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For decades strip mining with discon tinuously operating 'draglines and shovels has been the most economical operation method in the shallow hard coal opencast mines of Aust- ralia, North-America and some other countries. Continuously operating equipment such as bucket chain excavators and bucket wheel excavators in combination with conveyor belt systems, conveyor bridges and stackers had been deve- loped in Germany; during the last 25 years this type of equipment has been further developed in order to allow a high degree of rationaliza= tion as to opencast mines in unconsolidated overburden in Germany, in many European couh- tries, in India and in Victoria. The differing compactness of the layers to be mined, the increasing mining depth, the adverse over- burden to coal ratio and geotechnical con- ditions account for the combined use of con- tinuously and discontinuously operating equip- ment and systems. This paper is to demonstrate some projects showing the combination of continuously and discontinuously operating equipment which aims at optimizing opencast mine operations. It will be reported on the following combinations: - combined use of bucket wheel excavator/

Jan 1, 1981

ALTHOUGH the mineral Stannite (Cu2S, FeS, SnS2 , also known as "bell 'metal" ore, tin pyrites, etc.) is found in various parts of the world, in only three iocalities has development proved it to exist in sufficient quantity to warrant the erection of treatment plants. Two of those mines are in New South Wales and one is an Tasmania. The writer will deal with the latter-the Conah mine, Zeehan, Tasmania, it being the most important and extensive occurrence so far worked. The Conah mine was first worked by a Tasmanian company for silver-Iead, and was fairly remunerative until the zone of secondary enrichment was passed through, when the lodes became too poor for further exploitation. During the time that the line was thus operated the stannite lode was discovered. It occurs in a graphitic slate, which, in common with the slates and spilites of the Zeehan field, is probably underlain by the stanniferous granite which outcrops two miles to the west. The Conah stannite lode is older than the galena lodes of the district, being faulted by one of the latter. Near the surface the lode was very rich.Shipments were sent out assaying 150 oz. of silver per ton, 20% copper, and 18% tin. An .apparently homogeneous sample of stannite, analyzed by the writer for the Tasmanian Geological survey, gave the following results:

Jan 1, 1915

Zinc produced by pyrometallurgical processing techniques suffers the disadvantage of restricted market potential because of its impurity contents, typically lead and cadmium. Market zinc to the Special High Grade (SHG) standard can only be produced by reflux distillation refining, which is costly in terms of energy and equipment, and potentially capacity limiting. Recent published laboratory work suggested that molten salt electrorefining of zinc metal is a potentially much cheaper alternative to the reflux distillation refining. The extrapolation of the laboratory results to an industrial configuration, however, resulted in an estimated power consumption for electrorefining and associated costs offering no advantage over current reflux distillation practice. A review of this estimate now shows that a serious error in calculation was made, and that the energy consumption for the electrorefining of molten zinc would be an order of magnitude lower than that for reflux distillation refining. While this is a promising indication, further research is required before development towards an industrial scale operation is warranted. This would particularly relate to the extent to which adverse electrolyte deterioration may take place and its potential effect on the anode and cathode efficiencies of the process. This paper considers the laboratory investigations required to explore the industrial potential of the molten salt electrorefining of zinc and foreshadows some of the practical problems to be solved in further development.

Jan 1, 2000

While there is reasonable agreement on the basic chemistry of the slag fuming process, there has been an on-going debate for nearly 50 years as to the nature of the rate controlling factors in its industrial application. There have been advocates in the technical literature for thermodynamic limitations on the one hand or kinetic limitations on the other. The different viewpoints result in very different predictions as to the technical and commercial potential of the process. A resolution of the debate becomes of importance as pyrometallurgical processes are advocated as a means of extracting environmentally deleterious elements from metallurgical wastes. The present paper reviews the arguments in favour of both equilibrium and kinetic control and puts forward the view that much of the evidence for limitation of the process by kinetic factors under all conditions is unconvincing. It is maintained that the process can approach thermodynamic equilibrium under industrial conditions and that this determines the ultimate limitation on its technical performance. It is acknowledged, however, that kinetic considerations may cause the batch process to fall well short of performance predicted on thermodynamic grounds. The strong process limitation arising from the influence of chemical thermodynamics on the likely outcome of a hypothetical continuous fuming process is contrasted with optimistic forecasts resulting from the extrapolation of process models based only on kinetic considerations.

Jan 1, 2000

As part of a prefeasibility study being undertaken by Newcrest Mining Limited, the Cadia East Implementation Team has developed an access decline to the proposed underground operation. This paper describes new technologies that have been employed in this development, which include: high frequency drifters that have penetration rates one and a half times that of competitors, ensuring minimal increase in drill time, despite rounds greater than 5.5 m;automated drilling used in conjunction with laser navigation and face pattern design software, which facilitates exact positioning of hole collars, lengths and lookouts for accuracy and repeatability; andemulsion charging that reduces manual handling; has variable string loading capabilities, via its hose retraction system, for perimeter control and reduced fume characteristics. A Six Sigma improvement process was used to support the system change undertaken and demonstrated that development rates improved 60 per cent above the comparable single heading benchmark.

Jan 1, 2008

By Bulters J, Sheppard I

Two blasthole density logging programmes have been conducted on the Mt Whaleback iron ore mine to evaluate the use of this type of logging as an aid to blast pattern design. The first programme also involved the setting up of a Density Test facility with which to calibrate the density probe. The programmes indicated that about 22-23 blastholes can be consistently logged per day at a cost of $1.30 per metre. Even though this is only half the rate required to log the average number of blastholes drilled daily on Mt Whaleback, testwork indicated that no significant loss of accuracy results if only half the holes in a pattern are logged. The major results of the programmes were: 1. The density range for black pyritic Shale is 2.2-2,9 g/cc. 2. The density range for soft to medium hard BIF is 2.1-3.0 g/cc. 3. The density range for hard BIF is 3.0-3.6 g/cc. 4. The front row blastholes show consistently lower densities than the main body holes due to blast damage. 5. A low density zone extending to a maximum depth of 6 m occurs at the top of most blastholes and results from blast damage from the bench above. These density results have been used to implement savings in drilling and blasting via pattern expansion and charge optimisation of blastholes. Eight ore

Jan 1, 1986

By R M. Tosdal

Intrusion related ore deposits are widespread in the Central Peruvian Cordillera Occidental and adjacent high-plains to the east and include porphyry Cu (-Au, Mo; eg Morococha), Cu-Zn (Pb-) skarn (eg Antamina), Pb-Zn-Ag carbonate hosted vein deposits (eg Uchucchacua), cordilleran base metal (eg Cerro de Pasco) and epithermal deposits (eg Quicay). Geochronology and petrochemistry of intrusive rocks associated with mineralisation reveals that: most ore deposits were emplaced in the late middle to early late Miocene; and are related to calc-alkaline granodioritic igneous rocks with Sm/Yb >3, Sr/Y >40 and Y/Th <1.5. The largest deposits, including Antamina, Colquijirca and Cerro de Pasco are associated with intrusions with Sm/Yb >4 and which, as indicated by Pb and Sr isotopic data, have undergone relatively moderate middle and upper crustal assimilation. The chemical signature of igneous rocks related to mineralisation likely reflects melt equilibration in the lower crust at a crustal thickness of more than 45 km. Mineralisation was favoured by a change from normal to flat subduction, resulting in increased compression, crustal thickening and subsequent cessation of the magmatic arc. Premiocene ore deposits do occur, but are restricted to a broad E-W corridor between Uchucchacua and Milpo and probably were controlled by a crustal-scale structural discontinuity across the strike of theAndes. Not all igneous rocks with high Sm/Yb and Sr/Y ratios did acquire their trace element signature in the lower crust. Petrographic and Pb isotopic evidence indicates shallow crustal hornblende fractionation or assimilation of pelitic material as possible causes for high trace element ratios in some rocks. These are apparently unrelated to polymetallic mineralisation. Thus, critical evaluation of petrographic and geochemical data in metallogenetic studies, especially in areas with complex basement architecture such as Central Peru is critical and should not be reduced to simple trace element ratios. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

The first geological maps of parts of Australia were produced in the 1830s and 1840s, many being for purely practical purposes, such as indicating the occurrence of coal, iron and other essential materials. Mineral location maps were also first made about the same time.More systematic geological mapping commenced in the 1850s when large parts of New South Wales and Victoria were studied in government-sponsored surveys by geologists such as Samuel Stutchbury, Alfred Selwyn and Reverend William B. Clarke. Their work coincided with the opening up of most of the major goldfields of eastern Australia, which led to the establishment of Departments of Mines in the separate Colonies (later States within the Commonwealth of Australia).A few companies employed consultant geologists at this time, and the mapping by Frederick Odernheimer is particularly notable. Geological study of Australian ore-deposits and mineralisedareas was influenced by the continental European geological ideas of men such as Odernheimer as well as by those from England. Both geological and mineral maps were a feature of Colonialdisplays presented at major international exhibitions during the second half of the nineteenth century. The maps accompanied rock and mineral collections which showed the known and potential mineral wealth of the Colonies. Such displays raised interest in the potential for development amongst government officials, entrepreneurs and investors in Australia and abroad.By the 1880s most of the Colonies had produced basic geological maps, and several maps of the whole continent had been published. Although systematic mapping of the continent become a reality only in the 1950s, the nineteenth century geological and mineral mapping formed the basis for the development of the major coal, artesian water, and metalliferous mining regions of Australia.

Jan 1, 1990

By R J. Everett

The mining industry is beginning to adopt quality systems based on the requirements of International Standards for quality assurance, such as the ISO 9000 series. Indications from similar industries are that considerable benefits are to be had from their adoption. This paper describes the use of the International Standard ISO 9001 for quality assurance within BUKA Minerals Limited. This provided guidance for the development of a clear statement providing agreement on the processes to be followed and the outputs required when dealing with outside service providers. Discussion focuses on the interaction with BUKAÆs consultants and contractors during the specification stage, resulting from the application of quality assurance techniques. Risk analysis was used to identify and manage the risks associated with the companyÆs contract for geotechnical and mine design services and the tender for a mine development program of work during the feasibility stage of the project. Setting acceptance controls for the deliverables from such contracts is traditionally fraught with difficulty. BUKA used Failure Mode and Effect Analysis for exposing underlying risks that were not effectively being countered. The briefs were reviewed and additional controls were developed to manage the risk. These controls have provided clearer instructions to the consultants and contractors, indicated audit points for the company and defined the deliverables. There exists within the company, and among its outside service providers, a clearer understanding of what is to be achieved and how it will be measured. The process has imparted considerable confidence to both parties on how the work will proceed and what outputs are to be provided. Some discussion is provided on how quality principles are being applied throughout industry and commerce, generally, and how they may apply to the mining industry. The paper argues that, far from being an appendix to the tendering process, Risk Management should be a mandatory step integrated into the definitions of the work.

Jan 1, 1998

By E Widzyk-Capehart

The conventional ammonium nitrate fuel oil (ANFO) loader utilises a pneumatic system to control the flow of ANFO (via rotary actuator/ball valve) and air (via an auxiliary air valve). This system, though relatively simple and reliable, has several drawbacks with respect to ease of control and level of automation. In this paper, a radio frequency (RF) remote control for explosives charging is discussed. The system design incorporates electric solenoid valves to control the rotary actuator and the auxiliary air valve. All operations associated with explosives charging are selectable at the remote and are completed according to a modifiable time sequence. This allows the following charging sequence to be reduced to a single momentary application of the remote:removal of water from the hole prior to charging with ANFO; charging of the hole for a preset but adjustable period of time; and removal of the remaining ANFO from the ANFO hose. A specially developed remote switch allows the operator to maintain two-handed control of the ANFO hose whilst achieving full control of the charge-up process. Failsafe electronic architecture is incorporated into the systemÆs design to increase safety to the highest level. Should the RF remote control fail, a wired remote is included in the system to allow for the charging process to continue, albeit at a reduced level of control. The application of the RF remote control system in an underground explosives charging operation minimises and/or eliminates many problems associated with the use of the conventional charging system. These include: the wet-hole problem, trip and entanglement hazards, air embolism and the two-man loader control requirement. The developed remote control unit proved to be effective at removing water from wet holes leading to increased face advance per drilling operation. It proved to be economically feasible, allowed for an increase in systemÆs dependability and safety factor and for a truly one-man operation which resulted in reduced manpower.

Jan 1, 1999

By J Vann, S Jackson, O Bertoli

Ordinary kriging and non-linear geostatistical estimators are now well accepted methods in mining grade control and mine resource estimation. Kriging is also a necessary step in the most commonly used methods of conditional simulation used in the mining industry. In both kriging and conditional simulation, the search volume or ækriging neighbourhoodÆ is defined by the user. The definition of this search can have a very significant impact on the outcome of the kriging estimate or the quality of the conditioning of a simulation. In particular, a neighbourhood that is too restrictive can result in serious conditional biases. The methodology for quantitatively assessing the suitability of a kriging neighbourhood involves some simple tests (which we call æQuantified Kriging Neighbourhood AnalysisÆ or QKNA) that are well established in the geostatistical literature. The authors argue that QKNA is a mandatory step in setting up any kriging estimate, including one used for conditioning a simulation. Kriging is commonly described as a æminimum variance estimatorÆ but this is only true when the neighbourhood is properly defined. Arbitrary decisions about searches are highly risky, because the kriging weights are directly related to the variogram model, data geometry and block/sample support involved in the kriging. The criteria to look at when evaluating a particular kriging neighbourhood are the following: the slope of the regression of the ætrueÆ block grade on the æestimatedÆ block grade; the weight of the mean for a simple kriging; the distribution of kriging weights themselves (including the proportion of negative weights); and the kriging variance. Outside of the technical geostatistical literature, there is little in the published domain to describe the nature of QKNA and no practical presentation of case examples. In this paper we attempt to redress this by setting out the calculations required for QKNA and defining some approaches to interpreting the results. Several practical worked mining case examples are also given. Finally some comments are made on using the results of QKNA to assist with block size selection, choice of discretisation and mineral resource classification decisions.

Jan 1, 2003

The design of the grinding section is discussed and details are given of the equipment installed for the autogenous grinding of ores from the C.S.A. mine at Cobar.The first section of the concentrator commenced treating ore in June, 1965 and operating experience and maintenance requirements since that time are outlined.

Jan 1, 1969

Throughout the industrial world, Ilmenite, Rutile, Monazite and Zircon mineral sands play a KEY role in numerous industrial processes. Australia's ilmenites, rutiles, and synthetic rutiles are of vast importance in the world of titaniferous ores, and Australia has been the world leader in the field, and continues to adapt to new demands with alacrity. These materials enter a world titanium dioxide market that will exceed three million tonnes in 1990 at an expected growth rate of 2.3%. Many experts place current use in excess of 2.5 million tonnes of contained Ti02. Here we have a slide that illustrates projected growth rates in consumption, in SCM's view.

Jan 1, 1986

By Johnson M, Gaudin A

With the advent of Computer aided mapping and surface modelling techniques Geologists and Engineers have had to become familiar with the capabilities and limitations of these systems to effectively use them. In this paper we will trace a short history of the rather rapid progress in this area. From this historical perspective we will make some observations and use these to guess at what the future holds. We hope that this paper will assist in clarifying the develop- ments in computer assisted mapping and modelling and promote thought on how these techniques may be best applied to the problems of the Mineral Industry.

Jan 1, 1983

By Marsham B, Baker D. C

The expansion of New Broken Hill Consolidated Limited (NBHC) concentrator necessitated the installation of hydrocyclone classifiers where rake classifiers had previously been used. Commissioning of the circuit and optimisation of circuit performance has highlighted problems related to classification of sulphide minerals. Testwork initiated to solve these problems has been used to develop cyclone models which have been incorporated in a ccnputer control strategy for the grinding circuit as a whole. The modifications to the circuit during the commissioning phase and the control philosophy are outlined.

Jan 1, 1983

By Adamiak Z. P

A study has been made of the influence of bentonite type on the wet strengths, dry strengths and drying rates of pressed iron ore pellets. Measurements of the influence of bentonite on the kinetics of growth of pellets are also reported. The results show that bentonite decreases the rate of growth of pellets and the drying rates of pellets while increases are observed in both wet and dry strengths. The results have been interpreted in terms of the physical and chemical charact- istics of the bentonite and the suitability of a given bentonite for particular pelletising operations has been discussed.

Jan 1, 1973

By R M. Papini, A C. Araujo, A E. C Per

Flotation is an important process used in the concentration of iron ores. One of the challenges for process engineers is the low metallurgical recovery associated mainly with the fines fraction. In this work, the use of synthetic flocculants in iron ore reverse cationic flotation was investigated. The flocculants utilised were polyacrylamides of high molecular weight and different ionic degrees. Bench scale flotation tests were performed to compare the flotation performance with and without addition of polyacrylamides. It was observed that cationic and non-ionic polyacrylamides cause a significant increase in the metallurgical recovery. The anionic flocculant did not improve the flotation performance. An adverse effect was a slight increase in the silica content of the concentrate. Flotation with polyacrylamides was influenced by the hydrodynamic conditions of the pulp, such as agitation and the weight percentage of solids in the flocculant conditioning and flotation stages.

Jan 1, 2005

The number of employees required to operate a continuous operation was determined. The fixed and variable costs of the operation were separated, generally along the lines of labour and stores components. Proprietary `MicroPlanner' scheduling software was used to assess resource utilisation under the constraints generated by seven-day operation to determine the level of resources required and ensure that the maximum use was being made of all resources. The mine economic model was used to account for both the fixed and variable costs of the various task to determine the cost and net revenue of the various scenarios. The analysis indicated that mine output could be increased while reducing the unit production cost. Several eight- and 12-hour, seven-day rosters were sourced and ranked for their potential to improve production and communication, and for their effect on employee health and lifestyle.

Jan 1, 1995

It has long been recognised that applications of the Net Present Value (NPV) investment decision making methodology can have serious deficiencies in situations where investment can be delayed and, once made, various options allow increases or decreases in the level of output. NPV valuation can undervalue the project if it does not incorporate future flexibilities or ""options"". It is important to realise that a proper valuation of a project (ie, valuation of its future cash flows) must incorporate an analysis of optimal future decisions involved in managing the project. Current valuation cannot be divorced from a consideration of future decision making. There is now a considerable amount of literature, mainly academic, identifying and exploring ways of remedying these deficiencies in the application of NPV. While the necessity of period by period analysis is sometimes acknowledged, little if any practical illustrative model building has been published to date, aside from algorithms using continuous time stochastic processes which deny access to the uninitiated.

Jan 1, 1994

By W Lu, D Wang

Study of coal oxidation at low temperatures forms the basis of investigating the inherent properties of spontaneous combustion of coal. In general, the process of coal oxidation at low temperatures is very complex, involving many factors. Experiments examining the properties of oxidation and ignition of coal have been carried out. Based upon the results of these experiments, the catastrophe properties in the process of coal oxidation are analysed and the mechanism of catastrophe is proved for the ignition of coal. A folding catastrophe model is also established for the process of coal oxidation. Results obtained show that the process of coal oxidation to ignition is discontinuous, where the coal-environment system yields structure destabilisation. The system can jump from one stable attractor to another. The research results presented in this paper help to show the irregularities of coal oxidation at low temperatures and how to pursue effective control measures.

Jan 1, 2005