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By C Grobler, M Recklies, G Jiang, I Taylor, M Morgan, G MacDonald, L Smith

The resource estimation of lateritic deposits, such as Aurukun, presents specific issues related to the lateral changes in thickness and elevation of the various horizontal layers (or zones) within the deposit where the x and y dimensions are orders of magnitude greater than the z dimension. The objective was to develop a three-dimensional (3D) block model that retained the vertical and lateral variation inherent in deposits of this type to allow full optimisation of the production plan without prior selection of an economic portion (enriched bauxite layers) of the profile at the resource estimation stage. The Aurukun bauxite deposit is held by Chalco Australia Pty Ltd (Chalco) and forms part of the world-class Weipa bauxite province, Cape York Peninsula, Queensland, Australia. The bauxite is predominantly pisolitic with an upper boehmite-rich zone and lower gibbsite-rich zone. The bauxite consists of both in situ and reworked domains, is overlain by a thin soil horizon and has kaolinite clay as a transitional base. A portable infrared mineral analyser (PIMA) was utilised on site, in addition to elemental assay, on each drill sample to determine the mineralogy, in particular levels of boehmite, gibbsite, kaolinite and reactive silica. As part of the scope of work, a field program was undertaken using large diameter Boart Longyear sonic drilling to acquire detailed density measurements across the deposit to allow compliance with Joint Ore Reserves Committee (JORC) reporting requirements. Interpretation of the stratigraphy was conducted on a hole by hole basis with definition of the zone layering based on stratigraphy, geochemistry and mineralogy. The zone boundaries were then modelled as 3D surfaces and used to constrain a block model. The block model estimation used the ordinary kriging method, with the estimation done in unfolded space and then refolded, therefore maintaining the zones irrespective of thickness or orientation. The unfolding process converts the real-world positions for both blocks and informing samples to a scaled position relative to the roof and floor of each zone. Analysis of the data and variography were also undertaken in unfolded space. The x and y dimensions are unchanged, but the z dimension is a relative position. The effect of the unfolding and limits on number of samples per hole is to æpushÆ the informing sample search sideways but within the stratification, rather than vertically. This honours the strong vertical zonation within the bauxite profile. The JORC Code requires that the stated resource must have æreasonable prospects for economic extractionÆ. This is a qualitative rather than quantitative definition. A number of selection criteria to define a resource roof and floor were developed in consultation with the project engineers and owners to meet these criteria. The vertical selection of material to include in the resource highlights the variation in the development (and destruction) of the bauxite profile from area to area within the deposit.

Jan 1, 2009

By Drinkwater DJ, Watsford RMS, Johnson NW, Munro PD

This paper describes the use of modelling and simulation techniques in the analysis and optimisation of grinding circuits at the Lead/Zinc Concentrator of Mount Isa Mines Limited.The objectives of the studies were to: -1. improve primary grinding circuit performance by reducing the production of -0.006 mm galena fines.2. maximise the fineness of grind in the second existing grinding power and pumping capacitie The study has shown that quantitative models can operations. The models described plant operation,,and simulated the effect of process changes on plant performanc The use of automated scanning electron microscope technology tcliberation characteristics of the major minerals in the Mount isa Lead/Li ore is also described.

Jan 1, 1985

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

By J L. Kerr, J Beyer-Robson, S Vink

Driven by an increasing need for water conservation, coal mine operators in the upper Isaac River catchment have placed significant emphasis upon the reuse of water. This initiative led to an overall increase in the salinity of mine waters. The ionic composition of this water differs from local stream water in that concentrations of sulfate are higher than average stream concentrations by ten per cent, while concentrations of bicarbonate and calcium are lower. When this water is discharged into ephemeral streams in semi-arid environments there is potential for this increased salinity and altered ionic composition to impact upon the ecosystem processes mediated by micro-organisms in river sediments.We have measured nitrification, denitrification and methanogenesis rates in a series of lab experiments using sediments from Isaac River catchment streams and found that salinity affects these processes in different ways and to different degrees. Process rates were shown to differ seasonally between samples taken from the same location and habitat type and also between different habitat types at the same time and location. Both aerobic and anaerobic process rates were higher in surface sediments and it is likely that this activity is associated with surface biofilms. Furthermore, we have shown that the ecosystem processes we have measured are limited by the availability of carbon in the sediments.The management implications of these findings for mine releases into ephemeral streams will be discussed.CITATION:Kerr, J L, Vink, S and Beyer-Robson, J, 2013. The effects of increased salinity on microbially mediated ecosystem processes in ephemeral streams, in Proceedings Water in Mining 2013 , pp 121-134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 26, 2013

Three major and two minor uranium deposits 'have been worked by open out mining since the discovery of ,the Rum Jungle field in 1949. Total production has been about 9679000 tons of uranium ore at 7;39 lb U308/ton and 4029000 tons of copper-uranium ore at 6.27 lb U308/ton and 2.7% Cu, with significant tonnages of base'metal ores. The deposits occur in or near black pyritic slates of the Lower Proterozoic Golden Dyke Formation, near the contact with the under- lying Coomalie Dolomite. The mineralization is probably younger than the grahite complexes in the area, and a structural-stratigraphic control of ore deposition is used as a basis for uranium exploration.\

Jan 1, 1968

By S Brochot

During the development of a mining project, samples are taken for metallurgical tests. The sample can be a composite sample made of material coming from a selection of various drilling products or a sample coming from a mining test. This sample can represent several tonnes of material which are analysed and split to be used in various tests.In the current case, a composite sample is dedicated to semi-autogenous grinding (SAG) pilot plant tests. The property of interest is then the size distribution of the material. The sample is mixed and a subsample is taken to measure the size distribution which is considered as the feed size distribution. Then the remaining material of the sample is divided in several subsamples for batch grinding tests at different operating conditions. The product of each grinding test is then analysed to measure its size distribution.The grinding performances are analysed at the light of the measured size distributions for feed and product. But what is the accuracy of the measurement of these size distributions? What is the variability of the feed knowing each feed is just a subsample of the initial sample?The Pierre Gy theory of sampling answers these questions.The current paper presents, through a real example, the calculation of the measurement error of the size distributions and the variability of the feed between the different tests. The uncertainties of the grinding performances are then calculated and their impact on the results interpretation is then analysed.CITATION:Brochot, S, 2012. Sampling for grinding pilot plant test - the effect of size distribution variability, in Proceedings Sampling 2012 , pp 127-134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By B Bradák, D Asahina, S Saydam, S Akdag

Human exploration of Mars has been on the horizon of scientific goals for decades now, and as part of the objectives of human missions to various planets, one of the possible goals is opening new economic frontiers by the potential extraction and utilisation of resources, eg mining minerals and using surface regolith (Neukart, 2024). A comprehensive understanding of surface morphology, lithostratigraphy, basic structural geology, and civil engineering technology is essential to conduct mining operations for resource extraction on extraterrestrial planets. For instance, proper assessment of the risks associated with excavation and infrastructure construction under unique environments such as low gravity, surface irregularities, and the presence of regolith is fundamental. Such knowledge has been accumulated through satellite imagery and numerical topographic data using remote sensing technology, as well as seismic surveys by the on-site lander (Knapmeyer- Edrun et al, 2021; Banerdt et al, 2020; Giardini et al, 2020). Recent studies show that Marsquakes could be caused by the release of strain energy generated by the contraction of Mars. In particular, Marsquakes occur around the graben where many faults exist and form regularly spaced patterns. This implies that Marsquakes occur when the stress field of the Martian crust is an extension condition, and normal faults appear on the surface. In this study, we focus on so-called graben structures, one of Mars’s common tectonic structures (Plescia, 1991; Banerdt et al, 1992; Hoogenboom Hagen, 2014). The study aims to provide additional information about the tectonic environment during the formation of such features and, in addition, the internal mechanical-rheological structure of Mars, revealed by the geometrical pattern of faults modelled and simulated in a laboratory environment.

Sep 1, 2024

By Lee H. G, Li H, Hayes P

Slag from the smelting of lead can contain up to 20 per cent zinc as an oxide. An understanding of the lead smelting process and of the subsequent fuming process for the recovery of zinc is enhanced by a knowledge of the activity coefficient behaviour of zinc oxide in smelting slags. The literature presents a wide range of contradictory values. This paper critically reviews the published data and outlines new measurements being made by the authors. A consistent set of zinc oxide activity coefficient data is presented for liquid slags within the ZnO-'FeO'-CaO-A1203-SiO2 system, through a combination of present and previous measurements.

Jan 1, 1993

By N Davies, M J. Coward, P L. Hissey

Mount Isa Mines has four mining operations in Mt Isa with the X41 and Enterprise Mines producing copper and the Lead Mine and George Fisher producing lead zinc and silver. Each stream contributes ore to their respective concentrator at a feed rate and therefore metal ratio set out by the monthly schedule. Mine Planning and scheduling lead to a sales and operating plan (S&OP) and revenue projections which ultimately derives actual revenue /tonne and therefore cost/tonne. At Mount Isa, both the copper and lead/zinc streams produce ore from relatively new operations to be blended with material from more mature operations. It is critical to accurately predict the metal contribution from each operation in order to gauge the relative performance of each mine. Development mining ore contributions are estimated and reconciled, as are stope and bench sources. Performance is continually measured and assessed during extraction and grade adjustments are made to account for underbreak, overbreak and design modifications. It is critical to not understate or overstate the contribution from one operation relative to the other as this can produce a false picture of operational performance. Identifying process improvements are key to improving the business overall. Ore from the lead stream passes 17 measurement stations and two midstream reconciliation points before delivery to the heavy media plant (HMP), where the metallurgical circuit begins. From this point two concentrates are produced. A zinc concentrate for treatment off site and a lead concentrate for further on site processing. The lead smelter takes 100 per cent of Isa concentrates as well as a contribution from BHP-BillitonÆs Cannington Mine.

Jan 1, 2002

Sampling and sample preparation systems at the Hamersley Iron Pty. Limited port of Dampier, W.A., were developed for two separate objectives. 1. The need for rapid determination of physical properties. On stream size analysis enables lump ore and pellet- ized ore physical properties to be monitored and controlled whilst shiploading is in progress. As a control procedure this facility allows optimum shiploading rates con sistent with physical quality control. 2. The need for accurate chemical analysis. Chemical analysis on ship- loading forms the final link in overall quality control procedures encompassing the operation of mining, railway and port blending. Thus maintenance of specification products with minimum variation in chemical characteristics is ensured.

Jan 1, 1976

By Christie AB, Bull VH

The geological environments of gold deposits are reviewed in relation to the strong resurgence in exploration for gold since 1979. The resurgence is due mainly to New Zealand's geological endowment with gold and its history as a gold producer. Major past production was from Cenozoic placers of Otago and Westland, late Cenozoic epithermal deposits of the Hauraki Goldfield, and the respective Paleozoic and Mesozoic lode deposits of the Reefton and Otago Goldfields. These same geological environments are the targets of current exploration, mainly in extensions of previously mined deposits. On the Westland and Otago Goldfields alluvial and fluvioglacial gravel placers, mainly representing lateral and depth extensions of previously worked ground, are being mined and prospected. Gold production in 1984 was exclusively from these deposits, and the development of mobile concentration plants has resulted in a great increase in mining activity. Mineralised zones adjacent to previously mined lodes in the Hauraki Goldfield, Reefton Goldfield, and at Macraes Flat (Otago Goldfield) are being intensively explored. At Waihi (Hauraki), an open-pittable resource of about 10 million tonnes of ore has recently been delineated. Some new deposit types and little explored environments are also receiving attention. They include: gold-sulphide quartz veins hosted in an alkaline granite dike in west Nelson; hot spring type gold deposits in fossil geothermal (epithermal) systems of Northland, the Hauraki Goldfield and the Taupo Volcanic Zone; and marine placers off the West Coast where an area of auriferous gravels has been outlined near Hokitika. There is potential in known deposits and prospects currently being evaluated for a large increase in gold production by the early 1990s.

Jan 1, 1986

Gallium occurs at above background levels in most samples collected from 11 of the major geothermal areas in the Taupo Volcanic Zone. Concentrations of Ga in the 48 samples ranged from 8 to 144 mg kg-1 and varies widely from place to place within each geothermal area. Gallium is contained within the alumino-silicate structure of clay in the mud, having substituted mainly for Al. Suggested deposition mechanisms for Ga also involve co-precipitation with Sb, As, and SiO2 colloids. Digestion trials, carried out to determine extraction conditions for possible commercial exploitation, showed that heating the mud to 500 - 600¦C for 1 hour followed by acid/alkali treatment gave complete recoveries.

Jan 1, 1995

By L Alem

In the field of mineral extraction, complex technologies are being introduced in mines, operators/technicians rely on assistance from an expert (or more) in order to keep their machines functioning. Personnel with such expertise, however, are not always physically on-site. There is a growing need for innovative technological solutions to support effective delivery, just in time, of remote guidance between an offsite expert and an on-site maintenance operator. To meet this need, we have, as part of our Human System Integration project within the CSIRO’s Minerals Down Under (MDU), Transforming the Future Mine theme, explored the usefulness of a number of emerging technologies including: augmented reality, wearable systems and touch table interfaces. This paper presents ReMoTe, an augmented realty system for remote guiding using a touch table interface for the expert station and a combination of augmented reality and a wearable system at the operator end. In designing this system we were interested in exploring the extent to which it can increase the productivity and safety of maintenance personnel. This paper also presents Mobile ReMote, our recent development of a fully mobile remote guiding system. In Mobile ReMote, both the expert and the operator are using a near eye display and wearing a light computer in a back pack. The expert is able to guide the operator using his/her hands on the virtual display, while the operator is able to see the instructions on the rear eye display. Workers in the mining industry are highly mobile, a mobile expert and operator station will meet this need.

Nov 22, 2011

By Schon RW, Stephens CJ

The Whitsunday Volcanics occupy most of the offshore islands from the Whitsunday Group, southeastwards through the Cumberland and Northumberland Groups, possibly extending to the mainland adjacent to Shoalwater Bay, a distance of 370 km. Some of the islands of this group are granitic, but preliminary Rb-Sr data indicate these to represent Permo-Triassic basement. Cretaceous volcanism is interpreted to have occurred during initial rifting prior to the continental breakup of northeastern Australia and subsequent development of the Tasman Basin.The volcanics comprise mainly lithic ignimbrites, with local development of inter-bedded surge and bedded tuff, accretionary lapilli tuffs, lithic concentration zones, and lag deposits. Isolated fluidual rhyolite and dacite domes occur. The deposits are considered subaerially emplaced. A Rb-Sr isochron age for volcanism of 110 Ma is determined from new data. The total thickness of the volcanics is unknown, but a minimum thickness of 4-5 km on Whitsunday Is. is suggested. Eruptive centres are inferred to be distributed throughout the volcanic zone. The volcanics are cut by numerous, dominantly near N-S, dykes ranging from dolerite through to rhyolite in composition.Chemically, the volcanics and dykes exhibit a continuous range of compositions from basaltic andesite, through andesite, dacite, to rhyolite, with minor more alkalic compositions. Phenocryst mineralogy in the silicic rocks is mainly plagioclase, augite, and Fe-Ti oxides, with less frequent quartz and hornblende occurrence. Sr and Nd isoptic compositions for volcanics and dykes are close to mantle values. These data are tentatively interpreted in terms of a lower crustal magma arc source separated from the mantle only a geologically short time prior to Cretaceous magmatism.

Jan 1, 1990

By P Hodkiewicz, K Noormohamed

Gold deposits in the Chirano district in south-west Ghana are hosted in a variety of structural settings along the Chirano shear zone (CSZ), in Paleoproterozoic rocks of the Sefwi-Bibiani belt. Most gold mineralisation occurs in strongly sheared and hydrothermally altered Birimian mafic igneous rocks and tonalite intrusions within the CSZ. A recent program of open pit structural mapping, core logging, and three-dimensional modelling helped to define deposit-scale structural controls on gold mineralisation. These include strain domains, shear zone flexures, shear zone intersections and vein arrays associated with host-rock competency contrasts. Interestingly, the plunge of higher-grade shoots in some deposits appears to be associated with the intersection of the CSZ and broadly folded Tarkwaian sedimentary rocks, which are not significant gold hosts in the Chirano district. This paper presents the results of 3D modelling that were used to define structural controls on mineralisation in several open pits and one underground mine along a 9 km length of the CSZ. LeapfrogÖ software was particularly useful because it highlighted the orientations of structural features that focused hydrothermal fluid flow during alteration and mineralisation. The improved understanding of structural controls provided two main benefits: near-mine exploration drill targets and better definition of structural domains for resource estimation.

Jan 1, 2009

South Crofty's ventilation network is large and complex. Of the total exhaust air quantity 40% enters the mine by leakage routes through old workings, this air carries high concentrations of radon gas and results in the mine becoming a classified work place under the Ionising Radiation Regulations 1985. Improvements in the control of the ventilating air and dilution by increased air quantity have reduced the average contamination to aelow-0.2 WL. The major part of the radon originates from ground water inflows and from concentrations of radium within the mine with direct emanation from rock surfaces being negligible. Of 600 kBgs-1 total radon leaving the mine 93% cannot be accounted for from known and accessible sources.

Jan 1, 1988

By L C. Thompson

A new understanding of the formation of black organic shales in the Illinois Basin has contributed to insights on how to produce methane from these complex reservoirs. These shales are far from simple shallow derived sediments but are in fact the result of a complex series of events which include the intermixing of volcanic detritus and the marine organic material, onlap successions and low energy turbiditic intraformational activity. This has led to a review of the commercial significance of the mid Devonian shales in the sedimentary basins of the eastern half of the USA. These shale sequences are also characterised by very little contribution from the underlying Lower Palaeozoic carbonate formations. The later diagenetic influences and the interaction of sea floor bacteria especially since the mid Devonian have lead to the creation of a major source of energy in the form of methane. Vast areas measured in 1000s of square kilometres are known to contain biogenically derived natural gas as methane. However, this vast resource produces very little gas due to abundance of illite which acts as a major adsorption mineral and creates a refractory situation where though there is abundant gas present the rate of release is clearly subeconomic. This paper will present the results of recent laboratory trials which have indicated that it is possible to create microfracturing using bacteria within the gas bearing shale sequence and also restart the methanogenesis process. As most coal bed methane environments have similar organically derived shales in direct relationship to the coal beds themselves then this paper has ramifications for this industry as well.

Jan 1, 2004

By Blain CF

For all mineral resource-based companies, it is important to reach the right balance of investment between acquisition and exploration to allow the best chance of achieving long-term corporate goals. The Broken Hill Proprietary Company Limited (BHP) provides an excellent example of success from generative exploration and supports the belief that exploration can be justified, not only in terms of investment criteria, but also because it is essential to a company wishing to build a dynamic profitable growth path based on world-class deposits as cheaply as possible. BHP was incorporated in 1885 to mine a lead/zinc/silver discovery at Broken Hill. The Company has since gone through a steel development phase (1911-1965) and is now in a major phase of growth partly based on exploration success. This third phase was marked by decisions taken in the 1950's to search actively for mineral and energy resources above and beyond the requirements of the steel industry. The commercial successes of this period have been Bass Strait oil and gas, Groote Eylandt manganese, Deepdale iron ore, Gregory coal and Carnilya East nickel. In total at least 22 new resource discoveries have been made in the last 25 years, of which 11 have been developed and several are undergoing feasibility studies. A financial analysis shows that the real value of the returns seeded by discovery covers the real exploration cost many times over. Moreover, the major discoveries have had a spectacular impact on the growth and development of the Company. BHP's present exploration effort is directed towards geological targets which most frequently meet attractive financial criteria and also promote diversification from steel-related earnings.

Jan 1, 1986

By Grant BPM

The lower levels at the CSA Mine have been developed to mine reserves between theNo.7 level and No.9 level.Work on major excavations for the project began during 1982 with the develop-ment of the crusher chamber, on No.9 level. The brows and walls were pre-dowelled to improve stability before mining by mass blasting techniques.At the same time work commenced on theextension of No.2 Shaft from No.7 level toNo.11 level. The shaft was stripped, using hand held drilling, to a raise bored holeand concrete lined to a diameter of 5.5 metres. Plats were developed at No.8 level, No.9level and the loading station.

Jan 1, 1985

The metals titanium and zirconium and their alloys occupy individually unique positions in the catalogue of metallic materials available for engineering applications. Because of the uniqueness of their usage in the aerospace industry, in the case of titanium, and in the nuclear industry, in the case of zirconium, the except- ional resistance of both the metals to the majority of corrosive media is often overlooked. The cost factor in the application of these more exotic metals has, in the past, been a major considerat- ion in the rejection of titanium and zirconium as constructional materials in areas of usage where their superior corrosion resistance strongly favoured them over more conventional metals and alloys. The cost differential, vis-a-vis austenitic stainless steels, for example, is not a trifling matter, being of the order of 6 : 1, when compared on a weight basis. However, if one considers the cost, for, say, sheet product on an area basis, the ratio is redgced to approximately 3.4:1. If one also takes into account the enhanced performance of the more expensive material and the sub- sequent increase in service life and decrease in plant down-time, the economics of the usage of materials such as titanium becomes much more attractive and, indeed, highly competitive,

Jan 1, 1969