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By F. Ford, J. Dong

"Laboratory and miniplant testwork was carried out to reject uranium from an Iron Oxide Copper Gold (IOCG) deposit that contains an average of 60-70 ppm uranium with high variability. The dominate copper bearing mineral is chalcopyrite with minor bornite and trace covellite. The main gangue minerals are iron-rich chlorite, quartz and magnetite. The main uranium-containing mineral is uraninite (UO2). Downstream processes require the maximum uranium level of no more than 80 ppm in final copper concentrate.Mineralogical examination reveals that uraninite particles are finely disseminated with grain size of less than a few microns in the deposit requiring fine regrind in order to liberate uraninite from chalcopyrite particles. A lab flowsheet was developed to include ultrafine regrind of the rougher concentrate to the particle size of 80% passing 11-13 µm with up to four stages of recleaning in flotation columns. Finer regrind to 80% passing 5-6 µm may continue to improve liberation but does not decrease uranium level in the final concentrate. In each of the successive recleaning stages by flotation column after fine regrind, uraninite is rejected into the column tailings, with the final copper gold concentrate containing less than 70 ppm uranium from a feed containing 83 ppm uranium. The conceptual flowsheet was further tested in an integrated, continuous miniplant showing average 94% copper recovery with average 74 ppm uranium. The uraninite particles that report to the final concentrate are either locked with chalcopyrite or entrained as liberated particles of less than 5 µm in size.IntroductionIron Oxide Copper Gold (IOCG) deposits are copper and gold ores hosted within a large body of iron oxide and are significant ore deposits for copper and gold (Williams, et al., 2005). These deposits can also contain economic levels of other metals such as uranium and rare earth elements. The known sizes of IOCG deposits range from 10 to 4,000 million tonnes with grade of 0.2-5% copper and 0.1-3 g/t gold. One of the greatest IOCG deposits is Olympic Dam in South Australia. It is the fourth largest copper deposit and the largest uranium deposit in the world. Gold and silver in the deposit also contribute significantly to the total revenue."

Jan 1, 2017

Safe underground mine backfilling with hydraulic fill requires efficient fill drainage and stable fill retaining walls or bulkheads. If any or both the above two requirements are not satisfied, such a backfilling operation creates unsafe conditions and may lead to backfill retaining wall failures. Mine backfill retaining wall failures are always associated with economic losses, fatalities and interruption to mine production. Mining industry wants to either reduce or eliminate these fill retaining wall failures. The fill retaining wall failures could be effectively avoided through the use of fibre reinforced shotcrete fill retaining walls and engineered drainage systems through the retaining walls. This paper presents the experience of the author in developing, implementing, and monitoring several hundred fibre reinforced shotcrete fill retaining walls at a mine in Australia with the highest safety standard. The details on the mine backfill drainage system and fibre reinforced shotcrete fill retaining wall designs are also presented.

May 1, 2007

By A. H. Winckers

"The San Nicolás deposit is a complex fine grained polymetallic volcanogenic massive sulphide deposit located in central Mexico.Metallurgical testwork was carried out in 1999 and 2000 to develop a flowsheet. During the course of the metallurgical testwork it became evident that it would be impossible to develop an accurate head gradehecovery based model for the projection of metallurgy. It was suspected that variability in mineral texture was a predominate factor affecting metallurgy. For this reason it was decided to evaluate the applicability of QEM*SEM technology to this test program.This paper summarizes the metallurgical testwork and describes the evaluation and subsequent application of the QEM*SEM technology to characterize the mineral texture throughout the deposit. Finally it is shown how the QEM*SEM data are used in the mine block model to project the metallurgy.The QEM*SEM (Quantitative Evaluation of Minerals by Scanning Electron Microscopy) is an automated image analysis system developed by CSRO which provides quantitative numerical estimates of the compositional and textural properties of the mineral suite which govern the concentration process.INTRODUCTIONThe San Nicolás deposit, was discovered in 1997 through the application of geological and geophysical techniques. The property lies 60 km southeast of the city of Zacatecas on the central Mexican plateau as shown in Figure 1."

Jan 1, 2002

By Anna M. Ferrero

Stability condition of underground excavations have to be assessed to guarantee safe operations within the quarrying working areas. This objective requires a reliable assessment of the rock mass natural state of stress and of the stress redistribution induced by the excavations. This goal is often complicated by difficult geological conditions induced by tectonic stresses, complex topographies and large and irregular excavation geometries. Consequently, the acting state of stress needs to be measured by specific in situ measurement devices. This work refers on an in situ measurements campaign carried out by CSIRO tests in an underground quarry located in the Carrara marble basin. The difficult path carried out for interpretation of the measurements is described in this paper. In particular, the numerical modeling performed using the Boundary Element Method (BEM) first, to study the influence of both surface topography and excavation geometry and then the Distinct Element Method (DEM) to evaluate the influence of rock discontinuities in the measurement zone are illustrated in this work. Parametrical analysis of the rock mass mechanical features is also described in order to calibrate the numerical models and analyze the experimental results. The work has been carried out trough several phases, which are: characterization of the rock mass through geostructural surveys: this allowed us to classify the rock mass and determine the mechanical and physical parameters necessary for modeling; on-site measurement of stress levels through the application of over coring techniques; numerical analyses for the simulation of excavation phases, using the Examine3D (BEM) engineering analysis code. comparison between the measured stress levels and those numerically calculated and subsequent calibration of the BEM model; Numerical model of the forecasted excavation based on the calibrated (BEM) model.

May 1, 2009

By Dave Rose, David G. Meadows, Mike Westendorf

"Copper Mountain’s concentrator was commissioned in May 2011. The circuit consists of a 34’ x 20’ EGL SAG mill, a Raptor 900 pebble crusher and two 24’ x 39’6” ball mills. Each mill is equipped with a 2 x 8500 HP dual pinion drive system. The plant was designed to process 1585 mtph of SAG feed. From startup, the mill struggled to meet the required production rates. Over time, a major initiative that involved blasting and fragmentation, optimization of the SAG mill in terms of discharge grates, ball size and slurry density, and operation of up to three mobile pre-crushing plants resulted in significant increases in throughput. In parallel, a number of modeling tools, including JK SimMet, were run based on plant benchmarking exercises. Samples collected at the mine site during ramp up confirmed the very competent nature of the ore with drop weight - A*b values of less than 24 being recorded on a variety of plant feeds and lithologies. After due consideration including demonstration of proof of concept, a new pre-crushing circuit incorporating an XL2000 cone crusher and associated screening equipment was designed, constructed and commissioned at the site in August 2014. This paper reviews the history of the original circuit design, the various optimization steps taken and impacts, together with the final pre-crushing circuit and net results.IntroductionThe Copper Mountain Mine is located approximately 20 km south of Princeton, British Columbia, Canada (refer to Figure 1). The region has a long history of copper mining dating back to 1923. The Copper Mountain camp occurs in the 'eastern volcanic belt' of the Nicola Group (Monger, 1989). It is an alkali copper-gold deposit in which the volcanic strata are intruded by early Jurassic dykes, sills, irregular plugs and zoned plutons (Woodsworth et al., 1992). The stratified rocks are relatively fresh with slight metamorphism in the local contact regions."

Jan 1, 2016

By Hamid-Reza Manouchehri

Mining & Sustainability? A Paradox?! ? Production: gradually or exponentially increasing (giant mining) ? Ore Grades: gradually declining, ? Open Cut Mining: now widespread, likely to be sustained in the future though the long-term is hard to predict as new mineral deposits are likely to be deeper ? Waste Rock / Overburden: increasing rapidly, likely to be sustained in the future and closely linked to open cut mining, especially for coal and base metals ? Economic Resources: commonly increasing but some remain stable or gradually declining, future is linked closely to exploration, technology and economics; Increasing population, changing life style and technology development, ultimately result in sustainability in mining industry to hang in the balance and continue.

May 1, 2013

By Nilce Alves Santos, Vânia Lúcia de Lima Andrade, Keila Lane Carvalho Gonçalves, Harold Wyslouzi1

"When confronted with the difficult decisions on advancing an exploration project to the feasibility and construction stages, it is important to know how various regions of the ore body will react in the milling and concentration processes. While bench scale test work is common and inexpensive, the results and information provided are somewhat limited due to the difficulty in accurately predicting the effects of recirculating middling streams or gradual changes in solution chemistry.Conventional Pilot Plants, processing 100 to 1,000 kg/hour of sample ore, provide the detailed engineering data required to develop a final process flowsheet and to size the equipment. They are, however, expensive to set-up and operate, and are really only viable for major projects that are well advancedIn the latter part of 1999, the Mineral Development Center at CVRD (MDC) purchased a new piece of mineral processing equipment which can run continuous flotation tests using drill core samples. To evaluate its performance, and to compare it with conventional testing methods, various types of flotation tests were carried out using two different types of copper ore. The limitations and advantages of open circuit and locked cycle bench tests, as well as the Mini Pilot Plant and the Conventional Pilot Plant were evaluated.Open circuit tests carried out at the bench scale only provide basic information. More complete and trustworthy information is obtained, in terms of the recirculation of flows and reaching a permanent and stable flotation regime, as the dynamics and complexity of the tests increases. The data obtained showed that the MPP’s metallurgical performance was equivalent to that of a conventional pilot plant."

Jan 1, 2002

By Donald Leroux, Dave Scott, Giovanni Di Prisco

"The Lady Loretta lead-zinc deposit in Northwest Queensland, Australia contains an average of 5.9% lead, 17.1% zinc and 97 g/t silver. Ore mineralization is mostly comprised of fairly complex intergrowths of pyrite, sphalerite and galena. Starting in 1998, Noranda Inc., the major joint venture partner of the project, conducted extensive metallurgical test work, which culminated in July - August 2000 in a series of Pilot Plant tests. A common thread to all the metallurgical work has been the deportment of a large portion of silver into non-payable metallurgical products. Average silver distribution from four Pilot Plants shows a distribution of silver in lead concentrate of 28%, whereas silver in zinc concentrate was 49%, and 23% in the final tails.The consistently poor silver recovery as well as the fairly unusual silver distribution, particularly in zinc concentrate, was considered an issue to be thoroughly investigated. A mineralogical plan was devised to determine if these particular metallurgical results were somewhat related to the nature and mode of occurrence of silver carriers. Work was performed to determine discrete silver-bearing minerals and/or silver contained in solid solution in a suite of commonly occurring sulphides. Ore microscopy, SEM methods, Electron Microprobe and Ion Microprobe analyses were all used to answer these questions, and to find the silver carriers, so a metallurgical plan could be devised to improve silver recovery.INTRODUCTIONPotential economic exploitation of the Lady Loretta deposit in Queensland, Australia is driven by revenue derived from zinc and lead flotation concentrates and co-product silver recovery in lead. Relatively low recoveries of payable silver to lead concentrate, and high silver distribution to zinc concentrate necessitated an investigation into the natu"

Jan 1, 2002

By Monique Pharand, Jeet Basi, Simon Hille

"High quality activated carbon is essential in the recovery of gold in Carbon-in-Leach (CIL), Carbon-in-Pulp (CIP), and Carbon-in-Column (CIC) circuits. Goldcorp’s Campbell complex at Red Lake Gold Mines (RLGM) experienced a period of low soluble gold (Au) recoveries during Q3 2013, during which time the processing plant saw higher than typical Au grades in the CIP tails solution stream. A technical review identified that the CIP circuit may be experiencing a carbon-fouling issue. To further understand the degree of fouling, and to troubleshoot the low recovery problem, samples of carbon were collected from the CIP, elution, acid wash, and regeneration circuits, and submitted for characterization test work. This paper summarizes the steps taken to remedy the carbon-fouling problem at RLGM resulting in increased overall Au recovery.Overview of Red Lake Gold MinesRed Lake Gold Mines is located approximately 450 kilometres northeast of Winnipeg, Manitoba, in Ontario’s western boundary region.All mining is carried out through underground operations, utilizing overhand cut and fill, underhand cut and fill, and long-hole mining methods. Ore types include: silica-replaced carbonate veins with free milling gold, siliceous replacement-type mineralization (rich with arsenopyrite) marginal to veins, broad disseminated sulphide mineralization along major shears, and some minor sulphidized chemical sediment-hosted ore. The operation is supported by two milling complexes: Red Lake, and Campbell.Process DescriptionThe Campbell processing plant's main unit operations consist of grinding, gravity concentrating, flotation, autoclaving, leaching, carbon-in-pulp (CIP), carbon elution and reactivation, electro-winning, bullion smelting/refining and cyanide destruction, and concentrate handling. A schematic of the plant flowsheet is shown in the figure below.BackgroundHigh quality activated carbon is essential in the recovery of gold at many CIP/CIL/CIC processing plants. At RLGM, gold-bearing ore is milled and cyanide is added to leach the gold from the solids into solution. The dissolved gold then comes into contact with activated carbon, and adsorbs onto its highly porous surfaces. Gold is then recovered by separating the activated carbon from the main slurry for further refining. As such, the characteristics and quality of the activated carbon have a significant and direct impact on overall gold recovery."

Jan 1, 2016

By Jack Zhang, Chuck Edwards

"The versatility and specificity of rare earth elements (REEs) have led to their use in an ever increasing variety of applications in new technologies. Consequently, demand for REEs has increased significantly. However, to separate REEs safely and effectively is a complex and expensive process. While China has consistently invested in R&D of REE processing technologies, there have been only sporadic activities in REE mineral processing in North America in the past 20 years. This paper presents a review of REE mineral processing technology, providing an update on current capabilities in REE mineral processing. This paper reviews REE extraction from the major commercially valuable REE-bearing minerals such as bastnaesite, monazite, and xenotime, and also from the ion-absorption type of REE deposits. Currently, there are four major REE mining areas in China, one in the United Sates, and one in Australia. A review of the REE extraction processes in these major REE mining areas closes out the paper.INTRODUCTION The rare earth elements (REEs) include the 15 lanthanide elements, plus yttrium and scandium. The lanthanide elements are normally categorized in two groups: the light rare earth elements (LREEs), i.e. lanthanum through europium (atomic number (Z) = 57 through 63); and the heavy rare earth elements (HREEs), i.e. gadolinium through lutetium (Z = 64 through 71). Yttrium is usually grouped with the HREEs due to similarity in physical and chemical properties. Table 1 lists the REEs, atomic numbers, and abundances in earth’s crust (Taylor and McCleannan, 1985). Promethium is the rarest due to lack of stable isotopes. REEs with low atomic numbers are more abundant than those with high atomic numbers. More interesting is that the REEs with even atomic numbers are much more abundant than adjacent lanthanide elements with odd atomic numbers as shown in Table 1."

Jan 1, 2012

By Dominic Fragomeni

"The mineral processing industry has had a long history of innovation that is recognized but not often celebrated. These include significant advances in mineral measurement, testing, comminution, mineral separation and process control technologies that have transformed mineral assemblages into ore.This presentation presents some of the major mineral processing innovations and the impact they have had on our industry. As we look to the future, it is critical that we innovate and change. We will explore some examples of the next developments and how they can be catalyzed in the face of risk management, lower metal price cycles, resource constraints, inertia and the challenge of short term value delivery."

Jan 1, 2017

By D. B. Felsher

"Lakeshore Gold’s Bell Creek Mill is located in Timmins, Ontario. The mill has been in operation since 2009 and has undergone several small expansions since then. In 2012 - 2013 the first major mill expansion was commissioned raising the mill capacity from 2,000tpd to 3,150tpd. This was done through the installation of a new ROM ore truck dumping facility, jaw crusher, ore storage dome, SAG mill, leach tank, CIL tank, and electrowinning cell. This paper will cover the equipment installed to raise the tonnage as well as the commissioning of the new equipment including problems encountered and how these problems were solved.IntroductionLake Shore Gold acquired the Bell Creek Mill, along with the Bell Creek Mine, from the Porcupine Gold Mines Joint Venture, a joint venture between Goldcorp Canada Ltd. and Kinross Gold Corporation, in December 2007.The Bell Creek mill, which processed ore from the Bell Creek Mine has consistently achieved recoveries of over 95%, is a conventional gold mill circuit, involving crushing and two stage ball mill grinding, gravity and leaching, followed by Carbon-In-Pulp (CIP) process for gold recovery. The facility had been placed on care and maintenance in 2002. At the beginning of 2009, the mill had been refurbished with an initial capacity of 800 tonnes per day and was subsequently refurbished to a capacity of 1,500 tonnes per day near the end of the third quarter of that year. The Mill was then expanded in 2010 to a capacity of 2,000 tonnes per day.In late 2011, the Company commenced a 50% expansion of its milling facility, from a processing capacity of 2,000 tonnes per day to 3,150 tonnes per day. Phase 1 of the expansion, which mainly involved enhancements to the solution circuit (“back end”) and increased the mill’s capacity to 2,500 tonnes per day, was completed at the end of 2012. Commissioning of Phase 2 of the expansion, to a capacity of 3,150 tonnes per day, commenced at the end of July 2013."

Jan 1, 2015

By Yaw Boadi, Andrew McCallum, Sandy Gray, Yavuz Atasoy, Peter Wemyss

"Various full-scale test programs and installations of the InLine Pressure Jig (IPJ) have provided evidence that pre-concentration of the difficult to leach sulphide mineral through gravity can provide significant increases in economic recoveries. The continuous gravity concentrates are intensively treated either by re-grinding or Intensive Cyanidation. Data from various mine sites worldwide is presented. Treatment of complex ore bodies with this low cost methodology may render previously uneconomic ore bodies financially viable and assist in the recovery profile of transitional ore.INTRODUCTIONThe use of gravity is made extremely attractive in complex ore situations due to the low cost of operation, typically a few cents per ton operating cost and lack of chemicals.Gold mines which suffer from poor recovery due to complex mineralogy such as Stibnite, Arsenic, Carbon, Telluride, Silver and other pacifying agents such as Iron, which can form coatings, can all benefit from the process proposed in this paper. The key issue is not overall recovery as much as one of economic recovery. The key to this is maximised recovery at the lowest possible capital and operating cost. Other options such as flotation are reviewed but are not seen in many instances to be the panacea due to issues discussed in the paper. The use of the InLine Pressure Jig in the re-circulating load of the milling circuit is a cost effective means of recovering a sulphide/gold concentrate containing the complex mineral assemblages which require re-grinding and intensive leaching for optimised gold recovery.The benefits of Jig Assisted Grinding (JAG) are many and the challenge over the past years has been developing, understanding, implementing and evaluating the benefits of various flowsheet models. This has involved the reconciliation of results in plant scale trials back to the original laboratory test program. The following paper outlines the insights gained in this area through extensive work carried out by many people across both laboratories and plant sites in Australia and overseas. The examples in this paper are some of the work carried out on a few selected sites but similar work has been carried out on other sites such as Penjom, Granny Smith and Agnew. This work has eventuated in several installations which we believe have great importance in the future of the gold processing industry. They will lead the way forward to the modern all-gravity plants of the future.Compared to flotation, for the recovery of sulphides, gravity is a simple option. The simplicity generally translates to low capital and operating cost."

Jan 1, 2004

By Jim Wickens, Andy Cole, John Pekrul

"The roaster facility at Barrick Goldstrike Mine treats double-refractory sulfidic/carbonaceous gold ore. Prior to oxidation in the roasters, the ore is ground in two parallel dry grinding circuits utilizing 19’ Ø x 75’ double rotator mills. The design plant throughput was 12,000 dstpd. However, process improvements have significantly increased throughput rates by 25-50%. The current daily throughput record is 20,078 dstpd. Grinding circuit improvements contributing to this success include feed size reduction, ball size optimization, automatic ball charging optimization, and operating strategy changes. In addition to the changes already made, this paper discusses future optimization initiatives including on-stream particle size analysis and “real-time” ore hardness determination techniques.INTRODUCTIONBarrick Goldstrike Mines is located 29 miles Northeast of Carlin, Nevada, USA. Through 2001, the property has produced over 23 million ounces of gold making it one of the premier gold operations in the world.Prior to Barrick’s ownership, the property began producing gold from a small heap leach operation in 1975. The small-scale heap leach production continued through 1986, and in January 1987, Barrick acquired the property. Increased exploration activity by Barrick significantly increased gold reserves. In August 1988, a 4,500 dstpd mill facility was commissioned to treat high grade oxide ore. Also, heap leach operations had significantly expanded. In 1990, the mill was expanded to 6,000 dstpd, and the first autoclave was commissioned to treat refractory sulfide ore. By the end of 1996, the mill and pressure oxidation facility had expanded to 16,000 dstpd and heap leaching had ceased as oxide reserves were exhausted. In 2000, a roaster facility was commissioned to treat double-refractory sulfidic/carbonaceous ore."

Jan 1, 2003

By J. A. Finch

"A method of sampling and presenting bubbles for imaging for use in full-size flotation cells is described. The device (bubble viewer) comprises a tube attached to a sealed glass viewing chamber. The assembly is first filled with frother-containing water (to prevent coalescence) and the tube immersed at the desired location below the froth. For a few minutes bubbles are collected in the viewer free from slurry and are readily imaged. To reduce bubble overlap and the problem of defining the plane of view, the viewing chamber has a sloped side. Bubbles rise, encounter this slope, spread into a single plane and slide up. This simple expedient virtually eliminates overlap and provides an unambiguous focus plane - the underside of the sloped glass. The bubble image is captured and processed to give size data. The bubble viewer has been employed at several concentrators on different types of flotation cells. Examples of the images are given. The impact of position in the cell and the effect of changing gas rate on bubble size are illustrated. This technique provides a sensitive measure of the effects of process variables on bubble size.INTRODUCTIONDespite the extensive use of flotation in the mineral processing industry, the methodology employed for cell design is largely based on empirical rules rather than on first principles. One of the main reasons for this state of affairs is that the local flow structures encountered in industrial-scale machines are very complex. These flow structures are difficult to simulate under the controlled conditions of the laboratory and the difficulty to solve the mathematical models that treat the randomness of such flows also mean theoretical treatment is limited. Understanding flotation cell hydrodynamics requires reliable data, which involves the implementation of measurement techniques capable of performing both at the laboratory- and the industrial-scale, In addition, it is desirable that such techniques are amenable to automation to reduce extensive manual intervention in the data collection process."

Jan 1, 2002

By John Frostiak

"Kahama Mining Corporation Limited, a wholly owned subsidiary of Barrick Gold Corporation, poured the first dore bar and filtered the first concentrate produced at the Bulyanhulu mine on February 28, 2001. This event marked the completion of the initial development of the Bulyanhulu Mine – Barrick’s first mine located outside of the Americas.Bulyanhulu is a 2,500 tpd underground mine located in the Lake Victoria gold belt of northern Tanzania. Gold is recovered as a gravity concentrate and smelted on site to produce dore bars or collected in copper concentrate that is shipped to offshore smelters. The facilities were constructed to meet Canadian standards. Unit operations include single stage crushing, SAG milling, gravity recovery, flotation, thickening and dewatering. Tailings are converted to paste and returned underground as paste backfill or pumped to the surface tailing site. The surface paste tailing disposal system is believed to be first of its kind in the gold industry. Paste disposal has several advantages over slurry, including lower dam construction costs, reduced water losses, and lower reclamation costs. This paper describes the facilities and discusses the challenges faced during development and construction including logistics, lack of infrastructure, recruiting and training, security, and social issues as well as initial operating results.INTRODUCTIONBarrick Gold Corporation completed the Bulyanhulu mine development in 2001. Capital cost of the project was US$280 million. The mine produced 241,575 ounces from start of milling to year end at a total cash cost of $197 per ounce. Numerous challenges were overcome in the mine’s development due to the general lack of infrastructure in Tanzania and the mine’s location some 1200 km inland by road from the port of Dar es Salaam."

Jan 1, 2003

By Michael B. Cortie

Mesoporous gold sponge has the unique property of being both metallic and highly resistant to oxidation. It has potential application in catalysis, in bio-sensors, in optical coatings, in analytical chemistry and, as we show here, as the basis for a new kind of ultra-capacitor. Due to the cost of gold, the most probable niche for a gold-based ultra-capacitor would be in the high-power/high-energy regime, a region where gold would compete with devices based on RuO2. A high internal resistance limits the power that can be usefully drawn from existing carbon-based ultra-capacitors, and that this problem can potentially be overcome by gold-based devices. A simple proof-of-concept ultra-capacitor based on mesoporous gold is described and its behaviour during charge and discharge cycles examined. In this work a step change in the input or output voltage of the device was used as the controlling parameter. There was also a residual faradaic current resulting from traces of undissolved aluminium left over from the AuAl2 precursor used to make the sponge, and some charge storage due to polarization of the solution. Deconvolution of these three effects was not entirely accomplished, but an ostensible capacitance of about 7 to 14 mF/g Au was demonstrated. Further improvement from these early results seems likely.

Oct 1, 2003

By Mark Ferra

Flotation is used in mining to produce concentrates of copper, gold and several other valuable ores. In 2017, a copper mine near Globe, Arizona improved their rougher cells productivity using technically advanced electro-hydraulic actuators in the flotation process by enabling excellent tank pulp level process stability. The new actuators controlled the dart valve position to allow pulp to leave the cell. Tank cell pulp level can change due to feed and discharge fluctuations from neighboring tanks. When traditional pneumatic actuators are used, they have sluggish response times and overshoot due to the inherent physical property of air being compressible. Electro-hydraulic actuators have the benefit of hydraulic stiffness to deliver accurate and repeatable (0.1%) dart valve positioning. The froth layer has more opportunity time to maximize mass transfer into the launderer. The results are an increase in copper recovery by 2-4%. INTRODUCTION In 2013 there was an international flotation technical conference well attended by respected flotation specialists for both mining companies and academia. During the technical session a leading metallurgist was discussing pulp level measurement and said that when he was on the cell deck he stated, pneumatic actuators air cylinders stroking up and down. The presenter then claimed with confidence that "I listened to actuator move so the pulp level in the tank was being controlled!" No one questioned his assumption and I can assert that the audience was quite technical and not shy in their critiques of speakers. The flotation community simply believed that the existing pneumatic technology was enough with no alternative. Having a stable flotation cell pulp level is critical to effective copper recovery. Controlling pulp levels in flotation cells is a complex task that includes modulating dart valves in each cell. The use of REXA Electraulic actuators will decrease the process dead time and maintain froth height in a controlled manner, especially from pulp slurry volume fluctuations from neighboring cells. By reducing flotation cell pulp level tank height variation, a copper mine in Arizona has realized a 2-4% recovery improvement by increasing the froth transfer to the launderers in the rougher cell circuits compared to pneumatic actuators. This paper examines the benefits of using an electro-hydraulic actuator to ensure proper pulp level control and reduce the process operational cost. It will focus on actuator positioning the dart valves to maintain pulp level setpoint at a copper mine in Arizona.

Jan 1, 2019

By David R. Macedon

"Through the years, a wide variety of dust control methods have been utilized at mineral processing operations. While some have been successful, many have been highly ineffective. Dust Control systems currently in use include baghouse systems, fog systems, surfactant spray systems, and foam dust suppression. While baghouse systems can be effective, they are capitalintensive and costly to operate and maintain. Chemical dust control programs can be very effective. However, if applied incorrectly, they can have detrimental effect on mineral recovery. Thus, many operations utilize a combination of baghouses and water, often with limited success.Recent advancements in surfactant and polymer chemistry have resulted in substantially improved chemical dust suppression programs. These products range from non-corrosive surfactant/humectant combinations for road dust control to foam-based systems for crushers and transfer points, to advanced polymers for pile binding and soil stabilization. These advances are discussed in detail, citing results from fieldwork in the precious and base metals industries.INTRODUCTIONThe global nature of the mineral processing industry presents a unique set of challenges. Traditional thinking would tell us what works in one place should work in another. This could not be further from the truth in the area of dust control. We learn very quickly that there are a number of factors that can affect the efficiency and success of a dust control program and that these factors are not all chemical or equipment related. Some of these factors include facility maintenance, product selection, water quality and characteristics, and economic considerations.What has been learned from past experience is that each mineral processing plant presents a unique set of factors that will affect the ability to create an optimal dust control program. This paper presents a myriad of treatment options that will highlight the advancements in chemical dust suppression products and equipment."

Jan 1, 2004

By Joe Pease

"The demand for minerals and metals is increasing. Head grades of ore bodies are dropping. Remaining ores are becoming finer grained, more complex, and more logistically challenging. Mineral processing – in particular comminution – already consumes a huge amount of energy. But in 20 years’ time, it will require about six times as much energy as today to meet the world’s mineral demand.Unless we do something different.As minerals professionals, it is our job to find that “something different”. The world is relying on us. Of course, we must look for new breakthrough technologies and techniques. We must find them, and we will find them – most likely in surprising areas.But what if we also already know how to make 30-50% improvements to efficiency? Just by using existing technologies, by applying modern analytical techniques, by custom designing our plants, by applying manufacturing principles, by breaking down our management silos between disciplines.The thing is, industry professionals already know this. Yet – in spite of a lot of intelligent people trying very hard – we just can’t seem to make it happen.This discussion considers why, despite our best efforts, we don’t get the best out of what we already have. Why we are wasting energy and money. Once we understand why, we can set about unlocking that value and improving industry productivity and energy efficiency. We will discuss the role that professionals and volunteer professional organisations like CMP and CEEC can play in catalysing the changes."

Jan 1, 2015