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Study on Iron Ore Sintering with High Proportion of Specularite Concentrates Specularite iron ores have poor hydrophilicity and ballability as well as bad high-temperature reactivity, which restricts the large-scale application in the sinter and pellet production. In order to make the best use of the specularite concentrates, a novel process of Composite Agglomeration Process (CAP) is applied in this research. By the CAP, the percentage of specularite concentrates in the sinter mixture is increased to no less than 40 per cent as well as the coke breeze dosage is reduced by 0.3 per cent~0.6 per cent. Moreover, all the sintering indexes are obviously improved compared with the traditional sintering process. Researches on the metallurgical performances shows the finished composite agglomerates are high-quality burdens for blast furnaces. This investigation can provide an effective route to utilize the inferior specularite concentrates in the sintering.

Sep 13, 2010

By B Watson

The ConSep ACACIA Reactor is a device, which utilises a high intensity cyanidation process to achieve very high, usually near total, recovery of gold from gravity concentrates. The process utilises a fluidised bed and a chemical oxidant to enhance the gold dissolution kinetics to the point where the bulk of the dissolution occurs in a few hours. For convenience and security, most plants operate a 24-hour turn around. The product from the process is in the form of cathode gold ready for smelting by traditional means. The ConSep ACACIA Reactor performs a two-fold role. Firstly it increases gravity gold production, leading to a decreased CIP feed grade. Secondly, it removes slow leaching components from the plant leaching circuit. This two fold benefit leads to the following efficiencies: enhancement of the dissolution kinetics; enhancement of the adsorption kinetics; reduction of the gold load reporting to the carbon; a significant reduction of the ægold in circuitÆ lockup; and removal of slow leaching entities which can also result in a lowering of the required cyanide concentrations in the leaching circuit and a subsequent reduction in overall cyanide consumption. The above benefits are discussed in this paper, with a particular focus on the ConSep ACACIA ReactorÆs role in removing slow leaching components, with data generated over a 21-month period. Improvement in overall plant recovery via removal of slow leaching gold species is achieved in two ways. Firstly, some of the slow leaching entities, successfully leached under intensive cyanidation, are not always fully leached under plant conditions. This results in a lowering of the solid tailing. Secondly, the faster leaching kinetics achieved in the plant as a result of the removal of slow leaching entities results in faster and more complete adsorption of the dissolved gold onto activated carbon. This results in a lowering of the solution tailings. The construction and operation of the ConSep ACACIA Reactor is simple. Apart from the reactor body, which is a proprietary design, all components of the system are æoff the shelfÆ or specific to the siteÆs requirements. In operation of the fully automated version, a PLC controls a series of valves and pumps but except for a daily changeover process the only operating component for the bulk of the time is a relatively small solution pump. The process can be totally automated giving the security of a æhands freeÆ concentrate handling process up to the point where the product is presented as cathode gold. The ConSep ACACIA Reactor was developed by Anglogold Australia (formerly Acacia Resources) for Union ReefÆs Gold Plant and has been in production since February 1999. It has proven to be a low cost, high recovery, mechanically reliable method for the processing of gold concentrates. Such has been the success of the plant, as of June 2003 there are eighteen full installations of the processing plant installed at mines owned and/or managed by Anglogold, Newmont, Placer Dome, Independence (formerly Lonrho), Sons of Gwalia and Harmony.

Jan 1, 2003

The Framework Convention on Climate Change (FCCC) places serious obligations on New Zealand as a signatory nation. This paper examines the nature of the FCCC, New Zealand 's proposed policy response, and the.implications for the minerals industry.

Jan 1, 1994

By R Shaw, M Hidding

The design of primary sample cutters for high-capacity conveyors is critical to achieving a correct sample, both in collecting the sample and ensuring smooth sample discharge flow. Modelling usually occurs at the design stage and requires extensive experience to achieve the correct result. However, it is difficult to confirm the effectiveness of the cutter design until after installation. Even with high-speed video, confirmation of complete sample capture is difficult, especially if the material characteristics change over time. Recent investigation using discrete element method (DEM) simulation to model the flow of the ore into the cutter and observe how it interacts with the cutter has revealed some interesting design requirements not observed in the past. By including DEM modelling, the correct design and optimisation of the cutter can be more accurately determined prior to commissioning.CITATION:Hidding, M and Shaw, R, 2017. Modelling ore flow in the design of high-capacity sample cutters, in Proceedings Eighth World Conference on Sampling and Blending , pp 145–150 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

Based on relative CO2, N2, and 3He contents, geothermal systems of the Taupo Volcanic Zone, TVZ, can be subdivided into two major groups: arc-type systems, associated with andesitic magmatism along the eastern boundary of the TVZ, and rift-type systems over its western parts. The highly increased N2/3He, CO2/3He and CO2/Cl ratios of the former are ascribed to entrainment of large proportions of volatiles of subducted, marine sedimentary origin. The largely rhyolitic, rift-type magmas are assumed to have formed from volatile-depleted, residual melts. Correlations of Cl and CO2 with heat contents suggest that formation of the two types of source magmas involves mixing of two end member components: a low-volatile melt with a heat/Cl ratio of 25 Ml/mol (0.7 MJ/g), and a low Cl vapor with a heat/CO2 ratio of 5 Ml/mol. On the basis of these values, the heat associated with andesitic magmas is found to be carried in close to equal parts by both vapor and melt; for the rhyolitic melts the proportion contributed from the vapor is only about 2%. The heat/He ratios of the rhyolitic source magmas for the rift-type geothermal discharges from the TVZ of 0.12¦0.05 Ml/pmol is within the range of 0.05 to 0.2 Ml/pmol of the upper mantle. The higher heat/3He ratios for the arc-related magmas of 0.4¦0.2 Ml/pmol are likely to be due to the high proportions of heat carried in the form of a separate, low 3He vapor phase derived largely from subducted sediments.

Jan 1, 1995

Role of Bubbles in the Action of Flotation Agents

Sep 13, 2010

Validation of the JKMRC Rotary Breakage Tester (JKRBT) Ore Breakage Characterisation Device

Sep 13, 2010

By A Kemp, I Taylor, S C. Lamoureux

Detailed landform designs were completed for six (integrated) iron ore waste rock dumps at a Western Australian iron ore mine site to meet closure objectives and to optimise material movements for closure. The designs were based on specific physical and geochemical properties of waste material and the design was undertaken to enhance long-term stability of the dumps and optimise material movements, and therefore minimise closure cost. Construction of the re-shaped waste rock dumps have been completed. Following construction, surface material characteristics were found to deviate from those used in the design assessment. Materials present at surface following re-shaping were generally finer textured than those sampled for modelling. It is anticipated that the embankment slopes may experience increased rates of surface erosion compared to the rates predicted from modelling and used in design. The finer textured material is thought to be generated from exposing finer material that has migrated into the coarser matrix over time or that was not present in the sampled top surface of the landforms. This is due to armouring processes over time and this phenomenon is likely to recur following further wet seasons. The majority of the waste materials present in the waste rock dumps were subgrade banded iron formations (BIF) and chert, which are generally competent and geochemically inert. Some waste material was known to have an elevated risk of erosion but present in relatively small quantities. The presence of a large number of dolerite dyke swarms indicates appreciable volumes of dolerite were produced as waste from the pits. This material has an elevated risk of being highly erodible/dispersive. Clays and shales are also likely to be present in the dumps and are considered to be less competent material (relative to the BIF/chert). This paper presents the process from upfront materials assessment through detailed design to construction of the rehabilitated waste rock dumps, and post-construction sampling and testing to validate model findings.CITATION:Kemp, A, Taylor, I and Lamoureux, S C, 2017. Design to closure – construction of detailed rehabilitation designed iron ore waste rock dumps based on upfront site specific assessment, in Proceedings Iron Ore 2017, pp 353–358 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By B Rosemberg, F Lemos, A J. B Dutra

The chemistry of cyanide solutions is complex, this complexity being responsible for the ability to act as complex-forming agents in metal dissolution processes, among them gold and silver. Such ionic species are used in hydrometallurgical processes, in particular in gold extraction and electro-plating. Due to the high toxicity of cyanide, the discard of effluent from processes and/or industries demands rigorous treatment so as to minimise its concentration. Among the conventional chemical treatment of such effluents one can mention SO2/air; biological degradation; oxidation by using hydrogen peroxide; oxidation by sodium hypochlorite, etc. However, the electrolytic recycling process is also promising for cyanide recovery and offers the possibility of recycling it to the aforementioned industrial processes. Such a process does not use additional chemicals but enables direct re-utilisation to the main process aiming at adjusting the cyanide concentration.

Jan 1, 2002

By D David

The majority of SAG and ball mill design methodologies are applied using a single design value for mill selection, such as the 80th percentile ball mill work index or SMC value. Inherent in the selection of this design value is a desire for the mill to accommodate unfavourable, but not absolute worst case, feed conditions. It has been observed in numerous “post-mortems” of unsuccessful designs and also in many optimisation studies, that the selection of the design value has been poor. Statistical analysis of testwork data sets shows that inherent variability in the data can, by itself, lead to design errors. Metallurgical testing is an attempt to measure the characteristics of millions of tonnes of ore using only a few kilograms of sample. In this paper some realistic but synthetic test work data sets are used to explore old and new methods of defining the design envelope and subsequently selecting a reliable point. The aim of the paper is to provide practitioners with tools that reveal the adequacy (or otherwise) of metallurgical test programs intended to support various levels of project design. It also provide guidance as to how it is possible to statistically justify a comparatively high design point in the absence of adequate test data.CITATION:David, D, 2015. Measuring and taking notice of orebody variability – an essential ingredient for reliable plant design, in Proceedings MetPlant 2015, pp 10–26 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By R H. Sibson

The gold province of Otago occupies an area of upwarped basement, the Otago Schist, comprising predominantly quartzofeldspathic and volcanogenic metasediments. This assemblage is the product of collisional tectonic deformation and associated metamorphism, mainly to lower greenschist facies, during the Rangitata Orogeny (200-100 Ma). Historically this region has produced 240 tonnes of gold, 4% (10 t.) of which was from the mining of Cretaceous goldquartz mineralised vein systems. Auriferous vein systems in the Otago Schist are mainly hosted within NW trending normal fault-fracture arrays, however NW trending reverse fault-hosted vein systems also occur. We propose that the Late Cretaceous-mid Tertiary Otago Schist structure represents a regional anticlinorium containing flexural folds of at least two wavelengths. The anticlinorium structure has been quantified by determining variations in angular discordance between schistosity and the Otago Peneplain, a Late Cretaceous-mid Tertiary erosion surface covering most of the Otago district. A structural model for the evolution of the post-collisional anticlinorium requires the cooling surficial zone (carapace) of a retrograding metamorphic belt to behave as an elastic lid. Erosion of topographic load on the carapace drove isostatic uplift, which was greatest in the tectonically thickened core of the orogen. In this way differential uplift produced flexural deformation in the elastic carapace, expressed as a large scale arching of the orogenic belt. Flexure created tangential longitudinal strains in the outer-arc, leading to extension and the formation of mineralised normal faults. These structures are separated by a neutral surface from shortening and associated mineralised reverse faults in the inner-arc. Our structural model predicts that the distribution of auriferous lodes should be localised about zones of maximum flexural curvature, where the tangential longitudinal strains are highest. As a result, NW-SE hinge regions separating schistosity dip domains in the Otago gold province may have new found significance as potential exploration targets.

Jan 1, 1995

By P Lindsay, J B. Hughes

Underground and opencast coal mining has been ongoing since 1896 on the Stockton Plateau, West Coast, New Zealand. Acid Rock Drainage (ARD) from historic and current mine workings has had an adverse environmental impact on the surrounding aquatic environment. The two main catchments affected by ARD are those of the Mangatini and St Patrick streams. These catchments flow into the Lower Ngakawau River, which holds high amenity value for the local community. Water quality targets set by Solid Energy for 2010 in the Ngakawau River include increased pH and clarity and a decrease in certain dissolved metals.   At-source ARD minimisation options are the first stage in mitigating the effects of mining acid forming rocks and reducing acid loads in the Mangatini and St Patrick stream catchments. ARD minimisation techniques reduce the quantity of acidity generated and thus reduces the treatment required. Treatment will be required for many years at Stockton due to current and historical acid formation. This paper looks at the treatment options that Solid Energy has been investigating including limestone leach beds, engineered wetlands, oxic limestone drains, and limestone dosing of catchment drainage. Particular focus is given to fine limestone dosing of the Mangatini stream and subsequent water quality improvements.

Jan 1, 2007

By J Zhou, D M. Hunter, S M. Iveson, K P. Galvin

The recovery and concentration of ultra-fine iron ore can provide significant economic benefits. Presently, there are limited options available given the low settling rates achieved by conventional gravity separation and the relatively poor performance of reverse flotation. The Reflux Classifier is a new water-based gravity separation technology that consists of a set of parallel inclined channels positioned above a vertical fluidised section. This arrangement promotes a powerful throughput advantage compared to conventional fluidisation and a highly selective hydrodynamic basis for achieving sharp separations. A high shear rate develops within the inclined channels, which generates sufficient hydrodynamic lift to convey the lower-density particles (even if they are relatively coarse) to overflow while retaining the high-density particles (even those that are ultra-fine) for discharge to the underflow. The technology has previously been used around the world on particle sizes in excess of 0.1 mm. The present work, however, is concerned with density-based separations down to much finer particle sizes approaching 0.01 mm.A major advantage of the Reflux Classifier technology is the achievement of simultaneous gravity separation and desliming via a single-stage separation. A series of continuous experiments was conducted using an iron ore feed with head grade of 35 wt per cent FeT and nominal top size of 0.106 mm, with 59 wt per cent being below 0.038 mm in size. At a low throughput of 1.5 t/(m2 h), the Reflux Classifier produced high-grade products at a high recovery. For the entire feed, grades of 66.1 wt per cent FeT with Fe recoveries of 80 per cent were achieved in a single-stage separation. Within the 0.020–0.038 mm size fraction, grades of 68.8 per cent were achieved with iron recoveries of 94.7 per cent. Excellent recoveries of up to 57.0 per cent were achieved for the -0.020 mm size fraction. The ability of the inclined channels to retain the fine dense material further enhances the effectiveness of the Reflux Classifier by creating an autogenous dense medium effect within the vertical section. This helps to elevate large gangue particles up into the overflow.CITATION:Hunter, D M, Zhou, J, Iveson, S M and Galvin, K P, 2015. Gravity separation of ultra-fine iron ore in the reflux classifier, in Proceedings Iron Ore 2015, pp 143–148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

In North-West Nelson the Riwaka Complex, a linear basic intrusive complex, is exposed for approximately 45 km. Some 500 km south, across the Alpine Fault, a linear zone of similar but less well known basic intrusives that may be correlatives of the Riwaka Complex is exposed discontinuously for about 80 km. The Complex was emplaced at several centres along a major tensional fracture zone that developed in upper Carboniferous to Lower Permian time. This fracture zone probably formed in response to the development of a west dipping subduction zone that gave rise to the Permian volcanic arcs in east Nelson and western Southland. The Riwaka Complex contains three rock suites. The Fractionation Suite, characterized by cyclic mineral layering and small scale cumulus banding is the largest and is divided into the Ultramafic, Hornblende and Plagioclase Series, each of which is subdivided into several units. The Cumulus Gabbros represent a restricted but important suite of unusual composition, while the third suite is the late phase Diorite Suite. Except in the lower units of the Ultramafic Series sulfide mineralisation is widespread. Pyrrhotite is the dominant sulfide with lesser chalcopyrite pentlandite and pyrite. Four significant zones of sulfide accumulation are recognised and discussed in some detail. Evidence suggests that the primary magma from which the Riwaka Complex was derived was sulfur deficient. It is concluded that the sulfur content of the Riwaka Complex was derived from assimilation of sulfur rich wall rocks during intrusive processes.

Jan 1, 1980

The outlook for suppliers of energy to the expanding economies of the Pacific Basin region is essentially positive, but particularly for exporters of high quality steam coal. This paper argues that economic growth in the Pacific Basin region has exceeded world economic growth for some years and that this will continue to be the case for the next decade at least. It looks briefly at the link between economic growth and energy demand and at the relationship between energy demand and the demand for electricity. Changing preferences in fuel mix for electrical generation in the region are noted and tentative forecasts made about variations in this mix. The pros and cons of various forms of fuel used to generate electricity are considered from the point of view of the consumer. Having concluded that steaming coal in particular is likely to become even more important as a generator of base load electricity, the paper looks at the opportunities this presents for exporters such as Australia, and touches on some factors that could prevent development of those opportunities. This paper will concentrate on electrical energy. For the purposes of this paper, the Pacific Basin refers essentially to Australia, New Zealand and the Asian countries bordering the Western Pacific. As a supplier, Siberia is not included because, although it has great potential, it is thought that problems of climate, infrastructure and political restructuring will delay the realisation of that potential until the next century. Although it deals with the Pacific Basin region, where many countries are industrialising rapidly from a predominantly agricultural base, it looks at the experience of mature industrial DECD economies where their experiences seem relevant.

Jan 1, 1990

Well designed and maintained haul roads are the key to minimising truck haulage on-road hazards and costs, as well as increasing productivity. However, practically designing and managing a haul road for optimal performance is often diff cult to achieve. Poorly designed and built roads exhibit high rolling resistance - a one per cent increase in road rolling resistance can typically reduce speed on ramp by as much as ten per cent - and on the f at by up to 26 per cent. In the current economic climates, investment and operating decisions come under scrutiny. In the long run, this scrutiny returns improved efficiencies and leaner, healthier operations. The focus of this evolving evaluation process should and will certainly fall on haulage operations - simply by virtue of their contribution to overall cost of operations - often in excess of 50 per cent of total costs for deep open-pit mines. Whilst the end result - improved efficiency and reduced cost per ton hauled - is not in itself problematic, it is the route, or process followed to achieve these savings that needs to be carefully managed. We can be guided on this journey by our understanding of how a road is designed, and, critically, the interplay between a good design and safe, cost efficient haulage.This paper brief y summarises the evolution of mine haul road design, from the seminal USBM work of Kaufman and Ault in 1977, through to current geometric, structural, functional and maintenance management design components. These augmented design and management guidelines have been developed over the past decade, both in response to the requirements of mine operators for more safe and efficient haulage systems, and the truck manufacturers' requirements for a more predictable and controlled operating environment. These developments have been paralleled by the need to minimise haulage hazards, both from a health and safety perspective. Generally, both objectives have been achieved, but with some specific areas of design and operation still presenting ongoing potential health and safety hazards.The paper then summarises current design guidelines for these safety-critical issues, both from a road-design 'best-practice' and road management perspectives. Implementation of the approach is seen as a basis for reducing the potential of an under-designed mine road to lead to health and safety defects and secondly as a means of giving haul road safety and performance issues greater prominence in the minds of the road-user, operator, mine planner and designer alike.

Dec 6, 2010

Some Otago quartz veins display spectacular open-space filling textures indicative of shallow formation. Fluid inclusions in some such veins show that fluid immiscibility occured before or during mineral deposition. This immiscibility or 'boiling' occured at depths ranging from about 3 km to within as little as about 100 metres of the paleo-surface. Temperatures of mineralization range from 190 - 250¦C. Metals deposited in these veins include: Au(+Ag), Hg, Sb and As. Hydrothermal alteration is confined to minor silicifation of immediate wall-rock schist, less than about two metres from the veins. These veins have some similarities to classical epithermal systems elsewhere in the world, although wall-rock alteration is much less developed in Otago. From analogy to these classical epithermal systems, it is speculated that gold mineralisation may be found beneath Otago stibnite and cinnabar localities.

Jan 1, 1987

By R Aseervatham

The fast tracked mine development strategy attempts to blend feasibility studies and engineering/commissioning functions into a streamlined process. In this compressed process, environmental issues are difficult to control with respect to the optimisation of operational environmental performance. This paper presents a standard mine development process with specific focus on environmental issues, and contrasts this against Rio TintoÆs recent fast track experiences on the Hail Creek project (Australia), the Baranj project (India) and the Gokwe North project (Zimbabwe).

Jan 1, 1999

By S R. La Brooy, T Giraudo, I C. Ritchie

The treatment plant at the Macraes Gold Project in New Zealand processes a carbonaceous, refractory sulphide gold ore. Since its commissioning in 1990, there has been a programme of continuous improvement of the plant, leading to higher recovery, increased throughput and low operating costs. During this time, a number of processes for treating both, or either, the preg-robbing carbonaceous fraction of the ore and the refractory sulfide fraction have been evaluated, trialed and utilised. The latest phase involves the installation by Minproc of plant utilising Newmont Gold's Pressure Oxidation Technology, a process which is anticipated to mitigate both problem factors when commissioned in 1999.

Jan 1, 1998

By Associates

The headwaters of Skippers Creek and the Shotover River are reputed to be among the richest alluvial gold catchments in the world. This alluvial gold has no doubt been derived from reef systems similar to, and associated with, the Bullendale lodes. Physiographically the prospect covers steep ridges and deeply incised gullies between the Richardson Mountains in the west and the Harris Mountains in the east. Vegetation is mainly tussock with bush either side of Murdochs Creek. Access to the area is by metalled road to Skippers and then by 4WD track to Bullendale. Alternatively the prospect area can be reached by helicopter from Queenstown in around ten minutes.

Jan 1, 1992