquinas de ligas de alumínio sofrem modificações em suas propriedades mecânicas com a variação de temperaturas, deformação, composição química entre outras. O presente trabalho objetiva a comparação das propriedades mecânicas dos resultados experimentais da liga Al-0,05%Cu-[0,35-0,45] %Fe-0,22%Zr e de simulações computacionais de chapas para aplicação na indústria automotiva. A liga foi obtida a partir do Al-EC modificado por inserções de ferro na faixa de [0,35 - 0,45] % e 0,22%Zr. Posteriormente, após a solidificação da liga em molde unidirecional horizontal, os lingotes foram transformados em perfis de 3,0mm e submetidos a ensaios mecânico de tração. Na parte de simulação computacional as propriedades mecânicas foram medidas usando chapas finas de aço e chapas mas espessas de alumínio, as propriedades obtidas nos ensaios reais, foram utilizadas como paramentos das simulações das chapas de alumínio, objetivamente a comparação das propriedades mecânicas com os resultados experimentais da liga estuda. Os resultados dessas análises permitem avaliar que a liga Al-0,05%Cu-[0,35-0,45] %Fe-0,22%Zr pode ser aplicada em componentes estruturais na indústria automotiva que trabalharem estaticamente na forma de fuselagem de automóveis de passeio ou veículos de trabalho com boas propriedades mecânicas.

Oct 30, 2017

There are many compelling reasons why correct sampling schemes should be standard practice in the mining industry, yet there are numerous examples where poor sampling practices are known to exist in the business yet permitted to continue. It is not just technical issues that can be ascribed to the reasons for the continued use of incorrect methods. This paper proposes non-technical reasons why incorrect sampling practices continue, and identifies potential ways to overcome them.

Mar 1, 2010

By Limao Zhang

This paper presents a novel model to assess the risk of adjacent buildings in tunnelling environments based on Extended Cloud Model (ECM). ECM is an organic integration of Extension Theory (ET) and Cloud Model (CM), where ET is appropriately employed to flexibly expand the variable range from [0, 1] to (-8, +8), and CM is used to overcome the randomness and fuzziness during the gradation of evaluation factors. The risk level of a specific adjacent building is assessed by the correlation with the cloud models. A confidence indicator ? is proposed to illustrate the rationality and reliability of evaluating results. Ten buildings adjacent to Wuhan Metro Line Two (WMLT) are randomly chosen among hundreds of adjacent buildings for a case study. Results have proved to be consistent with the actual situation. Compared with other traditional evaluation methods, ECM has been verified to be a more competitive solution with high calculation accuracy, wide adaptability, as well as simplified computer programming. There are no stringent requirements on the quantity of training data during the modelling process, and the original data can be directly entered into ECM without a normalization procedure, avoiding the potential information loss. ECM can be offered as a decision support tool for the risk assessment in urban tunnelling construction and worth popularizing in other similar complicated projects.

Aug 1, 2013

By M. E. Adam

This report describes the construction and testing of large (30 ft high by 55 ft wide) stopping and overcast structures in an oil shale mine. The work was undertaken to develop construction techniques and cost data, and to measure leakage rates on full scale structures in an oil shale mine. A design data base was developed by reviewing industry practice, oil shale industry plans, and technical literature. Alternate layouts for room and pillar mining were examined to find ways to reduce the size and number of ventilation control structures. Six full size stoppings and one overcast were built in the Colony Pilot Mine. Leakage rates were measured using both SF6 tracer gas techniques and the ?brattice window? method. The leakage was measured both before and after a full scale face blast. Blast air pressures were measured across two of the stoppings. Cost and leakage data were used to evaluate the projected overall performance of various combinations of the stoppings in a two-panel oil shale mine.

Jan 1, 1986

By Fabio Schusterschitz da Silva Araújo

A unidade do Grupo SIMEC em Pindamonhangaba tem capacidade de produção de 560 mil toneladas/ano de produtos destinados à construção civil. Para abastecer a planta, é utilizada água de poço com pH, condutividade e alcalinidade altas, além de restrições quanto à disponibilidade. Isto gera desafios para o seu uso, e para a água de reposição do sistema de resfriamento dos moldes a água passa por um sistema de osmose reversa. No primeiro semestre de 2016, houve contaminação da água de molde, com a formação de uma incrustação de coloração branca, de aspecto oleoso e diferente das incrustações normalmente encontradas. Este fenômeno reduziu significativamente a vida dos moldes, o que levou à necessidade de paradas constantes para a troca e aumento significativos dos custos. Foi montado um grupo de trabalho de todas as áreas envolvidas, operação, manutenção e condicionamento químico para descobrir as causas e corrigir o problema. Este trabalho mostra as causas, as ações tomadas e os resultados obtidos.

Oct 30, 2017

By B. E. Grant

THE major metal mine operations of the United States Smelting Refining and Mining Company in Utah are in the Bingham area. The Company also owns and operates metal mines in the Ophir district, twelve miles south of Bingham, and in the Tintic district, 28 miles south of Ophir. Operations of the Company in the Park City area have been idle since early in World War II. These mining camps, lying at moderate elevations, serviced by railroads, hard-surfaced highways, in close proximity to mills, smelters, cities and towns, fertile valleys, winter and summer vacation areas, and airports are probably as favorably situated as any mining camps in the world. The Bingham district, known principally for its copper production from

Jan 1, 1948

By L. A. Morely

The overall objective of the subject contract was to investigate the application, economic, and safety considerations of electrical-shock prevention techniques applied to surface and underground mines. Volume I of the four-volume final report starts by summarizing all research performed, and synopses of the three other report volumes are included. The balance of this volume concerns one major task of the contract, the protection of maintenance personnel. After specifying the scope of work for the task, electrical is defined, and needed ground-fault relay characteristics to prevent ventricular fibrillation are established. This is followed by an analysis of alternating-current systems, a comparison of these systems with respect to body currents, and the advantages and disadvantages of the various ground-fault protection techniques. An analysis of direct-current systems for off-track vehicles is then covered. These analyses form the basis for the research recommendations which along with suggestions for future research, conclude the report volume.

Jan 1, 1982

GENTLEMEN, lt is with much pleasure I meet you tonight at this the second meeting of the Australasian Institute of Mining Engineers, held in Western Australia, and I sincerely thank you for the honour you have conferred upon me in electing me as your President. I greatly appreciate the distinction, and will endeavour to fulfil the duties of the office to the best of my ability, and hope to prove a worthy successor to those gentlemen who have held the position before me. On behalf of the local members of the Institute, I extend a hearty welcome to the members from the other States of the Commonwealth, who have come so far to attend this meeting, and also to the non-members whom we have invited this evening. We are especially pleased to have Mr. Gregory, our Minister of Mines and Railways, and the Government and School of Mines officials with us; and I take this opportunity to thank the Premier, Mr. Gregory, and the Government officials for the assistance given us, and for doing so much to make the visit of our members from the other States so pleasant and instructive. I have also to thank the Mayor and Councillors of Kalgoorlie for the courtesy and hospitality given to our members, which is much appreciated.I assume you want me to follow the time-honoured custom of giving a Presidential address...

Jan 1, 1909

By José Geraldo da Silveira, Luiz José Gonçalves, André Mendes Carneiro Lyrio, Raylander Rocha Pessoa, Péricles Guimarães Oliveira Aguiar, Guilherme Ribeiro do Espírito Santo, Filipe Soares Pontes

Este trabalho tem como objetivo apresentar a origem do projeto inovador do cadinho do Alto-forno 2 além do planejamento, a implantação e os resultados obtidos no Alto-forno 2 da Aperam South America após a reforma. O trabalho de pesquisa e desenvolvimento teve início em 2012 após a primeira marcha fria com conseqüente redução das temperaturas da soleira. Foram realizadas diversas reuniões, discussões e seminário sobre alto-forno com especialistas de diversas empresas. A mudança de redutor carvão vegetal para coque por seis meses serviu para comprovar parte da teoria construída pelo time da redução. Para, por fim, culminar no conceito por trás do problema do AF2 e então o novo design do cadinho que foi proposto e implantado na reforma iniciada em dezembro de 2017. Após sua implantação, conforme teorizado pelo time, uma nova gama de resultados e patamar de operação foram atingidos, comprovando diversas das teorias formuladas.

Oct 1, 2019