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By Weir D. R, Doyle B. N

The Sherritt Zinc Pressure Leaching Process is based upon the direct pressure leaching of zinc sulphide or lead-zinc bulk sulphide concentrates to produce zinc sulphate in solution and elemental sulphur in the leach residues. The zinc sulphate solution is compatible with conventional purification and electrowinning technology. The pressure leach residues can be treated for the recovery of elemental sulphur, lead and silver. With the conversion of sulphur to the elemental form, zinc pressure leaching allows zinc winning to be independent of sulphuric acid production. Direct pressure leaching of zinc sulphide concentrates was started commercially in October 1980. Continuing research and development studies have defined various pressure leaching configurations for integration with existing roast-leach operations, for grass roots plants, or for plants which are to have the roast-leach section completely replaced. These studies have included the treatment of zinc concentrates from various Australian producers and the development of process flowsheets for potential applications in Australia.

Jan 1, 1989

By Oliver R

The Hamersley Iron ore resources are geologically complex with fluctuations in mineral chemistry. From this resource Hamersley Iron must produce consistently high quality direct shipping products and have the ability to evaluate the effects of changes in demand. In order to achieve these objectives an incremental long term planning technique has been developed. This method reduces the total geological resource statement into a simple, logical sequence of events. A logical sequence of mining increments is defined within individual areas based on a final pit and access system. Increment characteristics are derived manually and from a computer based orebody model. The end product of the technique, an optimum mining schedule, is readily developed from the incremental information. Among its many benefits, this simple technique rapidly provides management with information for policy formulation.

Jan 1, 1979

Rare-earth permanent magnetic roll separators, pioneered by our group a few years ago, have distinctly different operation characteristics compared to prior art electromagnetic separators of various types. Many new applications for dry high-intensity (or better: high-force) magnetic separation have been developed in a short time period. It has also been found that the new generation of separators generally are more efficient with regards to removal of weakly magnetic contaminants in glass and ceramic raw materials with minimum loss of valuable product compared to induced magnetic roll (IMR) separators.The latest development is in the area of production of clean magnetic concentrates at high recoveries. It is likely that the PERMROLLR magnetic separator will replace cross-belt and lift-type magnetic separators as a result of this most recent advance.The paper will review the features of the PERMROLLR magnetic separator in comparison with other types of magnetic separators on the market and give examples on applications.

Jan 1, 1990

The Fiji islands are the world's most ac- cessible Cenozoic remnant arc. They provide occasional subaerial exposures of an arc frag- ment some 750 km long and 80 km wide, or about the size of the NE Japan volcanic arc. The fragment is one part of the former Vitiaz Arc which once connected Fiji to Vanuatu and Tonga. The Fijian portion has the most completely stu- died Tertiary section which contains a history of arc volcanism from the late Eocene to late Miocene (the Early and Mature Arc stages), a rich diversity of subsequent magmatic responses to the most recent episode of arc rifting (Ear- ly Rifting stage), and an example of transition from arc to intraplate volcanism as this rift- ing proceeded (Late Rifting stage). The arc fragment is surrounded by younger backarc ba- sins. The chemical composition of magmas in both the arc and backarc changed with time, but in opposite directions. In the arc, magmas be- came enriched in sialic components from the Early Arc to Early Rifting stages, whereas in the basins the magmas became more similar to mid-ocean ridge basalts (MORBs) with time. In southwest Fiji, the oldest backarc basin has subducted obliquely beneath the remnant arc du- ring the last 3 Ma, resulting in chemically ex- otic calcalkaline volcanism. During the last decade over 150 radiome- tric age measurements and 650 rock analyses, many with trace element and isotopic measure- ments, have been obtained for samples from Fi- ji, Tonga, and the surrounding seafloor (Figs. 1 and 2). These data are summarized, drawing from the publications of Colley and Hindle (1984), Gill et al. (1984), Hawkins and Melchi- or (1985), Kroencke (1984), Malahoff et al. (1984), Scholl et al. (1985) and Whelan et al. (1985), from the specific research papers refe- renced therein, and from the half dozen or so manuscripts currently in preparation by these people and others.

Jan 1, 1987

AXTAT is a computerised system developed by the Western Australian Department of Minerals and Energy in conjunction with the local mining industry for recording and retrieving information about fatalities and work related injuries. Since its inception, the system has gained considerable recognition by consistently demonstrating its usefulness as a tool, not only to the Department, but for the entire industry nationwide. AXTAT has played an important role in the continuous improvement process in management of occupational health and safety in the Western Australian mining industry with gains in both human and financial terms, by regularly providing timely and accurate statistical feedback on fatalities and lost time injuries to industry.

Jan 1, 1996

By R Piper

The Yabulu Nickel Refinery commissioned in 1974, processes lateritic ore via a modified Caron process to produce high quality nickel and cobalt products. The Greenvale orebody provided the sole source of feed to the plant until 1990 and with well-blended mineralogy, it resulted in stable and predictable plant performance, allowing the operating focus to be on reducing energy consumption and increasing ore throughput. This approach provided better economics than pursuing increased reduction efficiency. From 1990, increasing quantities of lateritic ore were imported from Indonesia, Philippines and New Caledonia. This introduced considerable variation in ore blends and instability in plant operation but also provided the opportunity to treat higher grade ore blends which yielded higher reduction efficiencies. Ore reduction is conducted using 12 Herreshoff multiple hearth reduction furnaces, using heavy fuel oil as reductant. The æROASTERÆ Project was approved in November 2000 with the primary objective of improving Nickel reduction efficiency by: Stabilising Roaster Operation via a structured program including focused maintenance efforts, capital equipment upgrades, new process measurements, process re-design and improvements to operating skills and process troubleshooting. A structured technical program including laboratory and plant studies using one plant furnace as a pilot unit to develop improved knowledge of how the reduction process proceeds in the Herreshoff furnace. Armed with this knowledge, optimised process conditions and a reduction process model were developed contributing to a significant demonstrated reduction efficiency improvement. Technical input to the project was provided by QNI with Hatch providing the engineering and project management for the $8.5 M capital work. Execution of the work included extensive consultation with the plant operators and close cooperation between the Hatch project team and QNI operations personnel ensuring installations were completed with minimal production disruption. A strong focus on safety management resulted in a number of brownfields project relevant safety initiatives being implemented resulting in project completion without a serious injury.

Jan 1, 2002

By M Wilkes, C-Q Liu

Microbial oxidation of refractory sulphide ores (particularly gold and copper ores) are well-established techniques that are increasingly employed because of their low capital and operating costs and environmental benefits. CSIRO has established a multidivisional project, the æBioMineral Processing InitiativeÆ, with the goal of generating new and improved high temperature micro-organisms for biological oxidation of these refractory ores. The project is currently focused on the discovery/generation of novel hyperthermophiles for the bioleaching of copper from chalcopyrite. As part of this project we are investigating the practicalities of genetic modification of iron/sulphur oxidising micro-organisms. The molecular biology of iron/sulphur oxidising acidophiles is still in its infancy. This work is aimed at improving our knowledge of vectors, promoters, selectable markers, gene transfer and expression in these organisms. The Acidithiobacillus ferrooxidans genome is currently available and genomics is proceeding at a rate where in the next few years we can expect at least one or two relevant microbial genomes to be sequenced each year. New genes that impart useful characteristics to iron/sulphur oxidising acidophiles will be available from published genomes and the study of newly isolated hyperthermophiles. We need to be in a position to clone and express those genes. This paper will describe the isolation, transfer and expression of thiocyanate hydrolase genes in Escherichia coli and At. ferrooxidans. Most common antibiotics are not effective against iron/sulphur oxidising acidophiles. Also, the use of antibiotics or their resistance markers outside of a laboratory setting would not be appropriate. Resistance to thiocyanate should be a useful selectable marker, without implications for human or animal health. Additionally, thiocyanate resistant iron/sulphur oxidising acidophiles might have application in gold bio-oxidation plants in arid areas where reuse of contaminated tailings water is desirable. The cloning of thiocyanate genes in broad host range plasmids under the control of E. coli and At. ferrooxidans promoters and the expression and phenotypic effects in both species will be described.

Jan 1, 2002

By R E. Gerald II, B Zhang, T Sander, J D. Smith, J Huang, R J. O’Malley, H Tekle

In the steelmaking process, mold fluxes are essential for ensuring thermal insulation, refining, and the efficiency of continuous casting. Real-time understanding of the in-service composition of slags and fluxes are crucial for optimising the steel production process and improving the quality of the final product. An in situ fibre-optic Raman probe that enables the study of the structure, composition, and viscosity of molten slags and fluxes at steelmaking temperatures has been developed and demonstrated both in the lab and in foundry scale experiments. The focus of this study is on the structural, compositional, and property analysis of molten fluxes in a laboratory setting, with the aim of applying this technology for in situ monitoring during industrial production. Raman spectra were successfully collected at various temperatures from 1000°C to 1400°C in real-time and analysed using a deconvolution algorithm to isolate and quantify peaks in the spectra associated with the specific structures of molecular components in molten and solidifying flux. The research successfully combines in situ Raman spectroscopy with high-temperature viscosity data, specifically targeting CaO-CaF-SiO2-Al2O3 based mould flux systems. Specified ratios of the deconvoluted Raman peaks, such as Al-O-Al/Si-O-Si ratio, shows good correlation with the flux chemistry, while the Q3/Q0 peak ratio shows good correlation with viscosity. A ruggedised Raman probe system was also developed and demonstrated in an 80 kg induction furnace. Ultimately, the goal of this work is to demonstrate in situ slag and mould flux analysis in industrial processes, such as in the continuous caster or electric arc furnace (EAF).

Aug 21, 2024

By Cortes JP

In a dynamic environment such as the Star Mountains of Papua New Guinea Geotechnical Engineering for the Ok Tedi Project must be described as both interesting and challenging. To be effective a reasonable sized team of dedicated people is required with occasional supplementation by specialist consultants and an annual review process. Ok Tedi Mining Limited's (OTML) Geotechnical Section has a vision to be recognised as the leading mine-based geotechnical engineering section in PNG and to be world class by any international standards. This paper deals with the organisational and operational duties of the Geotechnical Section at the Ok Tedi Mine. One of our major roles is in the area of safety, and in particular in the early warning of natural and mining induced geological hazards that may affect safety and/or productivity. The major activities in- clude geotechnical inspections (pit, waste dumps, tunnels, re- gional), data collection activities and database management, geotechnical design and control work.

Jan 1, 1997

By P Hollings, J Holliday

Porphyry copper, gold and molybdenum deposits form in subduction-related settings in association with calc-alkalic or alkalic magmatism. Hydrothermal alteration assemblages are zoned, with potassic cores and propylitic haloes overlain by extensive domains of clay alteration and silicification (lithocaps). Copper sulfides, gold and molybdenite typically occur in veins or hydrothermal breccias, and less significantly as wall rock replacements. Epithermal deposits may form above or to the side of porphyry systems, and may be juxtaposed into the core of a porphyry deposit if rapid uplift and exhumation occur through the life of the magmatic-hydrothermal system. Volcanichydrothermal breccia pipes (ædiatremesÆ) commonly form late in the life of a porphyry system. They may contain clasts of porphyry-style mineralisation, and can host significant epithermal gold resources. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Pollard D. M

In the batch phase disengagement test, an organic and an aqueous phase are mixed together for a known period to produce a dispersion which may be either organic continuous (aqueous phase droplets) or aqueous continuous (organic phase droplets). The continuity of the dis- persion will depend upon the method of init- iating the dispersion, the conditions under which the system is operating, such as temper- ature and impeller speed, and the properties of the liquids, such as viscosity, inter- facial tension and solute content. Once the dispersion has been agitated for the required period, the agitator is turned off and the position of the coalescence interface and the sedimentation interface recorded as a function of time. This will produce a plot similar to Figure 1, where the overall dir- ection of travel of the droplets of dispersed phase is away from the sedimentation inter- face and towards the coalescence interface where the droplets coalesce with the homophase.

Jan 1, 1987

The value derived by good mine planning is often underestimated as many mines steer their attention to the more immediate and more easily recognised successes made by the day-to-day operational æbush fireÆ fighting. Similar to machine maintenance, the efforts made to quickly rectify short-term breakdowns are well recognised; whereas the value derived from the work in planning, scheduling and undertaking preventative maintenance is not so obvious or readily quantified. Too often the focus of the business shifts to building and supporting an efficient operations team at the expense of developing a highly experienced team of mine planning practitioners that are well trained with procedures and purpose-built tools to develop optimum mining strategies. A resource has an inherent value based on its quality parameters and its likely mining conditions. How well that value can be unlocked is governed, to a large degree, by the proficiency of the mine planning practitioners, as they, essentially, set the foundation of the mine business and the path along which the mine will operate. The importance of having a well documented and procedural mine planning methodology that integrates both a thorough technical and economic understanding of the resource cannot be over emphasised. The aim of the mine planning process is to develop a robust mine design and production capability which can best cater for future uncertainty whilst providing the best opportunity to maximise cash flow into the business. The planning process must be transparent and auditable, clearly summarising the process steps and assumptions made to arrive at a justifiable and defendable outcome. To provide maximum value to the business, the planning process must be repeatable and scalable to enable easy replication throughout the different mines and projects within an organisation. The diminishing numbers of highly experienced personnel within our industry, coupled with the growing pressure to clearly demonstrate that appropriate due diligence has been exercised, means that well documented and monitored mine planning processes using purposed built and innovative tools need to be developed to ensure optimum outcomes.

Jan 1, 2009

By Sehic OA

One aim of testwork and flowsheet development is to ultimately provide a reliable and flexible plant that is simple to operate and maintain. Testwork can indicate amenability of ores to CIP treatment and provide a basis for process design and economic appraisal. Batch cyanidation and CIP tests are often sufficient for small projects. Continuous multistage test rigs can be operated to simulate plant operation and to provide data for flowsheet optimisation. Operating requirements, gold recoveries and potential problem areas can be anticipated at an early stage with more confidence. Subsequent project development involving decisions on the basic flowsheet, equipment types and general plant arrangements are based on practical considerations and experience. Computer aided process modeling and economic appraisal can be useful in analysing various tradeoffs, firming up the flowsheet and equipment sizes, and in specifying operating targets for the future CIP plant. INTRODUCTION Carbon-in-pulp (CIP) technology which has developed rapidly since 1974 is now accepted as an economically and technically viable process for the efficient recovery of gold. This paper describes testwork and flowsheet development procedures used for CIP evaluation and design.

Jan 1, 1982

By Elliot B. J

Cobalt is principally produced by hydrometallurgical means from the copper-cobalt ores of Zambia and Zaire. In addition cobalt is commonly found in minor quantities in association with nickel and copper-nickel orebodies. Generally the level of cobalt common to these latter orebodies does not warrant separate processing unless the metal price reaches levels last achieved in 1979 and 1980. For pyrometallurgical processing the distribution of cobalt and the factors which affect the distribution of cobalt between matte and slag are not well understood. A limited amount of fundamental research has been completed on cobalt distribution both for simple oxide and matte systems. The paper briefly reviews the relevant literature on theoretical aspects of cobalt distribution between metal and slag and the deportment of cobalt in sulphide smelting circuits. The deportment of cobalt in the Kalgoorlie Nickel Smelter circuit is critically analysed and areas where recovery improvements may be achieved are highlighted.

Jan 1, 1989

By Piga P, Sammarco O

Ventilation and the environmental climate in the Campiano mine is the subject of this re- search. The mine is located in Southern Tuscany (Central Italy), a region where geothermal gra- dients are very high (three times the average gradient of the earth). The research produced interesting indications as to the influence of surface climatic conditions on the environmental parameters inside the mine. A close correlation has been found between dry-bulb temperature and humidity ratio of the air in the mine for dif- ferent metereological conditions and for differ- ent mass flow rate values. Variations in air enthalpy, caused only by the heat exchange with the rock walls during the flowing of the air through the mine, depends on the surface temperature values. Statistical analyses have been used to ex- press air enthalpy variations on surface tempe- ratures, on the variations of the humidity ratio that the air undergoes inside the mine and on the mass flora rate. The application in practice of the results will permit the identification of correct mea- sures to be adopted so that optimal microcli- matic conditions are produced in the mine.

Jan 1, 1986

By P Mackenzie, S Askraba

Pyritic black shales present several challenges to mining operations due to their reactivity. The risk of predetonation of explosives in blastholes, spontaneous combustion of fractured rock and the generation of acid rock drainage must be managed for safety, operational and environmental reasons. At the Mt Tom Price iron ore mine there is a need to differentiate between reactive and non-reactive shale in order to assess risk and make decisions on materials handling. The current approach uses a combination of stratigraphic information and sulfur analysis of blasthole samples. The time taken for sulfur analyses can be a constraining factor on mine production. A new instrument developed by ANSTO Minerals overcomes some of the current limitations on material characterisation. The IOR MeterÖ measures the intrinsic oxidation rate (IOR) of samples of broken rock by circulating air through a sample and monitoring the oxygen concentration over time. The intrinsic oxidation rate is given by the rate at which oxygen is consumed per unit mass of sample, in units of kg(oxygen) kg-1(sample) s-1. Up to eight samples can be measured simultaneously and the turn-around time can be less than 12 hours. Initial trials of the IOR MeterÖ were undertaken at the Mt Tom Price mine in July 2004. The measured IOR of samples from a blasthole pattern spanning different geological layers containing black shale, correlated strongly with the expected reactivity of those layers. The correlation between position in the geological sequence (detailed stratigraphy) and IOR MeterÖ results were much stronger than that between stratigraphy and sulfur content. The new characterisation technique offers the prospect of improving the ability to identify and predict the behaviour of reactive black shales and to differentiate more precisely between different materials. Mine planning, operations, safety and environment all stand to benefit from the success of further trials of the technique.

Jan 1, 2005

By A Tomsett, R Kidd, Z Casley

Bivariate recoverable resource estimation aims at predicting the recovered metal for a secondary variable when a cut-off is applied to a primary variable. The choice of a consistent geostatistical model is advisable to allow a robust estimation from exploration data of the primary and secondary metal recovery functions on a generic selection block (selective mining unit û SMU) within large panels. Ore processing decisions at Lihir Gold LimitedÆs Lihir Gold Mine are based on the gold and sulfur estimates of SMUs from production (grade control) data. The predictive model from exploration data at Lihir is based on the estimation of a recoverable resource for gold by Uniform Conditioning (UC), with an estimate of the sulfur grade being provided by Ordinary Kriging of panels. While univariate UC is adapted to the diffusive nature of the gold mineralisation (Ladolam orebody) at Lihir, the independent estimation of sulfur, through ordinary kriging, fails to capture the potential spatial correlation that exists between gold and sulfur mineralisation. This paper presents a practical implementation of bivariate UC, which better represents in the resource model the spatial correlation between gold and sulfur. Incremental economic gains through improved definition of material categories and scheduling are investigated, and the particular impact on the process of geological interpretation and domaining is emphasised.

Jan 1, 2009

By Botz R. W

Macroscopic and microscopic studies of the outburst-prone Gemini Coal (Bowen Basin) showed that outbursts were associated with a localized inertinite-rich ply. Previous studies of the Gemini Coal had shown a general relationship between desorption rate, regarded as a good measure of outburst proneness, and inertinite content of coal samples.Desorption rates increased with increasing inertinite content and were highest for inertodetrinite-rich samples. These results suggest that inertinite content and composition play a significant role in outbursting and may be useful in identifying outburst-prone coals, which could be confirmed by desorption measurements.Consequently outburst-prone areas in the Upper Permian coal measures ofthe Sydney, Gunnedah and Bowen Basins have been defined using a combination ofthe parameters, inertinite content, depth ofcover and coal rank. In the Upper Permian, inertinite-rich coals are confined mainly to the top of the coal measures, except in the Sydney and Gunnedah Basins where an inertinite-rich interval (Bayswater Coal and correlatives) is also present towards the base of these measures. Only a small area ofthe central Sydney Basin, butmuch ofthe north-eastern and north-central part of the exposed Bowen Basin is considered outburst prone on the basis of these parameters.The most outburst-prone inertodetrinite-rich lithologies have a patchy and unpredictable distribution in the top of the Upper Permian coal measures. They can be defined only by sampling and petrographic analysis at the subsection level.

Jan 1, 1986

By Hll J. K, Zhang Y. G

The wear mechanisms of impregnated diamond drill bit matrices are complex and believed to be the key point in solving drill bit self-sharpening problems. A method has been developed to find the change in c,, the wear rate of matrices having different fracture toughness K_ at the increment of drill pressure P. The worn surfaces of specimens were placed under a scanning electron microscope to examine the wear patterns and wear mechanisms at different pressures, and were compared with the worn surface of a practical drill bit. A model is proposed that within a wide range of pressures there exist two different wear mechanisms and three wear regions for cemented car- bide matrix materials. In region one (linear region), at low pressure, the major wear mechanism is plastic deformation in which the preferential wear of the binder phase of the matrix results in the loss of WC, tung- sten carbide particles. Wear rate is controlled by hardness, H as Archard's formula predicts. Wear enters region two and three (non-linear region) simultaneously as pressure is being increased. Consequently, wear transfers to fracture mechanism in which micro-fracture occurs at the root of wear grooves and the material is removed mainly in piece and mass. It has been shown fracture toughness K,, plays a more important role than hard- ness H. It is concluded that for a specific drilling condition, the pressure on the matrix should be carefully controlled and a balance between hard- ness and toughness of the material is essential for a steady drilling Condition.

Jan 1, 1989

Three major and two minor uranium deposits 'have been worked by open out mining since the discovery of ,the Rum Jungle field in 1949. Total production has been about 9679000 tons of uranium ore at 7;39 lb U308/ton and 4029000 tons of copper-uranium ore at 6.27 lb U308/ton and 2.7% Cu, with significant tonnages of base'metal ores. The deposits occur in or near black pyritic slates of the Lower Proterozoic Golden Dyke Formation, near the contact with the under- lying Coomalie Dolomite. The mineralization is probably younger than the grahite complexes in the area, and a structural-stratigraphic control of ore deposition is used as a basis for uranium exploration.\

Jan 1, 1968