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By Liu Z. C

Evans' theory for chisel shaped picks is well known in the field of rock cutting technology. It has been widely accepted as a good mathematical description of how coal and other rocks break under the action of a simple wedge or chisel. Subsequently, Evans proposed a corresponding theory for pointed shaped picks. Theory along with experimental evidence from the laboratory has consistently shown that chisel picks are more efficient than pointed picks. However despite such evidence, pointed picks continue to be the preferred shape in most practical cutting applications. Evans' theory for pointed picks was developed in an attempt to shed light on this apparent incongruity. The theory although predicting forces of the right order was found to be deficient in several respects. This paper examines Evans' theory for pointed picks and proposes changes to it, which brings the theory much more into line with measured data. The issue of the relative efficiencies of chisel and pointed shaped picks is also examined on a theoretical basis and the apparent incongruity is Resolved.

Jan 1, 1995

Throughout industry in Australia, time lost through work accidents and illness is three times greater than strikes. In 1978 in New South Wales alone, 400 workers died, 125,000 were injured, 6,000 were indust- rially deafened, and 3,800 people died of occupational cancer. It has been estimated that less than 10% of workers injured make claims for common law damages. The figure is probably in fact much lower than that. However, common law damages claims are starting to become a boom industry and employers are only now starting to see the effect of the increase in Claims. I predict that within 5 years the number of common law damages claims made will increase dramatically.

Jan 1, 1982

By C Vejrazka

Northparkes is located 27 km north of the township of Parkes in central New South Wales, Australia. The operations consist of underground block cave mines and an ore processing plant that produces high-grade copper and gold concentrate. Production is currently sourced from the E48 Lift 1 block cave mine and open cut stockpiles. Mining commenced at Northparkes in 1994 as an open cut operation. Underground block cave mining began in 1997. Northparkes was the first mine in Australia to use the highly efficient block cave mining method, which relies on gravity and natural rock stresses to fragment the ore.The occurrence of air blasts is one of the principal mining hazards in block caving operations between the time of first undercutting and breakthrough of the cave to surface. As such, it needs to be managed continuously, and risk assessments need to be reviewed on a regular basis for applicability to changing conditions. Unfortunately, there is little literature on how to practically approach air blast risk assessments in a way that can be incorporated in the day-to-day operation of a mine. Previous methods of assessing air blast risk were tedious and results were often unrepeatable.With the extension of the E48 Lift 1 extraction level, it was necessary to assess the air blast risk for the extension drives and develop operational guidelines for production from the extension. A review of the methodology for assessing air blast risks revealed substantial improvement opportunities.This paper outlines the principles used for air blast risk assessments at Northparkes Mines and the methodology employed to achieve efficient, repeatable and auditable results.CITATION:Vejrazka, C, 2016. Northparkes Mines’ current air blast risk assessment practices for block caving operations, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 257–264 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By J E. Everett, K Jupp, T J. Howard

Simulation modelling is a practice commonly used in the mining industry to evaluate alternative process designs. Such modelling is typically undertaken as an optimisation study to increase the efficiencies, productivity and product quality of operating mines. In this situation, real short-term grade variability data of extracted ore are available from production records as input data into the simulation.There is also a need for simulation modelling to be performed before mines are approved for construction to clarify the grade variability characteristics that can be expected from the operating mine and assist in the optimisation of the process design. In this situation no historical short-term grade variability data are available. To achieve meaningful and reliable results from a simulation it is necessary to have input data for the ore to be extracted from the pits, representative of the short-term grade variability that would be expected for the operating mine.This paper describes an example of a path taken to generate realistic input data.A method described as composite cut-off criterion was used to distinguish ore from waste, which gave substantially greater recovered tonnage at target grade compared to the conventional quadrant cut-off grade criteria.The only data available for the project was resource model data in the form of kriged block models, which are known to underestimate true ore grade variability. To achieve realistic results from the simulation it was essential to increase this variability while maintaining the accurate average grades. Areas of certain deposits that were modelled using both kriging and conditional simulation estimation techniques were quantitatively compared to establish the comparative variance and the kriged data was modified to match the conditionally simulated variance.A realistic mining model was generated via a process of discretisation and regularisation of the resource blocks. Quantitative assessment demonstrated that this method adequately compensated for ore dilution and that adjustment for ore loss was not required due to an ore skin surrounding the edge blocks.The conditioned data was then used to generate a schedule of daily mine extraction, considering grade variability, tonnage, equipment constraints and extensive blended-in-blended-out precrusher stockpiles to feed into the process design simulations.For the precrusher stockpiles a number of alternative allocation criteria were examined for ore being extracted from the pits to identify the best method in achieving reduced variability through the daily scheduling system. The study concluded that a single analyte separation criterion produced acceptable variability with minimal complexity.The blending efficiency of manually stacked and reclaimed precrusher stockpiles was studied to determine a realistic blending efficiency within the pile. A recommended method of building and reclaiming was determined to give maximum blending efficiency.Finally, the data was used as input into process design simulation models; simulation from crusher feed to shiploading demonstrating that control of shipment grade variability was achievable and that the conditioning of the data delivered realistic results.CITATION:Jupp, K, Howard, T J and Everett, J E, 2013. Generating synthetic data for simulation modelling in iron ore, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013 , pp 231-238 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 29, 2013

By S Liu, N M. Rana, A Take, N Ghahramani, D Clohan, S McDougall, S G. Evans, H J. Chen

Tailings dam breaches have caused significant life loss, social, economic and environmental damage in recent years. The term "tailings-flow" refers to various forms of tailings outflow movement resulting from the breach of a tailings dam. These flows, comprising a mixture of tailings, water and dam materials, can take different forms, ranging from a debris flood to a flowslide, and can travel long distances and impact large areas. The inundation extents depend on the failure mechanism, tailings dam height, total released volume, sediment concentration (associated with the rheological behaviour of the flow) and downstream conditions (including topography, land cover and presence of a water body). Numerical runout modelling of tailings dam breaches is important for predicting the dynamics and extent of tailings-flows, which are crucial steps in tailings dam consequence analysis and risk management. This paper presents a comparison of numerical simulations of the 1994 Merriespruit tailings dam breach using three numerical models: DAN3D, FLO-2D and MADflow3D. Using compiled site condition information and data from the literature and public domain, model performance was evaluated primarily based on comparisons between the observed and simulated inundation extents. The main purpose of this preliminary model benchmarking exercise was to help us evaluate the capabilities and limitations of each model, and to identify opportunities for future model improvements as part of a broader research initiative known as CanBreach. This exercise also highlights the inherent complexity of tailings-flows and the importance of using judgement to interpret model input and results.

Jul 1, 2021

By McNabb K. E

Significant coal reserves in New South Wales lie under areas with steep topography such as valley slopes and cliffs. Subsidence predictions are difficult to make for these locations as existing empirical databases cannot cover all permutations of topography and mining geometry. Two dimensional numerical model alternatives are of limited applicability. Consequently a novel three-dimensional numerical model is developed including the detailed panel layout, realistic rock mass properties including the full stratigraphy, goaf behaviour and actual surface topography. Model results show the same trends as subsidence measurements from Baal Bone Colliery in the Western Coalfield of New South Wales.

Jan 1, 1992

Mining projects frequently fail to meet their financial objectives. A significant area of poor performance lies in the areas of resource estimation, reserve definitions, selective mining and metal accounting. The processes leading to the exploi

Jan 1, 1998

Productivity of mines can be improved by taking fewer, but larger blasts. The initial blasts taken in starting a mining block are restricted by the low amount of void or space to fire into. Block cave mines are using a blasting technique to blast areas that have less than the normally accepted minimum void to establish drawbells for their orebody development. This technique used in block caving mines can be used to improve productivity in mining operations that utilise other mining methods. Some larger blasts have been done in mines, using open stoping methods, which have had void ratios as low as 13 per cent. This has been possible with the use of the explosive gases to transport the broken rock out of the area normally considered to be available to blasts. This trapping of the explosive gases in the broken rock has allowed rock to be moved over 30 m, horizontally, to allow for more void to be available in the blast area. This gives the necessary void ratio allowable to fire larger blasts. This paper will discuss the blasts where this technique has been used in mines to increase the tonnes fired in low void situations. It will also discuss where this type of blasting may improve the productivity of underground mines. Figure 1 shows the how explosive gases have enabled the broken rock to flow out of a draw point without the typical air blast and fly rock that would normally cause a rope suspended sign to be damaged beyond use.

Jan 1, 2008

By Grant J

In surface mining, significant improvements in efficiency can be obtained through greater control over the formation of the muckpile. By tailoring the muckpile shape and its looseness to the requirements of the excavating equipment savings can be rea- lised through increased production, machine life and reduced maintenance. For instance, one open cut coal mine has recently estimated that a 2001o improvement in its front row throw would realise $320,000/year savings in rehandle costs alone. Previously greater throw has been achieved by increasing the powder factor through increased quantity of explosive or by drill- ing a larger number of holes-both at a significant cost penalty. However a recent series of experimental blasts demonstrated that it was possible to achieve a twofold increase in the distance of throw of a single row blast by simply changing delay timing alone. The Nobel Electronic Delay Detonator was used to provide the timing flexibility and control required for a thorough study of the effect of blast timing on heave. Whilst it is well accepted that the front row of a blast dominates the extent of throw, it was also found that the profile of the blast could be significantly altered. To date, the general consensus has been that the muckpile for- mation from a blast is a function of the blast geometry, the rock type, the explosive and the initiation sequence. Typically the geometry, rock type and initiation system have a far greater impact than the explosive type. This has been demonstrated by many high speed film studies. However the extent of influence via initiation has rarely been fully evaluated, owing largely to the limited control offered by conventional detonators.

Jan 1, 1988

By Osborne V. J, Urbank W

An explosion occurred at Moura No. 4 underground coal mine in Queensland on 16 July 1986 and resulted in the loss of 12 lives. The official report of the accident concluded that the most likely source of ignition was the flame safety lamp. This paper describes an investigation of the behaviour of a flame safety lamp, similar to the one involved in the Moura explosion in atmospheres of methane, coal dust and air, carried out at the Queensland Department of Mines . Testing and Research Station. The behaviour of the lamp is described in conditions of varying methane and coal dust concentrations in air, and varying air velocity. Particular emphasis is given to the 'phenomenon of burning which occurs inside the gauze and which is capable of causing the ignition of an external explosive atmosphere.

Jan 1, 1988

By C R. Sundberg

Despite nearly a half-century of continuous production, the low-grade iron ore (taconite) deposits of North America remain economically competitive sources of raw materials for the domestic steel industry. The continued viability of these mature integrated mining-concentrationagglomeration complexes requires highly efficient utilisation of assets, especially the mineral resource. At Cleveland-CliffsÆ five North American managed operations, enhanced ore characterisation techniques are playing a critical role in their continued success. Due to the low-grade nature and complex mineralogical composition of these deposits, ore characterisation cannot solely rely on assay grades. Historically, taconite ore characterisation has augmented assay grades with bench-scale concentration tests to quantify recoverable mineral. The economic necessity for improvements in mill efficiencies and final product quality has mandated significantly greater knowledge of ore-related impacts. Cliffs Technology Center has met this challenge by developing a variety of novel iron ore characterisation techniques. The applications developed include both in situ and laboratory procedures, plus unconventional data integration methods uniquely suited for these deposits. This paper details the evolution of these novel ore characterisation techniques and their application to each phase of the operation: mining-concentrating-and pelletising. The improved ore characterisation techniques have contributed to successes at individual Cleveland-Cliffs managed operations including mineral recoveries exceeding 95 per cent and productivity increases exceeding ten per cent while consistently achieving customer product quality objectives.

Jan 1, 2002

By Martin JD, McNicol JH

The electrolytic zinc plant at Port Pirie South Australia, was designed and constructed to treat zinc oxide fume recovered by treatment of lead blast furnace slag in two fuming furnaces, The plant was commissioned in late 1967. The equipment installed and the oper- ating procedures adopted,'are described in some detail.

Jan 1, 1975

Before commencing design of a coal prepar ation plant, it is essential to have detailed information of the raw coal to be treated to- gether with a clear understanding of the products required. Prediction of raw coal size distribution, particularly the amount of fine material, is difficult and the methods employed should be large scale pilot plant studies or techniques to simulate coal degradation and shale breakdown in water. A detailed knowledge of well proven coal preparation processes and new developments allows processes and process combinations to be compared to'obtain the maximum economic recovery when using lower cost, less efficient processes within acceptable limits. Equipment should be selected bearing in mind its precise application and the location where it is installed. Plant layout should be carefully studied to minimise equipment requirements and to simplify construction. Measurement, control and automation should be an integral part of plant design in order to obtain the optimum performance of the processing equipment.

Jan 1, 1974

By Woodcock JT

Successful chemical control of flotation requires practical solutions to many problems. A brief discussion is first given of those para- meters which can be controlled and those which it would be desirable to control. Suitable analytical methods for application to flowing pulp and to clear solution from pulp are out- lined in relation to on-line and off-line control. Practical problems of deciding where a measurement is to be made or a sample is to be taken and how the sample is to be prepared and presented to the measuring device are then considered. Equipment calibration and maintenance are considered in relation to the above factors.

Jan 1, 1978

Investigations into the flotation behaviour of single minerals, mineral mixtures and ores at the CSIRO Division of Mineral and Process Engineering have led to the development of sophisticated laboratory flotation testing equipment. Both routine and complicated flotation investigations can be conducted in a precise and reproducible manner using procedures and equipment that have been refined over many years of conducting careful batch flotation testwork. Several important advances in flotation research can be attributed to changes in testing procedure developed as a consequence of the availability of this equipment. The flotation cell and ancillary equipment is described and associated developments and techniques discussed.

Jan 1, 1992

By Hyde L. J

Blasting is one of the available technologies to be employed in underground excavation systems. In many instances it can be the only technology which is suitable. The recent moves towards more mechanised working systems is resulting in a reduced awareness of new blasting practices and technologies on the part of many excavation engineers. Recent developments in blasting systems can be utilised to significantly improve operating efficiency, reduce total cycle times, better comply with regional environmental constraints and reduce the total cost of underground excavation. Blasting is and will remain, a very adaptable and exciting alternative which is far from boring.

Jan 1, 1987

By P Mugebe, M Yahyaei, M S. Kizil, R Low

This paper seeks to establish an empirical relationship between the impact of mining technological innovation implementation and a company’s market value. The company’s market value is represented by its stock price. In a bid to ascertain the relationship, a stock price prediction model is sought to be established using the firm-specific factors impacted by the implementation of innovative technology. This work is performed under the watch of the prevailing macroeconomic factors. The background anchors in the understanding that the difference between the economic status of a mineral deposit and its uneconomic status lies in the level of mining technological innovation most prevalent at a given time (Hartwick, Olewiler and Preuss, 1986; Wellmer and Scholz, 2017; Wright and Czelusta, 2003). This is derived from productivity improvement, resulting in sustainable profitability due to technological innovation. Unfortunately, there is not an adequately established relationship that links this technological innovation impact to the share price performance of the mineral commodity company.

Sep 1, 2024

By S Dunham

A cross-discipline approach combining geology, metallurgy and mine planning, geometallurgy is seen as the next logical advance in improving the design and operation of mining businesses. This rapidly evolving field is focused on realising the value that has often been lost in the chasms between the aforementioned technical silos. When successful, the geometallurgical approach promises the ability to tailor mining and mineral processing development and operational options more closely to the characteristics of the resource with resulting lower costs (both capital and operating), improved recoveries and fewer project failures.As with any technological (or managerial) change, there will be side effects from the success of the geometallurgical approach that will impact areas beyond obvious linkages between geology and processing. Some of these effects have the potential to be beneficial to the resource industry and society in general. Beyond the basic geometallurgical promise of closer alignment between processing design/strategy and the multivariate 3D spatial characteristics of the mineralisation, this paper discusses the broader implications and ramifications of the emergent geometallurgical approach: enhancing exploration and discovery; improving project development success; achieving sustainability in an industry working with non-renewable resources; in a world of increasingly hard won license to operate, improving the management of potentially harmful by-products and waste materials (with knock on effects for proactive management of closure issues); smarter approaches to energy management and thus optimisation of projects with respect to carbon footprint; and potential to re-value assets and thus realise a strategic advantage in the area of acquisitions, divestments, mergers and take overs. The authors strongly believe that companies that actively engage with the above issues (and ensure that technical efforts in the area of geometallurgy are not isolated from the larger value chain activities of the firm) will be able to exploit the opportunities that consequentially arise. These early adopters will gain first mover advantages. Firms taking the broad view of geometallurgy will have an opportunity to maximise stakeholder value and win greater success than their less insightful competitors.

Sep 5, 2011

The paper outlines the philosophies and the methods applied to resource estimation by North Flinders Mines Limited at The Granites. These are based on recognition of the prime importance of quality data, accurate geological perception of the deposit, and the judgement of the estimator. With reference to one particular deposit, East Bullakitchie, the series of resources statements published over a 5 year period is compared with the corresponding history of discovery and development. The comparison Illustrates:

Jan 1, 1990

By Kwok S, Haemmerle A

Treatment methods for a low grade deposit at Mt. Fitch near Rum Jungle, N.T., were investigated. Physical beneficiation of the ore, sulphuric acid leaching, carbonate leaching and various methods of uranium extraction from the leach liquor were studied. Although the deposit occurs in a carbonate environment, acid leaching of the ore after beneficiation by radiometric sorting appears to be the most economic treatment method. Uranium would be recovered from the leach liquor by solvent extraction.

Jan 1, 1970