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By J Carrillo, A King

Gravity recoverable gold (GRG) is largely distinguished from other gold by its non-mineralised, metallic form, its high degree of liberation from the ore and its appreciable particle size. The gold mining industry has so widely accepted the use of batch centrifugal concentrators (BCC) and intensive cyanidation (IC) systems for the recovery of GRG that these may well be considered requirements of any plant processing ore containing appreciable GRG. The recovery of gold by gravity is quick, easy and cheap by comparison to alternatives. However, there are cases where attributes of the ore make recovery of gold by gravity and IC unusually challenging. This paper describes three examples where such challenges have been encountered and met, including those where the ore contains cyanide soluble base metals and where fine GRG is to be recovered from flotation concentrate.CITATION:King, A and Carrillo, J, 2018. Addressing challenging applications of intensive cyanidation in gravity gold recovery, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 283–290 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By S Reid, W Chen, T J. Donohue, A Katterfeld

The use of discrete element modelling (DEM) is widespread in the materials handling field, and is used for many applications. One of the important limitations in using DEM is the number of particles that can be modelled, with this limitation often resulting in increasing the minimum particle size in the simulation. This restriction on minimum particle size is usually accommodated in the calibration process where the parameters in the simulation are chosen in such a way as to reflect the presence of smaller sized particles, and in typical applications such as transfer chutes this is standard practice. However, in the application of vibrating screens the inclusion of the ‘fines’ is critically important due to their influence on the screening efficiency. In reality, the presence of fines reduces the screening efficiency for a number of reasons; however, the main mechanism that will be addressed in this study is the effect of adhering fines. This is where the fines adhere to the larger particles and are carried over into the lump stream. The approach for this study will be to firstly consider the relatively simple mechanical sieving process used in the determination of particle size distribution, and then this will be expanded to consider the application of vibrating screens.CITATION:Donohue, T J, Chen, W, Katterfeld, A and Reid, S, 2017. Addressing the challenges associated with the modelling of iron ore in vibrating screens, in Proceedings Iron Ore 2017, pp 155–160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Many operating hard-rock sulfide mines are predicted to require perpetual post-closure management to prevent environmental degradation. Causes include evaporative concentration of metals and other solutes in pit lakes, and acid rock drainage from sulfide waste-rock, tailings, and pit benches. Dilemmas posed by the prospect of perpetual management include: uncertainty in predictive models typically prevents reliable bounding on forecasts for the timing or magnitude of environmental impacts; comprehensive closure designs that can meet environmental standards may not be economically possible, particularly when applied retroactively to mines permitted under less stringent closure requirements; the publication of site-specific environmental analyses in peer-reviewed journals are discouraged in the current regulatory environment, hindering scientific advancement; and the durability of financial and government institutions cannot be assured for the long-time horizons over which mine impacts are predicted to occur. Re-evaluating mine closure in a framework of sustainable development (as proposed by the Mining Mineral Sustainable Development forum), can resolve, in part, these dilemmas. Key sustainability goals include: assurance of the social and economic well-being of the local community; assurance of the long-term environmental integrity of the region; and establishment of institutions capable of addressing (and learning from) long-term environmental management. Under a sustainability framework, impractical plans for immediate attainment of perpetually-stable closure may be replaced with a fund for long-term management of environmental impacts (eg through contaminant migration controls and exposure barriers), and a set-aside long-term growth reserve intended to eventually fund more complete closure. Fund expenditures would follow Adaptive Managementùa template for environmental-management institutions in which knowledge accumulated and uncertainty acknowledged explicitly. Under adaptive management, trusts would be flexible entities, supporting an evolving program of monitoring, predictive model refinement, and treatment. Periodic value of information analyses would target data collection efforts, refining the balance between predictable cost and uncertainty. This framework could overcome present-day financial shortcomings, enhance the field of environmental science, and meet the needs of future generations through the propagation of capita.

Jan 1, 2003

By W van der Westhuizen

Mining professionals recognise the need and application for reconciliation and value tracking. It is necessary however to examine our current reality, and evaluate the following. Do our reconciliations really balance correctly, and are we able to track value effectively throughout processes? If we are honest, in most operations the answer is a resounding no. This means that we are surrounded by fluctuation and deviations that we do not account for and do not understand. This is astounding, because given our level of scientific knowledge and the technological tools at our disposal we should have a good understanding of our environments and be able to manage them effectively. How do we manage effectively if we are surrounded by so much uncertainty? The purpose of this paper is to describe, at high level, the principles of reconciliation and value tracking, to highlight some areas where deviations are introduced into the mining process, and to propose a different approach to the apparent reconciliation and value tracking conundrum. The paper also poses several questions that need to be critically addressed at most operations. Instead of making the same mistakes each month in reconciliations, mining professionals need to acknowledge two facts. Firstly there will be uncertainty that we need to accept, since all our estimates are based on sampling, an orebody is not homogeneous and peopleÆs behaviour will influence the process, etc. Variability will always exist and lead to uncertainty. What is the current approach in the reconciliation process when a deviation occurs and how do we use reconciliation and value tracking to manage and improve our business? The second fact is that we need to stop using reconciliation and value tracking to only measure and report. We need to adopt a new approach to manage mining throughput, where reconciliation and value tracking are enablers to the success of the business. In most mining operations, significant effort goes into planning and measurement for the purposes of reconciliation and value tracking. The importance of accurate and effective reconciliation and value tracking should be to ensure the maximum utilisation of the resource, maximising throughput and enabling the business to deliver a product to its client, of the correct quality and in a timely manner.

Jan 1, 2002

By A Garvie, D Kentwell, J Chapman

"Most new mining projects require an initial assessment of the locations and volumes of potential acid forming (PAF) waste that is likely to be moved and dumped in surface waste stockpiles. This requires sampling of the waste rock zones and submitting the samples for a series of tests. Key to the outcome of the waste characterisation process is obtaining sufficient samples that are representative of the various rock types both in number and spatial distribution.Various regulatory bodies throughout Australia and the rest of the world are currently struggling with how to define minimum amounts of sampling to achieve realistic estimates without imposing excessive costs and time constraints on a project.This paper addresses two aspects of the process: what constitutes a æsufficientÆ number of samples how to use those samples in determining volumes of likely PAF material.Geostatistical methods of characterising orebodies with large numbers of samples are routinely used in the mining industry by geologists and geostatisticians to estimate and classify Mineral Resources. In theory exactly the same methods can be used to estimate PAF waste locations and volumes.In practice the number and spatial distribution of dedicated PAF waste samples at feasibility stage is typically so small that it is almost impossible to estimate the spatial distribution of PAF material with any degree of confidence at all. Consequently, the common approach is to characterise a few samples from a lithological unit and then assume that they represent the unit as a whole. This approach, however, can be fraught with risk.This paper describes some of the findings of SRKÆs evaluation of several coal projects with respect to PAF waste evaluation and highlights some common misconceptions held by people working in this area that do not have a knowledge of statistics or geostatistics.CITATION:Kentwell, D, Garvie, A and Chapman, J, 2012. Adequacy of sampling and volume estimation for premining potential acid forming waste evaluation using statistical and geostatistical methods, in Proceedings Life-of-Mine 2012, pp 79-88 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 10, 2012

Adhesion of Escherichia coli onto Oxide Minerals - Extended DLVO Theory and Flotation Behaviour

Sep 13, 2010

By M Nehring, E Topal

Nowadays mining projects are seeking new versions of evaluation that are based on the flexibility in the project. Real option valuation (ROV) is one of the modern evaluation methods that provides a tool to adapt and revise mining projects under uncertainty and future variable movements. Most evaluation approaches simply assume that some variables are fixed, such as production rate, variable cost, fixed cost and lifetime of project. The first section of this paper reviews a comprehensive study of ROV in mining projects. The paper then introduces a new model that solves problems where previous methods lacked. The new method endeavours to find maximum mining project value by adding total cost as a function of production rate into ROV. The second section has been applied to a new model on the Century zinc mine in north-west Queensland, thus illustrating the future overview of that mine. The new version of ROV gave a significant positive value for the Century Mine, when the closure and reopening options where available throughout the life of the mine. Consequently, the new method evaluates real options to add value to mining projects, maximising projectÆs value, estimating cost function, optimising production rates and offers opportunities in projects to amplify gains or to mitigate losses.

Jan 1, 2009

By N Johansson, D Johansson, A Beyglou, H Schunnesson

As demand for optimisation of mining processes increases, more attention is drawn to blast performance and fragmentation improvement. Fractures and discontinuities are among the most influential factors in blast results, therefore one of the initial steps towards blast optimisation is to gather information about the rock mass and integrate it in blast design. This paper presents a method for assessment of rock mass discontinuities and integrating it in production blasts in the Aitik open pit copper mine in Sweden.3D photogrammetric techniques were utilised to map discontinuities and distinguish domains of similar geologic structures in the pit. As a pilot study for a future campaign, four different initiation directions were tested through six pilot blasts in one of the domains. The results were compared in terms of swell and loading efficiency of rope shovels to identify the correlation between blast performance and initiation direction compared to major discontinuity families.It was established that in the trial domain, blasts initiated towards north or north-west yielded larger swell and better performance of loading. Comparing these blasts with discontinuity families show that there is a correlation between blast performance and initiation direction according to the dip and strike of these discontinuities. Such knowledge can be used for future blasts in the same domain to increase long-term operational efficiency through slight modifications in drill pattern and initiation design.CITATION:Beyglou, A, Schunnesson, H, Johansson, D and Johansson, N, 2015. Adjusting initiation direction to domains of rock mass discontinuities in Aitik open pit mine, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 385–392 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By Gluch KD

The current Mining Act has been the mechanism for administering and encouraging the State's mining industry through the 1970's up to the present. Although it has been subjected to considerable amendment there continues to be judicial challenge as well as criticism in relation to ambiguity of interpretation. Expansion of the mining industry and pressures placed upon "it by the ever increasing interaction with other land users have highlighted deficiencies in the current legislation and the need for a strong and progressive Act covering the rights and obligations of miners and their relationships with those outside the industry. - It is considered that the most positive results can be achieved by a complete redrafting of Queensland's mining administrative legislation.

Jan 1, 1987

By B Roache, J O’Brien, M Gray

Admixture use in cement products is commonplace in the construction and mining industries. Many Australian mines have an operational concrete batch plant and stock hydration control and water reducing admixtures. The benefits of admixture use, especially in shotcrete is understood and well documented. Cemented rock fill (CRF) is used to fill stope voids and create stable vertical and undercut surfaces at some Australian mines. These mines generally mix rock fill with a slurry of cement and water without the use of admixtures. Recently published work on optimisation of CRF mixes has mainly focused on the strength increases associated with changes to the mix grading proportions by the addition of fines, but not focusing on the potential benefits of admixture use. Admixture use in CRF may be the simplest CRF optimisation method, as the admixtures will often be added by the push of a button at the batch plant. A CRF testing program was undertaken to test the benefits of admixture use in terms of strength gain, using hydration control additives (HCA) and high range water reducer (HRWR) admixtures. Rock fill gradings were strictly controlled in the test process to allow clear definition of the difference admixtures provide in compression at 28 days. The testing results define admixture associated strength gains in a 6 per cent general purpose (GP) cement by dry weight CRF mix (131 kg of cement/m3). Costings have been developed to allow a mine operator to understand the cost benefits of admixture use in CRF due to reduced operating costs. Operational efficiency advances and a suggested admixture implementation plan for CRF optimisation is offered.

Nov 29, 2022

While, in the past, a great deal of attention has been focussed on technical issues and the performance of explosives in rock, the explosive user, an essential link in the chain, has often been neglected. In the mining industry, too often, the benefits of excellent technical work have been degraded over time due to the lack of definitive and documented control. Using the principles of quality management a quality training system was developed and implemented for management of explosives use at Gunpowder Copper Ltd (GCL). This paper describes the structure of the system, its development and implementation, and contains practical advice and information for managers responsible for blasting and charge crews. The paper is in four parts: I Quality systems. A brief overview of the relevant aspects of total quality management that apply to explosives use. The requirements for documentation, management and auditing are explored. 2. Training for competency. The five essential elements of Competency Board Training (CBT) are examined, including auditing. 3. The Gunpowder Copper system. Implementation of the complete training system. Documentation and its control, auditing, instructions for operators, management responsibility and means of obtaining operator ownership are amongst the issues raised. Reporting requirements are the means to effectively manage change are described. 4. Summary. The paper concludes with the tangible benefits seen by Gunpowder Copper through the adoption of a quality training System.

Jan 1, 1995

The number of employees required to operate a continuous operation was determined. The fixed and variable costs of the operation were separated, generally along the lines of labour and stores components. Proprietary `MicroPlanner' scheduling software was used to assess resource utilisation under the constraints generated by seven-day operation to determine the level of resources required and ensure that the maximum use was being made of all resources. The mine economic model was used to account for both the fixed and variable costs of the various task to determine the cost and net revenue of the various scenarios. The analysis indicated that mine output could be increased while reducing the unit production cost. Several eight- and 12-hour, seven-day rosters were sourced and ranked for their potential to improve production and communication, and for their effect on employee health and lifestyle.

Jan 1, 1995

By R Vleggaar

In addressing a short-term operational need for the relocation of a tailings storage facility reclaim pond, a mine has achieved a host of water management objectives. Through effective planning and adoption of a strategic æwhole of mine lifeÆ approach, the mine has achieved significant environmental, social and economic benefits. A review of all water management aspects across the site identified a host of other interrelated water issues and concerns which, if dealt with individually, would prove too costly for individual operational departments. When considered as a whole, however, the issues became opportunities and provided the stimulus for integration of the site water management system. The development of site water and solute balance models provided the tool by which a number of water management options/strategies could be evaluated. The conceptual design and costing of the proposed water infrastructure further facilitated the evaluation of the multiple benefits to be gained from each option. A business case could then be made to mine management for the preferred option. The recommended water management strategy finally recommended to the mine not only provided a tailings storage facility (TSF) reclaim pond, but also provided for:increased wastewater recovery from the TSF, the capture of all waste rock dump run-off, additional water harvesting from local creeks, increased wastewater reuse, improved environmental water management, infrastructure that could be used by the local community after mine closure, and overall cost savings. This paper illustrates how effective water management planning can provide both short-term economic and environmental benefits, as well as long-term social benefits.

Jan 1, 2006

Results of investigations on adsorption and desorption of CO M CH and a mixture of the two gases are described.4 Results showed that even when the equilibrium conditions contains 50% Co and 50% CH4, the gas emission in the initia' stages will contain as much as 80% CH . 4 The temperature has a small effect and so also particle size for 1.4-11.2mm. The ratio of CO2/CH gases adsorbed in coal samples depends upon t4he equilibrium pressure and this ratio decreases with pressure. Results of field tests support laboratory studies.

Jan 1, 1988

The paper describes some of the economic and human factors associated with haulroads on Mount Whaleback, a large open pit iron ore mine. These factors have combined to encourage formation of a specialised road maintenance crew which caters for haulroad construction and maintenance. Techniques used for design, construction, operation and management of haulroads are then described. Future developments are expected to effectively lower construction costs leading to an even wider application of the techniques described and consequent improvement in temp- orary roads and overall truck performance. INTRODUCTION Mount Whaleback is a large truck/shovel open pit iron ore mine located in the Pilbara region of north Western Australia. Annual production capacity exceeds 100 million tonnes per annum of waste and ore. The truck haulage fleet comprises WABCO 120 52 WABCO 3200 22 74 of which approximately 45 are operating at one time.

Jan 1, 1982

The paper describes the studies conducted to date on the short term adsorption/desorption of gases in coal from the point of view of developing techniques to predict imminent outbursting conditions in coal mines. A number of different parameters such as'dP express, K' and AV 0/60 etc. which have been effectively used overseas were studied on samples of coal from Westcliff and Leichhardt Colliery. Results indicate that these do not seem to be valid indices for predicting an outbursting condition. Based upon desorption isotherms, a new index defined as "L" has been developed which shows promising results. This index is in a position to differentiate the changes in the structures of coal and its proness to outbursts. The "LZ value determinations and its usefulness opens a new field where it would be possible to determine outbursting conditions from existing drill cores obtained during exploration studies or from long holes drilled in advance from underground workings. The index is more or less independent of the time elapsed between the extraction of a sample and the conduct of the test. The test for "L" can be conducted'on site or in the laboratory. The test is simple, easy to carry out and the "L" value for a sample can be calculated in less than 20 minutes. It could be adapted as a routine test for monitoring outburst conditions in mines.

Jan 1, 1980

Adsorption Behaviours of Humic Substances onto Iron Ore Particle Surface Humic substances extracted from lignite mainly consist of fulvic acids (FA) and humic acids (HA), which have been successfully used as good composite binders for iron ore pellets in laboratory tests and industrial production. However, there exists a general lack of understanding of the interaction between humic substances and iron ore particles surfaces. In this research, by means of zeta potential measurements, Fourier Transform Infrared (FTIR) spectrum, colorimetric method and Environmental Scanning Electron Micrograph (ESEM) imaging, the adsorption behaviours of FA and HA onto the surfaces of iron ore particles are investigated. The zeta potential results indicate that adsorption of FA on the iron ore particles can be characterised by specific and electrostatic interactions, while adsorption of HA is by electrostatic and chemical adsorption interactions. FTIR spectrum results show that adsorption force of FA on the iron ore particle surfaces is stronger than that of HA. From results of colorimetric method, compared with HA, adsorption amount and adsorption rate of FA is more and faster, respectively. FA molecule presents on the surface of magnetite in the shape of an araneose network structure according to the ESEM images, while HA molecule appears on the surface of magnetite in the form of small flocs or microclusters. Humic substances are effective to iron ore pelletisation. Comparsion of agglomeration results show that the different mechanisms of adsorption result in varied agglomeration behaviours. Theses findings above would be beneficial to the implications of composite binder for agglomeration.  

Sep 13, 2010

Adsorption Effect on Multi-Heavy Metal Ions in Wastewater by Water-Washing Waste Saccharomyces cerevisiae

Sep 13, 2010

Adsorption Isotherm Measurement of Sodium Oleate on Haematite Using Differential Thermal Analysis

Sep 13, 2010

By Sandenbergh RF

The debate on the mechanism of adsorption of gold and silver di-cyanide onto activated carbon could be divided into two schools of thought. On the one hand, it has been proposed that the combined effects of electrostatic and chemical interaction between the activated carbon surface and adsorbing gold di-cyanide anion results in the adsorption of the latter. On the other hand the `ion-pair' adsorption reaction mechanism has been vigorously advocated as the dominant mechanism responsible for the adsorption of gold di-cyanide onto activated carbon. It is maintained that gold is adsorbed onto the carbon surface as the neutral ion-pair [M"+][Au(CN)z ]". Adsorption is viewed as the result of mainly the chemical interaction while electrostatic interactions are neglected. The validity of the `ion-pair' adsorption mechanism may be challenged on a number of counts. However, the alternative mechanism (based on aqueous surface chemistry principles) has not gained general acceptance yet, because it has not been applied widely enough to explain the different adsorption phenomena associated with gold di-cyanide on activated carbon. In the present study the case in favour of an adsorption mechanism based on general aqueous surface chemistry principles is presented. A model framework is developed for the adsorption reaction mechanism of gold di-cyanide onto activated carbon which incorporates the effects of chemical and electrostatic interactions between the dissolved species, the aqueous solution and the carbon surface. This model is then employed to explain a wide variety of reported adsorption phenomena for gold di-cyanide on activated carbon, such as the effects of pH, the adsorption of different metal cyano complexes, ionic strength, and type and concentration of cations in solution. In addition the effects of cyanide and dissolved oxygen concentration were investigated. No ready explanation, in terms of aqueous surface chemistry principles, is yet available for the switch in adsorption behaviour that agrees with ion exchange to ion-pair adsorption with increasing ionic strength.

Jan 1, 1997