Search Documents

By P G. Fuller

The Woodlawn Mine near Canberra faced the challenge of poor ground conditions from the commencement of underground operations 1987. Talcose shears bounded the dense massive sulphides on both the hangingwall and footwall side of the orebody. In another area the talc existed not only on the edges of the orebody but through out it as well. The country rock was relatively weak shales compounded by a low stress environment that allowed the wall rocks to fall apart quite easily. The challenge for the operators was to overcome the poor ground conditions. This was done by attacking the problem from three directions:technology, how technology is applied, human relations and leadership by all levels of the Management team, and by ensuring that these processes meshed together well.Woodlawn in it early days as an underground mine enlisted the assistance of BFP (Formerly Barrett Fuller and Partners) as a second set of eyes to assist with the assessment of the ground control procedures. The results are discussed in this paper. The progression to this end result included:non-contract payment systems; ground control training for the full range of mining personnel; the development and enhancement of cable bolting and shotcreting equipment; the development of Practical Standard Work Procedures by mine operators; and innovative use of shotcrete and cables bolts to control extremely poor ground conditions.

Jan 1, 1998

By R Balusu

This paper provides an overview of computational fluid dynamics (CFD) modelling capability developed by CSIRO with the aim of improving the knowledge of flow migration dynamics within longwall goaf areas. The CFD models can be used to study the ingress of oxygen into the goaf in different ventilation scenarios and goaf drainage arrangements. This approach not only helps the design of effective gas control strategies but also the management of spontaneous combustion risk in the goaf. Innovative goaf inertisation strategies have been developed and implemented during longwall sealing operations. Work is continuing to develop general guidelines of proactive goaf inertisation strategies to suppress the development of spontaneous heating behind active longwall faces.

Jan 1, 2005

By B Hall

The authors have undertaken many independent mine optimisation and operational improvement projects at Australian and international mining operations over the past decade. This work has provided an understanding of the underlying practices responsible for the good long-term performance of some operations, and the failure of others to achieve their objectives. Good long-term performance, and value creation can be achieved through a logical and rigorous process of identifying the optimal mine plan (æThe PlanÆ) that delivers the corporate goals, establishing appropriate performance measures that are aligned with these goals, and ongoing monitoring of compliance with the established targets to ensure the operation reliably achieves The Plan. A number of practical methods have been developed and implemented to assist mining operations deliver their corporate goals. This paper outlines some of these methods, providing some fundamental guidelines that will assist in the establishment, and reliable achievement of The Plan that delivers the corporate goals.

Jan 1, 2006

By P Lilly

Blasting is the primary comminution process in most mining operations. This process involves the highly complex and dynamic interaction between two main components. The first is the detonating explosive and the second is the rock mass into which the explosive is loaded. The mechanical properties of the rock material (such as dynamic strength, tensile strength, dynamic modulus and fracture toughness) are important considerations in understanding the blasting process. However, it is the characteristics of the geological defects (joints, foliation planes, bedding planes) within the rock mass that ultimately determine how effectively a blast performs in terms of fragmentation, all else being equal. The defect characteristics include, but are not limited to, their orientation, spacing, and mechanical properties. During the blasting process, some of the geotechnical characteristics of the rock mass are substantially changed. From the blasting outcome point of view, the most notable and important is the change in fragment size distribution that the rock mass undergoes. The pre-blast in situ defect-bounded block size distribution is transformed into the post-blast muckpile fragment size distribution. Consequently, it is fundamental to our understanding of and ability to predict the blasting process that both the blastability of a rock mass and its transformation into the fragment size distribution can be appropriately quantified.

Jan 1, 2001

This paper critically reviews the role of institutional research contractors (eg universities and the CSIRO) in the delivery of effective research, development and demonstration outcomes in mineral and coal processing to the Australian mineral industry. The criteria by which such R&D is justified, and the problems of quantifying the benefits of such research, are considered. Third-party funding mechanisms such as NERDDP and AMIRA are reviewed in the context of the difficulty of setting national research priorities. Some case studies are presented which illustrate both the problems and the advantages of institutional research for industry. The transfer of research outcomes to industry is identified as a significant problem which limits the effectiveness of all institutional research. Other topics reviewed include research management, the relationship between industrial companies and their research contractors, and the real costs of research. The paper offers suggestions for the ingredients needed for a successful industry-institution relationship, based on the Australian experience. It is concluded that the Australian model for this relationship is a very effective one, although there is still room for improvement.

Jan 1, 1992

By W Uhlmann, U Grnnewald, B Nixdorf

Flooding with surface water is the preferred technique for the abatement of acidification from pyrite oxidation in the lakes of abandoned Lusatian lignite mines. However, water resources of the region are limited and in addition, interruption of water inflow during the summer and the termination of the flooding process after reaching the final water level can lead to a re-acidification of the lakes. The development of three mining lakes with a surface-water flooding history of six to 28 years was analysed û in two lakes on the basis of fortnightly to monthly hydrochemical monitoring data. During summer flooding interruption, the younger lakes showed a decrease in pH from neutral down to pH 4. The degree of the pH decrease depended on the intensity of the groundwater inflow from the overburden dumps and this affected the hypolimnion more than the epilimnion. The third lake was flooded 28 years ago and up to now, interruption of the surface water inflow resulted in re-acidification. These three examples were able to show the benefits and limits of the surface water flooding technique for the abatement of Lusatian mining lake acidification.

Jan 1, 2003

By Whiten W. J

Data from ball mills of a wide range of sizes are analysed using detailed mathematical models and non-linear least squares fitting techniques. In this way model parameters are obtained describing the behaviour of ball mills over a wide range of mill sizes and operating conditions. These parameters define the flow and breakage of each size fraction of ore in the mill. Flow of coarse particles through the mill is found to depend on the proportion of coarse particles present. The breakage rates of coarse particles are found to decrease markedly with mill diameter for mills over 3 m in diameter.Simulation of grinding circuit throughput at constant productsizing for different mill diameters shows that throughput is proportional to theoretical mill power consumption for mills up to about 3 m in diameter. Thereafter the throughput gradually falls below that indicated by power consumption, the decrease becoming quite significant for large diameter mills. Simple qualitative physical arguments are presented to explain this behaviour. The models developed have applications to ball mill scale up. Work on their further development is continuing.

Jan 1, 1982

The Australian mining industry is at an interesting stage in its development. Of the large number of mining companies in Australia, some are still solely domestic in their focus. others have made their first tentative forays offshore, and others are global players of significance in the world industry. It is not long ago that the entire industry was almost exclusively domestic in its focus. Very few companies before the early 1980s had ventured offshore, and those that did so were considered quite risque. The initial moves were made mainly by large companies who could afford to lose the funds expended in getting started in a range of offshore locations.

Jan 1, 1995

By A A. Struthers, A D. Farmer

Power ultrasound may be applied to enhancing the processing of minerals. The enhanced performance is achieved through the very localised high-energy release at the mineral surface from the collapse of cavitation bubbles produced by power ultrasound. This gives rise to two effects: initially, the rapid cleaning of mineral surfaces û of oxidation products and coatings of fine adhering gangue minerals û and the attenuation of the boundary layer at the mineral surface during leaching, which allows fresh leachant to contact the surface more readily. Work carried out at CSIRO in conjunction with Tiwest Joint Venture has demonstrated that it is feasible to apply ultrasound to the leaching process in order to enhance the removal of contaminating minerals. When applied to the production of synthetic rutile from reduced ilmenite produced by the Becher process, the use of ultrasound proved beneficial to both the aeration and the final acid leach process. The effect of ultrasound was less marked in the case of the aeration process, once the method of introducing and dispersing the air was optimised. In the subsequent acid leaching step of the Becher process it was found that the application of power ultrasound could reduce leaching time to about one quarter of the time required when only agitation was employed. Projected capital and operating costs, based on currently available commercial equipment, are also presented, and indicate that the use of ultrasound is commercially as well as technically feasible.

Jan 1, 2001

When Australian voters elected a Labor Government in March 1983 the value of the Jabiluka uranium deposit as an asset of Pancontinental Mining Limited effectively evaporated overnight. The day before the election, Jabiluka was Pancon's principal asset, with the Company's 65% stake in the deposit having a market value of the order of $US1 billion. This value had been set by an agreement reached with a potential customer, who was prepared to pay $US150 million for 10% of Jabiluka. The months before the election had been the culmination of ten years of unremitting effort to bring what was then the world's largest reserve of high'grade uranium ore into production. These efforts had included two and a half years of negotiations with the local aborigines, as well as exhaustive environmental studies and conceptual mine planning. All domestic approvals required to develop the Jabiluka deposit had been given to Pancontinental and marketing efforts had successfully placed about 50% of the expected uranium production with overseas utilities. It appeared that Jabiluka was about to emerge as one of the world's great mining enterprises. The election of a government with an anti-uranium policy stopped Jabiluka dead in its tracks. Pancontinental's largest asset had effectively become worthless and the Company appeared to be facing a bleak future.

Jan 1, 1987

It is a very great pleasure indeed to participate in this interesting and important seminar. My two visits to Australia in the past have been extremely pleasant and this one is equally so. My task is to tell you what has been happening in the United States, in these past few years especially, in regard to the management of our air resources and to present in some detail the difficulties we in the copper, lead and zinc smelting industries have been experiencing. The sudden upsurge in interest in air pollution in the United States is a strange phenomenon indeed - strange because we've had air pollution a long time, just as long as there have been large cities using fossil fuels for heating purposes. And the problem has been studied for quite a long time. As early as 1919 studies by the U. S. Bureau of Mines were done in Salt Lake City, where I .live. In the winter of that year extensive measurements were made of airborne particles - dust and smoke. The average concentration of particles found was 870 micrograms per cubic meter of air. A very large number compared to levels we find today. A microgram of course is a very small unit, one twenty-eight millionth of an ounce. A fine human hair two inches long weighs about 100 Micrograms.

Jan 1, 1971

By Nettle W. H V

THE past few years have seen a considerable expansion of the roasting of blende in Australia. The bulk of this blende is Zinciferous concentrate from Broken Hill and now forms a very considerable source of sulphur for the acid manufacture. It will bereadily conceded that Australian sentiment is in favour of utilising all known potential wealth, especially that won from below ground, as this once disposed of is gone forever. If Australia does not make sulphuric acid from her sulphide ores we may be sure that the purchaser of these ores will do so if in any way possible. It must not be assumed, then, that the difficulties met are mentioned with the idea of undue criticism, but rather to show that, although most of the intial troubles have been overcome, there are still a few to be encountered; and with the hope that comment brought forth will aid in the solution of the problems facing an industry at present little more than in its childhood as far as Australia is concerned.Blende roasting is done in mechanical furnaces of various makes, and mostly without the aid of other fuel than the sulphur in the ore. It will be our aim to touch on the various difficulties in the order in which they occur in the train from furnace to acid plant.

Jan 1, 1926

By J Koppe, J F. Costa

A fundamental error of sampling occurs when a sample is extracted from a larger mass of ore or lot. The act of sampling requires that all particles belonging to the lot have an equal chance of being extracted. This type of sampling is called unbiased sampling. The sampling equipment (herein referred to as the sampler) should be constructed with some additional mechanical characteristics to guarantee that the samples will be unbiased. Samplers, extracting increments from a continuous flow, such as a conveyor belt, collect aliquots at regular time intervals. These time intervals relate to the number of aliquots extracted from a given mass of lot, whilst passing through the continuous flow. The frequency of extractions will influence the precision or the error of the sample (integration error). Further, the ore variability influences the amount collected from the continuous flow. Normally, the sampling protocol utilised is designed for the extractions obtained from the conveyor belt, omitting any error committed during this operation, ie the error of extracting from the continuous flow. This study aims to analyse the error of sampling a continuous flow by using a variogram with added on auxiliary functions. Each different piece of material passing through the flow will exhibit a distinct temporal variogram, which should influence the frequency of the samples being extracted for each chosen sampling error. The methodology used is presented in the form of a case study from a coal processing plant.

Jan 1, 2005

By R Hall

The magmatic arcs of SE Asia and SW Pacific contain some of the worldÆs major magmatic-hydrothermal gold deposits. Most gold deposits in SE Asian and SW Pacific arcs formed during periods of plate reorganisation rather than during periods of normal or steady state subduction. These plate reorganisations were caused initially by the collisions of the Australian Craton with the Philippines-Halmahera Arc and the Ontong Java Plateau with the Melanesian Arc at ~25 Ma. A second Mid-Miocene period of mineralisation accompanied plate reorganisation following maximum rotation or extrusion of Indochina and cessation of spreading in the South China Sea at ~17 Ma. However, the vast majority of deposits from New Zealand to Taiwan formed since 7 Ma during an important period of tectonic reorganisation that accompanied and followed changes in the relative motion between the Indian-Australian and Pacific plates between ~8 and 3.5 Ma. Magmatism in unusual tectonic settings produced the most abundant and largest deposits with many deposits associated with high-K calc-alkaline, shoshonite, adakite and alkaline magmatism. In particular peak mineralisation appears related to melting of sub-arc lithosphere that has been previously modified by subduction. During large-scale plate reorganisation this can occur towards or at the end of a period of normal subduction, following arc collision or accompanying subduction reversal at approximately the same time in different parts of a complex system of arcs such as in SE Asia and the SW Pacific.

Jan 1, 2005

THIS SYMPOSIUM ON AUSTRALIAN BEACH SANDS IS MOST TIMELY; WHEN WE ARE APPROACHING PEAK PRODUCTION FROM THESE RESOURCES AND WHEN PRICES ARE GOOD, BUT THE RESOURCES CAN BE SEEN TO BE COMING TO AN END IN THE LIFETIME OF OUR YOUNGER COLLEAGUES - 20 TO 25 YEARS AS WE HEARD FROM ROY TOWNER TODAY. THE SPREAD OF PAPERS HAS BEEN 15 PERCENT EACH ON GEOLOGY AND THE MINERAL RESOURCES, WITH 25 PERCENT ON LAND USE AND ENVIRONMENTAL PROBLEMS. I AM PLEASED TO SEE 20 PERCENT HAS BEEN ON TREATMENT PROCESSES AND 25 PERCENT HAS BEEN CONCERNED WITH DOWNSTREAM USES. I SUSPECT THESE RATIOS ARE DUE IN PART TO THE WAY PAPERS WERE CALLED FOR, BUT THEY ALSO SUMMARISE CLOSELY THE BALANCE OF INTERESTS IN THE INDUSTRY. NOTE AGAIN; 30% CONCERNED WITH SUSTAIN -ING RESOURCES, BUT 25% WATCHING LAND USE AND IMPOSING CONTROLS; 20 % IMPROVING THE PRESENT PROCESSING, AND A HEALTHY 25% WITH AN INTEREST" IN WHAT HAPPENS TO THE MINERAL CONCENTRATES. I SHALL RETURN TO THIS FOURTH POINT AT THE END OF MY REMARKS. THE POSSIBILITY OF ADDITIONAL HEAVY MINERAL SANDS IN NEW AREAS WAS HINTED AT BY M.S. SHEPHERD (EG TERTIARY SHORELINES OF THE MURRAY BASIN). OLD FOSSIL SHORELINES, WELL REMOVED FROM PRESENT SHORES ARE AN IMPORTANT MINERAL SOURCE IN CHINA AND IT WOULD HAVE BEEN INTERESTING TO HEAR FROM THE SEVERAL COMPANIES EXPLORING IN THE MURRAY BASIN. I ALSO NOTICED THAT WHILST OUR MONAZITE

Jan 1, 1986

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

WITH the exception of the deposits of the Milburn Cement Co near Dunedin, Wilson's Portland Cement Co., on the Mahurangi River (a short distance north of Auckland), and those of the New Zealand Portland Cement Co., at Limestone Island, the cement. Tesources of New Zealand remain practically undeveloped. The Milburn Company utilizes a mixture of limestone and mud for the manufacture of cement, while Wilson's and the New Zealand Portland Cement companies both have the advantage of a natural cement stock which requires but small additions of highgrade limestone to give the mixture required. The plant and deposits of the New Zealand Portland Cement Co are located in Whangarei Harbour, some six miles from thetownship of Whangarei. The works and dwelling-houses are situated on Limestone Island, which, with an area of 92 acres, and rising to a height of 212 ft., supplies the bulk of the raw material required. In addition to the island, the company possesses a high-grade limestone area of, roughly, four acres, situated on the mainland, 11 miles to the south. A better location for a cement works could not well have been chosen. On the east side of the island there is a deep channel, which never shows less than 18 ft. of water alongside the company's...

Jan 1, 1911

CABS - Costs and Budget System - is being developed to provide more appropriate tools to assist cost control. The most important of these tools is responsibility accounting, that is to ensure the respons- ibility for costs and budgets is placed at the lowest possible managerial level in the Company. The system design and computer techniques utilized include the use of on-line facilities for enquiry purposes plus entry and validation of data. Data base management is used to permit the complex relationships that exist between data in CABS to be defined and maintained. The system must be flexible in order to cater for organisational and other maintenance changes with minimum time delays. The major outputs of the system are reports produced in several cost dissections, by responsibility, by products by cost collection group and type of expense. A significant role in CABS has been played by users. This includes development, control and review of the system proposals in order to ensure that the objectives and requirements from all sections in the Company are met. This role has included Project Leader for the system plus a committee formed to provide formal acceptance of the system Design.

Jan 1, 1977

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

The efficient development and exploitation of an orebody relies on an understanding of the mineral characteristics of the deposit. This information is valuable throughout the mining cycle - during exploration, assessment, testing, design, operation and rehabilitation. Problems can arise at each stage if there is an inadequate appreciation of the mineralogy involved and its effects on the treatment process. Modern image analysis systems now permit a more quantitative understanding of the mineralogy of an ore to be gathered. Where previously the metallurgist had to rely on qualitative information to guide technical decisions, it is now possible to give numerical estimates to the compositional and textural properties which govern the mineral concentration processes. Ore samples can be characterised according to modal abundances, mineral grain size parameters and mineral associations, all of which affect the liberation and concentration of the values. The paper will discuss the application of quantitative process mineralogy by considering a number of case studies. These include: ore characterisation to assist in exploration, assessment and mine planning; modal analysis of complex mineral suites to assist in the evaluation of ores, the deportment of values between products and the recovery or loss of these values; liberation analysis for ore testing, plant optimisation and performance monitoring; and characterisation of tailing to guide estimates of leachability, stability and rehabilitation options.

Jan 1, 1998