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By J E. Everett, F Grobler

This study considers realistic data for a planned open pit iron ore mine, but is applicable to any open pit situation. By interpolating drill hole data, grades are generated for a rectangular block model. Each blockÆs grade designation vector has components for each analyte (chemical element or compound) influencing ore value. Interpolation by means of geostatistical kriging leads to each block being assigned its expected value, and thus underestimates the overall grade variability. Alternatively, interpolation by means of conditional simulation is a method that implements random sampling from an infinite population of solutions. Each conditional simulation has appropriate overall grade variability, but estimating any blockÆs mean and variance requires sampling from multiple conditional simulations. For a block model, an ore/waste selection criterion maximises the expected tonnage at a target grade. This criterion is a linear composite of the grade components, with positive coefficients for the beneficial analyte (iron) and negative coefficients for the deleterious analytes (such as silica, alumina and phosphorus).Although conditional simulation gives the same expected grade as kriging for each block, the expected maximum tonnage of ore selectable at a target grade may differ from that obtainable from the kriged solution. We apply the linear composite selection criterion to each of 25 conditional simulations, as well as to the kriged block model. The resulting distribution of product tonnage is confirmed to have an expected tonnage that is over 20 per cent greater than that of the kriged model. The method also enables a selection probability to be computed for each block, and thus a probabilistic pit boundary distribution to be identified and used in mine planning. Proposed extensions will consider risk-based scheduling of the multiple selection solutions through minimisation of a derived æstress factorÆ and treating the mining process as an iterative system with actual or artificial ædepletionsÆ modelled in line with the mine plan, using the updated state (with new information) to re-evaluate the mine plan for subsequent periods.CITATION:Everett, J E and Grobler, F, 2013. Risk-based ore selection from conditionally simulated block models, in Proceedings Iron Ore 2013 , pp 149-156 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By A Penney, M J. Pascoe, R M. Stephenson

The empirical McCracken and Stacey stability and risk assessment method has been in use for more than 20 years to assess geotechnical stability issues for raise bored shafts. The methodology has been applied with various levels of success. Increasingly, trends in mining and civil tunnelling have been towards larger diameter, single pass, raise bored shafts to rapidly provide means of ventilation, material movement (ore passes), or emergency egress. Identifying and assessing potentially problematic zones before raise boring commences can allow for appropriate risk-based decisions on construction, or to investigate alternative solutions. The implementation of a proactive solution to raising through an identified weak zone is preferred to the application of an engineered solution to an area subjected to substantial instability or failure. Methods for investigating potentially problematic areas are discussed in this paper based on AMC’s benchmarking data. Proactive investigation programmes resulting from these investigations are also discussed. Previous publications discussing the benchmarking data have concentrated on Australian case studies. Increased efforts and recent updates have been made to expand the database to include international case studies. This has provided further refinement of lower bound ‘raise bore rock quality index’ (QR) values, and various rock mass parameters for stability assessments. CITATION:Penney, A, Stephenson, R M and Pascoe, M J, 2018. Raise bore stability and risk assessment empirical database update, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 434–445 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By S J. Hawke, L A. Dominguez

In non-ferrous metal mining operations, it is generally necessary to crush and grind the ore to a very fine particle size to effectively liberate the contained mineral from the host rock. Fragmentation by blasting is the first stage of this comminution process.Numerous studies and independent modelling of the Mine to Mill process have demonstrated the potential for significant downstream productivity improvements from improved blast fragmentation. However, safety and environmental constraints associated with the blasting process usually limit the extent to which blast energy or powder factor can be increased.An effective blasting solution has been identified that enables the safe utilisation of powder factors several times higher than those used conventionally to provide significant improvements in fragmentation. The solution uses a static ‘blanket’ of broken rock overlying the blast to contain this increased blast energy and control rock movement. To produce this broken layer of rock, the subdrill in each blast is significantly increased to preblast (or precondition) the entire stemming region of subsequent blasts on the next mining bench.The solution has been evaluated at a large open cut poly-metallic mine in Mexico. Results from the application of this technique have shown significant improvement in run-of-mine fragmentation, with subsequent downstream productivity improvement indicated.CITATION:Hawke, S J and Dominguez, L A, 2015. A simple technique for using high energy in blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 321–326 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

Determining the controls of high-grade mineralisation at Vera Nancy requires careful data collection and assessment on a global and specific deposit basis. The techniques developed over 60 years ago to analyse structure, grade and width data are just as applicable today and can be enhanced using modern geological modelling software. High ore grades at Vera Nancy are controlled by both the primary geometry of the mineralised structure and the intersections of the main mineralised veins with subordinate splay veins. The main mineralised structure dilated as a consequence of extensional tectonics while the splays acted as conduits bringing oxidising surficial fluids into mixing zones precipitating high gold grades. Near-mine exploration is focussed on identifying zones of vein flexure and splay interaction to locate the relatively small high-grade shoots. Data modelling in a 3D environment is an essential process for understanding the geometry of the system being explored.

Jan 1, 2000

This is the seventh major symposium organised by Illawarra Branch over the past five years and the fifth dealing with various aspects of coal. It is clear that all of you here need no convincing that black is beautiful! This symposium is on a broader canvas, covering the overall field of occurrence, preparation and utilization of black coal throughout Australia. It is thus the most comprehensive treatment of the subject by the Institute since the symposium organized in 1950 by the Sydney Branch with the co-operation of the then newly formed branches in Newcastle, Illawarra, Central Western N.S.W. and Southern Queensland, all of which shared coal as a major interest. The 1950 symposium was adopted as a volume in the series of seven published by the Fifth Empire Mining and Metallurgical Congress in 1953. This historical reminiscence brings to our minds the circumstances in which these new Institute branches were formed. This happened in the year of the presidency of the late Frank Hockey, and at the time the Australian black coal industry was in many ways at a very low ebb. It was the time of extreme shortage of coal following World War II, and the industry was beset by industrial unrest on such a scale that daily bulletins were posted listing the number of idle pits, of idle miners and of tons of lost production. There could not, of course, be any thought of export marketing. Some of the more picturesque bulletins recorded the number of pits at which the ceremonial emptying of billies took place, and the number of pits at which the aroma of the horses' breath was insupportable. At an Institute conference at the time it is on record that the late lamented Austin Edwards, that tireless mineral researcher, author and editor, in his gentle way chided the personnel of the industry and the members of the Institute for having allowed a situation to develop in which a whole generation of Australian children could grow up without ever having seen coal or knowing what it was. It is sad that most children and most Australians have still never seen coal, and think of it as something dirty and uninteresting. The desperate situation of the black coal industry inspired moves by people in industry and in governments, whose plans and efforts have been recorded elsewhere, to modernize coal mining methods, to introduce coal preparation, and generally to restore the mines and the mining communities and to re-cast the steel industry and electricity generation. Amelioration of the traditionally troubled industrial relations was an integral part of this overall programme, and whilst one would wish this aspect had progressed further the situation has, in fact, improved immensely. New investment in exploration, mining, preparation, transport and utilization both by the existing coal mining groups and by new entrants, Australian and overseas, have played a large part in bringing about the transformation of the industry to such a point that Australian needs are being fully met and a large export market is being supplied - a situation that few would have dared to hope for in those dark post-war days. Forecasts of exports from New South Wales and Queensland show coal becoming a dominant foreign exchange earner for an indefinite term. Old King Cole may have vanished from our children's nursery rhymes but King Coal is here to stay, providingthat costs in the industry can be kept within competitive limits. It is all too easy for an industry to price itself out of the export market by inflation, by increased costs for a variety of reasons, and through currency readjustments. A second proviso is that we must continue to encourage a balanced attitude to environmental matters.

Jan 1, 1975

By D François-Bongarçon

After a review of the progresses made on the liberation factor theory since its inception by Gy (1982), a new and surprising result of great practical importance is presented: the liberation factor. First introduced simply as a number between 0 and 1, then shown to be the ratio of two variances, is now shown to be well approximated by the proportion of liberated mineral.CITATION:François-Bongarçon, D, 2017. Evolution of the concept of the liberation factor and a surprising new result, in Proceedings Eighth World Conference on Sampling and Blending , pp 307–310 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By S Hapugoda, H Han, L Lu

Sinter quality depends heavily on the mineral phases, textures and physical structure of the sinter, which are formed upon solidification of the sinter melt. The interaction of sinter initial melt with its surrounding materials will impact the properties of the sinter melt and consequently the solidified structure and quality of resultant sinter. Spreading and penetration are two important phenomena dictating the interaction of the initial melt with its surrounding materials, such as nuclei and adhering fines. In the present study, the penetration behaviour of an initial melt into various natural iron ore substrates of different ore types during sintering was studied using a laboratory scale penetration testing procedure. The penetration depth and width were found to increase with temperature and vary with the type of iron ore due to their unique pore structure and mineralogical texture.

Nov 8, 2021

By S Lockie, G Ivanova, J Rolfe

One of the consequences of mining expansion in the Bowen Basin region of Central Queensland in Australia has been a substantial increase in demand for housing, with subsequent impacts on housing and rental markets. Those pressures are reduced to some extent by a proportion of the workforce choosing to live in other centres and commuting to workplace for block periods. The main factors influencing location choice are: housing availability and affordability, basic urban services and lifestyle of the town and the town physical attractiveness such as coastal town. Low costs housing provided by the mining company acts as an attracting factor for some miners to live in the mining town. Recommendations for three short-term and two long-term strategic policy guidelines to address housing situation and location issues are provided.

Jan 1, 2009

Problems encountered in the design, construction, acceptance, commissioning and early operation of the electrolytic zinc plant at Port Pirie are reviewed. Recommendations based on the author's experience are made for proper control of each phase of the development of new plants.

Jan 1, 1971

By J Jackson, K Nguyen, A Nguyen, E Manlapig

"With the recent advancement in drill core imaging systems, a large volume of high resolution drill core images can now be rapidly collected and mineralogically classified. This paper introduces a novel semi-automated method for rapid prediction of process engineering parameters from this type of image. The aim is to allow for a rapid and low-cost assessment of the ore processing variability within a mineral deposit with a reduced amount of metallurgical test work. This method will see its application primarily in the project evaluation phase, where proper evaluation of the processing variability of the orebody normally requires a prolonged and costly metallurgical test work program. Applying this image-based texture analysis method on the mineralogical classified drill core images, the ores are classified according to their textures. For each engineering parameter, a small number of physical test work is required to produce a data set for training and testing of the predictive model. The paper also presents a case study in which this method has been applied to predict the A*b parameter used in mineral process plant design.CITATION:Nguyen, A, Jackson, J, Nguyen. K and Manlapig, E, 2016. A New Semi-automated Method to Rapidly Evaluate the Processing Variability of the Orebody, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 145–152 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By K Katov, S T. Ciutina, J D. Pyke

The development and optimisation of mill discharge trommels, and specifically their screen panels, can be a neglected area in the complex operation of a minerals processing plant. Trommels are often seen as a ‘set and forget’ component of the circuit, even when significant improvements in design are possible. A redesigned trommel and panel arrangement has simplified and added flexibility to the plant shutdown schedule at Kirkland Lake Gold’s Fosterville Gold Mine in Central Victoria.Prior to the trommel redesign, the shutdown frequency was determined by the expected life of trommel panels at 14 weeks. Planning downtime around this item led to higher maintenance costs and wastage in other areas of the plant. This was particularly disruptive with respect to mill lining change-outs, which were forced out of sequence and often changed prematurely. Fosterville Gold engaged Metso Australia Limited to propose a new trommel design that would better suit the site. The new trommel was engineered to balance simplicity with performance, and incorporated the latest in Modular trommel design, modelling and Finite Elemental Analysis (FEA). Modular Panels and Spiral Segments achieve significantly longer life, and allow in-situ panel change outs, flexibility in spiral and dam positioning and an improvement in classification performance. Trommel panel life has significantly increased from 14 to 71 weeks in the trommel’s highest wearing zone. The new design has eliminated some risks to safety by reducing manual labour and lifting requirements during shutdowns. There is greater flexibility with respect to shutdown requirements. The site is no longer at the mercy of trommel panel lifespan, which allows for better optimisation of wear components in the circuit. CITATION:Pyke, J D, Katov, K and Ciutina, S T, 2018. Modular SAG mill discharge trommel for maintenance flexibility and performance, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 613–620 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By R McIlwraith, B Breul

"This paper discusses the successful use of bituminous geomembranes (BGMs) in mining applications since their development in 1974. It explains and illustrates the structure of a BGM composite, which is a geomembrane manufactured by impregnating a polyester geotextile with a compound of bitumen, elastomer and filler. Examples of applications of BGMs in the mining industry are also presented in the following contexts.Storage of solid waste: storage of mining waste at mines in Canada heap leach pads in France, Peru, Chile and Turkey at the base of a mining waste landfill in Brazil capping of solid mining waste in Chile and Canada temporary capping of mining stockpiles in Australia (with possible reuse of the BGM for other works).Examples of the application of BGMs for the storage of liquid waste in mining containment reservoirs in Canada, Guatemala and Peru will also be given.For each example given, reasons are supplied that supported the choice of BGMs by the clients and consultants, drawn from the following advantages of the BGM:BGMs have excellent puncture strength, due to the internal polyester reinforcement, as well as excellent ultraviolet resistance. This often eliminates the need for a cushion geotextile or cover soil over the BGM.BGMs have a very long life expectancy, in excess of 300 years, in subsoil conditions (Breul et al, 2004).BGMs can be installed in very harsh climatic conditions. They are suitable for high wind environments as their heavy mass per square metre makes them resistant to wind uplift. The low coefficient of thermal expansion means that BGMs are suitable for installation in mines where very low or very high temperatures are expected. This reduces construction delays and allows for a quicker use of the mining facility.The fact that the BGM can be installed by the mine’s own workforce, after appropriate training from the BGM manufacturer, allows for a more flexible construction sequence on the mine.Ability of the BGM to connect to other materials such as concrete, steel, rock and other geomembranes that may be on the mine site.The technical advantages of a BGM enabled the engineering consultants to prepare solutions for their mining clients that had a lower environmental risk, had a faster completion schedule and were overall a cheaper option than with a polymeric geomembrane.CITATION:Breul, B and McIlwraith, R, 2015. Bituminous geomembranes in mine construction, in Proceedings Tailings and Mine Waste Management for the 21st Century, pp 289–296 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 27, 2015

By J Loeb, J Dampney, P Cameron

Optimisation of Blast Design and Execution must be done right the first time. It is too late after the ore is broken. Consequences of poor design and execution negatively affect productivity from load and haul through the primary crusher to processing and hence reduce mine site profits. Harnessing and utilising ‘big data’ from geology, geometallurgy, drill hole location, powder loading, blast timing, blast movement and fragmentation to close the loop in blast design and optimise the blast increases productivity across the entire value chain from Mine to Mill. As the internet of things and artificial intelligence increases the quantity of data available, being able to capture and utilise this data to advantage is a challenge. Recent advances in software and hardware together with the increased power of cloud computing allows engineers to close the blasting loop to increase mine site productivity. Numerous case studies over the years detail significant gains from implementing the innovative technologies available to Mine to Mill projects. The opportunity is available for all members of the multi-discipline teams at each mine site to actively ensure productivity improvements are realised and maintained not only in their area, or silo of responsibility but across the entire mine site. This paper refers to recent case studies which outline how significant improvements in productivity are available to all mining operations to increase mine site profitability and dividends to shareholders.

Jun 22, 2022

By King CJ

The C.S.A. concentrator of Cobar Mines Proprietary Limited was expanded in 1974 to treat 80 000 tonnes of copper-lead-zinc ore per four week period. Jaw crusher product is fed to two par- allel primary autogenous mills followed by a secondary ball mill. Each mill operates in closed circuit with cyclones. Improved control of grinding rate and product sizing has been obtained from this circuit compared with the system of two parallel single stage autogenous mills. The main operational variables are des- Cribed.

Jan 1, 1978

By Morrison J

Considerable confusion is to be found in the methods of estimating mineral reserves. The solution appears to be more cooperation between industry and government to agree upon a classification system with guidelines to overcome the problem of the many variable factors affecting reserves. The classification system proposed by the United States Bureau of Mines and the United States Geological Survey (USBM/USGS) together with the guidelines similar to those suggested by the Australasian Institute of Mining and Metallurgy/Australian Mining Industry Council (AusIMM/AMIC) is recommended for reporting mineral reserves to government.

Jan 1, 1979

By M Yahyaei, P Knights, M S. Kizil, J Qu

Digital Twins (DTs) are transforming business operations across many industries through their accurate representations of physical entities enabled by IoT technologies.

Sep 1, 2024

The basic issues of education for the mineral industry which emerge from experience and from a study of relevant literature are presented with the object of promoting. discussion. The subject is considered primarily from the university point of view and relates more to the disciplines of mining and mineral processing than to geology or perhaps metall- urgy, but the conclusions have wider implic- ations. Continuing education, being the subject of a separate paper, is only briefly discussed. The important and particularly relevant training and industry role of the technician engineer and technician are not considered.

Jan 1, 1974

As this paper is being written primarily for perusal by milling workers, metallurgists and engineers, an attempt will be made to avoid the use of accounting technicalities. Its scope will be confined to a description of the methods employed in the collection of basic information for use in timekeeping, costing, and the compilation of statistics.TIMEKEEPINGEvery applicant for work is asked to furnish the following information, which is collected on a card (size 6 in. x 4 in.)...

Jan 1, 1922

The effect of conditioning energy input on the metallurgical results of an emulsion flotation process has been attributed by previous authors to a detergency process. This publication shows that such a process does not explain the data and that an attrition mechanism is more appropriate.

Jan 1, 1969

Selective continuous surface mining is a rapidly developing system of mining which will have a significant impact on many present and future open cut mines. In many aspects the technology is in its infancy, whilst in other facets concepts drawn from other sectors of engineering are well proven. Full development of the potential and benefits of this technology will only be achieved if the mining companies and manufacturing companies work together to produce machines which the end user really wants.

Jan 1, 1986