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By S H. Begg

"*This is an abstract only*Most technical and economic analyses are performed to reduce uncertainty to help make decisions. Decision-making is about ranking alternatives - rarely are precise predictions required, if even possible. This simple observation has profound implications for modelling approaches, how they deal with uncertainty and the reliability of information provided by subject matter experts.CITATION:Begg, S H, 2013. Some reflections on uncertainty, decisions, models and people, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013, pp 3-6 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 29, 2013

By Newell RB

Grinding circuits are used in most mineral processing plants. Their widespread application makes the efficient running of the circuits essential to almost all resource projects. This paper will show that, with the application of modern multivariable control techniques, improved plant performance can be obtained when compared with conventional single loop control strategies. Results are presented for a simulated closed-circuit ball mill.The grinding circuit was controlled using the rod-mill water and primary and secondary sump dilution flowrates as the manipulated variables. Variables controlled were the primary cyclone feed flowrate, the primary cyclone feed density and the particle-size measurement (percentage smaller than 75 um).

Jan 1, 1985

By K S. Park, J K. Kim, J H. Park, Y Su

The present study investigates the possibility of the direct removal of oxygen from the Ti-30Ni (wt per cent) alloy melt through the thermodynamic equilibrium reactions at 1623 K in the vertical tube furnace. The deoxidation efficiency of Ti-Ni alloy melt by adding different contents of metallic calcium (Ca) as a deoxidant was evaluated with the binary CaF2-MgCl2 flux. The thermodynamic equilibrium experiments showed that the total oxygen content in the alloy decreased from about 650 ppm to 350 ppm when 3.5 wt per cent Ca was added to the Ti-30Ni (wt per cent) alloy. Alternatively, the effect of flux composition in the CaF2-MgCl2 flux on the oxygen content was also investigated at 1623 K. Therefore, the effect of binary flux systems on the deoxidation ability was compared at 1623 K. According to the results, the flux system with 80 per centCaF2– 20 per centMgCl2 exhibited the best deoxidation capability, ie total oxygen content in the alloy reduced from 1450 to 550 ppm.

Aug 21, 2024

By Barro L

Very large reserves of gas are contained in coal. Because of the low permeability of the coal gas flow rates are very low. Fracturing of the coal can be achieved by use of the nitrogen - foam frac techniques described but the flow rates after fracturing are not sufficient to support economic development. Fracturing of the seams in the Bowen Basin was as predicted but in the Sydney Basin no trace of the fracture could be found when development proceeded past the fractured well. Testing of coal samples has provided some insight into parameters affecting desorption Rates.

Jan 1, 1982

By Johns AS

Comissioning of a new residue disposal tcluding upgraded classification for none backfill preparation, new variable speed pumps and a new residue dam took place in 1¦76. The system is described.

Jan 1, 1978

By M Mee, R L. Gwyther

Accurate measurement of rock mass response during the mining of massive underground orebodies is essential, as mines become larger and deeper. These measurements enable: provision of quantitative data for optimal pit slope design and engineering; monitoring of the stability of deep pit slopes, the long-term integrity of shafts and large-scale underground infrastructure, and long-term measurements of deformation or rock mass creep following the mining process for environmental management. Strainmeters traditionally used for deformation measurement have neither the long-term stability nor the high sensitivity to perform measurements in these applications. This paper describes a new precision borehole strain monitoring system (GTS) currently deployed by CSIRO Exploration and Mining, which has the potential to solve these new issues in rock mass deformation monitoring. This technology was originally developed for use in hard rock mines (Gladwin, 1977) and refined considerably for earthquake research (Gladwin et al, 1994; Gwyther et al, 1992). A case study of the use of the GTS in monitoring longwall coal mining over the period 1993 - 1998 is presented.

Jan 1, 2000

Energy is central to respond to critical stakes on human and industrial development requirements as well as on climate change. The increase of the share of carbon-free energy sources in the global supply mix will help to reduce significantly greenhouse gas emissions (GHG) as power generation accounts currently for 41 per cent of these emissions from the energy sector. In this energetic mix, nuclear and renewable energies are complementary, the first more focused in the baseload power generation whilst the second is well suited for decentralised power generation. In this context, AREVA's goal is to enable everyone to have access to a cleaner, safer and more economical energy. Regarding nuclear energy, AREVA's strategy is to capitalise on its integrated operation model, which groups together fuel cycle and nuclear power plant construction, aiming at building one third of the new nuclear capacities and securing the fuel cycle supply chain for its existing and future customers. Therefore, the front end of the uranium fuel cycle, from mining to the fabrication of fuel assemblies, has a key role in the sustainability of the nuclear industry. The replacement of the current capacity and the entrance of new countries on the nuclear power generation might lead to a significant rise of uranium demand by 2020. In order to be prepared in time, AREVA defined an ambitious industrial program to expand mineral reserves, increase the production of uranium concentrates, replace the conversion capacity, build two new uranium enrichment plants, one in France and one in the United States and upgrade its fuel manufacturing plants. To support the front-end industrial activities in the short and long term, AREVA invests on a portfolio of R&D projects to find out solutions to meet customers' needs, to improve its competitiveness and to develop new concepts and solutions to anticipate future market evolutions. In particular, some important technological challenges in mining must be surmounted to develop cost-effective methods to explore and exploit low grade deposits while creating sustainable solutions for reducing reagent, water and energy consumptions. In this lecture, an overview of the industrial investments of AREVA in the front end of the uranium fuel cycle and some highlights on its R&D major axis will be presented. This is an abstract only. No full paper was prepared for this abstract.  

Sep 13, 2010

By Mez W

the German ruining industry uses different residues for hackfilling and stowing. A hydraulic pipe conveying technology for these materials has shown advantages for the transportation into the mine. Pipeline conveying systems are able to bridge long distances, they save room within the underground workings and they save staff and costs. Absolutely necessary for successful use of the hydraulic conveying technology is the knowledge about the unusual non-Newtonian flow properties of solid/liquid mixtures like pastes and slurries. The flow resistance of these materials cannot be described easily by one viscosity. Owing to a yield point and a pseudo-plastic behaviour the viscosity changes with the shear rate and with the streaming velocity inside the pipe. Also these flow behaviours depend very sensitively on the liquid/solid-ratio, often so dramatically that gravimetric or volumetric dosing equipment is not in a position to control the production of backfill pastes. Quality changes of the solid raw materials (particle size distribution, density, mineralogical composition) lead to additional difficulties. The first experiences with hydraulic backfilling plants were troubled by plugged pipes. a bad backfill quality caused by unnecessarily high water content and high costs for chemical binders to solidify the backfill. The installation of viscosity controlled paste production leads to success with the hydraulic backfill technology. A development of the l)MT, a bypass pipe-viscometer, has been the key technology. The system is able to analyse on-line, difficult, sticky and abrasive substances and determine their non-Newtonian flow properties. Because the system measures real physical values it is in a position to pre-calculate process relevant parameters like the pressure drop of the backfilling paste in the conveying pipeline. Newer types of the viscometer system also measure the slurry density and calculate its composition. These systems have proven a success controlling backfill paste production plants. They offer it secure prevention of pipeline plugging and a production of high quality backfill pastes with a water content as low as possible.

Jan 1, 1998

By M Kuruppu, B Besa

Currently, conventional methods of decline development put enormous cost pressure on the profitability of mining operations. This is the case with narrow vein orebodies where current methods and mine design of decline development may be too expensive to support economic extraction of the ore. The time it takes to drill, clean and blast an end in conventional decline development can be up to 473 minutes. This is because, once an end is blasted, cleaning should first be completed before drilling can commence, resulting in low advance rates per shift. Improvements in advance rates during decline development can be achieved by application of the electric monorail transport system (EMTS) based drilling system. The system is composed of a two-boom drill mounted on the monorail and a pneumatic face cleaning system that loads blasted material into monorail containers. The operation allows for drilling of the top part of the face to commence as the monorail loading system continues to clean the blasted material at the development face. The preliminary indication is that an advance rate of 12 m per day could be achieved compared to 6 m per day in conventional decline development. The increase in the advance rate results from increased number of blasts that are possible per shift due to reduced time of cleaning and drilling the development face. The continuous drilling system has the advantage of accelerated decline development and orebodies will be accessed quickly and cheaply. Other advantages of the system include negotiating steep and changing gradients (ie reducing decline length), ability to negotiate tight horizontal curves, small operating room and limited diesel fumes.

Jan 1, 2008

By G S. Esterhuizen, M M. Murphy, T S. Bajpayee

The strength reduction method (SRM) has been implemented in the FLAC3D finite difference software and applied to coalmine entry support evaluations. The FLAC3D numerical models have been calibrated against instrumented field sites in varying geologies, depths and field stress conditions. The calibration between the field and model results obtained a satisfactory match for rock deformation and support response. Previous research has also developed good correlations between numerical model stability estimations using the SRM and empirically derived stability estimations using the analysis of roof bolt systems (ARBS) software and the coalmine roof rating (CMRR). The purpose of this paper is to further apply the SRM to investigate how specific geotechnical and support parameters can impact coalmine entry stability. Results from different studies demonstrate how the calibrated models were used to investigate a few of the well-known questions in both mine design and support design. For mine design the impact of strong and weak beds in the roof strata, rotating the principal stresses and weakening the floor on excavation stability is investigated. For support design the impact of support length, support spacing and adding cable bolts to the design is demonstrated. These scenarios are evaluated in developmental coalmine entries for a variety of geology and field stress conditions. Stability factors are calculated for each scenario using the SRM. The SRM allows the impact of each parameter to be quantified and allows the support system to be optimised for given geotechnical conditions.CITATION:Esterhuizen, G S, Murphy, M M and Bajpayee, T S, 2014. Analysis of geotechnical and support parameters on coalmine entry stability using the strength reduction method, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 383–392 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By M Araos, I Onederra

A novel explosive formulation that substitutes the use of ammonium nitrate (AN) with hydrogen peroxide (HP) as the main oxidising agent has been developed and tested as part of an Australian Coal Industry Research Program (ACARP) project. The main objective was to provide a step-change solution that has the potential to completely eliminate NOx fumes in blasting. The development of this HP/fuel-based explosive started with a comprehensive detonation characterisation program, consisting of unconfined velocity of detonation (VOD) measurements of samples at different diameters, densities and void sensitisation techniques. VOD results showed that the HP/fuel-based explosive mixtures behaved similarly to non-ideal commercial explosives; in that way mixtures could be tailored to achieve specific detonation performance targets. The next stage of testing in this development involved preliminary confined tests to evaluate the rock breakage potential of the HP/fuel-based explosive mixtures. Fully instrumented single-hole tests were conducted in a limestone quarry. Results from these preliminary trials confirmed the rock breakage performance of HP/fuel-based explosive mixtures. The confined VOD measured in one of the tests was 5100 m/s in a 102 mm diameter blasthole at a density of 0.96 g/ml. The corresponding borehole pressure measurement of this HP charge was 2.61 GPa with a detonation temperature of 2921°C. Based on near-field accelerations, both HP and ANFO charges displayed similar attenuation characteristics in the test conditions. Post-blast observations indicated that the breakage performance of the HP mixtures clearly reflected the in-hole detonation performance measurements obtained, confirming the ability of these explosive mixtures to both fragment and effectively displace the rock mass under evaluation. Further research work continues with the future commissioning of a prototype mixing and delivery unit, the successful completion and analysis of data from multiple-hole trials, and further characterisation work associated with product stability, reliability and performance under different geotechnical conditions.CITATION:Onederra, I and Araos, M, 2015. Detonation and breakage performance of a hydrogen peroxide-based explosive formulation, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 565–574 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By B McFadyen, Y Potvin, K Woodward

The Australian Centre for Geomechanics (ACG) held two workshops in 2019—one in Australia and one in Canada—to discuss processes and methods currently used in the mining industry for stope design and reconciliation. In practice, this work strives to optimise stope performance and aims to maximise ore recovery (minimise underbreak), while minimising dilution (overbreak). One of the key findings from the workshops was that current stope design practices, almost exclusively, rely on some versions of the empirical Stability Graph methods developed in 1980s. Although robust and useful at the feasibility study stage, there are a number of inherent shortcomings with this approach. The Stability Graph’s limitations first lie in that it cannot assess underbreak, which is a very important measure of performance. Furthermore, the method doesn’t consider a number of factors which often have a critical influence on stope stability, for example, drilling and blasting or the presence of faults. Given the current industry standard practice, there is a great opportunity to reinvent the stope design process to optimise performance. A finding of the workshops was that every mine quantifies stope performance in terms of volume reconciliation with a focus on dilution and ore losses, and reconciling metal tonnes recovered from the mill. Many mines further investigate stope performance by looking at individual stope faces and the causes for the deviations between the planned stope shape and the measured cavity. Recent research at the ACG has shown that investigating overbreak and underbreak at a higher resolution is a powerful way to identify the root causes of overbreak and underbreak. Finer scale assessment is achieved using an octree analyses, which effectively divides the relevant stope volume into cubes on the scale of a metre and produces many tens of thousands of data points. The octree data structure and subsequent analysis underpins a data-driven stope design methodology. The ACG is currently developing a design approach based on multivariate modelling methods that can account for the many variables that influence stope performance and forecast stope overbreak and underbreak results. Back-analysing stopes based on octree reconciliation results provides a rich database for training the model. Once the model can achieve reliable forecasting of overbreak and underbreak, an interactive drill-and-blast design will allow for the assessment of different firing strategies to optimise stope performance.

Mar 15, 2021

By K Williams, T Donohue, W Chen, T Roessler, A Katterfeld

Wet sticky iron ore poses particular difficulties in every aspect of the material handling process. Material hang-ups in bins, pipes and chutes; carry-back and spillage due to insufficient belt cleaning; clogging of screens; malfunctioning of crushers as well as rat holing of gravity reclaimed stockpiles are all predominantly due to the inherent cohesion and adhesion characteristics of the wet, sticky ore (Roberts, 1993). Limited understanding and quantitative measures on the stickiness of such a material significantly lower the mining operation efficiency.This research aims to investigate the cohesion and adhesion characteristics of the wet, sticky ore on physical modelling, experimental techniques and numerical implementation. Initially, the suitable bridging mechanism that contributes to the cohesive and adhesive forces within the iron ore material was identified (Hering, Martin and Stohrer, 1989; Rumpf, 1958). A cohesion/adhesion energy density factor based contact model was then introduced to describe the stickiness of the material. Secondly, an experimental system was proposed to directly test the stickiness of the material. Such a system is able to obtain both the cohesive/adhesive shear force and tensile force of the material at a specific moisture content. Lastly, the implementation of the proposed cohesion/adhesion model into the discrete element modelling (DEM) software was also discussed. A cohesion/adhesion calibration for modelling wet sticky iron ore in DEM was then conducted to ensure the material modelled in the simulation is reflective of the reality.From the study, understanding of the cohesion/adhesion characteristics of the wet iron ore material is significantly enhanced. Experimental and numerical outcomes can be directly applied for better designing or optimising the material handling processes that involve wet sticky iron ore. Consequently, the mining operating costs can be greatly reduced.CITATION:Chen, W, Donohue, T, Williams, K, Katterfeld, A and Roessler, T, 2015. Modelling cohesion and adhesion of wet, sticky iron ores in discrete element modelling for material handling processes, in Proceedings Iron Ore 2015, pp 387–392 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

Exploration for uranium in Australia has so far discovered reserves equal to 17.5% of the Western World's. The Australian uranium industry, when fully developed, will be one of the largest producers and possibly the largest exporter in the world. The world's nuclear industry is young, rapidly developing in size and technology and is subject to more social, political and regulatory controls than any other industry. This paper considers the probable development of Australia's uranium industry against a background of normal commercial parameters together with other factors which are peculiar to the nuclear industry. As the theme of this conference is "Australia's role in the World Mineral Indus- try" this paper concentrates on the commercial and practical aspects associated with the development of Australia's uranium resources in a world context.

Jan 1, 1979

The success of any industry depends on the planned integration of the policies and resources of the key components of the Australian economic and political structure - government, industry management, education, research, and the human resources of the industry. The Australian Mineral Industry, like Australia itself, has grown and developed at a rate not foreseen by many of our founding fathers and early industry leaders. Hence, now, as we approach the 21st Century, we need to re-think our approach to the significant new problems that are beginning to face both government and the Mineral Industry. Government initiatives, government information and support services, industry re-structuring, and research and development support, need to be carefully re-evaluated, re-diredted,. and strengthened, so that government, the community, and the Mineral Industry produce and receive the optimum education and research strategies and services. The support of academics and researchers, the development of facilities, and the design of new Courses for the future successful and beneficial exploitation of minerals need particular consideration.

Jan 1, 1986

The ores described in this paper are from the two principal orebodies at Wiseman's Creek, a small village about 22 miles south-east of Bathurst in central-western New South Wales.The first official reference to mining at Wiseman's Creek is in "Mineral Statistics of New South Wales" of 1875, which reported that the Wiseman's Creek Copper Mining Company had proved a lode-later known as "North Wiseman's"-to a depth of 120 ft., where it was found to be 20 ft. wide. By 1876 the erection of a mill and smelting works had commenced, and the sulphide ore found to contain copper lead, zinc, silver and gold. Some oxidised ore was also being worked. Operations were, however, generally unsuccessful, and sporadic work up until 1907 produced only about 5,000 tons of ore. The other more important orebody of the locality-the Phoenix-was not opened until about 1895. By 1908, as reported by J. E. Carne, the shaft had been sunk 340 ft., with the extraction of both oxidised and primary ore. At the time of the slump in copper, pric'es in 1907 approximately 3,000 tons of, ore had been produced.Several smaller orebodies were discovered and worked during the same period as the North Wiseman's and Phoenix, but their output was more or less insignficant. THE OREBODIES AND THEIR GEOLOGICAL SETTINGIt is now impossible to examine the orebodies underground, but they appear to have formed a series of flat lenses, whose major axes were parallel to ,the foliation of the enclosing quartz-chlorite-muscovite schists. The largest ,of these lenses was worked as the North Wiseman's orebody, which was reported by Carne to vary in width from 1 ft. to 20 ft., and which probably extended discontinuously over a strike length of about 1,000 ft. The Phoenix orebody is stated to have varied from 1 ft. 6 in. to 3 ft. in width...

Jan 1, 1955

By W A. van der Westhuizen

Selective mining played a major role in saving a mine and a communityÆs existence as well as creating a working culture that is the model for all KumbaÆs mines. The successes that resulted from selective mining led to receiving KumbaÆs highest award (it was the Gold Medal Breakthrough project of 2003) as well as the productivity award at the National Productivity Institute award ceremony in 2004. Kumba was established in November 2001 (previously Iscor Mining). The new company identified Mineral Resource Management (MRM) as one of its key drivers and an initiative was launched to define MRM in the Kumba way. Best MRM practices at the Kumba mines were included in the definition. Selective mining was born out of this initiative. One of the key principles of good MRM practice was identified as: æThere must be a balance in the operational processÆ. This principle was applied with great success at Thabazimbi Iron Ore mine in the Limpopo province, South Africa. The emphasis of this paper will be to show how value can be unlocked throughout the whole mining value chain. In the past (up to 2001) the mine went through a number of crisis situations: planned production performances were not reached, the stripping ratio was extremely high with two new pits, the product beds were not of constant quality, slope failures were big risks, flooding could and did cut off half of the ore supply, and restructuring demoralised staff.This paper focuses on: selective mining throughput drivers, and selective mining and its role in achieving this balance.The results were dramatic, with huge improvements in production results, stockpiles, plant yields and product bed specifications. The mine was brought into balance and a self feeding loop was created with positive spin-offs up to this day.

Jan 1, 2005

By Foudoulis C, Smith CB, Drew RM, Sun S-S, Sheraton JW, Hall AE

Primay (syngenetic and protogenetic) inclusions - i.e. minerals formed during or before diamond growth and encapsulated in the diamond - provide important information on the origin of diamond. Recent Rb-Sr and Sm-Nd dating of such inclusions has yielded crystallization ages older than their volcanic host, implying that diamonds are mantle xenocrysts. In this paper we report results of studies on the nature of syngenetic inclusions and the carbon isotopic compositons of the host diamond from the West Australian diamond deposits at Argyle and Elllendale. The Argyle diamonds are dominantly, of eclogitic paragensis and are characterized by strongly C depleted compositions. We have recognized an association of stone morphology, inclusion type and carbon isotopic composition amongst the Argyle stones, and on the

Jan 1, 1989

By T Vizcarra, G Sandoval, C L. Evans

One of the challenges in the development of mineral processing simulators is modelling the liberation characteristics of particles produced by comminution circuits. Understanding the mineral characteristics of these particles is one of the keys to predicting their behaviour in separation circuits. While more fundamental research seeks to model the non-random breakage of ores this work examines whether we can move forward now by using observed characteristics of ores to model the composition of particles generated in comminution processes. Several researchers have noted the similarity of the liberation characteristics for a selected size fraction of particulate material, whether the fraction comes from a coarse material, such as the product from a jaw crusher, or a more finely ground material, such as the product from a ball mill. In most cases these observations were reported as an aside and were not the main focus of the published work. This observed behaviour has the potential to be a useful tool for modelling the particle characteristics in mineral comminution and separation circuits, particularly as we move towards the development of multi-component models. However, before the behaviour can be used widely we need to understand which ore types follow the observed pattern and which do not. The current work examines a range of ores and identifies which exhibit the pattern of similarity of composition for particles in a given size class that has been produced as the result of a variety of breakage conditions. The impact of mineralogy and texture on the evolution of liberation characteristics for both valuable and gangue minerals is discussed.

Jan 1, 2008

By Lyman GJ, Davis JJ

Models which have been presented in the literature consider only selected aspects of dense medium cyclone operation, are empirical in nature and generally relate only to severely limited ranges of operating parameters. This paper reports progress towards development of a more comprehensive and robust model. The data base consists of partitioning parameters developed using density tracers and conventional coal sampling and analysis techniques, together with recordings of parameters such as cyclone dimensions, feed pressure, medium size distribution and product media densities.. These data were drawn from 15 Australian coal preparation plants. To elucidate the effects of important operating parameters on medium behaviour and on the partitioning of large particles a series of pilot scale tests was also conducted. The present model consists of eight sub-models which relate to particular aspects of dense medium cyclone operation such as medium flowrates and densities, or size- by-size separation densities and Eps. The model structure follows a logical progression which clearly demonstrates the importance of understanding medium behaviour before attempting to predict partitioning performance. The model also attempts to define the conditions under which yield losses due to unstable "surging" discharge may occur.

Jan 1, 1987