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Simulation and Analysis of Media Behaviour in the Tower Mill by Discrete Element Method for Estimating the Power Draw and Spatial Distribution of Grinding Process The trends to the Tower Mill (TM) for grinding the materials are increased recently due to its unique merits. Among the various considerations of this machine, the main important items are increasing the efficiency of grinding as more as possible while keep the power consumption, manufacturing and maintenance costs as less as possible. Because this grinding process includes a huge numbers of media particles (ball or other shapes) that are interacted with each other and body of the machine, the DEM (Discrete Element Method) way is a very useful and essential step to getting confident evaluations. Because the DEM simulation is a very young scientific field and proper commercial software are very rare and still under modification, at first step, a FORTRAN code is developed for DEM simulation of two laboratory Tower Mill models (KM5 and KD5). The simulation and experimental results matched each other properly. Then one another DEM software was implemented to perform simulation of bigger models (huge numbers of balls), meanwhile could handle the complex 3D geometry data. The simulation and experimental results were compared and analysed in detail for not only laboratory but also for industrial models (KW5, KWD5, KWD50, KW300F, KW700F and KW1500) without any manipulation or compromising of the parameters of simulation. Some numeric data of industrial models are hidden here due to confidential reasons. The relative velocity of balls (ball-ball and ball-TM body), dissipate energy, interacted forces and stresses during the process are the key outputs of DEM simulation for design this machine. Therefore the main important processes in a Tower Mill machine are recognised and consequently some horizons of development of this machine are distinguished.

Sep 13, 2010

By Beevers J

The Ok Tedi Project is now a high production open-pit porphyry copper mine located in the Star Mountains of Papua New Guinea (PNG). At present, total daily production is 190 000t of ore and waste. Large scale drilling and blasting has only been in operation since 1988, prior to which all material was removed by ripping and dozing. This paper reviews the steps taken over the last 12 months in establishing a more efficient drilling and blasting operation and highlights the significant reduction in powder factor. These improvements have been achieved largely through the introduction of air-bags, controlled pattern expansion and an overall focusing on the operation by involving consultants, ICI's technical service and internal departments.

Jan 1, 1991

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

Jan 1, 2007

The placer mining industry of the West Coast region of the South Island is based largely around the production of alluvial gold, although other valuable minerals are also present. Since the first major discoveries in 1864-65, reported gold production has totalled around 264 t (8.5 Moz). During the past 10 years, annual production has totalled around 1460 kg (47,000 oz). It is anticipated that gold production over the next three years will continue at a level of 1400-1800 kg.   Annual gold production peaked during 1866 at approximately 17,170 kg (550,000 oz) and has not exceeded 100,000 oz since 1885. This reflects the ease with which gold was won from shallow, rich deposits that were present at many localities. Subsequently, there has been a general decline in the availability of this type of deposit, a trend that will continue in the future. This paper outlines the present state of placer mining in the West Coast region, gives some historical background to the industry and briefly predicts future trends.

Jan 1, 1997

By D Fergusson, J D. St George

Highwall stability is a major consideration in optimising opencast mine geometry. It involves assessing the risk of those slope failures that are large enough to have significant cost, safety and/or operational implications. These risks are then balanced against the value of the resource to arrive at an acceptable slope design. Load-deformation models (commonly referred to as ænumericalÆ models) of slopes provide a powerful tool in this decision-making process since they can be verified well before slope failure occurs. This gives the slope designer increased confidence in reviewing designs during excavation, potentially allowing early revision of pit geometry to either increase or decrease safety margins as appropriate. However, these models are not always adopted as they depend heavily on an appropriate choice of constitutive model and material parameters.   A preliminary load-deformation model of a 170m highwall in Solid Energy North (SEN) OperationsÆ Awaroa 4 opencast coal mine in the Rotowaro Coalfield has been prepared. This uses a strain-dependent constitutive model based on laboratory test results, strength parameters developed by SEN and excavation monitoring data. The laboratory testing has included triaxial compression tests on large-diameter fractured samples to characterise the stress-strain response of the closely-jointed soft rock masses that exist in many parts of the mine. Data from the monitoring of a 25m cut made during excavation of a haul road has been used to refine and verify the constitutive model. The resulting highwall model has predicted highwall crest movements corresponding to the excavation of each bench, for comparison with monitored values. Key model outputs are total horizontal movements of about 0.5m near the highwall crest and shear strains of 0.5-0.7% at the locations of potential bedding-parallel shear planes underlying the highwall. Most of the movement is expected to occur as creep rather than as an immediate response to excavation.

Jan 1, 2006

In a field test at Mount Isa Mines Ltd., a system developed by ICI Australia Ltd. for bulk loading "MOLANITE", an ammonium nitrate slurry blasting agent into ring drilled holes of wblcvel open stopes, was shown to be satisfactory. The fragmentation produced by the slurry was a significant improvement over ANFO and the stope production rate was increased by approximately 50%. Indications are that the charging rate and labour costs will not be greatly changed if a slurry system is used.

Jan 1, 1973

By D Preedy, J K. Claflin, S R. La Brooy

A gold mine in north-eastern Africa has expanded throughput from 5 to 10 Mt/y in recent years. The original carbon regeneration kiln was incapable of achieving required throughput or meeting process conditions to reactivate the carbon due to heavy fouling by high molecular weight frothers and collectors. A new high temperature kiln was required.The design criteria for the carbon reactivation kiln and associated equipment were revised, then implemented in close cooperation with a kiln vender who had previously supplied kilns operating successfully on highly fouled carbon. The result is a whole facility, holistically designed to achieve the technical criteria.The new carbon reactivation facility has been operating since 1 July 2014. What have we learned? What has performed to expectations? What could be done better?This paper presents lessons learnt regarding the design, implementation, operation and maintenance of the Ausenco Carbon Reactivation Kiln. ‘Lessons’ are associated with threats and opportunities (risks) that have that have been realised. The importance of identifying and managing risks for even small straightforward projects is demonstrated.CITATION:Claflin, J K, La Brooy, S R and Preedy, D, 2015. Lessons learnt and performance – installing and commissioning an Ausenco carbon reactivation kiln in Africa, in Proceedings MetPlant 2015, pp 163–174 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

The Illawarra District, from 50 to 100 miles south of Sydney, is one of the State's important coalfields. It extends from Clifton on the north, to the Shoalhaven river on the south, and from the coast westward beyond the coastal scarp.For descriptive purposes, this area falls naturally into two zones:(a) the coastal belt backed-by the eastern edge of the plateau;(b) the plateau, westerly from the coastal scarp.(a) The Coastal Belt.A triangular shaped area extending from Clifton to the Shoalhaven river, composed for the most part of soft coal measures strata of Permian age, which, on weathering, undermines the massive overlying Mesozoic sandstones and causes the gradual recession of thecliffs.South of Wollongong, upper marine sediments and contemporaneous igneous rocks make their appearance beneath the coal measure beds and occupy the greater portion of the coastal belt.(b) Plateau Area.Extending westerly from the coastal escarpment is a plateau known as the Robertson Tableland, composed of Triassic sandstone and shales dipping gently in a northerly direction, and capped in places by Wianamatta. shales and r.rertiary basalts. This tableland is approximately 2400 feet above sea level in the vicinity of Robertson, and gradually falls to about 750 feet at Waterfall.The plateau area for the most part is highly dissected, rough, steep gorges alternate with sharp ridges.A large part of the northern watershed of the Robertson tableland is a reserve for Sydney water supply, and large dams have been constructed at Cataract, Avon, Burke, and Cordeaux.

Jan 1, 1938

Despite a long history of production of industrial minerals and rocks, New South Wales still offers significant opportunities for exploration for and development of these minerals. Exploration for opal, sapphires, and zeolites in the State has been particularly encouraged by pioneering geological studies by the Department of Minerals and Energy, which have resulted in the development of important new geological concepts and exploration techniques. Large areas with potential for these minerals have not yet been tested. In the case of sapphires, the studies have identified a new type of deposit which is'the source of most of the sapphires mined from alluvial deposits. Recent price increases for heavy minerals, a re-evaluation of previous exploration in coastal regions, and a recognition of suitable environments in inland New South Wales have stimulated renewed exploration both onshore and offshore and have led to increased production. Significant potential also exists for development of a number of other minerals, including: topaz, which occurs in large, unusual and perhaps unique deposits in northern New South Wales; dimension stone (particularly granite); bentonite; diatomite; and silica for metallurgical use. Potential also exists for development of construction material resources, particularly construction sand, which is in short supply in the Sydney region.

Jan 1, 1989

By L Lachance, F Flament, D Leroux, S GariTpy

"Considerable metal values are often locked in stockpiles (ore, concentrates, heap leach pads, slags, reverts, etc.) and process equipment (bins, holding tanks, thickeners, etc.). This is more than enough to justify accurate accounting of such in-process metal inventories from both financial accounting and operational perspective. However, accurately determining the metal inventory of an in-process unit is often a challenge in industrial practice. Audits have shown that available indirect or direct measurements often carry large inaccuracies. Sooner or later, ignoring these measurement errors lead to unexpected incoherencies in reported metal balances. In such situations, coherent metal balances are then achieved through subjective and sometimes significant adjustments of in-process inventory levels. While such metal accounting methods applied by mineral processing engineers used to be rarely challenged, they are now being increasingly scrutinised by various stakeholders. Hence, metal accounting procedures that mitigate subjectivity in adjustments while still coping with the unavoidable uncertainty are more relevant than ever.This paper reviews three different metal accounting methods for reporting in-process metal inventory values. Their individual application strongly depends on the available measurements i.e. The indirect method where the metal inventory of a given process unit is determined by subtracting the cumulative reclaim from the cumulative feed carries important flaws. The direct method also comes with challenging accuracy issues so that emptying a process unit is often the best available inventory measurement. This reality is recognised for by further analysing a previously proposed operating mode where two interchangeable process units are alternately used. The third investigated method is the redundant method which combines indirect and direct methods for a given process unit. This paper reveals that the dual process unit operating mode and the redundant method can both significantly improve the estimation quality of in-process metal inventories.CITATION:Lachance, L, GariTpy, S, Leroux, D and Flament, F, 2013. Review of metal accounting methods for in-process metal inventories, in Proceedings MetPlant 2013, pp 102-117 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jul 15, 2013

Determination of Flotation Kinetics of Coal Grain Types in a Pilot Scale Jameson Cell using Coal Grain Analysis Method

Sep 13, 2010

About 15 per cent of total electricity (400 MkW) was generated by nuclear power plants in the world (2009) and about 36 000 tons of uranium has been mined in uranium mines annually. Radioactive waste material is produced from uranium mines and nuclear power plants. The wastes must be disposed or stored safely for long-term. If they leak and/or move from disposal or storage sites due to air/groundwater flow, then a serious environmental pollution can occur. Hence, multi-layer system has been proposed and employed in order to seal off these radioactive waste materials from biosphere. Basically, bentonite is now used for establishing absorbing and sealing layers in this system. However, the amount of high quality betonite is very limited and in some cases it is hard to be obtained.On the other hand, a great deal of refuse from coal burning plants is produced every year and the amount of it is expected to be higher each year, especially in developing countries. More than half of flyash is utilised and the remaining is disposed at the disposal sites. However, the life of the disposal site is limited and it is diff cult to find a new disposal site. It is requested that the percentage of the utilisation of the flyash be increased in every field.From the above two points of view, a flyash-based barrier layer/cover system is considered in this research and this paper discusses the applicability of flyash as a content of barrier layer/cover material based on the results of a series of laboratory tests.

Dec 6, 2010

By Tyler R. J

Methylene blue dye adsorbs on chalcopyrite concentrates slurried in aqueous solution. Saturation adsorption can be achieved within about 24 hours for dye equilibrium concentrations greater than about 10-5 M. The dsorption coverage is obtained from a measurement of the' colour change of the solution. Comparison with BET measurement of the concentrate surface area shows that 2.4 ± 0.1 µmol of methylene blue are adsorbed per square metre of surface accessible to the dye cation. The procedure described can be used as a single-point measurement and values for the surface area can be otained to within about 10 per cent with inexpensive instrumentation.

Jan 1, 1979

The rush for alternate iron-units in the last few years spurred a true outbreak of new alternate iron units projects many of them incorporating new process in what can be classified as the.most fruitful and innovative technology outburst, in the steel industry, in decades In a recent paper we focused on what would be, in our opinion, the ultimate targets of the use of alternate iron-units by mini-mills: 1. to improve quality, 2. to reduce cost, 3. to increase plant productivity, and 4. to improve `supplyability'. With these objectives in mind liquid hot-metal, among all possible scrap substitutes, has been proven to be by far the best. This conclusion stems from many different authors who have reviewed the `value in use' of hot-metal against other alternate iron units and measured its impact on steel-shop productivity and cost (Figure 1).

Jan 1, 1999

By Gartrell H. W

During investigations of the treatment methods for ore from the Bird-in-Hand gold mine carried out at Kalgoorlie and at these laboratories, it was found that excess alkali caused a lowering of extraction by cyanide, the cause of this being attrIbuted to the presence of a small amount of oxidised lead compounds in the ore. The subject has been discussed by various writers,3 but no satisfactory explanation of existing facts has been put forward. The experiments described in this report have been carried out with the object of obtaining some insight into the chemical reactions underlying the effect of lead salts and alkalis in cyanidation.The formation of cyanide-insoluble coatings on gold during roasting with lead compounds is well known, but the adverse effect of alkalis in cyanidation of ore is *This paper represents work done under a co-operative agreement between the Commonwealth Council for Scientific and Industrial Research and the South Australian School of Mines and Industries.Published by permission of the Mining Advisory Committee, Commonwealth Council for Scientific and Industrial Research.

Jan 1, 1935

In a previous paper the writer dealt -with the jasper bar formations and their relationship to the structural geology of older pre-Cambrian rocks in the goldfields districts of Western Australia (24). He has pointed out in this ahd other papers that jasper bars, or banded iron formations, banded hematite or ,magnetite quartzites, jaspilites and related banded ferruginous or non-ferruginous cherts, occur in abundan'ce in the Older Greenstone Series of Western Australia (22), (24), (26). They are considered to represent special forms of banded ferruginous sediments, and are usually fpund in the field interbedded with more or less metamorphosed pasaltic 01' andesitic lavas and tuffs, now amphibolites, together with occasional thin bands of normal pelitic sediments, which go to make up a large proportion of the Older Greenstones in thfs State (26).Great thicknesses of fiat-bedded ]:landed ferruginous cherts are also found associated with cherty' carbonate rocks; quartzites, shales and thin-bedded dolomite whicIi constit'ute the Nullagine (Pl'oterozoic) system in the northwest of Western Australia. In the Hamersley Range district these banded ferruginous chert beds are the hosts of important deposits of blue amphibole asbestos.In the paper mentioned above brief reference was> made to the importance, of geological structure in relation to economic geology, particularly in the goldfields regions of Western Australia, and it was shown that jasper bars may have an important role in the study of 'the structural geology of many of these regions. Of possibly more immediate economic importance is the part that these rocks play, both directly and indirectly, as host rocks for mineral deposits-the chief of Which are gold, iron ores, blue asbestos, and manganese ores. The blue asbestos bearing banded iron formations mentioned above are confined to the younger pre-Cambrian Nullagine formations. They have been described in detail elsewhere (23). In this paper it is proposed to discuss the economic geology of the jasper bars found in the older pre-Cambrian series.The jasper 'bars have in themselves little or no intrinsic value except perhaps some of the more highly coloured and banded varieties which may be utilised for ornamental and decorative purposes. Probably the best known of such varieties is the so-called "marble bar;" a belt of, strikingly coloured banded chert occurring just south and west of the famous town of that name (see Fig. 1t). This consists of a hard, very fine, even-grained rock with alternate individual stripes varying from the thickness of a sheet of paper up to an inch or more in width, and ranging in colour from clear white to yellow, from various shades of pink to brilliant...

Jan 1, 1943

The extra information brought by further drilling may seem necessary to achieve control over block grades if elementary estimation techniques are used. However a geostatistical study of an Australian deposit shows that better estimation techniques at the end of the first drilling campaign are sufficient to achieve required control.Subsequent drilling would be essentially wasteful.

Jan 1, 1975

By Greaves M. C

X-ray fluorescence spectroscopy used for the analysis of mill samples results in improved control of flotation concentrators.Techniques and equipment for sampling pulp streams, filtration and drying, grinding, briquetting and X-ray fluorescence analysis of samples have been developed.The current methods in use permit the analysis for lead and zinc in six pulp samples within 30 min total elapsed from the start of sampling. The X-ray method gives a precision at least equal to the former routine wet-way assay methods.The equipment is used also for pilot plant control, as a means of solving complicated analytical problems and in the rapid qualitative analysis of exploration samples.INTRODUCTIONIn milling and concentrating operations, classical methods for the assay of lead and zinc have been mainly of use for accounting purposes and for the post-mortem examination of plant operations, but have been of little value for rapid mill control. Where attempts have been made to apply these methods to control assaying, it has been necessary to modify the procedures and introduce short cuts which have tended to reduce their reliability.Even with these shortened procedures, the time taken to obtain a limited amount of information rendered them of little value for the control of milling operations where sudden, large fluctuations can occur. In recent years, a number of new and rapid analytical techniques, based on physical rather than chemical principles, have been introduced.These include direct reading emission spectroscopy, x-ray fluorescence spectroscopy and atomic absorptionspectroscopy.

Jan 1, 1964

The projection of operating costs for mining, processing, and other site operating costs is an exercise which can be fraught with considerable peril. Not only are the physical characteristics of each mineral property unique, but a range of other factors will influence the consultant's approach to compiling cash flow estimates. This paper details some of the techniques used in estimating operating costs for use in order-of-magnitude cost studies and feasibility studies, and describes how to avoid common areas of difficulty. A series of examples relating to open pit gold mining and processing cost estimates illustrate these problems, and various corrective methods are described. The mining and treatment processes, and their associated cost elements, are followed in sequence of operation from on-going ore delineation through to disposal of the product. In addition the problem of assigning management, administration and overhead costs along with taxation allowances is addressed. Of critical importance is the application or possible misapplication of accrual procedures to the cost elements. In many cases such misapplication can introduce more pronounced errors with projects of short duration, such as the typical open pit/C.I.P. gold operation commenced in the last decade. The importance of providing verification of estimates depending upon the standard of the cost study is also investigated, and opinion is provided upon the minimum levels of verification necessary at various stages. Finally, the amalgamation of the various individual cost elements into a coherent whole is reviewed.

Jan 1, 1990

Every automatic citizen is an automatic recipient of a miner's right under the present Mining Act (Chapter 195), but this alone does not entitle any automatic citizen to mine for minerals on any land, even his customary group's land. Without complying with requirements of the Mining Act, any automatic citizen who engages in mining solely on the basis of a miner's right would be mining illegally. He would also be engaged in illegal mining if he mines on customary or other non-government land. Even if mining is legally pursued by an automatic citizen, he does not acquire ownership of minerals without first making the required royalty payments to the State.

Jan 1, 1991