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By C Morley, B Costello

In 2002 the Argyle Diamond Mine upgraded the process plantÆs recrush circuit to include a High Pressure Grinding Roll (HPGR), or High Pressure Rolls Crushers (HPRC) as they are termed in the diamond industry. HPGR have generated considerable interest over the last decade, though there are still technical/processing unknowns to its effectiveness as a primary diamond ore crusher.The upgrade of the Recrush circuit at Argyle Diamonds has gone a long way to answering some of the key questions, and thus it has reduced the unknowns to a level more acceptable to the industry.This paper focuses on the results from the HPRC at Argyle, in particular the performance of the studded wear surfaces, comparison of energy efficiency against traditional quaternary cone crushers and the resultant increased liberation. Issues that have arisen, including edge wear of the studded surfaces, will be discussed and the steps taken to reduce this issue are presented.

Jan 1, 2004

By Large RR

Precious metals in the Rosebery north-end orebody occur predominantly in sphalerite- galena-pyrite ore and to a lesser extent in massive barite mineralisation. Gold may also occur in the upper parts of pyrite-chalcopyrite ore (although this ore type is usually gold poor), in pyritic mineralisation lateral to base metal sulphide lenses and in the footwall (very patchy). Although present, remobilised precious metals do not occur in economically significant quantities. Mineralogically, silver occurs dominantly in tetrahedrite and, to a lesser extent, argen- tiferous galena. Gold occurs as electrum associated dominantly with pyrite and, to a lesser extent, tetrahedrite. Geochemical modelling suggests that silver was probably transported as a chlorocomplex, while gold was transported dominantly as a thiocomplex, although at high temperature gold was transported as a chlorocomplex.

Jan 1, 1987

Whereas traditionally, stable isotope research has been directed towards resource exploration and development, it is finding more frequentapplications in helping to assess the impacts of resource utilization upon ecosystems. Among the many pursuits, two themes are evident:(1) tracing the transport and conversions of pollutants in the environment and(2) better understanding of the interplay among environmental receptors, e.g. food web studies. Stable isotope data are used primarily to identify the presence of pollutants in the environment and with a few exceptions, the consequence of their presence must be assessed by other techniques. Increasing attention has been given to the isotopic composition of humans with many potential applications in areas such as paleodiets, medicine, and criminology. In this brief overview examples are used from the Pacific Rim to illustrate the above concepts. Stable isotope data will undoubtedly play an increasing role in multi-disciplinary research in the Pacific Rim. However, consideration should be given to more effective strategies, e.g. networking, for pursuing large scale problems such as long range circulation of pollutants.

Jan 1, 1990

By Callaghan R. P

Underground production from the low grade copper orebodies at Mount Lyell in recent years has involved surface subsidence of open cut areas. Relevant structural and lithological features of the geological environment are des- cribed. The highly mechanised underground mining system involves sublevel caving and sub- level open stoping with associated hangingwall cave. Monitoring of subsidence and caving has been made by regular visual inspection and measurement of crack development, and by sur- face profile surveys. These simple techniques have proved adequate in assuring management that ground movement is proceeding normally and safely.

Jan 1, 1980

Various aspects concerning gold are mentioned below. These have no common theme but suggest points of interest any one of which, if warranted, could lead to development later and elsewhere. 'High level' auriferous gravels The gold deposits of Victoria are commonly classified as being either primary or secondary. Most primary occurrences comprise gold present in quartz reefs, together with other lode-like occurrences in which gold is associated with various sulphides, with or without quartz. Secondary occurrences are derived by physical release of primary gold and subsequent concen- tration of it as a constituent of sediments. Secondary gold deposits may be themselves eroded so leading to third or even fourth generation gold.

Jan 1, 1982

By D J. Brake

In most underground mines, the ventilation system is a significant portion of the total mine capital and operating cost and the largest consumer of underground electrical power. The effectiveness of the ventilation system has a major bearing on the safety, health, comfort and morale of underground personnel, and has a critical role in meeting production targets and therefore business revenue. Perhaps the most important component of the primary ventilation system is the primary fan. Correct performance testing of the primary fan during the warranty period is important not only to ensure the mine has obtained the asset that it paid for and can therefore deliver on the fanÆs crucial safety and economic role in the future of the mine, and to provide a justification for releasing final performance warranty payments to the supplier, but also to provide a benchmark or baseline against which to assess future performance issues. As there are at least three potential international standards available to measure fan performance, there has been considerable confusion regarding which of these to use for testing primary mine fans, and also the correct allowances and tolerances to use. This paper provides guidance on which standards to use for different applications, how the standards should be interpreted, what allowances and tolerances are reasonable, and other important issues to be resolved with the fan supplier prior to making a contract award. The paper also discusses practical issues and methodology for in situ primary fan performance testing.CITATION:Brake, D J, 2013. Performance and acceptance testing of main mine ventilation fans, in Proceedings The Australian Mine Ventilation Conference , pp 141-148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

The phosphatic overburden of Christmas Island is a lateritic soil and consists dominantly of crandallite and millisite. These minerals are polymorphs of general formula, (Na,K)x Ca2-x (Al, Fe)6 (PO4)4 (OH)10-x (2+x) H2O. Iron occurs only in millisite. Both minerals exhibit similar thermal transformations, dehydroxylating near 600¦C and recrystallizing above 800¦C. Dehydroxylation results in crystal structure collapse but retention of crystal morphology. Ggethite, boehmite and apatite are minor constituents of some-of the phosphatic Soils.

Jan 1, 1971

By Reeves I. And Farquhar J, Pearce S

The irregular shape of the Rosebery orebody, coupled with the inconsistencies in grade over short strike lengths, has meant stoping blocks have had to be small to combat dilution and stability problems. In the past, each lens was divided into regular block sizes and developed up to five years before production commenced. There were two major drawbacks to this practice; firstly, existing development deteriorated over time therefore requiring rehabilitation prior to production. Secondly, the pre-determined blocks could not be easily changed to incorporate changes in mining technology or economic circumstances. Bearing these problems in mind, it was evident that any new lens development had to be designed to allow maximum flexibility. The lens being currently developed is J lens. It represents approximately 50 per cent of the current reserves tonnes, and 65 per cent of the zinc metal. Its importance to the mine's future cannot be over emphasised. At its core the lens is up to 25 m thick at grades of over 30 per cent zinc. The practice of dividing the orebody into levels and sublevels, with consequent crowns was no longer acceptable because of restrictions in stope design and potential loss of ore. To assist in the development planning of J lens, a geostatistical block model was applied in long section to graphically represent the lens. Areas of high zinc concentration, as well as zones of uneconomic material were identified by using the model. This has meant that the development could he targeted, enabling stope delineation to occur in the lens without significant ore loss. Because of limited development resources, and the need to bring J lens on-line in the near future, the development strategy has had to focus on 'just-in-time' principles, rather than accessing the whole lens from bottom, and progressing upwards. Tight development schedules have required individual stoping block to be developed on such factors as grade and available tonnes rather than as a vertical sequence.

Jan 1, 1993

A co-operative research project, combining Commonwealth Scientific and Industrial Research Organisation (CSIRO) research scientists findings and company iron ore geologists' expertise, resulted in new concepts about the origins, distribution and complexitie of iron ores and their parent rocks (banded iron-formation or BIF) in the Hamersley Iron Province of Western Australia. Understanding these problems was important to the efficiency of exploration, development and ultimate mining of iron ores. This genetic model, based on a detailed mineralogic background, was modified by Mt Newman geologists to obtain a user oriented classification for practical application in the field.The proposed Pilbara Iron Ore Classification (PIOC) gives iron ore geologists a basis from which to understand, identify and record the various mineralogic and physical characteristics of the many genetically different ore types occurring within and between orebodies in the Pilbara. More definitive quality control over ore products can be achieved based on the detailed understanding of ore types which the PIOC allows, compared to current classifications which deal only with the physical nature of ores. Of equal importance, the classification remains sufficiently simple to enable owners, operators and buyers to achieve a basic appreciation of ore type variations.With little modification, it is believed the classification has applications beyond the Pilbara, to iron ore worldwide.

Jan 1, 1984

By K George

The Dugald River lead-zinc-silver deposit is located approximately 60 km north-west of Cloncurry and 87 km north-east of Mount Isa. The development project is expected to turn operational in 2018. The resource is estimated to contain 61.1 Mt at 12.6 per cent zinc, 1.9 per cent lead and 34 g/t silver, with a projected mine life of 25 years. The evolution from exploration project to development project has presented multiple challenges for the technical team. Understanding and modelling the structural complexity of the deposit has been one of these challenges.Historically fault zones were logged as a lithology, with structural measurements recorded in a separate database table. When underground drill programs and development commenced in late 2012, it was recognised the deposit was more structurally complex than had been modelled. The extensive number of fault zone lithologies in core logging, made it difficult to identify fault trends and model faults in 3D software packages.In 2014, a structural project was conducted to produce a fault model for the deposit. The project highlighted that by logging the faults as a lithology, a shortage of fault characteristics was being recorded. Additionally, structural information could not be filtered to identify different fault sets due to the lack of information available to filter on. One of the major outcomes of the study was to change the methodology for the structural logging of drill core.Faults are now logged in a separate structural log. The structural log collects two types of information: interval data and point data. The interval data represents the damage zone of the fault in the surrounding rock and the point data the plane of movement for the fault. The faults are further characterised by their intensity on a scale of one to five, the type of fault structure (fault breccia, fault vein etc), the minerals present on the fault surface and structural measurements when available.The new data set allows fault data to be filtered based on fault characteristics, making implicit and explicit modelling of the faults more timely and accurate. The data set can be used to produce fault wireframes as single surfaces from the point data or hanging wall and footwall surfaces from the interval data. The logging method and how its applied in fault modelling form the focus of this paper.CITATION:George, K, 2017. A new approach to logging and modelling faults at the Dugald River Pb-Zn-Ag deposit, North West Queensland, in Proceedings Tenth International Mining Geology Conference 2017, pp 315–320 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

A simple production technique has been initiated and implemented at Oaky Creek open cut coal mine to optimise recovery of coal from the relatively thin geological seams. The production technique is based upon minimising coal dilution through careful dragline operation and the selective use of mine mobile equipment to clean the top of coal. In addition, recovery of coal from the pits has been increased by refining blasting and dragline methods.The implementation of the recovery optimisation programme at Oaky Creek has provided significant economic benefits from increased yield through the preparation plant by the reduction in dilution, and from increased raw coal tonnage through improved pit recovery methods.

Jan 1, 1990

By Frew J. A, Harris M. C, Manlapig E. V

The recovery achieved in a flotation process is a function of both the characteristics of the feed stream and the operating conditions within the flotation cell. In this paper, the flotation characteristics of the streams within the Red Dog le

Jan 1, 1997

By Wood P. D, Pettifer G. R

In the upper coal surface in the Latrobe Valley, craters known locally as fireholes have developed due to prehistoric coal fires. They can be several hundred metres across and up to fifty metres deep, and are now filled with overburden materials varying from hard baked clays to very soft lacustrine clays. In addition to reducing coal reserves, continuous mining operations are seriously affected by fireholes. Large undulations in the upper coal surface result in a mixture of coal and overburden on the upper mining levels. The very soft lacustrine clays are unstable in the mine batters and the overburden dump, are difficult to handle on the bucket wheel excavator/conveyer system, and have insufficient bearing capacity for the large bucket wheel excavators. Early identification is essen- tial and both drilling and dynamic core penetrometer have been exten- sively used. However, this has not proved adequate in locating and defining the extent of all fireholes, due largely to their irregular shape. To overcome this a range of geophysical techniques has been trialled with very promising results. A trial area has been covered on a twenty metre grid using gravity and Geonics EM34 conductivity measurements and the same area has been covered at a closer spacing with high resolution magnetics. Image processing of contoured magnetic, EM34 conductivity and residual gravity data has resulted in very good correlation with drilling data.

Jan 1, 1989

I am honoured and very pleased to have been given the opportunity this evening to say a few words of thanks not only on behalf of all the guests but especially for the delegates and accompanying persons attending the 13th Congress of the Council of Mining and Metallurgical Institutions. Firstly, I would like to congratulate Sir Hamilton Whyte,KCMG for his most interesting address. In his far ranging talk, when he showed knowledge of widely diverse subjects, I had a brief fear that he was going to be talking about the details of support methods in deep level mines, or how to avoid flotation problems in multi-metal mines. Although he did not go that far, he touched on subjects which have arisen this week - long term planning and secure supply of minerals at acceptable prices. The dire predictions of the Club of Rome have been debunked with a far more elastic supply of minerals having been proved. Combined with the importance of a falling birthrate in some parts of the world, this will lead to many changes in the future, when hopefully governments will take the long term view rather than look at the next budget or the next election. Maybe some of them are not too lazy to do this for all of us. However as a fellow Ukranian, I feel that he might have been called something different if he had been in Australia. Sir Hamilton, thank you for your talk. Once upon a time - and this is not a fairy story - there was a cobbler who had two sons; one very bright who became a professor of mathematics; the other, dim, who became a millionaire shoemaker. Asked for the secret of his success, the millionaire attributed it to a vital piece of economics which his father had imparted, "Be content with small margins on a large turnover." "So", said the millionaire, "I make my shoes for $2 a pair and sell them for $5. I am very happy with the three per cent profit."

Jan 1, 1986

By D Kepert

It is the role of the exploration geologist to create wealth through the discovery, delineation and characterisation of economic mineralisation. This requires a critical depth of geological understanding.Unfortunately, the resource industry is well known for its cyclic nature. Many of the current generation of workers have only ever experienced the boom of the ‘super-cycle’ and are only just discovering the negative side to the business. For the case of the geologist and especially the exploration geologist, the magnitude of peaks and troughs are usually amplified and may become destructive to all parties. During the uptime a healthy stream of exploration good news becomes the staple diet of company releases, in particular those of junior companies attempting to bolster the share price. The geological knowledge and experience gained thus forms a significant and integral part of the value and therefore, future of a company. On the downturn it is often viewed that geologists are a luxury, an optional extra and a burden on the bottom line with companies entering a period of memory loss and myopia.Retention of geological knowledge however remains critical as projects, companies and cycles mature. Beyond exploration per se, this knowledge becomes both fundamental in de-risking and commercialising an asset (through development or divestment) and in positioning the company for cyclic or counter-cyclic opportunities.The growth and retention of this knowledge base is difficult to quantify in terms of direct value but becomes one of a successful resource companies greatest assets. At worst, its loss can lead to millions of investors’ funds wasted on missed opportunities, drilling, or poorly designed plant and mine.But the rocks are around for the longer haul and pay little notice to the vagaries of the scurrying of Man.This paper reflects on some of the authors own observations through 25 years of iron ore exploration, in why it is critical to always rigorously question the prevailing geological (mis)understanding and the technical and commercial benefits which that may bring, and looks forward to the future.CITATION:Kepert, D, 2015. Geology – the affirmative case, in Proceedings Iron Ore 2015, pp 285–298 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

Design of cemented fill in mining is often carried out without any consideration of the structure of the fill. The composition of cemented fills varies in the stopes due to the placement method, and the strength of the fill in the laboratory depends on the density, orient- ation, moisture content and drainage conditions. Within each stope there are definite zones and the structure of both cemented rockfill and cemented hydraulic fill has to be defined for each zone and the field conditions simulated in the laboratory. Structure also affects fill permeability and compressibility. From a study of the cemented fill in place, the effect of changes in the placement methods can be seen and then controlled to improve fill performance and economy. These features of cemented hydraulic fill and cemented rockfill behaviour are discus- sed and illustrated through reference to field and laboratory work undertaken at Mount Isa.

Jan 1, 1973

The following is based on two examples of emission control with coal fired power stations as practised in Germany at Heilbronn Block 7 power station and the Rheinbraun coal combined power station with integrated high-temperature Winkler system (HTW). Heilbronn Block 7 demonstrates the successful emission control of sulphur and nitrogen oxides and the (HTW) system the reduction of the specific carbon dioxide emission. Both were sparked off by legislation which demanded certain emission control standards. Since the early eighties environment protection has been a matter of heated public debate in the European Community. A recent survey in Germany showed unemployment as being the only subject matter more frequently in the minds of people than environment protection. A new kind of forest devastation in areas away from industry has caused investigations by several government departments and private enterprise. Because of lack of conclusive evidence so far, the principle of PRECAUTION has replaced the CONCLUSIVE evidence as a base for new legislation concerning the environment. The new legislative standards for nitrogen oxide emissions in Germany for example have reduced NOx emissions of power stations from 1000 mg NOx per cubic metre of flue gas in the beginning of 1983 to 200 mg NOx per cubic metre of flue gas in April 1984. These new standards were enshrined in legislation when research provided some evidence linking nitrogen oxide emissions through photo-chemical reactions with forest devastation. Thirty European countries signed a treaty in 1983 expressing their concern about air pollution and their willingness to co-operate with each other in controlling large scale emissions.

Jan 1, 1991

Mineral sands are different to almost any other commodity; however, it shares similarities with other commodity types, such as the importance of quality constraints of iron ore and coal or the importance of physical properties of diamonds. The mineral sands industry consists of two principal product streams; titanium dioxide minerals û in the form of rutile, ilmenite and leucoxene, and zircon. The principal valuable heavy minerals (VHM) include ilmenite, leucoxene, rutile and zircon. Variations of other titanium minerals occur between the end members of ilmenite and rutile, including pseudo rutile and anatase. Most mineral sands deposits are found in unconsolidated fossil shorelines several hundreds of metres to tens of kilometres and occasionally hundreds of kilometres inland from the present coastline. Mineral sands orebodies essentially fall into two categories based on the mode of deposition: alluvial or aeolian. Alluvial deposits are further split into marine beach placers (or strandlines) and lacustrine heavy mineral (HM) accumulations. Exploration for mineral sands involves the positive identification of key criteria leading to the focus of exploratory surface sampling, augering and drilling. Assaying is primarily focused around determining the percentage of HM contained within a given sample. Other results of interest include clay fines, sand and oversize. Metallurgical/mineralogical assessment is often undertaken via laboratory scale bench tests that replicate the wet concentration and dry mill processing routes. The most critical component in resource assessment for mineral sands is about quantifying HM grade, then mineralogical assemblage and then quality of those mineral species. This will determine whether a mineral sand final product is marketable or not. Mining of mineral sands is conducted either wet or dry. Wet methods are generally preferred for large tonnage, unconsolidated and low clay orebodies. Where ground conditions are hard and orebodies are small, high grade and discontinuous, dry mining techniques are generally employed. Concentration of mineral sands from the primary ore is carried out in two sections; wet, utilising sizing and gravity differentiation between HM, VHM, clay and quartz, and dry, exploiting the magnetic, electrostatic and to a lesser extent specific gravity (SG) properties of the minerals of interest. Mineral sands exploration, mining and processing faces the same operating challenges as the rest of the resource sector. Added to this are the issues that are unique to mineral sands and to which the industry devotes considerable resources to developing solutions.

Jan 1, 2009

By Wood CJ, Davis JJ, Askew H

A dynamic model of a dense medium circuit has been developed and tested against plant data. The model shows the response of the circuit to both controlled (changes in specific gravity set point or changes in circuit coal feed rate) and uncontrolled changes (changes in raw coal moisture, loss of raw coal feed) in operating conditions. The model is built up from dynamic models of the individual sumps, pumps, pipes, splitters, magnetic separators and automatic controllers in the circuit. The model can be used for design of automatic control loops and for investigation of possible process modifications such as changes in water addition points. This paper describes the model construction, the testing of the model against actual plant data and gives some examples of its use in investigating plant response to changes in operating conditions.

Jan 1, 1978

DURING the four years, 1922, 1923, 1924, and 1925, China produced the following quantities of non-ferrous metals and ores: Antimony Products - 67,869 (long) tons. The production for 1925 was 20,869 tons, of which 80% was regulus, 14% crude,and 6% oxide.Arsenic (White) - 4200 tons. The production for 1925 was 1200 tons, but only 90 tons were exported, some 25% of which to Hong-Kong, France, and U.S.A. each, and the rest in small lots to other countries. Domestic consumption was 1110 tons, and thelocal price for "cake" was around £47 per ton on 1925 exchange.Arsenic Ore (Realgar) - 1400 tons.Lead Ore (Galena) - 44,853 tons. The production for 1925 was 10,853 tons, of which 16%, produced in Korea, went to Japan, and 84% produced in Hunan, went to Europe.Manganese Ore (Pyrolusite) - 142,567 tons. The production for 1925 was 42,567 tons, of which 94.3% went to Japan.Tin Ingot - 33,480 tons. In 1925 the exports to Hong-Kong were 8880 tons of usual rough tin of 94% to 96%. Most of this was refined to No. I Chinese quality of 99.3% and exported to U.S.A. and Europe, owing to the good price ruling.Sulphur - 12,000 tons. Sulphur is included in this list in order to explain how its production led to the discovery of some other ores.Wolfram - 19,668 tons. The production in 1925 was 5868 tons, most of which came from the Quee Mee mountain district in South Kiangsi, from the detrital deposits. Civil disturbances prevented the usual output from Hunan border.Zinc Ore (Blende) - 134,190 tons. Exports for 1925 were 34,190 tons of low-grade ore, averaging 30% zinc, 14% lead, and 7% silver...

Jan 1, 1927