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By M M. Tarshan

Separator performance is evaluated by the so-called separation efficiency. The concept of efficiency in mineral dressing operations must be interpreted with considerable care. Although qualitative use of term efficiency is valid and useful, difficulties arise in expressing it quantitatively because two conflicting criteria, grade and recovery are normally involved in its evaluation. It is undesirable to express efficiency as a single value, even though this is frequently done in practice, since there are strictly speaking an infinite number of combinations of grade and recovery that can give that one value. Inefficiencies in processes can be attributed to three broad sources: mineral limitations as represented by the separability curves, equipment limitations (which prevent the maximum separation indicated by the separability curves), and human failure to minimise these inefficiencies. In the present paper, the efficiency of a two-constituent separation process has been examined. The separation process has been evaluated by comparing the sharpness factor of the actual, the absolutely efficient and the absolutely inefficient operations.

Jan 1, 2000

By C V. Deutsch

"Geometallurgical variables often cause problems to conventional geostatistical workflows. There are many variables; some are compositional and some are non-additive. They often show: complex multivariate relationships undersampling relative to conventional grade variables unequal sampling; that is, all variables are not available at all data locations.A variety of approaches have been developed over the years, but geostatisticians remain mostly focused on modelling rock types and a few grade variables with an abundance of data. The problems are reviewed and a chained workflow is presented where appropriate techniques are employed in sequence to permit reliable spatial prediction of geometallurgical variables. The spatial models may be used to assess the value of additional data, for prediction of process performance, for improved mine planning and other optimisation tasks. The chained workflow will include data transformations such as ratios and normal scores that make the variables amenable to geostatistical modelling. Data imputation techniques to account for missing values are considered with special consideration to spatial correlation with the available data. Decorrelation techniques such as the principal components, min/max autocorrelation factors and projection pursuit multivariate transformation are employed to manage massively multivariate modelling. Full distribution modelling must be considered to avoid biases in the prediction of non-additive variables. The post-processing of geometallurgical models must be streamlined for robustness and efficiency. The precise workflow varies according to the specific purpose of the study. Guidelines and thoughts on best practice are presented.CITATION:Deutsch, C V, 2013. Geostatistical modelling of geometallurgical variables - problems and solutions, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013, pp 7-16 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 29, 2013

By F Shi, G Ballantyne, K Runge

There has been minimal innovation in the methods used to process an ore over the last 50 years. Productivity increases have largely resulted in increased equipment size without implementation of parallel improvements in technology. Complex orebodies of the future will need mining operations to adopt new technologies and techniques to make future ore treatment economically viable. Three emerging technologies, namely high voltage pulse (HVP) pretreatment, fine screening and the HydroFloat<sub>TM</sub> coarse particle flotation cell will be presented in this paper and the potential benefits that may result if they are adopted in mineral processing circuits will be outlined. The barriers that must be overcome before they can be adopted by industry with confidence will also be discussed. CITATION: Runge, K, Shi, F and Ballantyne, G, 2018. New technologies that will potentially enable processing of complex orebodies, in Proceedings Complex Orebodies Conference 2018, pp 126–129 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By B L. Dickson, J H. Hodgkinson

The self-organising map (SOM) is an exploratory data mining technique that is both non-traditional and underutilised. Methodologies based on SOM tend to be data-driven and unsupervised, which makes them ideal to assist in the integrated analysis and interpretation of complex and disparate æmineral explorationÆ data sets. While traditional statistical multivariate approaches have difficulty with relationships that are non-linear and data distributions that are not normal, SOM-based data mining procedures are useful in these circumstances. In a SOM analysis each sample is treated as a vector in a data space defined by the variables; and measures of vector similarity, such as the dot-product or Euclidean distance, are used to order or segment a data set into naturally occurring populations. These groupings are positioned as nodes, or groups of nodes, on a 2D rectilinear representation of the multi-dimensional ædata spaceÆ, which is the æself organized mapÆ. While it is common not to include a sampleÆs locational information in the actual SOM analysis, such information can be used to display the spatial location of samples coded by their SOM node or cluster. If one finds there are coherent spatial patterns belonging to samples from particular nodes, or groups of nodes, then there is strong evidence that the technique is determining patterns and relationships within the data that have natural significance. Variations of the SOM technique may be used to perform broad categories of operations, including: 1. outlier identification û for samples belonging to various nodes or grouping of nodes; 2. function fitting, prediction, estimation or imputation û for calibrating relationships between variables and determining replacement values for missing, null or censored values; 3. clustering, pattern recognition or noise reduction û for determining the natural patterns within a data set; and 4. classification û for classifying samples into the clusters determined in three. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Silitonga M

Generally, the acceptable parameter for predicting the intensity of ground vibration due to a blast is the amount of explo ive u ed and the distance from the explo ion. A eries of closely controlled tests were carried out and it was observed that the degree of confinement or burden of an explosive charge play an important role in the variation of the transmitted magnitude of the shock wave through the ground.The intensity of the shock wave increases with burial depth or with greater confinement of an explosion until a critical depth is reached.Beyond this critical depth, the magnitude of ground vibration remain constant. This is an important finding, which explains the anomalies between the expected level and the monitored ground vibration in a particular situation.

Jan 1, 1984

By D Pepper

Despite the limited literature regarding the pressure filtration of mine tailings (compared to the large number of papers published each year on paste thickening of tailings) the number of mines dry stacking filtered tailings is approximately equal to the number of mines storing tailings in paste form. Main drivers for filtering tailings are: water recovery, future rehabilitation costs for tailings storage area and permitting requirements. In arid climates, the cost and scarcity of water justify the capital and operating costs associated with pressure filters. Further justification for filtered tailings is the potential for progressive reclamation of the dry stack, which can proceed earlier and faster than the reclamation of a tailings dam.Filtered tailings must be transported to the storage area by trucks or conveyors. For dry stacking, 70 - 80 per cent solids content (by mass) is typically acceptable, however the primary goal is to provide a filter cake that is consolidated and dry enough to prevent bridging and build-up on the materials handling equipment. It has been observed that high average solids contents (~70 per cent) can be achieved while the centre of the filter cakes is still wet and sticky, presenting challenges for the transportation of the solids. Appropriate controls must be in place to ensure consistently easy to handle solids are discharged from the filter.FLSmidth has installed two fine coal tailings dewatering systems in the United States. One of these systems incorporates a Deep Cone Thickener« upstream of the filter press to minimise the amount of water that must be filtered, while the other tailings filter press is fed by a high rate thickener. The operation and performance of these filters is discussed and compared to the lab testing used to size the full-scale equipment.CITATION:Pepper, D, 2012. Operation of filter presses for tailings dewatering, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 241-246 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

Recent well-publicised problems with the start-up of new mining projects have continued to feed the perception that the mining business in general and Ore Reserves in particular are a poor risk. New mines commonly experience difficulties when the true variability of ore characteristics becomes apparent during commissioning. At this critical stage, the impact of lower metal recovery, reduced throughput or increased consumption of reagents and energy can have a catastrophic effect on economic returns, as illustrated by the premature closure of some operations. There appear to be several common reasons contributing to the poor performance of mining projects, of which three are examined here: lack of early risk assessment before feasibility studies are started, inadequate sampling for metallurgical test work and variability of the run-of-mine (ROM) ore. An underlying feature of these issues is the lack of effective interaction between geologists, mining engineers and metallurgists/ process engineers. Geologists need to be more aware of ore processing issues and the range of characteristics that need to be considered as part of the resource estimate. Metallurgists need a greater understanding of the variability of the run of mine ore in terms of all the characteristics that influence the design and operation of the plant. Mining engineers need to determine the short-term variability of the ore in the mine schedule, so that there is confidence that the quality of the run-of-mine ore will be within the design specifications of the plant. A substantial overlap between these disciplines and sharing of areas of responsibility is necessary if these and other technical problems are to be better understood, production estimates are to be improved and commercial risks are to be reduced. Although the JORC Code (1999) provides guidelines for reporting all the issues that are material to an Ore Reserve estimate, some issues are rarely fully addressed in Ore Reserve reports. In particular there is no formal requirement for a metallurgist to assure his or herself of the appropriateness of the Ore Reserve classification. Consequently the level of uncertainty related to recovered grade and ore processing characteristics may be understated. It is suggested that to meet the concerns of bodies funding new mineral developments a stronger multi-disciplinary approach to the analysis of mineral deposits and reporting of Ore Reserves is required. The culmination of this approach would be the formal requirement for a geologist, mining engineer and a metallurgist to co-sign Ore Reserve reports.

Jan 1, 2002

By Ushakov S

New geological and geophysical in vestigation including our detailed field observation in different regions of the Koryak upland testify that Nor- theastern Eurasia margin eastward of the Ochotsk-Chukotka belt is composed of a collage of allochtonous terranes arcs and sedimentary filling of back- arc basins, which bordered North East Siberia and Chukotka (1)1). Ancient island are assemblages are the most tipical for this region (2-4; shown by heavy line). They are marked by long (500-1000 km) volcanic belts which become younger towards the Pacific up the Latest Jurassic-Neocomi- an (2) to Late Cretaceous (3) and Pale- Gene (4).

Jan 1, 1987

The recent trend of installing flotation cells with volumes as large as 200 m3 in concentrators is driven mainly by economic considerations such as lower capital, operating and maintenance costs. Despite the economic advantages, the metallurgical benefits from these large cells have not yet been fully realised by the industry. This is mainly due to the lack of understanding of cell operation, viz cell mixing and hydrodynamics, gas dispersion and froth transportation behaviour in large cells. There is still no rational basis for selecting optimum cell operating conditions and down-the-bank operating profiles. The relationship between cell operating conditions and metallurgy is not well established. This has resulted in poor utilisation of cell capacity in many operations. The present trend of installation of fewer cells in a bank requires each cell to be operated very efficiently. Optimisation of cell operation provides an opportunity for significant metallurgical improvements in a flotation circuit with minimal capital expenditure. Extensive work on optimising of cell performance has been carried out at various Teck Cominco operations in Canada, Peru and USA. Three different levels were involved in this work. The first level was aimed at identification of cell operating conditions for optimum mixing and hydrodynamics, gas dispersion, entrainment and froth flow behaviour in individual cells. The objective of the second level was to identify the optimum bank operating profile for cells down the bank in a circuit. The third level then focused on controlling these cell operating conditions and bank operating profiles for tighter control of concentrate grade and recovery for optimum bank metallurgy. This paper presents some of the major findings at all three levels and demonstrates the importance of each level in optimising the performance of flotation banks installed with large cells.

Jan 1, 2005

Mathematical economic models for assess ment of technological progress in the mining industry in the USSR are discussed. The models are based on a simple index, TT which approxi- mates the rate of growth of the people's living standards. However, for application in the mining industry it is necessary to incorporate various parameters to account for the dynamic charges in the geological, mining and other technological conditions. Derivations of the models are shown and examples of results are Included.

Jan 1, 1977

To the south and west of Broken Hill lies the Thackaringa silver-lead district, about 25 miles, and is the locality really of the first silver find in the country long before Broken Hill, the geological fomations of which it much resembles. The Iocks and their structure are identical, except that in this area they are  more irregularly foliated and apparently much more faulted and expose in places quick successions of complete anticlines and synclines, even in a single lease. Saddles of ore respectively are found coinciding with the flexures of the rock but many minor veins otherwise and branches exist and make connections which render the whole a mining problem. It follows then that the surface.of the ground after some denudation in dotted with croppings of all the series, and in such a confusing way that the actual strike of a vein may be even confounded with the dip and readily mistaken for it at a few places. The main character of the outcrops are those usual in the district consisting almost wholly of argentiferous and silicious ironstone, sometimes gossan, which at a depth in a few feet changes to a gangue of very silicious carbonate of iron (crystallised), which occurrence is uniform through this district.The exploration of the lodes has not been extensive as it has not been well understood. Shallow shafts and drives have comprised nearly all the mining at present, which is evident on first sight by the numerous shafts and small excavations dotted 'about, as in an alluvial field. The depth of exploration underground in one place had gone several hundreds of feet, never more than 150 feet vertical from the surface in depth and irregular. The undulations of the most continuous work in this direction is such that it presents at different places successively either a tunnel, shaft, underlay winze, level, or Tise, and is on ore all the time, and where the rocks are faulted (which occurs as much as 30 feet and more) these changes are very abrupt, but for working on are suitably connected by the management.

The history of black coal as a fuel dates back in Europe more than 2,300 years, and possibly longer in China. Originally the mining of coal was done by underprivileged people, but with the industrial revolution and the dawn of mechanisation, the status of the coal miner improved. The improvement continued to the present day. Coal miners now take an important role in industrialised countries and enjoy a high standard of living. The miner is amongst the highest paid and best technologically served in any industrial activity. The abundance of coal relative to alternative fuels and its widespread occurrence, brings with it a prosperity much valued in those countries with significant resources such as Australia. Coal will play a major role in easing the world energy shortage. In addition to the conventional usage, throughout the world coal gasification plants are in various stages of development. Coal liquefaction plants are beyond the drawing board stage. Slurry pipelines to supply coal for direct burning in electric generating and other plants are planned. In the current atmosphere of environment consciousness, Australia has to contend with people with only marginal interest trying to influence coal mining activities to the detriment of the overall prosperity of Australia. Fortunately enlightened legislation is the greatest protector of the environment and in many instances great improvement to the environment ensues after mining has passed. With its vast resources of black coal Australia can look forward to a significant role in future supply of fuel. As a result of the trade and industry involved, Australia can become an even more influential country in world politics, trade, and the setting of high living standards.

Jan 1, 1975

By D La Rosa, G Power, K Riihioja

In underground mining, the often unpredictable variability in ground conditions may lead to the application of suboptimal drilling and blasting patterns, resulting in poor performance. Experience and pertinent information to develop and implement improved drilling and blasting strategies can be easily lost due to the lack of means to help engineers store, access and manage this information. The Julius Kruttschnitt Mineral Research Centre (JKMRC) through a series of industry funded applied research projects has been developing a system that can facilitate the drill and blast design, analysis, auditing, documentation and data management processes. The system is a hybrid between an information management software module called BMS (Blast Management System) and two design and analysis modules, 2DRing for underground production blasting activities and 2DFace for development blasting activities. A concise description of the software tools and its applications are given in this paper, supported by two case studies. Opportunities to further develop the software are also highlighted, they include options to integrate these tools to existing drilling and blasting automation systems and portable computing technology to facilitate the design, implementation and continuous improvement processes.

Jan 1, 2001

My purpose here today is to introduce an element of democracy into this seminar. In my experience, the mines of Australia can be divided into two categories; those that pay and those that don't. As far as I can ascertain, every other paper being delivered at this seminar concerns mines which come into the first category, or at any rate are close enough to it for the promoters to be able to afford an expert's valuation.

Jan 1, 1989

Traditional methods for monitoring, and hence controlling, pyrometallurgical processes rely heavily upon the skill and experience of operators. A skilled operator will usually achieve consistent, though often conservative, results, whilst an un-skilled operator will require considerable time and training to achieve the same results. Semtech Metallurgy AB have demonstrated that continuous and precise control of pyrometallurgical processes can be achieved through on-line analysis of pyrometallurgical flame off-gas using optical spectroscopy. The feasibility of the technology has been demonstrated on a large number of full-scale tests at production plants and by several commercial installations. Evidence suggests that installation of this technology, called Semtech Optical Production Control (OPC), has resulted in considerable economic benefits to the plant efficiency and asset life. These economic benefits are believed to be a direct result of improved objective on-line control. Technically the following benefits have been demonstrated: improved metal grade control, reduced metal losses, reduced processing time, and improved personnel safety. SemtechÆs OPC is a non-intrusive technology which relies on the fact that the composition of the vapour phase above a high temperature melt is closely related to the instantaneous status of the melt. This enables on-line real-time analysis of the furnace melt to accurately determine melt status and in particular reaction endpoints. Originally developed for on-line monitoring of copper converting in a Pierce-Smith vessel the field of applications for the technology is steadily growing. This paper introduces the Semtech OPC technology; discusses various applications and outlines the demonstrated benefits.

Jan 1, 2002

The complete life cycle of a production facility has many phases requiring many different skills and many different personalities. It is not unlike the life cycle of a person and many parallels can be drawn from it. I leave some of these analogous situations to your fertile minds. The author, having worked in operations, plant design, plant commissioning, marketing and many other interesting situations through the industry has drawn from this experience and examples given by many associates in the industry.The phases seen are as follows: Concept Studies û someone has a bright idea of how to make a dollar. Scope Studies û what possible processes/options that could make a dollar. Prefeasibility Study û the æviableÆ scope options are studied to develop feasible options. Feasibility study û defines the concepts that should be designed to make a viable project thus enabling financing and project commitment to be made. Detailed Design û an intermediate step that consolidates the inputs to give a robust plant that can be constructed.Construction û people can see what they thought was going to occur and start to understand the plant. Commissioning û the hand-over of æownershipÆ from the conceiverÆs to the operators. Operations û the ætoyÆ has become reality and money must be made. De-commissioning û the plant has seen out the useful life of the ore deposit, it now goes through a further process required by society.Across these phases of plant design run several countervailing management requirements that can influence the outcome of the plant design. Some of the management rigours that have to be applied to the various phases are as follows: costing basis of the various phases; operational and maintenance reviews; sustainable development; risk assessment; reliability reviews; equipment availability; commissioning time; and environmental review.This paper endeavours to awaken people to the phases that projects require for a successful outcome and the management rigour that has to be applied throughout the phases to ensure the correct intellectual horsepower is applied at the right time to ensure the best outcome.Many of you would be parents and realise this is not unlike the development of children, teenagers, adults, retirees and ongoing.

Jan 1, 2002

By Lunarzewski L, Truong D

Although there are sound principles used in the world recognised methods of gas emission prediction, results based on these methods applied to several Australian longwall extractions have yielded unacceptably high discrepancies. With the development of mining in new seams and at higher rates of extraction, the need has grown for a methodical approach to predicting gas emission levels specifically for local Australian mining conditions. Such an approach is developed from results of recorded emission readings during longwall mining at Appin and Pacific Collieries over the past 6 years.

Jan 1, 1988

By Buizen M, Eagleton A. C

The results of calibration trials conducted on parachute stoppings both overseas and in Australia under a recently completed NERD&DC grant, are presented. Applications of parachute stoppings, for rapid regulation and control of ventilation networks are described including use in blasting areas and rescue work. Several parachute-type stoppings are described and their applications Investigated

Jan 1, 1988

By Schommarz KH, Dunne RC, Goodall CM

Column cells are widely used today for the recovery of base metals by flotation. Their use for the flotation of iron sulphides has not been as rapid. Australia has pioneered the use of large rougher flotation columns. During the last six years, seven rougher columns have been installed on gold mines treating iron sulphides and the technical viability of this technology has been demonstrated. Laboratory column testwork on a gold bearing iron sulphide ore demonstrated the effects of both physical and chemical parameters. In general the large commercial columns operate over a broad range of conditions depending on the downstream treatment of the flotation concentrate. The addition of wash water to commercial columns is not universally applied and there appears to be a need for a better wash water System.

Jan 1, 1993

By J E. Everett

Ore selection is generally a highly subjective task, with emphasis on producing product with a consistent target grade matching a perceived market requirement. A composite selection criterion ‘Comp’ (a linear function of the grade vector) can be used to maximise ore tonnage at a specified target grade (in Fe and contaminants) extractable from a block model. The blocks correspond to the selective mining units, with grades interpolated from diamond drill hole data. An iterative procedure has been developed to identify the coefficients and cut-off value for the composite function ‘Comp’, maximising potential ore tonnage at target grade.Commonly, target grade is predetermined by marketing; however, there is no guarantee that maximising ore tonnage at a specified target grade maximises the potential value of the mine. If the value of ore could be expressed as a linear function of the grade components, then these coefficients would be appropriate for the selection criterion ‘Comp’. The cut-off value for ‘Comp’ would correspond to the marginal cost of production; all blocks with a ‘Comp’ score above the cut-off would be classified as ore; and the cumulative grade of these ore blocks would be the average product grade over the life of the mine.Unfortunately, no such value function for iron ore is generally available. Methods for estimating the value function are discussed, using the spot price and sensitivities based either upon operational tolerances for Fe and the contaminants or upon published price differentials. This approach has been applied to an anonymous Pilbara deposit with about one million blocks averaging 1.1 kt. It is shown how the optimal target grade, cut-off grade and maximum tonnage can all be explored as a function of marginal cost and iron ore price. Alternatively, given marginal cost and an iron ore price, the effects of changing the tolerances (and therefore the relative costs of the contaminants) can also be explored.It is suggested this procedure can enable informed decision-making for an iron ore mine. Rather than setting final policy for the entire life-of-mine, the method enables target grades and tonnage estimates to be revised by re-computation as the mine life proceeds to recognise changes in market conditions and knowledge about the resource.It should be emphasised that this paper is concerned with ore selection rather than ore sequencing. Appropriate ore selection is a necessary but not sufficient condition for maximising value. Having identified the set of blocks that potentially maximise value, the sequence in which they are mined will present a trade-off between producing at constant grade and extracting high value ore early. The sequencing issue is not considered here. It is shown that optimum ore selection for an open pit mine is independent of any consideration of discount rates, although ore sequencing will depend upon the time value of money if the product grade is to vary across time.CITATION:Everett, J E, 2015. Ore selection to maximise value, in Proceedings Iron Ore 2015, pp 443–448 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015