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Various methods and software have been trialled for simulation of Au grades at Boddington Mine. This covers in-house and public software as well as sequential and turning bands methods. The diversity of options was further expanded with comparison of point and direct block simulation. Some difficulties were encountered in incorporating high-grade restrictions. Altering parameters or software can make very significant differences and give results varying from estimations. This paper details a new simulation run with validation and tests for local calibration (or progressive correction) of the simulations to the estimations, focusing on reproduction of statistics. This approach brings to the forefront the question æwhat is the purpose of the simulations?Æ Results and some ideas for future applications at Boddington are summarised.

Sep 26, 2011

By Afranio Marcio Costa

No lingotamento contínuo a busca pelo aumento de produtividade tem sido realizada com sequências longas, ou seja, várias corridas e muitas vezes com aços de diferentes composições químicas. Isso resulta na geração de placas de mistura e vários trabalhos buscam entender este processo. Este estudo tem como objetivo validar o modelo matemático de mistura existe no lingotamento da Gerdau Ouro Branco para garantir a correta aplicação da região de mistura, visando atender às especificações dos produtos, norma ASTM A36. Os resultados encontrados nas placas amostradas confirmaram a eficiência do modelo para estimar a zona de mistura. Além disso, para garantir a aplicação dessas placas na norma estudada foi utilizado o modelo de previsibilidade de propriedades mecânicas existente na laminação de chapas grossas. Finalmente, os resultados reais de composição química, limite de escoamento e resistência encontrados nas chapas avaliadas confirmaram as previsões dos modelos e atenderam às especificações do aço.

Oct 30, 2017

By Mark Zablocki, Dakarai McCoy

Ground vibrations are an unavoidable effect of driving piles and may pose a risk to nearby infrastructure and the comfort of adjacent occupants. Driven-pile-induced ground vibrations are known to vary widely based on ground conditions, pile material, and installation means and methods. A monitoring sensor to record ground vibrations during pile driving is necessary for understanding potential impacts to sensitive infrastructure and should be considered when implementing a monitoring program anticipating ground vibrations. The implementation of a vibration monitoring program historically relies on experiential-based decision-making, which may result in the costly vibration monitoring of low-risk infrastructure. Prior understanding of anticipated ground vibrations is necessary to create an appropriate monitoring program. A framework is proposed for organizing data from past monitoring programs and quantifying the anticipated risk of driven-pile-induced vibrations. An example of risk quantification from data imported to ]a cloud database is presented by comparing driven steel H-pile and prestressed precast concrete vibration monitoring measured and collected by Haley & Aldrich between 2010 and 2020. The methods presented within the example can be applied to quantify a first order approximation of risk for ground vibrations at proposed driven pile sites based on the measured performance of previous sites with similar ground characteristics and pile installation methods. The presented novel data managements tools allow for a quick aggregation of vibration data with similar site conditions.

Sep 8, 2021

By Juan Manuel Ojeda Sarmiento

"El Proyecto de Estandarización de la Intervención Social en las Comunidades es una herramienta de gestión social, cuyo objetivo es sistematizar las buenas prácticas de relacionamiento comunitario aplicadas en la minería peruana, a través de la incorporación del concepto de desarrollo comunitario como su principal soporte. De esa manera, se facilitan las actividades de las empresas minero-energéticas en las comunidades de su entorno de influencia directa, durante sus principales fases: exploración, factibilidad, construcción del proyecto, operación y cierre. En esta perspectiva, el presente trabajo señala el concepto de las Relaciones Comunitarias en las industrias minero-energéticas, donde se presenta los objetivos de la estandarización de la intervención social en comunidades y se plantea nuevo enfoque de relaciones comunitarias, basado en la gerencia de actitudes y percepciones de los grupos de interés, ubicados en los ámbitos rural y urbano del entorno de influencia de la empresa, para lograr el consenso social. "

Sep 14, 2009

By A G. L Pratt

Inclined troughed belt conveyors are more frequently being selected from a range of alternatives, which include shafts and trucks for ore haulage in underground mass mining projects. Belt conveyor haulage systems are being operated with lifts exceeding those normally associated with truck haulage systems and approaching the limits of shaft haulage systems. A belt conveyor haulage system, in this context, incorporates subsystems for: crushing,tramp detection and removal, andhaulage. This paper presents details of recent inclined troughed belt conveyor systems for underground mining operations, and explores the application of inclined troughed belt conveyors for the increasing demands of future underground mass mining projects.

Jan 1, 2008

By David T. Farber

"Stabilization of an existing cellular tower foundation system without dismantling the tower or compromising the existing foundation system was accomplished by installation of a jet grouted pile system. The tower was originally designed to be placed on a steep hillside and to be supported by a mat foundation founded on existing bedrock. The as-built conditions of the tower foundation system showed it to be constructed on a combination of loose fill of varying thickness and native stiff silts and gravel material. To avoid the potential of differential settlement, a jet grouted pile foundation system was installed to the top of bedrock. The jet grouted pile system was rapidly installed over a two-day period so as to not delay operational permitting of the tower.INTRODUCTIONA tri-legged lattice cellular communication tower was constructed on the side of a steep hill located in a mature hard wood forest. Access to the site as well as available work area was limited to small track type drill rigs and equipment. The original tower design required the tower to be supported by a mat foundation bearing directly on bedrock. Based on a review of the foundation construction and results of a subsurface investigation, it was discovered that the foundation was built directly over a loose fill material that varied in thickness from 0 to 4.27 meters (0 to 14-ft). Because of the uncompacted nature and varying thickness of the loose fill materials, the tower would be susceptible to differential settlement which, could lead to tower instability.The objectives of this project included the following:• stabilize the mat foundation against differential settlement without removing the existing tower structure or foundation system• rapidly complete stabilization activities to allow operational permitting of the towerSOIL CONDITIONSThe subsurface soil conditions that the tower mat foundation rested on were evaluated by installing three borings in a row from the inward slope portion of the mat foundation (B-1) to the outward slope portion of the mat foundation (B-3). Figure 1 illustrates the subsurface soil stratigraphy. The three borings encountered the following subsurface conditions:"

Jan 1, 2005

By A. Spearing

According to a 2000 NIOSH report, about 100 million rock anchors are installed annually in coal mines in the USA. Most coal mines have conditions that are conducive to corrosion of the rock anchor and ancillaries (such as plates), yet the effect of this on the performance of the anchors has not been adequately researched and its effects are not understood or quantified in the USA. There is considerable research into corrosion in civil engineering applications on surface and underground but the corrosion of coal mine rock anchors is not necessarily the same because: ? In underground civil structures, water ingress is usually stopped as part of the construction process. ? Many rock bolts in mines are only partially resin grouted leaving part of the reinforcing member exposed to corrosive conditions. All cable bolts in coal mines are only partially resin grouted. ? Even when mine bolts are fully grouted, shrinkage cracks occur and the rock stresses can change due to adjacent mining that can cause the resin column around the bolt to fracture further under external shear or tensile stresses. Most coal mines therefore have ideal conditions for bolt corrosion.

Jan 1, 2010

By R Klepper

Separation of leach residue suspended solids from pregnant liquor solution is an important step in hydrometallurgy flowsheets. Alternative flowsheet options are counter-current decantation (CCD) thickeners or counter current washing (CCW) horizontal belt vacuum filters. Extensive sedimentation and vacuum filtration simulations have been completed by FLSmidth on leach discharge slurries to indentify equipment capacity and performance. These data were used to compare Capex and Opex for CCD versus CCW alternatives. In addition, Capex and Opex for large horizontal belt vacuum filters with filtration areas greater than 250m2 are compared to current state of the art sizes of 150m2. This paper presents this information and discusses various advantages and disadvantages.

Aug 8, 2011

By Noelia Farías, Luis Lozada

La voladura representa una de las operaciones unitarias más importantes en toda la cadena de producción del proceso minero. Su objetivo es lograr un adecuado grado de fragmentación de la roca, produciendo a la vez el menor daño posible en la proximidad del sector volado como taludes del tajo, botaderos, comunidades cercanas, estructuras y/o edificaciones. Tal es el caso de un proyecto de desarrollo de minado en un sector adyacente a una faja transportadora que ha sido ejecutado con éxito. Este proyecto incluyó realizar voladuras a una distancia menor de 40 metros a la estructura en mención, así como a 20 metros de una tubería de combustible.

Sep 29, 2023

By Hormando Leocadio Júnior

A otimização operacional no setor de desbaste da Linha de Tiras a Quente da Usiminas, Ipatinga, proporcionou redução do tempo de processamento dessa etapa, criando-se condições para aumento das temperaturas dos esboços na entrada do Trem Acabador (TA). Desse modo, para manutenção das temperaturas de acabamento dos laminados dentro da faixa de controle desejada, seriam necessárias menores velocidades de laminação no TA. Com a finalidade de garantir temperaturas desejadas na entrada do TA, que possibilitem adequadas velocidades, foi desenvolvido um sistema de controle de temperatura de esboço, que é acionado e desligado automaticamente na região inicial (topo), na extensão necessária do esboço. Esse sistema permitirá uma ampla exploração da nova condição de desbaste em menor tempo, com menor variabilidade da temperatura de entrada no TA, prevenindo ocorrências de estiramentos e de carepa, por temperatura alta nos topos e baixas nas bases dos laminados, maior uniformidade de propriedades mecânicas dos produtos, assim como aumento na capacidade produtiva.

Jul 30, 2018

By Cláudio Batista Vieira

Nos últimos dez anos grande atenção tem sido dada a tecnologia de realidade virtual, sendo sua aplicação cada vez mais marcante para o desenvolvimento de ambientes virtuais imersivos em diferentes áreas. Nesse trabalho é apresentada uma descrição da plataforma inovadora em realidade virtual de uma planta industrial de produção de ferro-gusa verde. O modelo 4D do alto-forno a carvão vegetal contempla o projeto detalhado de engenharia dos equipamentos e a partir da integração de softwares e hardwares foi modelado um ambiente tecnológico em realidade virtual de alto grau de realismo. Essa plataforma foi customizada para ser utilizada como Indústria-Escola de Educação Profissional para escolas técnicas, universidades, institutos de pesquisa, indústrias e museus. A Usina-Escola Siderúrgica utiliza um sistema de blended learning, agregando assim as vantagens existentes tanto na modalidade do ensino presencial tradicional, como na abordagem do ensino a distância.

Aug 1, 2018

By T M. Nester, D J. Reardon, A N. Page, B J. Barsanti

The load capacity of a friction bolt has long been regarded as 4 t/m of embedment for ground support design analysis and supported by in situ pull test results. In recent years, the authors have observed lower pull test results or inconsistent results which were rarely sighted in the early 2000s. The lower pull test results indicated in some cases that reliable friction bolt capacity (≥90 per cent of results) is closer to 3 t/m of embedment with some geotechnical engineers adjusting the ground support parameters in the design work accordingly. This can be in contrast with other mines which reliably obtain 4 t/m (or greater) using the same suppliers bolt in similar ground conditions. This raised several questions: • What is the effect of poor installation (bolt twist or bolt hole deviation)? • Does the performance of friction bolts vary in different rock masses? • Does bolt performance vary between suppliers? • What effect does increased jumbo feed/percussion/rotation settings have? • Have the bolt dimensions or steel strip width changed? • Have the physical bolt properties changed? • Have the steel properties changed? This paper was aimed to answer as many of these questions as possible and discuss each variable in detail. This project included friction bolt trials at various mine sites across Australia, multiple friction bolt manufacturers, steel manufacturers and laboratory analysis. The paper also includes discussion on what the authors consider best practice for pull testing. It should be noted, the terms ‘friction stabiliser’ and ‘split set’ used in this paper are used in a generic manner and is not linked to any specific ground support supplier. Whilst its acknowledged within the industry the term split set and friction stabiliser is used interchangeably, the authors acknowledge that the term split set is a trademark of Split Set Mining Systems and has been used in context in this paper.

Nov 29, 2022

By Y. B. Zhang

China is rich in iron ore resources, but most of these ores are low-grade, polymetallic and refrac-tory ones. Furthermore, with the rapid development of chinese iron & steel industry, the comprehen-sive recovery of these ores is becoming more and more important. The tin, zinc-containing complex iron ores are typical polymetallic and intractable ones, and great reserves of them are found in China. At present, they have not been efficiently utilized. In this paper, based on the investigation of basic physicochemical properties of the tin, zinc-bearing iron concentrates, taken from a mineral processing plant, the mineralogy reason that these concentrates are so intractable and refractory is found out, using advanced microscopic testing methods, such as optical microscope (OM), Scanning Electronic Microscope (SEM), X-ray diffrac-tion (XRD), etc. It is found that the symbiotic relationship of iron, tin and zinc metallic minerals are very complicated, and magnetite in the concentrate is closely symbiotic or enwrapped by fine cassi-terite and sphalerite. So it is difficult to separate tin and zinc completely from the iron concentrates by simple regrinding and physical separation method. This investigation provides theoretical guid-ance for developing new approaches for utilizing these concentrates.

Jan 1, 2014

By Pejman Oghazi

During the last decade the output of mining companies has increased rapidly. The key driver is the increase in demand for raw materials in the developing world, and thus this demand has driven up ore prices. From the time when the Raw material group (year 2000) started to introduced their index, it was set to 100 points. Today, year 2011, the index is over 400, which means that ore prices have quadrupled since then. Mine companies have to go deeper in the mines to access the ore bodies to increase the mine capacity and to be able to respond to the market. By going deeper in the mine, there will be new challenges that have to be considered. One of these challenges is how to handle the mine water that is produced in the mine. The water has to be moved to the surface in order to keep the mine from flooding, and this causes more challenges. One solution is to pump the mine water up to the surface without treatment; however, this causes considerable pump wear and the water will still require treatment on the mine?s surface. Another solution is to treat this water in the mine before pumping it to the surface. Metso Minerals has a system solution to treat the mine water, by separating the solids from the mine water. This system reduces the erosion in the pumps and will save many maintenance hours in the long term. One other option is to use the treated water in a closed circuit and reuse it in the process. This system can be divided into three steps: Firstly, a spiral dewaterer to remove the coarse solid particles. For the next step, lamella thickener is used to remove most of the solids, and lastly tube press to handle the sludge from the underflow lamella thickeners. Keywords: mine water, mineral processing, dewatering, separating

Sep 1, 2012

By Beatriz Pereda, Ana Clara Fonseca da Silva, Tiago Seixas Bittencourt

Reinforcing steel bars are usually specified based on mechanical properties with flexibility in chemical composition and processing. Most developments, in these steels, are normally focused on alloy and process design to reach minimum cost and conformity to specification. Processing routes using quenching and self-tempering (QST) and accelerated cooling are the most common. Microalloying with V and Nb have been used in rebar. When acicular constituents must be avoided, a combination of Nb microalloying with judicious control of cooling is one of the preferred options. Niobium can contribute to improvement in tensile properties through austenitic grain size control during hot working, precipitation hardening due to carbonitrides or clusters, and hardenability increase. In the present work the alloy design and development processes of a Nb microalloyed steel for rebars are presented. The designed steel has fulfilled the required specification and is under regular production. Austenitic grain size refining – when comparing with the “basic composition” normally used was observed, even without any change in the thermomechanical processing cycle. There are indications that precipitation hardening may also occur. Results indicate that Nb is a good alternative as a microalloying element in rebars.

Oct 1, 2019

By K. C. Corin, Z. G. Song, J. Y. Liu, M. W. Zhang, State Key Laboratory of Mineral Processing-BGRIMM, J. G. Wiese

"In the present study effect of grinding media on flotation of two mineral systems have been investigated, viz. sulphide minerals (including a pure chalcopyrite and pyrite mineral, and two different base metal sulphide ores), and oxide minerals (quartz, hematite and cassiterite). It was shown that mild steel media milling produced lower recoveries in the case of chalcopyrite and pyrite, as compared to the case of milling using ceramic media. For oxide minerals, the effects of using mild steel media as opposed to ceramic media were not as significant as was for the sulphides, although, after mild steel milling, at acidic pHs their recoveries were significantly reduced. For two base metal sulphide ores, viz. Nkomati and Dexing ores, the differences resulting from different milling media , although marginal, were opposite for each of these ores.For oxide minerals XPS showed that oxides and hydroxides of iron (e.g. FeOOH) adsorbed on the surfaces of the minerals. In the case of the Nkomati ore, adding Fe2+ or F3+ ions after milling with chrome steel media resulted in reduced talc (gangue) recovery, but increased water recovery and reduced concentrate grades. Further investigations are currently in progress to examine the Fe ions effect on the talc surfaces and froth properties.INTRODUCTIONGrinding of ores is necessary to liberate the valuable minerals from its gangues to allow for their selective recovery during mineral processing such as flotation. The grinding process inevitably involves contact of the ores with the surface of the grinding device and the grinding media. Accompanied by grinding, several phenomena can occur including the grinding medium wear, formation of precipitated species on the ore surfaces, chemical reaction, galvanic effects, changes in the Eh of solution, etc. There is a considerable body of literature on the differences observed in the flotation of various ores after milling using various grinding media. Laboratory studies have used balls or rods made from mild steel, ceramic, stainless steel or chrome steel to investigate the effects of different grinding media on mineral flotation. It is found that the interactions between the ore and the grinding environment can affect flotation separation of sulphide (Wei and Sandenbergh, 2007; Bruckard, 2011), oxide (He et al., 2014) and carbonate minerals (Song, 2009 and 2010). For example, mild steel milling produces relatively high concentrations of Fe ions in the pulp, affecting the recoveries of minerals compared to the case of ceramic media. On the other hand, the stainless steel media or chrome media are reported to be beneficial to the recovery of sulphides, when compared to the cases of using mild or carbon steel media (Rey and Formanek, 1960; Peng et al., 2003a,b; Huang and Grano, 2006; Bruckard, 2011). It is not clear, however, whether these Fe ions may affect the surface properties of the minerals involved or the general pulp/froth behaviour and hence their floatability. In addition, in the study of an low-S PGE ore carried out by Miettunen et al. (2012), forged media grinding in the CO2 atmosphere led to the highest Pt and Pd grades and recoveries, but the high chrome grinding media gave lower flotation recoveries than those using the forged media."

Jan 1, 2016

By R W. Wilson, A R. Branch, T S. Pooe

The original bulk air cooling system at this particular mine made use of two water chilling refrigeration machines to produce peak cooling of approximately 12 MWR with a downcast air temperature of about 7°C; however, as the shaft is not used for transporting personnel, the opportunity existed to supply more cooling to the mine by lowering the downcast air temperature. An ice storage facility has been constructed and provides a range of opportunities in operating the system: colder air temperature sent to the shaft, enabled by using near-zero degree water produced by melting ice to cool the air; electricity time-of-use management, by shifting electricity usage out of peak tariff periods; and increased peak cooling capacity, by melting ice while chilling water. Ice is created in the storage facility at night while the ambient air temperature is low and then melted to produce cold water when required by the cooling process. An ice dam was constructed and serpentine stainless steel coils installed where the ice is produced; one of the refrigeration machines was converted to chill a glycol solution to subzero temperatures to create the ice on the coils; a plate heat exchanger was installed to allow the glycol chiller to act as a water chiller as well; and a third spray stage was added to the bulk air cooler to utilise the near-zero water. This paper describes the thermodynamic design, construction and performance assessment of the new system, which is unique, novel and represents the state-of-the-art of this type of cooling system and energy management.CITATION:Branch, A R, Wilson, R W and Pooe, T S, 2015. Novel use of ice thermal storage for energy management on a mine refrigeration plant, in Proceedings The Australian Mine Ventilation Conference, pp 185–192 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By Peter Faust, Peter Hubbard, Kenichi Soga

The European Federation of Foundation Contractors (EFFC) and The Deep Foundations Institute (DFI) have set up a task group to compile a Guide for Working Platforms. The first edition of this Guide has been published in January 2020. The aim of the Guide is to provide reliable methods for design, testing and verification of working platforms for construction equipment, especially in the deep foundation industry where track loads can be excessive due to the nature of its operations. The Guide has identified areas where knowledge is limited. Actual track pressure and its distribution along the length of the tracks is still not well researched. Current recommendation provided in EN 16228-1 are believed to be overly simplified and may lead to conservative requirements for working platform thickness. This paper presents results of a series of field tests where the actual track pressure of a large drilling rig during operation was measured in real time together with the deformation of the working platform. Embedded, distributed fiber optic sensing (DFOS) at different depths throughout the platform allowed for a three-dimensional evaluation of the platform deformation throughout the entire operation. Results will help to develop more reliable recommendations for future safety requirements of working platforms for deep foundation equipment.

May 1, 2022

By Edward C. Clukey

A deep mixing method (DMM) foundation was selected by the Project Team for a very largeLNG facility in West Africa. As described in a companion paper, this foundation consists of alarge number of columns installed by mixing cement with in-situ soils. The foundations arearrayed as a variety of honeycombed type configurations which, if installed to desiredspecifications, can provide a robust foundation alternative. The foundation is capable ofdistributing loads and limiting settlements even if some of the soil in the columns is not fullymixed during installation. An important part of the overall quality assessment program,therefore, involved developing a testing program to verify the methodology. In addition theimpact of potential defects in columns on the overall foundation integrity had to be assessed.This paper describes some of the preliminary work done to establish the requirements for thequality assurance program. A key component of this program involved the samplingfrequency used to assess potential defects in the columns. To verify the column integrity 104-mm samples were taken continuously at a selected frequency through the 23 m longcolumns. The preliminary work described in this paper demonstrated that the appropriatesampling frequency depends on both the desired reliability level as well as the number ofdefective columns encountered during testing. Initial finite element analyses were performed to assess the extent that defects could occur incolumns within the honeycombed structure without adversely affecting the overall foundationintegrity. The results from this work demonstrated that the spatial location of the defects wascritical to properly assessing the foundation integrity. In addition to column sampling a load test was performed as part of the foundationverification process. The methods used to apply appropriate loads so that loads at thebottom of the columns approached design values are discussed in the paper. The results obtained from this preliminary study were then used to help develop a morecomprehensive assessment program, described in a companion paper, to determine therobustness of the DMM foundations for both the LNG processing facilities and a condensatetank.

By L. MacHue

Sulfur containing collectors have been shown over the years to function as strong, selective and non-selective sulfide mineral collectors. Unfortunately, the majority of the widely known sulfur based collectors are of low molecular weight, volatile and subsequently, possess an objectionable odor. Higher molecular weight sulfur based collectors (C9 and higher) are significantly less odiferous due to lower volatility and lower vapor pressures. In this study, a specific proprietary higher carbon number collector, Orfom® MC 37, was blended and used successfully to recover 2-3% additional molybdenum in a laboratory flotation system, when compared to a standard collector blend. Copper recoveries were also positively affected. Further testing is required to give additional conditions favorable to increased copper and molybdenum recoveries, but indications at this time show the proprietary sulfur based collector blend to be a selective collector of molybdenum, while providing a significant increase in copper recoveries.

Jan 1, 2010