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By J. Rabe

Tasked with developing a flow sheet for a new resource, one typically turns the experts for help. The advice of an expert can be invaluable in reducing the time and costs associated with characterizing an ore (not to mention extracting maximum information from limited samples). While guiding and optimizing a metallurgical concept study requires a certain skill set, selling a project is something different. The metallurgical specialist is usually not responsible for sharing the results of investigations with potential investors. However, the person responsible for selling the project can ensure that a metallurgical concept study is conducted thoroughly and responsibly without having the ability to do the work, while being sufficiently familiar with the metallurgical aspects to authoritatively sell the project. The process of identifying suitable process routes through to constructing a concept flow sheet and mass balance is discussed as a basic example. From basic mineralogical information and a thorough literature survey, the most likely beneficiation routes can be identified and targeted testing conducted. The final top size will depend on the required product properties (mainly grade), the selected beneficiation technology, and the ore?s liberation properties. Once the required top size has been identified, comminution options can be evaluated. Once again, literature surveys can be used to supplement concept-level comminution property information, and select possible equipment and circuit configurations. Marketing, material handling, and logistics-related information can be used to determine required dewatering technologies. At this stage, enough information is available to develop a concept mass balance and conduct basic equipment sizing..

Jan 1, 2014

Production caving started for Lift 2 at Northparkes in August 2004. In a period of less than 3 months, more than 10 000 seismic events were recorded. Events up to local magnitude +2.9 were induced near the mine during caving, with event rates of up to 500 per day. This paper documents the seismicity related to cave initiation and cave propagation during the initial production of Lift 2. The seismogenic zone of events initially moved at a rate of about 0.5 metres per day, accelerating to 2 to 3 metres per day after a few months of cave production. Seismic data analysis infers that the crown pillar between Lift 1 and Lift 2 was destressed over a vertical height of about 100 metres. As the seismogenic zone approached the crown pillar, a macroseismic episode occurred, with more than 20 events of at least local magnitude +1 occurring in a two-week period. Based on the seismicity recorded for Lift 2 at Northparkes Mines, a caving mechanics model is proposed. Comments and suggestions are made for seismic data analysis and design of seismic monitoring systems in block caving mines.

Jan 1, 2008

The inherent weakness of the Zincor and similar iron removal processes is the relatively high undissolved zinc loss associated with the iron residue. High soluble zinc losses also occur due to poor filterability of the iron residue even though it may be limited to intermittent events. This work focussed on defining the optimum operating window for the Zincor iron removal process where iron is mainly removed in the form of amorphous, intermediate iron phases such as schwertmannite and ferrihydrite. In terms of the main operating conditions, optimum filterability was achieved under the following conditions: pH of 3.0, temperature as high as practically possible (70C), at least 25 kg/m3 seeding, and a retention time of at least 4 hours. When increasing the temperature from 60C to 70C, the required residence time decreased by almost 50%. Undissolved zinc loss was also reduced from 8% to between 2% and 3% by using a basic zinc sulphate/zinc oxide mixture as neutralising agent to effect iron removal.

Jan 1, 2003

By C. B. Espag de Klerk, J. de Goede, M. Le Roux, Q. P. Campbell

"Excessive amounts of moisture in product coal can influence the efficiency of downstream utilization processes due to a decreased calorific value and handling problems. Stockpiles can be used to decrease the moisture content of coal by means of gravity drainage and evaporation. This paper is focused on the evaporation of moisture from a coal stockpile surface with the aim of investigating the effect of particle size on the rate of evaporation as well as the depth to which evaporation extends.It was observed that moisture initially evaporates at a higher rate from a stockpile consisting of fine particles (-6.7 mm) than from coarser particles (-13.2 mm +6.7 mm). This high rate of evaporation is restricted to the outer shell of the fine coal stockpile. However, for coarse coal, the porous nature increases the depth at which evaporation occurs. Evaporation of moisture was observed up to the fourth day of each experimental run, after which steady state was obtained. It was shown the water can evaporate from the surface into the body of the stockpile, depending on the coal particle size and void spacing. An experimental reclaim depth of 0.4 m was achieved after 4 days. IntroductionCoal stockpiles serve as surge capacity for downstream utilization processes and can also be used for moisture reduction by means of gravity drainage and evaporation. Excessive amounts of moisture in coal can cause handling problems and, most importantly, will decrease the calorific value, leading to inefficient combustion.Research has shown that evaporation by means of wind and solar action is considerably more effective than gravity drainage(Williams, D.J. 2006), but the effect is limited to a restricted depth from the exterior of the stockpile (Boyapati, E. and Oates, A. 1994; CSEM-UAE, 2010). The effectiveness of wind and solar action can be improved by orienting the stockpile perpendicular to the predominant wind direction, maximizing the surface area of the pile, and reclaiming the coal from the pile gradually in shallow cuts over a large area (Williams, D.J. 2006)."

Jan 1, 2016

This paper presents recent advancements in the MillMapper software technology, developed and used for thickness gauging of liners of cylindrical grinding mills used for mineral comminution. MillMapper uses calibrated laser scanner data captured inside a mill to determine thickness at several million points on all liner surfaces with millimetre accuracy. The paper is structured as follows. First, a review of the technology and its numerous advantages over existing techniques and the value it adds to operations are presented. These are followed by discussion of recently-implemented innovations, including improved visualisation and inspection tools, automatic ball charge volume measurement and automatic mill liner volume/weight measurement. Results from its application at several sites in Australia are presented throughout.

Jan 1, 2007

By P. Ramsaywok, G. Legodi

Spiral concentrators are widely used in the coal industry treating fine (-1mm) coal. Their application was a limitation to the product quality until the introduction of low-cut spirals which allow a lower quality ash product to be produced, thus expanding the market. The Exxaro Grootegeluk 1 (GG1) plant has a two-stage traditional rougher-cleaner spiral circuit using conventional SX4 spirals to produce semi-soft coking coal product at 12.5% ash by mass. The overall plant product is 10.3% ash meaning that the coarser sized coal dense medium separation circuits must compensate. A low density cut-point spiral targetting 10.3% ash would thus be beneficial to the overall complex. The spirals were tested in the two-stage plant environment and in a pilot plant. This paper discusses the findings and compares a two stage four-turn low density cut and conventional spiral. The two spiral technologies were unable to sustain a 10.3% ash product. Pilot test work was also conducted on GG1 coal, demonstrating that an eight-turn low density cut-point spiral achieves the targetted 10.3% ash under controlled conditions. Keywords: Spiral, low-cut, coal

Jan 1, 2020

By J. Du, V. Shukla, C. R. Kumar, U. Shivangi, D. P. Chakraborty

During the processing of iron ores, a large quantity of low-grade tailings containing abundant iron values in fine particle size range is produced. Due to the increasing demand in the high-grade ores for metallurgical operations and the stringent environmental conditions imposed on mining activity, it is essential to utilise the waste tailing pond slimes. Recovery of iron values from these tailing ponds not only enhances the life of the existing operating mines, but also enables achievement of a sustainable process. Iron ore tailing/slime (-150 μm) is produced after scrubbing and wet screening of a low-grade iron ore. Tailing beneficiation of iron ore has been addressed either by flotation or wet high intensity high gradient separation. The present paper aims to recover iron values from discarded slime containing assay ~56% Fe, ~6.5% SiO2, and ~7.0% Al2O3 from the Noamundi processing plant by using a high gradient magnetic separator (HGMS). In this process, tailings are effectively processed with a vertical pulsating high gradient magnetic separator to produce a relatively high-grade iron concentrate. The results of investigation indicate that this novel process is capable of producing an iron concentrate assaying ~ 60% Fe and ~3.25% alumina with a yield of ~55 % on weight basis and recover > 65 % iron bearing particles from the tailings. More importantly, the corresponding tailing contained ~45% Fe. It was concluded that this novel process may be effectively used to recover iron values from low-grade hematite tailings. Keywords: Iron ore slime, Fe recovery, HGMS, yield, Noamundi

Jan 1, 2020

By L. Thomas, A. Argyn, B. Mbao, G. Longo Banza

Since the first application of solvent extraction as part of the hydrometallurgical processing of copper, several studies have been carried out to optimize extractant formulations. In 2006, Solvay developed the ACORGA® OPT series of solvent-extraction reagents to optimize copper transfer by use of a blended formulation containing both aldoxime and ketoxime as well as selected modifiers. The incorporation of selected modifiers in these blended reagents resulted in increased copper transfer, due to the interaction between the modifier and oximes within the blend. By changing the ketoxime concentration and ratio of modifier to aldoxime, the strength of the formulation was optimized to enhance copper transfer and improve Cu:Fe selectivity. This formulation is well known in the African region under the ACORGA® OPT5540 name and provides the best performance at the conditions of agitated leach plants with pregnant leach solutions that fluctuate in Cu grade and pH. This paper discusses advantages of using ACORGA® OPT5540 in the Copperbelt

Jan 1, 2023

By I. Nolet

Matte tapping is one of the most critical operations of a matte smelter. Every smelter has developed particular matte tapping practices and tap-hole repair strategies that are often based on the experience of the smelter personnel. As a result, very little information has been published on these critical topics. This paper aims at providing the information gathered from a survey conducted in the PGM and Ni industries on matte tapping practices and tap-hole maintenance strategies for different PGM-Ni matte smelting operations.

Jan 1, 2014

By O. A. Olaseinde

The 2101 lean duplex stainless steel has wide potential application in storage, heat exchangers, and in the oil and gas industries. This work investigates the electrochemical behaviour of 2101 duplex stainless steel with an addition of 0.15 wt% ruthenium, using potentiodynamic techniques in 1M H2SO4 at 25º, 40º, 60º, and 80ºC. The microstructures of samples were characterized using optical metallography and scanning electron microscopy. The results showed that the ruthenium addition moved the corrosion potential of alloy 2101 to a more positive potential. All samples containing ruthenium displayed longer passive regions at 25°C and 80°C compared to those without ruthenium. Alloys without ruthenium had higher critical current density (icrit) values when compared to the alloys with ruthenium. Ruthenium additions decreased the passive current densities and inhibited anodic dissolution. At room temperature the corrosion rate of alloys with ruthenium was lower than these without ruthenium.

Jan 1, 2012

By H. C. Van Der Merwe

In the 21st century, dynamic, accurate digital 3-D geological models are essential to the pursuit of safe, efficient and profitable mining. This is particularly true for the deep-level underground mines in South Africa. The Sirovision® solution is a collaboration project between the Australian CSIRO (Commonwealth Scientific and Industrial Research Organisation), Datamine Software Ltd. and AngloGold Ashanti Ltd (AGA). The purpose of the project is to provide a fully integrated digital rock face imaging, geological mapping and modelling system for the AGA gold mining operations. The CSIRO-developed Sirovision® Stereo Camera Rig (SCR) consists of two digital cameras, alighting system, a laser guidance system and image processing software. The imaging system works on the principles of photogrammetry, i.e. overlaying of two 2-D images with a central focus point, with mathematical algorithms extracting 3-D information from the 2-D image pair. The output from matching several image pairs is a computer-generated, full 3-D, virtual copy of the mining excavation. The image resolution and relief ares of sufficient quality to distinguish different rock types and structural contacts. Functionality within Datamine Studio3 is used to add geological intelligence to the 3-D images provided by Sirovision®. The geologist identifies and ?draws? lines representing geological features directly onto the image. By utilizing the inherent ?topography? of the 3-D image, the software is able to convert the lines into 3-D surfaces, ready for use in the 3-D geological model. Subsequent to promising underground test results from AGA?s Sunrise Dam Gold Mine (SDGM) in Australia and other mining operations worldwide, it was decided to test the Sirovision® system in the South African deep-level gold mines. The first underground tests at Moab Khotsong Mine began in January 2009. The objectives of these tests entailed the capturing of 3-D images of selected development ends, mapping of geological features onto the 3-D images and integration of the mapping data with the 3-D geological model. Some downsides have cropped up during the feasibility testing, related to practicality of the SCR for acquisition of 3-Dimagery in the deep-level underground operating environment. These constraints will have to be addressed prior to operational implementation. Facing such difficulties is not unusual when attempting to implement new technology in such a challenging working environment and testwork is still in progress at the mine in order to prove the concept of using this technology in a Witwatersrand underground gold mine. The great advantage of the Sirovision® solution is that it offers the geologist the opportunity to work remotely on a 3-D virtual copy of a mining excavation, without the heat, humidity, hazards and time constraints associated with physical mapping in an underground workplace.

Jan 1, 2009

By F. Nakhaei, A. Noury, S. Ghodrati

To achieve maximum efficiency in any purification stage, the flotation should be continued until the concentrate grade reaches the feed grade. During sampling from rougher cells of the Iranian Sarcheshmeh copper concentrator plant 1, it was revealed that the concentrate grade of the last five cells of rougher circuit was close to feed grade. Therefore, it was suggested that the concentrate of the aforementioned cells be mixed with rougher feed. In this study, one of eight rougher circuit rows was selected and evaluated. The floatability tests were performed to compare the flotation behaviour of rougher feed and mixture of concentrate of the last five cells with rougher feed in the laboratory scale by a tree analysis process. The results showed that mixing of rougher last five cell concentrate with feed has a detrimental effect on flotation efficiency that leads to a 3% decrease in recovery. It was also observed that with grinding of this concentrate, recovery can be improved. Keywords: Efficiency, flotation, rougher, tree analysis, floatability, concentrate, mixing

Jan 1, 2020

By M. Izadi Yazdan-Abadi, S. H. Amiri, M. Ramezanizadeh, M. Bazmandeh

Iron ore concentrate is used as the fresh feed of pelletising plants. The green pellet properties depend on iron concentrate characteristics such as particle size distribution (PSD), specific surface area (Blaine value), iron grade, moisture content and grinding methods. The grinding methods affects particle size distribution and Blaine value. To find out the effects of grinding methods on pelletising process, green pellets were produced with concentrates that were reground by means of HPGR (high pressure grinding rolls) and ball mill. The Blaine values of ground concentrates in both types of milling were approximately 1400, 1600 and 1800 cm2/gr. The results of green pelletising tests on a pilot plant scale showed that at the same Blaine values, drop numbers of green pellets produced by ground concentrate inside HPGR were higher than the green pellets produced by ground concentrate inside a ball mill. Also, reground concentrates by means of HPGR, in comparison with ball mill, caused the production of green pellets, at higher wet and dry compression strengths. As a result, it was found that preparing the pelletising feed by means of HPGR led to more positive effects on the properties of green pellets. Keywords: Ball mill, HPGR, green pellet, drop number, wet and dry compression strengths

Jan 1, 2020

By R. Kumar, N. R. Mandre

"The beneficiation of iron ore slimes by selective flocculation was studied. Polyacrylamide (PAM) and guar gum were used as flocculant, along with sodium hexametaphosphate (SHMP) as a dispersant. The samples collected were initially subjected for chemical and mineralogical studies. The mineralogical studies indicated the presence of haematite and goethite as the principal iron-bearing minerals, with quartz and kaolinite as gangue minerals. The selective flocculation tests showed that the Fe grade can be enhanced from 58.24% to 64.60% Fe at a recovery of 66.33% using polyacrylamide as the flocculant. A Fe grade of 63.20% at a recovery of 68.04% was obtained using guar gum as flocculant. The efficacy of the studies was analysed using a separation index, which indicated that the higher separation index was obtained with the tests employing polyacrylamide as the flocculant. IntroductionIndia is endowed with huge reserves of highgrade iron ore and is one of the prominent producers in the world. As the high-grade iron ores have been exhaustively mined, it has become imperative to use low-grade iron ores, fines, and slimes to meet the growing demand. Also, generation of fines and slimes during mining and processing contributes to loss of minerals to the extent of 30% of the total value (Mandre and Panigrahi, 1997). These fines/slimes are often discarded as waste into tailing ponds, containing considerable amounts of iron. Therefore beneficiation of tailings/slimes has become necessary for optimal utilization of the resources.In recent years, interest in recovery of valuable minerals from low-grade ores, slimes, and tailings has increased worldwide. These activities are initiated not only to recover minerals but also to address various environmental issues associated with fine particle treatment. The literature reveals that several technologies have been employed in this regard, including flotation, advanced gravity separation, and high-intensity magnetic separation. However, these processes are found to be ineffective for fine particle treatment due to lower collision probability in flotation, decreased gravitational effect in gravity separation, and reduced drag force in magnetic separation, among other factors (Batisteli and Peres, 2008; Das et al., 2007; Dworzanowski, 2012; Rocha, Caneado, and Peres, 2010). Therefore, it is in this regard that selective flocculation has gained importance in treating slimes in recent years."

Jan 1, 2017

By J. K. Williams, M. P. Wells

"As part of the planning system at each division of Nchanga Consolidated Copper Mines, Limited, the Mine Planning Department is required to produce a detailed production schedule for each shaft.Because of the difficulties in producing a schedule which satisfies all the mining constraints, and because of the large clerical effort involved, the full range of possible schedules can never be considered.It has been found possible to produce a schedule using linear programming which satisfies the majority of the many varied mining constraints. Computer programs have been written to enable the mine planning department to use this mathematical system without assistance.The system has a large degree of flexibility to enable the planner to include conditions which cannot be incorporated readily in the linear program. This system permits the more efficient production and evaluation of schedules and reduces the amount of clerical effort."

Jan 1, 2014

By R. G. Coyle

"In an earlier paper the author explored the consequences of price-stabilizing effects, on an industry-wide basis, of various production strategies. These ideas have now been applied to an illustrative case of an individual mine. It is shown that the turning of production and financial policies can affect financial performance over a five-year period by as much as 22 per cent.No generality is claimed for the results and they would differ from mine to mine. It is, however, asserted that the results show that the proper turning of production, reserves and financial policies are more critical determinants of mine performance than has been realised. It is also asserted that the methods of dynamic analysis are the most appropriate means for studying this policy-design problem."

Jan 1, 2014

By I. Mc Dougall

Water-cooled copper tap-hole blocks provide an effective means of extending the life of tap-hole refractories, as the lower temperature of the refractory material inhibits wear and other damage and promotes the formation of a protective frozen slag layer. This is particularly beneficial during prolonged tapping cycles. The copper block forms an integral part of the lining, and provides mechanical support to the refractory, facilitating rapid replacement of tapping channel bricks without disturbing the surrounding lining. Safety considerations are an important design factor, and the positioning of the water channels is optimized to prevent leaks although the copper is not in direct contact with the molten fluids during normal operation. Water-cooled copper blocks designed by Tenova Pyromet have successfully been utilized on metal, matte, and slag tap-holes for a number of processes, including nickel, platinum group metals, and mineral wool.

Jan 1, 2014

By F. S. Hoseinian, B. Rezai, E. Kowsari, M. Safari

In order to remove heavy metal ions from a large volume of wastewater with a low ion concentration, ion flotation appears to be promisingly effective. In the ion flotation process, because of the high ion removal percentage, the amount of water recovery percentage is a very important factor which determines the process efficiency. However, ion flotation suffers from relatively high collector concentration to achieve the high removal percentage to the desired limit, which subsequently increases the water recovery. In this study, functionalised graphene oxide (FGO) was synthesised, using a chemical method in the ion flotation process, applied as a collector for increasing process efficiency by reducing the collector consumption and water recovery. The high ion removal was achieved with both collectors of sodium dodecyl sulfate (SDS) and FGO, while the water recovery with a collector of SDS was 3.4% higher than that with a collector of FGO. The results indicated that the FGO could be effectively used for high ion removal and low water recovery in the ion flotation process. Keywords: Ion flotation, synthesised collector, ion removal, wastewater, water recovery

Jan 1, 2020

By M. Holuzko, Y. R. Zhang, J. Alexander

The use of dual-energy X-ray transmission (DE-XRT) technology in the mining industry has been developing rapidly in the past decade. In many projects, DE-XRT images are analysed to classify ore and waste in sulphide deposits where the sulphides and non-sulphides have distinct characteristics in density. In the current practice of DE-XRT image processing, every pixel in the image gets classified into two categories, depending on the intensity of the pixel from both low and high energy X-ray response. If the pixel’s intensity is above the threshold curve generated in the high-energy and lowenergy scatter plot, it is classified as “higher density” material, and the remaining pixels are classified as “lower density” material. This paper elaborates on an alternative approach to DE-XRT image processing for in-depth characterisation of samples from a lead-zinc sulphide deposit. The detailed characterisation is achieved by providing density distribution of individual rock using DE-XRT laboratory sorting unit (COMEX) located at the University of British Columbia. Instead of classifying the X-ray images into two different classes from one threshold curve, multiple density classes are created between two threshold curves to generate the density distribution. By manipulating the two threshold curves, we can analyse images of samples obtained at different resolutions of density distribution. If the two threshold curves become infinitely close to each other, it will create a single-threshold scenario similar to the current methods being used in the industry. This method provides the ability to change the threshold curves, hence providing more flexibility on material characterisation based on the needs of the operation. Furthermore, the DE-XRT images from individual rock specimens are compared to the test results from hand-held X-ray fluorescence (XRF) analyser as well as assays of various elements for the same set of samples. The data analysis will provide information regarding ore characteristics and also the theoretical performance of the sensor-based sorting. Keywords: Dual-energy X-ray Transmission (DE-XRT), X-ray fluorescence (XRF), ore characterisation, density distribution

Jan 1, 2020

By Xiang-nan Zhu, Hao Zhang, Lin Li, Jun Qiu, Yue-xian Yu, Chun-chen Nie, Xian-jun Lyua

Waste printed circuit boards (WPCBs) are excellent metal resources. Mineralogical characteristics of different components in WPCBs were analysed in this study. Organic-enriched particles, fibreglass-enriched particles, associated particles and metal-enriched particles were obtained by density gradient method. Subsequently, the elemental composition, morphology, dissociation characteristics, functional group composition and phase composition of different components were analysed by X-ray fluorescence spectrometer (XRF), scanning electron microscopy and energy dispersive spectrometer (SEM+EDS), infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Elemental analysis results show that Cu is mainly contained in metal-enriched particles. SEM+EDS analysis results demonstrate that ideal dissociation can be achieved when the WPCBs are broken to -1 mm. Organic matter particles are enriched with carbon and oxygen elements, while fibreglass particles and associated particles mainly contain Al and Si elements, verified by XRD analysis. FT-IR results show that hydrophilic and hydrophobic groups exist widely in all components, caused by widespread organic matter. This study reveals the important properties of different components in WPCBs, which is of great significance for the subsequent separation process. Key words: Waste printed circuit boards, mineralogical analysis, elemental composition, dissociation; phase analysis, functional group composition

Jan 1, 2020