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By S Rogers, D Stead, E Eberhardt

The last decade has seen a major increase in use of the discrete fracture network (DFN) approach applied to cave mining problems, often integrated within more complex geomechanical simulations. Because the value of the DFN model directly depends on the quality and quantity of available field data, there is the need to apply dedicated mapping procedures to collect sufficient structural data at the required engineering scale. This paper attempts to address several key questions about DFN modelling; for example: are current methods for fracture mapping suitable for DFN modelling? What are the critical parameters that we need to measure and what do we need to change in the current practice? Particularly at the earlier stages of a cave project, engineers may have to account for the lack of appropriate data, which manifests itself in the form of increased uncertainty and the difficulty to characterise variability in an objective manner using a limited set of data. DFN models could in principle be generated using limited data by assuming statistical distributions for the sampled parameters; however, engineers would need to be aware of the implications that such limited knowledge (and increased uncertainty) would have on stability analysis, fragmentation analysis and mine design. When used correctly, a DFN approach offers practitioners the opportunity to:maximise the use of fracture data collected from mapping of rock exposuresgenerate more realistic synthetic rock mass modelsprovide estimates of natural fragmentation that also account for rock mass variability.CITATION:Elmo, D, Eberhardt, E, Stead, D and Rogers, S, 2016. Discrete fracture network modelling – importance of accounting for data uncertainty and variability, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 845–852 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By T B. T Nguyen, L Matthews, D O’Dea, T Honeyands, T Harvey

Productivity and fuel consumption of the blast furnace is driven by the quality of the iron ore sinter, which in turn is related to the sinter mineralogy. The sintering conditions including temperature and gas composition have a significant influence on the formation of melt and finally the mineralogy of the sinter. In this work, analogue sinter tablets were produced from iron ore fines in a laboratory furnace with tightly controlled temperature profile and oxygen partial pressure in the gas. The mineralogy of the sinters was analysed using reflected light microscopy. The results showed that increasing thermal enclosed area (area enclosed by heating and cooling curve above a reference temperature) reduces primary hematite and platy silico-ferrite of calcium and aluminium (SFCA) contents. This is attributed to increasing melt formation, leading to greater assimilation of the iron ore particles. Lower magnetite was found for tablets with greater median pore size, which is thought to be due to greater oxidation of magnetite to hematite during cooling in air. It was also found that higher alumina content was found to result in more SFCA formation under the same heating/cooling conditions, whereas tablets with higher goethite had higher assimilation and produced more secondary hematite on cooling. Finally, it is necessary to relate the enclosed area to the temperature at which the melt formation becomes significant which strongly depends on chemical composition of the ore studied.

Nov 8, 2021

There was a time, in the memory of some here tonight, when the annual meeting of The Institute was a nostalgic occasion. Often, in the 1920s, there was comment on the decline of Australian mining and on the lack of new mineral discoveries. When some of our Presidents prayed then for a new Bendigo, and instead were given a Mount Isa, they were justifiably disappointed because of the vastly different capital requirements.In 1967 the mining picture is very different. The recent mining developments in Australia are certainly as important as several Bendigos and several Kalgoorlies. The mining industry in Australia has never been more dynamic than today (Table 1). And if we ask why it is so dynamic, the answer lies in the role which overseas capital is playing in the industry. The contribution of overseas capital should concern us not only because we are members of the mining and metallurgical profession, but also because we have a duty to make our profession contribute as much as possible to the well-being of Australians. It is not sufficient to argue that overseas capital is good for the mining industry; we must also examine whether it is good for the economy and the nation. In this context the current criticism of the inflow of overseas capital into Australian mining is useful, for it gives us an opportunity to see what has resulted from the inflow.In discussing this question I do not suggest that we emulate Captain Hancock, that legendary Moonta mine manager who, according to Oswald Pryor's cartoon, used to say to his miners: "When I say a thing is, it is, even if it isn't". The question can only be discussed on a factual basis; and I would submit that many of the important facts relating to overseas capital in our mining industry are often overlooked or ignored. I would further submit, on the basis of these facts, that Australia's present day mining industry has been largely built on overseas capital and that the overall benefits of that capital to Australia have been enormous.

Jan 1, 1967

By Z Zhao

Coal dust is hazardous to underground coal workers and water spray is the most common and economic method for controlling coal dust. Previous studies proved that the addition of surfactants can improve the performance of water spray on coal dust suppression. The evaluation methods for surfactants vary from different studies. The zeta potential test is a common method for evaluating surfactants with ionicity. Generally, the suspension of coal dust with pure water usually showed a negative value of zeta potential. The addition of cationic surfactants can increase the zeta potential to a positive value with a small dosage, while the addition of anionic surfactants can only lower the zeta potential. However, there is a lack of comprehensive study to investigate the relationship between the zeta potential and the suppression performance for coal dust. The aim of this study is to reveal the consistency and discrepancy between the zeta potential and the suppression efficiency of a surfactant. Firstly, the mixture of cationic surfactant solutions and coal dust would be evaluated by the zeta potential test. The wind tunnel tests would then be conducted for the same surfactant solutions to measure and calculate the suppression efficiency. It was found that the addition of surfactant can increase the zeta potential and the suppression efficiency and it reached the greatest efficiency when the zeta potential approached to zero. The equilibrium of zeta potential can benefit the suppression performance of surfactants in the wind tunnel test. The result of this study can achieve a better understanding of the mechanism for coal dust suppression. The selection of surfactants will also be suggested for researchers or industries in terms of coal dust control. It would be more economic if a similar performance could be achieved by less consumption of surfactants.

Oct 12, 2022

Sheaves are a critical safety component in a winding system and are expected to survive such extreme loading events as rope break. Sheave designs have often been developed and evolved empirically, consequently many existing sheaves are not necessarily subjected to the detailed analyses that are possible using todayÆs design tools. The design philosophy for sheaves is that the rope should be the weakest link in the system so that associated equipment can function safely for any load up to rope break. A number of failure mechanisms must be considered, but buckling is often prominent. During the course of investigating the feasibility of upgrading the hoisting capacity of a winding system, the capacity of all critical components was reviewed. The sheaves in the system were found to have insufficient spoke buckling capacity for the specified rope. A proposal to increase the spoke buckling capacity by connecting spokes together using a simple tie arrangement was evaluated and found ineffective. An alternative tie arrangement concept was developed and evaluated and shown to be adequate. This paper describes the finite element model, analysis approach and results for the original sheave and the two modifications. The contribution of the sheave rim to the total buckling capacity is evaluated. Some practical issues for spoke tie modifications are discussed.

Jan 1, 2005

Fluid circulation occurs in oceanic crust of all ages, at the seafloor spreading axis, on mid-ocean ridge flanks, in the ocean basins, and in subduction zones. In the first three settings the fluid originates as seawater. At the axis and on the ridge flanks, the circulating seawater produces a major chemical exchange between the oceans and the crust. Based on heat budget constraints, between 10 and 40% of the river flux of Mg can be taken up during high-temperature alteration of the basaltic crust along the mid-ocean ridge axis. Most of the hydrothermal -heat loss, however, occurs on the mid-ocean ridge flanks, where the temperatures are lower and the seawater flux correspondingly larger. The estimated heat loss on the flanks is so large that upwelling must occur over a large fraction (5-30%) of the seafloor less than 65 Ma in age, at seepage velocities on the order of 10 to 100 cm/yr. The circulating seawater need lose less than 1 to 2% of its Mg content in order to solve the Mg mass balance for the oceans. Fluids in subduction zones are commonly less saline than seawater and are rich in methane and other light hydrocarbons. These fluids may originate by dewatering of the downgoing slab. If so, they may close the geochemical cycle of H2O that began with hydration of the basaltic crust at the ridge axis.

Jan 1, 1990

By R Grogan

Nautilus Minerals Inc is a sea floor resource exploration and development company focused on developing the Solwara 1 Project, a copper-gold sea floor massive sulfide deposit in the territorial waters of Papua New Guinea, for which it holds a mining lease and associated environment permit.Economies depend upon four key types of capital: built, natural, financial and human. Natural capital consists of the ‘minerals, energy, plants, animals, ecosystems (climatic processes, nutrient cycles and other natural structures and systems) found on Earth that provide a flow of natural goods and services’ (Daly and Farley, 2004). Many ecosystem goods such as fish, fruit and water are already valued and sold in markets; however, some ecosystem services are not amenable to markets and have remained unvalued in traditional accounting methods, even though they provide significant value (such as flood protection, climate stability etc; Batker and Schmidt, 2015).There are now economic methods available to quantify and value natural capital and many non-market ecosystem services. When valued in dollars, these services can be incorporated into a number of economic tools, including benefit-cost analysis, accounting, environmental impact statements, asset management plans and rate of return on investment calculations. Their inclusion ultimately strengthens decision-making. When natural capital assets and ecosystem services are not considered in economic analysis, they are effectively valued at zero. This omission can lead to poor decisions, inefficient capital investments, higher incurred costs and losses due to unexpected events (Batker and Schmidt, 2015).In 2015 Earth Economics was commissioned by Nautilus Minerals Inc to conduct an independent, objective environmental and social benchmarking analysis of the proposed deep seabed Solwara 1 mine with terrestrial copper mines (referred to as ‘the report’). The report represents the first ever natural capital accounting and ecosystem goods and services framework for seabed mining.The report compares the proposed Solwara 1 mine with three terrestrial mines: Bingham Canyon (Utah, USA), Prominent Hill (South Australia, Australia), and Intag (a proposed mine in Intag Province, Ecuador), and provides a natural capital accounting assessment for all four operations.CITATION:Grogan, R, 2016. Natural capital accounting – a sea floor mining application, in Proceedings Life-of-Mine 2016 Conference, pp 2–4 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By J Bohm, B Csoke, I Tarjan

In process technology, especially in coal preparation, it is often necessary to have a continuous knowledge of the average density of granular material in order to achieve both quality control and process control. The paper presents a new method and means supported by laboratory measurements for the rapid, practically continuous, determination of the average density of continuously supplied granular material through frequent sampling.

Jan 1, 1993

By M Hassall, E Humphries

Personal risk assessment processes, also known as Take 5 or SLAM (Stop, Look, Assess, Manage) have been utilised in high hazard industries for over 30 years. However, there is limited research to understand if a personal risk assessment process improves safety and health outcomes. The author’s learnings during discussions with training participants in G3/G-MIRM (Risk Management Systems) and G2 (Risk Assessment for Supervisors) courses have provided them with significant insight into understanding if a personal risk assessment process is valued across a number of mining industry organisations. These discussions arise when the four-layer model is presented (Figure 1) where ‘Layer 4’ represents the last resort risk checking activity. In this context, training participants agree that this process has value. However, the consistent opinion is that the personal risk assessment process is not effective, that it is a ‘tick and flick exercise’ and is not achieving the desired outcomes.

Apr 16, 2024

Financial markets are subject to constant change and project finance, as a product within these markets, adapts and will continue to adapt with those changes. A meaningful discussion of these adaptations requires an understanding of differences between non-, limited and full recourse project finance. The reasons sponsors seek and lenders provide project finance are also pertinent in this context. Arranging a project, financing package can be a canplex and time consuming task. An important first step is choosing the right advisor for the assignment and then structuring and tailoring the financing before approaching prospective lenders. The last thirty years has seen changes in the needs of sponsors and the ability of lenders to meet them. These shifts in preference may well be a guide to the future. Several major project financings successfully canpleted in Australia in the last few years and more recent examples are broadly discussed. Project finance will be keenly sought in the future and the form and nature it takes will continue to vary.

Jan 1, 1983

The considerations which led to the decision to_ install discs at the Dampier Pellet Plant of Hamer ley Iron Pty. Ltd. are described. Initial testwork showed that the ore could be ground dry in open circuit to a Blaine index of 2500 cm2/g and that it pelletized readily. The various design criteria including diameter, slope, speed, motor size, depth of sidewall, feed point and water spray location were then determined. Plant performance after commissioning is described including the various problems encountered and the modifications since carried out to overcome them. The main problem was quickly identified as disc feed rate control. Various bin and bin feeder modifications were tried to overcome the effects of the fluidising characteristics of the dry ground ore. Other factors found to affect disc operation are ore size distribution, additives and operator competence.

Jan 1, 1974

By Morrison R. S, Doennilan N

Recent mapping (1989-1992) by the Northern Territory Geological Survey in the Tennant Creek 1:250 000 map sheet area has resulted in substantial revision of the lithostratigraphy of the Tennant Creek Block (Donnellan, Hussey, and Morrison, in press). Briefly, the former Warramunga Group (Dunnet and Harding, 1967; Dodson and Gardener, 1978) is divided into the Warramunga Formation, and an overlying less deformed volcano-sedimentary succession, the Flynn Subgroup. The latter is conformably overlain by the Tomkinson Creek Subgroup of the Tomkinson Creek province in the north of the Tennant Creek Inlier. These two Subgroups constitute the Churchills Head Group which is essentially equivalent to the Hatches Creek Group of the Davenport province to the south of the Inlier.

Jan 1, 1994

By H G. Poulos

Prediction of ground deformation caused by soft ground tunnelling is an important problem facing design engineers. The ground deformations are caused by the closure of the gap formed around the tunnel due to the tunnelling procedure and soil intrusion via the tunnel face into the tunnel. There are three different approaches that are commonly used in practice to estimate the ground deformations due to tunnelling, namely, empirical methods, analytical methods and finite element methods. One of the important issues of tunnelling in urban areas is the assessment of the likely impact on adjacent pile foundations of ground movements arising from tunnel construction. The main objectives of this paper are two-fold: first, to assess the available methods to estimate the tunnelling-induced ground deformations, and second, to examine the effect of such ground deformations on adjacent piles. Analytical solutions to predict the tunnelling-induced ground deformation developed by the authors are used in this study. These estimated ground deformations are imposed on the pile in simplified boundary element analyses to compute pile responses. The influence of various factors such as tunnel geometry, ground loss ratio, pile diameter and ratio of pile length to tunnel depth are examined in this study.

Jan 1, 1999

In the last several years we have seen the demise of the Department of Mining and Metallurgy at the University of Melbourne, the removal of extraction metallurgy from the Department of Metallurgy and incorporation of it within a School of Mines at the University of New South Wales, and the joining of a small Department of Metallurgy with a Department of Chemical Engineering to form a Department of Chemical and Materials Engineering at the University of Newcastle. Most of these changes have been forced by the logical application of the principles of accounting, the currency for such accounting being the Whole Student Unit (WSU). It is not my intent to address the problem of attracting young people into courses in metallurgy (including extraction metallurgy) which, at present, is the only way to introduce black ink into the WSU accounting ledger. Rather, I wish to express my disquiet over the trends, illustrated by some of the above occurrences, of separating out extractive metallurgy from METALLURGY by suggesting in broad terms how a course in metallurgy should be structured. I firmly believe that the mechanical metallurgist and materials engineer need an exposure to chemical and extractive metallurgy; similarly, the extractive and process metallurgist should, in my view, have a good grounding in the interrelationships between composition, structure, and properties, this topic being the core of the basic subject physical metallurgy.

Jan 1, 1987

By V A. Chanturia, T N. Matveeva, V V. Getman, A Yu Karkeshkina

The development and application of new effective environmentally friendly reagents for the flotation of thin and ultrathin mineral components is an urgent task. The analysis of the nomenclature of chemicals, including flotation reagents and flocculants, showed that water-soluble polymers (WSP) might be used in flotation separation of fine grinding products containing non-ferrous and precious metals. Water-soluble polymers that are responsive to temperature changes are the most attractive as reagents during flotation. These are the thermo-responsive polymers or thermomorphic polymers. The presence of nitrogen and oxygen atoms in the polymer molecule contributes to the formation of a coordination bond with non-ferrous and precious metals. A research conducted at the ICEMR RAS within the framework of the scientific school of Academician of the Russian Academy of Sciences Chanturia helped to develop a method of flotation of finely ground mineral particles containing valuable components using modified thermomorphic polymers. The paper focuses on the experimental study of poly (vinyl caprolactam) (PVC) as a flotation reagent for gold recovery from finely ground mineral products. PVC is a ready-made water-soluble thermosensitive polymer that does not require complex synthesis. PVC has a high ability to form complexes in an aqueous environment when heated. According to experimental data, the polymer interacts with gold nanoparticles, contributing to the extraction of gold from fine mineral products and the tailings that makes it perspective as an additional flotation agent for the processing of gold-containing ores.

Aug 24, 2022

By Y Peng, D Liu, S Vink, B Wang

There have been strong industrial observations that clay minerals have a deleterious effect on mineral flotation grade and recovery. However, rigorous explanation on the role of clay minerals in flotation and effective ways to reduce their negative effects are not available. In this study, the flotation behaviour of low quality and high quality coal samples were examined at the Xstrata Oaky Creek Coal plant, and laboratory in fresh and recycled water with high ionic strength. Anionic and non-ionic dispersants including lignosulfonates and triblock copolymers were also tested with an objective of improving coal flotation in recycled water. It was found that overly stable froth was produced in the flotation of both low quality and high quality coal samples in saline water. Speciation modelling indicated precipitation of hydrophilic components which may adversely affect the flotation. Despite the overly stable froth, saline water produced much higher combustible recovery than fresh water without significantly losing the product quality. Lignosulfonate dispersants displayed a potential to improve the flotation in fresh water, but not in saline water. Significant flotation improvement was achieved with the triblock copolymer examined in both fresh and saline water.CITATION:Liu, D, Wang, B, Peng, Y and Vink, S, 2012. Determining the effect of clay minerals on coal flotation using saline water, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 151-158 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By A Marta

Geomembrane (GMB) liners are being used more frequently for the storage or capping of mine waste due to stricter regulatory requirements relating to environmental protection. The longevity of any liner system will be a function of environmental conditions, design (including materials selection), construction and condition monitoring during operations or closure. Based on experience and case studies, this paper presents a review, from design to handover, of some of the smaller and often overlooked details that can have significant impacts on the performance of the GMB and the project overall.The topics covered will include approaches to selecting and testing GMBs to ensure they are suitable. Design considerations to aid installation and quality assurance during construction. Understanding action leakage rates and the consequences of leakage when it creates whales. Construction quality control and assurance procedures, including a brief discussion on non-destructive liner integrity testing. CITATION:Marta, A, 2018. Geomembranes – from design to handover and some of the lessons learnt, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 190–207 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By A J. Cornah

"The mine geologist’s role in classifying ore from waste during grade control represents a critical link in the mining value chain. Any improvement in the ore/waste selection success rate (thus reduction in misclassification) which can be delivered by the mine geologist represents a value proposition. Improvement achieved without additional operating cost (for example extra drilling and sampling) will directly and immediately add value to the mining operation and therefore clearly must be pursued. Such improvement may be leveraged from existing resource drilling data which are typically less numerous but better quality than the grade control data. They are usually excluded from grade control estimates (termed the ‘base case’ approach here) because of the differences in quality.Various specialised geostatistical tools are available to account for differences in precision and accuracy between data sources during spatial estimation. This paper uses a conditional simulation (CS) case study to assess the benefit of integrating resource data into grade control estimates through ordinary kriging (OK) of pooled data sets, cokriging (CK), and ordinary kriging with variance of measurement error (OKVME) when the grade control data are:unbiased but increasingly imprecisebiased and increasingly imprecise. The premise assumed is that the resource data are unbiased and precise.The paper demonstrates that, if appropriately handled, resource data may be used to improve grade control estimates and thus improve ore/waste selection success without additional operating cost. Where grade control data are imprecise but unbiased it is recommended to integrate resource data using OKVME. This re-appropriates kriging weights from less precise to more precise data locations and improves the grade control estimation precision compared to the base case; it consequently provides an improvement in the grade control selection success rate. If grade control data are associated with significant bias, integration through CK is recommended as the biased data are zero sum weighted. CK consequently provides an unbiased estimate with some improvement in estimation precision compared to the base case and consequently improvement in the ore/waste selection success rate.CITATION:Cornah, A J, 2014. Incremental improvement of grade control models using resource data, in Proceedings Ninth International Mining Geology Conference 2014 , pp 387–396 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 18, 2014

By A D. Campbell, G R. Power

The increasing availability of marker data in sublevel caving operations is changing the way draw can be managed to achieve positive recovery outcomes in these mines. This paper describes how marker data has been incorporated into flow simulations to help calibrate full mine ore recovery simulations for the forecasting and optimisation of recovery.Some flow modelling techniques do not use marker data, relying instead on the outcomes of physical and numerical experiments to guide assumptions about an idealised recovery flow shape. Other mines have access to marker trial data, but find it difficult to specifically link this marker trial information to their recovery models. This can make it difficult to create a link between the marker trial information and recovery forecasting and limits the potential value of the marker trials at the mine.In the simulations shown here, the marker rings are fully incorporated into the flow model, and can be tracked in the model. The model is compared against the real underground marker recovery information to give the user an indication of how accurately the flow settings in the model are reflecting the conditions in the experimental marker rings. An example of use of this system at an operational mine is included.CITATION:Power, G R and Campbell, A D, 2016. Modelling of real-time marker data to improve operational recovery in sublevel caving mines, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 105–110 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By J A. M Luz, A T. Bernardes

HukkiÆs law is an empirical law, which does not take into account several events of energy loss during the fragmentation processes. Since experimental results are very difficult to obtain, for a large range of fragment sizes, the verification of the law is very difficult. The relation between fractures and fragmentation processes with fractal geometry was proposed some decades ago. Empirical laws known in this context show basic features of fractal geometry, mainly self-affinity and power law behaviour. Thus, in this work a model was developed to simulate the fragmentation process and to check the relation between energy consumption and fragment sizes. The model is represented on a regular lattice. Links can represent pathways for fracture processes. The events of fragmentation have energy given by a probability distribution function. In the model there is no mass loss. Propagation of fractures occurs as self-avoiding random walks on the regular lattice.

Sep 26, 2011