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By W A. Take, M McKellar, A Walsh, S McDougall, S G. Evans

Recent tailings dam failures have heightened public awareness of the hazard posed by storage facilities for mining waste, illustrating the need for a more critical examination of tailings dam breach mechanisms and the potential mobility of liquefied tailings. Knowledge from tailings dam breach studies will help improve safety and risk management through more accurate inundation maps, dam consequence classifications and emergency preparedness plans. Tailings dams differ from conventional water retaining dams, although dam breach relationships used in practice rely heavily on relationships derived for breach processes from the latter. Physical modelling offers a controlled environment to advance the understanding of tailings dam breach processes, thereby allowing for modelling of simple geometry and boundary conditions to test hypotheses. The performed experiments investigate prototypical tailings dam configurations and material behaviour, with the objective of validating numerical models that will enable practitioners to better assess and mitigate tailings flows resulting from tailings dam failures. Research conducted in the Queen’s University Landslide Flume at the Coastal Engineering Laboratory has investigated the breaching of 1 m high dams with tailings geometry by overtopping initiated by a v-notch incised in the dam crest. This paper presents the initial results of the next stage of this research comparing the outflow hydrograph following loss of containment caused by shear failure to overtopping initiated by notch flow. The two dam experiments presented are constructed with similar dam and reservoir geometries allowing for a direct comparison of the effect on the outflow hydrograph of each failure event. Preliminary outcomes suggest that although both dam failure events are triggered from separate mechanisms their geometries allow for similar values of Q_peak to be reached. Future work is currently planned to expand the shear test series to explore the influence of failure mechanism on the outflow hydrograph.

Jul 1, 2021

By M Nehring, M Kizil, P Knights, A Mousavi, F Sotoudeh

A cut-off grade is used to distinguish an economically viable block of ore from non-economical ones in mining operations. In order to obtain a high Net Present Value (NPV), a strategic and precise determination of cut-off grades (mill feed/marginal, marginal/waste) is required. In recent years, the significant depletion of feed grades and increasing mining operating costs have affected the viability of new and existing mining operations. Hence, the introduction of a pre-concentration system to process ore before sending it the main processing plant has gained increasing attention for its potential improvements in resource exploitation processes, mineral processing, energy consumption and environmental impacts. The primary potential advantage of implementing a pre-concentration system is the improvement of resource utilisation and increased reserves as a result of a reduction in cut-off grade. The objective of this paper is to present a new cut-off grade method, which can be used in the presence of a pre-concentration system for underground metalliferous mining operations. The results of this study illustrate the potential economic benefits of using a pre-concertation system prior to a mineral processing operation as a result of the reduced cut-off grade and increased NPV.

Nov 10, 2020

IN this paper an attempt is made to describe the sluicing operations on the tin fields of north-eastern Tasmania. No claim is made to completeness, for much of the ground has already been covered, and nothing is to be gained by needless repetition. On this account some portions of the subject have obviously received but scanty attention in order that others may be rather more fully dealt with; for instance, figures referring to the accuracy of various methods of valuing alluvial deposits, particulars of efficiencies, and water duties on both overburden and drift; also, the system of recording water distribution, &c.The plans of the tin-streaming shed, sluice and feed·race, and overburden tail-race represent types of the most modern design.The principal alluvial deposits being worked at the present time are situated either in the ancient or modern bed of the Ringarooma river or its tributaries. This river flowed in a north-easterly direction, receiving numerous tributaries on either bank, and finally emptying into Boobyalla harbour. The most important of these tributaries, from a mining point of view, are the Cascade, Main creek, Weld and Frome rivers (which unite just before joining the modern Ringarooma), Wyniford river, and Bradshaw's...

Jan 1, 1911

By P Hawke, J Hurst, B KrapeP

Hancock Prospecting Pty Ltd (HPPL) drilled two deep diamond stratigraphic holes (ECD0001 and RHD0296) within the eastern Fortescue Valley in the Pilbara of Western Australia. Located south of the Roy Hill Iron Ore project, the holes aimed to define the stratigraphy of the Marra Mamba Iron Formation (MMIF) of the Chichester Range and its south-dipping extensions below recent cover. Previous attempts to define the MMIF of the Chichester Range have resulted in differing interpretations due to the data available at the time.The unweathered MMIF beneath the Fortescue Valley in the HPPL drill holes is characterised by dolomitic carbonate interbedded with stilpnomelane-rich shales, chert and banded iron formation (BIF) with hematite staining. This intersection equates to ~75 m of carbonate-facies iron formation, as opposed to the ~230 m thick oxide-facies BIF and shale sequence encountered south of the Fortescue Valley.Various detailed geological core analyses and interpretations from ECD0001 and RHD0296 were integrated with regional diamond and reverse circulation (RC) holes from across the Fortescue Valley. Interpretation of the data indicates that the eastern Fortescue Valley MMIF represents a thinned thickness sequence of the whole formation. The MMIF of the Chichester Range and Fortescue Valley has gamma logs that correlate strongly in parts to the type section used for MMIF south of the Fortescue Valley. Therefore, the outcropping MMIF in the Chichester Range represents an eroded equivalent of the æreducedÆ thickness MMIF observed in ECD0001 and RHD0296.Data from deep diamond drill holes across the valley, from the Hamersley Basin to the Carawine Basin, were correlated. The correlation shows that the depositional site of the MMIF in the HPPL diamond drill holes is consistent with a proximal ramp setting, in which iron-rich shales wedge up-palaeoslope and shelf-derived carbonate turbidites wedge down-palaeoslope. Not only is it the occurrence of these shales that define the MMIF, but they also determine the northward potential to develop orebodies, as they are the source of iron from which iron-rich oxides and carbonates of metamorphic or diagenetic origin form.CITATION:Hurst, J, KrapeP, B and Hawke, P, 2013. Stratigraphy of the Marra Mamba iron formation within the Chichester Range and its implications for iron ore genesis at Roy Hill - evidence from deep diamond drill holes within the East Fortescue Valley, in Proceedings Iron Ore 2013 , pp 91-106 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By D H MACKENZIE

In common with several great orebodies and mineral camps around the world Broken Hill has been the subject of state-of-the-art technical and scientific scrutiny during its long working life. During the early years geological interest in Broken Hill tended to be directed at the body for its intrinsic scientific worth, mainly on account of its large size, high grade and wealth of mineral species. For much of the last 60 years the interest has had a more applied motivation, namely, to assist the search for either repetitions in the Broken Hill field or analogues in other terrains. This paper looks at the major changes in geological concepts and exploration techniques applied at Broken Hill and attempts to assess their impact.

Jan 1, 1992

GENTLEMEN, I have to thank you very much for the honour you have conferred upon me by electing me President of the Institute for this year. On behalf of resident members, I have to offer the visitors a very cordial welcome to Mount Morgan, and to tell them that all arrangements have been made to enable them to inspect the mine and works at their own convenience, and to supply them with any particulars they may need.It is very pleasing indeed to see such a large gathering, especially on account of the long journeys many have undertaken in order to be present. The first congress in Queensland, about eleven years ago, was attended by a comparatively small number of members, and a rather long time has been allowed to pass in consequence. The large attendance at this meeting encourages the holding of meetings in Queensland more frequently. Owing to the long distances, and the number of mining centres in Australia and New Zealand, we cannot expect to meet oftener than once in six or seven years in...

Jan 1, 1911

By S Wainio, P J. Beckett, T Miller

Lichens are a symbiosis of fungi and algae. Air borne elements and gases are absorbed very efficiently over the entire surface of the lichen, because they have no protective structures such as a waxy cuticle or stomata. A survey in 1977 (one year before the Sudbury Regreening program began), indicated that several Cladonia spp had invaded the soil in Sudbury’s open birch woodlands. Pollution sensitive species such as Cladonia rangiferina and C. mitis occurred 20–25 km from the smelters. It was anticipated that the improvements in air quality and reclamation efforts would allow a natural invasion of pollution sensitive species into what once was a lichen desert that surrounded the smelters. The purpose of this project was to study the invasion of terricolous (soil-inhabiting) communities of lichens and mosses on reclaimed land in the Sudbury region 45 years after commencement of the Sudbury Regreening Program.

Aug 2, 2023

By F Clark, J T. Carswell

Ore definition for final stope planning is often a challenging prospect in underground (UG) gold mines which exhibit high geological and grade variability. Unlike the grade control (GC) scenario in an open pit (OP), the ability for the mining geologist to plan a sampling campaign which effectively characterises the underlying mineralisation is fraught with difficulty. UG sampling patterns are strongly clustered and typically not dense enough to characterise the spatial and statistical properties. Very commonly, sample volumes are not large enough to provide a reliable grade estimate of the surrounding rock. These factors critically affect our ability to accurately map out ore positions and estimate metal quantities.At Sunrise Dam, traditional UG sampling and modelling techniques have proven to be an unreliable strategy for successful stope planning and extraction. The problem was first observed during the final cut-back in the open pit for which the mineral resource model was constructed from UG diamond drilling. Open Pit grade control reconciliations were strongly positive for both tonnage and grade compared to the resource model. Underground workings missed significant quantities of ore which was laterally defined by open pit reverse circulation (RC) GC drilling. Upon examination it was realised that the cause of the problem was one of inadequate sample density and sample support, the implications of which potentially affected the entire UG mine.As part of a broader study into underground grade control procedures, detailed reconciliation of initial stope production from the GQ domain also pointed to inadequate sampling as a major constraint to effective grade control and reserve conversion.To overcome this deficiency, dense 115 mm wet RC grade control drilling and conditional simulation modelling has been successfully implemented with the intent to replicate the grade control process in the open pit. The increase in sample density and sample volume has proven to be a very effective tool for mapping out highly complex mineralisation. A marked improvement in stope definition, reserve conversion and Mine to Mill reconciliations has been demonstrated on the back of an innovative approach to UG grade control.CITATION:Clark, F and Carswell, J T, 2014. Using reverse circulation drilling to improve sampling in a complex underground gold operation – an innovative approach to underground grade control at the Sunrise Dam Mine, Western Australia, in Proceedings Ninth International Mining Geology Conference 2014 , pp 143–152 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By M Sandy, P Bamford

The Challenger Gold deposit was discovered in 1995 by Dominion Mining Ltd in a remote western area of the Gawler Craton in South Australia. Mine development commenced in 2002 with initial production from an open pit supplemented by ore from a very small adjacent auxiliary pit. Development of the underground mine commenced in 2004. The orebody plunge of just less than 30 degrees requires careful attention to mine design. Production from the M1 orebody, with less than 800 ounces per vertical metre (ovm) and very limited æsurgeÆ capacity, requires careful scheduling and implementation to ensure continuity of ore feed for milling. Initial production results from underground stopes included more dilution than anticipated. The narrow, high-grade zones proved to have much more complex geometry than early interpretations had indicated. Greatly improved understanding of the mineralisation controls resulted in important changes being made to the underground mine design and method. Coupled with careful control of development and drilling and blasting practices, this resulted in an immediate reduction in dilution and high recoveries of the resource. The benefits of these changes flowed through in the 2005/06 financial year, resulting in a 150 per cent increase in gold production to 108 080 oz and a sharp reduction in cash operating costs to A$280/oz. This was followed in 2006/07 with production of 108 91 oz of gold at an operating cost of $309/oz and in 2007/08 with 109 326 oz of gold at $367/oz. Production to June 2008 has been mainly from the M1 orebody, with the lowest stoping to date on the 580 m Level (615 m below surface) above development mining on the 520 Level. The rate of vertical advance of mining this orebody has averaged 150 vertical metres per year. The increased current combined JORC compliant resource and reserve position of over one million ounces, now includes the M2 and M3 orebodies with a current total average gold inventory up to 1400 - 1500 ovm. Exploration has intersected other shoots and all shoots are open at depth. The adjacent M2 and M3 orebodies are being developed for stoping. The narrow width of these zones from 1 m up to 4 m will require continued focus on ore zone definition, accurate development and careful drill and blast practice. In addition, to minimise cost increases in the current period of rapidly escalating labour, equipment, consumables and energy costs, high productivities will need to be maintained to allow the established rapid mining advance to continue at low unit costs.

Jan 1, 2008

By N Setoudeh, A Nosrati, N J. Welham

The current surge of interest in lithium (Li) is due to the anticipated demand for electric vehicles and small scale power storage. Brine deposits contain most of the global Li resource, however hard rock deposits can be more readily and rapidly developed and comprise the majority of proposed projects. These projects plan to use the conventional processing routes of dense medium separation and / or flotation to produce a spodumene concentrate for sale. The standard route for subsequent processing of spodumene concentrate is thermal decrepitation, acid leaching, solution purification and precipitation of lithium carbonate. This is typically followed by further purification. A number of projects have ores which contain other lithium minerals, principally micas, lepidolite and zinnwaldite, necessitating an alternative treatment route. Several different routes for spodumene processing are under development to reduce costs to compete with brine projects. This paper will give an overview of the strengths and weaknesses of the current and alternative processes.CITATION:Welham, N J, Nosrati, A and Setoudeh, N, 2017. Lithium ore processing – an overview of the current and new processes, in Proceedings MetPlant 2017, pp 185–194 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By S Dorrington, J Olsen, N Kinkaid

Several studies have been conducted on the economic analysis of mining near-Earth asteroids for resources for use in Earth orbit. While these studies use detailed economic figures of merit, they often use many invalid assumptions in the trajectory design. Factors such as the energy and propellant requirements are estimated with analytic methods, however, the stay-time at the asteroid and the spacing of repeated launch opportunities are not taken into account. The work outlined in this paper attempts to combine detailed trajectory design methods with newly defined economic figures of merit to improve the economic assessment of asteroid mining missions. The study focuses on asteroid 2014 EK24, a near-Earth asteroid with very Earth-similar orbital properties.CITATION:Dorrington, S, Kinkaid, N and Olsen, J, 2015. Trajectory design and economic analysis of asteroid mining missions to asteroid 2014 EK24, in Proceedings Third International Future Mining Conference, pp 281–288 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

By I Y. Maslov, S A. Gorinov

It was demonstrated that the stable propagation of the explosive process is possible in low-density emulsion explosives (EEs) obtained through mixing of emulsion with a significant amount of expanded polystyrene (or other similar) granules. Such a process takes place in the form of a detonation-like wave of emulsion drops in explosive gas streams flowing out of the high-pressure area of the reaction zone.Chemical reaction in such EEs takes place in the form of surface combustion of emulsion particles interacting with the gas stream.A method was developed for determining parameters of decomposition of low-density EEs, and it was demonstrated that a gradual pressure increase takes place in products during the explosion of such EEs.The performed analytical research allowed low-density EEs (obtained through mixing of emulsion with a significant amount of expanded polystyrene) to be recommended for smooth blasting.Industrial-experimental blasts at quarries of Ural and Siberia, with extreme positioning of sides and using low-density EEs, have confirmed the viability of the recommendations given.The obtained results are useful in the advancement of smooth blasting technology using low-density EEs.CITATION:Gorinov, S A and Maslov, I Y, 2015. Physical and technical evaluation of possibility using low-density explosives in smooth blasting, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 555–564 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By T Davis

Cameco Corporation operates the high-grade 140 tpd fly-in/fly-out underground McArthur River Uranium Mine in Northern Saskatchewan in a joint venture with Cogema Resources Inc. Reserve grade is in excess of 20 per cent U3O8 with current mining grade averaging 16 per cent U3O8. Due to the high radiation potential of the ore, the non-entry mining method of raiseboring was chosen to minimise worker radiation exposure potential. The raisebore and extraction horizons are located in waste rock with the orebody located between horizons. Ore produced by raiseboring is delivered by LHD to an underground SAG mill and is then hydraulically hoisted to surface receiving facilities after underground thickening to 50 per cent solids by weight. Concrete backfilling is utilised. The orebodies at McArthur River are adjacent to water bearing sandstone. Ground freezing is therefore employed to isolate the ore from this water bearing ground. Calcium chloride brine at -35¦C is circulated through a series of cased boreholes to establish freeze walls up to 25 metres in thickness. At 18 000 000 lb of low cost U3O8 production per annum, McArthur River ranks as the worldsÆ largest uranium mine. Over 50 per cent of the workforce resides in this sparsely populated area of Canada with approximately 40 per cent being of aboriginal ancestry. Site operations must cater for winter temperatures as low as -50¦C.

Jan 1, 2002

By van der Walt TJ, van Deventer JSJ, Reuter MA

Owing to their complexity, many metallurgical processes are difficult to model fundamentally, and as a result more attention has been focused on the use of artificial intelligence techniques to simulate these processes. In this paper recent advances in the use of neural nets to model processes not amenable to conventional methods are discussed. These include the application of a new modelling methodology based on the use of neural nets for the dynamic simulation of metallurgical processes, the use of conventional techniques in conjunction with neural nets to simulate gravity separation circuits, as well as the detection of gross errors in variable measurements by means of a neural net representation of the relation between measurement and constraint residuals.

Jan 1, 1993

BHP-Utah Coal Limited operates 33 draglines of varying sizes in the Bowen Basin of Central Queensland. The group's operations with draglines commenced in 1963 with the establishment of opencut operations at the then TPM Moura Mine and continued through expansion of that mine, the commissioning of the Utah Development Company Blackwater Mine in 1968, and the subsequent establishment of six (6) other large opencut mines, all in the general area over the next fourteen years. These operations generally commenced with boxcuts on the sub-crop at depths of 15 to 25 metres. Over the years, depths have increased so that average depths now are in the 45 to 50m range. It was soon realised that dragline operations would have to be supplemented with additional stripping equipment. In 1981, a symposium "45m and Beyond" was held in Rockhampton to assess the problems associated with such "deep" stripping. Subsequently, dragline operations have continued and although addi- tional stripping capacity has been added, in many instances, draglines have been used and are being used to dig depths greater than 45m, some- times as much as 65 to 70m.

Jan 1, 1989

By H Ishikawa, S Palaniandy

The gravity-induced stirred mill such as the TowerMill is an energy-efficient grinding solution used in secondary, tertiary, and regrinding duties in the mineral processing concentrator. The interest in this technology is emerging, with more than 300 mills installed globally in various grinding duties and commodities for the last 30 years. Although the technology is matured, there are still opportunities for improvement and the development of new knowledge to improve its circuit energy efficiency and reduce water consumption. Recent studies show that a combination of stress intensity, ore hardness, slurry density, and mill feed configuration can be used to evaluate the performance of the grinding circuit. A recent pilot-scale TowerMill test work at various stress intensities shows that a lower operating work index and size-specific energy were achieved at higher agitator tip speed and using medium size grinding media. These outcomes were confirmed through several site trials. A smaller 17 mm grinding media has reduced the operating work index and size-specific energy by 18 per cent and 11 per cent, respectively, compared to the 20 mm in a magnetite concentrator. Moreover, the conversion from top feed to bottom feed configuration has reduced the operating work index and size-specific energy by 13 per cent and 37 per cent, respectively. The circulating load was reduced by 34–38 per cent, leading to a reduction in the dilution water consumption in the hydrocyclone feed sump by 20 per cent. A variable frequency drive offers flexibility to change the stress intensities on the TowerMill, where a 35 per cent reduction in specific energy was achieved when the ore became soft. This paper explores the potential design and operating strategies that can be implemented to enhance the energy efficiency, reduce water consumption and reduce CO2 emissions in the circuit and finally evaluate its impact on the total cost of ownership.

Aug 24, 2022

By S Gezgin, F Beckstein, M Müller, D Rapp, D Sergeev, J Qi, A Lichtinger

Salts and their mixtures play an important role for industrial and energy sectors, eg metallurgy, biomass gasification and combustion, nuclear and solar powerplants and electrochemical processes. Depending on the composition of salts (eg Li+, Na+, K+, Mg2+, Ca2+ // NO3-, F-, Cl-, CO32-, SO42-, etc), the temperature range for different applications can vary starting from room temperature and going up to 1500°C. For the proper design and modelling of heat exchangers and other equipment, it is necessary to have reliable and validated data sets of thermophysical properties. The 50 mol per cent NaNO3 – 50 mol per cent KNO3 salt mixture as a well-studied composition was selected for validation of relevant thermophysical properties (heat capacity, enthalpy of phase transitions, thermal expansion, viscosity and thermal conductivity). To study these properties of the liquid phase, special crucibles and approaches should be implemented. Verification of these crucibles for different methods (differential scanning calorimetry (DSC), thermomechanical analysis (TMA), laser flash analysis (LFA) and rheometers) has been performed. The low thermal conductivity of salts is one of the main problems in implementing latent heat storage. In this project, the authors intend to develop a fundamental solution to this problem using chemically bonded metals with salts. These are known as metal-salt solutions. To fit the main parameters of new phase change materials to the requirements of thermal energy storage, a wide variety of possible combinations should be considered. CALPHAD modelling is used together with thermal analysis for the development of a consistent thermodynamic database including chloride salts (Li, Na, K, Mg, Ca // Cl) and corresponding metals (Li, Na, K, Mg, Ca). The results of the study of quasibinary and multicomponent metal-salt (eg Mg-KCl and Ca-KCl) systems as well as the selection of suitable crucible materials and challenges by studying of these systems will be discussed.

Aug 21, 2024

By Nakahiro Y, Wakamatsu T

In the present study, from experimental results, a new concept of possibility of flotation separation of quartz from feldspar is presented. The effect of the nonionic surfactant Brij 58 on the flotation behaviour of quartz and feldspar has been investigated. The effect of the surfactant adsorption at the solid-liquid interface was also studied. The results demonstrate that maximum flotability of quartz occurred at low concentration of surfactant. Feldspar is not collected by this surfactant. Flotation tests with feldspar that had previously been subjected to leaching by hydrochloric acid yielded similar flotation response as that of quartz. The effect of removal of alkali cations from feldspar surface on its flotability was investigated. The effects of inorganic and organic additives on the flotation recovery of quartz are discussed in terms of the slating-out or salting-in properties of these additives. KEYWORDS: Alkyl polyoxyethylene; feldspar; flotation; nonionic surfactant; quartz; salting-in; salting-out; separation; silanol groups.

Jan 1, 1993

By Bidwell TJ, Servant S

Paste back-fill technology is gaining rapid acceptance in the Canadian mining industry. The authors were able to work on four different mining sites employing paste technology in their operation. In each site the paste hackfll is prepared with very fine tailings containing significant amounts of sulphur minerals. The research program involved laboratory testing on samples prepared in the laboratory, on control samples obtained at the hackfilll plant during pouring into the stopes and on core samples obtained from drilling in backfilled stopes. The laboratory testing provided detailed knowledge of the mechanical behavior of the paste backfill. The need for a means of measuring the in-situ mechanical properties of the backfill became clear. A review of various trials published in literature and an evaluation of available technology suggested the Cambridge Self-boring Pressuremeter. A first field campaign confirmed the efficiency and dependability of this instrument leading to the conclusion that it offers a very good method for the in-situ measurement of paste backfill properties.

Jan 1, 1998

By A Karrech, E Hamdi

The uncertainty of geomaterials properties is commonly encountered in resource engineering applications, especially in mining engineering where the rock mass texture, joints, fractures and damage zones can impose the mining method and operation cycles. In the present research work, we focus on the elastic properties of rock masses. We use stochastic numerical simulation of fractured rock masses to estimate their Young moduli. The procedure starts with field mapping campaigns which are conducted to evaluate the locations, dip angles, strike and trace lengths of pre-existing fractures. We develop statistical law parameters of the natural fracture network to represent the weakness patterns. In addition, we use HLA-Dissim, a recently developed and validated Matlab program, to simulate the propagation of monochromatic longitudinal waves and derive the equivalent elastic modulus of fractured rock masses. Such procedure applies within a simulation domain, which is greater than an Elementary Representative Volume.At a second stage, we conduct finite element simulations to validate the previous approach. The matrix and the actual fractures zones are reproduced in the model to mimic the natural set-up. The block is excited on particular positions and its response is evaluated on predefined spots. Real field rock fracture mapping data and monitored single-hole blast induced vibrations are used to validate the theoretical and numerical approaches discussed herein. Comparison between the simulated and measured vibration records shows a great agreement which confirms that the proposed methodology has a full potential to predict and optimise multihole/multidelay blast-induced vibrations.CITATION:Hamdi, E and Karrech, A, 2015. A methodology for rock mass characterisation to control blast-induced vibrations, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 89–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015