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By D. S. Salonine

Aluminum alloys are widely used in modern industry. Tubes and hollow shapes give great opportunities for structural purposes as well as fluid transport due to their stiffness and lightness, Extrusions on a mandrel or through a bridge die, that requires splitting of the billet with re-welding, produce hollow shapes with varied contours, fins and multiple cavities. Moving and stationary mandrels, mandrel lubrication, tooling for ribbed-tube heat exchangers, and for drilling pipes are considered. Bridge dies can be classified by the bridge position relative to the die face, by mandrel support structure, and by assembly type, The main parameters influencing the quality of the die-welded seams are considered, The difficulties of extruding various alloys through bridge dies are discussed in terms of metallurgical factors, Some approaches to the calculation of the stresses in a bridge are presented.

Jan 1, 2005

By P. Karimi, A. Amini, H. Abdollahi, A. Mirzaeian

Due to detrimental effects of cyanidation process on the environment in gold industry, application of cyanide alternatives such as thiourea are being highly considered in recent projects. In this study, the extraction of gold from poly metal ore, using thiourea was precisely investigated. The representative sample contained 2.5 ppm Au and 160 ppm Ag. The sample was categorized as oxide gold ore, because the main part of its pyrite was changed to iron oxide and hydroxide such as goethite and lepidocrosite. According to mineralogy, the main gangue mineral was quartz. It shows that gold grains are free and interlocked with quartz matrix. Also, the presence of a high amount of silver in free and sulfide forms and also the low content of other sulfide minerals such as base metal sulfides is a remarkable point of these studies. In the gold extraction process with thiourea, there are several parameters that affect the rate of gold dissolution such as concentrations of thiourea as a gold lixiviant and ferric sulfate as an oxidant, pH and size fraction of feed and leaching time. The influence of these parameters on the gold dissolution rate were investigated and optimized. The results showed that the concentration of thiourea is the most influential parameter which could increase the gold recovery to 71% (at 10 g/kg sample). The optimal amount of ferric sulfate was determined as 6 g/kg sample. Also, the optimal levels of size fraction of feed and pH of solution were 88% under 75 micron and 2 as acidity; respectively. Leaching time was 6 hrs. In addition, this sample was leached with cyanide and the optimized values of size fraction of d88=75 microns, pH=10.45, 2500 ppm of sodium cyanide with time leaching of 24 hours were concluded for maximum recovery of gold in solution. Finally, the results of cyanidation tests were compared to the thiourea dissolution after optimizing all affected parameters in cyanidation process.

Jan 1, 2016

By T. Gonzales, M. Maleki, M. Caçador, B. Climenhaga, H. Ghorbani

The campaign life of furnaces in the copper making industry is greatly affected by damage caused by normal operation cycling and abnormal conditions. Proper monitoring and assessment of the existing conditions and safe remaining life of the vessels and their refractory lining is key to prevent an unplanned early replacement. This paper presents an industry-proven refractory management program as well as a typical fitness-for-service assessment of a rotary vessel shell in order to extend the campaign life of copper making furnaces and enhance safety. The furnace refractory management system involves a comprehensive audit and monitoring program which has been successfully applied to several copper flash smelting furnaces over the past 15 years. The fitness for service assessment provides a methodology to estimate the remaining life of the steel components by evaluating the existing damage and future damage rate based on the historical survey data. The above practices can provide the operator with cost savings by extending the vessel campaign life in lieu of implementing more rigorous refractory lining and shell audits. INTRODUCTION Primary copper smelting is generally divided into two categories of flash smelting and open bath smelting. There are many different types of vessels that can be used to convert the copper concentrate to blister copper including, flash, Mitsubishi process, TSL (ISA/Ausmelt), SKS Bottom Blowing, Anode and Teniente/Noranda furnaces, reactors, and Peirce Smith converters. Each vessel has its own complex and intense environment which requires careful refractory and steel design to withstand the severe thermomechanical and thermochemical attacks within its campaign life. The campaign life of furnaces is greatly affected by damage caused by normal operation cycling and abnormal conditions. Proper assessment of the existing conditions and safe remaining life of the vessels and/or refractory lining is key to prevent an unplanned early replacement. This paper presents an industry-proven refractory management program as well as a fitness-for- service assessment methodology to estimate the remaining campaign life of copper making furnaces resulting in cost savings and enhanced safety of the operating vessels.

Jan 1, 2019

"High Pressure Grinding Roll (“HPGR”) technology is applied in a broadening range of minerals processing applications for relatively wet or moist materials. HPGR grinding of dry material or involving drying and air classification is more common, for example in cement manufacturing. A number of minerals processing plants are also operating with dry material, either due to process reasons, such as considerations of preceding or subsequent process stages, or as dictated by local conditions of arid areas and scarcity of water. The present world-wide expectation of decreasing availability of water supply urges us to look for alternatives that minimize water consumption.Recently established and envisaged future HPGR applications with dry ores have indicated that the technology of dry crushing and classification as practiced in cement and limestone grinding can be applied in minerals processing. Moreover, dry technology could very well be applied for generating a final fine product at sizes near or below 100 microns, as may be required for beneficiation by, for instance, flotation, magnetic separation or tank leaching.Dry HPGR grinding requires special attention in maintaining suitable process economics, when considering power input in grinding, drying and classification. In some cases, HPGR capacity and roll surface wear life may be negatively affected by a lack of moisture in the feed.This publication summarizes some of the features of, and experiences in dry HPGR applications. This includes design aspects of the classification system and discussion of the wear protection of the roll surfaces. The paper also includes examples of operational experiences of dry practices in minerals processing and cement plants."

Jan 1, 2012

By A. Alfantazi, L. Choudhary

Gold leaching in thiosulfate solution has attracted widespread research interest through the last two decades primarily due to its perceived environmental benefits in comparison to the conventional gold cyanidation technique. However, the data on the corrosion and/or corrosion-induced failures of plant infrastructure materials in the solutions relevant to thiosulfate gold leaching are very limited. Accordingly, this study aims to characterize the electrochemical corrosion behavior of stainless steel 316L in the thiosulfate gold leaching solutions. Electrochemical corrosion response was investigated using potentiodynamic polarization and electrochemical impedance spectroscopy. The morphology of corroded specimens was analyzed using scanning electron microscopy.

Jan 1, 2014

By J. A. Hillier

"IntroductionThe purpose of sampling is to remove a portion of material from a stream which is representative of it in size, moisture and mineral content.To prevent the effects of segregation, generally caused by the way in which a conveyor, pipe or launder is loaded or directed, the sampler should cut proportionally the entire cross section of the stream.If one conveyor transfers to another at a right angle, fines may be dropped on the near side, and the coarse material thrown to the opposite side. Segregation can also occur as a result of the motion of a conveyor belt passing over the idlers causing the coarse material to roll to the sides of the belt.When slurry changes direction of flow in a launder or pipe, the heavier and coarser fraction will centrifuge to the outside of the curve and tend to remain on one side of the stream. Similarly, if two streams joining in a common launder are not mixed at the point of confluence, they will continue down the launder unmixed . This effect is particularly noticeable in a plastic lined launder.Therefore, a proportional sample is usually accomplished by a constant rate of cutter travel across the entire stream, making certain that the cutter is not full or splashing over before reaching the end of travel.The cutter should operate on a constant interval based on time, tonnage and uniformity of flow. The opening should be at least three times the width of the largest piece to be sampled. The cutter width is more critical with ore samples where particle sizes are large. With slurry samples, the opening is usually much larger than the minimum in order to obtain sufficient samples"

Jan 1, 1989

By Rufus L. Chaney

A new technology is available to the Ni mining and remediation community to “phytomine” Ni from mineralized or contaminated soils using rare plants which hyperaccumulate Ni to over 1% of shoot dry matter. Research has identified useful plant species, and even bred improved cultivars of Alyssum murale and Alyssum corsicum for commercial phytomining in temperate regions. All agronomic practices (fertilization, soil amendments, planting and harvest methods) needed for economic phytomining were identified to attain high yields and high Ni concentration in the biomass. In tropical regions, other species are available such as Phyllanthus which accumulate over 1% Ni in dry shoots. These species are perennial so they regrow after annual cutting to harvest biomass. Expiration of our patents on the technology opens the opportunity for other organizations which control Ni rich natural soils or contaminated soils requiring remediation to commercialize the technologies. Inexpensive methods to remediate/revitalize Ni contaminated phytotoxic soils using agronomic approaches have also been developed and demonstrated at Port Colborne, Ontario, but adoption is delayed until formal agreements with government are completed. These new simple remediation and profitable phytomining technologies can obtain Ni from soils which contain Ni well below levels considered economic for current mining technologies, and the plants biopurify the Ni so it is easy to recover Ni metal from plant ash by pyrometallurgical or hydrometallurgical technologies. Although increasing pH decreases the solubility of Ni in all soils, raising pH increases Ni accumulation by Alyssum species. Hence usual chemical extraction methods for phytoavailable soil metals such as the DTPA- or NH4-OAc-extraction cannot predict Ni accumulation by Alyssum species.

Jan 1, 2016

By H. R. Manouchehri, A. Weh

"High voltage electric pulse comminution (SELFRAG) relies on inducing electrical breakdown that occurs when the resistivity of a dielectric is insufficient to completely block all transfer of electricity while the conductivity is not high enough to fully accommodate the flow of electricity without considerable changes to the crystal lattice. The technology is based on introducing the electrical discharges into solids immersed in water and placed between two electrodes. The technology has received significant attention since investigations have revealed the potential for fully fragmenting particles or pre-weakening rocks in order to reduce the energy consumption in comminution practices, improve liberation and potentially increase the recovery in mineral processing. Mineralogical analysis of samples showed possible liberation at coarser sizes by high voltage breakage in comparison with conventional mechanical comminution.This study explored the potential of implementing SELFRAG to treat the Sandvik’s Mittersill mine tungsten ore (scheelite) for recovery improvement. Accordingly, standard SELFRAG tests were conducted on four samples from the tungsten process plant to evaluate the energy-breakage relation and potential to liberate the value minerals at coarser size fraction for recovery improvement. The size reduction of the ore after processing with SELFRAG revealed that size deportment occurs at 0.4, 0.2, and 0.1 mm, which indicated potential liberation of gangue and target minerals at respective sizes. In comparison with conventional milling, the difference is the deportment of values into 0.4 mm sizes, which was, to some extent, confirmed by SEM liberation analysis. However, more tests are needed to proof the concept. The study has indicated that, despite consuming more energy in comparison with conventional mechanical comminution, there are promising prospects in liberating the values at coarser fraction and improve recovery by making use of SELFRAG. The energy consumption can be reduced through customized generator and equipment setup, which must be further investigated."

Jan 1, 2016

By C. Matthews, A. Vo

Australia is one of the world’s leading exporters of bulk commodities and the extensive use of sampling equipment is key to the successful management of each mining operation. At the process plant, without a full understanding of the feed, product and tails, it is impossible to fully optimise the performance of the plant, such that the metallurgical balance is often open to error. At the port, a statistically correct, bias free and compliant sampling system is crucial to ensuring exported minerals are reflective of their true value and to avoid penalties. Over the last decade, as a result of the iron ore boom, there has been high demand for reliable, representative and standard compliant solids sample systems in Australia. This paper reviews several solids sampling applications at Australian mine sites, the challenges and experience gained and how the implementation of reliable representative sampling systems has provided better understanding of plant process performance, improved plant control and overall benefits to the operations. INTRODUCTION Mining is the primary contributor to the Australian economy with Australia ranking in the top 4 in economic resources for 21 primary industrial minerals in 2016 (Britt, et al., 2017). Australia is one of the world leaders in the export of the majority of its commodities including gold, copper and iron ore (Britt, et al., 2017). Therefore, a suitable and standard compliant sampling system is essential for evaluating plant performance and content verification. At the mine and at the port, the larger iron ore miners in Australia have developed stockpile models to predict the grade of their ore down to individual blocks of the stockpile. This allows the miner to create the right blend of material for sale to their customers and ensures they are not underselling their product or at risk of penalties for impurities or low grade. As an example, the average difference between the benchmark 62% Fe and low grade 58% Fe fines at the time of this report averaged US $20/tonne according to the Metal Bulletin Iron Ore Index (Fastmarkets MB, 2019). At a shipload of 180kt this would be a variation of US $3.6M. Whilst this is an extreme example, it highlights the economic importance of producing the correct grade product and a recognised representative sample of said product.

Jan 1, 2019

By Waldbillig. D.

A baseline of the poisoning effect of hydrogen sulfide (H2S) fuel impurities on solid oxide fuel cell (SOFC) anodes was developed using polarization testing. After the baseline behaviour was characterized, tests to study the effect of various H2S concentrations on the rate and amount of cell voltage degradation and recovery were performed. Attempts were made to improve the rate and amount of recovery by various methods. Testing was very reproducible, but significant electrochemical performance degradation was seen after all H2S poisoning tests even at an H2S concentration of 0.1 ppm. Degradation is initially quite rapid, but after a period of time the rate of degradation levels off. After poisoning was complete, the H2S flow was stopped and the cells were allowed to recover. Some recovery was seen after poisoning, but cell performance was never fully recovered.

Jan 1, 2005

By S. Feinstein, I. Reznik, Y. H. Hatzor, O. Shitrit, Y. O. Rosenberg, H. J. Vinegar, S. Nguyen

"We report the effects of porosity and total organic carbon (TOC) content on the mechanical behavior of organic-rich chalks, based on laboratory measurements. The organic-rich chalks are from the Senonian Ghareb and Mishash formations. This deposit is an immature oil-prone source rock, about 300 meters thick, situated at shallow depths (several hundreds of meters) in the Shefela basin in central Israel. The study is based on core data collected from the Zoharim borehole.Three main phases comprise the bulk volume of this rock: 1) carbonate mineralogical phase (predominantly calcite); 2) pores (mostly saturated with brine); and 3) solid organic phase (type IIS kerogen). The mechanical effects of porosity (23-45%) and TOC (4-19%) are evaluated based on bulk incompressibilities vs. volumetric fractions analysis. Volumetric fractions of mineralogical and organic phases were obtained by porosity, density and TOC measurements. Saturated rock bulk moduli were measured through ultrasonic velocity measurements. Saturated rock bulk moduli correlate best with the sum of kerogen and pore volume fractions, rather than each of them separately. The volumetric fractions were also used to define the range of bulk modulus of the organic-rich chalk, using the Hashin-Shtrikman upper and lower bounds. Based on Marion's Bounding Average Method (BAM), the normalized stiffness factor of the chalk averaged at w=0.197, indicating a soft pore geometry. Using the average normalized stiffness factor, the BAM predictions showed excellent match with the saturated rock bulk modulus and the sum of kerogen and pore volume fractions. Based on our findings, it is inferred that kerogen grains do not support the solid skeleton but are distributed between the minerals grains. We also propose here a straightforward approach for calculating the Hashin-Shtrikman bounds, based on TOC and porosity measurements. The mechanical effects of porosity and TOC indicated here are very important for the understanding of the influence of immature kerogen presence in highly porous chalks, as the Ghareb and Mishash formations."

Jan 1, 2015

By James A. Deeks

"Motor failures and equipment bearing failures are responsible for reduced productivity.With the introduction of computers and data acquisition systems, users are now able to monitor, report and trend deteriorating conditions and take corrective action before a critical shutdown occurs.This paper discusses the monitoring and trend analysis of' motors, and motor and equipment bearings. With today's digital electronics technology users are now able to monitor their equipment, detect deteriorating or abnormal conditions quickly, alarm the condition locally and or remotely, and decide if immediate corrective action is necessary or if it can be delayed until the end of a work Shift. All of this can be done long before any damage is done to the equipment.Monitoring Trend AnalysisIt is no longer necessary to compromise in selecting products, since state-of-the-art designs allow the adjustment in such small increments that the users are able to detect minute changes in a system's performance.Monitoring and trending of motors and equipment bearings is now available in economical packages which can be expanded as a system grows. Simply select the information you need, set the parameters, choose the scan time, and decide on the degree of reporting.Buffer storage of short-term monitoring of a number of analogue channels permit the user to view the recent history of motor data such as: motor average load, unbalance, motor current, ground fault, reserve thermal capacity, plus all of the settings of the protective device.A decision can be made to freeze the stored information after the motor stops or after the motor starts. Then the user is able to recall the conditions and diagnose the performance and the cause of the abnormal condition. Typical scan times range from ¼ second to 5 seconds ."

Jan 1, 1992

By Xiaoxing Hu, Guibing Zheng, Yangge Zhu, Xingrong Zhang

"In China, more than 90 percent of titanium resources are reserved in vanadic titano-magnetite deposits. In this type of ore, the same elements such as Ti, Fe, Ca, Mg exist on surface of both ilmenite and titanaugite (the gangue mineral) because of isomorphism, which makes selective flotation difficult. Therefore, how to enlarge the floatability difference between these two minerals has always been a research emphasis and still needs to be studied further. In this paper, the pre-treatment methods using ultrasonic wave were proposed. The results indicate that ultrasonic treatment shows beneficial effect to enlarge the floatability difference, and the effect will be strengthened by extending the ultrasonic treatment time or increasing the ultrasonic power. The mechanism was investigated through infrared spectroscopic (FT-IR) analysis. Collector interacts with Ca and Mg which results in titanaugite flotation, after ultrasonic treatment, the dissolution of Ca and Mg is intensified, which leads to the lack of active points on mineral surface, so the floatability of titanaugite is depressed. Meanwhile, collector mainly interacts with Fe which results in ilmenite flotation, and the present of ultrasonic might promote its oxidation (Fe2+ to Fe3+), so the floatability of ilmenite after sonication is increased.INTRODUCTIONUltrasonic is the sound wave with frequency of 2 × 10-4 Hz~2 × 10-9Hz. Since the first International Symposium of Sonochemistry in 1986, the application of ultrasonic wave is more and more extensive. In researches about mining and metallurgy, various investigators have shown that intensive acoustic fields can modify the state of a mineral, leading to chemical or dispersive effects. Generally, the effect of ultrasonic vibration depends upon the nature of the mineral and also the way ultrasonic wave is applied (Celik, 1989; Ozkan, 2002). In addition, ultrasonic treatment usually plays roles of removal of reagents adsorbed layer from minerals and emulsification of flotation reagents when it is used in flotation (Nicol, Engel, & Teh, 1986; Slaczka, 1987; Djendova & Mehandj, 1992; Farmer, Collings, & Jameson, 2000; Gurpinar, Sonmez, & Bozkurt, 2004)."

Jan 1, 2016

The Millennium deposit, located in northern Saskatchewan between the McArthur River mine and the Key Lake mill, has considerable potential for becoming an operating mine. Located in the Athabasca Basin, Millennium is blessed with both the riches and the challenges that this basin offers. The potential for ground water inflows during shaft sinking, and the unconventional challenges associated with underground uranium mining, render the successful development of a new mine in this area especially rewarding. The preliminary design and engineering of the Millennium Project has tapped into the experience of other operations in the area, and has utilized new applications of geophysics technology to enhance the understanding of the local geological structure. This discussion will focus on the innovations, and the challenges specific to uranium mining, for a deposit that is poised to be one of the next mines to supplement Saskatchewan's uranium resources.

May 1, 2008

By A. Scheltema Beduin, M. Kalisch, E. Floch, R. J. Dijkhuis, H. J. Oterdoom

In metallurgical copper production, the traditional aim is to increase recovery of copper to the maximum. SMS Siemag (SMS) has supplied numerous furnaces for this application. New targets are to make sure end of line products are as safe as possible with respect to health and environment, and to maximize raw material utilization. This means a for example a minimization of leachable metals in slag, so it can be safely used as a construction material, and either a targeted concentration or fixation of volatile compounds, such as arsenic. Currently, 2 process routes are generally applied for slag cleaning. The first is grinding followed by flotation, and the second is slag cleaning in an (electrical) furnace. Popularity of both options has fluctuated over the years, and currently the milling-flotation seems to be the more popular option. In this article some of the advantages and disadvantages of both methods are described, and especially how long term environmental policies could have an impact on the decision which process route to choose. Finally, this article will describe some of the developments SMS is working on in pyrometallurgical slag cleaning that could influence the direction for the design of the copper plant of the future.

Jan 1, 2014

By Karl Houseley, Dr. Robert J. Chapman

"A gravity concentration process has been applied to ores from the Clogau Mine, north Wales, the Tyndrum deposit, central Scotland and an alluvial ore from Leadhills area of Scotland. In the case of the Welsh ore and the alluvial deposit the gold grains in the concentrate and tailings streams have been characterised in terms of their three dimensions.In the case of Welsh ore, the thickness of a gold grain has been shown to be the single most important factor in determining behaviour in a gravity concentration operation. Six indices were used to quantify the overall geometry of the gold grains and those which incorporate a thickness term have proven to be effective in predicting the destination of gold particles within the concentration circuit. It is proposed that the most simple of these, the Heywoods flakiness ratio, has potential for the control of milling operations as an alternative to the established practice of characterising the size of the mill discharge.The effect of grain geometry on the recovery of fine gold has been studied using Tyndrum ore. The recovery of gold by gravity concentration increased from 20% to 70% when the criteria used to design the milling operation was the prevention of over grinding of gold grains.The destination of alluvial grains in the concentration circuit did not show such dependence on shape, and this has been attributed to the effective classification of all the gold grains in the sample by fluvial action producing a population of similar geometric characteristics."

Jan 1, 1996

By S. J. Schofield

INTRODUCTION ONE of the greatest and most interesting problems of economic geology is to discover criteria bearing on the persistence of ore in depth. It is a question which is very much to the fore in connection with many of our important mines in British Columbia, and, as is to be expected, it is a most controversial one. The present paper, summarizing the views of the writers concerning the possibilities, in some of the mining districts of the Province, for the persistence of commercial ore to greater depths than have been, or are at present, mined, is offered as a basis for a general discussion on the subject and to call attention to the need for renewed study and research on the problem. Sooner or later-at some depth or other-individual ore-shoots become impoverished and bottom. In many mines where this has happened, either at the same or at a lower horizon, another ore-shoot, which had no surface outcrop, has been encountered and has continued downward until it, in turn, has pinched out. The Kolar (Mysore, India) gold field, for instance, presents interesting examples of this recurrence of ore-shoots at depth (1). For many years these mines have been under the management of Messrs. John Taylor and Sons. On more than one occasion they have persisted in sinking or drifting on barren quartz or along a narrow fracture for many hundreds of feet before values were again encountered. Their earliest experiment in such bold development took place at a depth comparable to that at which most mines in British Columbia are considered to be bottomed. In the past, is has been concluded that the ores in British Columbian mines do not go below approximately 2,000 feet, and to that depth only in a few instances. Consideration of the depth to which ores have been mined in the Province appears to support this view. The figures shown in the accompaning table have been gathered from various sources and are approximate.

Jan 1, 1935

By Z. Liang, Z. Q. Liu, X. F. Li, H. L. Zhang

"Dynamic characteristics of frozen soil is important for the safe, effective and rapid construction in cold regions and artificially frozen engineering. In this paper, dynamic characteristics of frozen clay with various low temperature and different strain rate were studied by using Split Hopkinson Pressure Bar (SHPB) test and numerical simulation test. Variation of dynamical parameters and dynamic stress-strain curves of frozen clay were obtained and analyzed. The results of these test show that: Frozen clay exhibits temperature effect and strain rate effect that the failure type tends from plastic failure to brittle failure with the increase of strain rate or decrease of temperature; Under impact loading, frozen clay exhibits three typical dynamic stress-strain curves as strain rate increases, and the maximum strain of frozen clay only linear increases with strain rate.INTRODUCTIONArtificial freezing technology has been widely used in the construction of underground engineering, such as the coal mine shaft, the deep foundation pit, the urban metro and subsea tunnel, etc. Research on dynamic mechanical behavior of artificial frozen soil will provide supports for these artificially frozen engineering (Xu et al. 1998; Ma 2009). However, the dynamic mechanical research on frozen soil is mainly carried out at low frequencies or small amplitudes of the waves, behavior of frozen soil under impact loads or high strain rate loads has not been made clear."

Jan 1, 2015

By Al Gagnon

Since start-up in 1972, many circuit problems have been encountered, most of which were related to the abundance of fines (-28 mesh), which the circuit had not been designed to treat. The major problems associated with the original circuit included excessive loss of magnetite, reduced throughput during periods of a high proportion of fine coal in the plant feed and low yield in the fine coal circuit. This paper outlines the coal processing circuit at Fording Coal Limited as it exists today, with emphasis on the changes to the original fine coal treatment circuit.

Jan 1, 1978

By Z. Bibak, S. Banisi, A. Ghasemi, E. Nematollahi

"The use of large AG/SAG mills in the mineral industry has been on the rise recently due to a significant reduction in the capital and operating costs for achieving significant increases in plant throughputs. The major reason for downtimes in these mills is the time taken for the replacement of broken or worn liners. This loss of “availability” of these units has a significant impact on the productivity of these plant operations. The ability to predict liner life time and its evolving shape could help to optimize these comminution operations. In the past decades, various models have been proposed to estimate liner wear rate, but because of their empirical nature they could only be used within certain limited operating conditions. In this research, a phenomenological model which could predict the liner wear rate was proposed and tested. This model considers parameters such as; operating conditions, liner hardness, pressure on the lifter, and, relative velocity of particles and mill shell. Data from industrially measured liner profiles were taken during the liner life time at the Sarcheshmeh and the Gol-E-Ghohar SAG mills to provide a solid base to calibrate and validate the model. The comparison of the model predictions with the actual measurements of the liner wear rate showed that the results were in a good agreement at both, the Sarcheshmeh (R2=0.94), and the Gol-E-Ghohar (R2=0.97) concentrators.INTRODUCTIONAG/SAG mills are one of the most important technologies in the mineral processing industry in the recent decades. The “Availability” of these units in a plant operation is one of the most important economic parameter for evaluating their performance. The major reason for the downtime of these mills affecting their “availability”, is the time required to change worn or broken liners (Yahyaei, Banisi, & Hadizadeh, 2009; Maleki-Moghaddam, Yahyaei, & Banisi, 2012). The knowledge about the magnitude and profile of liner wear not only enables more accurate liner life estimation to prevent unwanted interruptions of the SAG milling in mineral processing plants and more strategically plan the scheduled mill outages for liner changes. It also could provide key information needed to select an appropriate liner design (Yahyaei et al., 2009; Rezaeizadeh, Fooladi, Powell, & Weerasekara, 2010a)."

Jan 1, 2016