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By K. L. Eastwood

The ISA PROCESSTM cathode plate is characterised by its copper coated suspension bar, coupled with a blade employing austenitic stainless steel alloy 316L. The blade material has become the mainstay of the technology and has been closely copied by competing cathode designs. Improvement to the cathode plate design remains a key area for research, and ongoing developments by Xstrata Technology's ISA PROCESSTM have recently been commercialised. Two such developments are the ISA Cathode BRTM and ISA 2000 AB Cathode. The ISA BR cathode is a lower resistance cathode that has proven to enhance operating efficiencies. The AB cathode was designed to improve stripping inefficiencies in the ISA 2000 technology. These developments have now had time to mature and their long term performance will be discussed. Rising material costs and the desire to extend the operating boundaries of the standard 316L cathode plate has triggered a number of significant advances. These involve the use of different stainless steels as alternatives in some operational situations. The technical aspects and results of commercial trials on this development will also be discussed in this paper.

Jan 1, 2007

By J. H. Gasper

The overall success of steep slope (>20°) contour mining is dependent upon many factors. The major factor is the selection of the mining method that best suits the premining site conditions both environmentally and economically. These conditions can be divided into three major categories: 1) Geometric Conditions --machine limitations, slope stability restrictions, erosion capacity, among others; 2) Physical Conditions--material properties, rock strengths, diggability, driving surfaces, among others; 3) Chemical Conditions --acid/base relationships, blending or selective placement of overburden, among others. This paper incorporates these conditions through conceptually modeling compliance oriented contour mining methods; in particular Haulback methods, utilizing: 1) the Front-End Loader (FEL)/Truck; 2) Tractor Scrapers; and 3) Combined FEL-Truck/Scraper. Engineering analyses including machine selection, sequencing, ease of varying production rates, slope requirements (for stability and running surfaces), drainage requirements and many others can be performed after the geometric constraints dictated by in-situ conditions and regulatory requirements have been conceptualized. Once all generalized geometries have been established, reduction to idealized three-dimensional views is achieved. These are then reduced to two-dimensional symbolic models, mainly plan views, but also elevations and sections. Equipment activities and operations are then conveniently overlayed. Without this simple two-dimensional reduction, technology transfer remains awkward and non-analytical.

Jan 1, 1991

By Clyde L. Smith

Since the early 1950's exploration in the Yukon Territory, Canada, has been confined largely to Selwyn basin where at least five large stratiform or massive sulfide Pb-Zn deposits have been discovered. The five ore bodies total nearly 100 million tons of 10-16% combined Pb-Zn with 1-3 oz./ton Ag. The only deposit currently in production is the Anvil Mine operating at 8,000 tons per day. Beginning in 1972, exploration in the Mackenzie Mountains, east of Selwyn basin and west of Mackenzie arch, resulted in finds of Mississippi Valley type Zn-Pb mineralization in a belt of Proterozoic and Lower Paleozoic carbonate rocks (Figure 1). Four districts have been located and intensive exploration by numerous Canadian and Arnerican mining companies is currently in progress over a length of 400 miles in the carbonate belt. The consensus is that a major new Zn-Pb province may be taking shape.

Jan 1, 1974

By E S. Bernard

Steel fibre reinforced shotcrete (SFRS) is increasingly being used as ground support in both civil and mining applications. In recent years, methods of assessing the performance of SFRS have been developed. These include the beam test such as that prescribed by ASTM C-1018 and the panel test prescribed in the EFNARC European Shotcreting Standard. The panel test has gained popularity in recent times due to the two-way action modelled in the test. However, some difficulties have been noticed. Shear failures sometimes occur and there appears to be a rather high degree of variability in the panel test results. A new method of testing panels has been proposed. A circular panel supported on three symmetrically arranged points has been assessed at the University of Western Sydney. This paper describes the new test which may be the basis of a new specification for the testing of toughness of SFRS and summarises research work which has been carried out to-date.

Jan 1, 1999

By Matthew Price, Laura Brown, Atulya Verma, Samantha Espley

Burst-prone conditions are a significant hazard in deep hardrock mines, elevating the risk to excavation stability and, more importantly, to worker safety. As mining progresses deeper, induced stress changes may trigger the initiation of rock failure processes which can be detected and recorded as mine seismicity. The implementation of seismic monitoring and routine seismic data analyses enables mine seismicity to be quantified spatially, temporally and on scale. The ability to quantify and characterize mine seismicity offers the opportunity to gauge seismic hazard, identifying high risk zones for mitigation against burst-prone excavation failure. Over the last decade, the Mines Technical Services (MTS) group at Vale Canada Limited’s Garson Mine assessed seismic hazard with the objective of assigning practical mitigating controls to zones identified as having a high rockburst potential. Initially, seismic hazard was computed using the Seismic Excavation Hazard Mapping (SEHM) software developed by the Mining Innovation Rehabilitation and Applied Research Corporation (MIRARCO) at Laurentian University, Canada. More recently, Vale Sudbury Operations partnered with the Australian Centre for Geomechanics and the University of Western Australia’s mXrap consortium. Through the consortium partnership, MTS at Garson Mine implemented the mXrap seismic data analyses platform, including the grid-based seismic hazard assessment tool. Building on 10 years of seismic hazard assessment experience at Vale Garson Mine, this paper summarizes a comprehensive case study, comparing the two tools (SHEM and mXrap) used at Garson Mine to assess, quantify, and represent seismic hazard. Subsequently, results of the Garson Mine comparative seismic hazard study will be discussed, emphasizing the need for an all-inclusive hazard assessment tool, focused on delivering practical mitigating controls that further enhance the overall safety of seismically active underground mines.

Apr 26, 2022

By Alexander Sutulov

It is calculated that since the beginning of last century, which practically coincides with the beginning of the Industrial Revolution, our civilization has consumed around 239.5 million tons of copper (see: Table 1). According to the most pessimistic projections of today, with only a 2.5% annual growth rate in demand, we are bound until the end of this century to consume another 200 million tons of copper in remaining 17 years. A recent study made by US Bureau of Mines (1) indicates that the proven ore reserves of 150 major operating mines and about 120 deposits sufficiently explored for development and feasibility studies accumulate a total mass of 49.3 billion tons of ore, assaying an average of 0.82% Cu and containing around 324 million tons of recoverable copper. Consequently, there is a high grade of probability that the bulk of our future ore supplies, for our demand of, say, next 25 years will cane precisely from these mines. The interesting point in USBM study is that it indicates the recoverable byproduct content of these ores and which is: 118.2 million troy ounces of gold 2277.4 million troy ounces of silver 7.1 million tons of lead 24.7 million tons of zinc 1.3 million tons of nickel 3.1 million tons of molybdenum 765 thousand tons of cobalt, and 720 thousand troy ounces of platinum. This information gives us a relatively reliable profile of our future ores for next 25 years, and thus makes possible evaluation of byproduct credits in our future copper mining and producing activities.

Jan 1, 1983

By E. O. Wagner, V. F. Parry, J. B. Goodman

C. P. HEINER*—If you take out 35 pct of the total weight of the coal in the form of moisture, would that be about what it was in the case of North Dakota lignites ? V. F. PARRY (authors' reply)—That is about it. C. P. HEINER—That will be about a 35 pct loss and the final product will be about 11,000 Btu? V. F. PARRY—That is right. The heating value of the dried lignite is 10,000 to 11,000 Btu. C. P. HEINER—And the thought is not, then, to produce a commercial coal with that heavy loss, but to make other products—that is, synthetic fuel base, is that it? V. F. PARRY—The principal thought is to upgrade the coal, making it a more favorable raw material for industrial purposes, both for shipment and direct use. You see, the trouble in these lignites is that their moisture penalizes their

Jan 1, 1950

By M. A. A. de Klaver

Due to the current cost and availability of crude oil in Brazil, Samarco Mineracao S. A., as part of its program of quality and productivity optimization and reduction of operating costs, has undertaken tests to utilize alternate energy sources for fuel oil used in its pelletizing plant at Point Ubu, Espirito Santo, Brazil. The energy program undertaken by Samarco consists of two basic steps. The first step was to reduce energy consumption, that is, to improve the thermal efficiency of the process. Secondly, a program was started to substitute the fuel oil with coal.

Jan 1, 1984

By John J. J. Chen, Barry J. Welch

"As in many industrial processes, the detailed mechanisms involved must first be understood before being able to redesign, or to carry out improvements or optimisation of the process and equipment performance. In a great majority of metallurgical processes, visual observation and actual measurement of process variables are either very difficult or near impossible. Often, the cost and effort involved are prohibitive. Consequently, physical modelling is often used to provide some understanding of the process and for the validation of computer numerical models. In this paper, we summarise some of the work carried out at The University of Auckland on the modelling of the Hall-Héroult electrolytic cell, the in-line melt treatment process, and the steel casting tundish. IntroductionIn any industrial process, it is essential to understand the underlying mechanisms before any optimization or process improvement can be carried out. In many metallurgical operations, the processes are conducted at elevated temperature and under rather hostile environments. Consequently, it is often difficult, and sometimes impossible, to observe the actual processes occurring, or conduct measurements which are pertinent. In some situations, it is possible to formulate mathematical equations purported to describe the process, and obtain the solutions numerically. However, in this latter case, the validity of the simplifying assumptions made are often uncertain. Physical modelling may provide the necessary information for the validation of such numerical models. Furthermore, through an application of the principle of similitude, it is possible to apply data obtained from physical modelling to actual metallurgical processes. This paper will summarise some the work carried out at The University of Auckland on the physical modelling of gas-induced flow in the Hall-Héroult electrolytic cell, an in-line melt treatment unit, and the flow in a steel casting tundish.Gas-Induced Flows in a Hall-Héroult CellIn an aluminium cell, the effects due to electro-magnetic forces have been addressed and various design modifications such as magnetic shielding and the positioning of risers have been carried out to control or lninimise the effects of magnetic fields'. Consequently, the effects of gas-induced flows are now becoming significant providing the impetus for the study of the gas behaviour in the bath. Furthermore, the shape and size, and the rate of evacuation of the anodically generated gases affect the cell voltage affecting the energy efficiency; at the same time, the back-reaction between the anode gas and the metal produced is the predominant cause of the loss of current efficiency. Figure 1 shows a cross-section of a conventional cell in which the gas evolution occurs directly under the anodes, and the gas induced flow is confined mainly to the region occupied by the bath"

Jan 1, 1994

By R. S. Olson

An analysis of the wash thickener-two stage filtration circuit was undertaken to quantitatively describe the circuit performance. On the basis of information developed in this study, the factors of major importance in reducing soluble loss are: filter wash, wash zone size, filter capacity, filter feed pulp dilution, blow back, filter cloth, water to repulp, water to primary wash, water to feed pulp and thickener underflow. The wash thickener-two stage filtration circuit has been used in many hydrometallurgical plants to separate solute from leach solids. As many as 20 to 30 plant operating variables determine the performance of the wash circuit and hence the soluble loss. The complex relationships of these variables, with each other and with soluble loss, make the evaluation of their effect on mill performance difficult. An analysis of this type of circuit was undertaken to quantitatively describe the circuit performance. THE CIRCUIT The diagram in Fig. 1 represents the operation of the wash thickener-two stage filter circuit. This circuit provides for counter current, cross current or for a combination of countercurrent-cross current operation. The feed pulp stream, J, is intended to include any solution or water, other than primary and secondary filtrate, which enters the wash thickener. Except for filter washing, the operations in the circuit are simple mixing operations which can be described by material balance. The concentration of solute in the filtrate and cake solution after application of wash liquor cannot be described by simple material balance. The displacement washing equation, derived by Rhodes1 and extended by Choundhury and Dahlstrom,2 appears to best describe this case of miscible displacement in porous media. In a useful form, it is

Jan 1, 1963

By Franz Ramstorfer

No lingotamento contínuo de placas, rompimentos de veio pelo colamento e problemas de qualidade de superfície, como trincas longitudinais, são frequentemente relacionadas à lubrificação insuficiente no molde de lingotamento contínuo devido ao pó fluxante ou a prática de oscilação inadequados. Para detectar, com vistas a prevenir, este tipo de problema de processo, um método para avaliar em tempo real o coeficiente de atrito entre o veio e as placas do molde foi desenvolvido, utilizando-se a medição da força que atua nas placas laterais do molde e as forças de oscilação. Observou-se que o coeficiente de atrito do molde é um parâmetro confiável para auxiliar no desenvolvimento de pó fluxante, na otimização de parâmetros de oscilação e no monitoramento online do desempenho de pó fluxante.

Aug 16, 2017

By C G. Ferguson, S L. Makin

The Cawse nickel project is a new generation pressure acid leach (PAL), solvent extraction and electrowinning process used to produce LME grade nickel metal and cobalt sulphide concentrate containing 40 per cent cobalt by treating nickel and cobalt oxide ores from a lateritic ultramafic profile. The project is located 50 kilometres NW of Kalgoorlie in Western Australia. The commercial success of the Cawse nickel operation is dependent in part upon the ability of the principal ore type to be beneficiated. A simple process of rejecting lower grade material on the basis of particle size achieves this. The process is called upgrading and allows subgrade material to become commercial ore grade and also allows higher ore grades to be processed in the early parts of the operation. The success of the upgrade process is dependent upon the physical and chemical properties of the ore being processed and the nickel grade of the ore. The upgrade ore type represents >80 per cent of the Cawse nickel resource and is hosted mostly within a limonite unit, represented by goethitic clays in the upper saprolite zone. In the upgrade processing circuit the ore is crushed and slurried. It is then passed over a series of screens that remove all material over 0.5 mm. This ensures that coarse material is removed from the main ore stream. Upgrade is reliant on selectively rejecting lower grade or barren material, which can include silica, magnesite and relict saprock. To predict leach feedgrade, the grade control estimates the head grade and upgrade percentage for all ore delivered to the run of mine ore pad. To do this reverse circulation (RC) drill holes are logged for ore type, assayed for a range of elements and undergo simulated upgrade testwork. The percentage and grade of material rejected through the upgrade circuit has the most influence on upgrade per cent. This reject is determined by the physical properties of the rock mass and drum scrubber parameters. The correlation between nickel upgrade and reject can be established to predict upgrade from the known mass reject. Parcels of upgrade ore milled to date closely follow projected correlation trends. Upgrade circuit results have been excellent, with average nickel grades upgrading by 34 per cent, cobalt by 23 per cent, with 55 per cent mass passing.

Jan 1, 2000

By Donald F. Reed

In its investigation of old, abandoned, lead-zinc mines at which records of operations are not available, in 1914 the Bureau of Mines dug surface trenches anti', in 1947 It diamond-drilled three holes at the Albright Farm deposit in Sinking Valley. Some good lead-zinc ore had been extracted from veins in dolomitic limestone during the time of the American Revolution and as late as 1870. Since that time the only activity was sporadic prospecting and developing. Thu Bureau of Mines disclosed two additional veins by surface trenching, but diamond drilling failed to find significant lead-zinc mineralization.

Jan 1, 1949

By M. Salimov, J. Sattarvand

The conventional visualisation method of remote equipment is through the installation of one or more cameras on the machine, and sending a live feed to the operator’s flat display. However, the performance of the teleoperation can be enhanced using better visualisation through virtual reality (VR). This paper presents the process of the design and manufacturing of a robotic platform that will be used in the next phase of the project for a VR-assisted teleoperated excavator. The robot consists of a loading boom and arm arrangement installed on the undercarriage of a CAT300-9D. All hydraulic cylinders are replaced with electric actuators, and crawling motors are substituted by electric motors. The pieces of the boom and the arm, as well as the bucket were designed in Autodesk Inventor, and manufactured from aluminium sheets using a desktop and CNC machine. Parts are joined by pins and welding as needed. An Arduino-based control system is developed for the robot, and motor controllers are used to convert the power commands from the microcontroller to the high-amperage actuators. The control system is capable of communicating with a wireless Play Station controller to operate remotely. The manufactured robotic excavator is planned to be utilised in multiple autonomy research projects.

Sep 1, 2021

In conjunction with steady increases in production levels, long-wall operators have applied greater quantities of ventilating air to control respirable dust and methane gas. As a result, air velocities greater than 7.6 m/s (1500 fpm) have been measured on longwall faces. Operators have expressed concern over the potential entrainment of respirable dust at these high-velocities, especially during shield advance as dust falls from the shield canopy directly into theair stream. Laboratory tests to simulate dust liberation by shield movement were conducted at the Pittsburgh Research Laboratory of NIOSH in a wind tunnel designed to study dust entrainment in high-velocity airstreams. Dust was introduced into the tunnel to determine dust concentration as it relates to entrainment, dilution, air velocity, and particle adhesion. Airborne dust samples were obtained by iso-kinetic sampling using BGI cyclones to quantify respirable dust concentration at the various air velocities. Laboratory tests were con-ducted at velocities ranging from 2.0 to 10.1 m/s (400 to 2000 fpm),and significant differences in airborne respirable dust levels were measured. This research is being conducted to provide fundamental information on the entrainment characteristics of respirable dust at high air velocities, which will subsequently lead to solutions for shield dust control. A discussion of the test procedures and results are presented.

Jan 1, 2004

By P Gunn, M Watts

The general goal of passive acid mine drainage (AMD) treatment is to reduce levels of acidity and metals to acceptable levels. Most treatment systems use either an oxidising or a reducing strategy. In oxidising systems, alkalinity is added along with dissolved oxygen; in reducing systems, dissolved oxygen is removed (if present) and then alkalinity is added. It is recommended that small-scale field trials be conducted as part of the methodology of selecting the best remediation strategy at AMD sites. Following successful field trials at the Sullivan Mine AMD, the Pike River Coal Company (PRCC) has shown foresight by using the same system to treat AMD generated as a result of taking a bulk sample of coal at the Pike River coal field. The system reduced acidity by 100 per cent, iron by 99 per cent, aluminium by 96 per cent, nickel by 95 per cent, manganese by 51 per cent and zinc by 99 per cent. The success of this field trial suggests that a system using a reducing strategy may be appropriate for the Pike River Adit AMD site.

Jan 1, 2005

By V. E. Edlund

As part of a research program for recovering alumina from domestic nonbauxitic resources, the Bureau of Mines investigated a lime-sinter, caustic leach technology for anorthosite. This report discusses the unit operations--feed preparation, sintering, and leaching. Acceptable pellets for the bench-scale sintering studies were prepared from mixtures of minus 200-mesh anorthosite and limestone using water alone as the pelletizing agent. Heating pellets at 1,270° to 1,360° C for periods of 0.5 to 2 hr, followed by a 15-min soaking period at 700° C and cooling to room temperature, produced a sinter that dusted to more than 90 pct minus 65 mesh. The weight ratio of limestone to anorthnsite was critical in producing sinter exhibiting good dusting and leaching characteristics. A ratio of 2.0 was optimum for the bulk samples of anorthosite and limestone used in this research. Leach solutions from lower ratio sinters were unstable; gelation became progressively more severe with higher ratio sinters. Leaching the dusted sinter with 10-pct Na2CO3 at 60° C extracted 85 to 90 pct of the alumina in a product solution containing about 50 g/l A1203. Leach residue in contact with pregnant solution tended to set up as a rigid gel as a result of cementation, comp action, and gelation. The presence of a calcium-sodium zeolite [(Cn,Na2)6?(Al2Si04)12?27-3OH20] in the ungelled residues seemed to be the main difference between gelled and ungelled residues.

Jan 1, 1982

By D. Vogt

A brief summary of the propagation characteristics of rock provides the necessary understanding to design effective radar surveys. Measurements of the electrical properties of the major Bushveld platinum-bearing horizons and their host rocks show that radar is an excellent tool for both short -and longer-range mapping. Experimental work confirms the performance predictions. High frequency, 500 MHz ground-penetrating radar (GPR) is a first-rate tool for mapping features in the hangingwall of the orebody, locally known as a ?reef?, for the purposes of determining hangingwall stability. The triplet chromitites above the UG2 have been clearly mapped, as has the Leader Seam above the UG2. Borehole radar at lower frequencies has been used over longer ranges to map reef elevation. Potholes in the UG2 are clearly distinguished in range and elevation to within metre accuracy. The nature of the slump in the various footwall horizons is also apparent. In future, as GPR is routinely applied, it is likely to become used for other purposes. Borehole radar is being developed to operate at higher frequencies, which will allow it to be deployed from boreholes that are within 5 m of the target horizon. Keywords: GPR, borehole radar, Bushveld Complex, UG2, Merensky, pothole, triplet

Jan 1, 2005

By Peter Bellairs, Anthony Bubb

The Porgera Gold Mine is located at an altitude of 3000m in the central highlands of Papua New Guinea some 600 km Northwest of Port Moresby the capital city. Access to the mine is via a five hour trip on an unsealed road from Mount Hagen the nearest regional centre or 40 minutes via air. The mine operates on a fly in - fly out basis and currently produces ore from both opencut and underground operations with the former providing the bulk of the mill feed. Opencut mining utilises conventional truck / shovel, drill and blast methods on both 10 metre and 14 metre bench heights with the larger benches being restricted to the stripping areas. This paper presents the strategy used and the results of a blast optimisation process in the opencut that was a joint effort between the mine personnel and the explosives manufacturer/supplier.

Jan 1, 1997

By W. L. Chong, Y. Zou

There are many types of Earth Retention Systems (ERS) available in the market where more than one method can be a feasible solution for a project. This paper examines the design and construct process of a project in Dee Why, NSW using a hybrid ERS comprising contiguous piles with jet grout infill. The development comprises a deep basement and mixed-use urban superstructure. The site is located in an area of variable ground conditions, high ground water table and in proximity to existing buildings with multi-level basements. This paper details a comprehensive assessment of the geological conditions and strategies adopted to better understand the effectiveness of the proposed product and to minimise the associated risks of the proposed solution. This involved conducting additional geotechnical investigation, extensive numerical modelling and in-situ monitoring of the movements and the performance of the walls. A monitoring regime consisting of inclinometers, survey points on capping beam and prisms on the neighbouring buildings and roads surrounding shoring wall was implemented. The monitoring results were back-analysed using computer software WALLAP, Plaxis–2D and Plaxis–3D for the post-construction examinations. This paper details the effectiveness and advantages of a hybrid ERS using contiguous piles with jet grout infill.

Nov 1, 2022