Search Documents

A comparatively new and very promIsmg field for applying cemented tungsten-carbides is in the mining and quarrying industries. The economic advantages of this unique engineering material over the conventional hollow drill steel, or steel detachable bits, have proven so great that the use of "hard metals" promises, in some instances, to revolutionise the drilling of all manner of minerals. Early in the war years the Germans realised the tremendous advantages cemented carbides offered for holing hard rocks, and they proceeded to develop detachable percussion bits to do this work, at the same time evolving fast, comparatively light-hitting driliing machines, especially designed to suit the mechanical properties of the carbide.Here in Australia also, it has appeared that the detachable percussion bit offers the greatest economic benefits to consumers, although the author is well aware that carbide-tipped drill rods have, and may continue to work out satisfactorily in certain mines and quarries.Most drilling equipment at present installed in Australia may be described as being of the heavy hard-hitting variety, so that the designer of an efficient percussion bit has to take special precautions to overcome the problem of fatigue, and to ensure that the inserts are securely mounted in the body with the minimum of internal stress in the carbide.

Jan 1, 1950

Knowledge of true block grades is obtained from a mathematical model of an orebody, simulated with sample grades normally distributed and spatially correlated according io a spherical semi-variogram model.The superiority of kriging to the polygonal method of estimation is demonstrated on this modelled deposit by comparing the true values with the kriged and polygonal estimates obtained from sampling the deposit. Finally, selection of blocks of the deposit on the basis of the estimated values, shows that if kriging is used, what is predicted is largely mined, whilst if the polygonal method is used large biases can occur depending on the position of the cut-off grade.

Jan 1, 1978

By Edwards A. B

The occurrence of lollingite (FeAs2 ) in the Broken Hill lode is recorded by an analysis of lollingite published in the Annual Report of the Department of Mines, New South Wales, for the year 1934 (p. 69). The analysed specimen came from the North Broken Hill mine, and material from the same occurrence (Specimeh No. 1), as well as two specimens (Nos. 3 and 4) from the Zinc Corporation mine, have been forwarded· to us by Mr. M. Mawby of the Zinc Corporation Mine. This material has been supplemented by another specimen (No. 2) from the Zinc Corporation mine, passed over to us by Dr. I. Wark.The original analysis of lollingite is quoted in Table I, and shows that the Broken Hill lollingite contains appreciable amounts of cobalt and nickel, and, indicates that the iron is to a considerable extent replaced by cobalt and nickel, so that its formula should be written (FeCoNi) As2This is supported by a microscopical examination of a polished surface of the lollingite, in which no individual arsenides of cobalt and nickel can be detected.Coarse grained galena, sphalerite, chalcopyrite, and pyrite are attached to our specimen of lollingite from the North mine, and are separated by a sharp junction from a mass of lollingite associated with some arsenopyrite and garnet. The massive lollingite can be distinguished from arsenopyrite in the hand specimen by a much brighter, silvery lustre, against which arsenopyrite appears a dull silver grey; but the passage from lollingite to arsenopyrite appears transitional.

Jan 1, 1939

Human-caused global warming has become the environmental cause celebre of the early 21st century. The strong warming alarmist camp currently includes the United Nations, most Western governments, most of the free press, many large corporations (including Enron, before it failed), the major churches, most scientific organisations and a large portion of general public opinion. This phalanx of support notwithstanding there is no scientific consensus as to the danger of human-induced climate change. There is, therefore, a strong conflict between the level of public alarm and its scientific justification. How can this be? In a democracy, the media serve to convey to the public the facts and hypotheses of climate change as provided by individual scientists, governmental and international research agencies, and NGO and other lobby groups. In general, the media have promulgated an alarmist cause for climate change; they have certainly failed to convey the degree of uncertainty that is characteristic of climate science, or a balanced summary of the many essential facts that are relevant to human causation. Climate change is as much a geological as it is a meteorological issue. Natural climate changes, both warmings and coolings, are indeed a societal hazard. We usually deal with geological hazards by providing civil defence authorities and the public with accurate, evidence-based, general information about events like earthquakes, volcanic eruptions, tsunamis and floods, and then by adapting to the effects when a damaging event occurs. As for other major natural disasters, the appropriate preparation for extreme climate events is to mitigate and manage the negative effects when they occur, and especially so for dangerous coolings. Attempting instead to æstop climate changeÆ by reducing human carbon dioxide emissions is a costly exercise of utter futility. Rational climate policies must be based on adaptation to dangerous change as and when it occurs, and irrespective of its sign or causation. The issue now is no longer climate change as such, the reality of which will always be with us. Rather, the issues are, first, the failure of the free press to inform the public about the true facts of human-caused climate change and of the dangers posed by natural climate change. And, second, the vested interests held by many of the groups of warming alarmists. These interests include not only the obvious commercial ones, but also the many scientists and science managers who have discounted or remained silent about the huge uncertainties of the human-caused global warming hypothesis because it suited them to do so. Public opinion will soon demand an explanation as to why experienced editors and hardened investigative journalists, worldwide, have melted before the blowtorch of self-induced guilt, political correctness and special interest expediency that marks the sophisms of global warming alarmists.

Jan 1, 2007

By Turker L

The leaching of Tellness (Norway) ilmenite concentrate in hydrochloric acid and mixed aqueous HCl-alcohol solutions at boiling temperatures was investigated. It was found that the alcohols methanol, ethanol and ethylene glycol all substantially increased the leach rate and in the case of methanol and ethanol this was achieved at lower boiling temperatures compared with aqueous HC.

Jan 1, 1986

By Lewis PJ, Halfpenny R, Craighead GA

Exploration drilling by Joint Venture partners CRA Exploration Pty Ltd and Elders Mining PNG Pty Ltd has discovered a signif- icant copper and gold deposit at the Wafi River prospect, 60km WSW of Lae in Papua New Guinea. An indicated resource of 18Mt at 2.5g/t Au using a lg/t cutoff has been delineated in Zone A. No estimate has been determined for the separate copper occurr- ence at Rafferty's Zone but the copper will be significant to the project. Metallurgical studies on the gold indicate that the primary ore is refractory to direct cyanidation giving a highly variable and inadequate response. All conventional refractory ore oxidation techniques perform well on both ore and pyrite concentrate and oxidation occurs rapidly. No metallurgical studies on the copper mineralisation have been undertaken. Hypogene covellite and chalcocite copper mineralisation is associated with an intensely quartz-stockworked, and quartz and alunite-altered intrusive. Economically significant gold mineralisation occurs in distal subhorizontal lenses, within a sedimentary host, that plunge toward the intrusive. These lenses are sandwiched between overlying quartz and alunite-altered zones and underlying quartz and smectite zones in a mixed zone of quartz, dickite, kaolinite and illite alteration. The alteration and mineralisation is classified as a high sulphidation, epithermal style resulting from the influx of hot, acid magmatic fluids. Preliminary land ownership, road access, power supply and mine infrastructure studies are in progress. The project is currently at an advanced exploration stage.

Jan 1, 1991

By J Bresnahan, D Kepert, R Murray, R Neroni

Stratigraphy of the Hamersley Province in Western Australia, featuring alternating units of banded iron formations and shales with contrasting electrical properties in a mostly gently undulating shallow-dipping layered geometry, is particularly favourable to airborne time-domain electromagnetic mapping techniques. Manipulated vertical cross-sections of modelled conductivity obtained from laterally constrained one-dimensional inversion of SkyTEM304 data enable the exploration geologist to interpret weathering profiles, shallow-dipping stratigraphy and steep structures, all of which are crucial aspects of bedded iron ore deposits genesis models.The Cobra Project is located 14 km east of the NNW-trending Menindee Fault Zone, which defines the western margin of the Hamersley Province, Western Australia. The region comprises an extensive plateau of Brockman Iron Formation cut by a series of horst and grabens with a regional dextral strike-slip component. The 150° striking horst and grabens and associated 060° striking conjugate faults have approximate frequencies of 400 and 2000 m, respectively, and control the bulk of the iron mineralisation. Syn to late 150° trending dykes in part intrude the faults.In the Cobra region, elucidating the structurally dislocated stratigraphy without closely spaced drilling is very challenging. Geological mapping is hindered by the paucity of mappable stratigraphic markers within the banded iron formations and kinematic indicators. Airborne magnetic and remote sensing data sets highlight the dense lineament network, but provide limited assistance in quantifying relatively small apparent displacements, or distinguishing faults from dykes with reasonable confidence.Interpretation of modelled conductivity cross-sections generated from laterally constrained one-dimensional inversion of airborne electromagnetic method (AEM) data offers invaluable insight where the quality of mapping or drilling is wanting. Subsequent targeted field checking and infill drilling validated the geological model interpreted from the integration of these data sets.The AEM technique alone cannot decipher the complex geological environments often present in the Hamersley Province but can facilitate effective iron ore exploration by focusing precious field time and assisting structural and stratigraphic interpretations in areas with sporadic and shallow geological data.CITATION:Murray, R, Neroni, R, Kepert, D and Bresnahan, J, 2017. Using airborne electromagnetics to solve a structurally complex geological puzzle in the Hamersley Province, Western Australia, in Proceedings Iron Ore 2017, pp 269–276 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

The iron ore deposits of the Port Hedland district of North Western Australia are associated with band'ed sedimentary iron formations that form part of the local succession of folded and faulted Archaean volcanic and sedimentary rocks. The iron formations are regarded as the protore beds or sources of the iron which became concentrated by supergene processes to form commercial grade iron ore deposits.Iron oxide deposits occurring in situ within the protore beds are considered to be of residual-replacement origin, due to supergene leaching of gangue minerals and' deposition of secondary iron oxides in their place, Two types of deposit have been recognized. Lode deposits are deep lenses of massive hematite located adjacent to major faults. These deposits are thought to be very old and to have originated by supergene processes during the long period of erosion represented by the major unconformity between the Archaean rocks and the overlying Proterozoic beds. The other type, known as crust ore deposits, are shallow cappings of hematite and goethite on hills formed by the outcrops of steeply dipping protore beds. These deposits could have originated as far back as the early Mesozoic and it is possible that the ore-forming process is continuing at a slow rate at the present day.Deposits formed by erosion and re-deposition of material derived from pre-existing residual-type deposits are known as derived deposits. These include conglomerates and scree accumulations of various types and ages and pisolitic deposits formed by supergene leaching of transported detritus. Derived deposits range in age from early Proterozoic to Recent. The presence of pebble accumulatio,ns of lode-type hematite in the Proterozoic basal conglomerate provides good evidence that lode hematite deposits existed in pre-Proterozoic times.INTRODUCTIONThe existence of iron ore deposits in the Port Hedland district of Western Australia has been known since the beginning of the century, but little attention was paid to them untIl the 1930's, when the Commonwealth Aerial, Geological and Geophysical Survey of Northern Australia carried out investigations of most of the then known mining fields of the Northwest Division. The only iron...

Jan 1, 1964

When studying minerals degrees at university, all the emphasis is towards sending the graduates into the bush to work at a remote mine; however, that is not the only option available to new graduates. There are positions in equipment supply companies, commercial laboratories, research organisations, engineering companies and contractors of many types. The aim of this paper is to show metallurgy graduates that there are non-mine site based career options available to them that offer outstanding career development. This is illustrated by outlining the research being undertaken by Magotteaux Australia and by telling the story of a graduate metallurgist working in MagotteauxÆs small research group. Magotteaux is an international supplier of grinding media and wear resistant components for the mining industry. The Australian research group is focused on determining the effects that the choice of grinding media has on subsequent processing, for example flotation and leaching, by using newly developed tools and techniques.

Jan 1, 2006

By D Craw

Bulk ore tailings from the Macraes gold mine gold extraction process are stored in a large (ca 0.6 km2, 80 m deep) mixed tailings impoundment whose pH is maintained near 8 by natural rock neutralizing capacity. The mixed tailings will be stored in this impoundment in perpetuity after mining ceases. Confidence in the long term environmental stability of these tailings can be gained from examination of mineralogically and chemically similar geological situations in the immediate vicinity. A sequence, typically about 5 m thick, of sands and gravels derived from the Macraes mineralized zone 12 000 to 28 000 years ago contains rounded detrital sulphide mineral grains which are unoxidized despite close proximity to the surface and occasional incursion of oxygenated waters. Saturating water pH is currently 7-8. Sands with 0.2 to 0.8 wt % organic carbon host sulphate-reducing bacteria (SRB), and localized cementation by authigenic framboidal pyrite has occurred. Comparison of the 28 000 year-old sediments with the modem tailings suggests that similar chemistry will prevail, possibly with deposition of authigenic pyrite in the tailings, in the long term. As long as the present slightly anoxic and circumneutral pH environmental conditions are maintained in the mixed tailings dam, sulphide decomposition and acidification are unlikely. These sediments provide a plausible geological analogue for long-term benign storage of the mixed tailings impoundment.

Jan 1, 2000

In a previous paper of this series (1) ,t it was shown that during the creep of single crystals of lead, deformation proceeded to some extent by means of slip on the octahedral plane. This was demonstrated by the formation of slip lines on the surface of the specimens. At first, a few broad bands appeared after a small amount of extension had taken place; then, as extension proceeded, more and finer lines made their appearance until the whole of the specimen surface was covered.The present paper deals with the process of deformation of the creep specimens as revealed by X-ray examination..By the use of this method, the changes taking place in the crystal structure can be observed.EXPERIMENTAL METHODThe method of preparation of the specimens, their size and the purity of the lead employed have been reported elsewhere (1). At frequent intervals, the specimens were dismantled from the test rack and X-ray back reflection photographs were taken. The specimens were so marked and set up on the X-ray machine that the same spot on the specimen surface was always examined.Copper radiation was employed, the tube voltage and current being 45 kV. and 25 m.a. respectively and the exposure time 2 hrs. The slit diameter was 1 mm.

Jan 1, 1941

Difficulties were experienced in the identification of carbonate minerals intimately associated with iron oxides in the so called carbonate ore, which occurs at depth in the Iron Duke Orebody.Determination of refractive indices by examination under the microscope using the immersion method, together with inferred chemical composition indicates that dolomite and parankerite are common constituents. Histograms of the manganese and sulphur contents strongly suggest that manganese is associated with the carbonate minerals, and that the highest sulphur assays occur near the base of the carbonate body.From the present work it is concluded that refractive indices indicate only a very approximate composition for carbonates of the parankerite type.The different carbonate minerals occur in irregular zones.INTRODUCTIONThe Iron Duke deposit is situated in the southern portion of the South Middleback Range on Eyre Peninsula, S.A., 30 miles from Whyalla. (Fig. 1).Drilling at Iron Duke revealed a large body of so called carbonate ore, which was tested in detail at cross section 1000 ft. S by three diamond drill holes, DDH.57, 67 and 78. (Fig. 2)Most specimens of carbonate ore described below were obtained from DDH 67 and 78.GENERAL GEOLOGYThe South Middleback Range is composed of two parallel ridges trending north-south. The Iron Duke orebody is situated on the southern portion of the western ridge. (Fig.1) .The rocks of these ranges belong to the Middleback Group which rests on a gneiss complex. Their age is considered to be Middle Precambrian or late Archaean.

Jan 1, 1963

The Development of a Non-Roasting Technology for Polymetallic Gold and Silver-Bearing Sulfide Concentrates Treatment

Sep 13, 2010

By C G. Ryan, T P. Mernagh, S R. Hunns, R A. Both, R R. Large, J B. Gemmell

 The Hellyer and Mt. Chalmers deposits are mound-style volcanic-hosted massive sulphide (VHMS) deposits in Australia. Textural, petrographic and microthennometric investigations of fluid inclusions in the Hellyer stringer system indicate that Type I, primary, liquid-vapour inclusions are 10 - 15 J.UIl in size, and yield homogenisation temperatures of 170 - 220¦C in early 2A veins, 165 - 322¦C in main-stage 2B veins and 190 - 256¦C in late-stage 2C veins. These data suggest a waxing and waning thermal history. However, the average salinity remained between 8 - 11 NaCl equiv. wt % in all Stage 2 veins. At Mt Chalmers, Type I inclusions up to 20 urn are found in quartz from the mineralised zone, and these inclusions yielded homogenisation temperatures of 160 - 268¦C and salinities of 5 - 8 NaCl equiv. wt %. Laser Raman spectroscopic (LRS) analysis indicates the presence of CO2 (<1 mole %) in the Hellyer and Mt. Chalmers VHMS systems. Semi-quantitative SEM/WDS microprobe analyses of fluid inclusion decrepitates indicate that the Hellyer and Mt Chalmers ore fluids were enriched in potassium and calcium but depleted in magnesium relative to seawater. PIXE microanalysis of fluid inclusions in quartz also indicates a significant base metal concentration in these fluids. Cation composition and higher salinities relative to seawater suggest that recycled seawater alone cannot be the sole source of the ore fluids. High base metal content and the presence of CO2 in the fluid inclusions imply that magmatic input of ore metals during seawater leaching of the footwall volcanic pile is a distinct possibility.

Jan 1, 1995

By J Cahill, D Holden, R Stuart, G Cryan, W Power, W Stratford, S Garwin

The combination of Stage 1 Geoinformatics legacy data intervention processes with the Stage 2 ultra-detailed airborne geophysical prospecting demonstrates a new approach to converting data to information to knowledge, and converting that knowledge into exploration results.   The Coromandel region of the North Island of New Zealand has long been know to host gold deposits of economic viability (Hauraki Gold Fields). To the SE of this area lies the Taupo Volcanic Region (TVR) where the geology and structural setting mirror the Hauraki Gold Fields, however mineral exploration in the past has been hindered by the blanketing volcanic ash deposits. Glass Earth Limited recognised that this whole potential epithermal gold province could be effectively explored utilising rapid, risk orientated processing to review legacy geoscience data: The Geoinformatics Data Intervention Process; which in turn directed ultra detailed airborne geophysical surveys over the TVR. Results have outlined 21 new drillable potential epithermal gold targets; and a plethora of other targets with high prospectivity.

Jan 1, 2005

The commonly used Stopes-Heerlen coal petrographic classification and nomenclature has over the years been subject to variable interpretations. This paper discusses the problem with specific reference to the inertinite maceral group. The effect of various interpretations of the Stopes-Heerlen system on maceral analysis is discussed and illustrated by means of comparative analyses conducted by a number of laboratories in Australia.An attempt is made to define the reflectance thresholds used by the authors to subdivide the inertinite group; the genetic and technological significance of these thresholds are compared.The difficulties of distinguishing structured and nonstructured macerals of the inertinite group are discussed in terms of possible improvements to the present StopesHeerlen system by extending the classification to include transitional maceral types.

Jan 1, 1970

By Greenwood J. N

This work was commenced at a time when information on the manufacture of cemented tungsten carbide was urgently needed in Australia. Much information of a general type has been published, but many of the details of the processes used are still undisclosed. The aim of this research was to determine a satisfactory way in which cemented tungsten carbide could, be made, and to investigate the problems which are associated with the process. As the work proceeded, its ramifications grew continually, and it was necessary to limit the possible lines of investigation. After much experimental work, a 9% cobalt-tungsten carbide alloy was developed which had satisfactory properties when used as a cutting tip. The effect of certain variables on the properties of this particular alloy was investigated.The tungsten carbide was prepared in stages from King Island scheelite concentrates under strict laboratory control, whilst the cobalt (1) used was made from cobalt oxide prepared from crude cobalt oxide obtained from Eisdon.In order to clarify the detailed experimental work, a brief summary of the method used for the preparation of cemented tungsten carbide follows.Tungsten carbide and cobalt are prepared in a very finely powdered state, and are then thor,oughly mixed by a ball milling operation. The resultant mixture is pressed in a suitably shaped die into small compacts which are subsequently '''presintered,'' i.e., heated' in hydrogen between 800°C. and 1000°C. The final sintering is carried out in hydrogen between 1,400°C.and 1,600°C. for about half an hour. These "alloys" may contain from 3 to 13% cobalt, depending on the particular properties required of them.PREPARATION OF MATERIALSThe tungsten oxide prepared as described by Smithells (2) was extremely finely divided, and after a few hours' grinding in a ball mill, the powder consisted of material below 10 microns iJ;l size. The oxide was reduced to tungsten metal with hydrogen in a tube furnace. The reduction was carried out at 800-900° C., a rapid flow of hydrogen being maintained in order to remove the water vapour' formed as a result of the reactions:

Jan 1, 1942

Possibilities and Working of the Specific Agglomeration of Fibrous Materials and Residues Plant based fibrous materials are becoming of increasing interest in a multitude of industrial applications. Main advantages are the specific lower energy demand and virtually closed CO2 cycle, excellent mechanical properties based on low density as well as a high level of recyclables. In contrast, processing and handling of such materials is associated with a number of challenges. These challenges are mainly related to specific morphological characteristics in correlation to fibre length and structure (branching and splices). Specific problems in further processing steps including transport, dosage or storage for natural fibre compounding, result from form-locking bonds leading to burling, clusters or plaits. Technologies of fibre processing are well known, but other than textile based technologies they generally result in intermediate goods which do not allow direct industrial application. The investigation to be presented is based on results of recent research activities and shows two possible technical solutions of innovative fibre agglomeration procedures. These methods allow the conversion of middle to long fibres into a form, which eases further processing and dosage significantly and therefore allows free flowing too. The procedures are based on the working principles of rolling and winding technology. Within the work, both of the patented methods and their respected lab-scaled devices will be described. Further, results will be shown for an up-scaled rolling agglomeration unit applying the developed principle and consisting of multiple process zones. Possible variations of the resulting product characteristics and the impact of different process parameters will be discussed based on the trials with natural fibre (hemp and flax) agglomeration. As a main outcome of the research, product qualities can be supplied according to the requirements of the specific application in correlation to agglomerate strength, porosity or form. In conclusion, recent developments for specific methods of characterization will be depicted.

Sep 13, 2010

The problems of using comparatively simple x-ray diffraction equipment for quantitative analysis are examined. Internal standard and direct calibration procedures based upon the measurement of integrated diffraction energy (diffractometer peak area) have been developed for the determination of quartz in Broken Hill dusts. By these methods an accuracy of ± 10 per cent of the true value can be obtained and this can be improved to ±2 1/2 per cent by statistical methods if necessary.Rapid analysis for the components quartz, muscovite, rhodonite, galena, fluorite, sphalerite, calcite, and garnet has been developed by adaptation of direct calibration procedures and use of maximum diffraction energies (diffractometer peak height). Until more is know!) about the pathological effects of multi-component dusts of the Broken Hill type it seems undesirable to fix theIr allowable concentrations in terms of the quartz content.

Jan 1, 1968

Alluvial gold mining in New Zealand and in particular on the West Coast underwent a renaissance during the early 1980's. This was based on two main factors: a) the sharp rise in the gold price b) the advent of the hydraulic excavator with which to mine the auriferous gravels. The scale of operations varies considerably. A small operation typically consisting of one or two people using an excavator to feed either a land based or pontoon mounted (floating) gold recovery unit, which will typically feature a rotary screen with or without a tailings stacker with the screened fines < 10 - 15 mm) fed over riflle tables. The largest screening plants of this type are operated by DML Resources in their Arahura and Mikonui mining operations where the plants have the capacity to screen up to 250 m3 of gravel per hour. These plants usually employ jigs and centrifugal concentrators for gold recovery. Unique amongst current operations is the Grey River Dredge, a bucket ladder dredge capable of processing 700 m3 per hour similar to those that operated earlier this century. Gold concentration is by a series of jigs. The number of plants operating in recent times peaked at around 130 in 1987 (coinciding with a nominal average gold price of $751) and since that time has steadily declined to 80 units in 1993 and about 45 - 50 units today. This cycle of rapid expansion and then steady decline has been repeated on the West Coast since the original gold discoveries in the mid nineteenth century.

Jan 1, 1996