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"The application of telerobotics to mining is currently being introduced into production systems around the world. Mining companies in Canada, Sweden, South Africa, and Australia have tended to lead the international charge to this form of technology for mining. While this introduction is taking place, a few basic questions have yet to be answered. How many machines can a single operator run? How many types of machines can a single operator run?A Canadian Research Chair in Robotics and Mine Automation has been established at Laurentian University to investigate these questions and many more through a series of experiments in a telerobotics laboratory that connects Laurentian teleoperation workstations to model mining machines at Cambrian College’s eDome. The laboratory supports many experiments allowing researchers to physically run multiple robot scenarios differing the numbers and types of machines at one quarter scale. Further experiments are being designed to investigate the potential for managing time delays in telerobotics. This paper describes the laboratory, experiments, and some preliminary results."

Jan 1, 2005

By J. E. Nesset, S. R. Rao, J. A. Finch

"For base metal sulphides, iron rejection starts in mineral processing. This review focuses on changes in plant practice specifically to improve iron sulphide rejection by control of contaminant ion effects and discusses selected general innovations in mineral processing that can be expected to play a role. One group of changes to control contaminant ions is in size reduction (the use of stage grinding and inert stirred milling) and another is in system chemistry (order of reagent addition and exploitation of the flexibility of sulphoxy reagents). Plant examples illustrate the successes, indicating that there are several options available. The general innovations start by considering the new tools for measuring gas dispersion properties and quantifying froth characteristics by imaging. Examples of their application to improve concentrate quality illustrate the potential. Other innovations stress adapting geostatistics to model variation in milling and flotation response to provide feed forward control and rigorous application of statistical experimental methodology in plant test work. An example from one concentrator shows improvements in concentrate quality from application of basic principles can be impressive.INTRODUCTIONThe more iron control (rejection) that can be accomplished in mineral processing the lower the subsequent metal extraction costs and environmental implications of iron disposal, particularly in hydrometallurgical processes. Iron rejection has been a contributing target to periodic attempts to apply mineral processing to nickel laterites and bauxites but the prime application is control of pyrite and pyrrhotite (iron sulphides) in the treatment of sulphide ores by flotation. In this paper some new concepts and innovations introduced in sulphide flotation plants over the past ten years or so (i.e., since a previous review [1]) will be outlined with examples of how they have contributed to improved “iron control”.To increase rejection of iron minerals, first the recovery mechanism should be understood. There are four principal ones, two physical in origin: 1, via locked particles (i.e., flotation of composite particles due to insufficient size reduction to liberate the minerals) and 2, through entrainment in the water reporting to the float product (an unselective process); and two originating from a response to the system chemistry: 1, true flotation (i.e., iron sulphides becoming hydrophobic) and 2, as a result of iron sulphides forming aggregates with hydrophobic particles (e.g., ”slime” coatings). There has been considerable effort to diagnose which of these dominates iron sulphide recovery; in many cases it is due to “chemistry”, in particular true flotation. The flotation effect often appears related to contamination by metal ions [1]. This can reduce selectivity in two ways: 1, metal ion species may activate iron sulphides, or 2, cause general depression which demands more vigorous flotation conditions (e.g., additional collector) with consequent loss of selectivity. This is where the review will start, by considering ways to control contaminant ions."

Jan 1, 2007

By Raphaël Mermillod-Blondin, Claude Bazin

"Sampling is an important step for ore body evaluation and daily plant material balances. The Gy’s equation is regularly used to assess the size of the samples to be collected and to estimate the reproducibility of the collected samples. The equation works well for iron and base metal ores but seems to produce pessimistic estimates of the gold content reproducibility for gold ores. A model is proposed to simulate the division of samples using a standard splitter and discrepancies are observed between the Gy’s equation predictions and simulated samples reproducibility for crushed gold ore. Results of the simulation show that sampling a pile of ore crushed to -2 mm should lead to more reproducible gold content than it is observed in practice and predicted by the Gy’s equation.INTRODUCTION With current gold prices above $1400 per troy ounce operators seek for new economical ore bodies. The metallurgical evaluation of an ore body is one of the numerous steps required to justify the investment for the development of a gold mine. Metallurgical testing requires to sample the ore body and to prepare the ore sample for the grinding and separation tests. The preparation implies crushing the ore usually to less than 2mm and its division into batches of a given weight for subsequent processing. For gold ore testing a batch of crushed ore is ground in a laboratory mill and leached using cyanide. Gold recovered in the solution is used as an indicator of the ore processing amenability. One difficulty associated with ore testing is due to the reproducibility of gold content measurements of the feed sample. According to the Gy’s equation (Gy, 1979; Morisson, 2009) the division of a 20 kg batch of -2 mm ore containing 5 g/t of gold into batches of 1 kg may lead to batches containing 5 ± 5 g/t of gold. For this reason the gold content of a feed sample is usually back calculated from the assays of the solution and solids residues of the leaching process. However, these two assays may contain measurement errors that can propagate through the calculation of the gold recovery. The use of the feed assays as a redundant information could add robustness in the evaluation of ore amenability to processing. This paper discusses the problem of sampling reproducibility for a gold ore. The analysis is carried out with reference to the Gy’s equation for the sampling of particular materials."

Jan 1, 2012

By D. Van Tonder, C. Edwards

ABSTRACT Solvent extraction is used in many acid leach uranium circuits to upgrade and purify the uranium-bearing solution prior to final product precipitation. A number of strip options are available to recover the uranium from the loaded organic. This paper compares seven of these options on the basis of typical capital and operating costs for the solvent extraction circuit and downstream uranium processing and also considers other related issues. The aim is to provide an objective comparative assessment of these options that could be used as a qualitative guide in process selection or improvement.

Jan 1, 2013

By D. M. May

"Cut-and-fill mining is a stoping method that has been widely utilized in the mining industry over the past forty years. It took preference over shrinkage methods at Levack in the early 1930sbecause of its safety aspects; i.e., prompt support of the stope sidewalls, good working floors and better accessibility to support poor back areas. In addition, higher recoveries of ore were possible because of the flexibility of the method in that silling could take place easily at any horizon; low-grade ore could be sorted and left in the stope as fill and certain zones of rock could be left unmined. With modern techniques, a steady production rate can be established, as filling and mining can be carried out stimultaneously.AIthough there are numerous variations of cut-and-fill mining throughout the world, this paper reviews the original type of mining, with modifications and improvements through the years to present modern practices, with the Levack West operation appearing to be the most productive at this time. Stoping efficiencies have also increased substantially from the original 10 tons per manshift to the present 55 tons per manshift.The paper also outlines the many improvements that have been made with respect to mucking and ground support operations; from hand mucking in a single stope to the use of frontend loaders and haulage trucks in fully accessible stope complexes; and from timber props to roof bolts of various types. Although present methods are extremely satisfactory, experimentation is continually being conducted to improve safety and productivity for future mining.IntroductionThe major mining operations of the Ontario Division of Inco Limited are located in the Sudbury Basin (Fig. 1). Around the rim of this geological formation and within 30 miles of the City of Sudbury are nine producing mines and one ' open pit operated by the company .Ore production currently approximates 11.5 million tons per annum from underground and open-pit operations. Underground mining methods include sub-level caving, shrinkage, cut and fill, undercut and fill, blasthole and vertical retreat. The Levack Complex, the main plant of which is the central Levack Mine, produces 11,000 tons per day.The first prospecting in the Levack area, in 1887, was conducted by James Stobie, who examined rock cuts along the route of the Canadian Pacific Railway to the northwest of Sudbury. However, it wasn't until 1913 that operations commenced at Levack under the Mond Nickel Company."

Jan 1, 1981

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 Nick D. Rose

The importance of structural geology in open pit slope stability is overlooked in many mining operations due to pressures to cut costs and minimize mine personnel. As a result, mine geology staff are often unable to keep up with geological mapping of the pit slopes due to other day to day production oriented tasks. In some instances, key structural controls that contribute to slope instability may not be identified until after a slope instability has initiated, at which time it may be difficult or impossible to delineate these features in the field. Even for small slopes, understanding the engineering and structural geology of the rock mass, as well as the effects of groundwater and blasting practices, are of key importance to slope stability. Two case histories are presented as examples of mining operations that experienced slope instability with little more than anecdotal information about the structural and groundwater conditions encountered during mining. By conducting field reconnaissance, simple slope stability analyses and ongoing slope monitoring, practical remedial measures were implemented, allowing continued safe mining operation.

May 1, 2002

By Steve Custer, Tim Kahl, Sue Parker

"The primary objective of the Barrick Goldstrike expert system is to achieve the desired liberation size for the autoclave circuit while maximizing throughput. In addition, when downstream limitations (autoclave circuit or others) restrict the milling circuit tonnage the expert system further improves grinding product size. Since its implementation, the expert system has provided expected throughput improvements while improving or maintaining circuit performance.Barrick Goldstrike and MinnovEX Technologies Inc. teamed up to install an expert system to control Line I and I1 of the autoclave grinding circuits. The dissimilar equipments of the two grinding circuits coupled to different production objectives, skepticism among operators, and the variability of the ore types processed in each line challenged the implementation.To ensure implementation success, Barrick Goldstrike dedicated four administrators full time to the project. The system administrators included two metallurgists, a process control engineer and a mill trainer. As usual, the control room operators were the experts who provided the operational logic for the foundation of the control system. The administrators and all eleven of the control room operators signed off on acceptance of the system. Current online utilization is 95%.INTRODUCTIONThe grinding circuit for Barrick Goldstrike’s autoclave process consists of two SAG Mill Ball Mill lines. Line 1 grinding circuit is comprised of a 22 by 8 foot, 2500 horsepower Allis Chalmers (AC) variable speed SAG mill, followed by a 12.5 by 14 foot, 1250 horsepower AC ball mill, and a 13.5 by 18 foot, 1800 horsepower Dominion ball mill in parallel. SAG mill recycle from the primary discharge screen (+5/16 inch) is processed through a 1352 Nordberg Omnicone crusher (4.5 foot). A secondary SAG discharge screen (+1/8 inch) closes the SAG circuit. The ball mill circuit is closed with 6 Krebs super D20 cyclones. Line 2 grinding circuit is comprised of a 24 by 12 foot 4000 horsepower Fuller variable speed SAG mill followed by a 16.5 by 30.5 foot 5000 horsepower Fuller ball mill. SAG mill recycle from the primary discharge screen (+5/16 inch) is processed through a 1560 Nordberg Omnicone crusher (5 foot). A secondary SAG discharge screen (+1/8 inch) closes the SAG circuit. The line 2 ball mill circuit is closed with 12 Krebs super D20 cyclones. The underground Meikle ore is typically fed through Line 1. Achieving the desired product size is critical for successful processing of Meikle ore. Open pit Betze ore is fed to Line 1 when Meikle ore is unavailable. Line 2 processes Betze ore exclusively. Throughput is maximized when processing Betze ore as the product size is less critical. The products of these two circuits are combined as feed to the autoclave circuit. The ore types and the autoclave circuit demands determine the required grinding circuit product size and maximum combined mill feed tonnage."

Jan 1, 2001

By G. Styles, K. Lye, R. Tenbergen, M. Mayhew

Requirements to produce a higher bulk concentrate grade have necessitated extensive use of on-stream analyser data and computer programming to obtain the targets set for Frood Stobie Mill as required by overall milling considerations.A brief history of milling process changes associated with the changes from a low grade (3% Ni) bulk concentrate in the sixties to a high (6 to 8.5%). Nil bulk concentrate currently will be presented.The heart of the presentation will be the computer control schemes for ""self optimisation"" of the distinct flotation sections in the plant within certain restraints to achieve targets set by the mill metallurgist.

Jan 1, 1985

By A. R. Miller, G. Desrivières, T. MacKinnon, H. Bursey, M. C. Bétournay, B. Replogle, D. L. Barnes, P. Laliberté

"A mine production locomotive, the world’s first applied industrial fuel cell vehicle, has been designed and tested in the context of a number of proof-of-concept projects supported by the Fuelcell Propulsion Institute, an international consortium of stakeholders dedicated to facilitate the commercialization of fuel cell vehicles.The locomotive’s simple electric-powered motor and controller system was ideal to study a number of requirements related to fuel cell power application: hydrogen power plant operation, underground hydrogen use, risk and regulatory requirements, production performance versus the conventional battery- powered locomotive version under measured duty cycles and production requirements, power plant design improvements for other fuel cell vehicles, and cost benefit aspects.This article will focus on the design and testing aspects of this project which has led to successful performance demonstrations of the vehicle under surface and underground conditions at two mines. It will also present information on the creation of a safe, reliable, and efficient power plant that fulfilled its design objectives, including longer productivity time for a given vehicle fill-up."

Jan 1, 2004

By M. Ramström

"In 2002, Atlas Copco Rock Drills AB released the new rig control system (RCS) technology for all of its drill rig types. RCS opened the way for a new generation of computerized drill rigs based on modern, standard PC-computer technology. Drilling accuracy, information logging, reduction in manpower in some types, and serviceability have all taken a quantum leap forward when compared with previous generations of drill rigs. RCS is modularized and distributed by means of CAN-bus technology. This technology, which is well proven in automobile applications, forms the communication backbone of the rig. The modularity facilitates almost unlimited possibilities for the expansion and adaptation of drill rig functions."

Jan 1, 2005

By C. J. Brown

Controlling the level of impurities in copper refinery electrolytes is essential to achieving acceptable cathode purity. Purge of electrolyte is not an entirely satisfactory solution since the cost of neutralization, waste disposal, and replacement acid can be appreciable. The APU® process utilizes ion exchange resin to sorb sulphuric acid while rejecting metal salt impurities. Extensively employed for recovery of waste pickling and anodizing acids since 1977, the system is now being used at several refineries for removal of contaminants such as antimony, bismuth, iron, and nickel. The purified acid, which is recovered from the resin by water elution, is recycled back to the refinery tank-house, while the metals are typically recovered from the de-acidified by-product solution by precipitation.

Jan 1, 2005

By C. Taschereau, G. A. Vickell, A. R. Laplante

Evidence in support of an iron-gold corrosion cell during the high-temperature/highpressure elution of loaded carbon is presented herein including, but not limited to, its discovery, mode of genesis, and confirmatory laboratory testwork. A discussion of metallurgical and economic impacts, remedial investigations, plant design considerations, and future work including mitigative possibilities is presented.

Jan 1, 2006

By Arthur L. Holloway, James C. Mugford

"The Underground Research Laboratory (URL) is located in southeastern Manitoba, in the Lac du Bonnet granite batholith of the Canadian Shield. It was constructed by Atomic Energy of Canada Limited (AECL) to conduct geotechnical research for the Canadian Nuclear Fuel Waste Management Program, assessing the concept of permanent disposal of nuclear fuel waste deep in plutonic rock.One of the primary objectives of the research program at the URL is to develop a nondestructive rock mass characterization method that can be used during siting, design and construction of a used fu el waste disposal vault. An experimental program was established to assess radar reflection profiling as a technique for fracture characterization in granite. The highly resistive, homogeneous nature of the Lac du Bonnet granite is ideal for the propagation of electromagnetic energy at the radar range of frequencies and water-filled fracture zones act as excellent reflectors because of their contrasting electrical properties.Radar reflection profiling was undertaken to characterize a major fracture zone located between 5 m and 10 m below Room 211 on the 240 m level of the URL. The profiling was done at a frequency of 120 MHz, on a 1m grid laid out on the bare rock floor of the room. Reflectors identified in the analog data were correlated between the profile lines, digitized, and a three-dimensional surf ace for each recognizable reflector was constructed. These surf aces were then compared with data obtained from the examination of numerous cores from adjacent boreholes intersecting the fracture zone. A very good correlation was found between the major radar reflectors and the most intensely fractured regions of the zone. Modelling studies also showed that a series of prominent shallow radar reflectors were caused by a borehole drilled close to Room 211."

Jan 1, 1990

By J. R. Hart, V. C. Smith, V. P. Babarovich-Hansen, J. H. Schubert

"An introduction and case study of Mintek's latest generation of Milling Circuit controller, the MillStarTM with IES (Interpreting Expert System) is presented. This paper also describes as a case study its installation on a Southern African base metals concentrator plant which has demonstrated improved operation, greatly reduced variation in product quality, as well as increased capacity and availability of the circuit.In this case study, the MillStarTMw as installed along with several other enhancements, including hydrocyclone underflow monitoring, product particle size estimation and flotation circuit stabilisation. MillStarTM utilised the particle size measurement to control grind to within 2% of setpoint, all the while ensuring sump level control, density control as well as mill power optimisation. Mintek' s expertise in the modelling of tumbling mills allowed the development of a specialised optimising controller that ensured the mill was kept in the most efficient operating region.MillStarTM augments the automatic control with useful user interface features, such as on-line trends of any logged variables, historic data warehousing and retrieval and production summary reports.A novel feature that distinguishes the MillStarTMi s the IES (Interpreting Expert System). This is a feature of the software that works with the automatic control code to generate explanations for control actions made by the controller. Often complex control systems are mysterious in nature, reducing trust and eventually resulting in them being switched off. The IES method of exposing the heart of the controller has proved popular and is seen to have potential as a training tool. 314"

Jan 1, 2000

By P. A. Mingione

"AEROPHINE@ 3418A is a unique sulfide mineral promoter produced by Cyanamid, based on phosphine (PH3) chemistry. It has proven effective as a collector for the sulfide minerals of copper and particularly lead (galena), as well as for secondary gold and silver values. AEROPHINE 3418A has widest application as a Cu and/or Pb collector for complex ores of Cu-Zn and Pb-Zn, which frequently have significant quantities of associated precious metal values. Advantages shown in the use of AEROPHINE 3418A are improved selectivities against Zn- and Fe-sulfides, increased precious metals recoveries, reduced total collector consumptions for Cu and/or Pb flotation, and increased flotation kinetics leading to higher recoveries of these values. Operating plant, pilot plant and laboratory test data from treating different ores are presented, demonstrating the advantages in use and preferred application of AEROPHINE 3418A.INTRODUCTIONCyanamid operates the only phosphine and phosphine derivatives plant in North America, located in Niagara Falls, Ontario. Specialty chemicals manufactured at this facility are used in many diverse applications, including solvent extraction reagents and textile flame retardants. A unique phosphine-based sulfide mineral promoter, AEROPHINE 3418A, is also produced. The origins of AEROPHINE 3418A promoter date back to the 1960's, when it was established that sulfide mineral collectors based on phosphine chemistry demonstrated efficacy. This new collector chemistry was found to provide flotation performance differing significantly from those of more traditional thiol collector chemistries such as xanthates, dithiophosphates, mercaptobenzothiazoles, thionocarbamates and those with xanthogen groups. Some of the advantages ultimately demonstrated by AEROPHINE 3418A promoter compared to these traditional collectors include:"

Jan 1, 1990

By Ingrid Hann

The Triple Bottom Line ? Economic Sustainability ? Creation of Joint Venture companies ? Planned evaluation of other kimberlites ? Social Sustainability ? Impact Benefit Agreement and Participation Agreements ? Education and training initiatives ? Environmental Sustainability ? Environmental management ? Mine closure planning

May 1, 2008

By Jan E. Nesset, Julie Fournier, Jorge Torrealba, Colin Hardie

"Gas dispersion studies have been used to benchmark and optimize plant flotation performance for more than a decade, although this technology is not as widely in use as it likely should be based on the significant improvements that have been reported. Part of the reason may be a general lack of awareness within the industry of just what these improvements have been. This paper reviews a number of the reported case studies, groups them into categories of improvement, and draws some general conclusions. The paper will be of interest to plant engineers and technology providers seeking new approaches and tools for improving their own and clients’ processes.INTRODUCTIONThe sector of flotation hydrodynamics that is now known as gas dispersion technology, and the corresponding terminology, had its beginnings in the 1980’s and early 1990’s in the laboratories of McGill University where the students of Prof. J.A. Finch and Dr. C. Gomez conducted studies of gas holdup, superficial gas rate and water recovery on laboratory flotation columns (Laplante et al., 1983; Xu et al., 1991;, Banisi and Finch, 1994; Finch et al., 1999; Nesset, 2011). Sensors were developed for gas holdup (eg), gas rate (Jg) and bubble size (Db) distribution (Tavera et al., 1996: Finch et al., 1999; Dahlke et al., 2001; Chen at al., 2001; Hernandez-Aguilar et al, 2002, 2005). The sensor measurements were rapidly adapted for use in mechanical flotation machines in plant environments (Gomez and Finch, 2002; Gomez et al., 2003; Cooper et al, 2004; Torrealba-Vargas et al, 2004; Nesset et al., 2007). Somewhat parallel developments were being conducted by Gorain and colleagues at the University of Queensland’s JKMRC on pilot and industrial flotation machines using the McGill approach but utilizing alternate sensor designs for eg, Jg and Db (Gorain et al., 1997, 1999; Schwarz and Alexander, 2006) to link flotation kinetics to bubble surface area flux (Sb). Early industrial applications were those led by the university teams from McGill (Canada), the JKMRC (Australia) and the University of Santa Maria (Chile) at plants in North and South America, Australia, South Africa, Asia and Europe. Industrial organizations that brought the technology on-board in the early 2000’s included Teck Resources (then Teck Cominco), COREM, Vale (then Inco), Anglo American Platinum. Several of the major flotation cell manufacturers also purchased the McGill bubble viewer technology for their own equipment studies. The sensors have continued to evolve with multiple and continuous measurement of Jg (Torrealba-Vargas and Finch, 2006, Bartolacci et al., 2008), gas holdup by acoustic means (O’Keefe, 2007) and a combined Jg-Db device called the Anglo Bubble Sizer (Harbort and Schwarz, 2010). A review of the gas dispersion technology use and development have been provided by Gomez and Finch (2002), Harbort and Schwarz (2010) and Nesset (2010)."

Jan 1, 2015

By T. Hidayat, D. Shishin, S. Sineva, M. Shevchenko

The effects of the slagging components Al2O3, CaO and MgO on the thermodynamics and phase equilibria of the gas/slag/matte system with major elements “Cu2O”-“FeO”-SiO2-S are characterised using an integrated experimental and thermodynamic modelling approach. The experimental technique included high-temperature equilibration experiments using a spinel substrate in controlled gas atmosphere (CO/CO2/SO2/Ar), quenching of the sample and subsequent measurement of the compositions of equilibrium phases with Electron Probe X-ray Microanalysis (EPMA). Thermodynamic modelling is undertaken using the computer system FactSage. In previous experimental studies on this system, the separate effects of Al2O3, CaO and MgO were determined. In the present investigation, the combined effects of these additional components are investigated at 1200oC and P(SO2) = 0.25 atm and a range of P(O2)’s. Special attention is paid to ensuring chemical equilibrium is achieved in each case, for this reason possible kinetic factors are systematically analysed. The results obtained are presented in the form of graphs showing the compositions of matte and slag phases as functions of copper concentration (matte grade). The new experimental data are used for the improvement of the thermodynamic database for multicomponent copper-containing systems. The effects of the slagging elements on this multicomponent system will be presented in the paper. INTRODUCTION Whilst Fe-O-Si form the principal components of copper smelting and refining slags, additional impurities are present in industrial practice typically at 2–5 wt.% Al2O3, 1–4 wt.% CaO and 1–2 wt.% MgO levels (Davenport, King, Schlesinger, & Biswas, 2002). These elements are introduced into the slag as impurities in concentrates and other feedstocks, in fluxes added to the process and in refractory materials. Understanding, and accurate description, of the changes that take place in the smelting process in the presence of these additional elements is of major importance to the optimization of industrial operations. Although experimental data are available on slag/copper matte equilibria, further work is needed to accurately characterise the influence of Al2O3, CaO and MgO on phase equilibria and elemental distributions of elements in gas/slag/matte systems. The individual effects of the Al2O3, CaO and MgO slagging components on equilibrium phase assemblages under selected conditions have been quantified in a recent series of studies on the Cu–Fe–O–S–Si-(Al, Ca, Mg) gas-slag-matte-metal system (Fallah- Mehrjardi, Hayes, & Jak, 2018; Fallah-Mehrjardi, Hidayat, Hayes, & Jak, 2017a, 2017b; Hidayat, Fallah-Mehrjardi, Hayes, & Jak, 2018a, 2018b; Jak et al., 2016; D. Shishin, Decterov, & Jak, 2018; Denis Shishin, Hayes, & Jak, 2018). Since, thermodynamically, the condensed phases do not behave ideally, it is to be expected that the effects of individual elements may not be additive, and the additional interactions between the Al2O3, CaO and MgO slagging components will also have to be taken into account. These additional effects are expected to be smaller than those of the individual components, so higher accuracy is needed. The present paper describes analysis of the precision and accuracy of the experimental technique on multi-component, multi-phase equilibria in these systems to enable the combined effects of Al2O3 + CaO + MgO on slag/matte/spinel equilibria, i.e. for high Fe/SiO2, to be accurately measured. The effects of Al2O3, CaO and MgO on the gas - slag - matte are analysed using a thermodynamic modelling approach with the computer package FactSage.

Jan 1, 2019

By B. M. Coombes

The McCracken and Stacey (1989) method of assessing geotechnical risk for largediameter raisebored shafts has been the basis for most Australian pre-construction raisebore investigations for the past 20 years. At the time of its publication, the McCracken and Stacey (M&S) Method did not include a database of raisebore diameter and rock mass conditions versus actual performance. It did, however, provide a chart that quantified geotechnical risk in terms of proposed shaft diameter and the raisebore rock quality index, QR. Two parameters, RQD/Jn and Jr/Ja were identified as being critical to raisebore stability, but the contribution of these to overall raisebore stability was not quantified. Peck and Lee (2008) published a database of raisebore performance from Australian case histories. Raisebore diameter and ground conditions, in terms of a Lower Bound QR value, were presented for 50 cases versus raisebore performance. This paper updates the database with further case histories and corrected SRF values. This paper further evaluates the reasons for the variable raisebore performance for similar RSR values. For all case histories, three parameters, RQD/Jn, Jr/Ja and Jw/SRF are investigated to assess their influence on raisebore performance.

May 1, 2011