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By C J. Greet

Oil can enter a flotation circuit from a number of sources (for example, from mining equipment, oil leaks from the grinding equipment and coatings on the grinding media, but to name a few). Folklore generally states that any oil that contaminates the ore entering the flotation circuit is considered to have a negative impact on flotation. That is, a loss in concentrate grade and recovery.This represents a dilemma for some grinding media suppliers, who use a variety of quenching medium (air, polymer, oil or water) to achieve the desired physical properties of the ball. In the case of high chrome grinding media it is necessary, in some instances, to quench in oil to give the ball the right degree of toughness, which invariably leads to these balls having a thin film of oil on their surface. Once the grinding media arrives on site and site personnel recognise that the balls are “covered” in oil, they generally insist that the oil will have a deleterious impact on flotation performance.Obviously, any supplier “worth their salt” would take remedial action at the point of manufacture to minimise this problem. However, does quenching oil actually present a significant “threat” to the flotation process? This paper provides both laboratory and plant data describing the effect quenching oil has on the flotation of copper sulphide ore, with surprising results!

Aug 8, 2011

Autogenous and Semi-Autogenous grinding has become an accepted method of reducing primary crusher product to micron sizes in a single or a two-stage grinding circuit. The elimination of secondary and tertiary crusher circuits and sometimes rod mills helps to lower overall operating costs and, in many instances, can make uneconomical projects viable. Selecting AG/SAG Mills have been rather a "hit and miss" affair over the years, but now with the many different types of tests available, accurate mill size predictions can be made, provided the test data is evaluated correctly. This paper endeavours to simplify the process of evaluating test data and sets down some guidelines for designers to follow when selecting AG/SAG Mills.

Jan 1, 1991

By M Olsson, U Nyberg, K Widenberg, P Svedensten, F Ouchterlony

During 2007 and 2008, the project Optimal Fragmentation in Blasting II was conducted at the Långåsen quarry of NCC Roads AB near Arlanda. The main goals were:an evaluation of the effect of using electronic delay detonators (EDDs) in quarry blastinga validation of the design curve concept introduced at the Vändle quarry.Five production blasts were monitored. After a first trial round, the remaining four rounds each had about 100 Ø89 mm holes in a 14–19 m high bench charged with site mixed emulsions. In rounds 1 and 2, a tighter pattern than normal was used in one half of the rounds, raising the specific charge there from 0.7 to 1.0 kg/m3. Non-electric initiation was used with two holes per 25 ms delay in-row and 67 ms between rows. In rounds 3 and 4, electronic delay detonators were used instead, with 10 and 5 ms in-row delays respectively.The monitoring encompassed drill hole collaring and alignment, in-hole deviations, the rock structure in the bench faces from 3D imaging, first row burdens, etc. Eleven 400 t samples were taken from the muck piles and sorted in the quarry and sieved in the laboratory (lab). The lab data made up a fines tail that was grafted onto the in-pit sorting data to form sieving curves for the test piles. These curves were then compensated for the absence of boulders to construct the sieving curves for the blasted muck pile.These have been used to derive fragmentation model formulas for the non-electric rounds, also called design formulas. They are based on blast geometry, charging data and the properties of the rock mass. The formulas may be used to estimate the effect of changing blasthole pattern, borehole diameter and stemming length for example.The use of EDDs gave several unexpected results. In comparison with non-electric initiated rounds with a somewhat lower specific charge the fragmentation was much coarser; x50 increased from 160 to 200 mm. The effect of raising the specific charge in the non-electric initiated rounds from 0.72 to 0.99 kg/m3 was a much finer fragmentation; x50 decreased from 160 to 120 mm.CITATION:Ouchterlony, F, Nyberg, U, Olsson, M, Widenberg, K and Svedensten, P, 2015. Effects of specific charge and electronic delay detonators on fragmentation in an aggregate quarry – building fragmentation model design curves, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 727–740 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By D Kavanagh, C Michaud

"A continuous improvement initiative was identified at Kalgoorlie Consolidated Gold Mine’s (KCGM) Fimiston open pit with the goal of reducing bench turnover time and increasing shovel digability by improving fragmentation around previously mined-out stopes. In the past, a higher number of blasts than normal would be required to get through a single excavation area where stopes were present. This is due to the limited reach capability of the drilling fleet from safe ground into restricted areas requiring the drilling of the shot to be done in a staged manner. In addition, the holes that were able to be drilled in the area did not remain open long enough to be loaded with explosives as a result of the poor ground conditions surrounding the stopes.Over the last 18 months, KCGM has trialled drill additives to improve blasthole stability, as well as introducing a remote drill rig allowing holes to be drilled in areas previously inaccessible by manned drill rigs. This has resulted in improved penetration rates in bad ground conditions, improved drill hole stability, better shovel digability, and an overall reduction in bench turnover of at least ten days on the benchmarked 126 days average per bench. KCGM is now in the final stages of the improvement project with the installation of a drill monitoring system on the fleet to allow live data transfer back to the office for analysis, as well as providing improved accuracy on drill holes in restricted areas.Citation:Michaud, C and Kavanagh, D, 2016. Reducing Bench Turnover Time and Improving Shovel Digability, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 19–27 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By R Ayothiraman

Tunnel excavation may induce adverse effects on nearby existing structures/foundations in urban areas. Accurate prediction of tunnelling effects on pile foundations of nearby structures in the urban environment poses a major challenge during design. Several studies have been undertaken to understand the mechanisms of the soil-tunnel-pile interaction, which focused only on influence of tunnelling on nearby existing building and foundations. However, effect of pile loading on existing tunnels did not receive enough research attention so far. So it is essential to measure the response of existing tunnel-lining due to loading on newly constructed pile to assess to the safety against the additional forces/moment caused by pile loading and to evaluate the critical distance for the proposed construction of any structures from the tunnel location. This paper presents result of three-dimensional (3D) finite element analysis carried out in ABAQUS to investigate the effects of pile loading on existing tunnels embedded in cohesive soil. It is found that the effects on tunnel lining depend on horizontal separation distance between pile and tunnel as well as location/elevation of pile tip with respect to tunnel location.

Mar 8, 2011

By J-T Zhu, Q-Y Tu, S-L Kong, L Wang, Y-P Cheng, H-Y Liu, Q-L Yang

China is the largest coal-producing country in the world, while the geological conditions of deep coal mining are extremely complicated with high ground stress, high gas pressure and low permeability, which results in the difficulty of gas drainage and aggravation of gas explosion and coal and gas outburst disasters. Co-extraction of coal and gas is an effective method to eliminate coalmine gas disasters and realise the safe exploitation of coal and efficient gas drainage at the same time. This concept is widely accepted by the main coal-producing countries around the world, while the concrete definition of co-extraction is vague and not unified, and there is little accurate theoretical support for co-extraction of coal and gas, which makes it hard to determine efficient gas drainage methods correspondingly according to the features of coal seams in a comprehensive and systematic way. Based on theoretical analysis, laboratory test and field observations, basic thoughts and specific definition of co-extraction of coal and gas were put forward after analysing the occurrence characteristics of coal seams in China. We obtained the mechanism of mining-enhanced permeability and established the corresponding theoretical model, which is the process of fracture network formation through opening recovery of the original fractures and new fractures produced by unloading damage. Based on the core idea of ‘mining-enhanced permeability’, engineering approaches of ‘unloading by boreholes drilling’ for the single coal seam and ‘unloading by protective seam mining’ for the coal seam group were proposed to realise safe and efficient co-extraction of coal and gas. Meanwhile, combined with engineering practice, we put forward the construction principle of coal exploitation and gas drainage system in different coal seam occurrence conditions. The above methods were applied successfully in the Tunlan coalmine in Shanxi Province and the Panyi coalmine in Anhui Province, which had established the ‘underground-surface united’ spatial gas drainage modes, and could ensure safe and efficient co-extraction of coal and gas in the outburst coalmines.CITATION:Cheng, Y-P, Wang, L, Liu, H-Y, Kong, S-L, Yang, Q-L, Zhu, J-T and Tu, Q-Y, 2015. Theory of safe and efficient co-extraction of coal and gas and its applications, in Proceedings The Australian Mine Ventilation Conference, pp 79–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By M Spleit

A long-term production schedule for the LabMag iron ore deposit in northern Quebec, Canada is derived using stochastic integer programming. The optimisation formulation maximises the schedule’s net present value while simultaneously managing the risk of deviations in production tonnages and qualities by considering stochastic simulations of the orebody instead of a single deterministic model. The formulation also smooths and minimises haul truck requirements and ensures that as mining progresses, space is created within the mined out pit for the return of waste material.CITATION:Spleit, M, 2014. Production schedule optimisation – meeting targets by hedging against geological risk while addressing environmental and equipment concerns, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 397–404 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By R Salmimies

Choosing a ceramic capillary action filter is often favoured in processes where low energy consumption is important, such as the dewatering of iron ore. In addition, the performance of the filter medium is essential, and the possibility to regenerate the medium is an advantage compared to other types of filter media. Although low, roughly 8 - 9 w-per cent for iron ore concentrate, and even cake moisture is the primary goal of dewatering, the introduction of better filtration processes can result in significant improvements of water economy and material efficiency.As industrial beneficiation processes are often complicated in their chemistry due to impurities originating from the ore itself, from the up-stream processing equipment and from the process water used, the characterisation of the filter media after usage might provide relevant information on what actually takes place during long operating periods. The aim of this study was to obtain new information on the fouling of fi lter media in an iron ore process to enhance and develop the regeneration process of the media in the future.X-ray diffraction and scanning electron microscopy were used to characterise ceramic filter media used in the dewatering of magnetite. Principal component analysis and discriminant analysis were introduced to identify trends in the data. Two types of media blockages were found to play an important role in an acidic iron ore dewatering process: fouling by slurry particles and by in situ crystallisation of a calcium compound, of which the latter originated from the combination of process water and process chemistry.

Jul 11, 2011

By A Kyllo a, D R. Swinbourne

Electric arc furnace (EAF) dusts contain significant quantities of zinc, found almost entirely as either zinc oxide or zinc ferrite. The dust has been classified as a hazardous waste due to the relative high lead, cadmium and hexavalent chromium contents. It is important that environmentally acceptable processes be developed to treat this waste. One possible process involves reacting the zinc compounds in the dust with metallic iron, thus avoiding zinc vapour reoxidation by CO2 as occurs in carbon reduction processes. It consists of two stages where the first is the reduction of iron oxides to iron and the second the reduction of zinc oxide to zinc vapour by the iron. In this work the effects of operating variables such as temperature, CO/CO2 ratio and pressure on the recovery of zinc from an industrial EAF dust obtained from the Smorgon Steel Mill were investigated. Zinc recoveries in the second stage were found to approach 100 per cent at 1000oC after about four hours in nitrogen but within 40 minutes if a low vacuum was used.

Jan 1, 2000

By L Gobbo

X-ray diffraction (XRD) provides useful information about the composition of an ore sample in terms of quantification of crystalline phases and amorphous content. The use of new, fast detection systems implemented in CubiX FAST industrial diffractometers creates the opportunity to use this technique in exploration and modern process control. Besides the chemical composition of iron ores, their phase composition is also an important factor for exploration, quality control and processing. In the analysis of iron ore, XRD can identify the phases containing iron, such as haematite Fe2O3, magnetite Fe3O4, and goethite FeO(OH), and any other mineral phases present, especially silicas. Quantitative analysis is possible by various classical methods such as straight line or polynomial calibration with standards, but modern quantification analysis techniques such as Rietveld analysis or full pattern autoscale analysis are attractive alternatives, as they do not require any standards. These methods offer impressive accuracy and speed of analysis. Another analysis technique offering great benefit to ore exploration and process control is cluster analysis. This technique greatly simplifies the analysis of a large amount of data, eg from drill core samplings, and automatically sorts closely related scans of an experiment into separate clusters and marks the most representative scan of each cluster as well as outlying patterns. This can facilitate multi-dimensional compositional mapping of ore deposits, identifying regions of favourable mineral composition and allows fast and reliable tracking of the process. It is the most economic procedure to have automatic data evaluation without involving any dedicated personnel in the process. Details of the techniques used, sample optimisation methodologies, results, data precision and limitations will be discussed. The approaches have enormous potential as an inexpensive, reliable tool, useful in the characterisation of iron ore materials in an industrial environment.

Jan 1, 2009

By Y Wei, H-B Mnhlhaus

Particles are by far the easiest objects to simulate, because their dynamics is simple. Determining the motion of particles and their interaction, a wide variety of deformable structures can be constructed by connecting particles that have mass, position, and velocity, and that respond to forces. Starting from this simple idea we have derived what we call the particle-lattice method for the solutions of boundary value problems of deformation and fracture of solid mass. The problem of rock breaking by blasting operations as well as fracture and flow of rocks fragments involve momentum transfer between solid and fluid; gas flow and reactive mass transfer. In this paper we outline the method and describe briefly the salient features of the algorithm. We derive relationships between the contact properties for the discrete model and the properties of the underlying continuum and fluid flow coupling procedure. Finally we illustrate the potential of the method by means of example solutions related to the dynamic fracture and flow in jointed rock by blasting.

Jan 1, 1999

The title of this paper suggests rather a comprehensive survey of the industry, but since it is not possible to do justice to this in a short paper, and, as the bulk of the Australian trade consists of buttwelded tube, the author proposes to deal only with this type.The buttweld process has been praetised for many years and, as the methods of manufacture are not widely known, a brief history of its development may be of interest. Few good reference books in the English language are available, and this reticence may possibly have retarded advancement in manufacture.The earliest method of making ferrous tubes consisted of bending a thin plate or strip to form a "skelp." The "skelp" was then raised to a welding heat and hammerwelded on an internal mandrel on a smith's anvil. Necessity, however, soon produced mechanical methods of making tubes, and, in 1812, an Englishman named Osborn patented machinery for "welding and making barrels of fire-arms and other cylindrical articles." The apparatus was arranged as shown in Fig. 1.The skelp was raised to a welding heat and placed in the swage block "A." A mandrel was then inserted and the tube lapwelded by the action of the tilt hammer.Various modifications of this apparatus quickly followed, to keep pace with the rapidly growing demand and the exigencies of war. These tubes were essentially of short length and mainly used for gun barrels. The advent of coal gas for lighting (patented by Murdoch) created a demand for small tubes of longer length, and necessity, as usual, produced a solution. In 1824 Jas. Russell, from *Works Manager, Stewarts & Lloyds (Australia) Pty. Ltd.

Jan 1, 1935

By S Maritsa, E K. Chiwandika, S M. Masuka

The iron and steel industry is experiencing an increase in the use of iron and steel commodities within societies, decarbonisation pressures, depletion of high iron ore grades and high energy consumption. This necessitates scrap metal recycling, low-grade ore utilisation using the induction or electric arc furnace to achieve the global target of net zero CO2 emission. The available highquality scrap metal cannot sustain the steel industry but the world has unused hematite-goethite ores. It is the aim of this research that this resource be utilised using the induction furnace to sustain the steel industry in an environmentally friendly manner. Indurated pellets prepared from the hematite-goethite ore, 5 wt per cent limestone and 5 wt per cent coal addition were smelted in the induction furnace at 1350 ± 50°C with 25 mins holding time. The effects of basicity and carbon content were also investigated to optimise the smelting parameters. The results showed that the careful control of the basicity, and iron-to-carbon ratio maximised total metal recovery. The optimal basicity ratio was determined to be 1.3 and a carbon to iron ratio of 1.4 achieved a total metal recovery of 73 per cent. The metal recovery was closely related to the estimated slag melting temperature. The basicity ratio of 1.3 achieved the lowest slag melting temperature estimated to be around 1380°C based on the CaO-SiO2-Al2O3 phase diagram. The recovered metal had a comparable chemical composition and microstructure to that products from an ITmk3 furnace.

Jun 19, 2024

The Newmont Waihi Operations mill has undergone significant growth over its life. Initially designed as a single SAG mill operation, the circuit has been progressively upgraded since 1988 from a nameplate capacity of 600 000 tonnes per annum to the current rate of 1.3 million tonnes per annum. With future mining potential there is renewed interest to increase the processing rate even further. Over the next twelve months five sustaining capital projects will be undertaken and two major eco-efficiency projects will be completed. With the exception of the large grinding mills, most equipment on a gold treatment plant is replaced after 10-15 years. Waihi Gold mine has been operating for 14 years and has just recently received approval to replace equipment in five main areas; carbon elution, carbon regeneration, scats crushing, intertank screens and variable speed drives. Each project has been justified on improved process efficiencies and operating/maintenance cost savings. The two eco-efficiency projects involve a water balance model and a cyanide optimisation project, both of which are Corporate key performance indicators (KPI).

Jan 1, 2002

By T Hill, J Everingham, P Clark

Currently, social impact assessment (SIA) is used to determine social impacts across the life-of-mine (LOM) to closure. This paper draws on recently completed SIA reports from the Martha gold mine in Waihi and qualitative interviews in the community that explored post-closure options, to review the challenges mining companies face when engaging with iwi4 through the SIA process and what that may mean for closure planning. The Maori of New Zealand consistently lobby to have a distinct voice in resource management issues. This is in line with the evolution of indigenous participation in SIA globally and with New Zealand policies, not least of which, the Treaty of Waitangi (the founding document of New Zealand) makes provision for Maori self-determination with regard to natural resources. Land use for mining has been a source of conflict for Maori and mining can have profound cultural and social impacts on the Maori community, yet despite Treaty intentions their representation in SIA has been comparatively limited. With this in mind, the Waitangi Tribunal has released the Ko Aotearoa Tenei (Wai 262) report, which recommends far reaching reforms to laws and policies affecting Maori culture and identity including natural resource management. This landmark report seeks to move the Maori-Government relationship beyond grievance to partnership. Given suggested policy changes in Wai 262 and the risks of poorly conceived closure planning, it is timely to review where Maori currently fit into the SIA process. The findings of this research suggest that improvements to the outcomes of this process will require companies to act beyond compliance. However, these improvements may also ensure mining companies maintain their social license to operate and to ensure continued influence across the life of a project to closure.CITATION:Hill, H, Clark, P and Everingham, J, 2012. æThere is an emptiness for Maori here in WaihiÆ - Understanding indigenous perspectives on post-mine land uses in closure planning, in Proceedings Life-of-Mine 2012 , pp 153-160 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By J M. Dwyer, S Williamson

Acceptable post-closure performance of decommissioned mining operations is a critical factor in persuading todayÆs environmentally conscious public that the mining industry will not continue to burden future generations with the legacy of environmental tragedies. Post-closure impacts must be identified and managed through robust engineering design if the post-closure environment is to be environmentally sustainable. To manage potential post-closure risks (environmental, health, safety, social and economic) within acceptable limits, WMC incorporates a risk-based approach to closure planning and engineering design. WMCÆs risk-based closure engineering design process provides a simple methodology for developing robust closure plans û the process æengineers outÆ unacceptable risks and æengineers inÆ a sustainable post-closure environment. Benefits of the risk-based process include stakeholder endorsed closure criteria for an agreed post-closure land-use, focusing of resources on major risks, and a realistic and accurate estimate of the required closure provision. The outcome is an increased likelihood of satisfying the three pillar goals of sustainable development û a financially sound solution that poses a low risk to the environment and future generations.

Jan 1, 2003

By K Ehrig, V Liebezeit, E Macmillan

The results from metallurgical test programs are used in feasibility studies for design of new plants and brownfield expansions, in long term mine plans, and to make decisions in an operating plant. There are many elements which contribute to a well-constructed test work program. Ultimately, understanding the accuracy and precision of the test work results is critical to ensuring good decision-making at various phases of a project.Every resource drilling and associated assaying program will have a quality assurance / quality control (QA/QC) component, however this often seems to be overlooked in metallurgical testing programs. The principles of “international standard” or “certified reference material” samples and replicate/duplicate testing can be applied to metallurgical programs, although there are metallurgical-specific considerations in both generating and analysing the data.This paper will describe the QA/QC program carried out within the Olympic Dam geometallurgy program. It will present results in the form of case studies from ten years of testing of replicates and bulk reference samples for industry-standard comminution tests as well as laboratory flotation and leaching tests. The Olympic Dam geometallurgy quality control program has enabled quantification of the precision of metallurgical testing and improved our understanding of the best possible modelling results given the underlying dataCITATION:Ehrig, K, Liebezeit, V and Macmillan, E, 2017. Metallurgical QA/QC – who needs it? The Olympic Dam experience, in Proceedings MetPlant 2017, pp 31–44 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By I Canbulat, J Emery, L Yao and C Zhang

This paper documents a process of data analytics and machine learning applied to coalmine roof convergence data. It follows a publication documenting the formation of the database. For each set of analyses Python scripts were utilised to extract data from an SQL database, with subsequent analyses also executed in Python, utilising open-source tools such as scikit-learn. Preliminary analyses with classic machine learning algorithms included multiple logistic regression, K-nearest neighbours, decision tree, random forest, support vector machine, kernel support vector machine, artificial neural network (ANN), naïve Bayes and multiple linear regression. Results indicated that relationships were complex and non-linear, with the artificial neural network most suitable. An ANN model was then refined through a standard process of hyperparameter optimisation and data augmentation to arrive at a final model. Due to the black box nature of the ANN further insight into how the parameters interacted was sought and found with Shapley additive explanations (SHAP values). SHAP values utilise Game Theory, where each input parameter or feature is a ‘player’ while the data set is the ‘team’. The SHAP value is the impact of each player on the target value, essentially establishing the contribution of each input parameter. The results from all analyses are delivered in the paper, together with insights, applications, strengths, and limitations of the methodology.

Nov 29, 2022

By E Widzyk-Capehart, T Bednarz, O Daud, N Cutmore

The interest of industry, in particular future mining, is pointing towards the use of novel visualisation systems to improve the operational efficiency of user interfaces. While the technologies used to enhance operators’ experience are advancing, the implementation of novel visualisation paradigms within mining operations is trailing behind other industries, particularly health and aviation. In this work, we present a number of initiatives and use cases of immersive virtual and augmented reality systems that can fit within the mining context. These ideas represent a step towards new platforms that might increase the efficiency and safety of mining operations through applications such as 3D panoramic video monitoring technology with annotated information coming from big data analytics and visual analytics processing engines. However, while the technologies are used in a variety of training settings, their application in the working environment is lagging behind. This paper presents examples of scientific visualisations that could be applied in a mining context to extend the possibilities of operators’ cognitive abilities and working efficiency. They are intended to foster a discussion within the mining community to move beyond the training realm and into the operational environment.CITATION:Bednarz, T, Widzyk-Capehart, E, Daud, O and Cutmore, N, 2015. Effective immersive visualisation systems for mining applications and beyond, in Proceedings Third International Future Mining Conference, pp 31–36 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By G Cao, Y R. Cui, J X. Zhao, H P. Gui, G H. Wang, Z M. Wang, M M. Ren, B Li

Pyro-metallurgy is still the main process for lead production and a lot of lead direct smelting processes have been developed in recent years. All the processes will experience two steps in common. The first is the oxidisation of PbS to PbO and then reduction from PbO to Pb, furthermore, from ZnO to Zn. So, the composition of melts, especially the slag composition at reduction step change continuously. Up to now, there are few systematic results on the slag physical-chemical properties with its composition change. In this work, the typical lead direct smelting processes were analysed from theoretical and practical standpoints. The full-period slag composition and slag melting point change were compared. Especially, to the PbO and ZnO reduction steps, based on the full-period slag composition change, the slag properties were predicted. Based on dust composition and test results, the mechanism of Pb compound evaporation and its effect on practice and measurement of high PbO bearing slag physical-chemical property is discussed. It is suggested that to restrain the evaporation in practice and to obtain more accurate measurement results of physicochemical properties of smelting slag are the key problem not only to set high efficiency, energy saving process, but also to environmental pollution control.

Aug 21, 2024