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By D FitzGerald, S Jakica, R Paterson, J Silic

A new 2.5D airborne electromagnetic (AEM) algorithm has been developed by Intrepid Geophysics and Jovan Silic & Associates. The advantage of 2.5D (2D geology, 3D source) AEM inversion in 3D geological mapping applications and identification of conductive drilling targets, compared to the more commonly used conductivity-depth imaging (CDI) transforms or 1D inversions, are demonstrated using examples from banded iron formations (BIFs) and other geological settings. We show emerging AEM systems are capable of providing estimates of economic rock unit thicknesses, dips and fault definition at an accuracy that mitigates the need for pattern drilling.The 2.5D inversion application used in this work and described in Silic et al (2015) is a substantially changed version of ArjunAir (Wilson, Raiche and Sugeng, 2006), a product of CSIRO/AMIRA project P223F. The changes include a new forward model algorithm and a new inversion solver. The application enables the accurate simulation of 3D source excitation for full domain models inclusive of topography, non-conforming boundaries and very high resistivity contrasts. Solution is accurate for a geoelectrical cross-section, which is relatively constant along a strike length that exceeds the AEM system footprint.The major innovation includes a new inversion solver with adaptive regularisation, which allows the incorporation of a misfit to the reference model and the model smoothness function.Memory usage has been dramatically reduced and is estimated prior to execution. For speed the software has been parallelised using Intel message passing interface (MPI) and can be used on standard computing hardware or computing clusters. Data from survey lines with lengths exceeding 100 km can be inverted on high end laptop computers.We allow flexibility in the selection of components and in the estimation of noise.AEM inversion examples are shown for surveys from BIFs, base metals (volcanogenic massive sulfides) and geological mapping projects and the results are compared with known geology and drilling. We demonstrate the much improved mapping and target definition delivered by this inversion method when compared with the other more common transforms or inversion methods used on these projects.CITATION:Paterson, R, Silic, J, FitzGerald, D and Jakica, S, 2017. High accuracy .D airborne electromagnetic inversion method for banded iron formation and other geological settings, in Proceedings Iron Ore 2017, pp 319–330 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

The work described herein is the opening phase of an extensive system of underground excavation undertaken under contract with a Malayan authority.The specifications called for the lining of all tunnels in earth or broken rock with circular segmented cast iron lining, similar to that of the London tubes, and it is the installation of these linings which it is proposed to discuss.Owing to the long deferred delivery quoted and the obvious need for speed of access to the internal installation, it was decided to defer driving the completed circular section and substitute two small timbered headings.These could later be opened out in turn to full section and lined without prejudice to traffic, since both of them had access to the internal workings.NATURE OF ROCKThe rock series through which the circular sections were driven consisted of:(a) A wide zone of intrusive porphyritic granite, consisting generally of orthoclase phenocrysts in a ground mass of micro pegmatite. This area showed advanced weathering, varying from a stage showing slightly tinted kaolin containing approximately 20% of small boulders to one of ultimate decomposition to pure kaolin;(b) A narrow zone of weathered augite diorite, consisting of rock masses of a maximum weight of some 100-150 tons, isolated by clay seams up to 1 ft. 6 in. in width.The whole area was in a state of quasi-hydrostatic equilibrium, which resulted in heavy pressure immediately after excavation. Freshly broken faces would appear to be quite solid but, within a few minutes, would commence to sweat and "slab off" under pressure and, unless support was placed promptly, the whole face would burst out and run from above. Mucking was slow, owing to the plastic nature of the clay and the ease with which it puddled into slurry.In zone (b) a good deal of trouble was experienced because of the fact that the somewhat heavy blasting necessary tended to cause movement of the large rock masses. Subsequent scouring out of the supporting clay bands by the waterflow permitted settlement of the ground on to the timbers and many reinforcing sets were therefore required.The timbering of the pilot headings and its relation to the cross-section of the circular tunnels is shown in Fig. 1. Top and side spiling was driven in the ordinary way, but in bad ground intermediate sets and breast boards had to be placed. These sets were usually withdrawn after the...

Jan 1, 1941

Project cost control procedures and computer systems have enjoyed a successful and simple relationship over the past decade, thanks primarily to the proliferation of portable computers or PC's. Prior to the introduction of this technology, project control was largely a manual and somewhat onerous task of historical data compilations, with little time available for dynamic forecasting, staged planning, or pre-emptive cost control. Automated systems developed during this era were resident on "Heavy Iron" or mainframe computers and were expensive to maintain and operate. Use of these early systems was limited to large engineering, construction, and industrial concerns with the economies of scale and funding required for their successful application. Systems were either designed for critical path analysis or task scheduling, but rarely integrated with the other, much less cost control.

Jan 1, 1990

A President, soon after he is appointed, sees looming ahead of him the Presidential Address; and in something approaching despair wonders what he can possibly talk about which might hold the interest of his audience. After various casts about, it occurred to me that perhaps prospecting, and more particularly prospecting in Australia, might provide a subject. This is because, 'in the first place, 'prospecting is passing from the stage of chance surface discovery to that of systematic search applying scientific methods to theproblems involved, and in the second, it is the section of the industry with which I have been concerned through much of my: working life. As it makes an address of this sort more interesting if it includes specific reference to actual experience, I hope you will bear with me in such references to actual prospecting as I may use to illustrate the argument. Prospecting has always carried the glamour of sudden wealth. The picture of the prospector engaged, perhaps for years, in fruitless search suddenly coming on riches beyondhis hopes is, deeply etched in the Australian imagination. In few other places has the fervour of prospecting run higher than it did in Victoria in the generation beginning little more than a century ago following the discovery of gold.People arrived from overseas in great numbers. Most of them proceeded to: the goldfields. They moved in thousands from new find to new find. In 'so doing' they determined much of the course of the State's development. The experience of prospectors led them to formulate all sorts of theories little impeded by awkward facts, to account for the apparently unpredictable occurrence of gold.The ideas which men followed, occasionally to success, and which they were prepared to back with all they had were strange and, various, many stories are told of them.

Jan 1, 1959

By G Tripp, G Lorusso

The Velvet gold orebody (153 Koz Au) is located near the Kanowna Belle gold deposit in the Boorara Domain of the Kalgoorlie Terrane, a subdivision of the Archaean Eastern Goldfields Superterrane (Swager et al, 1990). Gold mineralisation at Velvet is hosted within an intrusion of intermediate composition that broadly follows a sub vertical hanging wall splay of the Fitzroy Shear Zone.Velvet was discovered in 2003 during an underground exploration drilling program targeting potential strike extensions to the Kanowna Belle deposit. Diamond drill hole KDU1595 returned a downhole intercept of 36 m grading 4.6 ppm Au approximately 500 m west of the deposit and at a vertical depth of 700 m below surface in the immediate hanging wall of the primary Kanowna Belle host structure, the Fitzroy Shear Zone. Subsequent drilling completed following the initial discovery, from both surface and underground collar positions, failed to replicate this result.In 2014, KDU1595 was resurveyed gyroscopically and the mineralised intercept correctly located. Additional drilling was undertaken to follow-up the repositioned discovery hole. Challenges included poor drilling angles through the Fitzroy Shear Zone, excessive deviation during drilling and the unknown geometry of the target. Navigational drilling helped to successfully penetrate the Fitzroy Shear Zone and in April 2015, drill hole KDU3234 returned a significant downhole intercept of 45 m grading 5.6 ppm Au.Additional drilling success resulted in a decision to develop a 600 m drive to serve as a dual-purpose access for further exploration and mining. This was a potential risk considering that the orebody geometry was unknown and all significant drilling results were clustered within a 50 m × 50 m panel. Development commenced in June 2015 and the first ore cut taken in April 2016. Geological mapping and structural interpretation, together with multi-element and spectral analysis of drill samples has enabled several other target areas to be identified for exploration. The Velvet mining area is critical to continued production at Kanowna Belle. Geological understanding must advance as mining progresses to ensure continued resource growth and optimal extraction of reserves.CITATION:Lorusso, G, Rogers, J and Tripp, G, 2017. Velvet underground exhumed – discovery and development of a new mining front at the Kanowna Belle gold mine, in Proceedings Tenth International Mining Geology Conference 2017, pp 169–174 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

For the purposes of this discussion it is assumed that contributors should express the thoughts that arise from their personal experience. So wide is the range of mineral deposits, and so varied the methods employed in their discovery and development, that no two geologists are likely to have been impressed with the same applications of their science. The author's own personal experience has been, during recent years at least, very largely concerned with the broader aspects of the employment of scientific method and geological knowledge to the problems of exploration and exploitation, for the guidance of the general public and governmental authority rather than of mine executives and directors. The view-point thus reached is likely to differ in many respects from that of men who are much more intimately concerned with the mining problems of a single metal or a single mining field, and for this reason a statement may perhaps supplement those from others whose experience has been markedly different.It may well happen that, at some not distant date in the future, when systematic and comprehensive instruction in economic geology is embodied in the courses- prescribed for mining engineers during their years of training, the author's comments will be quitesuperfluous; but at the present time they appear to him to call for expression.The Need for Training of Mining Men in Economic Geology.Contact over a period of many years with mining men who have had different kinds of training and experience has been convincing that there is a general reluctance to acquire a full rational understanding of the geological factors involved in exploratory and developmental problems. The correction of this attitude is regarded as vital to the industry and it is necessary to insist that the outstanding requirement of the present day is the utilization of all branches of geological, investigation in the field and the laboratoryby men who have had systematic and specialized training in these matters. The science of geology is many-sided, but is, nevertheless, whole and essentially indivisible. No one can afford to disregard any fraction of its content 'or any of its methods of investigation.The greatest advances have been made in the understarnding of the occurrence of mineral deposits by those whose knowledge Qfbasal principles, has been soundest, whose endeavour has been to ascertain all their relationships in space and time, whose attention to detail of all kinds has been keenest, and at the same time, whose capability to distinguish between major and minor features has been most marked.With the passage of the years and the accumulation of data from many lands, it has been possible to build up a great body of information regarding the primary deposition and secondary alteration of mineral occurrences, which is of the utmost value in guiding thesearch for new deposits to take the place of those that become exhausted. This heritage is due not only to the efforts of gifted in...

Jan 1, 1950

The proposed classification scheme is based on two primary parameters, one for petrographic composition and the other for rank, both being determined with microscopic techniques. The scheme has been applied to a wide range of Australian coals and found to provide a useful means of relating their inherent properties to properties such as volatile-matter yield, crucible swelling number, and calorific value, which will determine how these coals might be used commercially.

Jan 1, 1970

SOME notes on the works of the Electrolytic Refining and Smelting Company of Australia will no doubt be of interest to members of the Institute, more especially as much of the work is new to Australasia. As many of the members who may read this paper have not been in a position to visit works of this kind, and are consequently not thoroughly acquainted with all the operations carried on, the author has taken the liberty, in some cases, to enter into explanation which would otherwise be unnecessary. The works are situated at Port Kembla (New South Wales), about fifty miles south of Sydney, and are approachable both by rail and water. The Government has recently built a low-level jetty upwards of five hundred feet long, and intends installing at an early date an electrically operated portable crane to facilitate the handling of material to and from the boats. This will mean: a considerable reduction in the length of time that boats are laid up at the jetty. There are also under construction two breakwaters, which, when complete, will materially assist shipping operation...

Jan 1, 1910

Dynamics of Three Phase Contact Line Motion in Liquid-Liquid-Solid Systems - Impact of Surface Roughness

Sep 13, 2010

The epithermal Au-Ag deposits of the Hauraki Goldfield have formed in the convergent plate margin setting of the Coromandel Volcanic Zone (CVZ). The deposits form as siliceous lodes in the upper parts of geothermal systems associated with andesitic and rhyolitic volcanism. Two types of low sulphidation epithermal mineralisation are recognised in these volcanic terranes. Vein deposits within the rhyolitic terrane in the east and south of the CVZ (Whitianga Province) are typified by Chalcedonic Silica-Adularia-Illite type mineralisation. The veins are hosted by both rhyolite-dacite volcanic rocks and the underlying andesitic basement. The mineralisation formed by episodic violent decompressional boiling of deeply circulating meteoric water, with some magmatic fluid contribution; this boiling was associated with hydraulic fracturing and hydrothermal eruptions in geothermal systems where the piezometric surface of the deep geothermal reservoir lay near-surface. Such episodic boiling provides chalcedonic veining, banding and brecciation textures, adularia stability, bladed calcite, and extreme loss of H2S gas from the fluid to cause major gold deposition.   Crystalline Quartz-Illite-(Adularia-Kaolinite) type mineralisation is widespread in the andesitic terrane forming the northern and western portions of the CVZ (Kuaotunu Province). There is a spatial association with weak mineralisation of the high sulphidation (Vuggy Silica-Alunite-Kaolinite-Illite) epithermal type and porphyry eu-Au type. Crystalline Quartz mineralisation is probably formed by the mixing of shallow acidic groundwaters with the ascending deep geothermal fluid in geothermal systems beneath andesitic stratovolcanoes. The piezometric surface to the deep geothermal reservoir in these systems is likely to lie at considerable depth, with acidic gases rising from the geothermal reservoir condensing within the overlying vadose zone. The cooling effect, oxidation and pH decrease accompanying mixing apparently overcomes the dilution effect, and results in quartz deposition, illite (and locally kaolinite) alteration, and precipitation of gold. A high level of base-metal sulphide precipitation also enhances gold deposition. Violent boiling of the mixing fluids may occur at local structural dilation sites, producing high grade "bonanza" gold mineralisation.

Jan 1, 1991

During the past Two years in reef gold mining, "indicators" have received great attention at the hands at the Victorian gold seekers. Many years ago, what was caned the" indicator lode," was struck in Ballarat East, on the course of which extremely rich deposits of gold were discovered but as to its being a .qeneral experience in reefs or leaders no one ever dreamed. Now, however, we find that these "indicators" are frequently to be met with, though they differ very much in different localities, making it, therefore, a difficult matter for other than a careful minel' to follow them. The necessity of following "indicators" for the purpose of developing gold is now recognized, and the policy of following them up has been attended with much success in this field. In the case of Messrs Shaw and Sons, at Wedderburn, those gentlemen began to work on an "indicator" here five years ago, and immediately thereafter more by accident than anything else they being at that time inexperienced as regards "indicators " came upon gold bearing quartz, which continued payable so long as the" indicator" aud the stone were in conjunction with each other, but as soon as they parted company the stone ceasedto be of any value then, by following the" indicator," as the latter intersected fresh bodies of stone they proved again more or less payable, until a fortnight or so ago the Messrs. Shaw turned out 4 tons of stone, which yielded £1,825, with also profitable workingup to the present moment. Where they are now working is a mile north of their original find thus proving that "indicators" travel considerable distances and have something to do with the gold deposits found in reefs. On the direct course of Shaw's "indicator," as high as hundreds of ozs to the ton was obtained from the stone but, just a few inches from either side in the same" leader," not a colour could be got. Whatever the cause-whether by electricity or some unknown force in nature-the gold is found on the course of these" indicators" and nowhere else, and-as each of the Victorian Government Geologists admit-their value to the gold-seeker as a means of leading to' gold cannot be over-estimated.

Iron ore in the Middleback Range area has a density and susceptibility contrast with adjacent rocks, and gravity and magnetic methods are applicable to exploration for it. The gravity method is satisfactory whether the ore mineral is hematite, magnetite, or limonite; the magnetic method is suitable for detecting ores which contain magnetite, such as some hematite ore, magnetite ore, and possible ore in the form of magnetite-bearing schists. jaspilites, and carbonate rocks.Geophysical exploration began in 1948 and is still in progress. The methods which have been used are aeromagnetic (83 per cent), ground magnetic (13 per cent), gravity (3 per cent), and others (1 per cent). Ground magnetic surveys have been made wherever aeromagnetic surveys recorded large anomalies. The gravity method is being used to investigate those parts of the area considered most favourable for ore occurrence.Qualitative and quantitative interpretation of the geophysical data has been made and the rocks causing selected anomalies tested by bores.Magnetite in the Middleback Group rocks produces the major magnetic anomalies in the area. The average magnetite content of magnetite-jaspilite, which is the commonest rock type, is 33 per cent by weight and that of magnetite-carbonate at the Iron Duke-Iron Duchess is 50 per cent. These rock types also contain hematite and the average total iron content of the former is 35 per cent and of the latter 50 per cent.INTRODUCTIONThe geology and iron ore resources of the Middleback Range area were described by Miles (1954). Since 1954, much drilling, mapping, and quarrying has been done but there is no published report of this work.The rocks which constitute the Middleback Range, Camel Hill-Cooyerdoo line, Katunga Hill-Iron Knob, and Ash Range (Fig. 1) belong to the Middleback Group of Middle Precambrian or late Archaean age. Most outcrops of the Group are jaspilites, formerly called banded hematite (or magnetite) quartzite. The high grade hematite deposits...

Jan 1, 1964

In responding to why some longwall roadway development rates are different among mines, the Roadway Development Task Group (RDTG) of Australian Coal Association Research Program (ACARP) has initiated a benchmarking study to survey each longwall mine to determine the correlation between roadway development practices and roadway development performances. This paper describes a web-based relational database system which has been developed purposely to monitor the performance of Australian longwall roadway developments aimed at assessing both the physical and operational factors which could influence roadway development practices and their performance indicators. Statistical analysis of an earlier survey suggested that continuous miner units that achieved more than 1750 m were units mining two-heading development.

Dec 6, 2010

Electricity will play a major part in providing energy services in the 21st century. Ecologically Sustainable Development (ESD), that is accommodating the needs of the present without compromising the needs of future generations, will provide a focus for optimising the use of electrical energy. Environmental externalities may redefine the cost structure of electricity. Strong corporate environmental management will ensure that current environmental objectives are met and that future ones, identified by the ESD process and environmental externalities accounting, can be developed and implemented by receptive business managers. This paper addresses the current environmental issues of electricity production. It outlines a management strategy for the SECV becoming a community leader in protecting the environment. ESD is discussed in terms of using non-renewable resources wisely, extending their availability and putting in place mechanisms which ensure their ultimate substitution by renewable resources and conservation. The paper explores options for dealing with costing environmental externalities, particularly in relation to greenhouse emissions.

Jan 1, 1992

By Bibby P. A, Leupen R. A

A 24,300 tonnes per year state of the art Silicon smelter is being constructed for Barrack Silicon Pty Ltd at Kemerton, 20 kilometres north of the City of Bunbury in Western Australia. The plant is designed for the reduction of high purity quartzite lump to metallic silicon in two 27MVa Demag submerged arc electric furnaces. The primary reductant, a high purity charcoal, will be manufactured at the plant from locally sourced jarrah wood waste (Eucalyptus Marginata). Commercial silicon production is scheduled to commence in October 1989. Keywords: Silicon, Smelter, Quartzite, Furnace, Charcoal, Jarrah, Wood, Eucalyptus Marginata.

Jan 1, 1989

Ore sorting is a high capacity, low cost method of pre concentrating ores and in some cases of producing a marketable concentrate. In most cases it is applied to run of mine material, immediately after primary crushing and screening in sizes ranging from 10 mm to 150 mm. Recent developments in bulk sorting of friable uranium deposits have resulted in machines capable of handling fine materials with sensing and separation being achieved on a zone by zone basis. Modern ore sorting machines rely on the synchronous operation of four internal subsystems, feed presentation, sensing, data processing and separation. A variety of different sub systems is available which can be combined in various forms to produce sorters capable of handling a wide variety of mineral types. The benefits in using ore sorting cover a wide range of situations and are applicable to both established mines as well as new mining ventures. Reduced operating costs, increased productivity, capital savings, energy and resource conservation and environmental issues are all part of the reason why ore sorting is finding rapid acceptance in today's mining industry. The suitability of different ore types for pre-concentration using anyone of the variety of ore sorting systems can be quickly established using computer based techniques which require only small samples of the materials under investigation.

Jan 1, 1980

By L Mottola

Three decades ago mining companies, principally in North America, aided by machine and explosive manufacturers, started significant attempts to develop and implement automated mining systems, mainly underground. These tended to be motivated by decreasing cost, increasing productivity, reducing labour requirements, and improving safety. These are important business drivers, however, little attention was given to the underlying goal of mining automation, namely to bring upstream processes in control and reducing variation, as seen in downstream mineral processing plants.This paper first reviews the nature of Lean Thinking and its application in the context of the growing commitments by industry to develop future automated mine production systems. The paper then makes reference to prior and current experiences in open pit blasthole drill and shovel performance monitoring, to demonstrate the principle that machine performance data offers as a means, not only to characterise the dynamic geological and working environment, but also to provide a foundation for automation. In this case, drill and shovel monitoring was originally motivated as a means to optimise blast fragmentation through more effective drill and blast designs that are based on an accurate determination of the bench geological and geotechnical characteristics, hence managing variation in the drilling and blasting process. This paper considers how automating and integrating such components of the mine production system would bring processes into a controlled state, creating value at the face, within a framework of Lean mining.

Nov 22, 2011

By Met M, Worner H. K

In pursuance of the investigation into the influence of various elements on the properties of lead during the past year, the effect of several elements on the creep rate of commercially pure lead has been investigated; a standard initial stress of 500 lb. per sq. in. having been adopted for comparison purposes. Other work which has been carried out indicates that the relative results of creep tests may be altered by varying the applied stress, but this aspect of the problem will need to await further investigations for itscomplete elucidation. The results obtained with dilute tellurium alloys are considered sufficiently interesting, and in some respects are so extraordinary, as to warrant publicatiorr at this stage.n must be realised however that, since the results obtained appear to be at variance with those said to have been obtained in practice and those previously published, the present investigation can only be considered as a contribution to our knowledge of the general problem.Consequently it is not considered advisable or necessary to offer detailed explanation of the results given. In fact, some features of the tests about to be described will need further investigation before an adequate explanation is possible.

Jan 1, 1936

By V N. Rudashevsky, F Melcher, J Lodziak, D Klosa, N S. Rudashevsky, M Sitnikova, L Gast

A combination of novel and æclassicÆ methods, namely electric pulse disaggregation (EPD), hydroseparation (HS), preparation of monolayer polished sections, and mineral liberation analysis (MLA) was employed to study ores from platinum pipes (Bushveld Complex, South Africa), pristine PGE mineralisation of the Main Sulfide Zone (Great Dyke, Zimbabwe), as well as ancient and modern gold/PGM placer deposits. It is shown here that the EPD technique liberates mineral grains of interest without any visible destruction allowing the study and analysis of individual rock-forming and ore minerals, in our case especially platinum-group minerals. The HS method is an effective tool in concentrating heavy minerals by factors up to 10 000 fold. As near-total recovery of grains >10 ¦m is achieved, the nugget effect can be overcome also in case of limited availability of samples (drill core, museum specimens). The MLA technique is a fast tool to detect and characterise mineral phases in ores and ore processing products. Many mineralogical parameters of individual grains and mineral assemblages can be deducted and documented. The results show that the techniques employed, either on their own or in combination, provide a wide range of additional information especially on platinum ores which is beneficial to both the researcher and the metallurgist.

Jan 1, 2008

Single particle breakage tests have been used by a number of researchers to investigate some salient features of the complex comminution process. The characteristics of the common single particle breakage tests such as single impact, double impact and slow compression tests are examined and the results from these tests are compared. A comparison of the results from single particle breakage tests with grindability and ball mill tests is given. Application of the results from single particle breakage tests to modelling industrial comminution processes is described. The necessity for further research into single particle breakage tests to develop a simple but comprehensive technique for estimating the breakage characteristics of ores is discussed.

Jan 1, 1986