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By E Donskoi

In order to develop downstream processing routines for iron ore and to understand the behaviour of the ore during such processing, extensive mineralogical characterisation is required. To determine mineral associations, mineral liberation and grain size distribution, imaging techniques have to be used. There are two main imaging techniques used for the characterisation of iron ore, ie, Optical Image Analysis (OIA) and Scanning Electron Microscopy (SEM). In this article a QEMSCANTM system is used as an example of SEM methodology and results obtained from it are compared against results obtained by the CSIRO ‘Recognition3/Mineral3’ OIA system.Both OIA and QEMSCANTM systems have advantages and drawbacks. Even though the latest QEMSCANTM systems can distinguish between major iron oxides and oxyhydroxides, it is still problematic for QEMSCANTM to distinguish between iron ore minerals very close in oxygen content, eg haematite and hydroheamatite, or between different types of vitreous goethite.QEMSCANTM also can misidentify minerals with close chemical composition, ie haematite as magnetite and vitreous goethite as haematite. In OIA, iron minerals with slight differences in their oxidation or hydration state are more easily and directly recognisable by correlation with their reflectivity. In both methods, the presence of microporosity can result in some misidentification, but in SEM methods misidentifi cations due to microporosity can be critical. Low resolution during QEMSCANTM analysis can significantly affect the textural classifi cation of particle sections.The main conclusion of this study is that, for low iron content ores or tailings, QEMSCANTM can provide much more detailed information on the gangue minerals than OIA. However, for routine characterisation of iron ores with high iron content and containing a variety of iron oxides and oxyhydroxides, OIA is a faster, more cost-effective and more reliable method of iron ore characterisation. A combined approach using both techniques will provide the most detailed understanding of iron ore samples being characterised.

Jul 11, 2011

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

The Harmonious Design on the Beneficiability for the Pt-Pd Ores Containing High MgO Gangue in Yunnan

Sep 13, 2010

The geological features of the destructive plate margins of the southwest Pacific favour the formation of porphyry type deposits. The major controlling factor favouring the formation of gold-rich deposits of this type is a dense crust. This results in shallow intrusion of large magma bodies beneath andesite stratovolcanoes. Where the intrusives have near vertical sides, the comparatively low temperature of transfer of volatiles from the solidifying melt favours the partitioning of gold into bubbles of volatiles. They reduce the viscosity and density of the melt, resulting in the upward movement of a mineralised melt. With the drop of pressure with upward movement the bubbles separate into a two phase mixture, triggering freezing of the mineralised melt and the formation of a gold mineralised stockwork.

Jan 1, 1995

By N Pranoto, E Lawell, T Dean, M Grant

The Goonyella Riverside Mine is located 30 km north of Moranbah in Central Queensland, Australia. Recent mining activities have exposed the north–south striking Kenya and Zimbabwe thrust Faults. These faults vertically offset coal seams by up to 25 m and locally thicken coal packages through imbrication of coal seams. The presence of back-thrusts add to the geotechnical complexity of maintaining highwall stability. The Kenya and Zimbabwe Faults have provided multiple challenges to the mining operation, with an unplanned additional 240 kt of coal tonnes being mined from imbrication of coals seams or from the refinement to local scale geological models. These additional coal tonnes have been either identified during the mining of the coal seam or just prior to overburden removal above the coal seam. These faults can also negatively impacted highwall stability with highwall failures, lowering the overall slope angle for pit designs and increasing stand-off distances for hazardous highwall conditions. Unmanned Aerial Vehicles are used to scan exposed highwalls and enable geological mapping via high-quality 3D images. Measure while drill data from drill and blast rigs can provide local-scale intersections of the faults and coal seams. Mine Geologists utilise these and other data sets to create localised geological models refined position of the fault planes and coal seams. These models are utilised by relevant mine site teams to ensure the safe and efficient mining of coal around these faults.

Mar 22, 2022

By L Lorenzen, H Muller, L Bernard

Australian companies and consultants are becoming ever more involved in projects in African, South American, East European and Middle Eastern countries. However, significant differences in culture and approach to projects sometimes make these projects challenging for reasons that are not purely technical. Often the challenges are rather related to how the project owner and local authorities perceive the reality. These perceptions and sometimes unrealistic expectations regarding project costs and potential outcomes need to be addressed by the æWesternÆ project developer and consultant.This paper will discuss the specific experience of Snowden in studies commissioned by companies from such countries for the development of very large, low-grade gold deposits in some of the most inhospitable areas in the world. The paper will further review similar projects undertaken in other ænew worldÆ countries and compare these to the initial Snowden experience.As the process operating costs of operations in many of these countries are extremely competitive when compared to the typical Australian operating costs, the paper will review the operating costs and the factors which may be pertinent to a large project of this nature, both in the Australian and the ænew worldÆ context. Will Australian-based operations be able to compete in the global gold market when the gold price softens again, as it will do at some stage in the possibly not-so-distant future?CITATION:Muller, H, Lorenzen, L and Bernard, L, 2013. Challenges of developing low-grade deposits in ænew worldÆ countries from a mining consultantÆs perspective, in Proceedings World Gold 2013 , pp 307-314 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

This paper reviews recent advances in geophysical tools for mineral exploration. It does not restrict comments to methods which are usually applied in the tectonically active belt surrounding the Pacific Ocean, where geophysics has often been secondary to geological prospecting (eg visual recognition of surface alteration) and drainage geochemistry; but considers geophysical tools applied to a broader range of both deposits and terrains. For example, the subdued topography of much of Australia and Canada has lent itself to the development and extensive application of airborne methods. In Australia, deep weathering and transported cover have necessitated the use of geophysical methods to not only detect anomalies but also to map and understand basement geology. This same weathering has caused specific problems, particularly for electrical methods, but recent improvements in instrumentation, processing and visualisation have largely overcome them. A great deal of geophysical data is now being collected by government agencies, often from the air, and made readily available to explorers. In several Australian states it is free, often on line, and in almost all cases it is relatively cheap. These regional data sets are often augmented by more detailed local surveys in areas of interest. Although æanomaliesÆ are still important much more is being done with the high quality data which is now available The results are used for geological mapping, to test geological hypotheses, to construct detailed 3D geological models and, together with fluid flow modeling, to predict optimum locations for mineralisation.

Jan 1, 2004

By McKinnon R. L

Laboratory and field work on the use of wetting agents for suppression of colliery dust is described. Although the results were inconclusive they were not discouraging and further investigation is required. The use of certain wetting agents may constitute a healthhazard.INTRODUCTIONCoal dust presents explosion and health hazards to the coal mining industry. The problem of dust suppression is particularly acute where water alone is unsatisfactory for this purpose. The addition of a surface active agent (wetting agent) to the water should enable the dust particles to be more easily wetted and thus more easily prevented from entering and spreading through the mine atmosphere.Investigations into this effect carried out at The University of Sydney mainly under research grants from The Joint Coal Board (Dawson and Hargraves, 1955; Charlton and Curnow, 1957) are summarized, and information on the possible harmful effects of certain wetting agents is given.Twelve local manufacturers and five importers supplied 52 wetting agents in liquid, solid, powder, and paste form.The active material content varied from approximately 10 per cent to 100 per cent and the cost per pound from 8d. to 14/3.LABORATORY TESTINGPossible test methodsThree methods of laboratory testing were considered.1. The standard method for comparing wetting agents is the Draves test, used in the textile industry on cotton...

Jan 1, 1961

By P N. Holtham

Magnetic separation is routinely used in the processing of titaniumminerals, and the efficiency of these operations can be determined bymeasuring the magnetic properties of the process streams. The valuable components in the feed to a titanium minerals plant have specific magnetic susceptibilities ranging from -10-9 m3 kg-1 (zircon) to 10-6 m3 kg-1 (ilmenite). However, in an industrial environment, in which the mineral temperature may range from 20 to 120¦C, it is difficult to measure susceptibilities lower than about 10-7 m3 kg-1. Hence laboratory testing of spot samples from magnetic separators is currently required to obtain accurate performance data. This is an inherently slow process and where feed grades are variable, optimum performance of magnetic separators is generally not achieved.This paper describes the development of an inductance-basedinstrument for measuring very low levels of magnetic susceptibilityon-line. The signal from the instrument can be used for process control purposes to maintain optimum magnetic separator performance.A prototype instrument has been installed in the zircon scavengercircuit in an Australian titanium minerals plant. The circuit consists of a roll magnetic separator treating a feed consisting mainly of monazite and stained zircon. The monazite-rich magnetic fraction is returned to the mine site for disposal, while the non-magnetic fraction is recycled to the zircon wet circuit. Splitter positions in the separator are adjusted when the final zircon product fails to meet specification, or the magnetic fraction contains more than 30 per cent zircon. Weekly composite grain counts show that sub-optimal operation of the magnetic separator results in significant zircon losses into the magnetics fraction.Using the instrument, the zircon content of this stream can now beaccurately determined from the measured magnetic susceptibility,provided a correction for the effect of mineral temperature is applied using the Curie - Weiss relationship.

Jan 1, 2001

The concept of æsustainabilityÆ can largely be defined as development that will not compromise the ælivabilityÆ of the planet for future generations. It has multiple dimensions, such as the triple bottom line û environmental, economic and social. And it also includes temporal (now and the future) and spatial (local and global) aspects that have to be taken into consideration to achieve true sustainability.Energy sustainability might be defined as û having the light turn on when you push the switch. It has, of course many more dimensions than this simplistic definition. Coal in Australia has an important role in keeping our lights on, but has its problems that need to be tackled head on to maintain a role in sustainable development.An overriding issue in terms of sustainability for coal is its major contribution to our greenhouse gas emissions. Whilst we have one of the most effective energy sectors in the developed world, based on well-managed, abundant fossil fuels, our greenhouse gas emissions are one of the highest per GDP in the developed world. We have to reduce our ægreenhouse gas signatureÆ.This paper explores the issues of coal utilisation greenhouse gas emissions as an indicator of the fuelÆs sustainability and the potential lower emissions pathways we will have to follow in a future carbon-constrained world.The technology changes will have significant implications for the minerals industry and it is argued that forward-looking coal/greenhouse emissions strategies need to be developed in alliance with the coal (and energy) sector for the minerals industry to maintain its global competitiveness.

Jan 1, 2004

By S J. Schafrik, Z Agioutantis, E C. Jong, K Luxbacher

Real-time monitoring of mine operating parameters is available at most mines. However, access to these data for an individual operation is typically underutilised by mine managers and technical personnel. Such monitoring systems are typically designed to provide data streams and alarms to a responsible person, but they are not utilised to extract underlying trends or correlate different data groups. Furthermore, multiple monitoring systems are usually implemented at a given site without interconnection between vendors’ systems or connection to any central management, and mine personnel are only exposed to a minimal subset of such data. Thus, it is not easy to analyse and correlate individual data streams and generate information to enhance day-to-day operational decision-making and improve safety and efficiency.This paper addresses the primary challenges associated with centralising data management and effecting greater utilisation of the vast amount of collected data, while at the same time reducing the time and effort required to manage such large data sets. Furthermore, it presents the conceptual design of a database application that can organise, present and analyse data collected by multiple sensors in different environments. The database is designed to operate in a passive manner so that active mine data management systems are not impacted. An example is given where this database is used for managing atmospheric data collected at an underground coalmine operation in the US. These techniques have a universal application and can be incorporated in a wide range of mining and construction projects.CITATION:Agioutantis, Z, Schafrik, S J, Jong, E C, Luxbacher, K and Karmis, M, 2015. A platform for managing and analysing atmospheric data in underground coalmines, in Proceedings Third International Future Mining Conference, pp 3–10 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By A Tawadrous, B Wheeler, D S. Preece, S A. Silling

The two key results of rock blasting are fragmentation and movement of geomaterials. Movement/flow of the blasted rock is often referred to as heave. Moving rock with explosives rather than mechanical equipment can improve mining efficiency. Such is the case with coalmine cast blasting. Controlling and directing rock movement through explosive deck delay timing can greatly improve ore recovery by segregating ore and waste. In both cases, understanding, predicting and controlling heave is an important element of successful blasting.Computer programs for predicting 2D blasting-induced heave have been used in mining for decades, helping to drive the innovation of new and more efficient mining methods, ie cast blasting. The past few years have seen the advent of 3D distinct element modelling of blast-induced heave. This is an important advancement because most blasting situations are three-dimensional in nature, especially when controlling the direction and intensity of rock movement through explosive deck delay timing.This paper documents the first full-scale blasting simulations in 3D with distinct element models that include hundreds of blastholes and in excess of a million particles, made possible with parallel processing. Surface mineral blasting is the focus of this study which treats the effect of blasthole delay timing on ore recovery. Ore waste and dilution resulting from typical row-on-row delay timing will be demonstrated. Also demonstrated will be the ore recovery possible with delay timing designs that significantly enhance ore/waste segregation. This type of high fidelity modelling and the use of electronic detonators makes possible the sculpting of rock blasting muck into separate piles of ore and waste.CITATION:Preece, D S, Tawadrous, A, Silling, S A and Wheeler, B, 2015. Modelling full-scale blast heave with three-dimensional distinct elements and parallel processing, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 127–136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

Due to highly competitive international coal markets, Stockton mine is bound to produce very high quality coals consistently if it is to maintain and expand its market share. The nature of the deposit is such that coals from various source pits are blended in differing proportions to meet the various coal quality specifications of the customer. The complexity arises due to quality variation within the seam both horizontally and vertically and the fact that up to six different products with completely different quality specifications may have to be produced. With increasing demand for this rare product and with CoalCorp eager to meet this demand comes the requirement for computer methods to handle this highly complex problem of both modelling and scheduling.

Jan 1, 1989

By J B. Taylor

Geographic Information Systems (GIS) are being increasingly used by the mineral exploration industry in the search for new ore deposits. A mineral exploration GIS links geological and geophysical data by virtue of their geographic location in a digital map setting. Geological and geophysical data are categorised into a number of themes or layers within a mineral exploration GIS. These layers may include polygonal information such as rock type and tenements, line information such as faults and fold axes, point information such as mines and mineral occurences, and images such as gridded geochemistry and aeromagnetics. A mineral exploration GIS is a powerful tool to help the explorationist comprehend the spatial associations and interrelationships of his/her data. These spatial associations can be integrated with a mineral genesis model, to create a mineral prospectivity map to more effectively target exploration. Arguably a competent geologist who has a good understanding of the genesis of the local ore deposit types and knows their local geology backwards could intuitively derive a mineral prospectivity map. However, in an era of rapid data accumulation from many different disciplines, the ability to assimilate and understand is a huge task for any individual. A mineral exploration GIS enables the explorationist to spend more time analysing data and testing ideas, rather than finding and manipulating data into compatible formats.

Jan 1, 1994

By G Hayes

Ore from the Browns deposit near Batchelor, in the Northern Territory of Australia, is a fine-grained polymetallic sulfide ore hosted in graphitic black shale. Minerals of economic significance are seigenite (Co,Ni)4S3, Galena (PbS) and Chalcopyrite (CuFeS2) with minor Sphalerite (ZnS). Gangue minerals include quartz, carbon and K-feldspar. The grain size is fine, with a significant amount of the seigenite present as Early flotation work determined that a grind size of around 20 microns was required to achieve clean sulfide concentrates. This work recommended oil agglomeration flotation, in which small sulfide minerals were collected, then loosely agglomerated with oil ahead of flotation into a heavily mineralised froth. In the 400 kg/hr prototype plant this froth proved unmanageable. A conventional flotation circuit after grinding to a P80 of 24 microns and using very low flotation pulp densities resulted in an 86 per cent cobalt recovery.The paper analyses further laboratory work which has increased cobalt recovery to 91 per cent by grinding to û250 microns ahead of flash flotation. The real cobalt recovery breakthrough comes from flash flotation of the whole mill discharge rather than the more usual flash flotation of cyclone underflow. Flash flotation tailings are ground to û38 microns and are floated under normal flotation conditions with only the scavenger concentrates being reground to 20 microns.A one tonne per hour prototyping campaign is scheduled to demonstrate the robustness of this circuit.

Jan 1, 2002

THE machine from which the following results were obtained makes one of a row of seven at work in the Junction North, Concentration Mill at Broken Hill, New South Wales. It consists essentially of a belt for dressing purposes, which travels round two 12-in drums situated at either end of a wooden frame. This frame is supported on wooden legs, and the whole is affixed to two iron castings, one on either side of the frame. A to-and-fro motion is obtained from an eccentric shaft, which, together with the stationary end of the supporting legs, is carried by the iron castings. A belt drive to the forward drum provides a constant rate of travel to the dressing belt.The top half of the dressing belt is supported on 3-in rollers spaced about 12-in centres along the frame of the vanner. A fairly thick dressing belt is used, and no trouble whatever is experienced from the formation of gutters between the rollers.These belts are 28 ft 4 in long, 4 ft wide, 3-16 in thick, and are made of two-ply 32-oz duck, with a coating of rubber on either side. The surface available for dressing is about 10 ft 6 in x 3 ft 8 in- ie, about 38'5 square feet. The machine is driven atthe rate of 245 i-in strokes per minute, while the dressing belt travels at 15 feet per minute...

Jan 1, 1909

By E McLean

The decision making check-list and hierarchy of information for process and plant design is generally wide-ranging and complex. The nature of grades, mineralisation and ore types in an ore body, its mine development sequence, and the body of results from metallurgical and physical test work present complex and competing influences on flowsheet development, values for design, equipment selection, plant efficiencies and operating strategy. The challenge is how to manage all these variables, to understand their impacts on performance, and how best to provide a cost-effective plant design and robust process that meets daily/weekly/monthly operating objectives. Throughput, production and grade or product specifications need to be met. The ore body is not average; its range of metallurgical and physical characteristics may be moderately to highly variable. This paper assesses some of the key competing influences and conflicting issues in design and equipment selection, and their effect on production and performance expectations.

Aug 8, 2011

By R L. Brathwaite, S E. Belliss

Linear and semi-circular features were mapped in the volcanic terrain of the southernCoromandel Peninsula, North Island, using JERS-1 synthetic aperture radar (SAR), Landsat-4 Thematic Mapper, and SPOT-2 multispectral satellite data, digital elevation models, and aeromagnetic data. The mapped features typically correspond to recognised physiographic features and are thus a useful aid to mapping the structural trends in the region. Major linear features exhibit a strong N-S to NNE-SSW alignment, and lesser NW-SE and NE-SW trends. All these are superimposed on pervasive, closely spaced, NNE-SSW and NNW-SSE lineaments present over most of the hilly parts of the map area. There are few major E-W aligned features. Some alignment trends correspond to strike directions of veins in the epithermal gold-silver deposits of the region, but none of the known mineralised structures were visible on the remote sensing data.   The volcanic rocks are Late Cenozoic in age and include a variety of rock types: andesite and dacite flows, domes and tuff breccias, rhyolite domes, tuffs and tephra, lacustrine siltstones, and ignimbrites. Mapping of different textures in the SAR image failed to provide additional information on rock types to that derived from the Landsat and SPOT images. A simple discrimination of rock units based on radar texture is apparently prevented by the complex volcanic geology, superimposed hydrothermal alteration, and long period of erosion.

Jan 1, 1994

The difficulty of accurately sampling cyanide gold bullion for valuation is well known, and nothing new or original is claimed in presenting this paper, but it was thought that a record of differences in the composition of bullion bars found here may be of interest to others, and perhaps helpful to those who have to do with theevaluation of cyanide bullion. This investigation was made after reading Mr. Sydney W. Smith's interesting paper on the Liquidation in Molten Alloys.*A method was in use of boring each ingot in two places and mixing the two borings for the sample. More accurate values were obtained, however, when the bullion was sampled in a molten condition immediately before casting into the ingot; the sample being so taken as to preclude oxidation of base metals before solidification of the sample.In all, samples from 32 ingots were assayed, and comparisons made between the existing boring sample and the proposed dip sample. Assays were also made of two other portions of the borings from each ingot, and the results show that in the majority of cases the borings sample assays higher in gold than the dip sample of the same ingot.The largest ingot cast weighs approximately 920 troy ounces, and has the dimensions shown in the attached sketch (Fig. 1). Ingots are cast in 0.1. moulds i in. thick, smoked and heated.METHOD OF TAKING BORING SAMPLES OF BULLION BARSThe bar is cleaned from adhering slag and drilled in two places only, to a depth of i-in., one hole on the top near one end and the other in the bottom at the opposite end of the bar.

Jan 1, 1931

By R Crookes

Mine to Mill optimisation is not a recently developed concept. It is one which is finally gaining greater acceptance in the Australian Mining Industry, possibly as a consequence of the downturn in markets and certainly made possible by the development of tools and techniques to measure and predict performance of mining equipment and milling plants. Fragment size after blasting has a major bearing on the performance of all aspects of mining and a major influence on the economics of the mine and mill. The process to optimise fragmentation consists of identifying the key factors, measuring their sensitivity through a modelling and trialing program and conducting economic evaluations on the changes on both the mine and mill. Management of the Ernest Henry copper-gold mine in NorthernQueensland, Australia, has espoused the Mine-to-Mill concept and isactively pursuing excellence in blasting to drive down the total cost of mining. Ernest Henry has extremely hard, wet and heavily jointed geological conditions, and had high powder factors and a large percentage of oversize material reporting to the crusher or ROMstockpile. A blasting improvement program was undertaken betweenErnest Henry Mining, Thiess Contractors and Orica Explosives tooptimise the ore size distribution, particularly the oversize component, as a step to reducing production costs. Measures of success included bringing the rock breaker back from double shifts to part-time operation and increasing direct dumping into the crusher from 70 per cent to 92 per cent. Tools and technologies to predict and measure the performance ofindividual blasts are needed before it is possible to optimisefragmentation or the downstream processes. These include suchspecialised Orica Explosives tools as SABREX, POWERSIEVE, andPOWERLINE and commercially available drill monitors. As importantare the more common still and video camera, borehole loggers,measuring tapes, surveying equipment such as face profilers, and ahigh-speed camera if possible. There are many tools which can be applied however it is rarely necessary or possible to use all of them due to time constraints and a point of diminishing returns. The critical point is knowing what the true parameters of the blast were compared to design - only then can the predictive tools be effectively utilised. Stage one of the program has seen gradual improvement as theunderstanding grew and practices have been implemented resulting inreduced bridging in the crusher, geological mapping with respective blast designs and the oversize component under control. This paper is about a process approach which links tools and technology to understand the fragmentation drivers and then to optimising the size distribution.The continuous improvement program continues...

Jan 1, 2000