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By B. H. Kim

The use of a 25.4 mm diameter water-only hydrocyclone for separating fine-size (-150 µm), high-density (>4.5 g/cc) particles from similar-size, lower-density (2.65 glee) particles was investigated. It was found that a single-stage separation recovered nearly 90% of the heavy minerals (7.0 g/cc), while achieving a volume reduction of about 70%. The use of dense medium in a single stage improved volume reductions to 90% at similar heavy mineral recoveries. In addition, computer simulations of a three-stage circuit were performed, which showed that recoveries approaching 97% with volume reductions of 95% were possible.

Jan 1, 1998

By A. Vien

A major thrust in Industrial automation over the past few years has been the exploration and incorporation of higher level (supervisory and optimizing) control strategies aimed at more fully exploiting the existing control system infrastructure. There is little doubt that this is worthwhile pursuit, however, one must not lose sight of the maintenance and development requirements of the basic control system. Statistics on loop performance indicate that this too is an area of considerable potential. In this paper the authors look at some of the less elegant, but arguably equally important issues in mineral processing plant control. The focus is on controller structures, loop tuning, sampling, filtering, and some of the other principal components of the regulatory control foundations. In many cases significant improvements In control performance can be achieved by getting back to the basics.

Jan 1, 1998

By A. V. Yevdokimov, Ye. V. Bogorodsky

The paper presents the results of the research on the development of gravity concentrates processing technology (gold grade is from 50 g/t to 1 kg/t and over) using intensive cyanidation with gold recovery to pregnant solutions followed by precipitation of metals from them using various methods. Test work and pilot plant results confirm that a new developed hydrodynamic regime provides an efficient treatment of gravity concentrates of polydisperse composition without their grinding and preliminary desliming. The resulting pregnant and washing solutions are amenable to metals recovery using electrowinning, cementation onto zinc dust and CIS. Cone plants with a lower ball valve for cyanidation of unground gravity concentrates developed by IRGIREDMET JSC have been successfully tested at a number of Russian operations. Currently, a modular plant equipped with gold electric precipitation from pregnant solution unit is successfully operated at a Russian gold processing plant. Cyanidation of the resulting high-grade gravity concentrate is carried out at the concentration of 8-10 g/L NaCN and 10 g/L NaOH. Gold recovery to the solution is 97-98%. Electrowinning is carried out in flow cell GNC-40M. In this case, the residual gold concentration yield is 0.3-0.5 mg/L. Also, a modular plant for relatively low-grade middlings (50-100 g/t Au) of gravity concentration has been introduced. The concentration of NaCN and NaOH is 2-3 g/L and 1.5-2 g/L, respectively, during leaching. This plant is equipped with a unit for gold cementation from pregnant solution with zinc dust. This cementation unit is of original design. It is made in the form of a filtering device and is composed of several layers of carbon fiber which contacts with zinc powder. The residual gold concentration yield from a cementation unit is less than 0.1 mg/L. Gold recovery is 93-97%. In 2017-2018, the introduction of intensive cyanidation modular plants to gravity concentrates will be planned at new projects of Russia and the CIS.

Jan 1, 2018

By I. Nakatsugawa

Chemical conversion coating is a process to create thin oxide/hydroxide film containing several inorganic/organic compounds by way of chemical deposition reaction. In case of the application to Mg mobile electronic housings, the film should possess a good electric conductivity while keeping adequate corrosion resistance and working as a paint base. The use of toxic/hazardous chemicals is strictly prohibited from the environmental aspects. This paper describes the recent trend of conversion coating used for Mg electronic housings and analyzes critically from the point of surface technology. The importance of cleaning process and understanding of surface microstructure are particularly emphasized with several experimental results.

Jan 1, 2006

By M. D. Monroe

Getting the best match between truck and haul road requires examination of many factors and their effect on the bottom line. Most mines use a bottom line measure based in some way on cost per ton of material moved. This measure focuses on the two components of truck haulage cost per ton: productivity (or performance) and operating cost. Productivity can be measured or predicted for specific tasks using either field measurement or modelling. Individual tasks can be combined to provide a larger scale, longer term net figure for total mine output. True cost is more difficult to capture as they are time and task oriented and can be influenced by a summation of factors over a truck lifetime. For example, "allocated" costs, such as owning (depreciation) and some repair costs, are spread over long periods of time. Other cost, such as fuel and tires can be tied more directly to certain tasks such as fuel and tire cost. This paper focuses on the more direct, task-oriented factors that affect truck productivity and cost.

Jan 1, 1992

By Anand Bhagwat

Surface control can prevent the falls of ground between primary roof support systems and rib support. Using existing industrial products, and adopting them for mining applications, has historically attained surface control in underground mining. However, the latest innovative solution, a revolutionary wire mesh product, is designed specifically for underground mining applications jointly by Bekaert and Orica. This knotted wire mesh, FlexKnot? 2500 and FlexKnot? 3500, uses smaller gauge, higher tensile strength wires, than a chain link fence or welded wire mesh. The higher tensile wire enables the mesh to achieve greater ultimate load-bearing capacity, with significantly lower overall weight. Test results, obtained at the National Institute for Occupational Safety & Health (NIOSH) Mine Roof Simulator facility, illustrate the comparisons of the new FlexKnot with traditional 8- and 10-gauge welded steel mesh. The FlexKnot is superior in deflection, load-bearing capacity, and stiffness?categories that are critical in achieving safer surface control. It also offers enhanced corrosion resistance because of the galvanized coating applied on the individual wires prior to the knotting process. Case studies from underground coal mine installations confirm that FlexKnot has the ability to significantly reduce installation cycle time and to minimize use and repetitive manual handling of individual mesh panels. An added advantage is the ability to supply FlexKnot in rolls for quick and easy handling for either rib or roof support application. When using rolls, the bolter can install the entire roll with one continuous forward motion, unlike the wasteful back and forth travel for mesh panel.

Jan 1, 2014

By Greg Yuriy

Over the past two decades, Vale Canada has used discrete-event simulation in a key role to support many underground mining studies. Traditionally, general purpose simulation software was developed for manufacturing and service applications. Not until recently have Mine Designers and Simulation Specialists been able to model the dynamics of underground mining scenarios without extensive manipulation of the inherent tools and entities contained within these simulation environments. This paper discusses Vale Canada?s past experiences with a variety of simulation software, describing model development methods and highlighting some of the lessons learned. The paper concludes with a review of recently considered software and provides a framework of desired attributes/functions for modeling mining scenarios.

Aug 1, 2013

By Juan Francisco Mori, Miguel Ángel Aucapoma, Pablo Zevallos

En este artículo se describe el prototipo de un equipamiento instrumentado digital cuya función es monitorear la condición de los techos de los socavones para evitar que se produzcan accidentes por desprendimientos generados por el debilitamiento de las estructuras que sostienen los techos, debido al corrimiento de las estructuras del macizo rocoso. Básicamente el sistema informa mediante la activación de alarmas pre-configuradas al interior de mina, con el propósito de prevenir y evacuar al personal.

Apr 30, 2020

By G. B. Abaka-Wood

"The versatility of froth flotation has made it vital in the beneficiation of rare earth elements (REE) minerals from either high or low grade ores of complex mineralogy. There has been a significant increase in the tonnage of rich iron oxide tailings obtained from extraction of primary commodities such as copper and gold in Australia, which have been identified to have very low grade rare earth oxides (REO) (= 1%). There is a vast knowledge gap in the upgrade of REO from such tailings. The aim of this research is to investigate the feasibility of the use of fatty acids for the upgrading of REO from selected iron-oxide rich tailings. Two forms of fatty acid collectors (oleic acid and sodium oleate) were employed in this investigation. Bench scale flotation tests were carried out using a Denver D-12 cell.The effects of pulp pH, fatty acid dosage, particle size distribution (-150 +75 µm, -75 +38 µm and -38 µm) and conventional depressants (sodium silicate and starch) dosage on flotation recovery of REO were investigated. A comparison of the flotation results indicated that sodium oleate was the more efficient fatty acid for REO flotation at all the pulp pH investigated. The flotation performance is demonstrated to be particle size-dependent. The results on the effect of depressants dosage indicated that both sodium silicate and starch were unselective in reducing the recovery of hematite (Fe2O3) and quartz (SiO2) with corresponding decrease in REO recovery. Generally, Fe2O3 and SiO2 formed substantial contents of the flotation concentrates obtained, both in the absence and presence of depressants, which indicates liberation is a major challenge in achieving selective REO upgrade and recovery.The flotation tests carried out on the iron-oxide rich tailings suggest the possibility of REO upgrade using fatty acids, although particle size distribution and minerals liberation are key limiting factors in achieving selective REO upgrade and recovery."

Jan 1, 2018

By Ilmar J. Martens

The statistical information and cost data used in this report has been made available by NICKDATA INC. Since 1982, NICKDATA INC. of Toronto, Canada, has produced an annual comprehensive nickel industry cost study. Up to date information on 22 mines, 21 smelters, and 16 nickel refineries representing 30 nickel production operations in 17 countries are included in the computerized cost analysis. The report is compiled from information obtained through regular annual visits to major nickel operations and continuous monitoring of information on all nickel producers. The 1984 report which was completed this summer, reveals drastic changes in the nickel industry cost structures.

Jan 1, 1984

By W. Y. Liu

A sulfate reducing bacteria strain (named SRB-A) is isolated from sanitary wastewater by using anaerobic technology of Hungate. The studies of physiological, biochemical and phylogenic of the isolated strain are carried out. The colonies of the strain are circle. Cells that are slightly curve, rod-shaped with the size of 1.0~3.0µm in length and 0.8~1.0µm in width. The optimum temperature for growth of the organism is 30~35°C. The optimum pH for growth is 7.0~7.2. Strain SRB-A can use sodium lactate, sodium citrate, sodium acetate, ethanol and acetone as electronic acceptor but can not use glycerol, glucose, sucrose and sodium oxatate. The isolated strain reduces sulfate, sulfide, sulfur, DSMO and FeCl3, then nitrate and nitrite can not be used. The strain has higher tolerance of NaCl, and the optimum growth occurs in the presence of 5%~8% (w/v) NaCl. The result of 16S rDNA sequence analysis indicates that the isolated strain SRB-A is the most similar to Desulfo-vibrio halophilus, and the level of the similarity was 98.4%. The isolated strain has a stronger ability to reduce sulfate, and the level of sulfate reduction reaches about 90% at pH 7 in the liquid medium. 0.6 to 0.8 is the optimum COD/SO42- in the medium for the isolated strain to show better ability to reduce sulfate. At pH 2.5 the level of removal of Cu2+ reaches 96.3%. Under the condition of pH 3.5, the level of removal of Zn2+ reaches 92.6%. When the value of pH reaches about 7, the Fe3+ is precipitated by the formation of Fe(OH)3, and Fe3+ is removed up to 89.4% at last.

Jan 1, 2014

By D. M. Thayer

Dry magnetic separation of feebly magnetic minerals and wet magnetic separators suitable for highly magnetic minerals have been commercially utilized for a number of years. The beneficiation of magnetic taconite ores by conventional, low intensity magnetic separators in combination with flotation is well established technology (1). However, over the past decade much effort has been expended in developing techniques for the upgrading of feebly magnetic oxidized iron ores (2,5). Such research and development have been stimulated by the limitations of the above-mentioned techniques in application to ores containing fine material; for example, ores requiring fine grinding for liberation or slime-forming ores such as the oxidized taconites or semi-taconites. Wet separation has allowed the reduction of the minim particle size that can be effectively treated from that allowable for high intensity dry magnetic separation. Consequently, the development of high intensity wet magnetic separation methods has received much attention in the search for an effective method to treat the weakly magnetic minerals. Recently Lawver and Hopstock (5) have provided an excellent review of the state of know- ledge of this technology. In addition, a valuable compendium of available laboratory and commercial devices is included. Nonetheless, the feasibility of the use of high intensity magnetic separation in a particular application is largly empirical in nature and requires experimentation to chazacterize the response of a particular ore. The purpose of this paper is to assess the incorporation of high intensity magnetic separation for the beneficiation of a non- sliming specular Michigan hematite. Particular attention is focused on the existence of a lower limit of particle size that can be treated effectively and is inherent in the use of these techniques. Additionally, a rationalization of various models presented in the literature is attempted.

Jan 1, 1979

By M. C. Ruiz

In the present study, the size distribution, Fo(v), of organic drops produced in a continuous-mixing vessel has been determined experimentally for various conditions. The organic phase used was a 1: 1 mixture of a salicylaldoxime (LIX 860N-IC) and a ketoxime (LIX 64-IC) in an aliphatic diluent (Escaid 103). The aqueous phase was a copper sulfate solution. The results indicated that an increase in stirring speed, extractant concentration, and pH produced smaller drops. The effect of the stirring speed was the most significant, decreasing the average volume of drops by 57 % for a change from 300 to 400 rpm. On the contrary, an increase in the dispersed phase fraction, copper sulfate concentration, and retention time produced larger drops. Changes in temperature from 23 to 30°C did not affect significantly the drop sizes. In all cases, the experimental drop size distributions could be accurately represented by a lognormal distribution.

Jan 1, 2001

By Charles L. Kimbell

World political events that occurred subsequent to yearend 1989 but that bear heavily on the global mineral industry have been of such significance that they cannot be disregarded, and certainly they contribute to any type of "outlook?. However, to write of them simply as "forecasts" in an "outlook" section of this study would be to unjustly pretend to status as prophets. Thus, this section covers events that have occurred not as predictions but rather as history. The section also includes an element with some broad statistical information, but this is included last rather than first for two reasons: the information is subject to considerable re- vision as additional data become available and as preliminary returns are corrected; and the authors view it as less important than the events that govern the statistics. The Near East and the Crisis There.- Of all 1990 political events influencing the world's mineral industry, the Iraqi invasion of Kuwait and the remarkable events that followed this aggression must head the list. The almost immediate imposition of economic sanctions, involving embargoes on shipment of virtually all goods into and out of Iraq, caused severe dislocations in the production and trade of mineral commodities, not only within the region itself, but with a ripple effect, into other world areas as well.

Jan 1, 1992

By S. Dawson

The Republic of South Africa has become a major producer of opencast coal in recent years. Opencast production commenced in 1970 and by 1977 some 10 million run of mine tonnes were being produced annually, Since then surface mine activity has increased to more than 60 million tonnes which represents approximately one third of the total annual South African? coal production. Whilst a substantial portion of this production is exported, the majority is used in the domestic market, The largest consumer, being the South?\ African Electricity Commission (Eskom), produces most of South Africa's electricity using coal fired power stations,

Jan 1, 1990

By Guangyuan Li

A 3-D block-spring model (BSM) has been developed for simulating the behaviour of jointed rocks. The model uses a discontinuous formulation and an iterative procedure to solve the large displacements in jointed and faulted rock masses. The 3-D BSM has been used to simulate mining excavations in jointed rocks around an open pit and underground settings. The applications have demonstrated that it is a practical tool to solve complicated problems of rock mechanics in civil and mining engineering. This model has recently been modified to incorporate complex geological conditions, such as underground water flow (seepage), unstable blocks and the time-dependent behavior of backfill materials. To demonstrate the capability of the 3-D model this paper presents the fundamentals of the 3- D BSM and its application for open-pit mining. A complete computer package BSM3D has been developed based on the 3-D block-spring model. The package consists of a solving engine for numerical analysis and a Windows based processor for mesh generation and results display. The multi-functioned pre-processor provides tools and menus to help users setting up models easily and conveniently. The fully featured post-processor allows users to view the results in different windows and orientations. The graphical results include contours, vectors, animation of rock movement, and the failure state of the rock structures.

May 1, 2001

By C. Allen, V. Hensel, J. S. Stachulak

"Vale has been actively evaluating new technologies to curtail diesel emissions. This paper discusses the selection, installation, operation, and evaluation of the MANN+HUMMEL SMF®-AR diesel particulate filter system to reduce diesel particulate matter emissions in underground mines. The system uses a sintered metal filter element, an iron fuel-borne catalyst with an onboard dosing system, an electric heater that uses onboard power, and a sensor-based control unit. More than 6,000 h of testing demonstrated that the system represents a breakthrough in the successful control of soot emission from light-duty vehicles with differing soot emission levels, exhaust temperatures, and duty cycles.RÉSUMÉ La compagnie Vale évalue activement de nouvelles technologies pour réduire les émissions de diesel. Le présent article discute du choix, de l’installation, du fonctionnement et de l’évaluation du système MANN+HUMMEL SMFMD-AR de filtrage des particules de diesel pour réduire les émissions de particules de diesel dans les mines souterraines. Le système utilise un élément filtrant en métal fritté, un catalyseur à base de fer dans le carburant avec un système de dosage intégré, un élément de chauffage électrique qui utilise l’alimentation incorporée et une unité de contrôle avec un capteur. Plus de 6 000 heures d’essais ont démontré que le système représente une avancée pour réussir à contrôler les émissions de suie des véhicules légers avec différents niveaux d’émission de suie, différentes températures d’échappement et différents cycles opératoires."

Jan 1, 2015

By K. Soldenhoff, D. Wilkins, E. Ho

In the processing of rare earth ores, a pure, mixed rare earth chloride solution is usually produced and used as the feed to solvent extraction circuits to separate the individual rare earths. Cerium(III) may be separated from the other rare earths by oxidising it to cerium(IV), which precipitates as cerium(IV) hydroxide in chloride liquors. This oxidation step may be inserted either before rare earth separation by solvent extraction or between solvent extraction circuits. Although oxidation of cerium by sodium hypochlorite has been known for many years, detailed conditions for oxidation are not readily available. The effect of hypochlorite addition, temperature, pH and cerium concentration on oxidation of cerium(III) from synthetic solutions was investigated

Jan 1, 2014

By U. Dmitrakova, G. Sedelnikova, D. Kim, E. Savari

"The paper presents the results of research on the development of gold and silver extraction technology from refractory gold sulphide flotation concentrate of one deposits of Nord-East of Russia. The concentrate is due to the complex mineral composition. Gold and silver are finely disseminated in sulphide minerals (arsenopyrite and pyrite partially oxidized by 7-11%). These are characterized by high content of silver 219 g/t and sulphide sulfur 32%, the presence of poorly soluble silver minerals (silver sulfosalts, fahlore, finely dispersed hypergenic acanthite in iron hydroxides and jarosite, etc.), and impurity minerals capable of interacting with cyanide (pyrrhotite, marcasite, nonferrous sulphides) and causing higher than normal cyanide consumption. Pretreatment of refractory sulphide concentrate by biooxidation using a mixed association of mesophilic and moderately thermophilic bacteria at a temperature of 36-40 °C for 120 hours oxidized arsenopyrite by 97.5%, pyrite by 93.5%, unlocked refractory gold, and generally oxidized the minerals absorbing cyanide and oxygen before cyanidation. Further oxidation of these minerals-absorbents was facilitated by the aeration in calcareous medium of the solid biooxidation residues of the concentrate. Sorption cyanidation of the solid biooxidation residues with addition of lead (II) of recovered 91.2% of gold and 82.9% silver from biooxidation residue, compared with 80.1% and 46.6%, respectively, for sorption cyanidation without the preceding biooxidation step. Biooxidation of the concentrate prior to cyanidation improves the recovery of precious metals, especially silver, and significantly reduces cyanide consumption from 18.7 kg/t to 3-5 kg/t of concentrate. INTRODUCTION Biooxidation of gold sulphide concentrates using acidophilic microorganisms has been successfully applied worldwide (van Aswegen et al., 2007; Gericke et al., 2009; Sovmen et al., 2007; Sovmen et al., 2009). At least 15 full-scale plants for tank biooxidation of sulphide concentrates are presently in operation, and the construction of new ones is planned (Bulaev et al, 2015)."

Jan 1, 2018

By K. Awuah-Offei, A. U. Rehman

"Information diffusion potential of a social media user affects how quickly information about a mineral project can diffuse through that user. If management can use social media and network analysis, in community engagement program, to understand how fast and how far information will diffuse to communities and followers of particular social media users, it can selectively focus on the most influential users. This paper proposes a method to examine the information diffusion potential of social media accounts. The work uses Gephi, an open source software, to extract and analyze data from different Twitter handles to predict their information diffusion potential. The work uses case studies of real Twitter users (e.g. mining news organizations and bloggers) associated with mining to illustrate the approach. The case study results show that there are significant disparities in information diffusion potential that will demand selective attention. This research will help mines develop effective social media engagement strategies. INTRODUCTION The mineral industry provides raw material for industrial activity to support our society (Martens and Rattmann, 2001). Mines have changed conventional mining practices to sustainable ones because of the negative impacts of mining and increased public awareness (Wang et al 2016). The concept of sustainable mining is getting mature as stakeholders (e.g., governments, investors and host communities) are getting involved in mining projects (World Economic Forum, 2014). The failure of mining companies to address the demands of these stakeholders might result in failure to acquire social license to operate (Thomson and Boutilier, 2011). The social license to operate (SLO), if granted, is mutually beneficial to all stakeholders. Mines prefer being granted SLO and keeping it to avoid any kind of social unrest due to their operation (Prno, 2013; Moffat and Zhang, 2014). Mining communities can grant different levels of SLO; ranging from withholding SLO to psychologically identifying with the project (Joyce and Thomson, 2000; Thomsan and Boutilier, 2011). Most of the previous work to understand community perceptions and SLO in mining is generally qualitative (ICMM, 2012a; Thomson and Boutilier, 2011; Prno, 2013; Moffat and Zhang, 2014; IFC, 2014). In particular, there is limited work on how community perceptions change over time due to information diffusion (Boateng and Awuah-Offei, 2017). However, SLO changes with respect to time (Yates and Horvath, 2013), which can result in risks that are not easy to predict. Mine managers and engineers have a desire to understand these changes so as to mitigate these risks (Que and Awuah-Offei, 2014; Que et al., 2015)."

Jan 1, 2018