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By A Yame, P J. Pollard, E Atase, J Garu, M Tangwari, D R. Hastings, R W. Smillie

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Townsville prospect is situated approximately 4 km north of the Ok Tedi copper-gold mine in Western Province, Papua New Guinea. Drilling in the 1990s delineated a resource of >1 Moz of gold within shallow, skarn breccia-hosted mineralisation associated with quartz-carbonate infill, together with pyrite, chalcopyrite, pyrrhotite, sphalerite, galena, tennantite-tetrahedrite, arsenopyrite, marcasite, and a variety of Au-, Ag- and Bi-telluride minerals. The deepest of these historical holes (TVL034) also intersected copper-gold-silver mineralisation more than 100 m below the gold-rich zone that is associated with calc-silicate skarn breccia. Although copper-gold-silver mineralisation in DDHTVL034 is associated with clinopyroxene-rich skarn, it was also noted that garnet in the skarn breccia became progressively darker in colour with depth, ranging from green at shallow levels to dark red-brown at depth. This indicated that the skarn breccia is zoned, with more proximal garnet skarn at depth possibly indicating an association with porphyry-style copper-gold mineralisation.Based on this skarn zonation model, recent drilling at the Titan prospect, located approximately 500 m south of TVL034, was targeted at potential copper-gold silver mineralisation beneath shallow skarn breccia-hosted gold mineralisation. DDHTVL 081 intersected 46 m at 6.36 g/t Au from 68 m and 80.7 m and 1.67 per cent Cu, 1.27 g/t Au and 20.32 g/t Ag from 184 m. Exploration is now attempting to define the extent of copper-gold-silver mineralisation by defining structural controls on the skarn breccia together with paragenetic and mineral zoning data.CITATION:Smillie, R W, Pollard, P J, Hastings, D R, Yame, A, Tangwari, M, Garu, J and Atase, E, 2015. Exploration of the Townsville Cu-Au-Ag skarn, western province, Papua New Guinea – preliminary observations of paragenesis and zoning, in Proceedings PACRIM 2015 Congress, pp 593–600 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By Barber J

The manganese ore of Groote Eylandt is a shallow sedimentary deposit of Cretaceous age. There are a number of deposits which vary greatly in ore texture, density, percentage of matrix and thickness. The thickness in the present five operating quarries varies from 1-5 metres. The mine output in 1973 was 3 million tonnes of which 60% was blasted, the remainder ripped and bulldozed. The shallow deposit and its varying thickness create rather unique blasting problems which must be overcome in order to produce a minimum overall mining cost but not necessarily resulting in a minimum drilling and blasting cost per tonne. Future planning envisages the introduction of site mixed slurry explosives following test work and the application of a twin boom single operator rotary percussion drill. The paper outlines the overall developments,present and envisaged practices and the reasons for these changes.

Jan 1, 1974

By Dobos SK, Gibson GM, Little TA, Sliwa R

Current studies, and analysis of previouslypublished data, have lead to a re-evaluation of the inclusion of the North D'Aguilar block within the "Gympie Province" in southeast Queensland. The metamorphic rocks are part of a Late Devonian(?)-Early Carboniferous subduction accretionary complex and are unconformably overlain by volcanic and coarse-grained clastic rocks of probable Early or mid-Permian age, as well as by Early to middle Triassic rocks of the Esk Rift. Metamorphic fabrics in the basement rocks include not only those that can be related to convergence, but also younger fabrics that may have developed during Late Carboniferous or Permian uplift and unroofing of the accretionary rocks. A predominance of basic schists, some of which are blue amphibole-bearing, and associated fine-grained pelagic and hemipelagic sediments in the Northern D'Aguilar block contrast with the siliciclastic-dominated sediments of most of the accretionary complexes of the New England Orogen. However the similarity of structural style, and metamorphic and igneous history, with adjacent basement blocks, and with other blocks throughout the New England orogen, suggests that the North D'Aguilar block simply represents deeper, probably underplated, levels of the same subduction complex. Uplift and cooling may have been accomplished by extensional faulting during Permian inception of the Esk rift, which flanks the block on the west.

Jan 1, 1990

By Yamakita T, Yoneoka Y

The Chigirishima Smelter of Toho,Zinc Co., Ltd. is the largest independent custom lead smelter in Japan and produces about 60,000 tonnes/yr of electrolytic lead. The quantity of slag produced by blast furnace is approximately 65,000 tonnes/yr, 30,000 tonnes/yr of which is sent back to the sintering plant for mixing with lead concentrates. The remaining slag used to be piled up at the yard until the operation of the fuming plant started in July 1977. We examined the slag fuming process with the purpose of achieving: 1) Improvement of the operating results by recovering zinc and lead from blast furnace slag. The lead content in slag at Chigirishima is slightly high, because the height of blast furnace shaft is low and consequently the quantity of sinter smelted per area at tuyere level is rather large. 2) Production of a salable slag as raw material for cement by lowering zinc and lead content in slag.

Jan 1, 1980

By A E. C Peres, J D. Donda

With the aim of producing a concentrate with silica content lower than 1.0 per cent SiO2, laboratory experiments were conducted using a sample of the final concentrate from the Samarco iron ore flotation plant (mechanical cells circuit). The sample contained 3.08 per cent SiO2. This sample was split in two size ranges: >105 ¦m and 2. The >105 ¦m fraction, representing 23.3 per cent of the initial mass, was re-ground to 100 per cent 2 content were obtained. Considering the mass proportions of the two size fractions, the calculated silica content of the combined concentrate was 0.68 per cent, which is considered satisfactory for the objective of this investigation. The major reasons for the higher (0.90 per cent) silica content of the concentrate from the coarse fraction are the presence of silicon in the lattice of goethite and the presence of residual silicious slimes in the pores of porous hematite.

Jan 1, 2005

The Beaconsfield Gold Mine within the township of Beaconsfield in northern Tasmania has been established in recent years to exploit a known resource in the Tasmania Reef which was mined to a depth of 450 m below surface between 1877 and 1914 yielding 850 000 ounces of gold. Activity at Beaconsfield over the past 30 years has involved drilling to assess the resource and rehabilitation of the top 100 m of the Hart Shaft that had collapsed since the original closure. More recently the mine has been dewatered to the 375 m Level and work is well advanced establishing infrastructure aimed at recommencing production during 1998 - 99. This paper reviews geotechnical studies undertaken to-date and provides a brief overview of some practical methods of analysing ground conditions. It pursues simple observation and analysis as a tool for assessing mine design and ground support options without recourse to extensive monitoring and measurement and avoids the use of elaborate models before the basics are understood.

Jan 1, 1997

By B J. Monaghan, R J. Longbottom, S Prabowo, D Del Puerto, B Maisuria, C W. Bumby

The use of hydrogen as a reducing agent can substantially reduce carbon dioxide (CO2) emissions from the ironmaking process. Iron ore fines can be reduced in a fluidised bed (FB) using hydrogen (H2) at high temperatures (>800°C), although several studies have reported the sticking of particles which causes the bed to defluidise, effectively shutting down the process. Here, we report results from the reduction of New Zealand (NZ) titanomagnetite (TTM) ironsands in a small-scale laboratory FB (100 g) at temperatures between 800–1000°C using H2 flow rates up to 5 standard L/min. No sticking phenomena are observed under any of these conditions, which is attributed to the formation of a stable titanium-bearing oxide layer on each particle’s exterior, preventing iron-iron contact at the particle surfaces. Pre-oxidised NZ TTM ironsands have also been studied and shown not to stick. Interestingly, at lower reaction temperatures the reduction kinetics for pre-oxidised ironsands is faster than for as-received ironsands. This increased kinetic rate can be attributed to the preoxidation stage inducing micro-fractures that create a void for the hydrogen to diffuse into the inner regions of the particle. In addition, oxidation of TTM appears to segregate the particle into two distinct phases, a high Aluminium-Magnesium (Al-Mg) phase and a high Titanium (Ti) phase. The findings are important as increasing the operating temperature of the FB reactor results in a faster reaction rate and higher gas utilisation, making the process more economically attractive. Furthermore, oxidation of NZ TTM ironsands results in a faster reduction rate at lower temperatures (800°C– 900°C) opening the opportunity to reduce the reaction temperature which might be beneficial in a final commercial-scale process.

Sep 18, 2023

By Roberts M. L

Long Shaft was initially developed using a rail haulage system on every working level comprising battery electric locomotives and granby trucks loaded by rail mounted rocker shovels. Production was commenced using conventional hand held cut and fill mining methods. In an effort to improve productivity and reduce operating costs a mechanised cut and fill stoping method evolved to suit the wider sections of the orebody. To further improve productivity and reduce costs the mechanised levels of the mine are progressively being redeveloped to enable the use of trackless diesel haulage equipment. An added benefit of trackless haulage equipment will be the ability to place development mullock into stopes as Fill.

Jan 1, 1988

The patterns of flow of reaction gases through the flash furnace at the Kalgoorlie Nickel Smelter were simulated in a 1:20 scale model using a flow of water. Particular features of the flow down the reaction shaft, through the settling chamber and into the uptake leading to the waste-heat boiler were examined. Inferences were made concerning the effects of the patterns of flow on the efficiency of the smelting reaction, on the entrainment of dust by the gas stream and on the erosion of the refractory lining of the furnace. In addition, the effects of geometrical modifications to the arrangement of the concentrate burners and to the profile of the settling chamber were explored by making these changes to the model and observing the resulting variations in the patterns of flow.

Jan 1, 1991

By D Fukuda, K Kaneko, R Kudo, J Kodama, Y Fujii, T Sasaki

"Estimation of stress state as well as elastic modulus is important for the prediction of a rock slope deformation in an open pit mine since it can strongly influence the mining-induced deformation of the rock slope. This study applies a method to evaluate regional stress state and Young’s modulus by analysing the mining-induced deformation of ground. The effect of changes in regional strain state due to tectonic plate motion can be accounted for using the proposed method. Mining-induced deformation can manifest itself as changes in ground surface geometry resulting from mining activity. There are three underlying factors that can contribute to the deformation: displacement induced by the effect of gravity displacement induced by the effect of horizontal regional strain incremental change in the horizontal regional strain. The relative displacement arising from the mining excavation at the Torigatayama limestone mine in Japan has been measured by Global Positioning System (GPS). Both the regional stress state and Young’s modulus were estimated by back analysis of the change in distance between GPS stations using a 3D finite element method. It was shown that the reliability of the estimation improved with an increase in displacement due to mining progression. It was also shown that values for Poisson’s ratios of less than 0.10 are reasonable estimates with values for Young’s modulus between about 5?GPa and 10 GPa. The magnitude and direction of the maximum compressive stress in the district surrounding the Torigatayama mine were estimated to be between -6.4 MPa and -4.4 MPa and around N25E respectively.CITATION:Kodama, J, Sasaki, T, Fukuda, D, Kaneko, K, Fujii, Y and Kudo, R, 2014. Estimation of regional stress state and Young’s Modulus of ground at Torigatayama Limestone Mine in Japan, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference, pp 135–142 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 5, 2014

During the lifetime of an open pit mining project, each stage from exploration activities to exploitation and mine closure produces disturbances on the mining region. Mined land reclamation plans establish constructive solutions to rehabilitate the disturbed areas. Open pit mining as an effective method for exploitation of a wide range of orebodies especially for massive reserves of shallow metallic substances has exhaustive and harmful environmental effects on the mining project region. Nowadays, closure and reclamation stage in a mining project is emphatically enforced by the relevant environmental protection regulations in many countries. It is therefore obvious that closure and reclamation costs of an open pit mining project, as costs of other stages of project, must be estimated to enter the planning and design processes in open pit mining. Post-mining land use is the most important factor to recognise closure and reclamation costs. Thus, using a model to define optimal land use in planning phase of an open pit mining project is necessary in this regard. In this project a model was developed to define optimal land use regarding different sections of open pit mines such as pit(s), waste dump(s), tailing pond(s), roads, areas for onsite facilities and free land zones which are not mined. TOPSIS and PROMETHE techniques were applied to create the developed model. Lumber production was recognised as the optimal post-mining land use for the pit area of the case study in this project.

Dec 6, 2010

By Gaulton R

The Commission maintains a data base first computerised in 1957 and containing information from over 18 000 boreholes located mainly in the Latrobe Valley area. Some of the borehole derived information dates from the turn of the century, although most of it has been collected as a result of Commission investigations conducted over the past 40 years. The Resource Data Base contains not only information gained directly from the drilling itself but includes the results of chemical and physical testing on many hundreds of thousands of samples retrieved from boreholes. Replacement value of the Resource Data Base has been estimated to be around $200 million, and it's integrity and accessibility is clearly of paramount importance, not only to existing mining and power generating functions but to the future evaluation and use of the vast brown coal Resource.

Jan 1, 1992

Gold mineralisation at the Macraes Gold Project is hosted in the Hyde-Macraes shear zone and can be traced for ~30 km along strike, although economic resources are confined to a seven kilometre section in the vicinity of the Macraes  township. The shear zone, which typically dips at a low angle (~20¦) to the NE, is bounded by an upper hanging wall shear and a lower footwall fault. Mineralisation occurs along the hangingwall of the shear zone as well as in low angle concordant shears and stockworks. Ore types include graphitic cataclasites with variable amounts of quartz veining, 'lode schists' and quartz-vein stockworks. Mine geology and grade control activities are designed to ensure accurate definition of ore and waste as well as the accurate prediction of ore grade. Grade control involves an integrated process of blast hole sampling, geological mapping and geostatistical modelling. Geological mapping is carried out post blasting by means of excavating trenches across are zones defined by assay data. Conditional Simulation is used to model raw assay data to define ore-waste contacts and estimate ore block grade, although, geologically defined contacts have precedence. Low angle ore zones impart a wedge shaped geometry to many ore blocks. These ore blocks are bounded by contacts that can be selectively mined to, thereby reducing misallocation of ore and minimising grade dilution.

Jan 1, 2001

By Gibbons S. L, Ritchie I. M, Murr D. M

Fundamental studies on the transformations of iron oxides have been carried out and related to the solution conditions in the Becher process. The results show that a number of iron oxide interconversion reactions occur in the aeration reactor with the products depending on the pH, temperature and oxidation potential of the aeration liquor. It is concluded that the lack of process control in the aeration reactor of the Becher process significantly hinders the ability to predict and produce high quality single phase iron oxides of a consistent colour.

Jan 1, 1990

Plant growth is likely to prove the most suitable and satisfactory material to stabilise and cover quarry faces and worked-out surface mining sites. The careful selection of plant species is of paramount importance to the success of any attempts to re- vegetate these sites. Various tech- niques are recommended and attention is drawn to different factors,which will adversely affect plant growth.

Jan 1, 1976

By M Wortley, R Morrison, T Rivett

The tracking of ore through process hold-ups such as stockpiles has been traditionally been difficult to achieve. The inability to pinpoint the exact source in the mine of material that is feeding a processing plant has led to inefficient mine-mill reconciliation processes. In addition, a lack of understanding of the behaviour of ore in process hold-ups such as bins and stockpiles often leads to poor predictions of plant performance and to poor reconciliation of this to the orebody.This paper reports on two short case studies. One case study addresses tracking ore from various parts of two mines to the concentrator. The other follows synthetic particles through the coarse ore stockpile. Both studies use radio-frequency identification (RFID) tracer technology. The paper concludes by discussing general strategies for implementation of such concepts into mine-mill metal accounting and reconciliation systems. As shown in this paper, reliable ore tracking systems will allow much more effective mine-mill reconciliations as well as the ability to model process hold-ups with regard to size by residence time distributions. This should, in turn, allow metallurgists to have a better understanding of the size and grade of material that will report to the plant at different process hold-up (eg stockpile) conditions.

Jan 1, 2009

By Struthers M. A

The basement contact zone, a major fault structure underlying the copper orebodies at Mount Isa, has a significant influence on orebody extraction. The zone is comprised of a variety of weak, barren lithologies which often create very difficult mining conditions, contribute to stope dilution, and have an adverse effect on concentrator recoveries.The geological characteristics of the contact zone are described, and the importance of timely, accurate geological information emphasized.A variety of mine design strategies have been employed to reduce the impact of the contact zone on orebody extraction. Some of these are discussed, together with current trends in the southern areas where orebody geometry and hence mining methods change markedly.Recent developments in ground support techniques, such as cable dowel reinforcement, have significantly improved ground conditions in the contact zone. An example of the methods employed to improve knowledge of ground behaviour is presented. The trend towards increasing automation and larger equipment requires larger excavations; consequently ground support practices and knowledge of ground behaviour must continue to advance. Rock mechanics investigations will remain an essential part of the mine design process.

Jan 1, 1990

By M Revell, B Sainsbury, D Sainsbury

This paper extends the existing knowledge associated with the design and placement of prefabricated pastefill barricades through a consideration of asymmetric drive geometry and conditions. The load capacity of prefabricated barricades and their failure modes are considered in relation to abutment geology and barricade geometry that includes curvature and span and drive geometry that includes abutment angles, haunch angles and misalignment. Design charts are provided for typical barricade sizes to provide general guidance for design capacities and optimising location placement based on asymmetric drive geometry. A recent barricade failure is considered in relation to the drive geometry and the potential impact it had on the installed capacity.

Nov 29, 2022

By P Vix

A thermodynamic model of the copper Peirce-Smith (P-S) converter has been developed to predict the behaviour of magnetite in the converter slag, the amounts of slag and matte, the compositions of slag and matte, the volume of the bath, the bath temperature and the SEMTECH OPC signals. The predictions of bath temperature, slag and matte compositions and magnetite content in the slag have been validated by the industrial data. The effects of fluxing strategy, returns and skim charges, oxygen enrichment and temperature on the magnetite formation in the slag have been predicted and discussed. Some industrial applications of this model have been presented.

Jan 1, 2005

By T Y. Dube

In this paper current net present value (NPV) based mine valuation techniques that take into account market and private risk are discussed and analysed. Potential pitfalls that arise from the application of a portfolio, market or commodity based risk metric to a mining project are identified. An alternative non-simulative framework for quantifying and factoring market and private risk in NPV calculations is proposed and then applied to a hypothetical case study in an attempt to overcome identified pitfalls. Mathematical proof that a static discounted cash flow (DCF) calculation can underestimate or overestimate mine NPV is presented, the conditions for each are outlined and the degree of underestimation defined.CITATION:Dube, T Y, 2012. How the use of market-based risk metrics can undervalue good mining projects and overvalue poor ones, in Proceedings Project Evaluation 2012 , pp 29-34 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 24, 2012