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By B Yang, L Wang, C Y. Ng

Flotation process intensification is often achieved through changing chemical reagent scheme or flotation machine or both, which likely brings a hefty burden to the flotation plants in terms of capital or operating expenditure. A novel approach to flotation process intensification is the use of acoustic sound, which has been demonstrated to be effective in improving the flotation of various mineral systems with different type of flotation cells. This approach was based on the dynamic stabilisation effect of acoustic sound on the flotation froth. The present work aims to understand the influence of various experimental conditions on the effectiveness of the approach. First, the effects of sound frequency and amplitude were studied with column flotation of silica particles. Results showed that the flotation performance was improved only within a certain range of frequencies and above certain amplitude. The study was then extended to the mechanical flotation of quartz particles with various size ranges and at two solids concentrations. With sound, the recoveries of different size fractions within the range of 20–212 μm were all increased. In particular, the recovery of 150–212 µm particles was increased from 0 per cent to approximately 25 per cent, demonstrating the potential for extending the upper limit of particle size in flotation by using acoustic sound. Furthermore, mechanical flotation of chalcopyrite particles at various collector dosages (50–150 g/t) was carried out with and without sound. Results showed that the increment of the final flotation recovery was increased with sound at different collector dosages. Overall, acoustic sound has the potential to be used as an effective and versatile method for flotation process intensification.

Aug 24, 2022

By Q Zhou, G Barrett, Y Choi, J Jiang

As part of a general review of processing double refractory ores through Barrick GoldÆs autoclaves /carbon-in-leach (CIL) facility at Goldstrike, a study was made to evaluate the use of surfactants for reducing the loss of gold during cyanide leaching of preg-robbing gold ores. Consistent improvement of gold recovery was observed with surfactants at various testing conditions. This paper will discuss the results obtained from laboratory and pilot-scale testing, as well as, review potential mechanisms for the observed improvement in gold recovery.CITATION:Zhou, Q, Barrett, G, Jiang, J and Choi, Y, 2013. Surfactants for gold recovery improvement with preg-robbing gold ores, in Proceedings World Gold 2013 , pp 367-372 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

The modern Golden Cross mine entered the production phase in January 1992. The project is designed to produce over 100 000 oz/yr of gold and over 300 000 oz/yr of silver during a mine life of eight years. An open pit and an underground mine are operated producing around 850 000 t/yr of ore, to feed a conventional carbon-in-leach processing plant. Golden Cross is owned in joint venture by Coeur Gold New Zealand Limited (80%) and Viking Mining Company Limited (20 %).   Since the start of production several major aspects of the design have altered. The underground mine began as a mechanised cut and fill operation. The cut and fill stoping progresses in 3.3 m flatback lifts with maximum stoping width of 6 m. Where the ore zone is wider than 6 m a post pillar cut and fill method is used. In 1993 a new bench mining plan was introduced between the 270 and 260 levels. Flatbacking continued in the footwall drives in anticipation of variability of the ore width and orientation. The development of levels below the main service 200 level has indicated a possibility of bulk mining the ore block rather than flatbacks. This could lower mining costs but also introduce higher dilution rates. Development is in the advanced stages for trialing this method.

Jan 1, 1994

By D Craw, C Smith, C Rufaut

Oceana Gold (NZ) LtdÆs, Macraes Gold Operation currently has two tailings impoundments, the larger of which covers approximately 75 ha. When an impoundment is temporarily out of use, the surface dries and dust can be blown from the surface to the surrounding area. At present water spraying is used to stabilise the surface, but this is not ideal as Macraes mine can experience water shortages during the summer. This paper examines an alternative method of surface stabilisation using vegetation as a ground cover. The tailings have a low natural fertility, so it is important to determine what will actually grow in the tailings, and whether amendments are necessary. Also important is the effect of the amendments on arsenic mobility in the tailings as the schist rock at Macraes has naturally elevated levels of arsenic. Three plants species, rye corn, barley, and lupin, were grown in metre-deep lysimeters at Macraes mine site. The plants were grown in unaltered tailings, and tailings with one of two amendments added: Bioboost (an organic fertiliser containing biosolids), and superphosphate fertiliser. The leachate from each lysimeter was collected and analysed monthly to determine the extent of arsenic mobility. In addition, laboratory experiments were set up to determine arsenic mobility in tailings with amendments at the centimetre scale.   All plants grew best with the fertiliser amendment, with rye corn growing the best overall. Plants growing in unaltered tailings either barely survived (rye corn, barley) or died (lupin). Plants in the Bioboost amended tailings grew only slightly better than in the unamended tailings. Laboratory experiments indicate that the addition of phosphate fertiliser greatly increases arsenic leaching at the centimetre scale when compared to unamended tailings. The addition of Bioboost only marginally increases arsenic leaching, compared to unamended tailings. This trend has not been repeated in the lysimeter trials on the metre scale over four months. Current results suggest that of the plant types trialed and amendments used, rye corn with superphosphate is the most practical short-term tailings stabilisation method at Macraes.

Jan 1, 2004

By Hargraves A. J, Smith J. W

Experiments conducted at Tahmoor Colliery, Sydney Basin, have demonstrated the variability in chemical and isotopic composition of seam gases issuing from boreholes in the Bulli seam and desorbing from lump coal from the same source.From this work it appears that an immediate preferential release of methane accompanies the physical disturbance of the coal seam by penetration with development or drilling or by detachment. In addition, both early released methane and carbon dioxide are depleted in 13C relative to later desorbed gases, therefore the analyses of gas samples taken after such events may not reflect the true bulk composition of the undisturbed seam gas in situ. A method for overcoming this problem by taking gas samples at depth in the "steady state" is proposed.

Jan 1, 1987

By A Batnasan

The main techniques for removing phosphorus as an impurity element in iron ores are physical separation (eg magnetic separation, flotation) and chemical separation (acid leaching, alkaline leaching and bioleaching) processes. When phosphorus occurs in iron ores as phosphate minerals (eg apatite), physical separation techniques are available to remove the gangue minerals from iron ores. On the other hand, chemical separation techniques are suitable for reducing phosphorus levels when phosphorus is associated with iron oxides and hydroxide minerals (eg hematite and goethite) in iron ores. In this study, the dephosphorisation behaviour of high‐phosphorus iron ore was investigated using a combined alkaline roasting and water washing route. Roasting experiments were conducted in a laboratory electric muffle furnace using various concentrations of sodium hydroxide (0–50 g/kg-ore) at different temperatures (100–800°C), varying prolonged roasting times (0–2 h), and different particle size fractions (-45 – -250 μm) of iron ore. Subsequent water washing experiments were employed at various pulp densities (30–1000 g/L) and different times (30 s – 60 min) at ambient temperature. Hematite and goethite were the main minerals in the high-phosphorus iron ore identified using X-ray diffraction (XRD) analysis. The iron ore assaying 63.40 mass % Fe (total), 0.240 mass % P, 4.53 mass % SiO2, and 4.87 mass % Al2O3 were determined using X-ray fluorescence (XRF) analysis. The results showed that the dephosphorisation rate of the iron ore was reached 40 per cent under roasting with 50 g/kg-ore NaOH at 300°C for 2 hours followed by water washing for 30 s with a pulp density of 300 g/L, reducing phosphorus level from 0.240 mass % to 0.142 mass %. At the same time, the iron grade was reduced from 63.4 per cent to 59.5 per cent, caused by an iron loss. Results suggest that the phase transformation of goethite induces the dephosphorisation of high-phosphorus iron ore under alkaline roasting conditions

Aug 22, 2022

Iron production in one year exceeds that of all other metals combined in ten years. It is a huge industry that started from a modest furnace producing one - two kilograms metal per day to a gigantic reactor producing 10 000 tons per day. The major milestones of these developments are reviewed.

Jan 1, 1999

By P Shen, K Hattori, H Pan, E Seitmuratova

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Ore-bearing intrusions in the Central Asian Orogenic Belt (CAOB) were examined from nine mines: Boshekul, Nurkazgan, Kounrad, Borly, Aktogai, Koksai, Baogutu, Tuwu and Erdenet. The intrusions are diorite, granodiorite and tonalite with SiO2 contents ranging from 58 to 75 wt per cent, and show mildly fractionated rare earth elements (REE) ([LREE]N/[HREE]N = 2.7–4.7) – light REE and heavy REE – and varying Eu anomalies ([Eu]/[Eu]* = 0.58–1.4). The ratios of Sr/Y vary from 7.9 to 115 and the contents of Y from 4.6 to 23.9 ppm. The parental magmas of the intrusions are intrinsically oxidised. Zircon grains in the ore-bearing rocks from large- and intermediate-sized porphyry Cu deposits show high Ce4+/Ce3+ ratios characterised by 65–422 at Boshekul (>4.1 Mt Cu), 76–480 at Kounrad (>4.8 Mt Cu), 90–280 at Aktogai (>12 Mt Cu), 80–250 at Erdenet (>11 Mt Cu) 74–370 at Nurkazgan (>3.9 Mt Cu), 100–210 at Koksai (>1.6 Mt Cu), and 71–340 at Tuwu (~2.0 Mt Cu). In two small deposits, the ore-bearing rocks display low values of Ce4+/Ce3+; Borly (0.6 Mt Cu) ranging from 28 to 158, and Baogutu (0.6 Mt Cu) from 29 to 113. The Ce4+/Ce3+ ratio of 120 distinguishes large intermediate-size deposits from small-size deposits. This information is potentially useful in exploration for porphyry Cu deposits in the belt.CITATION:Shen, P, Hattori, K, Pan, H, Jackson, S and Seitmuratova, E, 2015. Granitoids associated with porphyry Cu deposits in the Central Asian Orogenic Belt – characteristics and oxygen fugacity, in Proceedings PACRIM 2015 Congress, pp 377–382 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

Permitting, engineering and evaluation, detailed design and construction aspects of the Golden Cross goldmining project in New Zealand are briefly reviewed. The extremely lengthy and complicated governmental approval process together with the delaying tactics of opponents of the project are outlined and comment is made on aspects of the draft legislation proposed as part of the overhaul of New Zealand's resource management laws.

Jan 1, 1990

At Waiuta near Reefton there is a remarkable vein of quartz <1 m thick which, apart from small offsets on late-stage faults, is a sheet like body essentially continuous down-dip and along-strike for> 1 km. The vein strikes NNE and dips steeply west (032/78¦W). From 1906-1951 the Blackwater mine produced 740,404 ounces of gold from the vein, called the æBirthday ReefÆ, which was one third of the total production from Reefton Goldfield and the fourth largest gold mine in New Zealand. Within the mine the vein is disrupted into a series of northeast-plunging shoots by late-stage faults. Similar faults, but with larger displacements, were thought in the past to truncate the vein at the northern and southern ends of the mine. The implication of this fault dissection model is that offset remnants of the vein await discovery. This study investigated the geometry of the vein and its relationship to host-rock structures and late-stage faults. A new model considers folding and lithological variation in the host-rocks to be fundamental in controlling the scale and geometry of veining, but does not rule out the possibility of some late-stage fault dissection. The Birthday Reef truncates 200-400 m wavelength folds in Greenland Group host-rocks at c.10¦ angle, that results in variation in the structural properties of host-rocks along strike every ~1350-2500 m. The spacing of fold hinges in the wall-rock veins is equivalent to the strike length of historic mining, implying that the Birthday Reef is probably hosted in a single limb of a fold. Similar relationships between mineralisation and host-rock folds appear to be present elsewhere in the Reefton Goldfield (e.g. Capleston and Murray Creek group of mines). Exploration targets are located one fold wavelength (c.1350-2500 m) further along strike from the Blackwater mine and relatively barren rock is expected in between the mine and target areas. Refining the location of folds and different host rock lithologies, using geophysical data and quality geological mapping, is the key to reducing exploration risks and discovering further resources.

Jan 1, 2000

By R Ulusay

Rock mechanics involves characterizing the mechanical properties and behaviour of rock material and the natural discontinuities of the rock mass, while rock engineering is concerned with specific engineering circumstances, for example, how much load will the rock support and whether reinforcement is necessary. Rock engineering models developed depend considerably on the input data such as boundary conditions, the properties of rock material and rock mass. Correct evaluation of these properties frequently requires laboratory and in-situ tests, supplemented with a high degree of experience and judgment. Accordingly, since 1974, the ISRM Commission on Testing Methods has spent considerable effort in developing a succession of the ISRM Suggested Methods (SMs) for different aspects of rock mechanics and rock engineering with the contribution of a number of working groups and cooperation of some other ISRM Commissions. This paper emphasizes the need and importance of standardization of rock testing methods within the context of the ISRM SMs, gives a guideline for developing ISRM SMs and finally discusses on some implementation and contractual issues associated with rock testing and experienced in practice, and briefly introduces main future trends in rock characterization, testing and monitoring. This is an extended abstract only. CITATION:Ulusay, R, 2018. Standardisation on rock characterisation, testing and monitoring with emphasis on ISRM suggested methods, practical issues and difficulties, and future trends, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 17–18 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By S Hapugoda, A Edenton, M Adam, R J. Holmes, J R. Manuel, R Smyth

Lump ore is one of the key ferrous feeds used in the blast furnace ironmaking process, normally accounting for ten to 20 per cent of the blast furnace burden. Like other feeds, the characteristics of lump ore have an important impact on the stable operation and productivity of the blast furnace. Lump ore is usually assessed chemically, physically and mineralogically to establish its likely blast furnace performance. The physical characteristics of lump ore are strongly related to the chemistry, mineralogy and texture of the ore involved. In this paper, the blast furnace ironmaking process is reviewed, with particular emphasis on the key quality requirements for the ferrous burden material. A variety of key physical characteristics of lump ore measured using standard and non-standard methods are then described and subsequently correlated with the chemical and mineralogical characteristics of the ore wherever possible. Finally, the impact of these physical characteristics on blast furnace operation is assessed.

Jan 1, 2009

By F A. Roddick, C Swaminathan

As remaining gold deposits tend to become more refractory, some form of oxidative pre-treatment involving hydro or pyrometallurgy is necessary to maintain high metal recoveries. These pre-treatments include pressure oxidation, bio-leaching or roasting. In the past, the primary criterion for selection of oxidative pre-treatment relied mainly on the extent of gold recovery and relative economics. In this study, a different approach has been adopted, ie the quantitative determination of environmental performance of the oxidative pre-treatment processes bio-leaching, roasting and pressure oxidation to assess which had the least impact on the environment. By establishing the environmental performance of processes, waste minimisation can be addressed early in process selection. Using mass balances, the environmental theme method was applied to determine the performance, on the basis of gold treated, of the oxidative pre-treatment processes of selected plants. No clear trend was observed in the overall impacts of each of seven plants, with all but one of the environmental evaluation indices being of the same order of magnitude; this was probably due to masking effects arising from the large variations in feed composition, tonnage, and gold levels. Within each type of pre-oxidation plant however, certain trends were detectable. For instance, irrespective of plant size, ore composition or mineralogy, for the bio-leaching and pressure oxidation units, the general order of environmental impact from greatest to least was sequentially toxicity, acidification potential, depletion of resources, solid waste generation and greenhouse enhancement. For the roasters the acidification potential was the most significant. Determination of the environmental performance of the oxidative pre-treatment of a hypothetical ore in a plant of fixed tonnage was undertaken to remove the possible masking effects of variables associated with feeds of different mineralogy, gold tenor and tonnage. The bio-leaching process gave a marginally better performance than pressure oxidation, the roasting process the worst, although there was not a great difference between them. The decreasing order of contribution to the environmental index was acidification potential, toxicity, resource depletion, solid waste generation and greenhouse enhancement for bio-leaching and pressure oxidation; whereas it was acidification potential, solid waste generation, toxicity, resource depletion and greenhouse enhancement for roasting. Since the major contributor to the environmental index was the acidification potential, the environmental performance of treatment processes for the acidic effluents was calculated. After neutralisation of the net acid resulting from bio-oxidation and pressure oxidation, and the application of various scrubbing and product formation processes for the sulphur dioxide from the roasting process, it was shown that pressure oxidation gave a marginally better performance than bio-leaching, ahead of roasting. This study demonstrated the potential for the development of a predictive tool which could be used in determining the environmental performance, and thus the selection, optimisation, and improvement of pre-oxidation processes for least impact on the environment. These would allow operation of these processes within defined environmental performance limits and decisions regarding the desirability of processing various parts of a heterogeneous orebody to be made on environmental grounds.

Jan 1, 2000

Whilst the fossil fuel-based power industry moves towards carbon capture and storage (CCS) or so-called 'geosequestration', the minerals industry should adapt to reap the benefits of the new technology. If CCS becomes viable, the door is open to potential key developments in mineral processing. For example, truly continuous steelmaking could at last be realised using natural or manufactured gas combined with generic melt circulation. Iron ore fines would form a thin molten layer moving countercurrent to the gaseous reductant on one side of a melt circulation loop with efficient post-combustion without deleterious effects of slag accumulation on the other. This eliminates oxygen steelmaking because carbon has no access to the circulating molten iron. Steelmaking merely requires addition of the appropriate low level of carbon and in-line impurities removal to meet product specification. Concerning non-ferrous smelting, nothing short of virtually zero gas emission will be acceptable in the future. For dolomite-hosted Zn/Pb sulfide ores, typified by those in the Carpentaria region of Northern Australia, the way forward proposed is sulfur fixation at the mine site employing the highly exothermic reaction of SO2 with dolomite, followed by encapsulation of sulfated dolomite in fused ore slag. This releases enough energy for direct ore smelting to individual metal products. However, without CCS the strategy would be unacceptable because of greenhouse gas emissions. The scheme is advocated for direct ore smelting at McArthur River. As a result, the environmental problems of disposal of flotation tailings are avoided. Also, highly energy intensive ultra-fine grinding is eliminated, as indeed froth flotation itself, with overall very significant energy savings and exceptionally high increases in metals recovery. Zinc and lead recoveries approaching 99 per cent are predicted to be entirely feasible.

Sep 13, 2010

By J Player, P Evans, G Sweby

Achieving quick underground access after the completion of an open pit mine can be critical to maintaining project value and ensuring regular ore feed to the mill. This paper outlines the design and construction for two portals in an active open pit to commence underground development quickly whilst installing appropriate ground control to maintain long term access in an uncertain setting. Implementation of the portal designs was complicated by the change in underground design from hangingwall access to footwall access late in the life of the open pit due to preferable ground conditions. The portal locations did not have easy access for ground support installation integrated into the pit design due to the timing of the underground design changes. Practical implementation of the ground support systems subsequently became a key part of the project. Intact rock strength, rock mass characteristics, gradational weathering / alteration profile and structural information were modelled against pit displacement monitoring as the basis from which the portals were located and ground support schemes designed. Conditions around one of the portals necessitated numerical modelling to estimate the appropriate level of ground control for long term stability. The design was completed whilst the open pit was actively on-going and the portal areas not entirely exposed. The rock mass assessment and analysis for the two portals indicated different ground support scheme capacities would be required. The expected level of control for one of the portals also necessitated the use of monitoring with extensometers and load cells to ensure the rock mass response and ground support scheme performed as planned. Construction of the portals demonstrates the benefit of a considered design process, a plan which allows practical installation of ground support schemes where access is limited, the benefit of ongoing monitoring to ensure performance remains within design limits and the challenges involved working within an active pit with limited floor space.

Mar 15, 2021

By Greg Brown

The underwriting of professional negligence has proved to be an evolving science. As with most insurance products coverage offered in the past was very broad but as legal precedent demonstrated to Insurers areas of unforeseen exposure policy documents per se have become more restrictive until today the insurance market through attrition have produced a basic policy structure with various purchasable extensions which together provide insuring professionals with coverage that has proved to be adequate for their needs. The basic policy provides indemnity and protection for fortuitous negligence. In a practical sense, however, professional indemnity policies are really a defence document in so far as policy holders are relying upon the expertise of Insurers to protect them in the event that a claim is made upon them. Whether damages are awarded is in many respects a secondary consideration, the most important factor is to ensure that policy holders are protected in terms of the legal defence mechanism. By way of illustration we are currently in the process of defending a large professional firm which purchased from us a policy with a limit of indemnity of $10M. The case has been running in a Supreme Court now for 14 months and the defence costs which we have incurred on their behalf are rising close to $8M as I put pen to paper. Defence costs of that magnitude would in effect terminally cripple all but the very largest professional operations in Australia. In more recent times coverage has been provided in Australia for breaches of the Trade Practices Act and similar legislation enacted in various States. No-one really appreciated the comprehensive impact which the Trade Practices Act would have on commerce in Australia. Most professionals thought that indeed they would be exempt from prosecution under this Act. The passage of time has clearly indicated that this is not the case and we have found that it is much more difficult to defend a claim involving breaches of the Trade Practices Act than it would be to defend a claim for breach of tortuous liability.

Jan 1, 1995

Very few of those occupied in pursuits other than mining have any conception of the extent of boring operations that have been carried out on the gold and coal fields of Victoria, or of the valuable and definite knowledge obtainable by such means. The subject comprises various branches, which it will be necessary to describe in detail. The three main divisions are The Administrative, which includes all financial work and general management. The Professional, dealing with topographical and geological work necessary before any scheme of boring can be laid out, the preparation of plans, the inspection of cores obtained from bore holes, the examination of diamonds, etc. The Mechanical Branch, dealing with the drilling machinery, setting of diamonds, maintenance of stores, etc. In 1877, the Goverpment of Victoria decided to assist in prospecting the mineral resources of the colony by the aid of diamond drill boring, and for that purpose, a vote of £5,000 was passed, with which were purchased three diamond dulls, an American type being adopted.

Jan 1, 1901

Effect of Hydrophobicity and Frother Concentration on Bubble-Particle Interactions in Turbulent Flow

Sep 13, 2010

By A E. C Peres, P R. M Viana

The role of flotation columns in comparison with conventional mechanical flotation cells is discussed under the scenario of Brazilian flotation technology. All iron ore concentrator circuits commissioned since 1990 incorporated column only flotation technology in rougher, cleaner, scavenger configuration. Columns were also added to existing circuits, especially at the cleaner stage. Columns were also incorporated to phosphate ore flotation circuits operating mechanical cells. In two phosphate concentrators, columns substituted for all mechanical cells. Columns perform the cleaning stage in a large sulfide copper concentrator, following rougher flotation in tank cells. Scavenger of the cleaner tailings is performed in tank cells at this plant. Other ores that are concentrated in flotation columns include graphite, talc, lead-zinc sulfide, and a zinc hydrometallurgical residue for silver recovery.

Jan 1, 2005

By C Spandler, S W. Richards G Rosenbaum, R J. Holm

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.The recent and active magmatic arcs of eastern Papua New Guinea (PNG) and the Solomon Islands are well endowed with sulfide mineralisation and include deposits such as Ladolam, Panguna and Solwara 1. The majority of the mineral systems in this belt are younger than four million years old, with some deposits remaining active to the present day as exemplified by active hydrothermal systems on the island of Lihir. The geodynamic setting that led to the formation of these deposits is still unresolved, with, for example, both the Pacific and Solomon Sea plates considered responsible for the formation of the Ladolam deposit on the island of Lihir under different models. In order to understand and characterise the formation of south-west Pacific mineral deposits, we must first reconstruct the complex geodynamic evolution of the region. New kinematic reconstructions show that while mineral systems in eastern PNG and the Solomon Islands are hosted within a single arc related to subduction at the New Britain and San Cristobal trenches, variable and discrete geodynamic settings exist within both the upper and lower plates throughout this region, which give rise to distinct mineralised corridors. Most notably, this region is host to: the Solwara 1 deposit, which occurs within a major transtensional corridor in the eastern Bismarck Sea the Ladolam deposit (Lihir), which is interpreted to have formed above but in relation to tearing of the subducting slab the Panguna deposit, which is related to structure in the subducting slab marginal to the actively spreading Woodlark Basin.An evaluation of the nature and variability of these diverse geodynamic settings through time can provide us with a better understanding of the relationship between the active south-west Pacific magmatic arcs and mineral deposit formation. It may also provide insights into the diverse array of deposit settings at ancient convergent margins, with applications in mineral prospectivity studies.CITATION:Holm, R J, Richards, S W, Rosenbaum, G and Spandler, C, 2015. Disparate tectonic settings for mineralisation in an active arc, eastern Papua New Guinea and the Solomon Islands, in Proceedings PACRIM 2015 Congress, pp 165–170 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015