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By Saravarim A.

"The aim in flotation systems is to control the grade and recovery of the product., numerical method or sampling and analysis is used to achieve this goal. Weakness of measuring instruments, lack of process knowledge, deficiencies in management and data processing in the control of flotation cells, has led the academic and industrial units to use numerical models. In this regard, using the results obtained from the experimental design carried out in the DTP line of Gol Gohar industrial and mining complex, a regression model was developed based on the analysis of variance. To present this model, after variance analysis of factors and interactions, all models were investigated and the final model was created based on 75% of the data. The model was tested with the remaining 25% of the data to confirm the goodness of the fit. The coefficient of determination for training and testing resulted 71% and 74%. Moreover, a feed forward back propagation neural network with different layers and neuron was used to model the results. The best network structure was 6-27-1 and the coefficient of determination for this network was 99% and 98% for training and test respectively. Given the complexity of neural network models and the relatively low accuracy of the regression model, neural network has a priority assuming we have access to a specialist. In addition, the results obtained from neural network can be used as expert systems to control and optimize the flotation cells.INTRODUCTIONThe primary objective of the flotation cell control is to maintain the product's (in this case tailing) recovery and grade, which represents the index for process efficiency and product quality. Continuous estimation of these indexes requires a significant amount of maintenance, and calibration of the continuous analyzers, in order to maintain an acceptable level of accuracy. Weakness of measurement equipment, lack of process knowledge and the general deficiency in management and processing of data in the flotation cell control, will lead industrial units to use smart methods such as mathematical models, regression and neural networks in near future (Panahi, Abdollahzadeh, & Sam, 2010). Artificial neural networks are inspired by the very complex structure of human brain in which millions of nerve cells solve problems or store information by communicating with each other. The duty of neural networks learning. It should be noted that learning in artificial neural networks is limited, and what is practically considered is the computing power of the network. A neural network consists of units called neurons, and has the capacity to handle a set of input data to produce a desired output data set. Each of these input and output data sets can be assumed as a vector (Soltanmohammadi & Noparast, 2006)."

Jan 1, 2016

By Alexandre Magno Alves de Oliveira

Os resíduos provenientes das indústrias cerâmicas demandam locais apropriados de descarte, gerando gastos, desperdício de matérias-primas e, quando o local de descarte é impróprio, problemas ambientais. Sendo assim, se faz necessário o estudo da reutilização destes resíduos, tanto para fins econômicos quanto ambientais. Dessa forma, a reutilização de chamote, resíduo oriundo do descarte de materiais cerâmicos, é possível através da sua incorporação em massas cerâmicas para a produção de novos materiais (blocos, tijolos, telhas, etc). O presente trabalho teve como objetivo analisar a influência do chamote em massas cerâmicas, comparando dosagens com substituição de 10%, 20% e 30% em massa com um traço de referência. Para isso foram realizados ensaios, com os quais pode-se obter as propriedades relacionadas a retração por secagem e por queima, absorção de água, perda ao fogo, porosidade aparente e tensão de ruptura à flexão. Em suma, pode-se concluir que o uso do chamote permite a obtenção de materiais com boa resistência mecânica, moderada absorção de água e com boas propriedades dimensionais, demonstrando ser uma alternativa ambientalmente amigável e economicamente viável.

Oct 30, 2017

By T O Aspinall

The Australian mineral industry involves a diverse range of expertise and skills. Within that, the mining industry, representing mine planning, mine management and equipment operation, has capital intensive, high productivity equipment and a small but skilled workforce. Continuing education for all personnel in the workforce after formal school courses will be an important contribution towards improving competitiveness. The non-tertiary sector represents a significant proportion of the workforce and requires as much attention as the tertiary educated group. Competency Based Training is now being developed for the mining industry in Australia under the National Training Board and the mining industry is well represented in establishing standards and curriculum. TAFE is a major source of accredited courses but some mining companies are also developing internal courses not necessarily for external accreditation. Articulation of such accredited courses to tertiary mining engineering courses has been considered. The education and training of equipment operators through continuing education requires attention to operating skills, an understanding of the productivity factors under the direct influence of the operator and providing product quality to the customer. The education and training of mining engineers has been widely covered and continuing close involvement of the mining industry is required to ensure well balanced courses in technical and interpersonal skills as well as motivation to continue learning for life. Postgraduate research is a part of continuing education but the mining industry has to continually address the adequate recognition of post-graduate qualifications for the increased technical or management expertise and the development of better analytical and problem solving skills which can be directed towards improving competitiveness. More attention has to be paid to providing adequate financial incentives to attract suitable students, particularly after attaining some experience, and to address their professional career path with a company so they are not significantly disadvantaged by undertaking post-graduate studies. The Chartered Professional Engineer status as provided by The Institution of Engineers, Australia to qualified candidates is being considered by The Australasian Institute of Mining and Metallurgy as a further recognition of a member's specific expertise and competence in mining and metallurgical engineering. Continuing education plays a major part in the maintenance of the expertise and competence required for a professional engineer to develop and also to retain chartered status. Continuing education will be a significant part of the education and training of all the mining workforce towards improving the competitiveness of the mining industry. The major challenges will be the motivation of all towards lifelong learning and the integration of the various programs towards providing the opportunity for a steady and satisfying career progression.

Jan 1, 1994

The integration of mining and mineral processing technologies into new advanced mining systems is considered to offer several benefits, including selective mining, reduction in waste, increased productivity, flexibility, and improved resource utilization. This paper focuses on underground hardrock mining and the integration of pre-concentration technologies into future mining systems as representing realistic, shorter-term integration options. Control of fragmentation to optimize grinding, pre-concentration of ores, in situ leaching, and modular mining/mineral processing systems are possible with existing technology. Current research is directed toward development of integrated underground systems that minimize surface activity and minimize or eliminate surface waste disposal. Results from a simulation model of an integrated underground pre-concentration system are presented.

Jan 1, 2002

By R. F. Yap, N. Arbiter, C. C. Harris

A fully-instrumented driving mechanism has been constructed to study the power, aerating and solid suspension characteristics of several laboratory flotation machines. Machines operating over normal flotation speed ranges give substantially constant power numbers in liquid systems indicating that they operate close to fully baffled turbulent flow conditions. Owing to lack of geometrical scaling, power numbers for different sizes of cells of the same make are different. Even larger differences occur between cells of different manufacturers. For a given impeller, varying the tank size did not significantly affect the power consumption. Tank geometry and baffling has a slight effect on power consumption with shrouded impellers. For a given impeller speed, suspension height decreases while power increases with increasing mass of solids in suspension. While power consumption is hardly affected by particle size and clearance between the impeller and tank bottom, the suspension height significantly increases as clearance increases and as particle size decreases. Aeration was found to affect not only power but also the suspension characteristics of the machine. For closely sized particles, drastic sedimentation occurred when a critical value of the air flow number was exceeded. The critical air flow number decreased with increasing particle size. This effect was less marked with a wide particle size range. The self-aerating capacity of flotation machines increases with cell size at a given speed for the same impeller-shroud system, but decreases in the presence of frother and solids. Equations have been established for correlating all of the studied variables. Data taken from the literature were also correlated with these equations. The modern mechanical flotation machine has, over a period of 60 years, displaced other designs to become the dominant type. Once the correct chemical environmental conditions have been established, the major requirement, selective mineral-air adherence, is essentially a function of two operating variables — impeller speed and air rate. The special nature of this dependence is such that in the same apparatus, but under different operating conditions, adherence can be either prevented or destroyed. Another aspect of this observation is that flotation machines though differing in detail to a considerable extent can produce similar metallurgical results. It must be concluded that having determined the correct reagent levels, establishing the correct operating conditions are at least as important as machine design. Since about 1960, after 30 years of fairly stable circumstances, manufacturers have been developing new types of machines whose major feature is emphasis on pulp flow characteristics by virtue of new im-peller-stator designs. As far as can be ascertained, these new designs necessitate radical departures from accepted impeller speed-air rate values. Performance data are still awaited. Flotation machine development has been empirical, as is selection of operating conditions. The purpose of the work at Columbia University has been to elucidate the fundamentals of the subject so that the purely mechanical aspects of the flotation process can be understood in hydrodynamic terms.1-6 Hopefully, this might lead to intelligent selection of a particular machine and its operating conditions for a specific ore based on a minimum of testing, or even to new types of flotation machines. The present investigation is the most comprehensive to date.7,8 Earlier work, which was largely exploratory, has been repeated and extended and employes the most accurate measuring techniques available. Additionally, sufficient hydrodynamic data were obtained under flotation conditions to delineate the relevant operating ranges. Attention has been given to scaling in that several geometrically scaled tanks and impellers have been constructed and tested; it has been pointed out elsewhere that undistorted geometrical scaling rarely pertains in flotation machine design.5 This paper is divided into sections dealing with relevant combinations of the three phases: liquid, air and solid. Summaries of the literature have been given in previous publications2-4 and will not be repeated here. Recently, several reviews of mixing have appeared, which can be usefully referenced.9-11 It is of interest to note that flotation is not included

Jan 1, 1970

By C. M. Young

The safety lamp is the most common and convenient apparatus for detecting inflammable gases in mines, the presence of gas being shown by a blue flame, called the cap, if the wick has been lowered to suppress the luminous flame. The height of the cap increases with the proportion of gas and with the temperature of the lamp flame. Lamps of the Wolf type, the fuel of which is benzine, have a hotter flame than lamps in which vegetable oils are used, such as the Davy, and the Clanny, and are more sensitive than the latter and their many modifications. The Piehler alcohol lamp gives a still higher cap while the Clowes hydrogen lamp is most sensitive of all. While the effect of the temperature of the source of ignition is well known, the writer knows of no previous attempt to correlate the change of this temperature with change of the height of the cap produced, In order to determine the height of the cap at various temperatures, it was necessary to have a source of ignition the temperature of which could be accurately controlled over a considerable range. This condition was met by a coil of wire of high fusing point heated by an electric current controlled by a variable resistance. The use of a coil offered the further advantage of freedom from complications due to the flame of a burning fuel. Such a flame, being itself of variable height, would to some extent raise or lower the elevation of the base of the cap and therefore add to the difficulty of determining the height of the cap. Besides this, the presence of a small cap from the lamp fuel, commonly known as the "fuel cap," would interfere with the observation of small gas caps. After some experiment, a coil was made of platinum wire, No. 26, diameter 0.016 in. The coil was 17/64 in. (6.746 mm.) in outside diameter and had eight full turns in a length of 1/2 in. (12.69 mm.). This was connected to an electric circuit through an adjustable resistance, as shown in Fig. 1. In order to measure the temperature, a thermocouple was inserted in the center of the coil; the leads passed out at the ends and were ccnducted to a millivoltmeter. It is probable that the current of air passing upward through the coil resulted in the indication of a tempera-

Jan 1, 1920

By Friedel. Michael J.

The U.S. Bureau of Mines investigated acoustic emission (AE) and the Kaiser effect in six types of rock: St. Cloud gray granodiorite, Barre granite, Dresser basalt, Salem limestone, Berea sandstone, and a volcanic tuff. AE signatures were used for interpreting the rock deformation stage and for indicating mechanisms of failure in uniaxial compression. The research demonstrated the advantages of using the volumetric stress-strain curve, as opposed to the more conventional uniaxial curve, for correlating AE response signatures with deformation stages and fracture processes in the rock. Standardized experimental procedures were used for the AE monitoring. The Kaiser effect was shown to be capable of determining prestress levels to within a few percentage points in uniaxial compression tests. Also, prestress memory was shown to be retained in the rock for periods of up to at least. 5 months, the maximum period of testing. The Kaiser effect AE technology holds promise for providing a comparatively inexpensive and less complex method for examihing stress history in rock. However, since the conftning stress has a pronounced influence on the Kaiser effect, it must be considered in developing technology for determining peak fteld stresses based on the Kaiser effect.

Jan 1, 1990

By G. G. Xiong

Water-sealed cyclone is a new efficient equipment to use for grading,concentrating of slurry, it was researched and developed by the Kunming Metallurgy Research Institute in the 1980s , and ac-cessed to the 1990 national invention award and the national patent products (ZL02245313.X ). The equipment and technology are innovative, firstly, we design a set of micro-pressure (0.005~0.008MPa) water-sealed device, which eliminates the gas phase of three-phase of sol-id-liquid-gas of the traditional general hydrocyclone grading process, it only has solid and liquid phases. Secondly, the axial velocity envelope surface which is a factor of controlling the accuracy of grading changes to a wedge rotation; and the interface of upward flow to down flow changes from surface to the solid, it can improve grading accuracy. Thirdly, water-sealed box and catheter devices make the stilling which pass through the cyclone cone centrifugal force fields re-enter the pressure grading zone of catheter. The three innovations make water-sealed cyclone can reduce the loss of overflow and has less mud in stilling product. Because the excellent performance, the water-sealed cyclone has application in non-ferrous metals, ferrous metals, non-metallic and aluminum hydroxide industries for grading, desliming and concentrating since it has successfully developed.

Jan 1, 2014

By Foster Fraas

The objective of this research was separation of one highly conductive mineral from a second conductive mineral , a procedure which is impractical in commercial electrostatic separators using metal rolls . Such separators permit separation of nonconductive from conductive minerals . A new technique involved use of carrier electrode rolls specially prepared by anodizing and / or oxidizing at high temperatures to form suitable oxide surfaces . Specific oxides included aluminum , copper , and nickel . The significant result provided by the new surfaces was the extension of the separation range to higher conductivities , an extension in relative mineral conductivity from 10-14 mhos . The results are in accordance with the blocking- layer theory .

Jan 1, 1964

By A. Warczok, C. M. Diaz, A. Bergman, T. Utigard, M. Barati

The world wide consumption of energy is steadily increasing and by 2030 it is forecasted to grow by another 50%, leading to mounting political and economic pressures. For any pyrometallurgical operation, it is therefore paramount to investigate and implement methods to decrease the use of energy. In the pyrometallurgical processing of steel, copper, nickel and other high temperature metals, a large amount of energy is lost in hot off-gases, molten slags, mattes and molten metals. Most of this energy is generally lost during the cooling and solidification steps with very little focus on energy recovery or reuse. In this paper we will quantify how much energy is contained in the various slag streams, then review previous attempts and methods employed to recover some of this energy, and finally evaluate some novel technologies that could potentially be employed.

Jan 1, 2011

By g. Caproni

The main constituent of the feed to the "Sulphide Section" (31 t/h), in the F. Sartori Plant (6000 tid) of the Miniere di Mon)eponi(Sardinia), is the ore of the Campo Pisano -Funtanaperda Mine (1 ? Difficulties have always been experienced in the treatment of this ore, owing to the extramely fine Pyrite-Sphalerite intergrowth and to the high Pyrite and soluble salts contents. The first mentioned difficulty was overcome with a rather complex flowsheet (see fig.1A and lB)(2); the others with a reagent combination that required a pH of 11 in a pulp loaded with soluble salts. This meant high consumption of alkalizer, and also of the other reagents; furthermore the alkalizer had to be mainly NaOH with only minor amounts of lime, because the latter tended to depress not only the pyrite but also the middlings, which were supposed to float. With dialchylditiophosphate alone as a collector, a lower pH could have been used, but a certain amount of amylxanthate was indispensable to promote flotation of the middlings. On the other hand, a bulk-flotation of sphalerite and pyrite at low pH could not be very advantageous on account of the high pyrite content in the feed(3).

Jan 1, 1971

By Michael J. Beus

The National Institute of Occupational Safety and Health-Spokane Research Laboratory (NIOSH-SRL) have developed a Shaft Conveyance Monitoring System (SCMS). Assessment of current hoisting technology has shown that monitoring wire rope tension and conveyance position and load directly from the skip or cage top offers several significant safety, production, and maintenance advantages. The SCMS consists of conveyance position and guide displacement sensors, a battery power supply and charging system, and a new sensor to measure hoist rope tension. This device provides a warning of the occurrence of ?slack rope? a particularly dangerous condition. A 2.4 GHz radio link transmits data to the hoistroom. A reduced scale hoisting test facility has been constructed to test these components prior to field trials. The advantages of monitoring wire rope tension and conveyance position and load directly from a skip or cage top will be discussed. Field tests are underway in full-size shafts to refine the concept and evaluate long-term reliability and maintenance requirements. Application of this technology may result in decreased maintenance costs as well as safer, more productive hoisting operations.

May 1, 2001

By T. H. Etsell, P. Kerr, Qi Liu

"The objective of this investigation was to study the reaction mechanisms during the reduction of iron oxides in the presence of calcium chloride and carbon black as a simplified iron segregation process. The gas phase was analyzed by mass spectroscopy and the solid reaction products were analyzed by scanning electron microscopy. Mass spectroscopy, combined with thermogravimetric analysis and differential scanning calorimetry, revealed the presence of several gases at elevated temperatures over time, and the scanning electron microscope in combination with energy dispersive X-ray analysis illustrated the growth of a metallic iron phase on or near the carbon substrate. The results correlated well with similar copper and nickel segregation processes, but also introduced new insights that challenge the simplicity of the current models. The formation and transport of gaseous iron species to the carbon substrate in the presence of steam and hydrogen were evident during the reduction process that was studied; however, there is more happening at a mineralogical level, based on evidence of a liquid phase resulting in substantial growth due to an apparent fluxing effect created by the calcium chloride.These results help to better explain the chemical reactions and, in turn, the thermodynamics and kinetics of iron segregation processes related to the beneficiation of low grade complex iron ores. The results are also applicable to the production of metallic iron and concentrated titanium dioxide from ilmenite ores. The benefit of this process is that it allows ores in which the iron minerals are intimately associated with gangue minerals to be processed in circumstances where conventional mineral processing techniques are unsuitable or incapable of upgrading the material."

Jan 1, 2016

By Mohan Dutt

This paper is concerned with applied platinum resistance thermometry which involves many considerations absent in precision thermometry. The historical development of the Callendar-Van Dusen Equation which describes the resistance- temperature relation of pure platinum is discussed. The advantage of using platinum resistance temperature sensors over thermocouples is described, and the improvements in design and construction of these sensors that have come about in the past few years are discussed. Integral and remote bridges that convert resistance changes into voltage together with signal conditioning techniques and equipment for voltage or current signals are described. Errors encountered in temperature measuring schemes and methods to reduce these errors are summarized.

Jan 1, 1969

By C. N. Adams

The purpose of this investigation was to evaluate the physical and mechanical properties of high-purity titanium made by two processes. Sodium-reduced metal with 58 Brinell hardness number (B.h.n.) and electrorefined metal with 60 B.h.n. and 70 B.h.n. were used. Titanium of these hardness levels did not work-harden excessively, and beyond 40 percent cold work the hardening effect was not great. Rapid softening occurred when the metal was annealed at temperature between 300° and 600° C. Full annealing, as determined by property and microstructure studies, was accomplished after 30 minutes at 700° C. A recrystallization diagram is presented which is based on determinations of annealed grain size as a function of rolling reduction and annealing time. For reductions of less than 20 percent, exaggerated grain growth occurred during annealing; for reductions greater than 20 percent, the variation in grain size for each annealing temperature was minor.

Jan 1, 1961

By Flávio Parreiras Marques

A microabrasão é uma técnica para produzir desgaste abrasivo em escala micrométrica. Neste trabalho estudamos uma liga fundida de cobalto com composição química próxima à da superliga comercial Stellite 6com composição eutética sendo a matriz constituída por uma solução sólida de cobalto, cromo e molibdênio que embebe uma grande quantidade carbonetos eutéticos de cromo. O objetivo deste estudo é avaliar a resistência ao desgaste bem como os micromecanismos dominantes através de ensaios de microabrasão. Foram usados três diferentes tipos de lama abrasiva, sílica, alumina e carbeto de silício com uma concentração de 0,1 g/cm3, carga de 0,3 N e uma distância deslizada de 48 metros. O menor coeficiente de desgaste foi obtido com sílica e o maior com carbeto de silício. O micromecanismo dominante foi o riscamento com riscos em toda superfície da amostra e presença de indentações apenas na matriz.

Aug 16, 2017

By Daniel B. Brimhall

The research presented here was initiated to investigate the role of atmospheric oxygen in the leaching of copper waste dumps. The problem of increasing the recovery rate of copper from these dumps is or great importance considering there are by conservative estimate in excess of fifteen billion pounds of copper located in dumps in the western United States. At this time, there is an increased interest in recovering copper from these dumps on a large scale. Large tonnages of low-grade material are being placed on the waste dumps of most copper mining operations in the western United States each day. The size of these dumps ranges from 5.5 million tons at Mineral Park, Arizona, to 4 billion tons at Kennecott's Utah operation (1). Leach solutions are recycled and contain ferrous and ferric sulfates. Large quantities of dissolved aluminum, magnesium and calcium salts may also be present. To this solution make up water is added to maintain the solution inventory and sulfuric acid is added for pH adjustment. Iron is introduced into the leach solution by the dissolution of the iron-containing sulfide and oxidized minerals present in the ore deposit. In addition to the iron from dump leaching, iron is also introduced during the precipitation process when the pregnant solution is passed over metallic scrap iron if cementation is used to reduce the copper in solution.

Jan 1, 1972

By John V. Beall

The mining industry of Japan is not very large, but it is very old. Some of the mines have 1000 years of history. At Nara, the capitol 1300 years ago, the great Buddha of bronze that was cast at that time was of metal mined from several localities in Japan including the Akenobe-Ikuno district, one of the present Mitsubishi properties. Methods of smelting copper and iron, it is believed, came from China via Korea. A characteristic of the Japanese mining industry today is one of buying abroad and treating at home, a variety of ores of different compositions. All in all, Japan's mineral deposits under its own flag are inadequate for its great industrial strengths.

Jan 5, 1969

By Robert S. Williams

On several occasions, when 60-40 brass is first obtained in the beta condition by quenching at about 825" C. and is then reheated, the writers have noticed that reerystallization will take place in the form of twin crystals at the grain boundaries of the original beta crystals. It was, therefore, thought that interesting results would be obtained if this twinning process was studied further, especially as to the temperature at which it first occurs. The material used in the investigation was a bar of extruded muntz metal, 1/2 in. in diameter, and of the following composition: Copper, 60.21 per cent.; zinc, 39.73 per cent.; lead, trace; iron, trace; tin, nil. Specimens 1 in. in length were sawed from this bar and a hole was drilled into the side of each specimen until it reached the center, and the tip of a platinum-platinum rhodium thermocouple was inserted. A small Hoskins' resistance-type electric furnace was used for heating the specimens. The specimens were first heated at 840' C. for 2 hr. and then quenched ' in cold water, in order to get the material entirely in the beta state. In every case, in the reheating process, the furnace was brought to the desired temperature before the specimen was introduced. The time occupied in preheating was from 20 to 30 min. By sawing back 1/4 in. on each side of the hole, two parts were obtained from each specimen and duplicate observations were possible. The specimens were held at the reheating temperatures for periods of 15 min., 30 min., 1, 2, and 4 hr. All specimens were etched with a freshly prepared mixture of equal volumes of concentrated NH4IOH and H2O2.

Jan 1, 1924

By Atta Ur Rehman, Kwame Awuah‑Offei

This paper evaluates the effectiveness of similitude theory in predicting the draft of a rubber tire loader’s bucket during initial penetration. The work uses 1:16 and 1:8 scale models of an 18-t capacity load haul dump, scaled with the Buckingham Pi Theorem, to evaluate the prediction of draft and penetration under different operating and different dynamic conditions. The authors hypothesize that the observed relationships between draft and longitudinal penetration and the operating and dynamic conditions will hold true for an upscaled model. Similarly, the authors hypothesized that the results of experiments conducted with the smaller scaled model should predict the draft on an upscaled model. The results show that the relationships between draft and longitudinal penetration and operating and dynamic parameters are similar for both scaled models. Similarly, the draft on the upscaled model, predicted by using the experimental results of the small model, is similar to the measured draft on the upscaled model. The mean difference between the two is 1.71 N with 95% confidence interval of [-3.51, 6.93], which is very good given the average draft is approximately 330 N. Thus, the work indicates that both hypotheses are true for draft. However, the work shows that scaling muck pile particle sizes using the Buckingham Pi Theorem is not adequate to ensure good predictions of penetration. This work provides insights that will help design engineers to acquire useful data on scaled models and use it for various analyses on heavy machinery.

Oct 6, 2021