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By W B. Edgar, S C. Dominy

High-nugget effect vein-gold systems are generally considered to be one of the most challenging of deposit types to evaluate and exploit. To potential investors and mining companies, they are viewed as high risk because of the associated uncertainties in the grade estimate and general paucity of Ore Reserves at production start-up. However, despite the well-known risks, these deposits often have a grade upside that makes them potentially attractive. The reporting of resource grade is of importance and perhaps even more so is the reporting of the associated uncertainty attached to the grade estimate. The use of the grade estimate supported by a grade range is recommended to achieve more complete and useful disclosure. The definition of the grade range can be somewhat subjective, ranging from opinion based estimates through to data-based estimates and geostatistical conditional simulation. Whichever method used, the over-riding issue must be the provision of enough data of appropriate quality and full disclosure to the public of relevant uncertainties.CITATION:Dominy, S C and Edgar, W B, 2012. Approaches to reporting grade uncertainty in high-nugget gold vein projects, in Proceedings Project Evaluation 2012 , pp 95-108 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012

Blasthole cone samples are used for grade control in most of the iron ore mines of the Pilbara of Western Australia. This method of sampling is straightforward when the target sampling interval matches the mining bench height but is problematic when the blasted bench is 'flitch' mined in two or more passes. Crucially, the sampler needs to decide which part of the blast cone represents the upper and lower flitches to be mined. This sampling selection decision is usually made by assuming a certain proportion represents the subdrill component of a sampling face in a blasthole cone and the two flitches are split equally from the remaining portion. In this study of a West Australian channel iron deposit, sampling experiments were carried out to determine the actual proportions of a sampling face in a blasthole cone by spray painting the blast cones at flitch and subdrill boundaries during the drilling process. Measurements were then taken to assess the differences between assumed sampling face proportions and actual proportions. A set of paired samples was also collected from a number of blastholes with one set using the assumed proportions of each flitch for each sample, while the other set sampled the actual proportions, which were identified from the cone painting process.

Mar 1, 2010

Various methods and software have been trialled for simulation of Au grades at Boddington Mine. This covers in-house and public software as well as sequential and turning bands methods. The diversity of options was further expanded with comparison of point and direct block simulation. Some difficulties were encountered in incorporating high-grade restrictions. Altering parameters or software can make very significant differences and give results varying from estimations. This paper details a new simulation run with validation and tests for local calibration (or progressive correction) of the simulations to the estimations, focusing on reproduction of statistics. This approach brings to the forefront the question æwhat is the purpose of the simulations?Æ Results and some ideas for future applications at Boddington are summarised.

Sep 26, 2011

By K Faure

At Sams Creek a gold-bearing, peralkaline granite pophyry dyke intrudes Ordovician-Silurian metapelite and quartzite. The granite porphyry dyke has a thickness of up to 40 m, extends discontinuously for about 8 km, and intrudes thin lamprophyre dykes along its contacts. The granite dyke and gold-bearing sulphide and quartz-siderite veins within it have been deformed and recrystallised during several phases of folding, the youngest of which is Early Cretaceous.   The unaltered granite porphyry is composed of phenocrysts of perthite, arfvedsonite, aegerine and quartz in a groundmass of the same minerals, with accessory ilmenite, rutile and fluorite. K-Ar dates of amphibole from the granite gave ages of 226 and 246 Ma, but these ages may be a minimum due to resetting during the thermal and deformation events that have affected the area. Unpublished Ar-Ar data on amphibole from the granite show disturbed spectra with high temperature steps around 300-315 Ma, which is consistent with the age of A-type granites in the Buller region. Further age dating of primary and hydrothermal minerals in the granite is continuing. At least three stages of hydrothermal alteration have been identified in the granite. Stage I alteration is characterised by high fO2 magnetite-siderite ¦ biotite, which is cut by thin quartz-pyrite veinlets (Stage II). These are cut by Stage III sulphide, quartz and siderite veins, and pervasive silicification represented by quartz-perthite-albite-rutile ¦ pyrite-siderite-sericite assemblages overprints the earlier alteration stages. Lamprophyre is altered to a siderite-chlorite-sericite assemblage. Stage III sulphide veins are composed of arsenopyrite + pyrite ¦ gold ¦ galena ¦ sphalerite ¦ chalcopyrite ¦ pyrrhotite ¦ graphite, deposited by low fO2 H2S fluids. The gold contains 18-30 wt% Ag and up to 1 wt% Bi. Temperature of vein formation was estimated from vein quartz fluid inclusion homogenisation temperatures (Th 260-355oC, average 330oC), arsenopyrite-sphalerite thermometry (310-365oC) and quartz-albite stable isotope thermometry (340oC). The altered granite and the veins have been deformed, and recrystallised and competent sulphide minerals are fractured and brecciated. Alteration and mineralisation are confined to the granite porphyry and adjacent lamprophyre.

Jan 1, 2004

By J Rutter, E Amini, D La Rosa, N Beaton, M Scott, F Faramarz, L Keeney

Anglo American’s Los Bronces copper mine in Chile has been conducting detailed assessments investigating value adding options for their asset. The mine has conducted several detailed Mine-to- Mill and Grade Engineering studies to investigate increased throughput and head grade and to quantifying the impact of these approaches across the life of mine. CRC ORE has two key technologies namely Grade Engineering and the Integrated Extraction Simulator. These two technology suites have been combined to understand the technological landscape and associated value drivers suitable for application at Los Bronces. Detailed ore characterisation test work was conducted to:  measure and spatially model the propensity of ores to naturally deport and  develop customised blast models for Mine-to-Mill and Grade Engineering evaluation The outputs of this work were utilised to develop a block model populated with a range on new Grade Engineering and blasting parameters suitable for scenario analysis. To facilitate scenario analysis a high-fidelity value chain model of the Los Bronces operation from blasting to concentrate production was built in IES. IES was combined with sophisticated analytical tools such as Neural Networks to develop and reconcile a fully integrated value chain. The value chain model made it possible to simulate in IES all available blocks in the block model to predict throughput and grade changes for different strategic scenarios. The scenario analysis was run across 24 strategic combinations of Mine-to-Mill and Grade Engineering and comprised several million simulations. The scenarios investigated each technology independently and jointly to provide an attributed block model that can feed forward into technoeconomic modelling to determine optimal execution strategies for the mine. This paper presents the first published study combining Grade Engineering and IES to provide mass simulation capability to investigate strategic options for a mining asset.

Nov 10, 2020

By M Francoeur

Oct 12, 2022

By R Hargreaves, C Morley

The authors often see problems on mine sites that are due to insufficient feedback between technical discipline silos as the realities on the ground fail to inform the models and plans used to drive resource exploitation. Resource modelling, reserve definition, life-of-mine planning, short-term mine planning and scheduling, mine operations and beneficiation operations are all processes that inform each other, but in many instances feedback between these processes occurs in an ad hoc way and only after problems have come to light.Universal reconciliation uses a multidisciplinary approach across the entire mining value chain to identify both opportunity and loss of value and to maximise operational performance. This paper will look at the operational effectiveness of universal reconciliation and will outline the important elements that make it successful, including how to map out the detail underpinning modelling, planning and execution processes. We do this by documenting the physical processes, logical work practices, organisational roles and responsibilities, data origin and quality, working assumptions and information management practices at an operation. The results quickly show how misinformation and assumption causes suboptimal decisions to be taken, where inefficiencies exist and what the opportunity is to remedy these issues.A universal reconciliation study opens up an opportunity for stakeholders to reassess how the operation should be run and how operational effectiveness should be measured. Clear envelopes for reconciliation become obvious and questions about the practicality and data quality can be addressed.A reconciliation code of practice is a key element of a successful universal reconciliation project and the authors outline the important aspects that will provide an operating model, showing the effectiveness of the resource and reserve modelling, the practicality of the mine planning and scheduling practices, how well the mine operations team are executing these schedules and how effective the processing area is given what it is fed. Most importantly, a system that allows operations time to react before the losses become systemic and that is based on identifying early warnings from hard data when these processes start to wobble is outlined. Finally as a case study, the revenue and cost benefits resulting from universal reconciliation diagnostic projects for nine mine sites is documented.CITATION:Hargreaves, R and Morley, C, 2014. Universal reconciliation – a multidisciplinary approach across the entire mining value chain to identify loss of value and maximise operational performance, in Proceedings Ninth International Mining Geology Conference 2014 , pp 411–420 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

The growth of "Unit Load-cargo handling technology in world cargo lin- er trades over the last decade has cre- ated a situation in which special pur- pose-vessels (cellular container ships, roll-on/roll-off vehicle deck ships and Lash type vessels) are rapidly replac- ing conventional cargo ships, the principal means previously available for transporting heavy lifts. Consequently heavy lift traffic has tended to accumulate awaiting ship- ment, especially where discharge is required in "off beat" locations. A partial solution to this problem will be provided by new and small but exceptionally versatile ocean going heavy lift carriers now finding their way into world trade routes. These new ships combine extremely high lifting capacity, high manoeuvreability and exceptionally shallow draft with bow and stern Ro/Ro capability. They can handle rolling loads of exceptional size and weighing up to 1,000 tons Each. But the problem is a far larger and more serious but essentially a domestic one. Major industrial pro- jects in Australia will require pro- gressively heavier and larger plant and construction sites are becoming much more inaccessible. Whereas these new ocean going heavy lift carriers have ample capacity to satisfy part of the total transport requirement, there is clear evidence to show that domestic transport resources have little if any potential for increase in capability at the same rate as demand or at the same rate as sea transport facilities. Resolution of the larger problem is within reach but only through a pro- perly co-ordinated approach to future planning for the overall needs of large scale projects on a national basis. This co-ordinated approach must involve Federal and State government transport administrators, railway and highway authorities, shipping and road haulage interests and finally the planners of the projects which require these improved heavy haulage services.

Jan 1, 1973

By M Taylor

The Project Specification and Technical Requirements documents associated with several recent large road tunnel projects within Australia have specified the application of AS/IEC 61508 – FunctionalSafety of Electrical/Electronic/Programmable Electronic Safety Related Systems at very high performance levels for the various control and fire life safety systems associated with such facilities.This paper seeks to explore the implications of referencing this standard within the road tunnel services context in terms of practicality, complexity and cost, whilst providing some examples of how a high safety integrity level (SIL) level can theoretically be achieved given current hardware availability.

Mar 8, 2011

Research on the Differential Flotation of Iso-Floatable Lead-Zinc Sulfide Ore

Sep 13, 2010

By D Johansson, C Yi

Blasting techniques are widely used to fragment rock masses into smaller pieces. Numerical modelling is an efficient method employed by many researchers in the blasting field. It is difficult for a conventional continuum-based approach such as the finite element method (FEM) to model the rock fragmentation by blasting and the expansion work on the rock by explosive and its detonation products. In this paper, the particle blast method (PBM) was employed to model the behaviour of the detonation and a bonded particle model (BPM) was used to model the brittle material to be blasted. A mortar cylinder with a centrally placed hole for the explosive was modelled and the results were compared to the experimental data. The blast process from crack initiation to fragment formation was analysed. The influence of coupling ratio on fragmentation was also investigated.CITATION:Yi, C and Johansson, D, 2015. Discrete element modelling of blast fragmentation of a mortar cylinder, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 793–798 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By C Bie, S Li, P Xiao, P Zhao, H Lin

"Based on solid simulation material research, the simulation conditions for methane and coal solid-gas coupling were obtained using solid-fluid coupling theory. Using sand as the aggregate and paraffin and oil as the cementing agents, a material suitable for solid-gas coupling simulation was developed. A permeability testing instrument was also developed, and the compressive strength, brittleness parameters and seepage velocity of material were tested with different aggregates. The results showed that as the paraffin content increased, the compressive strength of the material increased but the permeability decreased. The oil removed the drawback of intensely changing material compressive strength. By setting a different ratio of aggregate to cementing agent, it can simulate rocks with different strengths and permeability. Applying the material to a mining simulation experiment revealed a relationship between methane seepage velocity and overlying strata movement. By extracting pressure relief gas from Shanxi Tianchi coalmine drainage, the authors found that the mining fissure zone was a storage area of pressure relief gas, and a gas drainage system can be placed to achieve good results. CITATION: Li, S, Zhao, P, Lin, H, Bie, C, Pan, H and Xiao, P, 2015. Character of simulation material of coal – rock and gas solid-gas coupling and engineering application, in Proceedings The Australian Mine Ventilation Conference, pp 105–110 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 31, 2015

By S Nkwanyana, I Govender

Batch experiments in a 0.6 m diameter mill have shown that improvements of about 13 per cent in the efficiency of energy utilisation can be realised in ball mills by replacing 25 per cent of the ball charge by an equivalent volume of cost-free critical size pebbles from AG/SAG mills. For a mill of a given size, speed and charge filling, the rate of size reduction of ore particles depends on (i) the frequency of grinding media collisions (ii) the probability of capture of ore particles between the colliding grinding media (iii) the probability of fracture of the captured particles. The probability of fracture depends on the magnitude of collision energy. The distribution of collision energy into shear and impact events determines the relative strengths of attrition breakage and impact breakage. The efficiency of energy utilisation depends on which of the two mechanisms of breakage is more desirable in a particular milling stage. In this paper collision data from a series of DEM simulations of a mill charged with steel media and a mixture of steel media and pebbles is presented in energy spectra and spatial distribution maps. The data provides the necessary detail to elucidate the improvements in the efficiency of energy utilisation in ball mills when using a mixture of pebbles and steel media.

Aug 24, 2022

THE following paragraphs represent an endeavour to describe, briefly the equipment used for the manufacture of sulphuric acid and superphosphates by the Corporation.SULPHURIC ACID PLANTS.Two separate units are in operation, No. I Plant working on sulphur dioxide generated from pyritic ore, No. 2 Plant working on sulphurous gases obtained from the Huntingdon-Heberlein desulphurizing process. The latter plant is unique in being the first installation for the successful use of these gases.

Jan 1, 1918

By A R. Bye

The mining industry is facing some key challenges that provide a compelling case for geometallurgy initiatives. Over the last 30 years, the average grade of Australian orebodies being mined has halved while the waste removed to access the minerals has more than doubled. In the last eight years, the industry’s energy consumption has increased 70 per cent while multi-factored productivity has fallen 24 per cent. The paper documents a broad range of industry case studies which demonstrate strategies for gaining value from geometallurgy.The mining industry constantly faces the key questions of how significant ore variability is on mine valuation and how would knowledge of the variability change the mining schedule, mine to mill design and operation. Using case studies the paper describes the methods used for incorporating mineral extraction attributes into orebody models and their technical integration into daily operation as well as mine planning optimisation. While pit optimisation from a fully attributed geometallurgical model highlights areas of opportunity and risk it is shown that during the scheduling phase of mine planning that significant value can be added. The benefits from these projects included reducing geotechnical and environmental risk, improving mine to mill performance, option analysis and quantified cash flow risk. There is growing acceptance within the minerals industry that ‘realistically assumed modifying factors’ defined by a competent person/s are not sufficient to mitigate the risk of funding mining ventures. Geometallurgy is moving away from factored ore reserves to data-rich block models providing reliable information for mining, metallurgical and environmental considerations.

Sep 5, 2011

By C R. Fountain, R J. Sinclair

The zinc industry is dominated by the electrolytic zinc (EZ) process. The EZ process has a low tolerance for impurities, resulting in tight concentrate specifications. Many mining companies sacrifice zinc recovery in order to meet smelter specifications. Some have ore-bodies that cannot be economically developed because too much metal has to be sacrificed, or it is just not possible to meet the specification. The BUKA Zinc Process (BZP) has been developed as a method of producing high-quality zinc from a wide range of concentrates. It can have lower capital and operating costs than the conventional zinc and lead production routes. Advantages accrue from increases in metal recovery during concentrating, smelting and refining; the elimination of most of the capital and operating costs associated with lead smelting; reduced transport costs; lower zinc refining costs; reduced refinery residue disposal costs; and reduced future environmental liabilities. This paper describes results of testwork that has been undertaken to demonstrate the viability of the BZP on both test rig and laboratory-bench scale.

Jan 1, 1998

Bacteria can play a key role in the processing of 'difficult' ores. Bioleaching opens the way to potentially extract copper from vast amounts of otherwise hard to process refractory low-grade chalcopyrite. In my talk I will outline our research philosophy to develop bioleaching as a Precision Processing unit process step. In our view, Precision Processing is a sophisticated approach to mineral processing where the ultimate goal is to measure and characterise the ore body in-ground and in real time during mining, allowing the down-stream unit processes (bioleaching, in this case) to be continuously tailored and tuned via feedback and feed-forward controls to obtain the highest possible recoveries at the lowest possible cost and environmental impact. I will describe some of the work that we are undertaking to better understand the interfacial phenomena underlying the fundamental bioleaching process with the aim of coming to a Precision Processing approach. We use techniques such as interfacial electrochemistry (scanning electrochemical microscopy, SECM), AFM, zeta potential measurement, and synchrotron science to elucidate the parameters that drive bacterial selectivity and adhesion, bacterial metabolism, and dissolution and precipitation processes for model systems and real chalcopyrite ores. As examples of our research, I will discuss in some detail our method to produce and characterise micro-patterned CuxS - silica thin films as model substrates for electrochemical and bacterial adhesion work and our approach to the interfacial chemical characterisation of extracellular polymeric substances of bio-active bacterial cells. I will also cover some of our recent findings relating to measurement and interpretation of bacterial adhesion on sulfidic substrates and its implications for bacterial adhesion and substrate selectivity. After having identified and discussed crucial leaching parameters, such as pH, Eh, T, [Cu2+], and [O2], the talk will go on addressing some of the early achievements and challenges encountered in our work to design and prepare low-cost, rugged sensing devices that allow the in-situ (in this case, in-dump or in-heap) localised measurement of these parameters. I will conclude my talk by painting the picture of how the work of our group might contribute to realising the dream of transforming bioleaching into genuine high-tech Precision Processing of minerals. This is an ABSTRACT ONLY. A full-length paper was not prepared for this presentation.

Sep 13, 2010

By D A. Bowman, S Schafrik

With the goal of reducing injuries and fatalities related to haul truck accidents, this research investigates technologies and intervention strategies for improving worker training using a virtual environment (VE). Funded by the National Institute for Occupational Safety and Health (NIOSH), this research specifically focuses on training workers in preshift inspections of haul trucks to avoid preventable defects from causing worker injuries and expensive equipment damage. Improved training in these inspections is expected to increase uptime. The VE developed to train workers for preshift inspections consists of three phases: the virtual tour, the virtual inspection and the shift simulation. The virtual tour introduces information necessary to conduct a preshift inspection by guiding the worker around a haul truck, identifying parts to be inspected and explaining defects to look for. The virtual inspection assesses retention as the worker navigates around a haul truck and identifies defects. During the shift simulation, the worker is shown a simulation of the work shift, which animates severe consequences of any overlooked defects to emphasise the importance of preshift inspections. To provide multiple training platforms, desktop and CAVEÖ versions of the training VE were created. Flux Studio was used to model the environment and to produce Virtual Reality Modelling Language (VRML) files for the desktop version. DIVERSE, an application programming interface, was then used to implement a more realistic version of the VE in a CAVEÖ, a room-sized visualisation system. Initial feedback from mining colleagues indicates that the training VE may replace normal classroom training for preshift inspections in the future. As opposed to PowerPoint presentations and instructional videos, the training VE provides better spatial understanding of the location of parts and incorporates interactive features to actively engage drivers in the learning process, which may result in better retention. Initial feedback also indicates that minor improvements can be made to the virtual tour and virtual inspection phases.

Jan 1, 2008

By R Goater, P Kirsch, S Goater, I Goater

With staff productivity and retention a crucial factor in the longevity of AustraliaÆs mining industry, some mining companies are increasing their focus on the health and well-being of their people, to minimise the risks of deteriorating health in an ageing workforce. Many of AustraliaÆs mining operations rely heavily on long distance commuter (LDC) rosters, which are argued to have a significant impact upon worker health, wellbeing and lifestyle choices. The potential impact of workforce health on mine safety performance, efficiency and operating practice is an interesting additional line of enquiry. Food choice, exercise and recreation initiatives offer living and working conditions that æempower healthy choicesÆ in the shift worker community, but do not guarantee improved worker wellbeing. This paper explores first-hand the experiences of one individual over two and a half years of employment at different mine sites, under different shift conditions and across different operating crews. Novel insights and recommendations concerning the LDC lifestyle are offered through integrating reflections on one individualÆs fly-in, fly-out (FIFO) experiences in open pit mining operations from personal, family, professional and academic perspectives.CITATION:Goater, S, Goater, R, Goater, I and Kirsch, P, 2012. This life of mine - Personal reflections on the well-being of the contracted fly-in, fly-out workforce, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 31-40 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By M Wen, J Gerit, C A. Pelletier, D Muggli

On-land waste rock dumps at BHP Billiton Base MetalsÆ Island Copper Mine (ICM) near the northern end of Vancouver Island, B.C. continue to discharge ARD. These waters, which amount to approximately five million cubic metres each year, are injected into a three-layer, meromictic pit lake for treatment. The top layer is brackish water, replenished by each yearÆs rainfall (amounting to nearly 2 m/year). This top layer of water must meet effluent permit limits for heavy metals. This water eventually exfiltrates through a æbeachÆ waste rock dump, which is 93 per cent submerged along the north shore of Rupert Inlet. The middle and bottom layers of the Pit Lake are saline and currently oxic (2 mg/L dissolved oxygen) and anoxic (0.03 mg/L dissolved oxygen), respectively. Spreading of a liquid fertilizer every ten days throughout the top layer results in plankton and bacterial blooms that scavenge zinc, copper and cadmium out of this layer eventually to become mineral sediment in the bottom of the pit lake. Adsorption on planktonic skeletons and mineral precipitates also scavenges these dissolved metals from the middle and bottom layers to form bottom sediment. Sulfate reduction has recently begun in the bottom sediments. Diagenetic processes in the bottom sediments will eventually transform most of the dissolved heavy metals into insoluble sulfides. Cycling of ferric iron between the sediment and the water column and back seems to contribute dramatically to the biogeochemical metal removal processes. This biogeochemical system serves to maintain the top-layer water well within permit limits for discharge to the environment.

Jan 1, 2003