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By K. Wood, R. McIvor, P. Blythe, M. Lavallee

A new analytical approach for characterizing and improving the performance of ball milling is presented. Individual ball mill circuit design and operating variables can be related to overall circuit performance through two distinct parameters for classification and breakage. The ball mill circuit functional performance equation is presented.Total mill x Classification x Test specific x Grinding power draw system efficiency grinding rate rate ratio= Production rate of new product size materialExamples from industrial plants and applications in the research and development field are discussed.

Jan 1, 1990

By B. A. Peppley

The current most common method of hydrogen production for fuel cell systems, including SOFC systems, is autothermal reforming. Autothermal reformers have a number of advantages including fast start up and load following and ease of control. However, there are a number of problems inherent with the addition of air into a system connected to the anode feed such as dilution of the fuel with nitrogen and the potential for oxygen to reach the anode chamber directly. Pure steam reforming, which does not involve air addition, provides a richer fuel mixture to the SOFC anode and is inherently safer than autothermal reforming. Although in theory pure steam reforming can be shown to provide these advantages, a number of technical problems need to be overcome before such a system can be practical. In particular, issues such as catalyst degradation due to poisoning and thermal sintering, coking, as well as fuel-steam mixing need to be addressed. Experimental results from a prototype reformer will be presented to illustrate a number of these points. This paper will compare differences in system efficiency, safety and complexity between autothermal/SOFC systems versus a steam reformer/SOFC system. A system simulation will be utilized that is able to account for material and energy balances for a SOFC power generator operating on diesel fuel. The requirements for improved catalysts will be discussed and an analysis of the potential benefits of sulfur tolerance and lower temperature activity will be considered.

Jan 1, 2005

By S. C. Ells

Introduction An investigation of the bituminous sands of Alberta was begun by the Mines Branch, Department of Mines, in 1913. This investigation was interrupted during the period 1916-19, but was resumed in 1920. Work completed in October 1924 has included detailed topographical surveys of extensive areas, examination and sampling of principal outcrops, the mining of trial shipments, laying of demonstration pavements, and a study of methods adapted to the recovery of hydrocarbons from the crude bituminous sand. Bituminous sand consists, for the most part, of clear quartz grains, cemented together by petroleum residuum or bitumen. In form the quartz grains are most irregular, varying from sharply angular to smooth, waterworn shapes. The bitumen has a specific gravity of 1.018 and has a penetration of 9.00 mm. (77° F. 100 grams 1 sec.). The percentage of bitumen associated with the sand varies from 5 to 25 per cent. A large tonnage is available in which the percentage of bitqmen is 15 per cent or over. Production Up to the present time, production has been restricted to requirements for experimental .and demonstration work. The total quantity shipped for such purposes has not exceeded 750 tons.

Jan 1, 1925

By A. McLean, L. Gao, Z. Shi, Y. D. Yang, K. Chattopadhyay, G. F. Zhang

Levitation melting of metals is one of the emerging applications of magnetic and electric fields in liquid metal refining. The varying magnetic field generates induced current inside the metal droplet and leads to the Joule heating effect and Lorentz force against gravity. This contactless process can avoid contamination from the crucible and can be used to produce high-purity materials. Visualization of the levitation melting process is difficult, and thus generally investigated by mathematical modeling. In the present study, a three-dimensional mathematical model of metal levitation was developed using finite element method for proper understanding of the levitation process. The effects of harmonic magnetic field frequency, coils power input, and sample size on levitation nickel droplet were investigated. Temporal evolution of temperature fields were predicted directly though the model. Levitation and balance condition of the droplet were investigated as well.

Jan 1, 2015

"Virtual reality, a 3D computer-generated environment, has become a recognized delivery system for many forms of education. This paper describes the application of virtual reality to mineral processing education. An interactive mineral processing visualization module developed at the University of New South Wales, Australia, provides users with an overview of a base-metal concentrator and details about how the mined ore progresses through stages in processing. The module also involves developing instructional based plant layouts and flowsheets in the virtual environment. These assist the user in understanding the essential components of the base-metal concentrator.RÉSUMÉ La réalité virtuelle (RV), un environnement en 3D généré par ordinateur, est devenue un système de prestation reconnu pour diverses formes d’éducation. Cet article décrit l’application de la réalité virtuelle à l’éducation dans le domaine de la minéralurgie. Un module interactif de visualisation du traitement des minerais développé par l’université de Nouvelle-Galles du Sud, en Australie, offre aux utilisateurs une vision d’ensemble d’un concentrateur de métaux communs ainsi que des détails concernant la progression du minerai extrait à travers les différentes étapes de traitement. Ce module implique également le développement de schémas de réalisation et de traitement didactiques dans l’environnement virtuel, lesquels schémas aident les utilisateurs à appréhender les composantes essentielles d’un concentrateur de métaux communsINTRODUCTIONVirtual reality (VR) is the creation of an artificial environment that is experienced through sights and sounds provided by a computer (Squelch, 2001). The simulated environment is achieved through technologies such as 3D graphics, audio feedback, and special peripheral devices to produce interactive environments.Virtual reality has been used in diverse fields including medicine (Riener & Harder, 2012), entertainment (Hsu, 2011), military (Manojlovich, Prasithsangaree, Hughes, Chen, & Lewis, 2003), manufacturing (Zimmermann, 2008; Jiang, 2011), and chemical processing (Squires, Andersen, Reklaitis, Jayakumar, & Carmichael, 1992; Schofield, Lester, & Wilson, 2005). Virtual reality is also becoming the recognized delivery system for education in many fields, including engineering (Bell & Fogler, 1996, 1998; Shin, 2002). For example, VR laboratories have been designed and developed to teach users fundamental features of heterogeneous catalytic mechanisms and absorption columns (Bell & Fogler, 1995), the multi-phase and multi-component blast furnace iron-making process (Babich & Senk, 2009), and to guide users to identify various safety measures while working in a real laboratory (Bell & Fogler, 1996)."

Jan 1, 2017

By Randolph A. Pax, Brian Cornish

The operation of grinding mills in an ore processing circuit is supported by monitoring the input and output variables. These can include the feed ore size distributions, ore feed and water addition rates. The outputs can include the discharge undersize density, oversize tonnage rate and the P80 of the discharge. The grinding mill performance is judged by the power draw, recycle rates and discharge grind size. Conditions inside the mill are inferred from loads cells or bearing pressures and past histories. An overall noise value is sometimes used to evaluate the load as well as the occurrence of excessive impacting of steel balls onto the liners/lifters of the mill. This paper presents results of the internal behaviour of a mill using non-contact stationary microphones located close to the mill outer shell (Pax, 2012). The noise generated by a mill can be attributed to a number of events that occur inside these mills and suitably analysed can provide real-time determinations of in-mill behaviour and can provide powerful insights into the operation of the primary comminution tumbling mills. The acoustically determined signals including a specific 'steel' signal, water hold-up, integrated area together with a classification of impact events. Specific results from case studies will show information of the trajectories inside a mill, steel to rock ratio as well as rheology effects. By incorporating a self-consistent understanding methodology for the in-mill processes from an array of microphones, the information can be used to diagnose the dynamic conditions inside a mill.

Jan 1, 2016

By Nick Vagenas

"Loading and transportation are important activities of the mining process. Automation of these activities in underground hard rock mining has been discussed for a long time. This paper deals with the performance evaluation of a prototype automatic Load-Haul-Dump (LHD) vehicle (a 7-ton GHH LF LHD model) operating in Zinkgruvan mine, Sweden. The purpose of the data analysis is to evaluate the operational and maintenance characteristics of the automatic LHD system in the mine. Graphical and numerical methods have been used for the statistical analysis of the data. IntroductionDuring the past years, the idea of integrated automation and tele-operation on Load-Haul-Dump (LHD) machines (Fig. 1) has attracted considerable interest in the Swedish mining industry. This is mainly due to the demand for improvement in the working environment and due to the rapid development of economic and reliable microprocessors for mining vehicles. Several advantages can be foreseen with the application of a Remote-controlled/Automatic LHD (RAL) system in underground mining. Some of them are (1)':• better utilization of working hours;• less interruption in production at shift changes;• better operational control of a fleet of vehicles;• improved safety; and• one operator may be able to operate more than one vehicle simultaneously."

Jan 1, 1993

By Lindsay A. Robertson

The long term management of acid generating tailings at mine closure is a common issue, however, management of ARD is significantly impacted by local conditions, including climate. Acid generating tailings, over time, will produce acid rock drainage (ARD) if left exposed to water and air, which both contribute to the sulphide oxidation process. The long term closure of tailings storage areas is a concern from both environmental and engineering perspectives, with long term acid generation and dam stability the main risks. Several approaches can be taken to minimize ARD from tailings facilities using cover systems. Three tailings facility cover case histories, in areas of net positive water balances, were investigated using unsaturated flow modelling software to determine the long term potential for limiting ARD by increasing saturation of the tailings and decreasing oxygen ingress. Each case study demonstrates the importance of integrating the tailings dam engineering into tailings cover closure design. Model predictions are compared to measured saturation levels to assess the accuracy of the calculations.

May 1, 2011

By W. Geslin

Backward extrusion process is a metal forming process, which limits the manufacturing?s extra thickness when compared with classical die forging technique. Because of a lack of alloy?s mechanical behavior knowledge, the basic strategy of design is as follow: ?Definition of a small scale blank ?Performing experiment in order to get useful process data ?Improvement finite element simulation conditions ?Development of the full scale blank forming process (design of tools,...) using the finite element simulation A comparison between the result of modeling and the experimental data has been done to validate the finite element simulation.

Aug 1, 2010

By Takashi Nakamura, Atsushi Iizuka, Yong Fan, Etsuro Shibata

Magnetic separation of precipitated magnetite as iron resources in copper slag is one of the potential effective ways to recycle the slag. It is preferable to convert molten fayalite slag after copper smelting process to magnetite slag via oxidation. With a TTT (Time-Temperature-Transformation) diagram, the crystal composition of the slag obtained after air isothermal oxidation could be estimated through a designed cooling path. The crystallization behaviors concerned with molten oxidation was studied for better understanding of the trade-off relationship between magnetite and hematite during molten heat treatment. Moreover, a brief consideration was implemented of the reaction mechanism.

Jan 1, 2014

By Pierre Choquet

"The whole work carried out both in situ and in laboratory by a research group of the West German collieries is presented. This work has led to a design method of steel arch supports for gate roadways that gives full satisfaction in this particular coalfield. The method accounts for mining depth, the mining system (advancing or retreating), thickness of the coal seam and other parameters.Full statistics are then given on gate roadway supports of the ECCS (European Community for Coal and Steel) coalfields. They were collected by the author in order to show that the West German method can be applied to other coalfields as the long wall systems which are generally being used are very similar. Design calculations are conducted for each coalfield's case. They show that the method would have been able to predict in most cases the support actually used.Utilization of the design method is recommended to the Cape Breton Development Corporation 's mine operators because mining conditions, even though different from European ones, present a number of similarities which make it possible to apply the design method to their particular case.This procedure might be profitable in mines facing support problems in their levels and for any planning of future projects"

Jan 1, 1986

By G Zahary

THE most acceptable approacl1 to analyzing rock behaviour, at the present time, is based on the application of principles of mechanics and strength of materials. Analyses have been made in which the criterion of failure is based on maximum stress (1) and on Mohr's rupture theory (2). If such analyses are to be carried out, the mechanical properties of the rock must be known within acceptable limits. Although an adequate correlation of laboratory test results with field conditions has not been established, test results have been published (3) on the basis of their comparative value. That is, test results may be useful for comparing the behaviour of different rocks under similar loading conditions or of a particular rock under different loading conditions. This study aims at establishing some of the mechanical properties of an andesite rock by testing specimens cut _from diamond drill core. Drill core (EX) was provided from run-of-mine drilling by New Dickenson Mines Ltd. and Campbell Red Lake Mines Ltd.

Jan 1, 1963

By Rocky (Yaokun) Wu

Rock burst is one of the biggest challenges to ground control in the mining industry. With increasing mining depth and mining scale, there are more and more industry requirements on yielding rock support. Since 2008, Jennmar has been conducting large scale research and development works to develop a technically reliable and cost effective yielding rock bolt. This paper introduces a new yielding rock support - Yield-Lok bolt. The bolt is characterized by the designed yielding ability to produce 150 ~ 250 mm of deflection at 8 ~ 10 metric tons (Mt) loads for every 16.4kJ energy input. Its performance characteristics are consistent through multiple and varying amplitude of impacts. In this paper, the design criteria of the bolt and the principle of performance are described, the dynamic testing results are discussed; and the features and application of the bolt are presented.

Oct 1, 2010

By Daniel D. M. Adams

In 2004, Rio Tinto started a major project to implement Mine Monitoring and Control (MMC) systems worldwide. A detailed selection processes was undertaken and migration to a standard system was started. Today systems are operating around the world and serve as the core of to many business processes. Implementations include highly union areas, large mines, centrally managed mines, and remote areas. Each implementation has unique challenges but all are working towards the common goal with common systems. This paper reviews two projects that Rio Tinto has deployed in diverse conditions. The projects are the Rossing Uranium upgrade from the original Wenco system to the common standard and Iron Ore of Canada?s general technology upgrade. Also discussed is the future of mining at Rio Tinto, specifically the drill automation projects, and how it is utilizing the common standard MMC systems.

May 1, 2010

By Hung-wei Liu, Kevin Plucknett

Early attempts to manufacture titanium aluminides using blended elemental powders, through powder metallurgical processes, have been obstructed due to serious swelling during sintering. Although the use of pre-alloyed powder can avoid this undesired expansion problem, there are limited commercial powder sources available. Therefore, in the present research, fundamental studies on the synthesis of dual-phase (? plus a2) Ti48Al intermetallic materials is undertaken, in particular assessing powder manufacture. In order to produce pre-alloyed powders, highly porous Ti48Al pieces are initially sintered from elemental Ti and Al powder blends, and subsequently pulverised into powders. The powder size is then further reduced by use of either dry or wet milling processes (i.e. shatterbox grinding, attrition, or ball milling). Among these methods, shatterbox grinding has shown the highest efficiency, with a slight mechanical alloying effect observed. The manufactured powder morphologies and phases, as well the sintered material, will be discussed.

Jan 1, 2015

By R. G. Gillies, C. A. Shook, W. H. W. Husband

"The current state of knowledge concerning pipeline transport of coal in water slurry form is summarized for the four categories: coal-water fuels, conventional fine coal slurries, coarse coals and stabilized mixtures of coarse and fine particles. Surface chemistry is of dominant importance for coal-water fuels and considerable progress in understanding the role of surfactants has been achieved in recent years. Little generalized research on the flow of conventional fine coal slurries has been done in the past 17years, although innumerable conceptual designs and feasibility studies have been undertaken. Coarse coal slurries are fairly well understood but the model which explains their flow requires more data to be established fully. Stabilized flow mixtures should probably obey the same model as coarse coal slurries but experimental results for stabilized mixtures have not yet been incorporated in a comprehensive theory.IntroductionPipeline transportation of coal in a water vehicle has been employed for many years in coal washeries. It has been used less frequently in hydraulic mining and thermal power station fuel supply systems. The suitability of coal for pipeline transport arises from its moderate specific gravity relative to the carrier fluid and the fact that throughputs are often large and steady over long periods of time."

Jan 1, 1990

"Dry crushing trials at pilot scale have shown that the IMPTEC Super-fine Crusher has the capacity to generate ultra-fine products from hard mineral assemblages presenting at either coarse or fine feed sizes. The super-fine crusher was introduced at the 27th International Mineral Processing Congress in Santiago Chile, with results from a range of duties, which demonstrated the crusher’s potentially expansive operating scope. This paper focuses on current preparations to progress the technology from pilot scale to commercial scale within a concrete production plant, where lead blast furnace slag will be crushed to ultrafine sizes to generate an active silica product for use as a supplementary cementitious material, which can replace Ordinary Portland Cement. A key objective of the operation is to demonstrate an economical route to reducing the cost of concrete production, improving concrete quality and reducing greenhouse gas emissions. The paper also highlights the potentially key contribution super-fine crushing can make to the long-term viability of iron ore beneficiation by simplifying comminution flow-sheets and reducing operating costs. There is every indication that the technology has the potential to feature universally in metalliferous and industrial mineral flow-sheets. INTRODUCTIONToday’s IMPTEC super-fine crusher is the successful end product of development work over 19 years and is the third particle size reduction device conceived, built and tested over that time. The concept evolved as engineering design progressively developed a mechanism capable of harnessing a highly efficient combination of fundamental particle breakage mechanisms. Early development trials at pilot scale indicated that super-fine crushing had the potential to establish a wet or dry, media free, low energy route to ultra- fine products from hard mineral assemblages. Having achieved some impressive results from open circuit pilot tests on fly ash and granulated blast furnace slag it became clear that the cement industry may well provide opportunities to apply the technology commercially. Following expressions of interest from local cement and concrete plant operators, IMPTEC negotiated an agreement to undertake commercial trials with a SFC 350 super-fine crusher installed on site at a concrete supply plant in South Australia. Super-fine crushing scope was recently expanded following further expressions of interest from research groups involved in the processing of iron ores. Pilot trials are progressing in these areas."

Jan 1, 2016

By Z. Y. Liu

A local additional potential model (LAPM) was developed to illustrate the role of strain rate in stress corrosion cracking (SCC) of pipelines. According to LAPM, both density and mobility of the local active spots on the steel surface, i.e., dislocation emergence points, increase linearly with strain rate. Generation of such active spots introduces an additional negative potential locally, affecting the electrochemical reaction and, consequently, the susceptibility of the steel to SCC. Electrochemical corrosion measurements, slow strain rate tests and electrochemical hydrogen permeation test were combined to demonstrate the validity of LAPM to illustrate pipeline SCC in an acidic soil solution. It is found that a maximum of the SCC susceptibility occurs at strain rate of 10-6 s1, which is associated with an enhanced hydrogen evolution due to the local additional potential (LAP) effect.

Jan 1, 2010

By Mei-Yan Yang, Ltd. Yunnan Yuntong Zinc Co., Yong-Xiang Li, Xing-Zheng Dai, Hong-Liang Wang, Meng-Yang Huang, Peng Zeng, Guo-Feng Li

"The removal of iron asgoethite from the high iron bearing solutions generated in zinc hydrometallurgy using a strong airflow device was investigated. The influence of oxygen flow, copper ion concentration, temperature and reaction time on iron precipitation as goethite was studied. The optimum conditions were: oxygen flow 0.2-0.35m3/h, copper ion concentration 0.25-0.5g/L, temperature 80-90oC, zinc oxide powder neutralizing agent and a reaction time of5to 7hours. Under the optimal conditions, the Fe2+concentration was reduced to 0.025g/L after iron precipitation, and the goethite residue contained 38.7wt.%Fe. The SEM and XRD analyses showed that the iron was present as well formed FeOOH crystals in the iron residue, and the amount of iron sulphate was very low. Production practice shows that, when the average iron concentration in the feed solution was 11.61g/L and 4.08g/L after precipitation, the weight of iron removed was 1,439kg/day. When the average iron concentration in the feed solution was 14.51g/L and 2.73g/L after precipitation, the weight of iron removed was 2,454kg/day. This represents a ~70 percent increase in iron removal.INTRODUCTIONThe objective of iron removal is to produce a small volume of iron residue, and our industrial goethite process meets this requirement. The high Fe(II) solution in our reactor isoxidized/hydrolyzed to precipitate goethite and the precipitate is sent to a pyro metallurgical furnace for final residue treatment. Some literature discusses (DengYong-guiet al., 2008;Meiguang-guiet al., 2001;Zhongzhu-qianet al., 1980) research on iron hydrolysis; one of the reported rate limiting parameters was the low availability of the oxidant when using air and another was the inhomogeneous air distribution. There are two iron hydrolysis-goethite precipitation methods; the Electrolytic Zinc process (EZ) and the Vieille Montagne process (VM) (Lei Xiang, 2006; Xuguo-qiang, 2007;ZhaoYonget al.,2005). The EZ method hydrolyzes the Fe3+directly to FeOOH. The weakness of the EZ process is the low recovery rate of the associated minor metals. The VM method reduces the iron to the ferrous state and then oxidizes the Fe(II)to Fe(III),with simultaneous hydrolysis/precipitation of the Fe(III) as FeOOH. Before iron hydrolysis, the minor metals, such as indium, could be selectively precipitated, because Fe(II)requires a high pH for hydrolysis. So the VM method has a high recovery rate for the minor metals. There levant goethite precipitation reaction is:"

Jan 1, 2016

By M. Hozayen, E. S. Radwan, P. A. Nawrocki, A. Jebbouri

"A major geomechanical study was conducted for one of the UAE onshore oil fields with the purpose of studying reservoir rock properties and stress distribution, based on which a 3D coupled reservoir geomechanical model was built. This model was later used for wellbore stability analysis and for analyzing the effect of fractures on future reservoir production performance, including fracture deformation and permeability evolution occurring due to reservoir depletion and resulting changes in local stress field. The subject of this study was a complex fractured Upper Cretaceous carbonate reservoir characterized by high degree of heterogeneity, both vertically and laterally. Wellbore instability related drilling problems were encountered while drilling the wells in this field. The problems were mainly in drilling the horizontal wells, including breakouts and mud losses. Experimental results of laboratory tests are summarized in this paper whereas wellbore stability analysis and formulation of a 3D geomechanical model that was built for that purpose is summarized in a sister paper (Part II).A suite of tests reported includes tensile strength, uniaxial and triaxial compression and permeability under stress at simulated reservoir conditions. All tested rocks have been grouped into twelve test units and reservoir geology, rock types and challenges related to designing a viable sampling and testing program for a big reservoir are discussed first followed by sample selection criteria and details of the testing program. All test units showed brittle behavior at zero confinement and some samples showed similar behavior at low confining stresses. With confining stress increase, the behavior gradually turned to plastic but some samples showed features of ductile behavior even at low confinement.Obtained experimental data have been summarized in the form of strength criteria and correlations. The Mohr-Coulomb strength equations were obtained for each test unit and also for the averaged values. It was noticed that triaxial compressive strength (TCS) increases with decreasing porosity or increasing density but their influence on TCS is getting smaller with confining pressure increase. Good correlation of porosity and density with Young’s modulus, Poisson’s ratio, unconfined compressive strength (UCS), friction angle, cohesion and tensile strength has been noticed and there was an increasing trend between the confining pressure and TCS. Rock type (mud or grain supported) was not influencing the TCS as much as porosity and density and the two lithologies encountered affected TCS approximately in the same way. These results and correlations are summarized and explained in this paper. They were further used in the numerical modelling part (Part II) of this paper, Hozayen et al. (2015). It is also concluded that rock lithology is not a decisive factor and mechanical properties of tested rocks should be rather considered dependent on porosity and permeability. This helped greatly in reducing the number of tests that had to be performed."

Jan 1, 2015