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In gold ores, the range of value disclosed by ordinary mine sampling is very wide, and the number of 'samples required for a reliable average is correspondingly great. Even where a large number of samples is available the weighted mean value of the samplesalmost invariably exceeds the true gold content. In operating mines this disparity is overcome by arbitrary reduction of high assays until reconciliation is achieved, but it is frequently necessary, especIallyin exploration, to base an estimate or to reach a decision on a relatively small number of samples from underground openings or even on a few drill hole intersections. In these circumstances, a decisive influence may be exercised by the weight allowed to high assays and to low grade intersections, both of which events are, of course, dependent on the metal distribution in the ore. Where sufficient data are available, statistical analysis will measure the risk involved, but as this information is seldom to be had, the final choice becomes largely a matter of personal judgment.With this problem in mind, a study was made some years ago of the distribution of values in four Western Australian gold ores, with the primary purpose of learning from actual ore-bodies of differing types, something of the metal distribution in the smallquantities of ore involved in individual routine mine samples, and of the importance in each case of high assays. Adequate and suitable data were available in .four cases, in three of which high assays were of frequent occurrence due to the presence of free gold. The results give concrete expression to well known differences of metal distribution, and it is proposed, firstly to record the observed distribution; secondly to examine some of the consequences of the differences in the distributions limd thirdly, to comment, in the light of this data, on the vexed question of the treatment of high assays. Standard statistical procedure was employed in the compilation of the data. The assays were classified by value into groups, each group covering a range of value of 1 dwt. per ton. Assays of less than 1.0 dwt. per ton form the first group; assays equal to or greater than 1.0 dwt. and less than 2.0 dwt. comprise the second group; those equal to or greater than 2.0 dwt. and less than 3.0 dwt. appear in the third group; and so on. Where the number of samples is large, it can be assumed that the mid-value of the group is the mean value of all the samples in the group, thus the mean values of the first three groups are 0.5 dwt., 1.5 dwt. and 2.5 dwt. respectively.The number of samples in the group is the frequency of the group, but for convenience of plotting this frequency is converted into percentage of all the samples in the series. Plotting percentage frequency as ordinate against dwt./ton as abscissa results in a frequency curve-a curve showing the frequency...

Jan 1, 1950

By using knowledge-based technology to create a Virtual Mining Enterprise and integrating it with existing technical and financial computer systems, a gold mining company has been able to reduce the time taken to produce a mine plan from 14 weeks to less than one week. Typically, the mine planning process requires circulating and managing large amounts of information. Even with the use of computers in todayÆs business, this is often still a manual process involving file transfers and individualised spreadsheets. Mine planning also involves understanding and managing large quantities of complex and interrelated variables. Added to this is the ever changing dynamics and constraints associated with the business of mining. These issues not only hamper the planning process but also question the validity and usefulness of the mine plans being generated. By integrating the information and knowledge of the numerous departments involved in mine planning into one core Knowledge Base - so called æone version of the truthÆ, - mining companies are able to overcome these pitfalls experienced in traditional planning methods. Once set up, the Knowledge Base creates and runs a virtual mining enterprise with which to visualise and test various scenarios of mining, business and logistical activities. The final output is an optimised enterprise-wide plan with clear and detailed instructions for each of the divisions of the company.

Jan 1, 2000

By Patterson J. H

An infra-red absorption study has been made of crocidolite, country rock. and associated host rocks from Wittenoom Gorge. The spectrum of the country rock is appreciably different from those of crocidolite and the magnetite-rich host rocks which are closely similar. A process to separate crocidolite-bearing ore from country rock based on infra-red emission is therefore possible in theory.

Jan 1, 1966

Extraction and Characterisation of Extracellular Polymeric Substances from the Mineral Surface During Bioleaching of Chalcopyrite Concentrate A mixed culture of moderately thermophilic microorganisms was used to bioleach chalcopyrite concentrate in a stirred tank reactor. The results show that up to 84.7 per cent of copper extraction could be achieved in 24 days at a pulp density of 6 per cent. The leaching rate of chalcopyrite concentrate tended to increase with an increase of dissolved total iron concentration. Furthermore, the extracellular polymeric substance (EPS) on the surface of the chalcopyrite concentrate was extracted and analysed. EPS was extracted at the first, third, eighth, 16th and 24th day during bioleaching, which mainly consisted of proteins, lipids, sugars and ferric irons. After the eighth day the total amount of EPS remained relatively constant. However, the amount of ferric iron in the EPS decreased in a large scale. The ore residue analysis indicates that the decrease of ferric iron was mainly due to the formation of jarosite on the mineral surface.

Sep 13, 2010

By L Maw

New ZealandÆs largest gold producersÆ OceanaGold Macraes Mine is characterised by a large tonnage and relatively low grade operation. To survive in diminishing real gold prices, the operation must focus on a culture of continuous improvement. This paper presents the outcome of a supplier sponsored continuous improvement project known as the Orica Advanced Mining Services project.   In March 2004 OceanaGold (then GRD Macraes) entered into an Advanced Mining Services (AMS) project with Orica Mining Services. The motivating factor behind OceanaGoldÆs need to improve bulk waste productivity and SAG mill throughput was the planned increase in production from five million to 5.4 million tonnes per annum. A stripping ratio of ten to one meant that optimisation of the drill, blast and production functions was paramount.   The primary focus of the project was to optimise the drill and blast parameters to suit the variable rock conditions throughout the mines main operating pit (Frasers Pit). Fragmentation of the ore for presentation at the SAG mill, and cost reduction on the mining of bulk waste movement, were the primary objectives. A number of additional initiatives complimenting the interface between drill, blast and ore production were also established. These included; +        reduced ore loss through delineation of ore boundaries to allow for blast movement; +        established blasting parameters for variable geological conditions, resulting in improved fragmentation; and +        improved asset utilisation by establishing a blasting regime that angled grade control holes to be used as blastholes in the stockworks area.   A year into the project, the philosophy of continuous improvement is now in-grained at the Macraes minesite. As the project continues, the focus is on the further refining of those procedures established, to ensure a continued focus on lower unit mining production costs.

Jan 1, 2005

By K H. Esbensen

The Theory of Sampling (TOS) has made remarkable strides and has witnessed a suite of achievements over its ~65-year history; especially in the last 15 years, since organised work began for the erstwhile fragmented sampling community (2003). Theory and practice have been very well exposed and disseminated, as witnessed in the successful series of the World Conference on Sampling and Blending (WCSB) events and other dedicated sampling and mining conferences in Australia and South Africa. At this WCSB8 occasion we fittingly devote a section of our conference to celebrate the life and monumental achievement of Pierre Gy, the originator of the Theory of Sampling; a special issue of TOS Forum was recently published to the same purpose. But TOS is most emphatically not a finished work.Here I try to look into the future with a personal view: TOS – what’s next? Commensurate with this objective there is offered some out-of-the-box thinking. The purpose is to try to zoom in on probable additional future aspects of TOS and its application compared to the first 15 years of our common journey. There are bound to be lacunae here-and-there across the vast application horizon delineated, which is as it should be, as this lecture is meant to initiate a broad(er) debate – and readers may agree with all, parts, or none of the topics presented. All is well that furthers this debate.CITATION:Esbensen, K H, 2017. Theory of Sampling – what’s next?, in Proceedings Eighth World Conference on Sampling and Blending , pp 29–38 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

The mineral composition and microtextures of a cubanite-rich sulphide ore are described and cubanite breakdown textures are illustrated. The occurrence of cubanite in macroscopic dimensions is featured.The origin of the ore is tentatively related to a composite ore fluid arising initially from an ultramalic source and extracting some metal components from an older granite mass along the margin of which the serpentine was emplaced. Some alternative possibilities as to origin are also mentioned.

Jan 1, 1969

By Pfeifer H. C, Nicacio P. A D

Sinter has been used as part of the metallic charge in large-scale blast furnaces for many years with the well-known benefits in terms of productivity and fuel consumption. However, because of the high investment in a conventional sinter plant, small blast furnaces and the associated integrated mini steel plants have not taken the advantages of using sinter. Recently KTS Korf Tecnologia Siderurgica, a division of Mannesmann Demag Ltda in Brazil, has developed a mini sinter plant for which the investment is compatible with small blast furnaces. Consequently, it is of great interest to evaluate the economical impact of using sinter in such small-scale integrated steel plants. In order to compare two alternatives, ie 100 per cent ore and 70 per cent sinter in the blast furnace burden, mass and heat balances for the entire operation from sinter plant through the blast furnace and EOF-based melting shop, were performed to evaluate the final production cost of the liquid steel. It was found that, depending on the sinter feed price, substantial savings can be obtained with the use of sinter.

Jan 1, 1999

The term slag has been used to define a wide variety of material including mine spoil and slag produced at steel plants. The present paper is concerned only with the non-metallic alumino-silicates developed simultaneously with iron in blast furnaces.The control of iron quality by slag has long been appreciated but here aspects of slag control based on concurrent iron production are indicated. Consideration is given to the basic composition of slags relative to the type of allotrope required. Up to a point, the plant conditions, under which a particular slag type is processed, have some effect, but these conditions only widen the range of a given allotrope.They do not convert one slag type into another. The nature of the slag types and experiments with additives to convert one slag type into another are discussed.The various uses for allotropes of blast furnace slag are considered.Their use in air cooled slag, foamed slag, slag wool, cements, soil stabilization, glass bottles, and building bricks and blocks, is explored in some detail.INTRODUCTIONWithin recent memory, blast furnace practice has been solely concerned with the production of iron. The slag make at this time had not reached embarrassing proportions. In Britain, unlike Germany, no legislation existed to prevent the growth of unsightly slag banks. Generally slag found limited use as fill and road material in the immediate plant vicinity. This is broadly the case in Australia today. In Europe and America, where the slag make is of the order of several million tons annually, the room problem and the cost of dumping slag has stimulated commercial and scientific research on the disposal problem. Currently, most iron plants in Europe can profitably dispose of at least 95 per cent of their slag make.

Jan 1, 1964

By D R. Cohen

As one of the four basic sciences, the study of geology is intrinsically worthy as a means of increasing fundamental knowledge of the behaviour and evolution of the universe. Geological knowledge can also be translated into practical outcomes for society such as resource discovery and protection of the environment. Australia has a long tradition of providing very high quality geoscience programs to prepare graduates for a range of occupations. We are, however, reaching a nexus in the way universities should or can deliver engaging programs. This has been triggered by the rapid evolution of the digital world (the Internet of Things), new technologies, unprecedented access to information, better understanding of the processes by which we learn and adapt our thinking, growing complexity in the problems we must face or opportunities to grasp, and university funding models. Designing education programs for the next generation of geologists extends far beyond tinkering with syllabuses. We must develop skills sets that will allow graduates to work in rapidly changing landscapes, but in doing so may have to sacrifice content to build capability in our graduates. Whereas universities must respond to changing demands on graduates by ensuring degree programs contain an appropriate balance of material and high quality of delivery, industry and government must also fulfil their responsibilities to provide additional training programs for graduates to assist their rapid transition into independent professionals. This paper examines various educational issues being considered in developing the new Decadal Plan for the Earth Sciences, and reflects on directions that education is heading in many of our universities.CITATION:Cohen, D R, 2017. Educating the next generation of geologists, in Proceedings Tenth International Mining Geology Conference 2017, pp 3–10 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By G J. Corbett, T M. Leach

Although hosted within an Ordovician magmatic arc, the Peak Hill high sulphidation system displays features typical of youngerPacific Rim high sulphidation epithermal gold deposits. Regional NW trending transfer structures are inferred to localise the magmatic source at their intersection of the NS trending arc. Fluids have migrated from the magmatic source along NW structures and thence exploited permeable horizons, which have become silicified. Alteration displays typical zonation from silicification through assemblages characterised by alunite, pyrophyllite and kaolinite and is followed by breccia/fracture controlled sulphide and gold deposition. Sinistral rotation on the NS arc has dilated NW trending fractures to produce the WNW to EW dilational fractures which host the higher grade ore. Mineral assemblages are typical of formation distal to the magmatic source in an epithermal environment. The combination of alteration and mineralisation zonation with structure provide fluid vectors which target a magmatic source to the SE of Peak Hill.

Jan 1, 1995

By Hargraves A. J

The paper outlines events at the Collinsville State Coal Mine, Queensland, leading to the practice of full face multiple shotfiring in bord and pillar development places. The 1954 disaster is referred to, and factors involved in simultaneous shotfiring in coal are discussed. Promising preliminary multiple shotfiring tests at the Colliery are described, as well as the resulting routine measures adopted, and the changes involved. The subsequent inducing of two outbursts under safe conditions by remote multiple shotfiring is given as justification for the changes made.INTRODUCTIONFollowing a disastrous instantaneous outburst (1.0.) of coal and gas at the Collinsville State Coal Mine in 1954, the necessity for inducer shotfiring for the control of possible further outbursts was established. However this mine, immediately classified as gassy after the 1954 outburst, is subject to the general restrictions pertaining to gassy mines which at present preclude the use of inducer shotfiring due particularly to the non-existence of a permitted exploder for more than six shots, and further, because permitted multipleexploders are not designed for remote firing through long lengths of cable. This situation was met by arresting or reducing progress in the production places, thereby reducing the danger of outbursts while means were being considered to achieve overall maximum safety.In August 1957 two full faces were successfully blasted in experimental simultaneous rounds. In June 1958 four full faces were blasted, and in October 1958 full face grunching without prior cutting, Le. inducer shotfiring, was introduced in No. 1 Tunnel as a production feature. In March 1960 it...

Jan 1, 1960

By Finlayson EJ

Epithermal gold is hosted by late Middle Miocene Okiduse Volcanics on Woodlark Island. Dating of associated alteration minerals indicate mineralisation to be broadly contemporaneous with volcanism (12.2 - 12.5 m.y.) and is probably related to subduction of the Solomon Sea plate along the Trobriand Trench. Mineralisation is polymetallic and structurally controlled. Pyrite, sphalerite, galena and minor chalcopyrite occur in steeply dipping fracture zones and/or hydrothermal breccia bodies associated with mixed clay-pyrite alteration envelopes. These envelopes occur within a terrane of regionally propylitised high-K, calc-alkaline andesites and related epizonal subvolcanics. Gangue minerals include quartz, calcite, dolomite and minor anhydrite. High level advanced argillic alteration and siliceous cap rocks are not present but may have been eroded off the top of the system. Fluid inclusion and stable isotope data suggest that the carbonates and paragenetically associated auriferous base metal sulphides probably deposited from an isotopically evolved (+8%. 180) reduced hydrothermal fluid sourced from underlying sedimentary rocks. The fluid was predominantly of low salinity (0-4 wt % NaCl equivalent) and had a temperature of about 270¦C at the time of boiling and mineral deposition.

Jan 1, 1987

Delhi Australian Petroleum Ltd., acting as operator for the joint interests of Delhi and Santos Ltd., has been engaged in petroleum exploration in the western Great Artesian Basin since 1958.Extensive airborne magnetometer, gravity meter, reflection and refraction seisomograph, and surface geological surveys have been carried out. Results of the surveys have considerably altered the concepts of the geology of the area.Seven exploratory wells have been drilled in the area. Results of the drilling have established the presence in the subsurface of previously unknown Paleozoic sediments which are capable of generating hydrocarbons.Production of oil or gas has not been achieved, but each phase of the exploration programme has resulted in progressively establishing the basic conditions necessary for the discovery of commercially profitable accumulations.INTRODUCTIONDelhi Australian Petroleum Ltd. commenced operations in Australia in 1958. They have subsequently been engaged in systematic exploration for oil and gas, acting as operator for their partner, Santos Limited. The methods and techniques employed are those used throughout the petroleum industry. The results of the exploration programme contribute to a better understanding of the basic geology, and concomitantly a firmer analysis of the petroleum producing potential, of the western Great Artesian Basin.Each phase has progressively enhanced the gross geological interpretation of the area with regard to favourable conditions for the generation and accumulation of hydrocarbons, but the stage has not been reached where productive potential is definitely established.Exploration status in 1958Basin configurationIn 1958 knowledge of the pre-Jurassic stratigraphy of the geographically defined western Great Artesian Basin...

Jan 1, 1964

The New South Wales coal industry is a highly mechanised well organised industry which has developed from an annual production of slightly less than 13 million tons in 1950 to over 33 million tons in 1969. Although continuous miners were not introduced into the mines until 1950, by Jillle 1969 the percentage of coal won by these units was 87.3. The paper describes mining conditions in the various coalfields of the State, their complexities and problems and how these have been dealt with. The introduction of fully mechanised long wall faces has presented a challenge which has been accepted and descriptions of systems in use are discussed. Major expansion of the industry is anticipated to meet the requirements of the growing Australian steel industry, for local power generation and to meet the increasing demands of overseas markets.

Jan 1, 1971

Electrochemistry Measurement, Using Chena Analyser, to Investigate Selective Separation of Pentlandite and Pyrrhotite

Sep 13, 2010

By G Eastwood, C Joyce, P Ryan, G M. Johnston

Over the years, predictive techniques for Acid Mine Drainage (AMD) and the natural processes affecting acid generation have received considerable attention. Less emphasis has been placed on the sampling strategy and the integration of testwork results with the geological data base. The sampling strategy employed and the development of a geological model to determine the spatial distribution and volume of acid producing material are often crucial for developing cost-effective containment and mitigation measures. The geological model provides a link between the occurrence, timing, destination and placement of mined waste rock. Careful and accurate interrogation of a comprehensive geological database provides this linkage. The AMD testwork program at Cadia in NSW has been designed to identify the temporal selective handling requirements that will be required during operation. Sampling involved collection of representative combinations of all waste rock types identified within an extensive geological database. These samples were subjected to static, kinetic and accelerated weathering predictive tests. Preliminary results have been used to construct a waste block model for the deposit that identifies the quantity and distribution of acid producing material. Integration of the block model with the mine scheduling determines when the material will be mined.

Jan 1, 1996

Nowadays, technology has improved to extract dimensional stone blocks at quarry sites and also to process these at processing plants for making slabs and tiles. In the process of quarrying and processing, performance evaluation of machinery is very important to achieve optimum output at minimum cost with improved technology. Cost analysis of improved technology includes parameters such as manpower, energy consumption, tool consumption, depreciation, maintenance and also others. The chainsaw machine with long boom and rail in marble quarries and multi-diamond wire saw machine for slab making from granite blocks at processing plants have recently been introduced in India. Thus, a study was carried out under a research project on these machines to assess their suitability. In this paper, performance evaluation and cost analysis of chainsaw and multi-diamond wire saw have been carried out with existing machines on the basis of research findings.

Dec 6, 2010

By H Susanto, N Belluz, D Flint, A Edw

The Deep Ore Zone (DOZ) is a block cave mining operation exploiting a diluted reserve of 131 million tonnes grading 1.06 per cent copper and 0.81 g/t gold in the lower portion of the Ertsberg East Skarn System (EESS). The EESS is a calcium-magnesium silicate skarn containing in excess of 250 million tonnes of copper-gold ore, located in the Ertsberg Mining District on the crest of the Jawawijaya mountain range in the highlands of Irian Jaya, Indonesia. The EESS was discovered in 1968 where it cropped out at an elevation of 4050 metres above sea level. The Ertsberg Mining District is underlain by siliclastic carbonate and siltstone formations of Jurassic to Tertiary age. The sediments have been folded and are cut by major bedding subparallel and crosscutting structures. Intrusion of a series of igneous bodies post-dates folding and faulting. These I-type intrusions are the source for the copper-gold mineralisation found in the Ertsberg Mining District. The EESS is hosted by carbonates of the Tertiary Waripi and Faumai Formations that have been altered to calcium-magnesium silicate skarn and is situated on the southern limb of a northwest-trending syncline. The EESS is an essentially vertical tabular body with a vertical extent of at least 1200 metres and a lateral extent of up to 1000 metres. The width of the EESS averages 200 metres and locally is in excess of 300 metres. The northeast (hangingwall) contact of the EESS is a skarn reaction front in sudden contact with barren marbles. This contact coincides with a zone of localised faulting and brecciation. The EESS is bounded to the southwest (footwall) by the Ertsberg Diorite, a 3.25 Ma old intrusive. The DOZ block cave operation extends from 3040 metres above sea level to a maximum of 3388 metres above sea level, has a length of 860 metres and a maximum width of 350 metres. The DOZ is a high temperature skarn with a prograde forsterite/diopside mineralogy whose protolith is the dolomitic Tertiary Waripi Formation. The principal retrograde alteration minerals include tremolite, actinolite, serpentine, talc and chlorite. Grade is highest where bornite occurs in large dense complex intergrowths with magnetite and anhydrite. Grade has been locally enhanced in the DOZ by a late-stage pyrite-chalcopyrite hydrothermal alteration event with associated brecciation. Ertsberg Diorite along the footwall of the skarn is also included in the reserve where it is mineralised endoskarn or has been mineralised by porphyrytic or late stage hydrothermal alteration. Formation of the EESS was initiated by contact metamorphism during the intrusion of the Ertsberg Diorite with later metasomatic alteration during both prograde and retrograde phases. The bulk of sulphide mineralisation formed late in the retrograde phase. The EESS is open along strike to the northwest and down-dip with on-going exploration of these areas. Current exploration is targeting both endoskarn and porphyry style alteration and mineralisation of the Ertsberg Diorite.

Jan 1, 1999

The effect of conditioning energy input on the metallurgical results of an emulsion flotation process has beenattributed by previous authors to a detergency process.This paper shows that such a process does not explain the data and that an attrition mechanism is more appropriate.

Jan 1, 1970