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By John D. Carriere, Jean Leung, Daniel. Laguitton, Michael .. J. Burrows

"The objective of this expert system application in a copper-zinc concentrator, is to increase the availability of assay data through substitution for erroneous data. The assay data is used by the Operations personnel and automatic process control strategies to control flotation circuit performance. Two online X-ray fluorescence analysis systems analyze 24 streams across four divisions to provide the required data. Data availability of individual streams average 90% while the resulting circuit availabilities are 70%. The unavailability of correct data results from mechanical, X-ray or process problems. The erroneous data can be identified by process experts using knowledge relating stream interdependencies and historical process behaviour. An expert system was devised to provide real time identification of erroneous data and substitute for that data with the ultimate aim of improving metallurgical response by both the operator and automatic control systems.The paper discusses the early development work and architecture of the knowledge base designed using Neuron Data's expert shell NEXPERT.INTRODUCTIONThis paper describes the early development of an expert system (ES) prototype at the Kidd Creek concentrator. The project is a joint undertaking of the Kidd Creek Division of Falconbridge Limited and CANMET. Kidd Creek entered into the project to apply heuristic rules to the XRF assay data to improve the metallurgical control of the flotation process by increasing availability of analysis data. This project provided a problem of suitable size and future expandability while making use of a wide base of in-house expertise and experience. Another important benefit is the introduction of expert system technology to the site providing tools and experience for future system selection and technology application. CANMET has an on-going interest in assessing various aspects of ES technology (hardware, software, knowledge engineering, integration) while addressing problems in process operations that could most readily benefit from the technique. CANMET's role in the project was to provide project assistance, financial support, substitution algorithm assistance and software for data substitution. The knowledge bases (rules) have now been completed and are to be tested in the online environment."

Jan 1, 1989

By J. Chao, C. Tan, N. Stubina

"Since J978, Falconbridge Limited has operated two electric furnaces at its nickel-copper smelter in Sudbury. As part of its S02 Abatement Program, the smelter has undergone many changes over the last seven years.This paper describes the impact of these changes on the operation of the furnaces. Some of the topics to be covered include: the installation of sidewall copper coolers; current operating conditions; and furnace heat and mass balances. HistoricalFalconbridge began smelting ores in the Sudbury area in 1930. The original smelter consisted of a 1.3 m by 3 m blast furnace and two 4 m by 6 m converters. The blast furnace was supplied with untreated mine are and molten slag/matte was discharged into a round settler.In 1933 the smelter began treating flotation concentrates. The concentrates were mixed with fine magnetic ore and flue dust, then sintered on down-draught Dwight Lloyd machines. This provided an agglomerate suitable for furnace burden which was charged to the blast furnace while still hot.Between 1930 and 1954 nickel production was increased by lengthening the 3 m furnace to 4.6 m, then to 6 m, and later by constructing additional furnaces. By 1958, the plant consisted of one 7.5 m blast furnace, a settler, and three 4 m by 9 m converters."

Jan 1, 1994

By W. L. Ennis

Introduction This paper outlines the causes of underground fires at Noranda Mines and the precautionary measures taken to guard against such fi res. Shafts There are six shafts (Figures and lA) on the property, of which N os. 1 and 2 are abandoned. Nos. 3, 4, and 5 are the present working openings from surface and No 6 is an internal shaft. No. 3 is used primarily as a service shaft, while Nos.?1 and 5 are the main hoisting shafts. Orebodies The orebodies are of two distinct types. There are the massive sulphide bodies, and the areas of mineralized rhyolite containing gold values and a silica content high enough for fluxing purposes. The massive sulphide bodies contain chalcopyl'ite, pyrite, pyrrhotite, and minor amounts of sphalerite and magnetite. The concentration of particular sulphides varies even within the same body. It is the areas high in pyrite, and to a lesser degree those, high in pyrrhotite, that are of particular interest.

Jan 1, 1950

By C. B. Webber, L. S. Diaz

"The paper presents the approach taken by Craigmont Mines to grinding circuit control. A detailed description is given of a fully automatic control system which bases its control actions on the continuous measurement of particle size in the cyclone overflow stream. The control system holds a specified particle size in the cyclone overflow, and grinds rod mi 11 ore feed at increased rates. The principles of operation of the system used for continuous measurement of particle size are described, end the improvements in mill throughput and copper recovery over several months of continuous operation are presented.INTRODUCTION Craigmont Mines Limited is located in the south-western interior region of the province of British Columbia, approximately 230 road miles north-east of Vancouver, and ten miles west of the town of Merritt. A moderate climate, good roads and service facilities provided by the Canadian Pacific Railway, Inland Natural Gas Company, and the B.C. Hydro and Power Authority, have provided a very favorable mine and plant site.The preliminary metallurgical design of the Craigmont mill was based on the test results of samples obtained from the original 2500' level drift during 1959. Pilot plant runs and other research testing for design pur¬poses were conducted at the Canadian Exploration Ltd. Laboratory, at Salmo, B.C. The design flowsheet was altered in progressive stages from 2,000 to 3,000, and finally 4,000 tons per day as the ore reserves became better defined. Construction work on the 2,400' level mill site commenced in late 1960. The official opening of Craigntnt Mines Limited took place on September 15, 1961, a little over two years from the time of the metallurgical assessment of the original ore samples.Mill throughput to date has varied widely both on a daily and a monthly basis, due to the varying hardness of the mine ores. The grindability af the ore appears to be related to the oxide iron content, which varies from lows of 9% to highs of 20%. Daily tonnage has ranged from 5,000 tons per day with 10% iron in the feed, to 6,000 tons per day with 20% iron feeds."

Jan 1, 1973

By M. P. Tibbs

An autonomous spray application system for a structural Thin Spray-on Liner (TSL) is targeting productivity and safety on underground coal continuous miners by potentially replacing steel mesh, and has broader applications as surface support and confinement in metalliferous mines and civil tunnelling. Polymer chemistry, coating formulation, geotechnical assessment and the autonomous application system are being developed as an integrated package as part of a continuous miner automation project. This polymer-based TSL system has significant benefits over conventional steel mesh skin confinement, including being more automatable by spray application, providing complete skin confinement and active skin reinforcement as a fast-curing composite with substrate, and having effective fire retardant properties for the polymer and the underlying coal. This paper presents a preliminary assessment of distance sensing systems that would enable autonomous adaptation of a nominal spray path to spray a consistent thickness of TSL (nominally 5mm) over an irregular topography. Two alternate sensors are assessed; firstly, a 2D LIDAR mounted on a linear axis is used to produce a 3D surface profile for generating an adapted spray path; and secondly, a robot end-effector-mounted ultrasonic sensor is assessed for wall following techniques to dynamically adapt a nominal spray path.

Aug 1, 2013

By S. Shokri

The increasing size and complexity of mega construction projects result in having several geographically distributed stakeholders, collaborating with each other to successfully deliver the project. Electronic Product and Process Management Systems (EPPMS) are recently emerging to facilitate the collaboration between stakeholders, reduce the surprises and issues, and improve the project productivity. These are commercially successful but evolving systems. An important component of EPPMS is the Interface Management System, which aims at formalizing and automating the communication channels between stakeholders. An interface is generally considered the link between construction elements, phases, or stakeholders. An interface Management System (IMS) involves five iterative steps: (1) Interface Identification, (2) Interface Documentation, (3) Interface Transferring, (4) Interface Communication, and (5) Interface Closing. A fundamental part of step 2 is recognizing different roles in dealing with interfaces. Each stakeholder is assigned a different role, such as responsible, accountable, consulted, and informed. In a mega project, several thousands of interfaces exist with complex relationships between stakeholders. Therefore, identifying stakeholders with higher responsible roles has been requested as useful information to the project owner in dealing with some of the project risks. After the interfaces are determined, and the responsibilities are allocated, the critical stakeholders are identified using the centrality concept in Social Network Analysis. The critical stakeholders can be determined at the highest level, considering all types of interfaces, as well as for each specific type or discipline-related interfaces. The proposed methodology is applied on a hypothetical offshore project with over 500 interfaces. In fact, this project is a simplified representation of a real scale Liquid Natural Gas project. In order to reduce the complexity of calculations and clarity of explanations, the simplified case study is used. By implementing IMS in mega projects, different parties not only formalize the communication between each other, but also gain better visibility concerning their roles and responsibilities. In addition, the owner benefits from analysing the complex relationships between stakeholders to further identify critical ones, along with other criteria like package cost, stakeholders? experiences, etc.

Aug 1, 2013

By Stewart A. Ferguson

Location.-The property consists of eight claims (P-12339 to 12343, 12403 to 12405) in Robb township, adjoining Jamieson township on the west. A mocor road extends twenty-two miles northwest from Timmins to the mine. Acknowledgments.- The field work was done in 1940 and 1943, while the writer was employed by the Ontario Department of Mines. The Metals Reserve Company has made available information regarding the property through Messrs. W. R, Dunbar, of Hollinger Consolidated Gold Mines, and W. C. Ringsleben, of the Metals Control Board, Department of Munitions and Supply.

Jan 1, 1945

By Paul J. Beck

The impact of mining development on the environment can be minimized through comp careful construction and accurate monitoring. Key to meeting these objectives is t information at all stages of design, development, operation and decommissioning. This paper will describe cost-effective means of gathering and managing reliable fiel groundwater flow and surface water regime within and surrounding the mine site, as localized contaminant plumes associated with mine operations, and monitoring ground quality. Recent research has led to the development of inexpensive, easy to install syst sampling/monitoring from different zones within a single borehole. Advances in elect developed small diameter probes and pumps for measuring water levels and taking wat continuous monitoring stations in remote areas can be colldeacttaeldo gaguetrosm aatnidc adlolwyn luosaidnegd from a central facility using telemetry systems powered by direct, battery or solar radio frequency, landline or cellular telephones, and satellite. Two case studies will illustrate the use of datalolgagregres sacnadl et eblaesmient rwyi dien mao nitoring sc and the use of multilevel samplers for managing a contaminant plume.

May 1, 2004

By Daniel Hodouin, Mélanie Proulx, Claude Bazin

"Collector and frother are commonly used to induce the floatability of valuable minerals in flotation plants. These reagents are usually distributed down a flotation bank or sometimes added in a single location at the top of the bank. A review of the literature and some experimental results obtained from laboratory and full scale trials indicate that the way flotation reagents are distributed down a flotation bank may influence the flotation response of coarse particles. The paper summarizes these observations which show that the distribution of reagents is a potential tuning variable for process optimization.IntroductionFlotation is in many cases the only way to concentrate sulphide and some oxide minerals. Flotation is a concentration process that uses particle surface composition to induce the selectivity by mean of hydrophobic reagents. The influence of particle size on flotation was firstly analyzed in the 50's1·2 and intensively investigated in the 70's, early 80's and 90's3-18. Most of the observed results show the existence of an optimum flotation size range9 whose recovery is not significantly influenced by a reduction of collector dosage""18. This result brought the idea of using a small portion of the total collector dosage at the top of a rougher bank and to distribute the remaining through the end of the bank to ensure sufficient collection of the coarse particles that need more hydrophobic coverage to attach to air bubbles and be lifted to the surface.This paper discusses the idea of using the distribution of reagents down a flotation bank to tune the operation of the process. Unlike the literature on the effect of reagents (collectors, frother...) dosage that is dense, little attention has been put on the distribution of reagents in a flotation bank. Although research on this subject has not been pushed very far, some operators have recognized the potential of a strategic addition of reagents down a flotation bank19. Except for a few exceptions, the proportions of the reagents to be distributed down a flotation bank are decided according to operator's experience instead of process analysis in relationships with particle size. This paper recalls observations made by different researchers that lead to the idea of using the distribution of reagents as a tuning variable for the flotation process. The paper does not present a detailed analysis or optimization scheme for tuning the distribution of reagents, but analyzes some plant and laboratory results with a view toward the development of a testing methodology and ultimately a validation or rejection of the idea."

Jan 1, 1998

By Jiahao Xu, Namsoo P. Kim, Guikuan Yue

Iron (ferrous ions and ferric ions) plays an important role in the heap leaching of copper sulfide minerals and copper electrowinning. In our previous study, a novel oxidation-reduction potential (ORP) equation only based on the variables of temperature and nominal ferric/ferrous ratio was developed to predict the redox potential of the quaternary H2SO4-Fe2(SO4)3-FeSO4-H2O system, and its applicability was also extended to more complex acidic iron sulfate solutions, especially those generated during the acidic leaching and bioleaching of Printed Circuit Boards (PCBs) to recover copper. In this work, the broader range of applicability of this equation to other complicated acidic iron solutions containing copper ions has been extended and determined. Specifically, synthetic iron-containing solutions with copper ions according to the conditions of industrial electrolyte during copper electrowinning and heap leaching have been used to measure the ORP and test the developed equation. It seems that this equation can still be employed to predict the redox potential of the Fe3+/Fe2+ couple for the simulated solutions under conditions related to copper electrowinning and pregnant leaching solution generated during heap leaching over a wide range of solution concentration, nominal Fe3+/Fe2+ ratio and temperature. It has shown that the prediction and measurement of redox potential is highly useful to estimate and understand the iron chemistry of industrial leaching and electrowinning processes. INTRODUCTION It is well-known that iron (ferric or ferrous) ions are widely involved in the hydrometallurgical production of non-ferrous metals such as Cu, Au and Zn, mainly in the form of acidic iron sulfate solutions. As far as Cu is concerned, in a typical leaching-solvent extraction-electrowinning process, ferric ion plays a central role in the heap leaching process and is reduced to ferrous ions in the pregnant leaching solution. Ferric ion is the most important surrogate oxidant and the dissolved ferric/ferrous couple plays an important catalytic role in accelerating the leaching rate with oxygen as an oxidant (Peters et al., 1986; Schlesinger, King, Sole, & Davenport, 2011). In addition, during the traditional electro-winning process, oxygen is evolved at the anode, and copper is reduced at the cathode. A common idea is that iron in the electrolyte in copper electrowinning cell (with total iron of 1–4.4 g/L) plays an important role in reducing the current efficiency. According to the published results (Winand et al., 1975; Dew et al., 1985; Moats et al., 2009; Khouraibchia et al., 2010), thecurrent efficiency decreases linearly with increasing ferric ion concentration and the energy consumption increase was mainly caused by the decrease in current efficiency.

Jan 1, 2019

By José Cáceres

Mine To Mill? ? Carlisle(1954) ?The economic of a fund resource with particular reference to mining?. ? Steine(1978) ?Coarser grind may mean lower metal recovery but higher profit?. ? Metalica (1999) ?Mine Plant Integrated Planning?. ? JK (2002) Mine to Mill Strategic Planning ? Camus, Kelebek (2002) ?Management of Mineral Resources: Creating Value in the Mining Business?. ? Caceres (2003) ?Integrating Milling Parameters in the Mining Planning?

May 1, 2006

By O. S. Perry, G. H. Charlewood, K. Griffin, S Ogryzlo, H. Hopkins, G. MacIntosh

"The gold mines of Kirkland Lake are in Teck township, Timiskaming district, Ontario, latitude 48°9'N. and longitude 80°3'W., at an elevation of 1,038 feet above sea-level.There are seven contiguous producing mines in a length of 3;1/2 miles along the general east-west strike of the deposits. The seven mines are, in order from west to east, Macassa, Kirkland Lake, Teck-Hughes, Lake Shore, Wright-Hargreaves, Sylvanite, and Toburn.The first discovery of gold in the zone was made by W. H. Wright in 1911 on the east claim of the Wright-Hargreaves property, and the following year the Tough brothers and H. Oakes found gold in what is now the No. 1 vein_ at the Toburn. Production began at the Toburn in 1915, followed by Teck-Hughes in 1917, Lake Shore in 1918, Kirkland Lake Gold in 1919, Wright-Hargreaves in 1921, Sylvanite in 1927, and Macassa in 1933.To the end of 1946, 31,938,350 tons of ore had been milled at the Kirkland Lake mines, from which 16,132,700 oz. gold, having a value of $498,517,600, were recovered. The bullion varies from mine to mine between 800 and 900 fine, the average for all the mines being 853. The average fineness of the native gold is 941.The workings of some of the mines are more than 6,000 feet deep and sinking to depths below 7,000 feet is now in progress.GENERAL GEOLOGYThe regional structural geology of the area in which the mines of Kirkland Lake occur is described in a preceding paper in this volume by J. E. Thomson."

Jan 1, 1954

By Jianglan Duan, Steve L. Cockcroft, Andre B. Phillion, Carl Reilly, Daan M. Maijer

"In the aluminum alloy wheel casting process, careful design of the cooling system in the die and its operation (cooling channel timing) are critical to achieve quality and productivity goals. The problem is challenging owing to the cyclic nature of the process and the relatively large thermal mass of the die in comparison to the wheel. For a given die geometry, a set of constraints have been defined to ensure directional solidification and an objective function, based on cooling rate during solidification, has been defined to reach a target secondary dendrite arm spacing. The methodology presented in this study employs the commercial finite element package, ABAQUSTM, and an optimization module based on the open source library, Scipy. The developed methodology has been applied to a series of geometries and cooling system configurations, including a 2-D axisymmetric wheel and die assembly generated from a prototype die. Preliminary testing has shown that careful selection of the objective and constraint functions have made it possible to reach desired solidification pattern.TM- Dassault Systèmes Corp."

Jan 1, 2014

By Li Qihou, Liu Zhihong, Liu Zhiyong, Yao Wei

Black copper sludge, which mainly contains copper, arsenic and a little antimony, bismuth, selenium, tellurium, is an important recyclable secondary resource. In this paper, selective removal of arsenic from black copper sludge by alkaline oxidative pressure leaching was studied. The influences of alkali concentration, leaching time, leaching temperature, oxygen pressure, liquid-solid ratio and other variables on the leaching rate of arsenic, copper and tellurium were investigated. The results were as follows: when the leaching process was conducted at initial alkali concentration of 1mol/L, liquid-solid ratio of 10, stirring rate of 500r/min, leaching temperature of 140°C for 5 h and oxygen pressure of 2.5MPa, the leaching rates of arsenic and tellurium were 85.43% and 59.7% respectively, and copper, antimony, bismuth were not leached. Hence, arsenic has been removed effectively from black copper sludge, while the valuable metals such as copper, antimony and bismuth remained in the residue that can be further recovered easily. INTRODUCTION Black copper sludge is a byproduct in the purification process of copper electrolyte. Arsenic, antimony and bismuth are major harmful impurities in copper electrolytic refining system. The accumulation of these impurities will cause adverse effects, such as the increase of electrolyte resistance and power consumption and deterioration of cathode copper quality (Wang, Liu, & Zhang, 2001). Hence, electrolyte purification is an essential part of the electrolysis process (Liang, Chen, & Guo, 2009). Electrolyte purification methods include electrowinning (Davenport, King, Schlesinger, & Biswas, 2002), solvent extraction (Navarro, Simpson, & Alguacil, 1999), ion exchange (Arroyo et al., 2017), coprecipitation (Wang et al., 2003, 2018; Xiao et al., 2007; Xiao, Cao, Mao, Shen, & Ren, 2014), activated carbon adsorption (Navarro & Alguacil, 2002), electrodialysis (Cifuentes et al., 2015), redox process (Zhou, Peng, Zheng, Ma, & Cui, 2011; Peng, Zheng, Zhou, & Chen, 2012; Zheng, Peng, Ke, & Chen, 2013), among which the electrowinning method is simple in operation and effective in impurities removal, making it the main process for current electrolyte purification. Some copper ions can react with harmful impurities to form complex black copper sludge by controlling the operation conditions of electrowinning process. Based on the estimated data provide by Davenport et al. (2002), an annual output of 400,000 tons cathode copper could produce 432-2168 tons of black copper sludge by electrowinning method. Black copper sludge contains 30~50% copper, 15~30% arsenic and a small amount of rare elements such as selenium and tellurium. Thus, recovery of valuable metals can bring huge economic interests. Moreover, arsenic in these sludges could cause significant environmental pollution. Therefore, effective removal of arsenic from these sludges is urgent and significant.

Jan 1, 2019

By William Petruk, Donald Leroux, Michael Cooper

"Brunswick's primary flotation circuit (CuPb) produces a low grade concentrate containing considerable amounts of undesirable sphalerite and pyrite. To determine the cause of the poor selectivity, a series of Quantitative Mineralogical Analyses (QMA) were performed on several CuPb circuit streams. It was observed that significant fractions of sphalerite and pyrite reporting to the concentrate was liberated, meaning that their depression was not complete. The study highlighted the need for some R&D efforts to be spent in sulphide flotation fundamentals.IntroductionThe viability of many mining projects strongly depends on the performance of their concentrators. More than ever, competitive grade concentrate and high metal recoveries are criteria of paramount economic importance. The selectivity of solid/solid separation processes used in concentrators must be maintained at high levels or continuously improved.Flotation is the solid/solid separation process used by most base metal producers. In spite of its low operating cost, flotation remains a very complex process. To make it selective, precise reagent dosages and electrochemical conditions must be maintained. The difficulty in controlling flotation lies in the numerous heterogeneous reactions that can take place between the different solid, liquid and gaseous phases involved. This complex chemistry makes flotation selectivity difficult to understand and, therefore, to improve from a theoretical point of view.Brunswick Mining and Smelting, near Bathurst N.B., operates a 10500 tpd concentrator which produces four concentrates through five stages of sequential flotation (Figure I). Various reagents are added at key process stages while the ore undergoes different electrochemical conditions. Although the selectivity is important at all stages, the performance of the very first separation, the CuPb circuit, is the most critical. It is here where mineral misplacement to the wrong stream has the greatest economic consequences."

Jan 1, 1996

By J. P. Rajot, H. Mouzannar, M. Bost

"The design of rock foundations may need to evaluate shear strength of rock-concrete interface by performing laboratory direct shear tests. A series of tests were carried out on specimens for different values of the spacing free of encapsulating material about the shear plane and different values of normal stress. Different kinds of failure were observed and not necessarily at the rock-concrete interface. The spacing free of encapsulating material appeared to be of significant influence on the test results. A mechanical analysis is presented which illustrate the influence of the loading conditions in the direct shear box on the failure mechanism. INTRODUCTIONThe design of rock foundations subjected to significant lateral loads requires defining the value of the shear strength of the interface between rock and cast in place concrete. Verifying the stability against sliding of strip footings subjected to inclined loads (SETRA, 2009) or concrete gravity dams (CFBR, 2013) are common examples where design modelling approaches imply the shear strength, sometimes the deformation behavior, of the rock-concrete interface, more or less assumed as a failure plane.Defining the behavior of rock-concrete interfaces relates to tribology. Many studies have been conducted to improve the representation of this behavior (e.g., Johnston & Lam, 1989; Kodikara & Johnston, 1994; Gu, Seidel & Haberfield, 2003; Saiang, Malmgren & Nordlund , 2005; Fishman, 2008; Eltervaag, 2013; Gutierrez, 2013), raising many questions. The behavior appeared to be influenced by many factors such as the geometry of the interface which is not planar, the roughness of the natural rock, the rock mineralogy and the concrete formulation. In addition, the study of the shear strength of rock-concrete interfaces involves considering the two different deformation behaviors of both rock and concrete. Finally, the observed failure mechanism is strongly influenced by the initial cohesion due to adhesion between the two materials when concrete is directly cast onto rock."

Jan 1, 2015

By A. Poor Zaeif Doost

With columns being installed in rougher section at Miduk Copper Complex, the rougher feed mainly reports to rougher-scavenger cells. To evaluate the efficiency of regrinding circuit, we conducted flotation experiments on samples of the feed and the products of the regrinding circuit. The grade difference of these products at 85% recovery was considered as the efficiency index. Results show that, with weight recovery of the rougher-scavengers the efficiency of the circuit increases. Exclusion of the rougher-scavenger concentrate from the feed to the regrinding circuit, resulted in an increase in the efficiency index from 10.12 to 17.6%.

Jan 1, 2012

By L. Jiang

The evolution of twinning in an AM30 Mg alloy was examined by uniaxial tension and compression testing at temperatures from ambient to 250°C and a strain rate of 0.1/s. The samples were cut along the extrusion direction from extruded AM30 Mg alloy tubes. Specimens deformed to various strain levels were examined by optical microscopy and electron backscattered diffraction (EBSD) techniques. The results indicate that the initial extrusion texture plays an important role in the formation of different types of twins and that the twinning behavior also depends on the strain path. Contraction and double twinning are the dominant twinning mechanisms in uniaxial tension, while extension twinning prevails in uniaxial compression. The different twinning behaviors are shown to be responsible for the sharply contrasting strain hardening characteristics of the experimental flow curves.

Jan 1, 2006

By Emilie Williams

The Mouska Mine uses primarily shrinkage mining to extract the narrow veins that contain its mineralization. Mining is currently occurring on levels 12 to 14, reaching depths of 800 m below surface. Although the mine is not considered ?deep?, no backfill is available to fill empty stopes and certain areas remain open for over 500 m in height. As only narrow sill pillars remain to separate the levels, a highstress environment is created. Seismic activity was first observed when mining reached Level 11 (600 m deep) and has steadily increased since then. Seismic activity is associated with the highly-stressed sill and rib pillars; no geological structures have demonstrated significant seismic potential to date. In response to this increase in activity, pillar dimensions have been increased with depth and dynamic ground support has been installed. Seismic and pressure monitoring have been implemented, among other types of instrumentation. The following paper further describes the challenges associated with using conventional methods in the high-stress environment typical of the Canadian Shield, as well as several solutions implemented to mitigate these risks.

Feb 1, 2008

By Bradford C. Wesstrom

An overview of the challenges encountered at the Freeport McMoRan El Paso Copper Refinery with higher concentrations of antimony electrolyte will be shared. The observations will cover the detrimental effects on copper starting sheets, commercial cathodes and anode slimes. The study will show negative effects on quality and productivity. Experimental work will utilize a test cell to study the effects on electrolytes by different Antimony, Arsenic concentration and anode molar ratio. Best practices will be shared for producing high quality cathodes while effectively managing the detrimental effects of higher antimony electrolyte.

Jan 1, 2014