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By L Reynolds

The portable infrared mineral analyser (PIMA) was trialled to determine the extent and intensity of any hydrothermal alteration halo associated with gold mineralisation in the Hyde-Macraes Shear Zone (HMSZ) of the Otago Schist.   Twelve diamond drillholes through the HMSZ were analysed with the PIMA at a sample spacing of 1 m. The drillholes were selected on two traverses along the line of strike and down-dip of the mineralisation in and around Panel 2 of the Frasers underground development.   The study showed that the Hangingwall shear of the HMSZ has a more distinctive infrared signature in intersections with high grades. The Hangingwall shear in these drill holes is defined by a shift in the wavelength of the Al-OH absorption feature from ~2220 nm to <2210 nm. This shift is attributed to a change in the mineralogy from phengite to muscovite. Overprinting this trend in some of the drillholes is the presence of the 2210 nm Al-OH absorption feature, ascribed to kaolinite. Kaolinite also tends to be present in numerous other regions of the schist above the Hangingwall shear associated with steeply dipping faults and foliation parallel joints. In drill holes with low grades the Hangingwall shear does not exhibit any obvious infrared signature.   At the scale of study, the PIMA does not provide evidence for an alteration halo associated with hydrothermal mineralisation above the Hangingwall shear. Possible tectonic movement may have displaced any alteration halo that once existed, away from the zone of mineralisation. For this reason, PIMA apparently cannot be used for predicting the location of the Hangingwall shear during exploration drilling. However, the study did show that the PIMA could define the Hangingwall shear when the rocks were sufficiently altered and mineralised.

Jan 1, 2007

Although the effects of sea level changes on ore concentration processes are to some extent obvious with certain deposits, e.g. beach placer deposits, they have been largely overlooked with others such as Mississippi Valley type lead-zinc deposits. It is contended that sea level variations may have more profound effects on a wide range of deposits than has previously been appreciated. These deposits include not only placer'and residual deposits but also stratiform copper deposits, Mississippi Valley type deposits, stratiform manganese deposits and Minette type iron deposits. Sea levels in paralic basins profoundly affect the influx of 'detrital sediment, and this has to be suppressed to allow for the accumulation of thick rich deposits of coal evaporites, phosphate or metalliferous sediment. Emergence can be associated with oxidized waters, erosion, and,solution of soluble rocks. Submergence can reverse the Eh trend and can lead to preservation of ores. Both realms of surficial sedimentary environments and subsurface diagenetic environments can be affected by changes in water pressure, gas pressure (pC02), Eh, pH, and temperature as sea levels fluctuate. Even relatively small sea level changes may have profound effects. For example, there is some evidence to suggest that when the level dropped below 100 metres about 10,000 years ago, the Red Sea became isolated by the sill at Bab el Mandeb in the south, and evaporated away to leave a series of shallow lakes. The Red Sea is 1 to 2 km deep. It was at times such as this that the well-known copper-zinc mineralization developed in the Red Sea trough. Changes in sea level also affect the stability field of gas hydrates which can yield large volumes of gas leading to mass movements on the sea floor (Warnke, 1986).

Jan 1, 1987

Neutralisation, normally using lime, is the most widely used method for treating high flows of acid mine drainage (AMD). Lime costs can be very high however. If carbonate sources could be used to achieve pH values above six, costs could be greatly reduced. For example, use of locally quarried limestone at Mt Lyell could potentially reduce alkali costs from about $A 3.5 to $A 1 million/year. Methods for enhancing the effectiveness of limestone and magnesite for neutralising Mt Lyell and Savage River AMD respectively have been examined through a series of investigations. Small-scale testwork found that the maximum pH economically achievable with ground limestone was about five, due to slow dissolution rates and surface armouring. The problems of surface armouring were greatly reduced by the use of crushed limestone or magnesite at high pulp densities (75 per cent solids w/w), enabling pH values >6 to be achieved in a practical time frame. The use of particle sizes in the range 6 mm and finer also reduces costs by avoiding the need for grinding, and reduces the problems of solid-liquid separation and solid recycling that arise if large additions of ground carbonate are used. Pilot scale tests were carried out using tumbling drum reactors with limestone and Mt Lyell AMD and a pulsed-bed static reactor with magnesite and Savage River AMD. pH values averaging 6.2 and 6.4 were achieved with Mt Lyell and Savage River AMD respectively. Approximately 80 per cent of feed acidity was neutralised. A preliminary engineering design and cost estimate has been completed on the pulsed-bed reactor and shows that the concept is technically feasible and, if results are confirmed, economically attractive. Further pilot testing is planned.

Jan 1, 2002

The reduction of titanium tetrachloride to trichloride can be achieved by employing hydrogen and electric arcs. It is possible to produce melts containing up to 50% TiCk in the eutectic mixture of LiCl/KCl by striking a D.C. arc at the surface in the presence of hydrogen and TiCl. vapour. If the electrode IS made to just penetrate the surface of the salt mixture, a hot zone results from the' high resistance contact with both lower chlorides and sintered titanium may be produced. The sintered metal forms just below the melt surface while the trichloride forms at the gaslIiquid junction.The "hotspot cathode" appears to offer a solution to the problem of producing coherent deposits as the spong'e metal can 'be continuously withdrawn in a similar manner to the "calcium process".INTRODUCTIONConsiderable interest has been shown for some years in the possible development of a cheap electrolytic process for the extraction of titanium metal, since a method using simple materials and cheap electric power would materially reduce the cost of production. Even when cheap starting materials are used, however, there exist several general difficulties in the operation of plant which both limit the speed of production and increase the cost of the product. It happens that most of the techniques so far tried produce a powder as cathodic deposit, and when this is the case the following difficulties arise:1. The whole contents of the bath must be treated with solvent in order to extract the 'metal powder which may itself tend to oxidise, and thus become contaminated.2. Fine metal powders, which often contain residual entrained salts, are less easy to consolidate by arcmelting than metal sponge.

Jan 1, 1956

By E de N, B H. Usher, F D. I Hodgson

Due to the haphazard application of static tests in South Africa, several methods and interpretations have been followed. This has resulted in confusion amongst practitioners and regulators in the use and validity of these methods. Research was done over a two-year period to define standardised methods and interpretation of results. This included laboratory testing and continuous consultation with all interested parties throughout the country. The research yielded a modified ABA, based on several existing methods. The methodology includes AP determination using hydrogen peroxide, and an analysis of the supernatant by ICP. This has the advantage of not only registering reactive sulfur, but also provides the NAG pH, that enhances the interpretation and QC of the tests. Analysis of the supernatant provides an indication of heavy metal solubilisation, should acid conditions arise. One hundred and seventeen samples were compared to Leco S analyses and provided a good correlation. The Leco values were slightly elevated due to the reporting of total S as opposed to æreactive SÆ. The NP method deviates from the usual methodology, in that H2SO4 is used (to provide a field analogy) and the fact that a 24-hour stabilisation period is allowed before back-titration. The latter modification appears to prevent psuedo-buffering by transient phases. These methods have also been tested for repeatability and prove to be robust. A very simple macro-driven spreadsheet, æABACUSÆ, was also developed. This spreadsheet allows the entry of basic data and provides a detailed interpretation and graphical display of typical ABA data. In cases where drill holes are used, the Pennsylvanian approach of volume calculation can also be done with ABACUS. The results of the research have been distributed to interested parties in South Africa and it is hoped that these methods and their application will find widespread acceptance.

Jan 1, 2003

In this paper presented are the criteria used when assessing the harmfulness of shocks affecting the buildings. Those criteria are based on the value of speed or accelerations of building vibrations. Presented is the scale of harmfulness of vibrations of Langefors and Kihlstrom, Bureau of Mines, and SWD contained in the Polish Norm PN-85/B-02170. The parameters of the mining shocks measured by the Lubin coal mine station were compared with the parameters calculated as per the correlations (regression curves). The average acceleration calculated from the correlations for eight measurements is only two per cent higher than the actual one. But the average frequency of vibrations calculated from the correlations for eight measurements is as much as 2.22 times lower than the actual one. In order to analyse whether that takes place in the whole range of the energy of shocks compared were the results of calculations from the correlations for various magnitudes of shocks and various distances from their epicentre with the results of the measurements. From that it follows that only for the shocks of the highest energies the lowering of the frequency of vibrations by two times causes movement from the higher zone of harmfulness to the lower one (for example from the IV to III). In the one-family houses in Lubin there were the damages that are characteristic for not only for the III but also for the IV sphere of harmfulness as per the SWD scale. That should be explained via further research and maybe it would be feasible to draw out a new correlation to determine the frequencies only for high values of energy of shocks and determine the preciseness of the acceleration and frequency correlations used presently.

Jan 1, 2003

Acclaimed as one of the most remarkable orebodies anywhere on account of its length and richness, the Oroya Shoot occurs on the eastern side of the Kalgoorlie gold mining district close to the contact of a fine-grained with a coarse-grained greenstone, and in association with sediments. In the same stratigraphic position on the synclinal flanks of a large drag fold there are a number of other flat ore pipes, smaller, but almost as rich in tenor. Although differing in control structure they are believed to be related genetically as all show a characteristic development of a bright-green ore known locally as "green leader". Folding and bedding structures have played an important part in formation of the ore shoots.INTRODUCTIONThe Oroya Shoot is the biggest individual bonanza of Kalgoorlie's Golden Mile. It has been stoped almost continuously over a length of 4,300 ft., and about 2,000,000 oz. of gold have been won from it. Naturally pillars are not left in the best sections of such an orebody and the detailed geology of stoped out portions can only be inferred from examination of adjacent workings.No mention is made in the literature of the actual makeup of the orebody although a few structures are shown on some of the old cross sections. A diagrammatic cross section, Fig. 1, adapted from Stillwell (1929) illustrates the form of the Oroya Shoot.Gustafson (1937) drew attention to the role of folding, previously unrecognized, in Kalgoorlie geology, and indicated that the Oroya Shoot is associated with a minor drag fold on the east limb of the Brownhill Syncline, itself part of a larger left hand drag on the Central Anticline. The latter in turn appears to be part of a regional right hand fold system as shown by Campbell (1953).

Jan 1, 1959

By R J. Nicholson, J M. F Clout

As part of an overall strategy to make significant new technological advances for the sustainability of the mineral processing and related process industries CSIRO Minerals has developed a new dry separation device. It represents a technology breakthrough and has the potential to radically change the way in which dry particle size classification is achieved in the minerals industry. Conventional dry separation techniques have limited applications and often suffer from low productivity, high operating costs, low separation efficiency, the need for dust control and a lack of flexibility. In the absence of efficient dry techniques, wet processing is often used. The use of wet processing either requires the introduction of water into a separation process, which causes environmental concerns through the need for water supply and tailings dams or the use of æunfriendlyÆ chemicals for dense media separations that have considerable impact on handling and disposal. Wet processing also increases operating costs due to plant instability, materials handling, thickening, filtration and product drying. The new CSIRO technology exploits a combination of natural and applied forces to achieve specific particle motions that produce size separation. In doing so, many of the traditional shortcomings of dry separation have been overcome. The CSIRO Dry Particle Size Separator is ideally suited for dry size separation applications within the size range 1 mm to 30 ¦mfor moderate moisture levels (2 per cent), have low unit throughput, produce a fixed cut size and are therefore impractical where very high unit capacity and low operating costs are required. This paper presents a review of dry separation devices together with details of the new Dry Particle Size Separator and typical results for a number of materials, including iron ore and quarry dust.

Jan 1, 2002

The Jurassic Walloon Coal Measures crop out over much of the Moreton Basin and contain numerous thin, banded coal seams which have been mined at various locations since the 1870s. Historically most mining has been by underground methods. Increased exploration during the 1970s and 1980s has led to the delineation of significant open cut coal resources and to the development of the Oakleigh, Jeebropillly and Ebenezer open cut coal mines in the Rosewood-Walloon area. Over 2 170 million tonnes in-situ of shallow, high volatile bituminous coal with a mean maximum vitrinite reflectance of between 0.5 and 0.6 have been proven in the Basin.

Jan 1, 1991

CONTENTSSummaryIntroductionGeographical and Geological Outline of the RegionGrowth of the Mining IndustryTable 1: Production StatisticsGeneral GeologyRecent Alluvium and River GravelsSambeto SeriesMudstone and Basalt ContactVatukoula SeriesIntrusivesStructureGeologic HistoryLodesTable 2: Principal Lodes and Their OrebodiesMineral Assemblage and ParagenesisOre Shoots and Their ControlEmperor MineLoloma MineDolphin MineExplorationConclusionAcknowledgmentReferencesSUMMARYThe Tavua Goldfield was found in 1932 within a basin, both topographical and structural, near the sea on the north side of Viti Levu, Fiji, and has produced over £13,000,000 (Fijian) worth of gold and silver from the three mines...

Jan 1, 1953

By Sharma T

Laboratory investigations have been carried out on direct leaching of lead-zinc complex sulphide ore and zinc concentrate using ferric chloride. From the investigation it was observed that the use of 0.15 M and 2 M FeC13 gave an optimum dissolution of metal ions from ore and concentrate respectively. The kinetic studies conducted showed that the leaching reaction followed a shrinking core model for galena and sphalerite. The presence of impurities such as pyrite had increased the dissolution rate and reduced the consumption of ferric chloride. Further, the studies were conducted to recover dissolved zinc from the chloride solution by selectively precipitating it as zinc ammonium chloride.

Jan 1, 1992

This report on the 5th International Conference on Underground Space and Earth Sheltered Structures, which was held at the University of Technology, Delft, the Netherlands, on 2 to 5 August 1992, was submitted to the members of the Australian Underground Construction and Tunnelling Association. The report describes the conference themes and outcomes and puts forward some observations about a growing world-wide interest in the promotion of appropriate uses of underground space. The report recommends the creation of an Australian centre for research to bring together a wide range of professional disciplines and to focus attention on the potential benefits of using underground space.

Jan 1, 1993

The hydrological cycle in nature, with particular reference to Australia . 2. The definition of water pollution drawing on the experience of several major countries. 3. A description of the pollutants in water, and why they are pollutants. 4. The classification of waters as defined by major overseas countries. 5. The criteria and standards developed by major overseas countries for the classification of waters. 6. A brief- summary of the legislation adopted by overseas countries for the control of water pollution, and of the organisation and administration of controls. 7. A study of Australian legislation and administration of controls of water pollution. 8. General observations and conclusions.

Jan 1, 1971

While, in the past, a great deal of attention has been focussed on technical issues and the performance of explosives in rock, the explosive user, an essential link in the chain, has often been neglected. In the mining industry, too often, the benefits of excellent technical work have been degraded over time due to the lack of definitive and documented control. Using the principles of quality management a quality training system was developed and implemented for management of explosives use at Gunpowder Copper Ltd (GCL). This paper describes the structure of the system, its development and implementation, and contains practical advice and information for managers responsible for blasting and charge crews. The paper is in four parts: I Quality systems. A brief overview of the relevant aspects of total quality management that apply to explosives use. The requirements for documentation, management and auditing are explored. 2. Training for competency. The five essential elements of Competency Board Training (CBT) are examined, including auditing. 3. The Gunpowder Copper system. Implementation of the complete training system. Documentation and its control, auditing, instructions for operators, management responsibility and means of obtaining operator ownership are amongst the issues raised. Reporting requirements are the means to effectively manage change are described. 4. Summary. The paper concludes with the tangible benefits seen by Gunpowder Copper through the adoption of a quality training System.

Jan 1, 1995

Early in 1930 William S. Robinson, Managing Director of Zinc Corporation Ltd., anticipated a rise in the price of gold and a devaluation of the Australian currency. 'WS', as Robinson was known, formed a.syndicate in London, which later became incor- porated as Gold Mines of Australia Limited (GMA) to invest in gold mining properties in Australia. GMA examined many prospects and subsequently undertook the development of several mines in eastern Australia. The syndicate also held a number of options and several large reservations for gold exploration in Western Australia over which it was proposed to carry out an aerial survey and thorough scien- tific assessment. To do this Western Mining Corporation Limited (WMC) was incorporated in Melbourne on the 2nd March 1933. The founding chairman of WMC and GMA was the highly respected `Collins House' figure, Sir Colin Fraser. The aerial survey was carried out, and a group of eminent geol- ogists from Harvard University examined many prospects and identified several which warranted development. To finance these activities `WS' formed Gold Exploration and Finance Co. of Aus- tralia Ltd. (GEFCA), in London in July 1934. GEFCA ultimately held 95% of WMC and 62% of GMA. The finance came mostly from London based South African mining companies which had been subscribers to his earlier syndicate plus some American inves- tors. (The Group Structure in 1936 is shown in Appendix `B").

Jan 1, 1988

By Dixon D. R, Sparrow G. J

Pressure leach liquors from the pressure oxidation of a bulk flotation concentrate prepared from a complex Cu-Pb-Zn sulphide ore were treated to remove iron, either by pressure oxidation (the Hematite process) or with particles of magnetite (the Magnetite process), followed by cementation of various metals with zinc dust to obtain a purified solution from which zinc was electrowon. Satisfactory iron removal was achieved by both processes after neutralisation to pH 4.5 or 5.5. Pressure oxidation of the liquor at 200¦C and 690 kPa oxygen overpressure, conditions similar to those of the Hematite process used in the zinc industry, resulted in the precipitation of the iron as hematite. With the Magnetite process, an iron hydroxide was precipitated onto magnetite at atmospheric pressure and ambient temperature and removed by a magnetic separation step. The performances of both these processes for the removal of iron are compared. It is concluded that the Magnetite process offers considerable cost savings. Other impurities, in particular arsenic, were also removed with the iron in both processes. Cementation at pH 5.2 and 85-90 ¦C with 3.5 g/L zinc dust reduced the levels of copper, cadmium, and nickel to a satisfactory level and subsequent electrolysis in a laboratory cell gave an acceptable deposit of zinc.

Jan 1, 1989

A sequence of ultramafic units, very well exposed in Munro township in the Abitibi areal, of the Cahadian Shield, exhibit features which indicate that they are sub-aqueous extrusions. They occur within a sequence of tholeiitic pillow lavas, thin graphitic sediments. and large differentiated sills. The units range from a few metres to more than 250 m in length and less than 1 m to over 30 m in thickness. Over 60 individual units, occurring as flat pancakes on top of one another, make up a total exposed thickness of 150 m. The units have formed from a magma composed of a very olivine-rich picritic liquid carrying up,to 40 per cent olivine phenocrysts in suspension. Different units display a variety,of cross-sectional profiles. As an example of the most extreme type of profile, a typical unit 2 m thick consists of a cap of highly jointed fine-grained quenched rock, 10-30 cm thick, which becomes coarser downwards, grading into a zone composed of radiating and criss- crossing skeletal olivine crystals forming the well-known spinifex texture. This becomes even coarser-grained downwards, with "books" of parallel platey olivine crystals developing sub-perpendicular to the plane of the units. Beneath this zone, which may be up to 1 m thick, there is an abrupt transition to a cumulus-textured rock composed of rounded

Jan 1, 1973

Stressed steel cables, similar to those used in pre-stressed concrete, have been used for rock mass reinforcement, in civil engineering, for many years. This type of reinforcement has been attempted for open pit wall support, on several occasions, but has never gained wide acceptance as a practical approach because of high cost and complexity of installation in a mining environment. On the other hand, untensioned, fully grouted cable dowels (cable bolts) have gained wide acceptance for ground support in underground mining and it is perhaps surprising that this technique has not been used to a greater degree in open pit mining. The first systematic application of this technique in Australia was at the Mary Kathleen uranium mine in 1976, where it was spectacularly successful in maintaining steep stable walls in a jointed rock mass with unfavourably dipping structures. Cable bolting, and other techniques, are now being used to an increasing degree for wall support in both small and large open pits, for two basic applications: 1. stabilisation of potentially unstable sections of a wall, or 2. to allow steeper walls and reduce waste stripping volumes. In virtually every situation, wall rein- forcement has significant economic as well as technical advantages. The paper describes the development of the techniques, the mechanisms of wall support, the methods used, and discusses several case histories of its application to Australian open pit mines.

Jan 1, 1986

By S E. Box, J L. Mauk

The Middle Proterozoic metasedimentary rocks of the Belt Supergroup contain important metallic mineral deposits like the diagenetic sediment-hosted stratiform copper mineralization, including the Troy (Spar Lake) deposit and the epigenetic hydrothermal veins in the lower Belt and Ravalli Group in the Coeur d'Alene district. Magnetite (Fe3O4) is a common and widespread accessory mineral in these rocks and can have multiple origins including ore stage in deposits, mobilization stage in source rocks, metamorphism of red beds and alteration mineral in thin halos enveloping Ag-rich veins in the Coeur dÆAlene district. As shown in several classic studies, the composition of magnetite from igneous rocks varies significantly in response to controlling factors such as melt composition, temperature, silica activity, and oxygen and sulphur fugacity. Therefore, the distinctively different geologic settings within the Belt Supergroup strongly suggest that there may be differences in the magnetite compositions. However, initial microprobe analyses detected no variation in magnetite composition.   Three possibilities may give an adequate explanation for these initial results: 1.      the magnetite formed primarily as pure Fe3O4, 2.      one or more tectonothermal events led to regional scale re-equilibration that affected all rocks in the field area, and 3.      the variations in the composition are below the detection limit of the microprobe.

Jan 1, 2007

Dr Eric Bumstead is to be commended for his recent paper on gold analysis, published in the March 1984 Proceedings. It is not often that someone in industry, rather than academia, takes the time to collect and report on such a volume of data, data which is of interest to everyone involved in gold exploration and development.After reading the paper I felt, as a geochemist and as ayer, that there was another side to this whole question of analysis that few people are aware of, i.e. the problem facing a laboratory and how the laboratory can try to give the customer maximum value for money spent.Analyses for gold are carried out for different reasons, depending on the aims of the geologist or metallurgist who presents the samples. These can broadly be separated into three classes, to answer the following questions.1. "Is there any gold in this sample?"2. "Approximately how much gold is there in this sample?"3. "How much gold is there in this sample?"In every case there is a different balance between accuracy and precision, cost and avoiding chemical problems. By "chemical problems", I mean such possibilities as samples containing high levels of sulphides, gold present as tellurides, cyanide being present, contamination with mercury, and other mineralogical oddities, plus problems such as samples containing grease.There is no such thing as one assay to cover all possibilities.Samples in category I come mostly from early stages of exploration.There are often large numbers of samples, their mineralogy is not well known and hence chemical problems could exist, but the explorer wants assays at a minimum level of precision and expects minimum cost. These characteristics do not easily come together, for although the precision required is low, the accuracy required is high at low levels. A small positive result when the true answer is nil could lead to a fruitless search and a waste of money. Conversely, a nil result, when the true answer is a small but significant level of gold, could lead to the passing over of an area that may warrant further work.Because there are conflicting requirements for this type of assay, the methods chosen must be a compromise and different assayers will balance these requirements differently and come to different conclusions. The methods cover sample preparation, assay sample size and variations in assay techniques.

Jan 1, 1984