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By C. P. BATES

In November 1969, New Zealand Steel Ltd pioneered the commercial use of the SL/RN solid fuel direct reduction process to make sponge iron as a feed material for electric arc furnaces. Serious process problems with the use of green balls and coal injection were progressively overcome. The process was developed by New Zealand Steel along a radical route, of feeding the fine grained raw ironsand concentrate and coal directly to the kiln. Contemporaneously with this development of direct reduction, steelmaking process innovations were made that enabled the arc furnaces to operate successfully with the high volumes of acid slag.

Jan 1, 1980

By J Ralston, W Skinner, D Fornasiero

The Wark has been conducting collaborative research through the AMIRA International P260 series of projects for over 20 years. This paper reviews specific outcomes of successful technology transfer to flotation plant practice over that time. Moreover, findings of an independent audit of industry users of the research outcomes of the P260 project are reviewed. The key to successful technology transfer is the active engagement of industry personnel at all phases of the technology transfer process. Other research outcomes include the novel application of new measurement tools and methodologies which include, for example, advanced surface analysis techniques. These new tools and methodologies have been pivotal to improving our understanding of factors that limit the flotation separation of minerals at plant scale. Future potential targets for technology transfer to improve flotation plant practice are discussed.

Jan 1, 2009

Although the last decade has seen the growth of many new licencing and approval requirements for the exploration and mining industries, there remains in each State of Australia and the Northern Territory a predominant "Mining Act" containing provisions for the grant of exploration and mining tenements. What then are the rights and duties of tenement holders either by virtue of a Mining Act or through other approval and licencing mechanisms? What rights and duties does a person acquire when he is granted an exploration licence or a mining lease? In this paper I will attempt to cover these types of questions using in particular examples from New South Wales. I will also refer to a range of other subordinate approvals and licences which today's society requires and the need for ethics and recognition of liabilities.

Jan 1, 1995

Solid Energy New Zealand Limited (æSolid EnergyÆ) is a state-owned coal mining company, producing 4.0 Mtpa from a number of opencast and underground mines in the Huntly, West Coast and Southland regions in New Zealand. The company currently exports 2.1 Mtpa of coking coal. Exports are expected to grow strongly over the next five year as the company expands production into new semi-soft and thermal coal reserves. Domestic coal demand is also expected to grow strongly, particularly in the North Island, as the Maui gas field reserves diminish, and thermal coal becomes more important for electricity generation and meeting the energy needs of forest processing and other industries. Solid Energy is expanding and developing its risk management practices across all areas of the business: strategic planning û extensive use of scenario analysis and probabilistic modelling over a 20 year period; investment decisions û development and application of a rigorous six stage æProject Assessment GuidelineÆ process for all new mine developments; geological and geotechnical risk assessment techniques û use of best practice techniques including seismic surveys; financial risk management û a dynamic approach to hedging based on effects based analysis of Cash Flow at Risk analysis against preset risk tolerances; risk financing û the use of a captive insurance subsidiary, and the experiences of a small coal company seeking to obtain insurance cover on a æhardÆ international insurance market; and integrated risk management û the challenges of trying to implement a broad integrated risk management approach across the company, that supports implementation of strategic objectives as well as meeting æcompliance or legislative basedÆ risk management requirements.

Jan 1, 2003

Mining companies around the world are seeking methods to coordinate operations between the mine and the concentrator to achieve an overall improvement in enterprise performance. In several instances very significant increases in productivity (more than 20 per cent) and profitability (more than $US 10M per annum) have resulted from such efforts. The key to realising these large benefits has for the most part arisen from improved communication between mining operations and plant operations personnel and the judicious use of new tools to evaluate alternatives for improvement and to minimise the risk of implementation. This paper presents a systematic approach to mine-to-mill optimisation . The importance of systemic thinking and systems optimisation methodologies is emphasised. New tools for evaluating operational performance are discussed. Recently reported benefits are summarised. Finally current research is discussed and projections for the future are given.

Jan 1, 2000

By Miller M. J, Bauer J. C

The continuous copper drossing process operated at Port Pine since 1962 has had limited copper removal capacity as determined by a maximum tolerable Cu/S ratio in feed and the level of sulphur in blast furnace bullion. Recent process development has been to overcome these limitations to meet increased copper throughput requirements. A sulphur addition system was developed and installed in August 1987. The system has capacity to increase sulphur input by over 150%, meeting the increased copper capacity requirement and also allowing independence from the upstream process for sulphur supply. Developments in process understanding have been applied within the limitations of the existing furnace design with a 10% increase in the maximum tolerable Cu/S ratio.

Jan 1, 1989

By G D. Matthews, M E. Haylett, S Khosrowshahi, A Weeks

In narrow orebodies the use of ordinary kriging (OK) may pose certain limitations when used for grade control modelling. The smoothing effect of kriging, by its very nature, cannot retain or accurately characterise the dispersion (variability) that is inherent in gold deposits. This dispersion is a critical component of determining the desired level of ore loss and dilution.Fixed block model positions used in OK, and all estimation approaches, within a grade control process may never align with the ‘true’ ore boundary. This may lead to excessive ore loss and dilution, especially within narrow lodes.Using a risk-based approach to ore block design based on the geostatistical method of conditional simulation (CS) can highlight the differences achieved when an alternative method to OK is used for grade control modelling. By using a mesh of nodes and the application of a ‘transfer function’ to the simulation models, the position for ore contacts can be better assessed than when using fixed blocks in OK. Therefore, the value of various ore block boundaries can be better analysed by objective assessment of ore loss and dilution for a given minimum mining selectivity (selective mining unit or SMU), even in narrow lodes.A case study of a narrow vein gold deposit, comparing the results from an OK model and a CS model shows that whilst both models show similar trends – waste, low-grade, and high-grade regions are the same in both cases – the simulation model can provide greater insight for optimal definition of the mineralisation boundary.CITATION:Haylett, M E, Weeks, A, Matthews, G D and Khosrowshahi, S, 2014. Ore block design in narrow vein gold deposits – estimate or simulate?, in Proceedings Ninth International Mining Geology Conference 2014 , pp 421–424 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By A Harburg, A Dendys, G Green

Dugald River Mine (DRM) is located approximately 85 km north-east of Mount Isa, and 65 km northwest of Cloncurry, in the north-west Queensland Minerals Province of Australia. DRM is an underground operation and includes an above ground processing area, a 200 ha tailings facility, two waste rock dumps and associated infrastructure. The mining method is conventional underground longhole open stoping and downhole benching of a lead/zinc deposit within a black slate environment. The deposit is estimated to contain ~53 Mt of zinc and lead, which will be mined over a 30-year period. During operations, waste rock is segregated into either Potentially Acid Forming (PAF) or Non-Acid Forming (NAF) based primarily on the sulfide concentration of the rock. In particular, the NAF waste rock is an asset and is used for various small construction projects during operation; however, its primary use is for rehabilitation work at closure. Since beginning operations in 2017, DRM has generated more NAF than was originally anticipated. Whilst this is an excellent asset to DRM, it did pose a logistical problem of where to store the additional NAF for the life-of-mine and how to manage the run-off. DRM experiences distinct wet and dry seasons with hot conditions and periods of rainfall between November to April, and relatively dry and mild conditions between May to October. Majority of rainfall is received between January and February with an annual average rainfall of 501.1 mm. Short and intense rainfall events are common. DRM’s above ground infrastructure is land-locked between two large ephemeral watercourses, making the significant expansion of any assets challenging from a permitting/regulation and cost perspective. MMG is also a member of the International Council on Mining and Metals (ICMM) and is committed to adapting to a changing climate through operations and closure. Following extensive studies DRM opted to store the additional NAF material into the adjoining NAF Dam and concurrently upgrade a previously minor sediment basin into a highly engineered sediment basin which relies on automatic flocculant dosing to meet the required discharge quality limits. This basin is climate-resilient in that the dosing system can be adjusted to counter high intensity extended rainfall events which produce highly variable inflow water quality. This abstract broadly describes how DRM designed and implemented an engineering innovation to enable the site to meet the changing climatic challenges. The abstract then describes the process to design the sediment basin and how the dosing rate was established and validated. Finally, the abstract comments on the effectiveness of the sediment basin and how it has revolutionised DRM’s approach to water treatment and management; all whilst minimising the disturbance footprint of the operation

Aug 2, 2023

By Manlapig EV, Lawson F, Clarkson CJ

A low grade middling sample from Mount Isa, Australia, assaying 31.7 per cent zinc, 12.9 per cent lead and 14.5 per cent iron was leached under atmospheric pressure in sulphate and sulphate-chloride solutions with ferric ions as oxidants. About 96 per cent of the contained zinc was dissolved into a 0.5 M H2SO4 - 0.5 M Fe2(SO4)3 solution at 90¦C within three hours from a five per cent by weight slurry density mixture. The leaching process is very temperature-dependent, suggesting a surface chemical control. In the latter stage, the leaching rates levelled off and the leaching was most probably controlled by both surface chemical reaction and diffusion processes. The addition of chloride ions in the leach solution resulted in an increase in the leaching rate. About 95 per cent of the lead sulphide contained was converted to lead sulphate which precipitated and remained in the residue. Essentially no lead remained in solution and the low chloride concentration did not affect the precipitation of lead sulphate. Half of the iron orginally present remained in the residue as pyrite although essentially all the cadmium and 90 per cent of the copper initially present were dissolved. Some three per cent of sulphide sulphur was oxidised through to sulphate, about 67 per cent was converted to elemental sulphur which can be recovered by solvent extraction, the rest remained in the residue mainly as pyrite. Ferric sulphate and sulphate-chloride solutions can be used to effectively leach finely ground lead-zinc middlings and other bulk sulphide concentrates. A complete separation of zinc from lead and silver has been demonstrated.

Jan 1, 1993

A practical approach has been developed for the design of both grates and pulp lifters. It is based on: an appreciation of the process interaction between grates and pulp lifters, an interpretation of mill charge structure as it relates to discharge through grates, and an analysis of pulp and solids flow in pulp lifter channels. This approach can be used to improve the overall discharge effectiveness of AG and SAG mills.

Jan 1, 2000

Long-range side-scan sonar and conventional geophysical data for the Peru Trench region (8`S-15¦S latitude) have been analysed. The data show that the Peru Trench is a site of sediment subduction where bending-induced normal fault-ing of the Nazca plate plays a key role. The sediments are continually removed from the trench axis region by their inclusion in normal fault-defined void spaces, such as grabens. In the process of subduction, the sediments are often offscraped, folded arid kneaded temporarily at the base of the shoreward trench slope. The subduction complex comprising such sediments is narrower than 20 km and its volume remains more or less constant due to regular removal of its contents along with the down-going plate. Addi-tionally, morphology of the subducting Nazca plate is responsible for subduction erosion of the South American plate, where the horst blocks cause tectonic erosion by abrasion and the grabens provide a mechanism for removal of the eroded material.

Jan 1, 1990

By Khosrowshahi S

The objectives of grade control remain unchanged but new methods are being developed to attain them. Since the early-1990s, an improvement in the power of mine site computers has made the geostatistical tools of conditional simulation more accessible. Optimisation of the grade control process on mine sites now involves two stages: optimisation of the sampling regime and optimisation of the interpretation of ore and waste boundaries. Optimisation of the sampling regime first requires an understanding of the nature of the mineralisation and in particular the impact of particle size on the sampling precision. This relationship, termed the Fundamental Error of sampling, enables an optimum subsampling protocol to be defined for the sample preparation and assaying. However, the actual sample collection method, whether drilling or trenching, must be correctly selected and the sampling grid should be optimised. The relative costs and benefits of various alternative sampling methods and grids can be determined using the method discussed. The use of the grade control data can also be optimised. In the past ore and waste boundaries were often defined using a linear interpolation algorithm that smoothed the data (such as polygonal, sectional, inverse distance squared or even kriging methods). Frequently the relative impact of ore loss and dilution could not be estimated. Conditional simulation to generate equiprobable alternative maps (realisations) can now be adopted to address these issues. A transfer function is then used to evaluate the similarities and differences between the maps. The Ore Block Optimisation (OBO¬) process is a transfer function that produces a three-dimensional model of the optimal ore block outlines. This provides a clear guide for the mining geologist to refine and mine. The nature of the transfer function and the inputs and outputs are discussed. In the past, reconciliation has been the `acid test' for any grade control system. Any ore blocking method based on conditional simulation can make use of the exhaustive data set to ensure that reconciliation between prediction and production will improve significantly. The OBO¬ method provides a guide to the mining geologist to ensure that the best ore blocks are mined. Misclassification between ore and waste is reduced, ore loss and dilution are minimised (and are measurable) and ore is optimally assigned to stockpiles of various cut-off grades. These advantages significantly enhance mine profitability and control of the mined grade.

Jan 1, 1997

By F Sandrone, J-P Dudt, J Zhao, E Paltrinieri

Tunnel boring machines (TBMs) excavation is nowadays more and more considered a valuable alternative to conventional tunnelling. As a matter of fact, thanks to its advantages such as greater rate of advance and safer working conditions, the application of TBMs has increased significantly in recent years. Despite the possible excellent performance of TBMs in favourable ground conditions, the advance rates could be significantly slowed down or even obstructed in limiting geological situations. This obviously traduces in potentially longer tunnel construction times and higher costs and, therefore, in a preference for conventional method. One of the major geological hazards encountered during tunnel construction, is related to the presence of fault zones or heavily jointed and fractured rocks. The most common geotechnical problems resulting from tunnelling in these difficult conditions include the instability of the excavation face, instabilities of side-walls producing large overbreaks on the tunnel profile, excessive deformations in case of squeezing grounds, frequently changing stresses in terms of magnitude and direction, high water inflows, etc. The decisions aids for tunnelling (DAT) is a model and a computer code that can be used to evaluate the influence of the uncertainties related to both the geological/geotechnical conditions and the construction process on final tunnel construction time and costs. In this framework, the DAT is used for assessing the effects that challenging ground conditions may have on tunnelling operations in terms of costs and delays. This is done by simulating the tunnel construction considering several geological profiles. The aim of the study is comparing different excavation methods (ie drill and blast versus TBM) in changing ground conditions along the tunnel alignment ranging from good rock, to very poor and fractured formations. The results show the impact, in terms of changing construction time and cost, of the excavation method versus the ground conditions.CITATION:Paltrinieri, E, Dudt, J-P, Sandrone, F and Zhao, J, 2014. Comparison of excavation methods in different ground conditions with the decision aids for tunnelling, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 573–580 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By R Witt, M Lowing

Tanking of tunnels is now often specified when inflows exceed as little as 1 L/s/km with a unit distance of 100 m. To demonstrate inflows over a 100 m segment of a tunnel are less than 0.1 L/s with a standard error of 0.01 L/s by timed, gravity filled, volume measurement up and downstream of the segment, the measuring cylinder volume (L) must exceed 10 Q, where Q is the flow in L/s, and the number measurements taken and averaged must exceed 20 . If a standard error of 0.02 L/s is acceptable then 5Q2 measurements must be taken and averaged. If gravity filling is not possible then the number, n, of repeat pumped container measurement required is given by: where: is the 100 m section leakage is the volume filling time is the standard error of volume measurementZ is the standard normal variateK is a coefficient dependent on physical measurement conditions Based on analysis of field data an indicative coefficient of variation of volume measurement is ~0.05.

Jan 1, 2008

By Gang L

Seventy-nine gold deposits and prospects have been discoveried in the Jiamusi region of northeast China, and constitute one of the most important gold metallogenic belts in China. All these endogenic gold occurrences can be subdivided into three main deposit types: (1) porphyry related; (2) metamorphic-intrusive hosted, and (3) sediment-hosted deposit. The first two types of gold deposit are spatially and temporally related to Mesozoic Yanshanian granitoid intrusions with hydrothermal activity channelled along crustal-scale fissures. The ultimate cause of the Yanshanian magmatism is considered to be the subduction of Pacific oceanic lithosphere beneath the Eurasian continent. In contrast, The chemical sediment-hosted deposit is typified by the Dongfengshan gold deposit, and genetically related to Proterozoic sedimentation and Mesozoic igneous activities.

Jan 1, 1995

By M L, G Maddocks, A Ferrier, ers, A Forbes

Evolution’s Mount Rawdon Operation (MRO) produces gold and silver through open pit mining methods. The mining operations are scheduled to be completed in FY24 (Financial Year 2024), after which low-grade stockpiles will be processed until the end of FY27. As part of MRO’s Progressive Rehabilitation and Closure Plan (PRCP), RGS Environmental Consultants (RGS) and Deswik were engaged to develop the final landform surface and a whole of site probabilistic water balance/water quality (WB/WQ) model to evaluate the viability of several closure options with respect to water quality in the various site water storages, particularly the final void which will form a pit lake. This case study details the closure option which included (amongst other things) covering the final landforms and directing water toward or away from the final void post closure. Closure and rehabilitation for MRO had previously been planned and evaluated on a ‘domain’ basis. Furthermore, the rehabilitation plans and final water management plans for the Tailings Storage Facility (TSF), Waste Rock Storage Facility (WRSF) and other domains were not coordinated, possibly resulting in competitive rehabilitation material requirements at the commencement of closure activities. An assumption was that a legacy non-acid forming (NAF) stockpile would provide sufficient material to both supplement ex-pit material for the construction of the TSF embankment raises and to complete all closure activities, but the volumes available and the volumes required to complete the closure activities had not been quantified.

Aug 2, 2023

By K Tanguturi, B Belle, R Balusu

Management of high rates of goaf gas emissions between 4000 and 6000 L/s of methane gas in longwall panels is a challenging issue, particularly in start-up areas of the panels. There is a need for investigation of the effect of various goaf gas drainage concepts and techniques, and development of effective gas drainage strategies for management of high goaf gas emissions in start-up areas of the longwall panels. This paper presents the results of various computational fluid dynamics (CFD) simulations that were carried out to investigate the effect of different goaf gas drainage strategies and combinations for gas management in the start-up area of the longwall panels. Results indicated that the gas (methane) concentration in goaf holes on the tailgate (TG) side vary between 50 and 75 per cent under the simulated field conditions with flat coal seam gradients. The results also indicated that operation of more goaf holes for draining the goaf gas on the TG side results in high ingress of oxygen and further reduction in gas concentration in goaf gas drainage holes. The simulations also included scenarios with goaf gas drainage holes on the maingate (MG) side, TG cut-through seal and near the start-up area. This paper presents the results of various goaf gas drainage strategies and discusses the effect of various combinations in order to develop effective goaf gas drainage strategies for gas management in start-up areas of the longwall panels.CITATION:Tanguturi, K, Balusu, R and Belle, B, 2015. Development of goaf gas drainage strategies for start-up areas of highly gassy longwall panels, in Proceedings The Australian Mine Ventilation Conference, pp 251–258 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By A L. Stewart, M Baatar

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.The Middle Palaeozoic Gurvansaikhan Belt (Southern Mongolia) of the Central Asian Orogenic Belt is one of Central Asia’s most significant emerging porphyry copper provinces. The belt has become the focus of extensive exploration for porphyry copper-gold deposits over the last decade following the discovery of the giant Oyu Tolgoi porphyry copper-gold deposit. The Gurvansaikhan Belt is known to host porphyry deposits of Late Devonian (~370 Ma) and Early Carboniferous (~320 Ma) age. The characteristics of Early Carboniferous porphyry systems are poorly known compared to their older counterparts, despite their probable abundance and potential economic significance. Exploration within the Kharmagtai porphyry breccia complex has identified multiple cogenetic gold-copper-porphyry centres and late-stage mineralised magmatic-hydrothermal tourmaline breccias emplacement within a composite high-K calc-alkaline quartz monzodiorite intrusive complex. Early porphyry alteration and mineralisation at Kharmagtai are zoned around vertically attenuated early- and inter-mineral quartz monzodiorite dykes and stocks and comprises a complex sequence of calc-potassic, potassic and propylitic assemblages. Hematite dusting is a common alteration product that gives intrusions and the host rocks a distinctive pink-orange colour. Several of the systems have bornite-rich cores, where mineralisation is characterised by high gold grades (0.7 to >5 g/t Au) that zone outward to chalcopyrite-rich and then outer pyritic halos. Early stockwork mineralisation is overprinted by magmatic-hydrothermal tourmaline breccias. High-grade magmatic-hydrothermal tourmaline breccias form part of a major copper-gold mineralised breccia system with significant exploration potential. The Early Carboniferous porphyry copper-gold systems of the Gurvansaikhan Belt represent a substantial exploration challenge in an area of increasing exploration maturity. This paper summarises the characteristics of the Kharmagtai porphyry system that have helped to define the Early Carboniferous porphyry province of the Gurvansaikhan Belt and discusses implications for future exploration.CITATION:Stewart, A L and Baatar, M, 2015. The Kharmagtai porphyry breccia complex – characteristics of early Carboniferous porphyry mineralisation in the Gurvansaikhan Belt, Southern Mongolia, in Proceedings PACRIM 2015 Congress, pp 383–388 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

The purpose of this work is to determine the equilibrium-state of the aqueous-solution which is produced by the leaching processes, including natural weathering of pyrite minerals. The latter can lead to acid-mine-drainage (AMD). The ferric iron species (Fe3+) resulting from bacteria-catalysed oxidation of ferrous iron (Fe2+), in the presence of water and air, is known to bring about steady-dissolution of minerals chalcopyrite (CuFeS2), sphalerite (ZnS), pyrite (FeS2), and so forth. Good-aeration, relatively high-porosity and sufficient bacterial activity tend to promote leaching in waste-rock-dumps. The composition of the aqueous-phase that accumulates in the pore-space (or in open-pits) is of practical interest as it would strongly influence the leaching of both sulfide and non-sulfide minerals. Since the reactions among the various ionic species occur relatively fast, the solution-phase may be regarded as approaching a state of virtual-equilibrium and it is possible to determine by computation the respective concentrations of the many dissolved species. For the Cu-Fe-H-O-S system, these species may include: H+, Fe2+, Fe3+, Cu2+, HSO4-, SO42-, OH-, CuSO4o, H2O, Fe(OH)+, Fe(OH)2+, Fe(OH)2+, Fe2(OH)24+, Fe(SO4)+, Fe(HSO4)+, Fe(HSO4)2+, and Fe(SO4)2-. The aqueous-system which may be constituted from appropriate mole-quantities of H2SO4, FeSO4, Fe2(SO4)3, and CuSO4 is in fact the result of various natural processes (reactions) and due respect must be accorded to the extents of these reactions. The present model computes the equilibrium molalities of the foregoing ionic and neutral aqueous species, using the iterative equilibrium constant method that ensures strict-adherence to charge-balance and elemental molar-balance constraints. The dissolving sulfide-minerals (FeS2, CuFeS2) consume Fe2(SO4)3, H2O, and O2 and yield FeSO4, H2SO4, and CuSO4 while the aqueous-phase tends to become progressively acidic (declining pH) reflecting the gradual increase in the extents of sulfide-dissolution reactions. The equilibrium-state of the solution-phase is computed for specific set of values for the extents of respective reactions. The temperature and pressure of the system are 25¦ C (298.15 K) and 101.325 kPa (1.0 atm), respectively. The mica-like minerals such as the biotite [H2K(Mg,Fe)3Al(SiO4)3] tend to consume much of the H2SO4(aq), with the extracted K+, Mg2+, Fe2+ and Al3+ ionic species accumulating in the solution. The precipitation of the jarosites (potassium, hydronium, or ammonium) contributes to the removal of ferric and ferrous species from the solution-phase. In the present work, the emphasis is on predicting the compositions of the aqueous- and condensed-phases with advancing time or increasing æextent of reactionÆ. The results of such calculations are compared to published data on raw AMD (acid-mine-drainage).

Jan 1, 2008

By Rautio V

The mining sector has been automated and robotised very rapidly during the last few decades. The organisation of work, schedules and housing has been modernised from the traditional modes of industrial society toward the more flexible modes of

Jan 1, 1998