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The recovery of Copper by solvent extraction was arguably the most significant hydrometallurgical development of the 1960's. However, only dilute solutions at relatively high ph. could be treated effectively. ICVAcorga introduced in the 1970's the much stronger salicylaldoxime based reagents, which resulted in a dramatic change in plant configurations. So for example plants which normally use 3 extraction stages and 3 stripping stages could be reduced to 2 + 2 staging or 2 + 1 staging, even for high copper tenors at low ph. Leach liquors up to 40 g A copper are being treated at some locations so that almost any copper bearing liquor can now be purified by solvent extraction. Following a considerable amount of research and development effort ICI/Acorga have made further significant advances in the application of copper solvent extraction. The first of these is in computerised flowsheeting. In conjunction with ICI's Process Technology Department, Acorga have developed the Minchem Computer program, which uses laboratory generated equilibrium data to facilitate optimisation of metallurgical operating parameters. The program can operate in two modes, prediction and assessment so that given suitable extract and strip isotherms plant performance can be predicted for a given set of conditions. Alternatively existing plant performance can be assessed rapidly and accurately, thus providing a valuable quality control tool. Pilot plant work can now be restricted to evaluation of the physical aspects of the SX circuits, and to looking for the unexpected. Secondly using the patented 5-Nonyl Salicylaldoxime in precise admixture with a number of carefully selected strip modifiers, the Acorga M-range has resulted. Reagent selection from these new extractants can now be based on how the reagent can alleviate the remaining problems such as hydrolytic stability, transfer of iron, and organic losses by entrainment which may be related to particular features of the operating plant. Thus the Acorga M-range has enhanced and significantly extended the use of solvent extraction for copper, whilst refinements in the processing of metallurgical data has considerably simplified circuit design and analysis of results.

Jan 1, 1989

By Danilo Zim, Matheus Paschoalino, Denis Guimarães, Jasbir Gill

The shortage of water supply in some regions of the globe is particularly problematic and forces mining companies to adopt alternatives like pumping sea water from the ocean up to the mining sites. Although deaeration of sea water or the use of lined pipelines are known options to prevent corrosion during pumping, a recent development of a new corrosion inhibitor allowed the use of simple mild steel pipelines for this purpose. The objective of this study is to demonstrate the recent advances of this technology in protecting against not only general corrosion but localized corrosion, main cause of corrosion-related pipeline failures. Corrosion studies were carried out using electrochemical techniques, weight loss balance as well microscopy surface analysis in order to measure and therefore evaluate the treatment efficiency. The right dosage of corrosion inhibitors may vary depending on water composition and characteristics of each system. Differences were observed depending on the sea water source. Pretreatment of metallic surface impacts the observed corrosion rate which can be as low as 3.6 mpy. The absence of pitting or localized corrosion was achieved in aerated seawater.

Jan 1, 2014

By G Gibson, B Bessen

In coal preparation, large dense medium cyclones (DMC) at low pressure heads (typically 9D where D = cyclone diameter) are the norm. This contrasts with high density mineral applications where, largely for historical reasons, smaller cyclones at high heads are the standard. There are advantages in preferring large diameter cyclones at low heads, assuming that metallurgical performance does not suffer significantly. These include simpler plant layouts, easier maintenance, smaller spares inventories, reduced wear, reduced medium pumping demands, smaller buildings and overall lower capital and operating costs. In 2008, therefore, Xstrata Zinc decided to trial a single DSM-design 800 mm cyclone in one of its four DMC lines at Mt Isa, replacing the four 400 mm cyclones previously installed. Circumstances allowed a low head of 9.5 D to be trialled, compared with the existing 400 mm head of 21.5 D. This paper describes the trial, including tests using painted ore particles as tracers, estimates of yield and metal recovery, and wear monitoring. The larger unit performed well. There was no evidence that metallurgical performance in terms of metal recovery and waste reject rate suffered, and there was some evidence that it may have improved. Cyclone life increased, and preliminary data suggest that the replacement cost of the 800 mm cyclones is less than half that of the 400 mm units, and this is expected to improve. The plant layout and operability have also improved significantly. Xstrata has therefore decided to convert the whole plant to four low head 800 mm units, replacing the original 16 high head 400 mm units. The paper includes an explanation of the effect of static head on DMC separating force. It also reviews earlier research on diamond applications, and applies a general DMC process model to the Xstrata case, both of which confirm that large, low head cyclones are appropriate in mineral applications, contrary to conventional practice. Such units could significantly reduce both the capital and operating costs of DMC plants in mineral applications.

Jan 1, 2009

By Dhanaji S. Chavan, Thallak G. Sitharam

"It is well known that sites comprising of saturated loose sand undergoes large deformations, due to liquefaction, during seismic shaking. To cope with this, different mitigation techniques such as vibroflotation, deep dynamic compaction, compaction grouting, deep soil mixing etc. have been used in practice. However, as all these methods are costly, a new mitigation technique is required. Air injection has emerged as a new mitigation technique in which air is injected into the saturated loose sand. The introduced air makes the pore fluid mixture compressible and results into decrease in the generation of excess pore water pressure during seismic shaking. This paper reviews the laboratory and field studies performed to investigate the effect of air injection on liquefaction resistance. In addition to this, previous research in the direction of desaturation has evolved different techniques to generate gas in saturated sand. These techniques have also been discussed in the present paper. All the field and laboratory studies have shown that even a slight decrease in the degree of saturation increases the liquefaction resistance significantly.Keywords: desaturation, air injection, liquefaction resistance, pore pressureINTRODUCTIONEarthquake events in the past, caused liquefaction of loose saturated sands at many sites in the world. The consequence of liquefaction varied from small deformations to catastrophic failures such as flow slides, lateral spreading, sand boiling etc. (Kramer, 1996). To reduce the liquefaction potential of such soils, different mitigation techniques have emerged across the world. Some of the most widely used mitigation techniques are vibroflotation, deep dynamic compaction, compaction grouting and deep soil mixing (Idriss and Boulanger, 2008).Yoshimi et al. (1989) found that the liquefaction resistance of partially saturated sand is significantly higher than that of saturated loose sand. Further, Pietruszczak et al. (2003) proposed desaturation of the saturated loose sand as a new liquefaction mitigation technique. It is observed that the liquefaction resistance of sandy soil is enhanced significantly owing to the desaturation caused during construction of sand compaction piles (Ishihara et al. 2003). Over past few years research is being carried out on desaturation of sandy soil and its liquefaction resistance ( Ishihara et al. 2003; Okamura and Soga 2006; Yegian et al. 2006; Yegian et al. 2007; Takemura et al. 2009; Eseller-bayat et al. 2013; He et al. 2013; Marasini and Okamura 2015; Zeybek and Madabhushi 2016). As a result of this, different techniques of desaturation have also emerged. Different studies conducted in this direction and their outcome has been discussed in the section to follow."

Jan 1, 2017

By H Rossiter, C Simpson, J Market, P Jeanneau

Downhole Assay tools are a geophysical method to collect an instigated response from the material surrounding a drill hole and deliver a multielement proxy-assay. They were first tested in the Pilbara at the turn of this century, however since 2011 they have seen a more focused testing and implementation regime with multiple companies across multiple Pilbara mine sites. The increase in the volume of data has led to advances in the measurements and significant improvements to the efficiency of the calibration process. Pulsed Fast and Thermal Neutron Activation Analysis (PFTNA) downhole assay tools collect gamma photon spectra which are characteristic of elemental signatures. One of the key components of the technique is calibrating the spectral signatures to lab assays. Each tool is slightly different due to the organic nature of the crystal detector and therefore responds slightly differently. Environment and hole conditions as well as ore characteristics are among other external influencing factors. Thus, a unique calibration is required for each tool. In addition, not all elements are measured directly, but some are actually characterised by proxy, meaning that if the signal-to-noise ratio for an element is small, it may be easier to identify the mineral or geology in which that element is found and thus infer the concentration of the element. These proxies may differ for each site or geology type within a site. There is a large advantage to build a unique calibration per tool at each site rather than a universal one to be used across the whole province. This then delivers the accuracy and precision of measurements that mining companies require for modern operations. Early work with the tool required several thousand metres of calibration data and several weeks of analysis to build each calibration. This process has now been streamlined to significantly reduce the amount of data required and the analysis time to make it much easier to introduce new tools to a site with an existing model or to create new models. This paper details the calibration process, illustrating the increasing accuracy of the models as training data are acquired as well as the methods for transferring a calibration from one tool to another.

Nov 8, 2021

By Will Callupe Arzapalo

The success of the minimization of blast induced-damage at Barrick?s Pierina Mine in Peru is the result of an effective working relationship between Mine Operations and the Geotechnical Services Department. A detailed design criteria manual is used to match the blast plan to the site?s varying rock types and slope designs. The Geotechnical Services Department has further developed a comprehensive pre- and post-blast checklist that is critical to the drilling and blasting process as it pertains to wall stability. Wall control blasts are evaluated with quality assurance field checks, vibration monitoring and frequency control, video assisted performance quantification and post excavation face profiling. These detailed observations are compiled and summarized in a blast performance evaluation that is considered to be an ?Industry Best Practice?. The information and detail provided by each performance summary allows accurate blast analysis and effective design refinement.

May 1, 2006

By Mohammed Ali Shah, Martin Waller

The mining industry depends to a large extent on the availability of high performance equipment. For drilling this means a requirement for well engineered, reliable machines with mechanised handling and widespread utilisation of automatic control. Such machines enable performance optimisation of drilling operations and integration into a high productivity mining system. A review is presented of the current status of drilling technology as applied to the mining and minerals industry. This covers developments in: drill bit materials and design; drilling techniques; machine design; mechanisation; automation; and drilling control. It also covers the ways in which current and future mining methods and practices will influence the applications and demands placed on drilling activities. The probable impact of current research on the industry is discussed.

Jan 12, 1992

By S. Polegeg

The basic principle of this separation method was already defined in the middle of the nineteenth century. However, a change over for the treatment of minerals has followed from the construction of proper machines i.e. airjigs and airtables as late as in the twenties and thirties of this century. The main application of this technology was subsequently found in coal processing and reached quite a great dimension in the two following decades. The number of applications of this method in mineral dressing plants decreased rapidly and has almost vanished in the fifties in favour of wet concentration procedures. It has been for a long period as long as up to the eighties that no more consideration was taken for applying dry gravity separation in the field of mineral processing also due to the successful introduction of flotation. Due to the fact that labour cost was increasing remarkably within the past period after the end of World War II also the economic conditions in the agricultural sector became more though. As a result there came up a great demand for harvesting machines. Since agricultural products can only be processed by dry methods in a prevailing number, highly developed machines were introduced for the dry processing of food and feed stuff.

Jan 1, 1992

By Richard Weinstein, Richard Snoby

There are many advantages to upgrading coal with dry jigging technology. The most obvious is the lack of process water, which eliminates the need for fines dewatering and slurry confinement. Dry jigging eliminates the clean coal moisture penalty associated with wet processing. Particulate emissions are virtually nonexistent due to inclusions of fabric dust collectors on all modern dry jig plants. Because of the environmentally friendly nature of dry jig plants, installation permits are often measured in days, not months. There has also been a fundamental advance in dry jigging efficiency. All of these advantages have renewed the coal industry’s interest in dry jigging. But air jigging is not right for every application. There are limitations due to particle size, particle shape, moisture and near gravity content. This article explores the evolution of dry jigging. It reviews parameters important for determining the suitability of dry jigging. It also compares historical performance data as measured by imperfection, against results from modern dry jigging technology. The article also presents data from modern dry jig installations.

Jan 1, 2007

By F. S. Knoll

The expanding role of electrostatics as applied to minerals and related fields is covered in this paper. New and existing forms of electrostatic separation are classified into two broad groups: separation of charged particles and separation of neutral particles. The basis for each form of separation is discussed along with particle examples and results obtained.

Jan 1, 1986

By F. S. Knoll

Electrostatic separation is one of the most misunderstood physical processes used to beneficiate minerals. Nonetheless, millions of tons of titanium ores, iron ores and other minerals are processed every year economically, efficiently and safely. Over the past ten years major advances in electrostatic separation and its application have occurred. New processes include dewatering clay slurries, separating halite and sylvite, and shape separation of vermiculite and gangue minerals. Electrostatic separation techniques are based on one of two methods, electrophoresis or dieleccrophoresis -- processes involving charged and uncharged particles respectively. In some cases, the combination of these two techniques has proven quite useful. The purpose of this paper is to provide a basic understanding of the physical processes collectively called "electro- static separation" in order to enhance one's ability to define and consider new possibilities in mineral processing and other fields.

Jan 1, 1984

By Steve Kral

Competition in the gold mining industry throughout the world has become fierce in recent years. The challenge facing operations personnel is to produce more gold for less money. Likewise, the explorationist's charge is to find more gold in a more cost-efficient manner. That means using new technology to find new gold deposits and expand present ones. More accurate mapping instruments are available to geologists in the search for new deposits. Advanced geophysical and geochemical methods enable explo¬ration teams to review previously mined districts in their search for minable reserves. Four technical sessions on the geology, exploration, and development of gold deposits were part of the program at `world Gold '89,' a Gold Forum on Technology and Practices," held by SME and The Australasian Institute of Mining and Metallurgy in Reno, NV, Nov. 5-8, 1989.

Jan 1, 1990

By A B. Opperman

For many years explosives energy has been utilized in mining and construction as well as many other applications which are vital to our way of life. Many types of explosives have made their contribution as technology has moved forward. One of the best known was dynamite, which for many years was the mainstay of explosives users. Although dynamite had many advantages over its predecessors, it had the principal shortcomings of being somewhat hazardous to handle and was known as a headache producer.

Jan 1, 1975

Flotation works very well for particles that are typically in the range 20 to 150 µmin diameter, for base metal ores. In this range, it is possible to get quite high recoveries in conventional flotation machines. Outside this range, the recoveries decline progressively, whether it be with the very fine or the coarse end of the size spectrum. In this paper, the reasons for the drop-off in recovery are briefly reviewed, together with strategies for future work. Recent progress in the author's laboratory will be described. These include the Concorde Cell, which takes advantage of the high dissipation rates in the shock wave created when a gas-liquid mixture reaches supersonic velocities. The environment thus created is very beneficial for the flotation of ultrafines. For coarse particles, the reasons for the drop-off in recovery can be related to the highly turbulent nature of the pulp in a conventional flotation cell. To improve recovery, it is necessary to find a way of bringing particles and bubbles into contact in a quiescent environment. A new process for coarse particle flotation will be described, in which a fluidized bed is created in the flotation cell. The flow conditions are very gentle, and the high solids concentration leads to rapid rates of capture of the particles. Experimental results are presented. It is apparent that the maximum floatable size for coal and minerals can be increased by a factor often over the limits found in current practice. Advances

Jan 1, 2009

By G. T. Adel

The selective recovery of fine particles by flotation has been a long-standing problem in the mineral processing industry. Fundamental studies carried out at Virginia Tech since 1980 have suggested that many of the problems encountered in separating fine particles can be alleviated by using significantly smaller air bubbles than those used in conventional flotation processes. The main advantage of using smaller bubbles is found in an increased recovery rate, which can be attributed to an improved bubble-particle collision efficiency. This concept has been applied in column flotation as a means of improving flotation kinetics. A computer simulator has been developed to better study the effects of various parameters on flotation column performance. The simulation results suggest that the use of small bubbles and tall columns improves the recovery of fine particles while a judicious use of wash water greatly improves product quality. Information collected as a result of this analysis has been applied in developing scale-up relationships for column flotation.

Jan 1, 1989

By Jorge Rubio, Gabriel Berkowitz, Fabiano Capponim, Carlos Perez Guerrero, Elves Matiolo, Denise G. Nunes

This paper describes some advances in flotation research in fines (“F” 38 to 13 µm) and ultrafines (“UF” < 13 µm) mineral recovery by two different techniques, at laboratory scale. Extender flotation and flotation with .multi-bubbles. (bubbles with a wide size distribution) of copper sulphide fines (ore feed of about 1 % Cu) were compared with a .standardised. mill laboratory procedure. Comparative evaluation was made through concentrate grade and recovery (size by size results included), .true. (bubbles-particles attachment only) flotation recoveries and process kinetics. Both techniques yielded higher metallurgical efficiencies than the mill standard but better results were obtained with the extender flotation, with emulsified diesel oil (90 gt-1). Concentrate recoveries were of the order of 85-90 % (84 % in standard conditions), 14-17 % Cu grade (15 % Cu in the standard) and 3.5-4.5 min-1 for the Klimpel rate constant (3 min-1 in the standard). Size by size and true flotation results proved that metallurgical and kinetic gains, obtained with the two techniques, might be attributed to fines and ultrafines enhancement. Data obtained are discussed in terms of physical and physico-chemical parameters related to aggregation and capture (of particles by bubbles) phenomena and the practical potential of these techniques are envisaged.

Jan 1, 2003

By lves Matiolo, Jorge Rubio, Carlos Perez Guerrero, Denise G. Nunes, Fabiano Capponi

The problem (very old) of processing by flotation, the fine (“F”, 38-13 µm) and ultrafines (“UF”, < 13 µm) mineral particles continues to be a major technical challenge in the area of mineral processing. Many different processes have been proposed over the last three decades but, unfortunately, most of them have not found practical applications yet. This paper describes some advances in flotation research in fines (“F”, 38-13 µm) and ultrafines (“UF”, < 13 µm) mineral recovery by two different techniques. Extender flotation (EF) and flotation with bubbles with a wide size distribution-SB of copper sulphide ore fines (1 % Cu) were compared with a “standardised” (STD) mill laboratory procedure. Comparative evaluation was made through concentrate grade and recovery (size by size results included), “true” flotation recoveries and process kinetics. Copper porphyry samples, containing about 1/3 of the mass and about 37 % of the total copper content in the fines and ultrafines fractions were used. In the EF tests diesel-in-water emulsions were used as an extra reagent, added after the collector and frother addition. In SB tests, drawing air through an aspiration nozzle, directly in the pulp, generated bubbles sized about 50-200 µm. Both techniques yielded higher metallurgical efficiencies than the mill standard but better results were obtained with the extender flotation, with emulsified diesel oil (90 gt-1). Concentrate recoveries were of the order of 85-90 % (84 % in standard conditions), 14-17 % Cu grade (15 % Cu in the standard) and 3.5-4.5 min-1 for the Klimpel rate constant (3 min-1 in the standard). Size by size and true flotation results proved that metallurgical and kinetic gains, obtained with the two techniques, might be attributed to fines and ultrafines enhancement. Data obtained are discussed in terms of physical and physicochemical parameters related to aggregation and capture (of particles by bubbles) phenomena and the practical potential of these techniques are envisaged. The following figure shows size-by-size copper recoveries results, after classification of produced concentrates and tailings using micro-sieves. Results clearly show that flotation of the F and UF fractions is highly improved with injection of small bubbles (SB) and with the addition of an extender collector. It is believed that the techniques presented here will establish shortly a new basis for the flotation enhancement of the F and UF, aimed at solving a very old problem. This work is being continued, now at pilot plant scale, and results will be published en the near future.

Jan 1, 2003

The Porgera gold mine has made significant progress with the successful installation of a JK FrothCam image analysis system. The system is used to measure and control froth velocity on the scavenger circuit which has brought significant economical and operational benefits. The froth velocity signal, determined by analysis of the camera, is transmitted to the PLC that manipulates flotation cell airflow rate and cell level controllers to maintain a target froth velocity of 130 mm per second. Following on from a three-week trial installation in June 2000, a permanent installation was commissioned on the scavenger Outokumpu (OK150) tank cells. Further work is in progress on the rougher Wemco cells. This paper describes the evaluation of FrothCam Technology and its subsequent installation.

Jan 1, 2003

By T. A. Lloyd

The use of tank cells over the years has provided a means for low cost, space efficient, extra capacity in existing flotation circuits. In some cases, new plants have selected tank cells as the machine of choice. Typical tank cells use high efficiency impellers for mixing, which results in low power draw. Unfortunately, these mixers have poor aerating characteristics that compromise metallurgical performance. This has all changed with Outokumpu&apos;s new flotation concepts. Outokumpu has recently developed the HG or High Grade flotation cell that can provide higher recovery with better selectivity while maintaining the simple operation of conventional cells.

Jan 1, 1993

By S. Frisch

Selenium (Se) in effluent waters has become a significant challenge for a number of industries. Toxicity studies and new reports of occurrence have certainly caused increased scrutiny and actions in the mining industry today (Sandy, DiSante, 2010). While initial activity in addressing selenium-laden waters were conducted in the coal mining industry, today a much broader range of mine types are beginning to search for solutions to selenium treatment of their mining waters, including both hard rock mining operations (gold, nickel, zinc, etc.) and soft rock mining (phosphate, uranium, etc.) Throughout North America, new regulations covering selenium discharge are either in place or being developed. While a number of physical/chemical approaches show promise in selenium treatment, when considering optimal cost and treatment efficacy issues, biological treatment ? particularly fixed-film biological treatment - is reported to be one of the most promising approaches to managing selenium-containing waters. Among biological treatment options, the fluidized bed reactor (FBR) has undergone extensive pilot testing for Se treatment in the last three years, including eight pilot programs, and the first FBR system is now operating at a coal mining site. In all tests, the FBR has been shown to be a highly cost-effective approach to selenium treatment based on its physical and performance characteristics. This is consistent with its history for reaching low levels of treatment in similar service for other oxyanions including perchlorate, nitrate and various metals. With the results from the most recent testing, the technology has been shown to be adaptable to an ever-broadening range of influent water conditions and flow rates, in varying terrains and weather conditions. Selenium occurs in various valence states from -2 to +6 (Sobolewski, 2005). The speciation of selenium plays a critical role in understanding the effectiveness of any approach for removal, especially to low levels. Elemental selenium is insoluble and has little effect on living organisms. Colloidal fractions are known to occur. In aqueous environments such as coal mining runoff, selenium is most often found as the oxygenated anions of selenite (SeO32-, Se4+) and selenate, (SeO42-, Se6+). Selenium is commonly found in mining waters in concentrations ranging from 3 to >12,000 µg/L. The U.S. National Primary Drinking Water Standard MCL is 50 µg/L for selenium (EU 10 µg/L; WHO 40 µg/L). The National Fresh Water Quality Standard is 5 µg/L for selenium. The U.S. Fish and Wildlife Service has recommended that the National Fresh Water Quality Standard be lowered to 2 µg/L to protect fish, waterfowl, and endangered aquatic species. Several states have followed with enforcement actions at these same low levels. In Canada, permits may require stakeholders to monitor levels in water or biota, or to comply with guidelines, at either the National or Provincial levels, which can be as low as 1 or 2 µg/L in surface waters. Treatment of selenium in all mining waters presents a series of challenges. It can be present in relatively dilute concentrations and in streams with variable and often high flow rates. It can be present in many soluble and particulate forms, which may affect process design and treatability. The conditions of influent selenium-containing waters can vary, with issues such as temperature, pH, total dissolved solids and other contaminants affecting the ability to remove selenium selectively and economically. Treatment of selenium often results in the generation of a concentrated by-product requiring disposal, and re-release from residuals can occur. Beyond these issues, the physical environment of a mining operation can offer challenges such as remoteness and harsh and/or cold weather. Currently available selenium treatment technology (Table 1) includes biological treatment and a number of physical-chemical processes ? such as ion exchange, membrane filtration and adsorption ? that vary widely in efficiency and cost. Most treatment options remain either too costly and/or unproven for selenium-containing streams for reasons that include poor removal efficiency, variability in volume and composition of influents, system sizing and logistics considerations, as well as operating requirements.

Feb 23, 2014