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Basicity(aO2−) has been known to affect the physicochemical properties of molten slags in the metallurgical processes. However, because of the impossibility of direct measurement of single-ion activity, various indirect measures such as capacity, redox equilibrium of transition metal ions, activity of basic oxides, and (theoretical) optical basicity have been proposed; but these basicity measures have been restricted within slag systems and the interaction between measuring elements and slag components has affected the quantitative estimation of slag basicity. Recently, since it was reported that solubility of noble metals in molten slags could be an indirect measure of basicity, the influence of slag basicity on the solubility of platinum and silver has been reported. The reaction mechanism of platinum dissolution into basic slags has been reported, whilst that in acidic slags has not (Nakamura and Sano, 1997; Sano and Nakamura, 1997; Nakamura et al, 1998). Richardson reported that the solubility of metals such as cupper, gold, silver, and lead in the CaO-SiO2-Al2O3 slag was presumably dependent on the atomic radius and the accommodation ability of the silicate network (Richardson, 1974). Swinbourne and You measured silver solubility in the Na2O-SiO2 slag over a wide range of oxygen partial pressure and suggested that silver would be present as both Ago and Ag0.5 in the slags (Swinbourne and You, 1999). For brevity, these previous works discussed the dissolution mechanism of silver into the slags based on the existence of silver as a neutral or molecular species. However, because the almost chemical reactions occurring in the slag are affected by the basicity, the reaction formula with O2- ion is required based on the ionic characteristics of the slag such as desulphurisation and dephosphorisation reactions as given in Equations 1 and 2, respectively.

Jan 1, 2000

By R Durchholz, A-J Heiertz, R Schmitz

Mining of lignite is the largest bulk materials handling activity in Europe. In order to mine this lignite, with an average calorific value of only a third of bituminous coal in an economical way, highly efficient opencast mining technology is mandatory. The total continuous mining of overburden and lignite was introduced more than 60 years ago and was subsequently developed stepwise into the largest mass transport system of the world. In 2011, the Inden Mine, one of three RWE Power mines, stripped 90 Mbcm of overburden to produce 22 Mt of lignite. In total, nearly 100 Mt of Lignite was produced from the three mines of RWE Power in Germany. Beside bucket wheel excavators (BWE), several high-performance in-pit crushing and conveying (IPCC) systems, which allow the adoption of continuous mining systems, even for typical shovel and truck (S&T) operations, are available today. RWE Power assists operators considering a change from the S&T to IPCC technology, both in the planning process involving large-scale belt conveyor systems and later with operational know how transfer. In a number of cases, the challenges associated with this system change have been addressed and solved successfully. One key challenge is managing the development of skills for operating the belt conveyor systems efficiently. This paper compares the effectiveness of S&T to different configurations of continuous mining operation for an up to 170 m deep mine with a total annual output of 117 Mbcm. From the mine operatorÆs point-of-view, the quantity and skill level of staffing required for operation and maintenance are discussed in detail. The main conclusion of this paper is the larger the operation becomes and the longer the mine life is, the earlier fully continuous mining systems should be planned and implemented.CITATION:Schmitz, R, Durchholz, R and Heiertz, A-J, 2012. Change challenges for large open pit mines, in Proceedings Eighth Open Pit OperatorsÆ Conference , pp 103-110 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 18, 2012

By J Tibbett, A Colebourn, B Hebblewhite, F Suorineni

The concept of Big Data refers to data sets that are so large, variable and/or complex that traditional data processing applications struggle to integrate the data for effective investigation, analysis and value generation. With advances in sensor technology and smarter equipment, the mining industry is experiencing Big Data, and in a different way to how the intelligence and marketing communities experience Big Data. Future mining will bring larger, more complicated and diverse data sets increasing the strain on traditional data integration and investigation techniques. Block caving is an important mining method for the extraction of massive, low-grade ore deposits due to its low operating cost and high production potential, given the right orebody geometry and ground conditions. This paper focuses on block caving due to its increasing popularity and importance in the future economic extraction of multiple commodities. The block cave mining system (BCMS) is a complex interrelation of factors, and due to the reliance on natural processes within the system, it is one of the least understood mining methods. Obtaining information on the factors within the BCMS generates large, complex data sets on various time scales. Each sensor network within the BCMS combines spatial and temporal information with tens to hundreds of recorded parameters. Data sets are quickly moving from multidimensional to n-dimensional. Optimisation of the BCMS is only possible through a holistic analysis approach, thus involving the integration of multiple, diverse, n-dimensional data sets (Big Data). This paper presents a current example BCMS Big Data situation involving 12 sources of information with differences in volume, data format and frequency of data generation. This suitability of virtual reality scientific visualisation (VRSV) as a solution to BCMS Big Data interpretation difficulties is then discussed. These 12 data sets can be effectively integrated using VRSV for intuitive and accelerated investigation of the BCMS. Potential future Big Data within the BCMS is presented involving 20 sources of information resulting from our increased need for monitoring and advancements in technology. Current methods of defining queries may not be suitable within these future complex, multidimensional data sets, and the potential of artificial intelligence algorithms within this system is discussed. These advancements in technology and machine learning lead to the requirement of live data acquisition and analysis. VRSV is identified as a suitable technology to satisfy the needs of real-time insight into the performance of these future caves for optimised management and reduced risk.CITATION:Tibbett, J, Suorineni, F, Hebblewhite, B and Colebourn, A, 2015. Virtual reality scientific visualisation – a solution for big data analysis of the block cave mining system, in Proceedings Third International Future Mining Conference, pp 109–116 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By C Simpson

In 2011 the forecasted world demand for iron ore continues to grow, and during this time Australia is looked upon as a reliable supplier of high quality ore. The expansion of the current Australian mines is unlikely to meet the forecast demand. New mines are therefore being actively explored for and when discovered, are quickly being developed into mines in order to meet the world’s hunger for steel.The Solomon Project area is a large new iron ore discovery, located in the central Hamersley Ranges of the Pilbara province in Western Australia. The first Fortescue exploration drill holes commenced on the project in 2007 and to date three billion tonnes (Bt) of iron ore have been defi ned within the project area. Fortescue is fast-tracking the development of the ‘Solomon Stage 1’ project, with rail and mine construction commencing during 2011, and ore to be railed to Fortescue’s existing shipping operations at Port Hedland commencing in 2012. At a designed production rate of 60 Mt/a, the Solomon operation will be one of the biggest production centres of iron ore in the Pilbara.Deposit types include the three dominant mineralisation styles of the Pilbara province, being bedded iron deposits (BID), Channel iron deposits (CID) and detrital iron deposits (DID). All these mineralisation styles are present in large concentrations within the Solomon project area, and when mined will produce two product streams. These are a single product of CID, and a combined product from a blend of BID and DID material.This paper defines the geological characteristics of the Solomon iron deposits as recognised through the exploration and development of this vast resource over the three years since exploration commenced on the project.

Jul 11, 2011

By M Allen

Energetics has been in the business of climate change for more than twenty years. This experience has only served to cement the understanding that decisions taken during design define the environmental and economic performance of any project. The 80-20 rule definitely applies, with 80% of a project’s performance being set through the first 20% of design decisions. This in depth knowledge is used for determining energy price forecasts, future carbon markets and carbon costs, current and future energy technologies, as well as giving a thorough understanding of the processes and technologies in place in the mining industry to work out what the most carbon and energy sensitive decisions during design are. Project selection and design is a gated process where decisions are taken in line with the information available at that point in the evolution of the project. Design decisions are, by their nature, dominated by uncertainty. In order to ensure that robust decisions are taken, it is necessary to ensure that the correct information is brought to bear at the correct decision point. This then defines and supplies the necessary carbon and energy information for design decisions to be correctly made. One of the most significant risks facing design engineers and decision makers in the mining industry is the future cost of energy. Part of this risk is associated with a future cost of carbon, however, a significant part of this risk is the cost, and variability in this cost, of the energy itself. This paper investigates the information required to support good decision taking during the design process.Project Managers and MetPlant Operators accept poor quality evaluations because they are generally unaware of what they should expect.The 2010 draft AusIMM ‘Guidelines for Techno-Economic Evaluations’ were collated by a subcommittee of practitioners and are regarded as best practice.They apply directly to projects and metallurgical plant evaluations, including those with a heavy technical basis. They can be applied to technical problem solving where there are no monetary computations.Project Managers and MetPlant Operators should demand that economic models and evaluations follow the six principles. They should become working tools which are easy to understand, fit for purpose, consistent, rigorous, record sources of input data, have key graphs and are rapid to audit.

Aug 8, 2011

By M Kent, D Elder, J Woodward, R Edwards, B Catto

At Tropicana gold mine (TGM), mine planning is completed from ‘one source of truth’ known as the Integrated Planning Model (IPM). The IPM is a block model which forms a core component of the TGM Mine Planning System – used for short, medium and long-term mine planning cycles, and for Mine to Mill reconciliation.The IPM was developed from a desire to consolidate long-term information contained in mineral resource and ore reserve models, with short-term information from the grade control processes, including grade control models and ore polygons.The IPM is informed initially by resource models, upon which the longer term budget and schedules are based. The IPM is routinely updated with grade control models and ore design information, providing increased confidence for short to medium term mine planning. In this format, the IPM also provides a framework for reconciliation of resource performance with grade control, mining actuals and mining schedules, and ultimately milling. As well as a means for analysing past performance through reconciliation, it has proven its worth as a predictor of variation and an input to successful schedule sequencing and change management. The IPM is a critical component of the TGM Mine Planning System, providing a centralised framework for short interval mill feed prediction through to life-of-mine (LOM) planning.Current development of the IPM is working towards incorporating Mine to Mill optimisation and real-time material tracking projects at TGM. If successful, the model will provide a truly powerful mine planning data source. Current development outlines a mechanism for tracking material from Mine to Mill, and for transferring mill performance data back to the IPM. Increasingly advanced material classification and mine planning, incorporating the multiple geometallurgical variables, will enable the mine to provide consistent mill feed products and result in a steady state and optimised mill.This paper outlines the vision, creation and benefits of the IPM at TGM. It also introduces the ongoing developments to ensure the IPM becomes only more relevant to successful and integrated mine planning as TGM matures from the new kid on the block to the old hand in the neighbourhood.CITATION:Catto, B, Elder, D, Edwards, R, Kent, M and Woodward, J, 2017. An integrated approach to mine planning – building the integrated planning model at Tropicana gold mine, in Proceedings Tenth International Mining Geology Conference 2017, pp 305–314 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By L H. G McClean

Environmental, social and governance (ESG) factors have always been important to the minerals industry and is now considered one of our most important opportunities (and risks). Getting it right from the beginning is critical for the minerals industry, and that starts with mineral exploration. Exploration, or the process of investigation of an economic mineral deposit, is generally low impact and short-term. Exploration operations vary in size and scale and often shift priority, focus and location relatively quickly. Australia is a highly regulated jurisdiction with different regulatory systems and requirements in every state and territory. Most mineral exploration is undertaken by junior exploration companies or ‘explorers’. Exploration companies are lean operations with limited staffing and resources, traditionally with no income apart from funds raised or work through partnerships. Funds are tight and administrative investment is minimised so that investment into activity on the ground is maximised. All these variables mean that understanding and implementation of ESG frameworks for an exploration company can be challenging. ESG is a fast-moving sector with currently multiple frameworks and reporting standards. Interest from community and government stakeholders as well as investors and off-take partners has been growing, with mandatory reporting soon to be implemented. The upcoming changes to the JORC Code will ensure that ESG considerations will be a key component of all public reporting. Resources have been developed to support explorers implement, manage and report on ESG considerations. Due to their scale, agility and direct importance of land access and social licence, many explorers are not the ‘cowboys’ (or ‘cowpersons’) of the industry, but industry leaders in ESG. Strong interest and leadership have led to innovative practices and strongly embedded vertical frameworks that directly contribute to social licence to operate.

Sep 1, 2024

This paper presents an overview of the strategy adopted to bring the Ballymoney opencut lignite deposit to an advanced stage of mine design and confidence. Certain aspects of the project differentiate it from the normal Australian experience. These include the thick overlying glacial drift, the proximity to established infrastructure and the wide fluctua- tions in annual lignite demand. The incorporation of these factors in the mine plan are discussed. The deposit area is located near the town of Ballymoney, in Northern Ireland. In July 1986, after winning an internationally competitive tender, Meekatharra Minerals Ltd commenced an exploration programme designed to delineate reserves to supply a 450 MW power station. In less than eighteen months, a complete evaluation was undertaken and a price submitted in December 1987 to the relevant authorities for the supply of lignite. Subsequently, UK government consultants and significant inter- national banks have endorsed the findings. The mining study commenced with the evaluation of various develop- ment strategies, followed by selection of the most viable mining method and equipment. The equipment selected will mine four million tonnes of lignite and eleven million cubic metres of waste each year. In year 15, the waste removal requirement increases to almost seventeen million cubic metres. This results in an average strip ratio over the mine life of three cubic metres of waste per tonne of lignite. The quality of the product delivered to the run of mine conveyor transfer point, based on maximum resource recovery, will include heat content of 8813 kJ/kg (3789 Btu/Ib), ash content of 28% and moisture content of 40%.

Jan 1, 1989

By R Castedo, P Segarra, L M. López, J A. Sanchidrián, A P. Santos

The cylinder test allows us to determine the expansion of a copper cylinder by the detonation of an explosive charge inside. This test, originally designed for military explosives, has been adapted for industrial explosives with non-ideal behaviour. From data obtained with this test and known physical relationships, an analytical procedure has been developed to calculate the Jones-Wilkins-Lee (JWL) equation of state parameters for five ammonium nitrate/fuel oil (ANFO) and six emulsion-type explosives. A new radial wall expansion function is proposed considering a non-zero initial velocity with the consequent positive Gurney energy at unit relative volume. A set of equations is established to determine the JWL parameters, three of them obtained at the Chapman-Jouguet (CJ) point and the other three at different relative volumes. These equations, along with some constraints to ensure a physically sound solution, are solved for the JWL parameters by a non-linear least squares scheme. A 2D Lagrangian axisymmetric finite elements (FE) numerical model is developed for each tested explosive to validate the analytical results, in terms of expansion histories, with good agreement. This confirms that the set of conditions, constraints on the parameters and least squares calculation used constitute a robust methodology that fully captures the physics of the detonation products expansion involved in the cylinder test.CITATION:Castedo, R, Sanchidrián, J A, López, L M, Segarra, P and Santos, A P, 2015. Jones-Wilkins-Lee parameters for civil explosives, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 57–64 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By P J. Sack, L V Danyushevsky

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Regional-scale exploration for sediment-hosted gold deposits is hampered by the challenge of evaluating the fertility of ancient sedimentary sequences that host these deposits. Recent developments in laser ablation inductively coupled plasma mass spectrometry allow for the evaluation of the gold fertility of sedimentary sequences using chemistry of early-formed sedimentary pyrite. We present a case study from the Selwyn basin area of Yukon, Canada, where significant sediment-hosted gold exploration has been ongoing for the last five years. Data from sedimentary pyrite in some Neoproterozoic shales are anomalous in Au and As compared to a global data set of unmineralised sedimentary pyrite. If at least some of the gold and associated trace elements in sediment-hosted gold deposits are derived from recrystallisation of early sedimentary pyrite, it follows that strata containing anomalous sedimentary pyrite should be more prospective. Based on this premise, our data clearly show that Yusezyu Formation Neoproterozoic shales in the Selwyn basin area of Yukon are a fertile source rock for sediment-hosted gold deposits, while pyrite from Nadaleen formation shales are strongly anomalous in Hg and Tl, but not Au. We suggest that the area warrants continued exploration for sediment-hosted gold.CITATION:Sack, P J, Gregory, D D, Large, R R and Danyushevsky, L V, 2015. Using sedimentary pyrite chemistry to inform regional exploration for sediment-hosted gold deposits – a gold fertility case study from the Selwyn basin area, Yukon , in Proceedings PACRIM 2015 Congress, pp 69–76 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By G Bignall, I Chambefort, A B. Christie, A J. Rae, M P. Simpson

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Key indicator hydrothermal alteration minerals formed from fluids of known fluid composition (neutral versus acid pH) and temperature have been mapped for New Zealand (NZ) geothermal fields by visible/near-infrared (VNIR) and short wave infrared (SWIR) reflectance spectroscopy. Smectite, interstratified illite-smectite and illite formed from neutral pH fluids have zoned distributions with higher temperature illite (>220ºC) in and around the upflow of chloride waters and low temperature smectite (<150ºC) on the margins (eg Ohaaki, NZ). In adularia-sericite epithermal deposits, Au-Ag veins are similarly surrounded by zoned clays, with mineralised veins enclosed by illite (eg Martha, NZ) or occurring at the illite/illite-smectite boundary (eg Favona, NZ). Reflectance spectroscopy is also highly effective in identifying minerals formed from acid fluids; both steam-heated acid-sulfate waters (eg kaolinite and alunite at Rotokawa, NZ), or magmatic-hydrothermal fluids (eg pyrophyllite and topaz at Ngatamariki, NZ). These same alteration minerals commonly show zoned distributions in high sulfidation epithermal deposits (eg Rodalquilar, Spain) and in lithocaps associated with porphyry deposits (eg Lepanto, Philippines). Thus reflectance spectroscopy permits the rapid identification of key alteration minerals that can be mapped at a high sample frequency and used as vectors towards mineralisation.CITATION:Simpson, M P, Bignall, G, Rae, A J, Christie, A B and Chambefort, I, 2015. Mapping hydrothermal minerals in New Zealand geothermal fields using reflectance spectroscopy (VNIR-SWIR) and application to mineral deposit exploration , in Proceedings PACRIM 2015 Congress, pp 243–248 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By A Turichshev

The synthetic rock mass (SRM) approach for modelling jointed and veined rock has been at the forefront of caving geomechanics research for years. A well-constructed and calibrated SRM model can capture the full rock behaviour at a macroscopic scale. Traditionally, SRM technology employed bonded particle models (BPM) due to their ability to model rock’s response to loading without prior specification of behaviour. The SRM modelling process requires the BPM to simulate intact rock and the subsequent introduction of fractures or veins by changing bonding characteristics between the particles. However, bonded particle materials have difficulty reproducing both the compressive and tensile strengths of intact rock. This and other limitations of BPM have been the driving force in exploring the potential of grain-based (2D) and bonded block (3D) models (BBM).This paper reports on recent work exploring the applicability of both BPMs and BBMs in 3D to the modelling of intact rock. The advantages and limitations of both BPMs and BBMs are addressed based on the results of numerical simulations using the PFC3D and 3DEC distinct element codes. The preliminary results suggest that BBMs are better suited for simulating intact rock behaviour than BPMs. Ongoing work aims to better qualify the applicability of BBMs under different conditions. This has significant implications for our understanding of rock mass behaviour in a caving environment.CITATION:Turichshev, A and Hadjigeorgiou, J, 2016. Simulating intact rock behaviour using bonded particle and bonded block models, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 453–460 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By J Kok

"In some underground mines it has been observed that the primary focus during feasibility studies is to determine the best way to mine the defined orebody. Some studies have been conducted without sufficient consideration of the ventilation and cooling requirements or the risk from exposure to associated airborne pollutants caused by the mining operations.Following the hierarchy of control to manage risk, numerous problems of the ventilation systems in some underground mines could have been avoided if sufficient consideration was given to the ventilation requirements to manage heat, airborne pollutants and leakage during the feasibility study phase. If the constraints and hazards were well defined and understood at the time of the study, efforts could have been made to eliminate or substitute the hazards to decrease the risk. Some of these problems include but are not limited to: primary fan locations heat loads diesel exhaust ventilation design based on the production requirement fire/emergency response strategies.This paper highlights areas in the ventilation discipline that are sometimes overlooked during feasibility studies. It will also highlight the importance of the Ventilation Specialist during these studies. Experience and knowledge of best ventilation practices must be applied in feasibility studies.As a result of adequate consideration to all ventilation aspects in the feasibility study phase, risks will become lower in terms of health, safety, production loss and equipment downtime caused by heat.CITATION:Kok, J, 2014. Feasibility studies – what should be considered in terms of ventilation, in Proceedings 12th AusIMM Underground Operators’ Conference 2014, pp 197–204 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 24, 2014

By E Vargas, A Egana, M Alarcon, X Emery, A Barberan, A Lopez, N Morales, C Friedrich

"As the cost in time and money of data from sensors and small-scale tests has reduced, additional challenges have arisen. Although many mine data sets are not big relative to those in other disciplines, they are complex in other ways, and becoming too large to manage efficiently on personal computers. In order to take advantage of the opportunity offered by increased data, a diverse team from Universidad de Chile and CSIRO Mineral Resources has developed a virtual geometallurgical laboratory to support the computational requirements linking data acquisition with data-driven business decisions. A particular focus to date has been the development of user-guided workflow ensembles to enable comparison between plausible geometallurgical hypotheses.A case study has been undertaken using publicly available data from the Rocklea Dome iron deposit in Western Australia. A hypothetical mining schedule was produced from geochemical and hyperspectral drill core/chips data via the following steps: data preprocessing, exploratory data analysis, geochemical interpolation, block modelling, ultimate open pit design and scheduling. The key outcome of this study was the integration of workflow stages through new plug-in methods or modification of existing software. Outcomes from this study will be described in the paper in terms of geological and metallurgical data quality, analytical software support and ongoing computing infrastructure requirements.CITATION:Lopez, A, Barberan, A, Alarcon, M, Vargas, E, Ortiz, J, Morales, N, Emery, X, Egana, A, McFarlane, A and Friedrich, C, 2016. Progress towards Data-driven Mine Planning via a Virtual Geometallurgical Laboratory, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 287–294 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By Y Peng, D J. Bradshaw, X Chen

At NewcrestÆs Telfer gold mine, a strategy of regrinding pyrite rougher flotation concentrates has been proposed to increase gold recovery and reduce cyanide consumption in the CIL circuit. The regrinding will be followed by an additional copper/gold flotation stage, where copper minerals need to be separated from pyrite. However, although the minerals are well liberated, the separation of chalcopyrite from pyrite in the cleaner stage is not always straightforward. The surfaces of the fine particles, produced during regrinding, are more easily oxidised and contaminated than coarse particles, directly influencing the particle floatability. The depression of pyrite is difficult in the cleaner stage as well due to copper activation, a process which is also highly dependent on the grinding environment. In this study, different grinding media, including mild steel and stainless steel, was used in the regrinding to produce different regrinding chemistry, such as, pH, Eh, and iron hydroxide contamination. The effects of regrinding conditions on chalcopyrite flotation and its separation from pyrite were studied. It was found that the stainless steel grinding media, which produced an oxidising environment, was more beneficial for the separation of chalcopyrite from pyrite after regrinding. The mild steel grinding media had a detrimental effect on both chalcopyrite and pyrite flotation. This study addresses the importance of choosing suitable regrinding conditions in the pyrite and copper flotation circuit.CITATION:Chen, X, Peng, Y and Bradshaw, D J, 2012. Effect of regrinding conditions on the flotation of chalcopyrite and its separation from pyrite in the cleaner stage, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 279-286 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By Mernagh T, Large R. R, Ryan C. G, Huston D. L

The Tennant Creek goldfield is one of the largest gold producing districts in Australia, and major deposits, including Gecko, Juno, Orlando, Peko, Warrego, Nobles Nob, Golden Forty, Argo, TC 8 and White Devil have produced more than four million ounces of gold over the past two decades. Gold-copper-bismuth mineralisation at Tennant Creek occurs in lenticular, ellipsoidal or pipe-like bodies of magnetite-hematite ironstones which are hosted in turbiditic sedimentary rocks of Proterozoic age (Large, 1975; Wedekind, Large and Williams, 1989; Le Messurier, Williams and Blake, 1990; Morrison, Donnellan and Hussey, 1992).

Jan 1, 1994

By D Reid

Run-out analyses of tailings storage facilities are typically undertaken using methods based on rheological theory. These are reasonable techniques to model the behaviour of tailings that, through significant run-out and possibly mixing with supernatant water, are generally acting in a fluidised manner. Such modelling often follows on from two-dimensional continuum analysis models where, if failure is predicted, grid failure often occurs when deformations begin to increase. This results in a disconnect between the prediction of failure and the modelling of the potential extent of the failure.Recently, rezoning methods have been incorporated into commercially available two-dimensional soil mechanics deformation codes. Rezoning techniques enable large deformations to be modelled within a two-dimensional continuum analysis framework; however, while promising, the use of such tools is not yet widespread, and a consensus is yet to develop on how they should be applied to tailings dam run-out modelling.This paper uses FLAC rezoning techniques to model the flow behaviour of two historic tailings dam failures. The purpose of these analyses is to critically assess the performance of rezoning against some available historic failures. The required data to undertake such an analysis is outlined, along with the inherent limitations and assumptions required. Parametric analyses are outlined to address some of these issues. In general, the analyses undertaken underestimated the flow distance observed in the historic failures by varying degrees; however, in some instances, the analysis reasonably reproduced the qualitative shape of the initial failure zone. A variety of potential reasons for the discrepancy between historical observations and the models undertaken are provided.CITATION:Reid, D, 2015. The use of rezoning techniques to model historic tailings failures, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 201–206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By J Rock, K Bambrook

"Hanwha Mining Services was approached by Glencore Coal to provide a series of (trial) demonstration blasts at its Clermont coalmine. The intent of the project was to trial a bulk explosive product that would be able to provide sufficient energy for the ground type encountered without production of post-blast fume. Three blasts were loaded using the patented XLOAD bulk explosives with a density of 1.00 g/cc. XLOAD bulk products are water resistant explosives that can be loaded at densities much lower than traditional (generic) water resistant heavy ammonium nitrate – fuel oil (ANFO) or pumped blends with significantly reduced risk of fume. In addition, these products have detonation characteristics that generally deliver a higher heave partition than conventional bulk products and hence improve muck pile looseness and digability.The priority key performance measures included the absence of fume from blasting, being at least cost neutral and providing similar if not improved shovel dig rates. The design for the initial blast took a conservative approach to ensure the key blast outcomes of fume control and fragmentation were achieved.The second blast used the same pattern dimensions as the benchmark bulk product used in this area to provide a cost neutral comparison with the benchmark products that had been used over the prior six months. This resulted in a 20 per cent lower powder factor than would have otherwise been used. To test the suitability of XLOAD, this shot was slept for over two weeks between loading and firing in geology where the sleep time is typically kept to a few days to minimise the fume risk.The third blast utilised a slightly larger drill pattern to push the capabilities of XLOAD and provide a cost neutral comparison between the trial product and the traditional benchmark products. All three blasts were fired with no fume observed, no recordable incidents and good fragmentation. Shovel productivity from all three of the trial blasts was excellent with higher average instantaneous dig rates being recorded (average six per cent improvement against the instantaneous dig rates recorded for the benchmark blasts).Citation:Rock, J and Bambrook, K, 2016. Controlling Blast Related Fumes with Unconventional Explosives, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 39–49 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By P F. Hodkiewicz, J de Lacey, M Stewart, R Lane

"Implicit modelling is an approach to spatial modelling in which the distribution of a target variable is described by a unique mathematical function that is derived directly from the underlying data and high-level parametric controls specified by the user. This modelling approach may be applied to discrete variables such as lithology (after converting the discrete codes to numeric values) or to continuous variables such as geochemical grades. This paper discusses the estimation of continuous (grade) variables using implicit modelling.One of the underlying engines of implicit modelling for producing this mathematical function description is the radial basis function (RBF). In essence, the RBF is a weighted sum of functions positioned on each data point. A system of linear equations is solved to derive weights and the coefficients of any underlying drift model coefficients. Once derived, the RBF may be solved for any unsampled point or averaged over any volume to provide an estimate of grade. It is possible, for example, to query the RBF on a regular grid to derive an estimate of block grades. Given the ease of creation of an RBF, and its ability to predict grade, the question arises as to how the grades derived from the solution of an RBF compare with grade estimates derived from conventional geostatistical interpolation methods (eg ordinary kriging (OK)).The purpose of this paper is to describe in lay terms: the basic structure of an RBF the role of parametric choice in the solution of RBFs and how this influences the character of the solution the fundamental similarities and differences between RBFs and conventional geostatistical estimators.Using a high-resolution conditional simulation, we show that in many situations RBF and OK estimates are very similar.CITATION:Stewart, M, de Lacey, J, Hodkiewicz, P F and Lane, R, 2014. Grade estimation from radial basis functions – how does it compare with conventional geostatistical estimation?, in Proceedings Ninth International Mining Geology Conference 2014 , pp 129–140 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 18, 2014

By S Dykes, R J. McCarthy, B Klein

There is growing interest in the mining industry on the application of ore sorting. While many are familiar with particle sorting, including the limitations that technology presents (e.g. throughput), bulk sorting, with its higher throughput potential, is less understood. Despite the potential to sort at higher throughputs, few operations have adopted bulk sorting processes, certainly not at large scale. It is suggested that the inability to reliably predict outcomes from bulk sorting may be limiting its adoption in mining projects. Consequently, an evaluation approach for bulk ore sorting has been developed such that mass pulls and grade upgrades can be predicted in the context of a mining study. The approach allows for evaluation of drill core assays and application of the consequently derived heterogeneity relationships to the block model for estimation of sorting outcomes. These processes were applied to conveyor-based bulk sorting for the CuMo project in Idaho, USA and are described in this paper.

Nov 10, 2020