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By R. C. Gilmore, J. McMack, G. E. Bogin, J. F. Brune, C. DeRosa

"Researchers at the Colorado School of Mines are designing and building a 1:40 scaled physical model of a fully operational longwall coal mine. The purpose of the model is to minimize the occurrence of methane explosion hazards by testing various ventilation strategies and determining optimal methane sensor placement throughout the longwall face. Fluid scaling factors were analyzed using Computational Fluid Dynamics software Ansys FLUENT™ at both full and 1/40th scales. Researchers were able to identify key scaling factors and subsequently developed suitable flow parameters that would maintain full scale accuracy of flow patterns in the 1/40th model. KEYWORDS Coal, Longwall, Methane, Explosion, Scale Model, Ventilation, Fluid Dynamics, Richardson, Gob, Porous INTRODUCTION Mine ventilation systems are a key component for ensuring a safe working environment by introducing fresh air from the surface and diluting explosive gases and hazardous contaminants. This holds true for longwall coal mines where the emission of flammable methane gas from the longwall face as well as the gob can create explosive mixtures of methane and air. Therefore, an effective ventilation strategy can help mitigate the potential for accidents within a mine. Developing an effective mine ventilation system (MVS) requires a detailed understanding of the physics of gas transport and how this relates to specific geometries and obstructions in the face. Researching this phenomenon requires the development of computational fluid dynamics models capable of simulating fluid flow and methane species transport that can be validated through physical experimentation. Unique site conditions determine ventilation layouts for every coal mine. Researchers have designed a 1/40th scaled physical model of a longwall coal face and adjacent gob that includes movable shield supports and a movable shearer with rotating cutter drums that can be adjusted to a variety of ventilation conditions. The proposed work will address the need for an improved Mine-wide Atmospheric Monitoring System (AMS), and provide the ability to link existing MVS models with AMS in real time. By accurately representing the coal face, the gob area and the mining equipment, gate roads and bleeder entries, the scaled model accurately represents all relevant structures, geometry, and dynamic conditions. A Plexiglas cover allows full optical access for sensor equipment as well as visual inspection of the fluid flow and species transport."

Jan 1, 2019

By Wei Huang, Anh V. Nguyen

"Potash flotation is an industrially proven success of flotation of soluble salts, but its collector adsorption mechanism remains elusive. In this paper, specific ion effects in NaCl-KCl flotation with carboxylate collectors were investigated. Flotation recovery and contact angle were determined as a function of brine composition of NaCl and KCl. The experimental results have shown that wettability of KCl and flotation of the soluble salts with laurate collectors were dependent on brine ion composition. Specifically, adding Na+ to brines decreased hydrophobicity of KCl crystals and their flotation recovery. Both KCl and NaCl could be floated with laurate collectors. However, flotation of NaCl was greatly enhanced by adding K+ to brine whereas flotation of KCl was significantly suppressed by the presence of Na ions. The decrease in KCl recovery upon adding Na+ is attributed to the counter-ion binding in the pulp. The flotation recovery enhancement of NaCl in the presence of K+ is explained by two effects: 1) increasing K+ concentration leads to a better dispersion of collector colloids in the pulp and 2) K+ enhances the collector adsorption at NaCl crystal surfaces. The water affinity matching rule can explain the specific ion binding behaviors and supported by the SFG spectroscopic results.INTRODUCTIONPotassium is an important fertilizer. Its primary source comes from potash ores, which are a mixture of sylvite (KCl), halite (NaCl) and many other complex double salts such as carnallite (KCl·MgCl·6H2O), alkali nitrates such as KNO3 and NaNO3, and sulfates-langbeinite (2MgSO4·K2SO4) with water-insoluble minerals such as clay and carbonate minerals. Previously, these salts were recovered with a lengthy hot leaching method, with further crystallization of potassium salts from saturated saline solutions. Selective flotation has been preferred since 1940s. Various collector adsorption mechanisms have been proposed soon after the industrial introduction of potash flotation. These include the formation of the insoluble compound model (Halbich, 1933; Singewald, 1961), an ion exchange model (Fuerstenau and Fuerstenau, 1956), a heat of solution model (Rogers, 1957), the surface hydration model (Schubert, 1988), the surface charge model (Roman, 1966; Miller et al., 1992), the interfacial water structure model (Hancer and Miller, 2000) and the colloid adsorption model (Leja, 1983; Burdukova and Laskowski, 2009). Most of the early exercises attempting to propose a unified rule on collector adsorption mechanisms can be seen as heroic endeavors due to the consideration of a vast number of salts in the pulp including alkali halides, nitrates, and sulfates, even the practically insoluble heavy earth metals. Additionally, several types of surfactants with different polarization features and alkyl chain length have been employed. As for the recent models, due probably to the preferential application of long chain amines as collectors in industrial potash flotation, most researchers are only devoted to collectors with low polarization features like amines and sulfonates (Hancer and Miller, 2000; Du et al., 2014). Collector adsorption mechanisms are therefore proposed based largely on a neglect of carboxylates as collectors. However, carboxylates remain an important collector type in soluble salt flotation systems where both salt minerals can be floated using anionic collectors and cationic collectors. Fatty acid type collectors are still one of the widely used collectors for soluble salt flotation and also one of the first to be applied on an industrial scale for the separation of potash ore (Hernáinz et al., 2003; Titkov, 2004). Here we examine some recent models that are relevant to our study to reveal a long neglected specific ion binding effects in potash flotation."

Jan 1, 2016

By D. Sammut, F. Houllis, J-L. Huens, J. Moyes

The Intec Gold Process has been developed as a halide-based alternative for the recovery of gold from refractory sulphide deposits. The halide medium allows sulphide oxidation and gold extraction to be performed concurrently at moderate temperature and atmospheric pressure sourcing oxygen from direct air injection. The dissolved gold is loaded onto activated carbon and stripped in a conventional Zadra circuit. High gold extractions have been achieved from a range of refractory gold concentrates at laboratory scale, which has led to a continuous locked-cycle pilot plant program. The pilot plant operated at >99% availability, with a maximum of 96.5% gold extraction from a concentrate containing 58.6 g/t gold. >99% of the dissolved gold was loaded onto carbon at up to 1% w/w, with no loss of carbon activity detected over five loading/washing/elution cycles. This paper describes the process and presents both laboratory and pilot plant results as well as economic data from two costing studies.

Jan 1, 2005

By P. J. Mackey

"The metal producing industries in Canada and in the U.S. in many ways owe their technical beginnings to Welsh technology. The first copper smelter in Canada started in 1849-50 with a Welsh reverberatory furnace and skilled furnacemen brought across from Swansea to operate the equipment1- The Rocky Mountain smelting industry began with the installation of furnaces resembling the Swansea smelters(2). It was only later that the North American industry developed newer and improved methods. This article briefly describes the metallurgical history of the Lower Swansea Valley, being that section of land stretching northward from Swansea along the banks of the River Tawe, and bordered by hillsides east and west of the river. The Valley has had a classic cycle of development and decline common to industrial areas of Britain which grew in the Industrial Revolution. Perhaps more than any other area today, the Swansea Valley represents a complete cycle of use from agricultural to the peak of industrial development through to decline and dereliction. The conditions which made the Tawe Valley attractive to certain industries were laid down nearly 300 million years ago with the Carboniferous swamps and forests which covered the area, later forming the south Wales coalfield. As a result of glacial action and the deposit of glacial outwater and alluvial gravels, the valley adopted the traditional configuration, with its rocky sides occasionally remaining exposed. Up to probably about the 16th century, the Lower Swansea Valley was similar in use and appearance to many other valleys in the region. From the 14th century, the natural oak woodland had provided a continuous source of timber to produce charcoal for iron making as well as for structural purposes. Agriculture was the main activity in the valley in this period, but it was likely that the farmers also mined small amounts of coal by way of ""bell pits"", and adits into the coal seams."

Jan 1, 1999

By Mark Freberg

"IntroductionThis chapter is intended to provide information on the operation and maintenance of several pieces of equipment used in heavy media separation. Most heavy media separation circuits, particularly those involving bath separators can be considered as high maintenance areas. Because of this the efficient operation and maintenance of these circuits is very important if the cost per ton of material treated is to be kept to an acceptable level.Heavy media separation (HMS), is a process used to separate particles of different specific gravities. Under laboratory conditions the ideal way to separate two types of particles which have different specific gravities is to suspend them in a heavy liquid which has a specific gravity between those of the two types of particles. Those particles with the lower specific gravities will float on top of the liquid while the higher specific gravity material will sink to the bottom. Given enough time and a sufficient volume of heavy liquid this process will be essentially insensitive to the sizes of the particles involved.Heavy media separation circuits make use of the same principles described above. The material to be treated is introduced into a mixture of finely ground solids, called media, and water which takes the place of the heavy liquid; the mixture of solids and water is known as medium. The separating force can be either gravity or centrifugal force. The type of solids used as media varies but it is usually a high specific gravity material such as magnetite, galena or ferrosilicon.Heavy media separation is used extensively in the cleaning of coal and to a lesser extent as a preconcentration step in base metal and iron ore operations."

Jan 1, 1989

By Georges Houlachi, Akram Alfantazi, Michael Mahon, Maysam Mohammadi

Corrosion resistance of the lead-based anodes directly influences the purity of the final product in the zinc electrowinning process. The anodic MnO2 layer that is electrodeposited on the anodes during this process can protect the anodes against corrosion. Sand-blasted anodes generate a uniform, adherent and shiny MnO2 layer, which gradually blisters and eventually sloughs off after several weeks. In this study, we attempted to develop a new method to stabilize the MnO2 protective layer on the anodes during the electrowinning process by providing suitable nucleation sites for electrodeposition of this layer. MnO2 particles (P80=40µm) were used as seed material for this purpose. Different techniques of galvanostatic and cyclic voltammetry polarizations, scanning electron microscopy (SEM) and atomic absorption spectroscopy (AAS) were employed to investigate the performances of the MnO2-seeded lead anodes. The experimental results showed that growth of the MnO2 layer is influenced by the MnO2 seed particles on the anode surface. The MnO2 layers electrodeposited on the MnO2-seeded lead anodes were uniform and strongly adherent to the substrate. This layer was more stable than those formed on the PbAg anode without MnO2 seeding. This could provide the anode with a higher level of corrosion protection. Moreover, formation of undesirable MnO2 mud in the electrolyte and the rate of manganese consumption were decreased when the MnO2-seeded lead anodes were polarized. These observations could be attributed to the different properties of the electrodeposited MnO2 layer on this anode in comparison with that formed on the PbAg anode.

Jan 1, 2016

"In the UK, Ireland, and Western Europe, the mineral resource and reserve reporting standard is the PERC Code, developed and maintained by the Pan-European Reserves and Resources Reporting Committee, which is a standing committee set up under the auspices of a number of professional organisations which include the Institute of Materials, Minerals and Mining (loM3), the Geological Society of London (GSL), the European Federation of Geologists (EFG) and the Institute of Geologists of Ireland (IGI) to develop a Pan-European reporting code. The PERC Code supercedes the old IMMM Reporting Code 2001 and is recognised by the UK securities regulators and stock exchanges.""FOREWORD1 The Pan European Reserves and Resources Reporting Committee (PERC) Code for Reporting of Exploration Results, Mineral Resources and Mineral Reserves (further referred to as 'the Code') sets out minimum standards, recommendations and guidelines for Public Reporting of Exploration Results, Mineral Resources and Mineral Reserves in the United Kingdom, Ireland and Europe. The history of development of this code is summarised in Appendix 4.This 2008 edition supersedes all previous editions of The Reporting Code and the IMM Reporting Code.INTRODUCTION2 In this edition of the PERC Code, important terms and their definitions are highlighted in bold text. The guidelines are placed after the respective Code clauses using indented italics. They are intended to provide assistance and guidance to users in interpreting the application of the clauses in the Code. The same indented italics typeface formatting has been applied to Table 1, and to Appendices 1 and 2 which form part of the Guidelines.3 The Code has been adopted by the Institute of Materials, Minerals and Mining (loM3), the Geological Society of London (GSL), the European Federation of Geologists (EFG) and the Institute of Geologists of Ireland (IGI), and is therefore binding on their individual members.Appendix 1 contains a table of generic terms and their equivalents, designed to avoid unnecessary duplication or ambiguity in the textAppendix 2 provides Rules of Conduct for Mineral Resource and Mineral Reserve estimators that should be considered in addition to the Codes of Ethics normally applying to members of professional institutions."

Jan 1, 2003

By Shanjun Mao

This paper summarizes current achievements of Digital Mining in China, puts forward the concept, framework and key technology of Smarter Mining, and finally points out that there is still a long way to go in order to acheive Smarter mining.

Aug 1, 2013

By N. Chow, W. McCombe, G. Remple, J. Nikkari, L. Nightingale-Mercer

Orano Canada Inc. (Orano) operates the McClean Lake mill in northern Saskatchewan, processing high concentration uranium ore, delivered in slurry form, from the Cameco operated Cigar Lake mine. This slurry is ultimately processed into the purified uranium oxide product known as calcined yellowcake. During the calcining process, sulphate (SO42-) entrained in the yellowcake undergoes thermal decomposition into sulphur dioxide (SO2). SO2 is a colourless gas that poses health and safety risks. Since 2016, an anhydrous ammonia dosing system was successfully added to the existing Venturi particulate scrubber system to provide efficient removal of SO2 from the calciner off-gas. Within the pH controlled scrubber solution, SO2 exists in a pH dependent equilibrium with sulphite/bisulphite (SO32-/ HSO3-). The presence of a significant fraction of reduced sulphite and bisulphite in mill solutions presents a hazard in downstream circuits. Should these solutions drop in pH, either through natural oxidation or inadvertent mixing with low pH solutions, the solution equilibrium will shift from SO32-/HSO3- in favour of SO2, resulting in the evolution of SO2 gas from any liquid surfaces. In 2018, Hatch Ltd. (Hatch) and Orano implemented a design change in the calciner scrubber system. Blowdown from this system is now treated in an oxidation pre-step utilizing hydrogen peroxide (H2O2) and anhydrous ammonia (NH3) for pH control, in order to convert the residual sulphite/bisulphite present in solution to stable ammonium sulphate product. This paper will detail some of the challenges and actions undertaken to minimize SO2 risk, culminating in the recent introduction of a novel system designed to oxidize sulphite/bisulphite and prevent mobilization from the calciner scrubber solution into other mill areas where there is the potential for acidification and SO2 release.

Jan 1, 2020

By N. Depountis, Th. Rondoyanni, N. Sabtakakis, K. Kavoura, G. Tsiambaos

"Some typical landslide phenomena in Western Greece, in terms of the geological composition and structure of the affected materials, induced by heavy rainfalls are thoroughly studied and analyzed. The studied cases involved composite landslides on Flysch and Neogene weak rock materials that constitute the most critical landslide prone geological formations in Greece. The studied cases named Platanos, Platanitis and Karya include representative landslide sites as regards to the geological composition and structure of the displaced formations. Thus: (a) flysch formation includes different lithological units as shales, marls, siltstones, sandstones and conglomerates and is closely related to the Alpine orogenesis, suffering intense past tectonic movements and (b) the Plio-Pleistocene sediments include clayey marls, marlstones and siltstones. The investigated landslides , affecting mainly transportation routes, are closely related to heavy rainfalls induced by extreme meteorological events and are controlled by active fault tectonics. Long term movement monitoring using borehole inclinometers and surface benchmarks showed that landslides control was effective only when the proper stabilization measures were taken.INTRODUCTIONLandslides represent a major threat to human life, property, infrastructure and natural environment in most regions of the world. They are recognized by the scientific and politic authorities as having a major socio-economic impact and they represent a significant hazard for the population and the properties in particular locations. Landslide hazard expressed as the probability of occurrence within a reference time period and is a function of the spatial and temporal probability (Varnes, 1984; Guzzetti et al. 1999; Lee and Jones, 2004). The spatial probability of landslide initiation (susceptibility) is mainly related to static causal factors (slope inclination, material properties, etc.), while temporal probability is mainly related to dynamic causal factors such as rain input, increased groundwater levels and drainage, earthquakes, etc. (Van Westen et al. 2005)."

Jan 1, 2015

By Melanie Grob

Two commonly estimated fractal dimensions, called b and D values, represent statistical characteristics in the distribution of magnitude sizes (b) and spatial hypocenter locations (D) of microseismic events, respectively. We postulate that the values of b and D are related to specific stress regimes. Through different case studies of fluid injection into an oil/gas reservoir or geothermal field, we infer that the measured temporal variation in fractal dimension b is most likely due to significant changes in the local stress regime. The fracture dimension D indicates the spatial clustering of events. The distribution of these events can vary with time because of stress perturbations that (re)activate fractures whose direction favours their movement under a specific stress regime. Thus a combined statistical study of these two dimensions can help infer the variations of local stresses in a reservoir.

Jun 1, 2012

"In conjunction with Banick Mercur , Wright Engineers Limited designed the first multi-stage aqueous pressure oxidation system in an alkaline environment in North America. A three-stage slurry heating and slurry pressure let-down with heat recovery was an innovative approach to the problem of high energy cost with the low sulphur content of the ore. The design of this system required solving a number of problems associated with heating and pumping of slurries at pressures up to 3230 kPa and temperatures in excess of 220°C. Wright received an Award of Merit in October 1989, from the Canadian Consulting Engineering Awards Committee in the Process Category for its design of the Mercur pressure oxidation system.The Mercur Mine is located at the south end of the Oquirrh Mountains in Tooele County about 65 miles by road from Salt Lake City, Utah, U.S.A. The original mill was designed to process 5000 tpd of oxidized gold ore in a carbon-in-leach (CIL) circuit. A new ore treatment system was required to treat the substantial quantities of refractory ore reserves which could not be treated economically in the existing mill. The new pressure oxidation circuit makes the refractory ore amenable to gold recovery by oxidation of the sulphides contained in the ore .Wright Engineers Limited was commissioned by Barrick Mercur Gold Mine Ltd ., a wholly-owned subsidiary of American Barrick Resources, to design the pressure oxidation facility. This followed completion of a feasibility study by Wright which showed that the project was technically and economically viable.Work on the feasibility study began in 1986, detail design commenced in February 1987, and was completed in December 1987. Mechanical installation was completed in January 1988, and slurry feed began in February 1988. The plant has operated since June 1988 without major interruption . Wright was responsible for engineering, procurement and construction management for the addition of the 750 tpd pressure oxidation circuit to the existing mill and also had commissioning responsibility.Major unit processes involved in the pressure oxidation facility are ore thickening, three-stage slurry preheating, pressure oxidation and three-stage slurry cooling with heat recovery, stearn generation, propane and oxygen storage and a video graphic display process control system were included in the scope as process anciliaries.The pressure oxidation increases gold recovery from the refractory ore by conventional CIL from as low as 35% to more than 86070. A patent has been granted for the process."

Jan 1, 1989

By F. H. Samuel, J. E. Gruzleski, S. Valtierra, H. W. Doty, N. Andrade

In this work, the age-hardening behavior of cast Al-Si base alloys was investigated. It was found that multiple aging peaks are present in the age-hardening curves of Al-Si-Cu-Mg alloys. TEM observations reveal that the age-hardening behavior is related to the precipitation sequence of the alloy. For the Al-Si-Cu-Mg alloy, the first aging peak is the result from the high-density GP zones, while the subsequent are from metastable phases. The transition from GP zones to metastable phases may be the main reason of the formation of multiple aging peaks.

Jan 1, 2006

By Silvio E. Kruger

Real time measurement of wear and corrosion provides crucial information needed to determine an optimal schedule for corrective maintenance and is a powerful tool to maximise equipment availability and reliability. It also leads to savings from optimized spare parts handling and helps to avoid costs of accidents and their negative impact on safety and the environment. This paper presents the technology of ?painted-on? ultrasonic transducers that can be integrated to structures and accurately measure the remaining thickness and therefore determine wear or corrosion losses. These transducers have a small footprint, a performance comparable to other commercially available ultrasonic transducers and can sustain temperatures as high as 400ºC. The application of this technology to mining equipments and its potential benefits are discussed.

Aug 1, 2013

By E. Demedde

Carbon anodes in aluminium reduction cells are continuously consumed during electrolysis. In prebake cells the anodes are replaced at regular intervals. The spent anodes, called butts, are often allowed to cool in air while emitting fluorides into the building from the hot alumina cover and the adhering bath. In modem smelters spent anodes are placed inside enclosures and fluoride emissions during cooling are effectively reduced. Fluoride emissions from spent anodes were estimated by considering the kinetics of fluoride formation, a heat transfer analysis of the cooling anode butt and the ventilation flow from a cavity. Fluoride emissions from large anode butts cooling inside enclosures were compared with those cooling in air. Good agreement with published experimental values was obtained for enclosures having different leakage opemngs, when a hydrofluorination reaction of the spent anodes was included.

Jan 1, 2006

By A. Dunnett, N. J. Turner, J. Koyanagi, M. Ji

The analysis of rare earth element (REE) samples is a necessary part of the metallurgical process for rare-earth bearing ores, providing invaluable information during testing procedures. This requires a fast, multi-element technique, capable of analyzing a variety of matrices for all rare earth elements. X-ray Fluorescence spectrometry and Instrumental Neutron Activation Analysis are typically used for high concentrations of REE, but they have limitations for some process work applications due to an inability to measure all elements, longer analysis times, significant interferences and elevated detection levels. The work reported here uses new approaches with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) in order to achieve high precision and accuracy within acceptable timeframes. A combination of aerosol dilution and Kinetic Energy Discrimination (KED) produce a process solution assay method that is robust enough to deal with changing sample matrices and concentrations, whilst maintaining low reporting limits and precisions of less than 5% Relative Standard Deviation (RSD). For high concentration metallurgical and geological samples, a sodium peroxide fusion digestion procedure was used, followed by ICP-MS analysis using extended dynamic range (EDR) and KED. Using these technologies, it has been demonstrated that the necessary support can be given to metallurgical process work for REE extraction.

Jan 1, 2014

By Y. Chino

Cross-rolling, in which the roll axis is tilted by 7.5 degrees against the transverse direction, was carried out on a commercial magnesium alloy. The (0002) texture intensity of the cross-rolled specimen was lower than that of the unidirectionally rolled specimen. Also, the grain size of the cross-rolled specimen was smaller than that of the unidirectionally rolled specimen. As a result of the Erichsen tests at 433 ? 493 K, the press formability of the cross-rolled specimen was higher than that of the unidirectionally rolled specimen. The high formability of the cross-rolled specimen is attributed to both the reduction in (0002) texture intensity and the enhancement of grain refinement by the cross-rolling.

Jan 1, 2006

By J. Salazar

This paper presents a dynamic simulator of the semi-autogenous grinding operation deduced from first principles (non-stationary population balances) coupled to a Model-Based Real-Time Optimization (MBRTO) system to study optimizing strategies for an industrial semi-autogenous mill using genetic algorithms. For the design of the MBRTO both a validated first-principle steady-state model adapted on-line and a dynamic model were used to study the transient effect. The objective function considered is to maximize the ore throughput or the fine-product rate by changing the power-draw. For these purposes, these two performance indexes were introduced as fitness functions in the genetic algorithms. The three decision variables used were the ore feed rate, the water feed rate and the mill rotating velocity. The optimization problem was solved using a classical genetic algorithm with constant population. Constraints in the power draw and the filling level were handled by assigning a penalty function to the fitness function. Simulation results using industrial data for a large 1800 t/h copper-ore mill show the effectiveness of the system in finding the optimum controller set-points as a function of the process-operating constraints; mainly maximum ore feed rate, power draw and filling level. Starting from non- optimum conditions, the optimizer is able to improve the global performance index by 50% relative to a base case.

Jan 1, 2007

By J. Hoover

"IntroductionThis chapter will discuss the operational and maintenance aspects of a heavy media cyclone circuits as applied to coal processing and using magnetite as the media. It deals with heavy media bath separators in terms of types of media, equipment, circuits, media recovery, maintenance, and product handling. It will detail heavy media cyclone operation and supplement the previously described topics.The heavy media cyclone was first developed in the Netherlands by the Dutch State Mines in 1945. A cyclone plant was not built in North America until 1961. Traditionally, heavy media cyclones have been used to treat size fractions between 1lz in. (12 .6 mm) and 35 mesh (0.5 mm). High maintenance related to heavy media bath separators has recently prompted some plants to crush all raw coal to minus 2 in. for treatment in heavy media cyclones.The heavy media bath separators utilize only the force of gravity to make the separation between heavy and light particles. This requires lengthy retention time which can lower capacity and also is inefficient for finer particles. A heavy media cyclone utilizes centrifugal forces which are 20 to 200 times greater than the force of gravity. This means the separation between coal and the impurities occurs very quickly, therefore a low retention time is required allowing cyclones to have high tonnage capacities. Also these greater forces allow better separation for the finer particle sizes.Heavy media cyclones are now widely used to produce both metallurgical and thermal coal. Work is in progress to reduce magnetite consumption, extend wear life, increase tonnage capacity, improve separation efficiency and automatically control these cyclone circuits."

Jan 1, 1989

By A. A. Sirkeci, M. Tarkan, N. Acarkan, O. Kangal, G. Bulut

This investigation deals with the evaluation of the tailings of the Kirka Borax Plants. In this respect boron in the tailings was recovered and the utilization of the clayish fraction was investigated. There are five tailings ponds in Kirka four of which are used for the tailings of the borax concentrator and the remaining one is used for the tailings of the sodium penta-borax plant. Experiments were conducted with samples taken from ponds containing coarse fraction and fine fraction. Coarse fraction of Borax Concentrator were screened through a set of sieves. The fraction above 1 mm was removed with 41.5% recovery and 33.3% B203 content. Scrubbing was applied above 0.1 mm and products containing 32 to 34% B203 were obtained with recoveries around 35%. The tailings of sodium penta borax plant was also screened and it was found that 15% of boron reported to +1 mm size fraction with 35% B203 content. Sample containing fine tailings was treated by cycloning. The cyclone overflow was found to be below 6µm and it was separated to be used in the subsequent tests. The usage of cyclone overflow in paper, ceramics, glass, pigment and drilling industries was investigated. Since this fraction is mainly composed of carbonate minerals rather than clay minerals it was suggested that it may be used for construction and moulding purposes. Furthermore, the B203 content of the cyclone overflow was reduced to 2.4%.

Jan 1, 2004