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By D Stepanenko, G Stovpchenko, L Lisova, D Togobitskaya, L Medovar

Classical electroslag remelting of consumable electrodes is a drop-by-drop melt feeding through a slag layer into a renewing molten metal bath, slowly solidifying into a homogeneous, dense, defectfree ingot in a copper water-cooled mould. The new look at the additive nature of the electroslag remelting (ESR) process in a protective atmosphere allowed us to formulate the principles of a comprehensive thermodynamic-based model that can predict dynamic changes in slag and metal composition at certain ingot remelting. The model considers drastically different slag-to-metal mass ratios at the beginning and end of remelting and predicts gas, slag and metal composition in a chain of thermodynamic subsystems. Despite consisting of calcium fluoride and stable oxides, the ESR slag can oxidise main and active elements from steel and alloys (primarily aluminium, titanium and silicon) due to chemical reactions between slag and metal. ESR is not an electrochemical process in its nature. However, slags are ionic melts and deviation in their composition causes a change in their properties, affecting both operation mode and ingot quality. Another important understanding derived from the modern metallurgy technological route is that the ability to refine metal from impurities is not a priority for the ESR because consumable electrode has already passed all stages of refining and deep degassing at ladle treatment that changes ESR slags engineering principles. The critical importance became slag’s ability to generate process heat and keep the melting composition in the metal bath unchanged (except for non-metallic inclusions assimilation). Slag engineering for ESR required a compromise between chemical inertness to a metal composition and desired physical properties deriving from technological reasons. The Directed Chemical Bonds Concept (DCBC) in a multicomponent oxide system was used to build predictive models of electric conductivity and the melting temperature of fluoride-oxide slag based on their chemical composition. Both models help to design a customised composition of effective slags for steel and alloy groups or individual grades, and they are significant steps in the development of a comprehensive model of electroslag remelting.

Aug 21, 2024

Comprehensive occupational health and safety legislation in Australia is comparatively recent. It follows the examples set in U.S.A. and U.K. a decade or more ago. In Western Australia the Occupational Health, Safety and Welfare Act was proclaimed in April 1985. It still has a long way to go before it achieves all its objectives. The mining industry has developed a substantial body of health and safety regulations under the Mines Regulation Act. Considerable practical expertise in such matters already exists, much of it developed from hard won experience. As a result it would prefer not to become engulfed in the new legislation. It would prefer to build upon the cooperatively developed policies and workable practices in the field of occupational health and safety with which it is familiar. Associated Minerals Consolidated Ltd. is a leading mineral sands producer in Western Australia and has continuously developed its occupational health and safety policy and practices. Under the banner of "Resource Control", AMC seeks to provide a safe and healthy working environment at all times. This is being achieved through a strategy of a policy, a defined organisational structure and a detailed programme, which together comprise the "Resource Control System". Some of the activities and achievements of AMC in the field of occupational health and safety are compared with the objectives of contemporary legislation, and details of some of the specialised areas of the Resource Control Programme are discussed. The paper will also highlight and discuss impractical areas of potential legislation.

Jan 1, 1986

The optimisation and validation of shearer cutting methods is a time consuming engineering task. Many different parameters, of which not all can be controlled, can vary. The easiest solution, to increase the installed power and the longwall length, is not always the best. A different cutting method can increase the capacity without the need of new machines. The Department for Mining and Metallurgy Machinery at RWTH Aachen University therefore developed ProSL, the simulation tool for shearer and longwall operations. ProSL enables the engineer to create his own cutting methods and compare it with other methods. Machine-data can easily be varied to see the impact on the method. The research shows that sophisticated longwall methods increase the productivity of the system. The paper presents the results of the calculation with ProSL and shows how higher efficiency and lower costs can be achieved.

Dec 6, 2010

By M Flanagan, T Sua, B Wright, T Carroll, B Van Dijken

"BHP Billiton (BHPB) West Australian Iron Ore (WAIO) conducts an extensive geometallurgy (geomet) program for its iron ore deposits in the Pilbara. The geomet program provides accurate information to infrastructure engineers, resource geologists, mine planning engineers and the technical marketing team on the performance characteristics of iron ores. Performance metrics include production planning, such as lump/fine splits, processing capability such as the level of ultra-fine iron ore and ironmaking blast furnace properties including tumble index (TI) and reduction disintegration index (RDI). Prior to the introduction of the current geomet program in WAIO, basic geometallurgical information was provided at the deposit level, such as deposit lump percentage and head grade chemistry. As the business value of geometallurgy was realised during the growth period of WAIO, the geomet process was reviewed and formalised into five steps: geomet drill planning laboratory measurement data management algorithm development block estimation.The geomet laboratory process produces simulated iron ore products from drill core, which are then subjected to physical geometallurgy test work. With the large amount of geometallurgy data collected, extensive databases are utilised to collate and organise the data to improve its usability within the business. Algorithms are created from the data to predict important geomet variables and a block estimation method is used to estimate geometallurgical properties into resource models. The predicted geometallurgy data is regularly reviewed at the different steps against plant and shipping data to allow refinement of the geometallurgy algorithms. It is also recognised that geomet data can be used to optimise the operations in existing processing hubs for improved production rate. In addition, future geomet programs will focus on generating data from all available drill core programs, not just dedicated geomet drill holes, and will incorporate new types of data, such as hyper-spectral information, for improved geometallurgical estimation.CITATION:Wright, B, Carroll, T, Flanagan, M, Sua, T and Van Dijken, B, 2013. BHP Billiton West Australian iron ore geometallurgy - past, present and future, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013, pp 105-110 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 29, 2013

Tertiary laterite is extensively developed in the Darling Range area, but there is doubt that. the high relief areas along the Darling Scarp have been peneplaned. Three distinct laterite types are distinguished which are termed transported, introduced and residual laterites to avoid ambiguity. Transported laterites are recemented (primarily) lateritic materials and introduced laterites are chemical deposits of bog iron type. Residual laterites are formed in situ from the host material which can be either decomposed bedrock or detrital' clay, and the two varieties formed from these sources are termed residual A and residual B laterites. The genetic requirements for residual laterite formation are (1) host material, (2) porosity and permeability, (3) rainfall, (4) temperature, (5) relief and drainage, (6) vege- tation and (7) time. Previous theories on the origin of laterite appear to be inadequate and incompatible with field observations. Field investigations and drilling in the Darling Range area disclosed lenticular section and thickest laterite development on slopes and thin or oc- casionally no laterite development on crests. Lateritisation is considered a surface feature and the end product of the chemical weathering cycle. The relief and rain-water acting on a kaolinitic host material are con- sidered the major contributing factors in the

Jan 1, 1973

By H Arvidson, A Walker, N Pollock

Following the recent tailings tragedy in Brumadinho, the Investor Mining and Tailings Safety Initiative was formed representing institutional investors in the mining industry. This Initiative, led by The Church of England (CoE), requested data from 726 mining companies on each of their Tailings Storage Facilities (TSFs). What this exercise confirmed was that there was no public database of TSFs, and that there was a clear gap in tailings management systems within the disclosing companies. We present an approach using technology to support best practice TSF management, governance and disclosure which was originally submitted as part of University of Cambridge Post-graduate studies in Sustainability Leadership in January 2020. The aim of the paper is to discuss how technology could be used to deliver a Tailings Management Solution (TMS) that is aligned with the Global Industry Standard on Tailings Management (GISTM), and supports rigorous governance leading to disclosure. Subsequently the goals of the plan are aligned with that of the co-conveners of the GISTM (the International Council on Mining and Metals (ICMM), Principles for Responsible Investment (PRI) and United Nations Environment Program (UNEP)) which is to facilitate operators’ trajectory towards zero harm to people and the environment. Most of the focus to date around tailings management post Brumadinho has been on monitoring technologies, of which there are many. It is obviously important to acknowledge the critical role of monitoring technologies; however, our approach is agnostic to monitoring technologies and assumes that all of them are relevant. Our focus is on the data management, reporting and governance leading to disclosure of the information. Critical components of developing the TMS include adapting existing software products and solutions, recognising a system thinking approach is needed, strategic partnerships to deliver an accessible solution faster and more cost effectively, and, new ways of collaborating. The TMS should also accommodate relevant regional geotechnical codes and standards. The industry need for a TMS is well established and urgent, with significant pressure from regulators and civil society for the industry to address this significant issue.

Jul 1, 2021

By O Ignatenko, A van Schaik

Environmental legislation for the process and manufacturing industries is frequently formulated without considering the fundamental limits of physics, chemistry and thermodynamics within process technology. Recycling of end-of-life goods is used in this paper to show how the limits can be evaluated on the basis of the theory of minerals processing and metallurgical engineering. This theory has been applied on European Union level to re-examine the legislation for automobile recycling in a recent stakeholder discussion involving the automotive industry (http://www.assurre.org). This theory and our models are finding their way into the computer aided design (CAD) tools of the automotive industry, developments that form part of a project to design the super light car of the future (http://www.superlightcar.com). Only such fundamental approaches will in future be able to provide the basis to argue and define realistic and sensible environmental legislation.

Jan 1, 2006

The price of oil and other minerals may not make the costly business of offshore exploration seem -attractive at present. There is little doubt that the future search for the strategic resources will tend towards deeper waters particularly on the continental slope margins. In addition with the realisation that active tectonic environments (eg the Makassar Straits) cannot be excluded as potential hydrocarbon sources there is an increasing demand by the explorationists for deep water survey capability. Such deep water research has until recently been restricted to a few specialised academic institutions ;however with the anticipated extra, demand from other institutions, companies, and government agencies, Marconi Underwater Systems Limited (MUSL)and the Institute of Oceanographic Sciences in the UK have come together to allow MUSL to provide the deep water mapping system GLORIA on a commercial basis -for the first time. The GLORIA package comprises a deep water(more than 400m) side scan sonar system which, by operating at a frequency around 6.4 kHz can insonify swathes on the seafloor up to 60 km wide. In addition, single channel seismic, 3.5 kHz high resolution profiles, precision echo sounding, magnetic and gravimetric data all combine to provide as complete a regional interpretation as possible. The GLORIA system combines surveying at a reconnaissance level, covering as it does up to 20,000 sq.km per day, with a very high reliability, so that even in- economically unfavourable times, it can-still be considered as an invaluable and cost effective primary exploration tool. Analysis of the GLORIA data enables the identification of areas of particular interest requiring more detailed study by the more costly multi-channel seismics at a later date.

Jan 1, 1987

By S Vearncombe

SpaDiSÖ is a revolutionary approach to the spatial analysis of point data using geometry to analyse geometry! SpaDiSÖ uses each and every spatial relationship and is not dependent on mathematical models. For n points there are n2 û n spatial relationships and, because of the square function, the method yields interpretable results for both small and large data sets. SpaDiSÖ is an alternative to variography for directional studies. At the regional scale, the analysis can assess distribution patterns of mineralisation and potential controlling structures. At the deposit scale, the characteristics of zones of mineralisation such as direction, spacing, high-grade ore direction and grade distribution can all be deduced.

Jan 1, 2000

The refractory industry in New Zealand is small, consisting of two main manufacturers - one at Huntly and the other at Kamo. Together these would have an annual refractory production of about 30 000 tonnes. The industries which use refractories include two steelworks, NewZealand Steel Limited and Pacific Steel Limited, the former is involved in continuous casting from sponge, iron and scrap steel and the latter is involved in ingot teaming from scrap steel and steel billets; One aluminium smelter, cement works, dairy companies, small foundries producing engineering requirements and many other small users. The New Zealand manufacturers produce refractories in thefire brick range, that is up to 50 per cent alumina content (ignited basis), based on indigenous raw materials and in the high alumina range up to 85 per cent alumina content (ignited basis) based on imported bauxites. All of the basic refractories high purity silica and high alumina low alkali refractories and many of the higher grade acid resisting refractories are imported.

Jan 1, 1976

Background A recent development in many industries,' including the mining industry, has been ever increasing acceptance and adoption of extended (12-hour) shifts and compressed work cycles compensated by more time off work by employees between cycles. In the Western Australian mining industry development of `long-distance-commute' (LDC) coincided with adoption of 12-hour rotating shifts. Preludes to LDC were the `construction-style' rosters with two crews plus allowance for annual and sick leave relievers working the statutory 13 consecutive shifts followed by one shift off. Crews rotated day to night shift weekly or at fortnightly intervals. Average hours of 72 to 78 per week were common. The author had personal experience working these rosters in the East Pilbara of Western Australia from 1977 to 1982. Workers tolerated these rosters until a suitable combination of frustration, boredom, despair and the `Five Grand Fever' triggered them to `pull the pin' and head for relaxation in Bangkok, Manila, Nimbin, or Margaret River according to their personal tastes.

Jan 1, 1996

By S Udayakumar, S Biswal, N Sarmadi, V Sahajwalla, F Pahlevani

Recent times have witnessed a notable momentum in the interest surrounding technology dedicated to harnessing waste as valuable resources, prompted by the mounting challenges posed by waste accumulation and the swift depletion of natural resources. The carbon dissolution process within a molten iron bath stands as a pivotal reaction within the metal processing sector. The current study explores the utilisation of waste graphite electrodes (WGE) (obtained after being utilised in an electric arc furnace) as a secondary resource of carbon for dissolution into liquid iron. Experimental investigations were carried out at 1550°C using the sessile drop approach. High purity iron powder was used and the carbonaceous substrates were prepared from the ground WGE. The carbon pickup was determined using a suitable carbon analyser. Furthermore, an examination of the interfacial area between the molten iron and the WGE substrate was conducted beneath the metallic droplet, which effectively represents the iron/carbon interface. This interfacial analysis was carried out on two different samples obtained after a varying period of heat treatments at 1550°C. The interface layer was investigated using scanning electron microscopy (SEM) in conjunction with energy-dispersive X-ray spectroscopy (EDS).

Jun 19, 2024

By G McKay, M Erskine, S Macklin

The City of Sydney is currently investing in a number of infrastructure projects that require tunnel excavations within the Triassic Hawkesbury Sandstone. It is generally accepted that this formation has high residual stresses of ‘tectonic’ origin, so much so that these stresses have been implicated in a number of well-known failures and problems for tunnelling. These include failure of ‘roof beams’ comprising discrete beds in the crown of tunnel excavations; stress-induced spalling and ‘slabbing’ of tunnel walls; shear displacement between beds causing the failure of rock bolts; strain in adjacent infrastructure and, the necessity for re-grouting of high conductivity fractures due to stress relief dilation after excavation. Whilst there is an extensive published database of in situ stress measurements comprising ‘hydrofrac’, ‘over-coring’ and ‘slotter’ stress measurements, these data indicate a considerable spread of results. The traditional approach to interpreting this data has been to attempt to fit linear correlations to stress versus depth data, based on personal experience and ‘back-analysis’ of monitoring data during construction. However, there are a number of such correlations in the literature and there is divergence of opinion regarding the assessment of ‘background’ in situ stress and appropriate upper and lower bound values for design. This paper provides a brief review of the published data; suggestions on an alternative ‘risk-based approach’ to assigning in situ stresses for design; and, proposals on how in situ stress tests may be conducted in future to improve the quality of the database available to designers.CITATION:Macklin, S, McKay, G and Erskine, M, 2014. A review of the in situ stress database for tunnel design in the Hawkesbury Sandstone, Sydney, New South Wales, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 171–178 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By M Haest, O Dominguez, D Mittrup

Technological innovations and emerging analytical capabilities are transforming the way drill samples are analysed, with real-time mineralogical analysis made possible. In addition, new business/technical requirements are challenging long standing processes to incorporate more sources of information during planning in order to improve compliance to plan during mining and processing. Unfortunately, the new sources of information that are added do not always have adequate protocols in place to ensure quality data is collected.Spectral data covering the visible – near – short wave – midwave – longwave range are routinely collected by the Geoscience and Exploration department at BHP Billiton Iron Ore for accurate mineralogical identification. These data are used for geological interpretations (logging and modelling) and prediction of physical variables (metallurgical and geotechnical properties).This paper introduces how sampling and quality assurance / quality control concepts have been applied in the spectral data process. The described routine for sampling, data collection/management and reconciliation has been developed to track system precision and accurately and consistently ensure the data is of high quality before it is used across the mining chain.CITATION:Mittrup, D, Dominguez, O and Haest, M, 2017. A new approach to implement quality assurance and quality control to technological innovations – quality of spectral data capture and processes in the minerals industry, in Proceedings Eighth World Conference on Sampling and Blending , pp 265–270 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

The last two years have seen a rapid change-over from mechanised cut and fill. stoping to the more economic and productive long hole open stoping method, such that today more than 80 per cent of total production is won from open stopes. At first drilling was by sub-level rings and/or parallel up and down holes from inter- mediate sill horizons using conventional exten- sion rod equipment. Sub-levels were developed no more than 40 metres apart to allow accurate drilling. Compact, crawler mounted in-the-hole hammer equipment was introduced as soon as it became available in Australia. Today, all open stope drilling is done with three Atlas Copco ROC306 rigs and two Ingersoll-Rand CMM jumbos. Fans of 115 mm diameter holes, varying from near vertical down holes to horizontal, are drilled with a burden of 3 m. Toe spacing varies from 3.5 m to 4 m. An Atlas Copco DG418 booster compressor is used to boost run-of-mine air from 700 kPa to 1400 kPa in the areas of longest drilling. This has improved overall drilling performance in these areas by 40 percent.

Jan 1, 1977

The economic future of the Palmer Goldfield lies with both the gold mining and the tourist industries. An equitable solution to the competition between the two involves putting a dollar value on the historical evidence there for our Australian heritage.On 23 October 1986 the Queensland Government gazetted the Palmer River Reserves R16 of 16 200 hectares, in recognition of the competing land uses emerging in the region. The intention is that historically significant gold mining sites and relics will be preserved in situ with provision for continued gold exploration and mining.This paper explores and explains the administrative process of achieving a set of Management Guidelines for Rl6 within the Queensland political milieu. The result of that process is the achievement of some of the highest preservation standards in Australia, prohibiting surface disturbance of defined Category 1 sites, and no mining proposal has yet been refused approval.The Palmer Goldfield R16 experience is a major step in achieving a co-ordinated approach to both current mining and preservation of Queensland's mining heritage.

Jan 1, 1990

By E Hondros

Innovation and Business Skills Australia (IBSA) commissioned The Boston Consulting Group (BCG) to undertake a study into how the role of AustraliaÆs senior managers is likely to change between now and 2020 and to identify the skills and attributes that will be needed to respond to those changes. This report builds on a previous study prepared by BCG in the early 1990s for the Industry Taskforce on Leadership and Management Skills (Karpin Committee), which provided a snapshot of the Senior Manager in 2010. The following powerpoint slides summarise the 2020 Vision û The Manager of the 21st Century û outlining how the role of AustraliaÆs senior managers is likely to change between now and 2020 and to identify the skills and attributes that will be needed to respond to those changes. The presentation is summed up in the following quote from Jon Nicholson û Senior Vice President of BCG: We believe that to succeed in the years up to 2020, executives will need to master a range of hard and soft skills. Amongst other things, they will require to manage multi-generaional teams, the creativity to measure staff performance on outputs rather than inputs, and a high degree of technical and functional expertise in addition to their general management credentials. This paper is available as a PowerPoint presentation only.

Jan 1, 2006

By G Williams

Somewhat to the surprise of many heavy mineral sands (TiO2 and zircon) producers, there are important geological structures within their typical placers and aeolian sands deposits that affect plant metallurgical performance. After many years of operations, even experienced producers have encountered unexpected changes in production, product quality and recovery. After looking in all the obvious (but wrong) places, it is recognised that the mine has advanced into ore with different separation characteristics. Metallurgical process response can vary significantly between ore sourced from different geological domains. The mineral characteristics that are exploited for effective separation may be associated with differences in the depositional environment, or be post-depositional in origin. Surface coatings that interfere with electrostatic separation might be associated with paleo-water table movements. Major storm events in the deposition history can also leave distorted mineral assemblage through stranded formations or incisions in older deposits.Apart from the influence on capital and operating costs, geometallurgical variances add another dimension to orebody modelling. Each domain could have specific recovery, mineral assemblage and product quality values to be considered in the value model. Project success is often directly dependent on understanding the geometallurgy of the resource. Tailoring the exploration and early process flow sheet development programs to account for such variances should be standard practice. Such practices have had a chequered history in the mineral sands industry, with sophisticated processes having been developed, only to be shelved for ‘economic’ reasons, and then once again ‘discovered’ when problems re-emerge.It is clear that knowledge gained through a higher level understanding of the changing mineral separation characteristics and advance warning of mineral behavioural differences can mean the difference between lost recoveries and disappointed customers or well timed capital plans and maximised revenues.

Oct 5, 2011

By B King

A large number of mineral deposits contain regions in which it is economically beneficial to extract ore both via open pit and underground mining techniques. Current industry practice lacks an effective means to establish the extent of the open pit and underground mining areas for an individual deposit. We present a mixed integer programming model for scheduling both the open pit and underground mine that can be used to create a holistic extraction sequence for a specific deposit. The model considers both spatial and temporal elements of the open pit and underground mines in order to maximise the net present value of the entire deposit, while adhering to its production, processing and block sequencing constraints. By doing so, we can schedule the open pit and underground in concert.CITATION:King, B, 2014. Modelling open pit and underground production scheduling in concert, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 369–374 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By S Bright, M J. Masamvu, E K. Chiwandika, S Dandi, S M. Masuka

The depletion of high-grade hard and lumpy chrome ores has forced Zimbabwean ferrochrome producers to resort to low-grade friable ores that have an average of 28 per cent fines against a set limit of 12 per cent. Submerged open arc furnaces currently in use are associated with eruptions within the furnace because of the high amounts of fines, high energy consumption, as well as high SO2 and CO2 emissions. Traditionally employed agglomeration methods such as pelletising and the use of coke in the furnace have been discarded because of the pressure to lower operational costs and to achieve higher profit margins. This research aims to develop a method to incorporate lowgrade friable ore fines and unprocessed coal into production while lowering CO2 and SO2 emissions through a closed direct current (DC) arc furnace. The closed DC arc furnace could incorporate the friable ores and coal while maintaining above 90 per cent reduction rates. Preliminary findings also show that energy consumption could be reduced by up to 35 per cent by incorporating a pre-heating and pre-reduction system using the flue gases from the furnace. In the proposed circuit, the cost of production per ton of ferrochrome might be potentially lowered by an average of 30 per cent.

Jun 19, 2024