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By J. Gillies

"Those of you who were at last years C.M.P. meeting are aware there was discussion at that meeting concerning the best method of assisting the assayers of metal mines to exchange new ideas and methods of assaying. The opportunity to advise you of what came of that discussion is very much appreciated.There are several societies, including the Chemical Institute of Canada, the Spectroscopy Society and others that could be of some assistance to assayers. However, since these societies cover a rather broad field and not many mine assayers have the opportunity to attend their meetings, it was felt that an organization oriented to the specific needs of the mine assayers would be of more value to them.Several years ago an attempt was made to hold meetings for the benefit of assayers in conjunction with the Conference of Metallurgists held each year by the Metallurgical Society of the C .I.M.M. This did not work because very few of the mine assayers attended the meetings.With the very evident success of the type of meetings the C.M.P. have and the excellent groundwork done by your secretary, Mr. Stevens, in talking about this to mine management and assayers at many mines across the country, it was decided to hold a meeting at Noranda on October 8 to discuss how best we could help ourselves solve our problems.For the initial meeting it was felt that perhaps it would be better to start with a smaller group, so invitations were sent to mines in Ontario and Quebec that were geographically fairly close to Noranda."

Jan 1, 1970

By J. H. Pateson, D. C. Comrie, D. J. Ritcey

"Geopolymers are inorganic semi-amorphous three dimensional silico-aluminates of the poly(sialate) type (-Si-O-Al-0-) or of the poly(sialate-siloxo) type (-Si-O-Al-O-Si-0-). Polycondensation occurs at low temperatures with geopolymers being stable up to 12oo0 c. Research, development and application technology pertaining to geopolymers is being undertaken jointly with Dr. Joseph Davidovits of The Institute for Applied Archaeological Sciences of Florida, U.S.A. This joint focused upon the chemical Barry University in Miami Shores, research and development program has stabilization and solidification of various waste products through geopolymerization. Of particular interest is the geopolymerization of mine wastes including tailings and waste rock derived from the processing of base metals, precious metals, potash, coal and uranium deposits.INTRODUCTIOND. Comrie Consulting Ltd., in cooperation and technical liaison with CANMET, Ottawa has been testing the application of geopolymers to mining wastes. Corporate efforts to date have concentrated upon reactive acid tailings, principally from the abandoned Kam-Kotia Mine site, and dewatered paint waste sludges. Test work conducted to date has successfully yielded geopolymer treated materials and wastes with increased chemical and structural stability. Wastes containing heavy metals, cyanides, arsenic and sulphur dioxide have been successfully geopolymerized."

Jan 1, 1988

By B. Loveday, G. W. Delaney, S. Cummins

"Applying DEM to prediction of tumbling mill performance is challenging because several different modes of breakage are active in the process. As our knowledge of breakage and computational capacity improve, it is worth revisiting previous simulation tasks which did not produce a satisfactorily realistic description of a measured process. At SAG 2006, we reported the simulated and measured outcomes of treating a well characterised ore in a 1.2 m diameter mill. This well instrumented, pilot scale mill at the University of KwaZulu-Natal has been combined with some new approaches to ore testing to allow different modes of breakage to be tested. The mill design allows the rate of generation of fine material to be measured in close to real time for autogenous and SAG mill charges. The updated simulation model estimates mass loss with particle evolution and embeds the cumulative damage and breakage.The simulated results are compared with the measured results. Issues such as relating modelling inputs to particle breakage characterisation data and the accuracy of the predictions of the models are discussed."

Jan 1, 2012

By Simon C. Dominy, Alwyn E. Annels, Mark A. Noppé

Abstract - Mineral Resources and their subsequent conversion to Ore Reserves are of key importance to mining companies. Their reliable estimation is critical to both the confidence in a feasibility study, and also to the day-to-day operation of a mine. Together with sampling, assaying, geological and other errors introduced during interpretation and estimation, additional errors are likely to be introduced during the application of technical and economic parameters used for conversion of resources to reserves. There is thus a requirement for high-quality interpretation and estimation to be supported by high-quality data. Any company expecting to make sound investment or operational decisions must base this on both relevant and reliable information. An Ore Reserve statement generally contains a single set of grade and tonnage figures without a discussion of the potential inherent errors in these estimates. Some sensitivity studies may be run, but confidence limits are rarely quoted and, if they are, often do not take into account many of the factors that cause uncertainty in the grade and tonnage estimates. Mineral Resource and Ore Reserve estimates thus carry certain errors leading to uncertainty and risk; some of these are unquantifiable for various reasons, for which the operator should be aware. This paper presents a review of the potential sources of error that might occur during a resource estimation program, which are carried through into the reserve estimate. A number of methods are discussed that allow the estimator to be more transparent about the inherent risks in his/her estimate. Emphasis is placed on data quality, and the requirement for strong quality management to be linked to continuous improvement.

Jan 1, 2002

By R. W. Nice

"For many decades the incidence of a highly active graphite-like ore has plagued the McIntyre mine. This ore acts as a precipitant of the gold complex immediately upon formation of this complex. The gold is subsequently discharged with the tailings.Many different methods have been devised by various researchers all of which proved inapplicable for the McIntyre problem.Recently, McIntyre personnel, through their own research, developed a flowsheet. This circuit should give an overall recovery of 36% which is below the 94% experienced in the mill at present. Therefore, less revenue would arise from treatment of these ores. On the other hand there exists a possibility of more efficient mining methods in some of this ore thus allowing more economic recovery.INTRODUCTION This paper has been prepared to serve two purposes:i) To propose a method of recoverying gold from a sizeable orebody at the McIntyre mine at Schumacher.ii) To summarize and present the many methods suggested to solve a very old but very real mineral dressing problem familiar to the industry as long as cyanidation itself."

Jan 1, 1971

By A. Chaisantikulwat

Most solid-oxide fuel cell (SOFC) modeling emphasizes steady state cell operation. However, understanding the dynamic behavior is essential to predict the performance and limitations of SOFC power systems. In this work, we demonstrate a dynamic model of a SOFC, and we simulate a feedback control scheme that can maintain output voltage despite load changes. Dynamic response is determined as the solution of coupled partial differential equations derived from conservation laws for energy, mass and electric charge. From such a model, the step responses to system input variables can be determined. Low order dynamic models that are sufficient for feedback control design can be derived from the step responses. The development of the partial differential equation model is outlined, and the limitations of the control system are discussed.

Jan 1, 2005

By R. J. Chase, C. Davies

"The Merelani graphite-tanzanite deposit is located in northeast Tanzania, 14 kilometers south of Kilimajaro International Airport and in close proximity to the towns of Moshi and Arusha. The graphite mineralization is hosted by relatively undeformed linear Proterozoic metasedimentary gneisses, several of which have been subjected to hydrothermal alteration resulting in tanzanite mineralization. Exploration work comprised detailed geological mapping coupled with pit and trench channel sampling and a subsequent 1500 meters of diamond drilling. In addition, metallurgical tests have shown the graphite to be of unusually coarse flake size, crystallinity and high purity.Feasability studies have shown the economic viability of a major coarse flake graphite deposit with the measured resource to 50 meters in excess of 9 million tonnes assaying over 85 graphitic carbon. Production is due to start by the end of the first quarter of 1994 with the processing plant design capacity initially set at 15 000 tonnes per annum.In addition to graphite production, tanzanite will be produced through selective mining within the graphite open pit in the upper horizon and from underground workings within the lower horizon.The Merelani graphite-tanzanite deposit will be the first major orebody to be exploited through means of private funding since Tanzania gained independence"

Jan 1, 1994

By Jerry Z. Lu

Belt conveyor design involves the evaluation of belt tensions, drive selection, pulley configuration and other technical issues. The conveyor belt tensions vary with conveyor layout, drive pulley configuration, belt selection, and idler selection. The decisions for the belt conveyor construction always take all technical, commercial and maintenance issues into consideration. A good conveyor design shall provide required operational features and at the same time be cost effective. The common issues for an engineer to face during belt conveyor design include: (1) Conveyor drive selection ? drive with fluid couplings or variable frequency drives; (2) Drive system configurations - single pulley large drives or dual pulley smaller drives, if intermediate tripper booster drives shall be applied, what power ratio should be adopted for a multi-drive conveyor; (3) Gear reducers ? shaft mount drives, right angle gear reducers or parallel gear reducers; (4) Drive pulley lagging - ceramic lagging or rubber lagging; If ceramic lagging, what type should be used. (5) Conveyor speed variation ? If conveyors run at variable speeds, faster speed/lower percentage loading or slower speed/higher percentage loading. In many cases the decision maker find themselves in a dilemma ? technical benefits vs. financial benefits, capital cost vs. operational cost, and capital and operational cost vs. maintenance effort. Although many conveyor design topics above have been discussed in numerous technical papers and design reference books, management executives and inexperienced engineers may be confused and feel lost. The consultation of people around them may lead to different opinions since experiences tend to vary, making the decision making process complicated. The purpose of this paper is to simplify these complicated issues and provide useful guidelines for belt conveyor design. This paper focuses more on providing simple and practical answers and solutions instead of discussing each topic academically and theoretically in depth.

Nov 1, 2011

By M. Falutsu

"The PSI-200 is a rugged, innovative, and easy to install on-stream size analyzer. Its calibration is simple and can be done on-line, during operation. Two measurements are displayed on the panel, which are expressed as percent passing a selected size, or as any statistical diameter. These two measurements are given as two continuous 4-20 mA output signals. Operation alarms are displayed on the screen or are given as digital output signals.The PSI-200 has been used in various applications at Lakefield Research. Particle sizes ranging from 10 µm to 450 µm have been monitored successfully, with an accuracy of 1- 2%. Having the size measured continuously and reliably, optimum conditions have been established for the grinding circuit, resulting in a superior quality in pilot plant testing.INTRODUCTIONThe challenge of any operating plant is to optimize product quality, maximize throughput and minimize operating costs. The importance of particle size measurement at a grinding circuit is well recognized. Monitoring continuously the particle size and keeping the product as uniform as possible is crucial to the whole mill operation regardless of the nature of the operation.Various techniques and instruments have been developed over the years attempting to give reliable on-line size analysis data. The operating difficulties and the reliability of these equipment still present major drawbacks and none of them proved to be widely accepted.PSI-200 is a relatively new on-line analyzer. The operation is simple and of low cost and the maintenance required minimal. It measures particle size and it displays two parameters of the solids size distribution, either weight fraction of passing a certain size or any statistical diameter. Two analog outputs can be sent to a process control system and through a supervisory control loop the correct action can be taken to maintain the desired particle size (perhaps adjust the feed rate to the grinding mill)."

Jan 1, 1993

By G. Gagnon

"HistoryMining of the Schefferville iron deposits began in 1954 on completion of the 357 mile railway linking the mines and the St-Lawrence river port of Sept-Iles. Apart from crushing, no treatment of these ores was required before smelting. In the late 1950's, testwork began at schefferville to develop a process for upgrading the extensive lower grade deposits containing 51% iron with 15% silica (natural analysis). Engineering for a six million ton per year beneficiation plant using cationic silica flotation and the A-C grate kiln Began in 1970 and the first pellets were produced in mid-1973.Production requirements and operating difficulties have restricted capacity to approximately 85% of design but on going improvements are being made continuously to attain design capacity.GeologyThe sedimentary ore bodies of the labrador trough occur in a belt 5 to 10 miles wide and 60 miles long and contain 51 individual deposits varying in size from 1 and 60 million tons. The ores are classified into three main color groups."

Jan 1, 1981

By Paul Delottinville, Maynard Hall, Henry Hillier

"An expert system application for supervisory control and optimization of the indurating process at the Iron Ore Company of Canada (IOCC) has been developed and installed in closed-loop. Prior to the installation of the expert system, the indurating machine was rebuilt and the instrumentation revamped. A Foxboro I/A Distributed Control System (DCS) was installed for regulatory control, and a new control strategy configured. The modernization of the regulatory control has resulted in significant improvement in both production rate and product quality. Expert system control was implemented in September 1996. Preliminary indications are that the expert system has further improved the consistency of product quality, enhanced fuel efficiency and increased productivity. The expert system considers both wet and dry sections of the circuit, and its optimization scheme is driven by pellet tumble index and compression strength. Statistical Process Control (SPC) rules were implemented in the expert system as part of the quality analysis and control scheme. The expert system application was developed and delivered using the Comdale Expert Optimizer (CEO), and has been in continuous closed-loop control since its installation. The system development and implementation is described, and preliminary benefits are presented..... IntroductionIn early 1996 the Iron Ore Company of Canada (IOCC) contracted Comdale Technologies of Toronto to develop and implement a real-time expert system for optimizing the indurating pelletizing furnace at our plant location in Labrador City, Newfoundland.The decision to install the expert system has been timely. Like many other resource-based industries in increasingly competitive markets, IOCC recognizes the need to find ways to improve the efficiency of our production process and ensure that product quality is maintained at the highest levels. With the Labrador City plant producing 11 million tons of iron ore pellets annually, implementing the best technology solutions to meet these objectives is critical."

Jan 1, 1998

By Andrew Kerr

Abstract - The base-metal and PGE contents of samples from magmatic sulfide mineralization are commonly correlated with their sulfide contents, indicating that the metal contents of bulk sulfides remain approximately constant within a given prospect or part thereof. Calculated sulfide metal contents provide valuable information in mineral exploration and research, but there are few formal descriptions and analyses of the procedures. Sulfide metal contents are best calculated using an assumed value (35.7% S) for a typical pyrrhotite-chalcopyrite-pentlandite mixture, and there appears to be little advantage in accounting for sulfide species separately. Regression of metal data against sulfur is probably the most rigorous approach, but is not always practical. Above 10% S, calculations are very robust, but lower sulfide contents generally demand at least some correction for non-sulfidehosted metals. Such corrections can become significant below 5% S, and/or in olivine-rich samples. They are best accomplished by mass-balance calculations, using concentration data from unmineralized host rocks. Significant uncertainties are introduced by analytical errors for sulfur, base-metals, and PGE, which are commonly measured from separate sample aliquots. These combined errors in sulfide metal contents generally exceed ±10%, but expand further at low S contents. In general, treatment of data from samples containing <2.5% S must be approached with caution, especially for PGE, for which the exact host minerals may not be known. Application of the method in simple grade-potential assessment is straightforward, but research studies involving sulfide-poor samples are inherently more complex. Under-correction or over-correction of data for non-sulfide-hosted metals can lead to false negative or positive correlations between sulfide metal contents and sulfide content. As the latter may itself be linked to geological parameters, such as depth within an intrusive body, undue significance could be ascribed to such trends. There are also valid geological reasons for such correlations, and such data require careful assessment to separate true and artificial variations. Propagated analytical uncertainties increase significantly in sulfide-poor samples, and must also be borne in mind whenever data from different localities or units are compared and contrasted.

Jan 1, 2001

By J. Gao

We present results from our investigation of the concept and practice of using surface-charged latex nanoparticles as building blocks for conductive membranes. Nanoparticles were synthesized by free-radical co-polymerization of two hydrophobic monomers, butyl acrylate (BA) and methyl methacrylate (MMA), a crosslinker, N, N&apos;- methylenebisacrylamide (BIS), and a charged monomer, sulfonate styrene sodium salt (NaSS), in water. The resultant nanospheres were characterized with static and dynamic laser light scattering. Thin films were cast from concentrated particle dispersions, followed by incubation at ?110 °C. Conductivity, water uptake and final charge content were measured. The membranes have higher conductivities than both amorphous films cast from sulfonated BA-MMA-Styrene copolymer chains and BA-BIS-MMA-NaSS gel films. TEM images and neutron scattering spectra confirm the particulate structure of the membranes.

Jan 1, 2005

By Mike D. Riley, Alan V. Bell, Ernest K. Yanful

Acid mine drainage (AMD) research under the MEND program has been ongoing since 1988 at the Heath Steele Mines waste rock piles including sulphide material, outside Newcastle, NB. In 1989 approximately 10,000 mt of waste rock was placed on a prepared sand base with an underlying impermeable membrane. The waste rock pile was heavily instrumented for measuring oxygen concentrations and temperatures. In September 1991, a composite soil cover designed for the Heath Steele climatic conditions, using local soils, was placed over the pile, creating a totally enclosed system. Moisture content and oxygen probes were installed within the composite soil cover to monitor changes within the soils over time, while two large-size lysimeters were installed below the cover to monitor the hydraulic conductivity of the cover. The waste rock site has been monitored on a monthly basis since installation of the cover, for performance of both cover and waste rock. The monitoring shows very clearly that the placement of the composite soil cover has had a major impact on the generation of AMD. Major reductions in temperature and oxygen concentrations within the waste rock pile indicate that the cover has significantly inhibited the oxidation reaction that generates the AMD. Performance data have shown that the cover has maintained its integrity under the climatic conditions of the area.

Jan 1, 1995

By Bing Li, Kai Liu, Yongcheng. Zhao

With the ongoing development of copper smelting technology, the improvement of environmental emission control and achieving an automated continuous copper pyrometallurgical process have become the key development goals for copper smelting. The double bottom blowing continuous copper smelting process combine bottom blowing smelting (SKS) and bottom blowing converting (BCC) process and fire refining as “three-connected furnaces” arrangement is a pyrometallurgical process independently developed by China’s ENFI which can continuously produce copper from raw material through to anodes. This technology can improve energy efficiency and reduce environmental emissions for the overall copper smelting and converting process. This paper discusses the engineering characteristics and production practice of the SDIC Jincheng Metallurgical Project, which operates SKS smelting and BCC converting process with “three-connected furnace” arrangement for the first time in the world. Advanced engineering concepts and tools were used to optimize the configuration during the project engineering stage. The operation shows that the process has good environmental performance, reduced energy consumption and high level of automation, which is a new choice for copper continuous smelting process. INTRODUCTION One of the most important developing trends for the overall copper smelting process is to develop a continuous operation. Continuous copper smelting can maximise energy efficiency in copper concentrate and make full use of the rich heat treatment system. Cold charge and a part of low-heat-generating materials, which are processing with additional equipment in traditional copper smelting process, can be processed with rich reaction heat in continuous copper smelting and converting process to achieve good economic benefits. Yuan and Wang (2017) noted that SKS+BCC copper smelting process can reduce the secondary SO2 emissions compared with discontinuous copper smelting process, which required transportation of melted matte by matte ladle and may cause secondary pollution. The continuous copper smelting process can also reduce the generation of intermediate cold materials.

Jan 1, 2019

By Ayako Iwakoshi

Highly concentrated pastes of gold nanoparticles were successfully produced by use of a special kind of protective polymer and a mild reductant. Solid part of the pastes consists of up to 85wt% of gold nanoparticles, 10~30 nm in diameter, and residual protective polymer. This component can be diluted by any kinds of solvent at arbitrary rates. Electronics, optics, catalysts, colorants and surface metal coatings are possible application fields. 1. Introduction Noble metal nanoparticles are of interest in a variety of fields ? such as colorants, metal coatings, electronics(1), optics(2), and chemical catalysis(3). Especially, in the color field, the gold nanoparticle has been known as an aesthetic red colorant for stained glass and fine glassware, such as Venetian glass. The mechanism of coloring is attributed to surface plasmon absorption of gold nanoparticles(4,5). The gold nanoparticle in stained glass shows very clear red color, which is very durable for hundreds years. On the other hand, the red color of organic pigment in paint films often fades away within several years. We intended to reproduce the elegant and stable coloring of stained glass in paint films. In order to color a very thin, 20~50?m, paint film like stained glass, production of highly concentrated dispersion of gold nanoparticle is necessary. To achieve this, there were two issues to be overcome. One is how to prevent the coagulation of gold nanoparticles in highly concentrated solution. So far, several methods to prepare gold nanoparticles(6,7) were reported. But only a few methods succeeded to stabilize the gold nanoparticle dispersion at higher concentration than ppm order. The other is controlling of the particle size, this is because the color of gold nanoparticles is very sensitive to the particle size. Only when the particle size lies around 10 nm, the suspension exhibits red color like stained glass.

Oct 1, 2003

By M. Xiao Bo

In recent years, there has been a heightened interest in the hydrometallurgical processing of sulfide ores and concentrates (especially copper sulfide ores and concentrates) mostly in the USA and Chile. Currently, hydrometallurgical operations account for about 30% of the primary copper production. In the present research, the leaching phenomena of IOCG (iron-oxide hosted copper-gold) ores and concentrates were studied. The IOCG ore, which is characterized as having a predominant amount of magnetite with fine chalcopyrite, is currently the center of attention for new copper resources. Heap leaching of IOCG ore is desirable because of its low cost. However, the leaching characteristics of the ores and concentrates and the mechanisms of copper leaching require investigation. This study defines the factors, which affect the leaching operation, such as the ORP, pH and oxidizing agents. Based on these results, the optimal leaching conditions are provided for pilot column leaching test and ultimately, commercial operations.

Jan 1, 2007

By John F. Vynne

This paper will discuss several of the systems and processes that have been developed over the past few years, and are now being utilized by major mining companies on draglines in North America, Australia and South Africa. These technologies include production monitors and reporting systems, GPS navigation systems, structural integrity monitoring systems, structural analysis studies to increase the dragline RSLs, and inspection and response strategies. The use of these technologies provides significant increases in dragline production, and reduces maintenance costs and downtime. The question that needs to be asked is what value is there in monitoring? Increasing dragline productivity is dependent upon to two items with the overall goal being to maximize the number of bank cubic meters moved and to uncover more coal: 1) maximizing payload and 2) maximizing the number of cycles. If you do not measure and try to optimize the parameters that impact payload and number of cycles, there is very little chance that you can improve overall dragline productivity. These parameters are: Maximizing payload is dependent upon the following: ? Geology ? Blasting ? Monitor weighing accuracy ? Engage location ? Disengage Location ? Rigging ? Suspended load ? Bucket characteristics ? Operator skills ? Minimizing rehandle Maximizing the number of cycles depends upon maximizing digging time, and minimizing cycle and delay/down times by: ? Minimizing Operational Delays ? Minimizing Mechanical Delays ? Minimizing Idle time ? Minimizing Walking time ? Minimizing Fill Time ? Minimizing Swing Angle ? Maximizing Swing & Return Rates ? Minimizing Spot Time A third reason to monitor, conduct structural analysis studies, and have inspection strategies is to prevent catastrophic failures such as shown in the following photographs (figures 1 & 2).

May 1, 2008

By Christoph Mueller

?Globalization and the impact on mine operations? is one of the themes of the 2003 annual CIM meeting. Global mining business in practice always means to act with local base material resources in order to reach the mining company?s global business goals. On the other hand these operations are characterized by cost pressure and cycling product prices. Driven by actual prices, local product markets and local production cost, one time one mine can be most efficient while under different circumstances another mine will be the most efficient producer for the same customer [PENSWICK, 2001]. Therefor in the future the most profitable mining companies will be those who have permanent ?real-time? control on their actual production cost level. Certain approaches are under way to provide reliable modeling tools for aiding mining companies in highly complex decision finding procedures. A high potential for enhancing efficiency is the integration of all single steps of the mining working chain into a production process structure to make advantage of an optimized flow of material and information through the ?moving ore factory? [WIGDÉN, 2001]. Crucial to all these activities is the ability of getting reliable, just-in-time information from the entire mining production chain. As modern mining machinery today is controlled electronically and even already operated autonomously, the theoretical preconditions for the data acquisition is already fulfilled. But up to now, there was no way of cost effectively exchanging the process information with databases, simulation tools and other enterprise level software. Any data exchange problem had to be solved by individual and expensive software development projects. To solve these problems, the International Rock Excavation Data Exchange Standard (IREDES) was launched in 2000 by major players in the industry. The task of this initiative is to define a ?common electronic language? for easy and standardized data exchange between mining machines and central computer systems. As in other industries, this standard is expected to have significant impact on the use of automated equipment. It shall provide easy ways of using multi vendor machine installations in data controlled mining processes. At the same time it reduces cost for individual development of interfaces for all parties involved. The standard?s technical architecture is flexible and open - also for future applications. It uses modern technology enabling easy data exchange with commercial databases as well as open on line networking.

May 1, 2003

By G. A. Sutton

This paper, describes a case example from San Manuel mine, where in situ copper leaching of the supergene zone was done over a 14 year period (1986–1999) in conjunction with underground and open-pit mining operations of a copper porphyry deposit. In 1993–1994, testing of well fields was done to determine the amount of copper that would be recovered from in situ leaching of the supergene zone, which was composed primarily of chrysocolla and copper-clay minerals. It was determined that the leach fluid would reach 70% (‘sweep efficiency’) of the copper minerals and that 75% of them would be leached for a recovery of 52% of the acid soluble copper. However, the final results from Zone 6, which had the longest leach history, showed that approximately 42% of the acid soluble copper was recovered, indicating that the `sweep efficiency’ was closer to 55%. Comparison of drill-core assay data from two holes, one drilled before (ARM158) and the other after (SMO9607) leaching, also indicate that approximately 42% of the acid soluble copper was recovered. The discrepancy between the predicted (52%) and actual (42%) recovery is probably related to a combination of factors, including difficulty in maintaining fluid saturation, channeling effects and gypsum precipitation. INTRODUCTION In situ copper leaching at the San Manuel mine, Arizona, was initiated in 1986. It was recognized that some of the copper oxide resource was not going to be economically recoverable by conventional open pit and heap leach methods using solvent extraction and electrowinning (SXEW). A high stripping ratio would be required to access part of the resource. At the time, in situ leaching was becoming popular in the uranium industry but the approach was virtually unknown in the copper industry, especially not at a large scale.

Jan 1, 2019