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By J Knecht, R Klymowsky, E Burchardt

The wide spread introduction of SAG mills into grinding circuits 20 years ago was the last development which had a major impact on the design and economics of comminution circuits. Single SAG mills were able to replace batteries of high maintenance and cost intensive crushers in order to achieve high throughput operations. Today, where the head grades of gold and copper ores are falling, there is again a strong need for a significant breakthrough to reduce investment and operating costs as well as improve metal recoveries. High-pressure grinding rolls is the new technology available to meet this challenge. HPGRÆs are state-of-the-art in several mining and minerals applications such as the grinding of iron ores and concentrates, and diamond bearing ores. Reasons for their success in these industries are overall cost reductions and improved product properties achieved by the application of high compressive forces. But these ores are relatively soft, with unconfined compressive strengths up to 150 Mpa.

Jan 1, 2000

By S Hapugoda, M Peterson, A Haileslassie, A Poliakov, E Donskoi, L Lu

Most metallic iron in the world is produced in blast furnaces from different feed stocks – sinter, lump ore and pellets. Sinter is the main iron-containing feed to the blast furnace and can constitute up to 70–85 per cent of the total ferrous burden. As sinter quality is a key element for stable blast furnace operation, the textural, chemical and physical characteristics of the sinter are very important. Two major factors that affect sinter strength are mineralogy and porosity. This study utilised optical image analysis (OIA) to characterise sinter mineralogy, and the results were compared to those obtained by manual point counting under the optical microscope.Two major mineral characteristics of iron ore sinter are the presence of primary (unreacted) and secondary (derived from melt) hematite. Standard OIA, which is based on RGB thresholding, is not able to distinguish them as they have the same reflectivity; however, primary and secondary hematite in iron ore sinter have a different morphology. The CSIRO-developed OIA software Mineral4/Recognition4 has a unique feature to identify various textures/morphologies of the same mineral. Together with other capabilities of the Mineral4/Recognition4 software, this feature was used to identify different types of hematite and silico-ferrite of calcium and aluminium and other common sinter phases, such as magnetite, larnite, glass and remnant aluminosilicates.A visual comparison of the sinter mineralogy present in optical photomicrographs and that present in the mineral maps created automatically by the Mineral4 module of the CSIRO software confirmed the accuracy of the automated mineral identification.CITATION:Donskoi, E, Hapugoda, S, Lu, L, Poliakov, A, Peterson, M and Haileslassie, A, 2015. Advances in optical image analysis of iron ore sinter, in Proceedings Iron Ore 2015, pp 543–548 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By K Luthbom, A Lagerkvist

According to the Swedish Environmental Protection Agency, the number of potentially contaminated sites in Sweden is approximately 40 000. The funding for remediation from the Swedish Government alone amounts to $A 60 - 80 M (300 - 400 MSEK) annually for the period 2003 - 2006. Uncertainties will arise when obtaining samples in field, preparing them in laboratories and analysing them. Different procedures give rise to varying errors. Using data for decision-making that does not truly represent the site could be fatal. Misclassification of soil could lead to unnecessary costs or to risks to human health and the environment. The total uncertainty of an environmental sample can be split into analytical uncertainty and sampling uncertainty. The analytical uncertainty is usually known and reported from routine analysis. The size of the sampling uncertainty is less well known. Hence, the question is how big are the sampling uncertainties for contaminated soil and how big is the analytical error compared to the total sampling error? A scrap yard and two landfills within a workshop area were investigated. An excavator dug trial pits and samples were taken with a trowel from the walls of the trial pits. Samples were put into plastic bags and taken off site for preparation and analysis using XRF. Sample preparation included drying and sieving. The samples were homogenised by kneading the sample bags prior to analysis. The sampling and sample handling were performed in an intuitively way without knowledge of sampling theory. However, Pierre GyÆs sampling theory was used for subsequent evaluation of the data from the site investigation. The theory defines seven sampling errors, which can be applied to sampling of soil. Some errors have a variance that can be calculated or at least estimated, while other errors can give some idea whether the bias is positive or negative. The total sampling error varied over three orders of magnitudes from sample to sample. The single largest contributor to the large variation in error was the contaminant level. When comparing the analytical error and the total sampling error the ratio varies more than three orders of magnitude.

Jan 1, 2005

By AJ LYNCH

Broken Hill metallurgists have been responsible for some of the most important developments in mineral processing technology. These occurred mainly in two periods, 1902 - 15 and 1955 - 70. Mineral flotation was developed as an industrial process during the first period and this happened in two stages, the recovery of zinc minerals from the tailings dump accumulated during the gravity concentration of the oxidised ores and the selective recovery of galena and marmatite during flotation of the primary ores. During the second period fast accurate analytical procedures were developed to provide rapid assessment of process performance, and new means of controlling the process were devised which improved throughputs, grades and recoveries. These technological successes were due to the skills of the metallurgists and the commitment of the companies. They brought large financial returns. They were achieved under difficult circumstance. There are important lessons to be learnt from these successes.

Jan 1, 1992

By S J. Schafrik, M Long

There are several factors that are increasing the need for new graduates to be ready to design and manage more autonomous operations at mines. Autonomous controls and systems range from the start-up, control, and shutdown of processing plants to the autonomous operation of vehicles. These operations require the workers, engineers, and management to have additional skills for programming, debugging, tasking, and maintaining the equipment. The future survivability of many mining operations will be influenced by a company’s willingness and ability to understand, accept, and utilise this technology for safe and productive operations. This is an educational opportunity and challenge that needs to be addressed throughout the student’s experience, from first year to graduate level. This paper discusses the lessons learned from a decade of multidepartment effort at all student levels and many courses that are able to incorporate data science, controls, and autonomous design into the already topic-rich national curriculum. This approach also exposes other engineering disciplines to the mining industry which is a valuable recruiting tool for talent outside of the mining engineering departments.

Sep 1, 2024

By T C. Souza Pinto, M Safari, F S. Hoseinian, D Deglon, L Leal Filhoc

In this study, the effect of hydrodynamic parameters on the iron ore reverse was investigated in a mechanical flotation cell. The work carries out using the case study of Iron ore from Vale in Brazil. The influence of hydrodynamic factors such as froth height, impeller speed, superficial gas velocity and solids percentage were evaluated on the quartz flotation. The results showed that the hydrodynamic conditions have a great effect on the flotation performance, especially on the fine and coarse quartz. The size-by-size analysis of the froth products showed that froth height, impeller speed, superficial gas velocity and solids percentage have a significant effect on true flotation quartz particles. The increase in the froth height decreased the recovery of quartz particles. The increase in the impeller speed increases the recovery of quartz particles to an optimum. The increase in the superficial gas velocity improved the flotation of coarse quartz particles. The increase in the solids percentage increases the recovery of quartz particles.

Sep 18, 2023

By B BussiFre, J Molson, M Aubertin, G W. Wils

Waste rock piles containing reactive sulfide minerals can serve as long-term sources of acid mine drainage (AMD). Within these piles, many physical, geochemical and biological processes can contribute to the production of AMD. The flow of water, for example, depends on internal pile structure, which depends on the dumping methods used to construct the pile. In this paper, the internal structure and grain size distribution of typical waste rock piles are first reviewed with respect to their effect on internal water flow. A numerical model is then applied to simulate unsaturated flow within a waste pile assuming two primary waste materials, different atmospheric conditions and several geometric configurations. The simulations suggest that water movement can be controlled by introducing fine-grained material layers within the coarser host material. However, these layers should not be horizontal because they can lead to localised high-saturation regions as well as preferential flow favouring the production of AMD. A shallow slope towards the pile boundary may be introduced to force drainage to the outside while maintaining low saturation within the interior, thus reducing the production of AMD.

Jan 1, 2003

By D McB Martin, A Piechocka, M Jessell, M Lindsay, E Ramanaidou

The Hamersley Basin of Western Australia, approximately 500 km long by 200 km wide, is recognised globally for its rich endowment of iron ore resources. Two types of bedded iron ore mineralisation are recognised: the Proterozoic hypogene martite-microplaty hematite ores; and the more recent Cenozoic supergene martite-goethite ores. Exploration strategies depend on the style of mineralisation being targeted; however, stratigraphy and structure are fundamental controls on both ore types. Therefore, the ability to visualise the 3D geology of the entire basin is critical for the understanding of iron ore occurrences and their relationship to ore genesis of bedded iron ore mineralisation. However, due to the large size of the basin, generating a 3D geological model of the regional stratigraphy and structure has not been possible, or prioritised, primarily due to software limitations. Recent advances in implicit automated geological modelling presents an ideal opportunity to develop a 3D model of the entire Hamersley Basin. The innovative Loop software was used to model open source geological data (ie geological mapping, outcrop orientation data, and fault data) sourced from the Geological Survey of Western Australia. In addition to generating a 3D geological model, information such as stratigraphic thickness and fault offset information was extracted using the map2loop module and demonstrated its application to exploration targeting. This study demonstrates how a basin-wide 3D geological model was used to conduct a regional structural analysis of the Hamersley Basin. The results of this study provide opportunities for other prospective regions to be rapidly modelled in order to enhance the understanding of the geology and improve exploration targeting.

Nov 8, 2021

By P J. Hawke

Within the Mesa J pisolitic iron ore mine, clay is distributed unevenly throughout the deposit and often forms as pods and channels less than 10 m in width. The mine resource model, based on 50 m + 50 m spaced drilling, has been unable to accurately delineate the clay for scheduling and mining purposes. Therefore, alternative methods for mapping the clay-contaminated ore were sought. Predictive clay mapping will significantly reduce production costs at Mesa J through improved selective mining practices, more accurate scheduling, reduced wear on mining equipment and minimising the need for maintenance of haul roads and ramps. High lateral resolution electromagnetic (EM) surveying using a Geonics EM31 instrument can quickly and inexpensively delineate the extent and orientation of the clays. Preliminary results indicate that a block model based on the interpretation of the EM data can accurately predict the distribution, volume and tonnage of ore and waste material. While rip-line mapping, infill drilling, ground penetrating radar and gravity can delineate clay with various degrees of success, none were as efficient as EM31.

Jan 1, 2002

By A Murphy, D Lauder, J Miranda

Minera Alumbrera Limited operates the Alumbrera concentrator, treating a nominal 80 000 tpd of porphyry gold/copper ore. It is located in Argentina, 1200 km north-west of Buenos Aires in Catamarca Province, at an elevation of 2550 m above sea level. Treatment facilities consist of crushing, SAG and primary ball mill grinding circuits, rougher flotation, ball mill regrinding, gravity recovery and cleaner flotation. It is one of only a small number of concentrators in the world, which uses Jameson Cells alone for cleaner circuit flotation. Plant design was started in June 1995, with commissioning commencing in July 1997. Following a successful ramping up to design tonnages and recoveries, a number of options were reviewed to improve gold and copper recoveries. This paper concentrates on a detailed size by size flotation recovery project, commenced in May 1999. Utilising optical microscopy, scanning electron microscopy and analysis of surface chemistry it has allowed losses by size fraction to be quantified and options for enhanced recoveries to be developed. Coupled with extensive circuit surveys it has also provided an insight into previously unknown properties of Jameson Cell operation. Among these are unique residence time and bubble formation reactions to reagent and pulp flow variations, which has permitted a number of novel changes to the operation to maximise capacity and recovery.

Jan 1, 2000

By Johnson N. W, Manlapig E. V, Alexander D. J, Franzidis J. P

The importance of the froth region on flotation performance is often emphasised in the literature. It is well-known that decreasing froth depth or increasing air flowrate results in increasing cell recovery at the cost of lower concentrate gra

Jan 1, 1997

The importance of proper planning, preparation, and execution of a steady state sampling campaign for metallurgical plant assessment must not be underestimated. Careful planning can increase the amount and reliability of information from an optimum number of samples and fully utilize available plant data. It requires specification of the data required, determination of run duration sampling frequency, the selection, modification and testing of sample points and cutters, as well as organisation and briefing of plant and sampling personnel. Preparation immediately prior to sampling, the conduct of the sampling campaign itself and procedures to handle the collected samples and information are discussed. Cutter design, fabrication and use are described in detail, and typical sampling situations, for ball mills, classifiers, pipes, launders, flotation cells and thickeners are considered individually. Measurement of pulp flow rate can often resolve difficult mass balance problems, and discussion of convenient techniques is included.

Jan 1, 1976

By E Yurakov, D J. Ashelford, M I. Slate

The push for increasing coal production rates continues to place increasing demands on mine management to safely and effectively control seam gas. Gas drainage strategies applied vary in both effectiveness and form. Methods employed are a function of assessed risk, gas reservoir characteristics, surface and underground access, budgetary constraints and gas utilisation potential. With the aim of establishing and optimising the effectiveness and efficiency of gas drainage systems, Australian coal miners in cooperation with gas management specialists are embracing the use of gas reservoir simulators and gas emission models. This paper discusses the evolution of gas drainage practices in Australian underground coal mines and the role of gas reservoir assessment methods in optimising gas drainage systems and gas production forecasts.

Jan 1, 2005

By G M. Volkmann

Pipe umbrella systems have effectively been used as an additional support system in the working area in weak ground conditions during the last decades. Thus, a considerable number of applications accounts in urban tunnelling with shallow overburden. However, this support system is also successfully used when a tunnel alignment crosses fault zones, sediments, moraines or talus with overburdens from shallow to deep. The pipe umbrella support system itself is termed differently worldwide – synonyms are canopy tube umbrella method, umbrella arch method, or long fore-poling method.One main reason for the increase in application is that this support system closes cost-effectively the gap between reasonable, normal supported tunnels and tunnels supported with more expensive special techniques like horizontal jet-grouting or ground freezing. By using this system, many projects can be built more cost effective without decreasing the common level of safety.The pipe umbrella construction method is pretty young, so the knowledge about this system has been intensely researched in the last decade. This led to an enormous increase in understanding the interaction between support system and surrounding ground, the mode of action, and the important details for construction.Pipe umbrella support systems are applied in difficult ground conditions, so a special developed measurement arrangement was used to observe deformations ahead of the working face during tunnelling. The evaluation of collected data sets identifi ed that cased-drilling systems have clear advantages compared to predrilling systems during the installation process in weak ground conditions. This may become important depending on project requirements, so this difference must be considered in design as well as in the tender document specifications.

Mar 8, 2011

In Situ Bioremediation of a Heavily Polluted Alkaline Soil in a Uranium Deposit

Sep 13, 2010

Aspects and anomalies in the present Standard Specifications for Blended Cements which may have operated in Australia against the development of the greater use of Slag Blended Cements are noted. Estimates of slag and ash usage in Australia are given and the need for further research with local materials stressed.

Jan 1, 1979

By Baafi E. Y

In this paper, impact of expert systems development is examined from the coal mining point of view. Some introductory concepts about expert systems are explained with a view to identifying possible beneficial applications of expert systems in coal Mining.

Jan 1, 1988

Current NSW Government policy requires searching for more than just minerals during an exploration program û add endangered fauna and archaeological relics for a start.

Jan 1, 1995

Open cut low grade gold mines form the basis of the current upsurge in the mining industry in Australia. The effect on profitability in the short term and viability in the long term requires accurate estimation of grade and tonnages. The application of the Ditch Witch Trenching Machine as a grade control tool has occurred rapidly and the machine is now a working tool in many mines throughout Western Australia.

Jan 1, 1987

Successful restoration of Ballarat region alluvial gold workings to Box-Ironbark forest requires realistic evaluation of techniques. A stocking level threshold of 68 percent is used to rate the success of 'broadcast' seeding of E. microcarpa, E. Melliodora and E. Leucoxylon.Failure necessitates follow-up enrichment planting with tubestock, which is considered undesirable, interalia, due to pathogen, spacing and economic problems.

Jan 1, 1992