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By Lyon R. J P

The quartz-cassiterite-wolfram veins at the Aberfoyle Tin Mine, north-eastern Tasmania, form a sheeted zone about 200 ft. wide and 1,600 ft. long in slightly contact metamorphosed shales, slates and greywackes, and are associated with a cupola of aplitic granite whose top is about 1,050 ft. below the present surface. Economic mineralization persists from the surface down to a vertical depth of 1,050 ft. to 1,100 ft., dying away in the vicinity of the cupola. Down to the 9-level there is a progressive increase in wolfram content of the veins, and a decline in cassiterite content, with increasing depth.The veins are banded or zoned, with a seivedge of muscovite on the wall. Cassiterite, wolfram and sphalerite occur inside the selvedges, projecting into a core of quartz of varying width. Other sulphides form the central part of some narrow veins, or occur as clots in the quartz. The general sequence of deposition of the ore minerals was: (1) cassiterite, wolfram; (2) arsenopyrite, pyrite, molybdenite; (3) pyrrhotite (in part); (4) blende-group minerals-chalcopyrite, sphalerite, stannite, pyrrhotite (in part)-as solid solutions; (5) galena, tetrahedrite, matildite, native bismuth, scheelite; (6) marcasite and secondary pyrite, magnetite and hematite. The sequence of deposition of the gangue minerals was: (1) fluorine-bearing minerals-muscovite topaz, apatite, triplite, fluorite-more or less contemporaneous with the cassiterite and wolfram;' (2) quartz-contemporaneous with the earlier sulphides; (3) carbonates--contemporaneous with the later sulphides. The stages overlapped somewhat.The composition of the sphalerite and heat treatment experiments with the solid solutions indicate that the blende-group sulphides were deposited at about 6000 C., and cooled rapidly, so that unmixing of the solid solutions was arrested. This accords with the likelihood that the country rock temperature was not above 2000 C. Annealing experiments at between 3500 C. and 6000 C. led to further precipitation from solid solution at the lower temperatures, and to significant segregation by solid diffusion within, a week, indicating that both deposition and cooling of the ore were rapid processes-completed in a matter of days. Since the mineralizing solutions must have lost some heat during...

Jan 1, 1957

By D David

The majority of SAG and ball mill design methodologies are applied using a single design value for mill selection, such as the 80th percentile ball mill work index or SMC value. Inherent in the selection of this design value is a desire for the mill to accommodate unfavourable, but not absolute worst case, feed conditions. It has been observed in numerous “post-mortems” of unsuccessful designs and also in many optimisation studies, that the selection of the design value has been poor. Statistical analysis of testwork data sets shows that inherent variability in the data can, by itself, lead to design errors. Metallurgical testing is an attempt to measure the characteristics of millions of tonnes of ore using only a few kilograms of sample. In this paper some realistic but synthetic test work data sets are used to explore old and new methods of defining the design envelope and subsequently selecting a reliable point. The aim of the paper is to provide practitioners with tools that reveal the adequacy (or otherwise) of metallurgical test programs intended to support various levels of project design. It also provide guidance as to how it is possible to statistically justify a comparatively high design point in the absence of adequate test data.CITATION:David, D, 2015. Measuring and taking notice of orebody variability – an essential ingredient for reliable plant design, in Proceedings MetPlant 2015, pp 10–26 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

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 S Henderson, J V. Lawless

The worldwide association of low-sulfidation epithermal gold mineralisation, bimodal rhyolitic-basaltic volcanism and rifting is confirmed in New Zealand. In the currently productive Coromandel epithermal-gold province reported Ar-Ar dating of adularia from low sulfidation deposits falls into two groups at 6 and 7 Ma. Bimodal rhyolitic-basaltic volcanism has been reported to be K-Ar dated at 9 to 7 Ma and 6 to 5.5 Ma. Epithermal gold mineralisation in Northland is spatially associated with bimodal basaltic-rhyolitic volcanism, with rifting cogenetic with that in the CVZ. The Taupo Volcanic zone (TVZ) is sufficiently young that the presence of a segmented rift with recent bimodal rhyolitic-basaltic volcanism can be genetically associated with epithermal gold mineralisation, which occurs as both fossil occurrences and in active geothermal fields. This reinforces the known potential prospectiveness of the Coromandel area and increases that of Northland and the Taupo Volcanic Zone.

Jan 1, 2005

The small scale alluvial gold mining industry in Papua New Guinea (PNG) is c.irrently the only form of small scale mining carried out in this country. It already contributes significantly to the economy with current production estimated at 2 000-2 500kg per year. Until recently, small scale alluvial gold mining has been confined to simple panning and sluicing of high grade alluvial and colluvial deposits. Traditionally the small scale miner in PNG has only worked gravels with gold grades in excess of 500mg/m3. Grades of this order are required to justify the hard physical labour involved ~n hand operated small scale mining methods. .he introduction of higher throughput technologies such as trommels fed by hydraulic excavators has the effect of altering what constitutes an economically viable deposit. Mechanised techniques allow for the consideration of grades of almost half that level. The potential and opportunities for utilising this type of small scale mechanised mining in PNG are enormous with large areas of ground with gold grades running in excess of 250mg/m3 and often up to 2000mg/m3 throughout the country. An assessment of the current operating economics of this technology in the PNG context is the principal objective of this paper. Small to medium scale mechanised mining can potentially contribute significantly to the PNG economy particularly as it lies within the react-, of many PNG businessmen. Its potential is currently somewhat limited by a general lack of infrastructure and is also constrained by socio-political factors.

Jan 1, 1991

The paper outlines the development of a solvent extraction process for the recovery of scandium, yttrium, thorium, and heavy lanthanides from waste sulphate liquor at the Port Pirie uranium treatment plant. A summary is given of known solvents for these elements, including the recently developed alkyl-phosphoric acid esters which are applicable to sulphate solutions.A kerosene solution of di- (2'-ethylhexyl) phosphoric acid (EHPA) has been suggested by some workers as a suitable solvent for fractionation of the lanthanides. Experimental work with this solvent showed that it could be used for initial recovery of the above elements from low concentrations in the complex sulphate liquor. In particular, scandium could be recovered as a high grade product by extraction with 0·lM EHPA, followed by a purification strip with 9N sulphuric acid, and final stripping of scandium with sodium hydroxide solution.To enable alkaline stripping to be used successfully, the kerosene solution of the reagent was modified by the addition of a small proportion of nonanol. Experimental work included laboratory scale batch tests and small pilot scale continuous tests.A proposed extension of the process for the separate recovery of individual heavy lanthanides, yttrium, and thorium is described.INTRODUCTIONAt the Port Pirie uranium treatment plant of the South Australian Government, large volumes of "barren liquor", free from 'uranium, are at present run to waste. This "barren liquor" results from sulphuric acid leaching of Radium,Hill uranium concentrate, followed by separation of solid residues and removal of uranium from the clear solution by ion exchange. The mineral davidite, from which the uranium is derived, contains other potentially valuable components, notably vanadium, chromium, thorium, yttrium, scandium, and the lanthanides. These constituents are...

Jan 1, 1961

Development of New Comminution Testing Methodologies for Geometallurgical Mapping of Ore Hardness and Throughput The emerging discipline of 'geometallurgy' is becoming increasingly recognised as a discrete and high-value activity that reflects an ongoing trend towards more effective mine site integration and optimisation. Constrained sampling that reflects and defines inherent ore body variability is a key geometallurgical requirement. This requires use of larger numbers of low-cost physical testing which can be applied to small sample volumes suitable for defining natural variability. The AMIRA P843 'GeMIII' project (Geometallurgical Mapping and Mine Modelling) is a major industry-supported research initiative designed to develop new tools, methods and protocols to support geometallurgical integration. As part of this integrated research a new more rapid low-cost comminution test (GeM Comminution index) has been developed which can be employed as a front line tool for geometallurgical mapping purposes and predictive throughput modelling. The test has been designed to be inserted into routine assay sample preparation and is based on constrained jaw crushing protocols linked to analysis of resultant size distributions. Extensive validation and modelling has shown the GeM Comminution Index (Ci) is correlated with the Drop Weight index A*b and Bond Mill Work Index (BMWi). Large scale trials have been conducted within a commercial assay laboratory to demonstrate and optimise incorporation of the Ci test into routine sample preparation protocols. While Ci based estimates of A*b and BMWi are not as precise compared to larger volume more expensive test-work, the ability to undertake large numbers of tests typically in a systematic down-hole manner, provides a high level of data support through adjacency. A Ci based approach is highly suitable for variability mapping, domaining and selecting large composite samples for more precise testing. Within the context of the AMIRA P843 project this forms part of an integrated work flow designed to support geometallurgical integration. The development of a comminution test linked to routine assay sample preparation represents significant value adding to a process that in most cases is already going to be carried out. This paper introduces the Ci test concept and application to geometallurgical testing for throughput modelling

Sep 13, 2010

By Met B. E

During the operation of the Parkes process of desilverising, and in the earlier days of the continuous process, gold and silver were removed separately from softened lead bullion. Gold was removed in the Parkes process by a selective zincing, and -in the continuous process by treatment with zinc in a special de-golding kettle, in each case a crust being obtained carrying the gold and a small portion of the silver. Actually the process could have been more correctly termed a de-copperising process, on accountof the relatively large amount of this metal present, and its affinity for zinc, which caused it to enter the crusts produced.The crust was treated in reverberatory furnaces, where the bulk of the copper and zinc was removed in by-products, and the resulting "gold bullion" cupelled to give adore bullion containing approximately 2,000 ounces gold per ton.For the purpose of parting this dore, a small Balbach-Thum plant of 11 cells was used, and once each six months a short campaign was conducted on the accumulated metal.With the development of the process of de-copperising smelter bullion by means of sulphur, when a bullion averaging about .004% copper was constantly available for refining, the need for a separate de-golding process disappeared.The de-golding kettle of the Continuous Process...

Jan 1, 1937

By D Lichti

This paper presents recent advancements in the MillMapper software technology, developed and used for thickness gauging of liners of cylindrical grinding mills used for mineral comminution. MillMapper uses calibrated laser scanner data captured inside a mill to determine thickness at several million points on all liner surfaces with millimetre accuracy. The paper is structured as follows. First, a review of the technology and its numerous advantages over existing techniques and the value it adds to operations are presented. These are followed by discussion of recently-implemented innovations, including improved visualisation and inspection tools, automatic ball charge volume measurement and automatic mill liner volume/weight measurement. Results from its application at several sites in Australia are presented throughout.

Jan 1, 2007

By J J. J Chen, J C. Zhao

A water/air model was developed to simulate the refining of molten aluminium by the sparging of gas through an impeller. The optimal gas dispersion depends upon selecting the correct gas rate for a given impeller rotational velocity to prevent flooding or channelling. Correlations illustrating this flooding behaviour exist for standard impellers within standard tank geometries. However the validity of these correlations has not been substantiated for gas dispersion in high temperature molten metals with non-standard tank and impeller dimensions. Metal refining is most efficient when fine bubbles are generated and uniformly distributed within the treatment tank. The application of some measuring technique able to detect this distribution within a non transparent operating treatment tank would be invaluable, enabling the optimisation of gas flow and impeller speed.   A technique has been developed to measure the pressure fluctuation levels at specific points in the water model. Comparison of these pressure fluctuation data with photographic evidence obtained in the water model suggests that the flow regime in the metal treatment unit may be determined using this technique.

Jan 1, 1995

By D Craw, L Cox, R J. Norris

The Rise and Shine Shear Zone is a mineralised low-angle deformation zone traceable for at least 7 km through biotite zone schist of the Dunstan Range, central Otago. The zone is commonly believed to be similar to the actively mined Macraes deposit. The Rise and Shine Shear Zone occurs in the immediate footwall of the Thomsons Gorge Fault, a regional scale Cretaceous normal fault that juxtaposes chlorite zone schist against biotite zone schist. Most mineralised rocks are deformed and record a progression from early stages of semiductile deformation to more brittle cataclasis. Folds in mineralised rocks trend northwards. The mineralised schist is hydrothermally altered with variable silicification, sericitisation, chloritisation, replacement of titanite by rutile and carbonate alteration. Gold is associated with pyrite and arsenopyrite and occurs in both ductile and brittle microstructures. Sheared and mineralised schist is cut by north-striking fault zones which host mineralised quartz veins. Veins in the shear zone contain hydrothermal albite. Trace element analyses show enrichment in As, U, Th and rare earth elements. Many of the above features are similar to Macraes deposit, but there are important differences. In particular, the Macraes deposit is hosted in lower grade rocks and truncated beneath by a normal fault, Macraes has no U or Th enrichment, Macraes veins have no albite and folds at Macraes trend NW-W. Rise and Shine mineralised rocks have no Cr enrichment and no hydrothermal graphite.

Jan 1, 2005

Polyacrylamide flocculating agent has been used in the Leaching Division 'of the Risdon Works of the Electrolytic Zinc Company of Australasia Limited since October, 1960. The number of thickeners in the continuous thickening stage was thereby reduced from eight to three. There has been an increase of 25 per cent in throughput and a reduction of solids in thickener over-flow from 3-4 g/l. solids to 0·5 g Ir. solids. Reagent addition has been at the rate of 0·25 lb Separan NP10 per ton solids.Additionally there has been a gain of 3 per cent in current efficiency as the direct result of the addition of Separan NP10 to purified cadmium sulphate solution priOl; to electrolysis for cadmium metal. A smoother deposit has resulted and it has been possible to increase deposition time between strippings from 47 to 71 hr. However, there has been a slight increase in the lead content of the cadmium metal produced.The use of Separan NP10 to settle copper bearing residue in a batch process stage has resulted in a five-fold increase in settlement rate and a reduction in purification cycle time.INTRODUCTIONThe Electrolytic Zinc Company of Australasia Limited, Risdon, Tasmania, produces zinc by electrolysis of purified zinc sulphate solution, the raw material being zinc sulphide concentrate. In the Risdon process (Van Arsdale, 1953; J ohnstone, 1953; Ross, 1949) the compound zinc ferrite (ZnO.Fe203) is formed during the concentrate roasting stage. When the roasted material is leached in dilute sulphuric acid the zinc ferrite is not attacked, and it remains as part of the insoluble leach residue, of which it may form as much as two-thirds of the whole. The remainder is mainly unroasted zinc sulphide, unleached zinc oxide, lead sulphate, gypsum, silver compounds etc. The zinc in the residue may be 10 per cent of that in the original concentrate.Continuous thickeners are used to recover the valuable residue from the impure zinc sulphate solution and the...

Jan 1, 1963

By Mech B

This paper gives a general description of mining practice at The Zinc Corporation Ltd., Broken Hill, New South Wales.The basic mining methods are those which have been common in Broken Hill for many years and have been well described in previous Proceedings. The main object of this paper is to indicate developments which have occurred in recent years and to describe changes in layout, mining methods and equipment which are taking place at present.The following headings have been adopted: History Geology and general characteristics of the orebodies, Geology, The lead lode, The zinc lode, General characteristics, Ore reserves, General mining method, Exploration and diamond drilling, Shafts and shaft sinking, Main shaft, Old main shaft, Block 5 shaft, New upcast airway, Development, Level interval, Level layout, Driving and crosscutting, Winzing, Rising, and Stope preparation.

Jan 1, 1946

By J Hall, A Gallardo, M Strizek

Mineralogy and coproponents Sino Iron, International Minerals and Austeel are in the process of developing four world class magnetite iron ore mines with multiple open pits along a 25 km strike length of Brockman Iron Formation to the south of Cape Preston on the West Pilbara coast. The close proximity of the proposed pits raises some challenging project approvals and environmental management issues relating to the impacts of dewatering at individual projects and the cumulative impacts of progressive development on local and regional groundwater resources, which includes a large fresh water aquifer system in the Fortescue River alluvium.This paper presents an outline of the hydro-environmental impact assessment process adopted and the key result that the cumulative impacts of dewatering at all four projects on the local brackish groundwater system in the basement rocks is only marginally more than the impact of any one project on its own, and that the impact on the Fortescue River alluvium aquifer is negligible. The paper also presents an outline of the proposed integrated water management approach that will involve coordinated monitoring, ongoing impact assessment and management, and reporting programs for all projects.

Jan 1, 2009

The C.S.A. copper-lead-zinc mine, located 7 miles north of Cobar in central-western New South Wales, is the largest known mineral ocurrence in the Cobar mining field. The generally discordant orebodies occur within a strike width of 600 ft and an overall strike length of 1200 ft. They are enclosed by the steeply westdipping, west-facing sediments of the Cobar Group, and comprise lenticular steeply north-pitching and eastdipping zones of sulphide mineralization which range in composition from massive pyrite-sphalerite-pyrrhotitegalena to less massive pyrite-pyrrhotite-chalcopyrite varieties.The thinly bedded siltstones, shales, and greywackes enclosing the mineralization appear to have derived some of their constituents from volcanic sources. They have been metamorphosed to the greenschist facies of regional metamorphism. At least two stages of deformation and folding have occurred. The first stage folded the rocks on a south pitching fold axis into their present configuration, and superimposed a strong axial plane cleavage which subsequently guided the emplacement of the mineralization. The second stage of deformation is considered to have controlled the zonal distribution of the orebodies.

Jan 1, 1970

Possibilities for Flotation Acoustics Monitoring - A Review

Sep 13, 2010

Tougher physical mining and processing conditions as well as economic circumstances are causing many mining companies to re-evaluate the effectiveness of their mine planning. The recent wave of inexpensive computing power provides the engineer an opportunity to go beyond the simple one-off manual mine design and production schedule. The basis of a good mine plan is a good reserves model. Concepts of mine model development are explored. The only advanced computer methods that have found consistent success in optimising mine planning functions are economic pit limits determination and material scheduling. Three pit 'optimisation' methods are examined; the moving cone, the Lerchs-Grossman 3-D graph algorithm, and the new network flow algorithm. A comparison between the methods in terms of total profits generated and computer time involved are made. The results show that both algorithms produced a higher profitability than the simple moving cone, but at much higher execution times. However, the profit increase never exceeded much more than 1 % of the base moving cone case. Finally, a method for the development of long range material production schedules with forward waste planning is presented.

Jan 1, 1989

By Tellis D. A

An outline is given of the general position of earthsciences information in Australia, the background to development of the Australian Earth Sciences Information System (AESIS) and the role of the Australian Mineral Foundation in developing and co-ordinating the projeot in co-operation with the CSIRO, BMR, National Library of Australia, AGIA, and many companies.Details 'of the system, method and anticipated rate of input (especially of unpublished material at which the System particularly aims), mode of dissemination, and use of the data base are discussed. Information on theAustralian Thesaurus of Earth Sciences and Related Terms and brief details of some 30 earth sciences information collections in Australia is given.

Jan 1, 1977

Except for uranium search, conventional oil well logging techniques are relatively little-used in mining exploration. The main reasons for this are cost and an apparent lack of awareness of the potential use of the methods in the search for ore. However, relatively inexpensive portable units are currently available for performing the simpler electrical and radiometric logs in diamond drill holes.The emphasis in oil exploration logging programmes is largely on the estimation of porosity. In most mineral work, however, porosity is not very significant, and factors such as mineral conductivity and radioactivity assume an important role.The Bureau of Mineral Resources (BMR) during a programme to explore for uranium and associated base metals in the area east of Rum Jungle, N.T., carried out electrical and radiometric logging of diamond drill holes as a routine part of their investigations. Case histories are described in which the logs were used to aid in defining stratigraphic sequences and transgressive structures in base-metal prospects. Some surface geophysicalanomalies were explained by the logging: induced polarization and electromagnetic anomalies were related to black slate; and self-potential anomalies were related to oxidation of pyrite black slate, or apparent electrokineticeffects in the black slate. The logs provided an objective appraisal of the rock units penetrated and thereby helped to differentiate lithologies.Borehole logging, including newer techniques such as downhole analysis, could be done in geological and geophysical investigations in other areas for a relatively small cost with a considerable potential gain of information.

Jan 1, 1978

By G S. Lane, G D. Richmond, J Dioses

This paper discusses the methods used in the design of flotation plants, including benchscale batch and locked cycle tests and pilot plant trials. Two case studies are presented, one for the Cadia Hill Gold Mine and the other for the Hellyer copper, zinc and lead plant. These case studies present different problems with widely different target grind sizes, liberation characteristics and HellyerÆs sequential flotation circuit versus CadiaÆs æsimpleÆ copper/gold flotation circuit. They have a common theme in that pyrite forms the principal floatable concentrate diluent. Hellyer ore contains finely disseminated chalcopyrite, sphalerite, galena, and tetrahedrite. The flotation plant design was based on extensive benchscale testwork (including locked cycle tests) on drill core and many months of operation of a 30 tonne per hour æpilot plantÆ, using the old Cleveland Tin Mine process plant suitably modified for the duty. The Cadia concentrator was designed on an extensive benchscale variability testwork program, approximately a dozen locked cycle tests conducted on drill core and two weeks of continuous pilot plant trials on three separate samples obtained from an adit into the orebody. The orebody is a monzonite porphyry with disseminated chalcopyrite/bornite/pyrite of very low grade (0.17 per cent Cu, 0.73 g/t Au). Methods used to establish the appropriate flotation circuits for the treatment of the Hellyer and Cadia ores, as well as the interpretation of the testwork data, are discussed in this paper. Plant performance is reviewed in the context of predicted versus operational performance.

Jan 1, 2002