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Rock formation at shallow depths is generally associated with complex geology consisting of many joints, fractures, bedding planes, etc. Fragmentation results from primary blasts in such strata are therefore significantly influenced by structural discontinuities. To evaluate the role of discontinuities, which is of great use in the design of blasts in such conditions, a two-stage investigation program was taken up. In the first stage, model scale tests were conducted with single and double holes with the strike of discontinuities parallel and perpendicular to the face. Later, field studies were conducted in a limestone mine and a coal mine. Blast patterns were modified based on the results obtained from model scale blasts. Secondary blasting was taken as a measure to assess blast performance in the field, whereas mean fragment size, fine and coarse fragmentation indices were considered as fragmentation measures in model scale tests. Model tests indicated confinement of explosive energy by the discontinuities surrounding blasthole. Crater shape and size were significantly influenced by the orientation of joints with respect to the face. Modified blast designs with decreased burden x spacing patterns resulted in improved fragmentation in the field. A reduction of about 12 per cent in explosive consumption was recorded with modified blast designs. Boulder formation was observed to decrease by about 79 per cent as well.

Jan 1, 1995

By Drury SA, Williams RD, Nind DC

The Airborne Thematic Mapper is an eleven channel digital scanner which acquires image data in the visible, near infra-red, short wave infra-red and thermal infra-red wave- lengths. A description of the system is presented which includes details of the operating wavelengths and performance parameters of the scanner. Consideration is also given to the aircraft installation requirements. During January 1984 the scanner surveyed the mineral rich areas of Leonora, Laverton and Kalgoorlie in Western Australia. This is a region of intense exploration activity for gold and base metals. Some 30,000 square kilometres were systematically surveyed in a period of ten days. This scanner was flown at 7,000 metres altitude giving a ground pixel size of 17.5 by 17.5 metres. The flight line spacing was 8 kilometres. The overall project took some thirty days from conception to completion. The planning and execution of this operation are described in detail. The resulting magnetic tapes provided 11 channels of digital image data over a 30,000 square kilometre area and a variety of image processing techniques were employed in order to capitalise fully on the results. The imagery provides a powerful tool for the geological mapping of the terrain. The data can also be used to monitor the environmental effects of mining operations.

Jan 1, 1986

In the current climate, there is a real need to bridge the gap between theory and the real world mining considerations, and develop viable, cost-effective, high performance thickeners. With a greater need to extract profits from both difficult-to-process ores and lower grade orebodies, coupled with the necessity to produce 'greener', less water intensive technologies, suppliers need to take current thickener designs to the next level and into the 21st century. The complexity of 'getting it right' within a thickenerÆs feedwell, the 'nerve centre' of the thickener, is no small task. Delivering dilution water and mixing this water with incoming feed slurry, addition of flocculant, maximising flocculant-slurry interaction to build aggregate size, minimising unabsorbed flocculant percentage, volume average of solids volume fraction, momentum dissipation ratio, dilution recycle ratio, volume average shear, maximum shear rate at exit, aggregate size on exit, uniform discharge profile and more ù all of these need to occur in the right order and in the right proportions within the feedwell. This paper discusses the genesis and evolution of a new feedwell design, the first major innovation in the thickening industry in over 15 years.

Jan 1, 2008

By Jones BH

Discovery of the Vera-Nancy deposit in late-1995 followed 12 years of active exploration in and around the Pajingo Epithermal System, an andesite hosted veinfield covering an area of 150 square kilometres at the northern end of the Devono-Carboniferous Drummond Basin in North Queensland. Early exploration targeted open-pittable resources in the numerous auriferous veins and it was not until 1994 that exploration focus shifted to drilling to depths below about 100 metres from surface, which resulted in the Vera-Nancy discovery. That deeper drilling process is still at a very early stage of coverage of the epithermal system as a whole and substantial potential exists for additional discoveries.Drill-out of Vera-Nancy has to-date established a gold resource in excess of 1.4 million ounces. Mine development is proceeding via a twin decline system with first stoped production scheduled for August 1997.

Jan 1, 1997

In order to understand the technique, basic theoretical principles of radiation emission and in- strumentation theory are reviewed. Methods of surveying, reduction of data and interpretation are outlined. Other applications of the technique (e.g. in airborne geological mapping), as well as its specific use in uranium exploration, are discussed. By means of case history-type examples the successful applicant of gamma-ray spectrometry, as a tool in Australian mineral search, is demonstrated.

Jan 1, 1969

By Lockhart D. A, Gleeson P, Lang S. C

The Glenrock Group forms the uppermost part of the Early Devonian to Early Carboniferous Burdekin Basin sequence in the Townsville hinterland, north Queensland. As redefined, three formations make up the Glenrock Group. The Percy Creek Volcanics (base), the dominantly epiclastic Mount Douglas Formation, and the Horse Pocket Volcanics (top). The Ellenvale beds unconformably overlie the Mount Douglas Formation and Percy Creek Volcanics and have been excluded from the Glenrock Group as defined by Wyatt and Jell (1980). Three facies associations are recognised in the Mount Douglas Formation: Alluvial Plain facies, Alluvial Fan facies and Lacustrine facies.Deposition of the Glenrock Group, began with the eruption of massive basalt and basaltic andesite lavas, probably in a volcanic arc setting. With time, the volcanism evolved to become more dacitic to rhyolitic in composition. Waning of the volcanic activity appeared to coincide with uplift of source areas (probably to the west). Deposition on an alluvial plain during this waning volcanic cycle, gave way to alluvial fans at the margins of the uplifted terrain. As the uplift ceased and the system became more mature, the alluvial fans gave way to widespread lakes. Rhyolitic ignimbrite and airfall tuff, interbedded with the alluvial plain, alluvial fan and lacustrine facies, indicate that some volcanism continued, probably vented in the uplifted terrain to the west.

Jan 1, 1990

By Frith RT, M D. Goodz

Drilling has been accepted as a major exploration tool. However its use in mine planning and development has been overlooked.This need for drillhole data was highlighted during the redevelopment boom of the central Victorian gold mines. During the 1980's numerous old mines were evaluated and successfully drilled to yield mineable parcels of quartz reefs close to existing workings.Invariably the initial decision was always to attempt reopening and rehabilitating existing access. The four case studies described have proceededsufficiently to show that major cost savings would have been made if underground drilling had been used as the main tool in mine planning.Savings not only in expenditure, but in the time required to make key decisions. In two cases the mines would have experienced far earlier expansions in production. In one case the mine would be currently producing rather than awaiting further finance. In the fourth example, the decision to case development would have been much earlier providing capital to other projects.

Jan 1, 1990

By Jones M

The concept of precise, accurate timing with Electronic Delay Detonators (EDDs) was first seriously addressed in the mid-1980s and much was made of the cheapness and profusion of digital watches in terms of the likelihood of EDDs also being cheap and easy to produce. Ten years later, with every major explosives company and many electronics groups having instituted projects to capitalise on the promise of these devices, production devices are still to come into general use. In South Africa, Expert Explosives units have been used in most applications during proving trials and more recently for production blasting in underground ring stoping and open cast coal. The outcome has been valuable learning both as to the benefits and technical requirements for electronic delay blasting, and especially, safety aspects. Examples are shown of production blasts which utilised the power of EDDs. It is evident that it is not delay accuracy alone which determines the value of these systems, but the whole robustness, flexibility and ease of delay allocation when harnessing blast engineering knowledge. Muckpile movement and shape, fragmentation and vibration frequencies have shown to be greatly influenced by designs which can be implemented no other way. The flexibility of a system and the power of the software controlling it are crucial in capitalising on blasting potential, which lies in integrating control of blast timing with other developing electronic Technologies.

Jan 1, 1995

The known coal resources of South Australia are either of poor quality, or expensive to extract, or both. Export quality coal occurs only at great depth in the remote north of the State; the balance of the State's coal resources are suitable only for local electricity generation. Currently there is only one coal mine in the State, at Leigh Creek. This provides fuel for approximately 34% of the State's electricity generation, the balance being fuelled by natural gas. In the near future, new fuel sources must be developed to augment diminishing supplies of natural gas, and to cater for increasing demands for electricity. The South Australian Government has determined that future electricity generation will be based on the combustion of local coals. The geological and geographical environment of the known coal deposits and the quality of these coals are such that the most up to date and innovative technology must be applied to both extraction and combustion processes. The Government, the Electricity Trust of South Australia, and several Australian and overseas companies have embarked on an extensive research and development programme to ensure that these otherwise useless resources can be developed to the benefit of the State.

Jan 1, 1987

By K Williams, T Donohue, W Chen, T Roessler, A Katterfeld

Wet sticky iron ore poses particular difficulties in every aspect of the material handling process. Material hang-ups in bins, pipes and chutes; carry-back and spillage due to insufficient belt cleaning; clogging of screens; malfunctioning of crushers as well as rat holing of gravity reclaimed stockpiles are all predominantly due to the inherent cohesion and adhesion characteristics of the wet, sticky ore (Roberts, 1993). Limited understanding and quantitative measures on the stickiness of such a material significantly lower the mining operation efficiency.This research aims to investigate the cohesion and adhesion characteristics of the wet, sticky ore on physical modelling, experimental techniques and numerical implementation. Initially, the suitable bridging mechanism that contributes to the cohesive and adhesive forces within the iron ore material was identified (Hering, Martin and Stohrer, 1989; Rumpf, 1958). A cohesion/adhesion energy density factor based contact model was then introduced to describe the stickiness of the material. Secondly, an experimental system was proposed to directly test the stickiness of the material. Such a system is able to obtain both the cohesive/adhesive shear force and tensile force of the material at a specific moisture content. Lastly, the implementation of the proposed cohesion/adhesion model into the discrete element modelling (DEM) software was also discussed. A cohesion/adhesion calibration for modelling wet sticky iron ore in DEM was then conducted to ensure the material modelled in the simulation is reflective of the reality.From the study, understanding of the cohesion/adhesion characteristics of the wet iron ore material is significantly enhanced. Experimental and numerical outcomes can be directly applied for better designing or optimising the material handling processes that involve wet sticky iron ore. Consequently, the mining operating costs can be greatly reduced.CITATION:Chen, W, Donohue, T, Williams, K, Katterfeld, A and Roessler, T, 2015. Modelling cohesion and adhesion of wet, sticky iron ores in discrete element modelling for material handling processes, in Proceedings Iron Ore 2015, pp 387–392 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

The main features and recent developments in the processes of benefication and extractive treatments of tin ores are reviewed. The need for development of processes to recover fine tin, tin from low-grade complex ores and from hard rock resources is indicated. The progress in understanding of slag-metal interactions and developments of fuming processes on industrial scale is delineated. the processes and prospects of hydrometallurgical and chlorination methods are briefly indicated.

Jan 1, 1992

Newmont Australia Limited has for some 15 years mined a number of large open cuts associated with the Telfer Gold Dome deposits. The principal ore body exploited has been the East Flank of the Main Dome where a very high grade gold reef deposit of mixed metal sulphides, grades in excess of 20gA Au, has been mined in conjunction with dissemi- nated mineralisation contained in the overburden material. The main ore body has been under review for some years as an under- ground mine, however due to the ore body widths of less than 1 metre and a dip generally less than 35 degrees and a very weak host rocks earlier studies all resulted in a continuation of open pit mining activities. In early 1988 it was recognised that open cast mining would not be able to mine all of this valuable resource and a feasibility study was commenced to come up with a practical and economic approach to underground mining.

Jan 1, 1991

By K L. Avarmaa, M A. Rhamdhani, A D. P Putera, H T. B M Petrus, G A. Brooks

Multistage slag treatment was carried out to investigate boron removal from metallurgical grade silicon. Boron is known to be one of the most difficult elements to remove from silicon. Depending on boron initial concentration, boron can be removed from silicon into certain level; most previous studies have attained final 50–100 ppmw (parts per million weight) boron in the silicon using slag treatment. The term ‘multistage’ refers to a process where the resulting silicon from the initial slag treatment is further refined multiple times using a new slag. In this study, an initial slag composition of 45CaO-45SiO2-10Al2O3 (wt per cent) was utilised. Using this technique, boron level in the silicon was expected to be gradually lowered because the new slag will always have more capacity to reach the equilibrium distribution coefficient (LB = (ppmwB)slag/(ppmwB)Si). The current study was carried out through combined thermodynamic calculations (using FactSage™ ver 8.2, by Thermfact Ltd, thermochemical package) and high-temperature experimentation. The thermodynamic calculations were carried out for reactions at 1500, 1550, and 1600°C for three different scenarios: 1. Single stage refining with varied slag to Si ratio. 2. Multistage refining with slag to Si ratio of 1:1. 3. Multistage refining with slag to Si ratio of 2:1. The multistage experimental work was carried out at 1550°C under inert gas atmosphere each time for 2 hrs, with slag to Si ratio of 2:1. The simulation results indicate that the boron distribution coefficient stay essentially constant with varying slag to Si ratio and temperature, around 1.8 to 2, and the experimental results measured LB in the same range, between 1.5 and 2.5. By harnessing this feature, the simulation showed that boron can be removed by approximately 78 per cent in each stage. The experimental result confirmed that the boron concentration in the silicon was reduced by a total of 97.8 per cent from its initial value using four stages of slag treatment, from initial 270 ppmw down to 6 ppmw.

Aug 21, 2024

INDEX OF CONTENTSBlast Furnace SlagsForehearth AccretionsConverter SlagsConclusionsIllustrationsCOMPOSITION OF SOME COPPER SLAGS FROM PORT KEMBLASamples of copper slags from the Port Kembla Smelter of the Electrolytic Refining and Smelting Co. of Australia, Pty. Ltd., have been submitted for mineragraphic examination, with reference to the mode of occurrence of copper in them. The samples included (I) blast furnace slags, (H) a forehearth accretion, and (IH) converter slags. 1. BLAST FURNACE SLAGS Four series of samples of blast furnace slag have been submitted. The. chemical compositions of the several slags are shown in Table 1. Analyses Nos. 1 and 2 are of samples of slowly or normally cooled slag, taken from the slag dump, Analyses Nos. 3 and 4 are of samples comprising slowly or normally cooled slag, together with granulated slag from the same melt.

Jan 1, 1949

By Stitt P. H

This paper provides a brief historical review of the invention of the spiral separator and its adoption into Australian metallurgical practice. The purpose of the review is to demonstrate that spiral development to date appears to have been a largely empirical process, and that the cur- rent resurgence of interest in the spiral, especially in the coal industry, warrants an increased fundamental research effort. Current research work concentrating on empirical modelling is outlined, while some preliminary experimental results of a more fundamental nature are presented and some research of other disciplines interested in particle transport introduced in order to stimulate further work and discussion.

Jan 1, 1988

By Duniam P

Sequencing of large underground firings is a critical aspect of blast performance. Using theory developed in open cut operations, where blast results are easier to quantify, a new technique for sequencing underground mass blasts has been developed. The basis for the technique is to identify timing regimes to control fragmentation and relief then apply non-electrics to fit these criteria. The use of computer software to graphically interpret delay statistics enables the evaluation of designs in a realistic manner.

Jan 1, 1995

By D MacKenzie

The Rise & Shine Shear Zone is a shallow-dipping Cretaceous late metamorphic shear zone formed in a compressional environment. The Shotover mineralised system is dominated by normal faults with well-defined vein systems that cut across Miocene schist folds and faults related to the inception of the Alpine Fault. Despite the geological differences between these mineralisation systems, they share many common features of hydrothermal alteration that have resulted in disseminated gold in altered sheared schist. The most distinctive feature of both systems is the abundant ankeritic carbonate that has formed from decomposition of metamorphic chlorite. Excess iron from this alteration reaction combined with hydrothermal sulphur to form sulphides that host the disseminated gold. The chlorite decomposition reaction was reversed in the latter stages of both mineralisation systems, and this was accompanied by further gold emplacement in the Rise & Shine system.   Both alteration systems involved initial decomposition of metamorphic albite, followed by deposition of albite as a vein mineral in the latter stages. The fluid flow that yielded the disseminated gold was controlled by microshears that pervade host schists, in strong contrast to many Otago Schist vein systems where host rock alteration is absent. The ankeritic alteration in the Shotover and Rise & Shine mineralised systems has increased the volume of mineralised rock, and may have made suitable targets for large-tonnage, low grade gold deposits.

Jan 1, 2007

The Mineragraphic Section of the Council for Scientific and Industrial Research has had occasion from time to time to examine rocks, ores and concentrates from the Yatukoula goldfield, Fiji. The results of the examinations have been supplied as Mineragraphic Reports and have been supplementary to various investigations carried out by the mining companies on ore treatment, or by visiting geologists on the nature of the rocks and lodes. The presence of tellurides was determined in 1935, though incorrectly as nagyagite. The general absence of lead, except in traces, was soon afterwards discovered, and it came to be recognised as the mines were opened up that the chief telluride minerals on the field were sylvanite and native tellurium. Specimens of the tellurides have been provided from time to time by E. G. Theodore, Managing Director of the Emperor Mines Ltd., and of the Loloma (Fiji) Gold Mines N.L., and further material was recently obtained, as the result of a visit to the field at the invitation of Mr. Theodore.The aim of this paper is to describe the occurrence of the tellurides in these specimens. The work has been carried out as part of the programme of research of the Mineragraphic Section.THE VATUKOULA GOLDFIELDThe Emperor, Loloma and Dolphin mines are situated at Vatukoula, six miles, south of Tavua, on the north coast...

Jan 1, 1949

By Barns K. E, Munro P. D, Brindley S. K

Ernest Henry Mining Pty Ltd started production in August 1997. The Ernest Henry orebody consists of two distinct parts, a complex supergene ore zone overlying a primary ore zone. The economic copper minerals in the supergene ore are chalcocite

Jan 1, 1998

The Tom, East and West zone, stratiform Zn-Pb-Ag deposits at Macmillan Pass, Yukon, Canada were discovered by Hudson Bay Mining and Smelting Co Ltd prospectors in 1951. Further exploration, including two phases of underground exploration produced an HBM&S calculated reserve of 9.28 Mt of 7.5 per cent Pb, 6.2 per cent Zn and 69.4 g/T Ag for these zones. Cominco Ltd optioned the property in 1988. Deep, surface drilling extended the West and Southeast zones downward 200 - 300 m, indicating an additional potential resource of several million tonnes of good grade. The magnitude of the controlling syndepositional setting suggests that mineralisation continues to greater depth but with increased drilling and possibly mining costs. The 30 x 60 km Macmillan Fold belt trends WNW across the NW Selwyn Basin and Cordilleran trend. Within the fold belt, the Central Block - a complex, rift controlled basin of Devonian siliciclastics, hosts seven zones of Pb-Zn-Ag mineralisation clustered about four hydrothermal centres. The centres, distributed over 24 km, are coincident with small syndepositionally active structural sub-basins. The Tom deposits, in one such sub-basin, are localised by a third order structure consisting of two palaeobathymetric troughs flanking a syndepositional horst. This structure caused drastic facies and thickness changes over 600 metres of strata and focussed the venting of hydrothermal fluids through permeable conglomerates in the horst and its flanking growth faults. Mineral facies are zoned, with Pb-Ag contents rapidly diminishing outward from the vent resulting in restricted areas of high grade Pb-Zn-Ag-Ba ore within more extensive, sub-economic, Ba-Zn mineralisation. Widespread iron carbonate alteration of the footwall and high Si, B and Zn values in the hangingwall 'fingerprint' the deposit and along with the distinct facies variations provide aids to exploring the Tom and like deposits.

Jan 1, 1993