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By S Mitra, B J. Monaghan, T Honeyands, G Evans, R Chowdhury, D Scimone

Due to the harsh operating conditions, wearing of the inner refractory lining in a Basic Oxygen Steelmaking (BOS) furnace reduces the useful life of the refractories and incurs a significant cost component for relining. In this study, firstly, a combined compressible and incompressible computational fluid dynamics (CFD) model was developed to identify the potential wear prone zones in an industrial scale BOS system during the supersonic oxygen blowing phase by quantifying the wall shear stress distributions. Next, the retained slag splashing process was simulated by introducing an inert gas to residual slag mass to achieve a protective coating on the refractory walls. Effect of both design and operational parameters such as lance head configuration, lance position and the initial slag volume on the slag wall coating performance were quantified and most favourable conditions were determined.

Jun 19, 2024

By J O. Okonkwo

AngloGold operates various gold mines in South Africa, the largest of which are situated in the North West province. The impact of AngloGold Vaal River mining operations on the environment and, specifically, on aquifers and groundwater is assessed. The location of such aquifers and plumes is determined by remote-sensing and ground-sensing operations, followed up with the correct placement of monitoring boreholes from which information such as water rest levels, chemistry and geological data is gathered. This study utilises an integrated approach consisting of the following mutually reinforcing phases: Phase 1: Airborne multi spectral scanning; Phase 2: Airborne thermal remote sensing; Phase 3: Ground resistivity survey; Phase 4: Borehole placement; and Phase 5: Sampling and monitoring. The integration of the investigation tools and phases in use at AngloGold Vaal River has been found to be very useful in determining the exact sources of contamination, the direction of flow of such contamination, the positioning of interceptive measures and the analysis of such contamination. This adopted approach will enable the development of flow transport models that will further enhance our knowledge of contaminants in aquifers at the mine and enable management to conduct educated interventions.

Jan 1, 2003

It is hypothesised that increasing the number of loading passes will produce a reduced range of truck payload outcomes compared with four-pass loading. The paper provides analysis to support this hypothesis. It is shown that, hypothetically, loading trucks with five or more passes will result in reduced tendency for overloading and reduced confidence interval for truck payloads that increase the confidence level of containing high end payloads within safe and commercially acceptable limits. Furthermore, increased number of passes provides for more precise bucket load spotting and so improves distribution of payloads within truck bodies. Truck-loading issues examined by the paper include: Improvement in life of driveline components and tyres. Generally tyre costs are relatively moderate; but tyres tend to become an increasingly sensitive performance/cost component as truck scale increases; Reduction of site severity fects flowing on to suspensions, truck frames and structural components generally with potential for reduced long-term repair costs; Less physical body damage due to smaller load increments; Reduced risk of non-compliance with payload limitations for safe braking standards; Increase in loading cycle times tend to increase with scale of loading machinery within the limits of a specific type of equipment (ie rope shovels or hydraulic shovels). Production increase with increased bucket capacity is, to a degree, offset by slower loading cycle times. This is particularly pronounced with front-end loaders but tends to be less noticeable with hydraulic excavators/shovels and electric rope shovels. Decrease in loading time, as a proportion of total truck-cycle time as open pits deepen and dump reaches increase. The production and cost benefits of four-pass loading tend to diminish as truck cycle times increase. The paper also discusses the implications for loading-equipment philosophy to satisfy the future needs of the industry. Cost benefits from upscaling tend to diminish as truck scale increases, so increasing management diligence and close monitoring are required to ensure that expected outcomes are realised. These truck-loading issues have been researched to assess the benefits positive or negative) of four-pass loading in practical scenarios. An attempt is made to determine whether four-pass loading is a æmust-haveÆ or merely a æmythÆ.

Jan 1, 2003

By L Rachmad

Freeport IndonesiaÆs Deep Ore Zone (DOZ) mine is the new underground block caving mine within the East Ertsberg Skarn System (EESS) deposit which started production in mid-2000. The DOZ will produce 25 000 tpd using mechanised block cave mining method and will be the fourth underground mine opened within the EESS deposit. Evaluations were made on former block caving mines at PT Freeport Indonesia (IOZ, GBT Area I and II) in order to design a more appropriate support system. As a permanent support, the thread bar bolt support system is widely used in the DOZ mine. The advantages of this system are ease of operation, quality control and high bond strength. The main problem of this system is the curing time of about 28 days to achieve maximum strength, necessitating the installation of a temporary support for its implementation. In this instance, the system was inefficient in operation and studies were required to find an alternative grouting system. This paper examines the evaluation of thread bar bolt support system and compares the performance of two types of grouting (resin cartridge and cement cartridge) with cement grouting performance. The evaluation is conducted with a pull out test. The advantages and disadvantages for each grouting method, comparison of cost estimation and grouting application in mine scale are presented in this paper.

Jan 1, 2002

Early in 1950 a new laboratory was set up to deal with problems in mineragraphy, petrology and metallography. This paper describes the equipment, the organisation and association of the laboratory with the various departments of the company, the work that has been done and future plans.At Mount Isa it was soon realised that the microscope would play a most important role in mineral dressing problems and aiding geological research.As early as 1928, R. J. Colony submitted a petrographic report on Black Star ore for Consolidated Limited; much later, in 1934-5 Dr. Grondijs published for Mount Isa Mines Limited a preliminary study of the Mount Isa orebody, followed by a mineragraphicinvestigation of mill products, and in 1937 a Study of Mount Isa Ores by H. GrondIjs and C. Schouten appeared in Economic Geology, for June-July. Other papers dealing with the petrology and mineragraphy of Mount Isa ores are appended at the end of the paper.The mill research metallurgical staff has endeavoured to incorporate mineragraphy in solving milling problems and determining the effectiveness of laboratory as well as examining minerals sent in by the geological department.For many years the amount of equipment available was limited and much of it was locally made or improvised. An improvised briquetting machine, and grinding and polishing lap gave moderate results in conjunction with an old, but serviceable, Leitz microscope. However, for more detailed and accurate work not possible with improvised equipment, many mineragraphic problems were sent to specialist in.

Jan 1, 1953

By Boyd G. L

Stress measurement is at the core of most stability design analyses. It is demonstrated that contrary to accepted practice, it is the field measurement, and not the calculated prediction, of stress that requires most examination and review. Since it is not really possible to quantify rockmass properties, the stiffness values used in reduction of stress measurements and in subsequent design analyses (either empirical or numerical modelling) must consider an appropriate range of values.

Jan 1, 1995

Coal geology plays an essential role in the investigation of in situ coal seam quality. Coal geology can also play an important part in laboratory studies such as coal washing and coking, and in operating plant problems.

Jan 1, 1976

By Nickelsen J, Theisen KG, Hansen PH

The use of stationary calciners in the processing of aluminium hydroxide has emphas- ized the importance of Bayer hydrate properties with respect to particle breakdown during calcination and subsequent treatment. Test results from calcination of several Bayer hydrates to sandy alumina in the FLS Gas Suspension Calciner (GSC) were obtained in a 250 kg/h pilot plant unit. Particle breakdown during calcination was influenced by content of solid sodium oxalate, trapped in the hydrate particles and operating gas velocities. Owing to the design and operational principles of the GSC it is possible to reduce particle breakdown to at least the same as what is found in long rotary kilns. Other major advantages reviewed are obtained through simplifications in plant design and operation, pointing to low specific power and heat consumption, and generally low production costs, thereby providing an attractive alternative to fluid-bed calciners.

Jan 1, 1981

By Morland R

In the course of an exploration program aimed at increasing Pasminco Mining's ore reserves, an electromagnetic survey down one of the underground drillholes at the North Mine, Broken Hill, recorded a broad and persistent response. This paper demonstrates that the anomaly was not due to any geological feature, but rather was caused by 'self-response' of the sensing probe. The observed results are due to the surveyed hole lying within a resistive environment and having distinct, but not unusual, changes in dip.This phenomenon has not been widely reported and we believe that there are likely to be similar cases in company records where very genuine looking responses are due to self-response rather than sulphides. These false anomalies can be recognised by correlating the observed data with the calculated down-hole component of the transmitting loop's primary field.

Jan 1, 1994

By O Bøckman, E Thisted, K H. Esbensen, U Thisted

Process industry measurement systems, once installed, are often interpreted as static black boxes delivering correct values as long as not proven otherwise. After first implementation and set-up with a distinct sampling frequency, they often run ‘forever’ without checking if this frequency is still appropriate with respect to changed raw materials characteristics, different process conditions or changed customer specifications. Failure detection is based on operator experience and skills (often close to an art form) and/or from control measurements of reference samples. This may well be too late for many industrial process contexts. An appropriate sampling frequency is a critical success factor for valid monitoring and control.Based on the methodology of variographic analysis we here illustrate how to design/re-design/optimise an industrial measurement system in terms of sampling frequency, discretisation and accuracy based on customer specifications. We also show how variographics can be used to monitor for deviations. We use experience from process industry to show how these methods can be used not only for product characterisation, but also for monitoring input factors, process indicators and measurement of these. The information hidden in the vast amounts of data that is continuously created in modern process industries can be utilised to cut costs in the measurement activities and at the same time contribute to early error detection. We illustrate by case examples from production processes at a nickel refinery, supporting the Lean and Six Sigma methodology. This will provide a standard operating procedure for monitoring the stability of measurement systems, and provide a basis with which to discuss how a variographic approach can be integrated with the Lean and Six Sigma approach as an online tool to map, characterise and validate measurement systems and thus avoid more cumbersome measurement system analysis in full detail.CITATION:Thisted, E, Thisted, U, Bøckman, O and Esbensen, K H, 2017. Variographic case study for designing, monitoring and optimising industrial measurement systems – the missing link in Lean and Six Sigma, in Proceedings Eighth World Conference on Sampling and Blending , pp 359–366 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By J Harmse

This paper deals with the modernisation of the brakes on an electrically coupled Blair multi-rope hoist and covers the removal of the old calliper brakes and hydraulic control system, and its replacement with brake discs, disc braking units and hydraulic control systems. The paper covers the braking requirements of the hoist, which is made up of two electrically coupled single-drum hoists, together with the theory behind the choice of brakes and control systems supplied. The paper also covers the project logistics that were required in order to install and commission the new brakes and control systems with the minimum disruption to production on the only rock hoist on a major production shaft. Items covered include the modifications to civil works, pre-installation of bearing lubrication systems, brake discs and hydraulics and the interfacing of the new hydraulic control system to the existing electric control system. It had to be designed to be compatible to a new electric drive and control system due for installation at the end of 2005.

Jan 1, 2005

By Howes PM

In the iron and steelmaking processes, dusts are generated and treated by wet dedust- ing methods to form slurries which are high in iron content, but also contain certain impuri- ties. For many years these slurries have been processed and the wet cake, which is produced, has been dumped because of the high zinc and alkali chloride contents. Sintering is an appropriate process for recycling of these materials, provided the deleterious impurities can be kept under control. Zinc is a deleterious element in blast furnaces because it promotes the formation of accretions on the upper walls of the furnace. This results in irregular furnace performance. Alkali chlorides effect the emissions from the sinter plant waste gas due to the high resis- tivity of these components, resulting in decreased efficiency of the electrostatic precipitator. Experimental work indicated a concentra- tion of zinc in the -11 pmt particle size frac- tion. A cyclone plant was installed producing a "coarse" usable product and a "fine" waste Product.

Jan 1, 1984

By K Nilsson, G Cheong

Troy Resources NL acquired a 70 per cent interest in the Mina Sertpo gold project in Goißs State, Brazil, in 2001 following a successful bid for the highly competitive international tender of a tenement package put out by Western Mining Corporation (WMC). The Sertpo deposit is located on cleared grazing land 380 km west of Brasilia and is 30 per cent owned by Amazonia Mineracao Ltda, a private Brazilian company. It is a small high grade open-pittable orebody with a measured and indicated resource of 108 000 tonnes at a grade of 49.7 g/t for 172 500 ounces using a 2.0 g/t cut-off. Troy undertook the project management and development of the project while Amazonia managed the exploration activities and provided other services as required. The project development involved drilling metallurgical test holes, scouring the world to locate an available and suitable second-hand plant, and arranging shipping to andreconstruction in Brazil.

Jan 1, 2004

By Beeby C. j, Fernando W. J, Ming M. Q I, Guang Li Xi

Removal of moisture in steam-fluidized, mainly steam-heated, fluidized beds makes possible significant energy savings over conventional forms of large-scale drying. The systens are described and their applications to brown coal and alumina hydrate are reviewed. In application to brown coal the use of the system to permit meeting diurnal variation in power station output, and the use of triple-effect drying to minimise coal usage and to avoid the necessity of recovering in the turbines the energy in the steam from the last dryer are discussed. To facilitate the rapid adoption of the systems proposed, studies are being made of heat-transfer to dried coal, of moisture equilibrium in pressurized and vacuum systems, of tapered beds as a means of reducing carrier steam and permitting wider size variation, and of the use of carrier solids for drying lump materials.

Jan 1, 1989

By M B. Lovitt

At present there exist few engineering calculations and principles to determine exclusion zones for personnel in the vicinity of underground explosive storage areas. This paper is written to encourage discussion and proposes a method to determine the impact of a blast wave through scientific principles. Then, criteria to determine an ‘exclusion zone’ need to be identified.There has been much work on identifying the pressure rise and the energy of explosive detonations underground but little to develop standards in criteria that can be used to identify exclusion zones for useful design of underground infrastructure. The author presents the newest ways of calculating the pressure rise and energy (impulse) of detonations and puts forward some criteria to be used in the identification of personnel exclusion zones to spark peer review and discussion of these criteria towards developing standards for engineering design.Smith and Sapko (2005) used Sach’s scaling laws to develop a relationship for both pressure rise and impulse, which incorporated factors for intersections. Intersections will have a large bearing on the peak pressure and the energy of the blast wave and needs to be incorporated. Silvestrini, Genova and Leon Trujillo (2009) developed the scaling laws with an energy concentration factor to predict blast propagation in partially confined geometries and together the author has proposed equations for determining the peak side pressure and the impulse in a tunnel. Given the weight and type of the explosive, the average cross-section of the tunnel complex and the number and type of intersections encountered, the pressure and impulse can be calculated.The military has carried out many investigations as to the influence of blast pressure and impulse on the human body. Lung damage, ear damage and velocity knock down are three of the criteria standards that are presented as possible methods of determining exclusion zones around an underground explosives magazine. The author suggests that the velocity curves presented by Bowen, Fletcher and Richmond (1968) could be an acceptable method of determining an exclusion zone as it incorporates the side pressure and the energy of a blast wave to determine the ability of the wave to knock down personnel.CITATION:Lovitt, M B, 2014. Exclusion zone calculation for underground explosives storage, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 319–326 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By Enever JR

In-situ rock stress measurements conducted in the Phillipines and on Bougainville have revealed stress fields significantly different from expectations based on intraplate experience. The results have potential significance in regard to both engineering practice in the Pacific Rim region as well as in helping to understand the geological processes occuring near subduction Zones.

Jan 1, 1987

By Dobos SK

The Black Ridge Gold Deposit is located in the northern part of the Clermont Goldfield, which is situated at the boundary of the Bowen Basin and Anakie Inlier, Queensland. The goldfield comprises a series of NNW-trending semi-isolated basins, which are tectonically aligned with the Denison Trough, the west-most division of the Bowen Basin (Fig. 1-1).The main stratigraphic units in the deposits in younging sequence are the Anakie Metamorphics, the early Permian Blair Athol Coal Measures, the late Permian(?) White Section, and the Tertiary basalts which are regionally widespread, and intruded by abundant mafic and felsic plugs.

Jan 1, 1990

By G Collecutt, D Proud, D Humphreys

"The hazards associated with dust explosions are well known, and coal dust explosions present a significant hazard in the underground coal mining industry worldwide. In earlier work, we presented computational fluid dynamics (CFD) simulations and test results for coal dust explosions within a 2.5 m diameter circular gallery, along with CFD simulations and test results for the suppression of these explosions with finely atomised water sprays. In this paper, we present refinements to the CFD modelling that yield a significantly improved calibration with the test results, and proceed to investigate by CFD the requirements for suppression of a coal dust explosion in a typical underground roadway. This work was carried out under an ACARP project and we gratefully acknowledge their assistance. CITATION: Proud, D, Collecutt, G and Humphreys, D, 2015. Computational fluid dynamics modelling of coal dust explosions and suppression systems, in Proceedings The Australian Mine Ventilation Conference, pp 309–314 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Aug 31, 2015

By A K. Bayer

When the human eye fails in the evaluation of quality parameters in the extraction of minerals the use of laser-induced fluorescence analysis (LIF) can supply more detailed information on the composition of rocks. On the basis of measurements of selected raw materials engineering concepts for the use of this method in the mining industry as an innovative system for horizon control of mining machines will be described and the most important analysis parameters, influencing factors and interference variables are presented.

Jan 1, 2003

By D Luppnow, H Rourke

Recent disasters such as the failure of the Mount Polley tailings embankment remind us of the risks that tailings facilities pose. It is widely recognised that dam-break assessments are a vital tool in identifying the consequences of the failure of a facility, which in turn can be used to develop emergency action plans. A typical assessment includes an estimation of breach parameters and outflow volume, followed by the preparation of an inundation map to illustrate potential flow extents and downstream impacts. This paper focuses on the estimation of outflow volumes, which is an area that the authors feel can be improved. Presently, many types of analyses assume that the volume of tailings released is only a function of the storage volume and dam height. After a review of several documented tailings failures, it has been found that the extent and depth of the supernatant pond needs to be considered as it is just as important, if not more so, as the storage volume and dam height. Tailings facilities with excess water storage have a higher risk of failure as they are more susceptible to overtopping, piping and liquefaction failures. In addition, they pose greater failure consequences as the saturated conditions will lead to more material being mobilised.This paper has reviewed available information on a number of tailings dam failures and proposes an alternative estimation of potential tailings release volumes as a function of supernatant water stored on the facility for use in dam-break analyses. In a broader sense, the paper seeks to shift the current risk paradigm from tailings dam heights to volumes of water stored and provides a basis for continuing research and discussion.CITATION:Rourke, H and Luppnow, D, 2015. The risks of excess water on tailings facilities and its application to dam-break studies, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 225–230 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015