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By Grouhel P

Blasting performance is directly related to the characteristics and efficiency of the explosives used. The selection of the correct explosive for particular blast conditions and objectives depends on the ability to characterise the performance of individual explosive products. Techniques have been developed by the JKMRC to measure explosive performance and assess the impact of explosive performance on blast results. Studies conducted at a number of mine sites have shown that different types of explosives perform quite differently and that the performance of any particular explosive can vary significantly. The principal causes of these variations have been identified and detailed blast monitoring techniques, including the analysis of muckpile fragmentation and shape, have been used to quantify the effects of explosive performance on blast Results.

Jan 1, 1990

By Boger D. V

Two industrial case studies in which detailed investigation of the flow behaviour of mineral slurries is used to assess the feasibility of pipeline solid transport are described. The first example deals with the pumping of highly concentrated bauxite tailings to disposal, while the second exam- ple examines the possibility of transporting high-density Victorian brown coal slurries which previously has been thought as uneconomical. It is demonstrated that these typical solid handling problems can be solved by a good understanding of the rheology of suspensions.

Jan 1, 1989

By Crapp C. E

The Collinsville Coal Measures consist mainly of arenaceous sediments but indude eleven named coal seams. The Formation outcrops around the northern end of tbe Bowen Basin where it attains a thickness of 700 ft. in the Collinsville-Scottville area and overlies Lower Bowen Volcanies with angular unconformity. Most of the members in the Formation thicken basinwards. The regional dip is about 8 degrees. The Formation thins southwards and does not occur south of the Bowen River on the eastern flank. On the western flank it is represented by 60 ft. of barren sandstone at the limit of our mapping, 12 miles south of the Bowen River. Two seams are mined, the Bowen and the Blake; coal from the former produces high grade metallurgical coke, and the latter seam is mined for steaming coal. Where mined, the seams are about 20 ft. thick. The coals are of medium volatile bituminous rank and the lower coals are of higher rank than those above them.Reverse faults striking across the Coal Measures have been delineated and the existence of areas of intrusive rocks has been established. Intrusions rose up fault planes and, as felspar porphyry sills, selectively intruded coal seams, decimating reserves of coalavailable for mining. One sill, in the Blake Seam, attains a known thickness of 115 ft. Because the distribution and thickness of the sills is rarely predictable, density of drilling has been greater than in most coalfields.INTRODUCTIONThe assemblage of sediments occupying the northern portion of the Bowen Basin (Fig. 1) may be divided into four formations of Permian age:The Upper Coal Measures (U. Bowen)The Middle Bowen Marine Beds (M. Bowen)The Collinsville Coal Measures (M. Bowen)The Lower Bowen Volcanics (L. Bowen).Of these, the Upper Coal Measures and the Collinsville Coal Measures are known to contain coal seams of workable thickness.

Jan 1, 1960

Instantaneous outbursts of coal and gas have occurred in Australia in the Sydney Coal Basin since 1895 and in the Bowen Coal Basin since 1954. The largest has been about 500 tonnes of coal and so their magnitude and character have not approached those experienced in some other countries. The occurrence of CO2 with some Australian cases provides some similarity with the worst affected areas in France and Poland.The proneness of seams depends on coal rank and seam gas composition, among other factors. The proneness of places depends on depth, structure, intrusion, tectonism and other factors affecting the geometric, physical and chemical uniformity as well as details of mining. As a phenomenon due to gas and stress, prevention can be achieved by relief of high gas and/or stress condition. Alternatively, controls can be applied to render mining safe for personnel. Unfortunately day-to-day prediction is not widely and reliably achieved to allow selective use of prevention or control. The initial rate of desorption is the most promising day-to-day indicator.Various researches include gas conditions and parameters, stress and failure conditions and parameters, coal variables and geological variables in relation to prediction, prevention and control. Some assistance in research may derive from study of analogous phenomena of instantaneous outbursts of salt and other rocks and gas. It is concluded that in the Sydney and Bowen Basins, any coals with less than 30 per cent Volatile Matter (VM) ash free dry (afd) at depths over 200 m could be prone. Proneness increases with depth, with lower volatile content, with geological disturbance including faulting, intrusion and recent tectonics, with increased CO2 in seam gas, with narrow work and with other factors. Much more research is needed.Unfortunately outbursts are needed too, to provide the research with realistic data. With the problems of mechanism and prediction still being unsolved much research remains to be done. No present aspect of research is satisfactorily resolved.

Jan 1, 1983

The evolution of the Oaky Creek mining complex provides a good example of the mining cycle in practice. Oaky Creek has been innovative in its choice of mining methods, with virtually the full range of coal mining methods having been used as workings have progressed down dip. The history of the mine is traced through its development (and ownership changes), progressive selection of mining methods as depths of cover to seams being mined have increased, and rehabilitation. This allows the different mining methods to be described and illustrates the concept of æwall-to-wall miningÆ.

Jan 1, 1998

By Schoning W. L

Ore deposit models form the basis for numerous other economic decisions in the mining process. The success of these economic decisions therefore depend directly on the accuracy of the ore evaluation process. The Geology Department at the Sishen Iron Ore Mine is responsible for the generation of a reliable geological computer model of the rock material with predicted grades. This information is then utilised for further ore reserve calculations, mine planning, production scheduling and grade control. Owing to a very complex geological orebody, grades and beneficiation characteristics differ significantly from sample to sample. This means that ore evaluation is a difficult process and great reliance is placed on computer techniques. In 1993, preparation for the ISO 9002 quality certification of the mine motivated the Geology Department to hold formal `problem solving' sessions in order to identify and revise problem areas in operating

Jan 1, 1995

By D Thomas, B Gallagher

Valuable data for geotechnical interpretation and integration into effective Australian underground mine planning may often be available, yet is not always fully appreciated or utilised, particularly in the early stages of mine planning or in due diligence studies. There may be considerable benefits associated with early prioritisation of geotechnical evaluation and impact on mine planning. Unidentified, misinterpreted, or ill-defined adverse geological and related geotechnical resource characteristics can pose significant business risk to underground coal projects and operations. Preliminary resource definition in the early conceptual mine planning stages attributes significant focus (entirely warranted) on resource quality and structural geology constraints. Yet detailed geotechnical data analysis and interpretation, which may have a substantial down stream impact and sensitivity with respect to future mine planning strategies, at times is given lower priority, or scoped and resourced in the later stages of a bankable feasibility study. Through extensive mine planning experience and observation of downstream process impacts, it has been found there is often data available for geotechnical analysis that does not readily stand out or is not adequately understood or utilised, available at the early (conceptual) stages of mine planning. Part of the issue may be that exploration geologists are not necessarily experienced geotechnical engineers and do not necessarily recognise or understand all important parameters. Subject to appropriate application of experienced professionals data can be manipulated to provide key geotechnical hazard assessment at minimal cost, and provide a framework for understanding and optimising the mine planning process. Although there is no single prescribed strategy for resource evaluation from a geotechnical perspective, potential business risks and mitigation approaches can and should be adopted at the conceptual mine planning stage. There has been a recent focus in the metals industry to provide a reporting framework for geotechnical classification of mining projects. This paper outlines the strategies and gives examples of key analyses adopted in mine planning and discusses the relative merits of adopting a reporting framework as a tool for geotechnical classification in mine planning.

Jan 1, 2005

By Borshoff J, Von Pechmann E

The uranium mineralization in the White's East area of The Embayment is hosted by Lower Proterozoic schists of the Masson Formation which have undergone polyphase de- formation and upper greenschist metamorphism. Significant mineralization is also present in apatite rocks. The ore zones occur near an unconformity with overlying Middle Proterozoic sandstone and breccia conglomerate. Kink breccias and fracture systems related to post Middle Proterozoic reverse faults are the con- trols for mineralizing fluid migration. Pitchblende is the main uranium mineral and it occurs as fine disseminated grains, fibrous webs, clusters composed of botryoidal aggregates and locally as veins. Two genera- tions of uranium mineralization are present. The first generation (pitchblende I) occurs as fine grained inclusions within chlorite II, and the second (pitchblende II) as hydraulic fracture networks and massive veins intimately associated with sericite-hematite-chlorite III. Two hydrothermal alteration phases have affected both Lower Proterozoic and Middle Proterozoic sequences. The most extensive alteration mineral is chlorite, of which a number of varieties has been identified. Mg-rich chlorites are generally associated with the first phase alteration assemblages and are commonly replaced by hematite, seri- cite and Mg-Fe chlorites in massive pitch- blende zones. Other alteration minerals in- clude tourmaline, apatite, talc, quartz, magnesite, graphite, pyrite and rutile.

Jan 1, 1984

Slope stability is a critical safety and production issue for open cut mines. The æslope stability radarÆ has been developed to remotely scan a rock slope to continuously measure the movement of the face. The system can detect and alert movements of a rough wall with sub-millimetre precision, and with reliability and resolution. The advantage of the slope stability radar over other monitoring techniques is that it provides full area coverage without the need for mounted reflectors or equipment on the wall. In addition, the radar waves adequately penetrate through rain, dust and smoke to give reliable measurements, 24 hours a day. The measurement technique is tolerant of vibrations and overcomes the need for a highly stable footing required by traditional surveying systems, making it easy to move from one location to another. The system is self-powered and designed for minimal maintenance. Radar displacement images, co-registered with digital photography images, are transferred from the radar site in the pit to the mine office via a radio telemetry link. Custom-written software provides mine managers and geotechnical engineers with a complete picture of slope movements over defined time intervals. The time-history of the movement of any selected points or regions on the slope can also be displayed. Also provided is the ability to set movement thresholds that will trigger alarms at the radar site or mine office. The system has been used at numerous coal and metalliferous mines in Australia, and has provided real-time monitoring of slope stability during active mining operations. More than 20 rock wall and spoil failures have been captured by the system, and on every occasion adequate warning was provided to mine operators. The high level of movement precision and broad area coverage of the rock face provides a better understanding of the geodynamics, which leads to extra warning time. This technology enables a radical change in the management of risks in open cut mining operations.

Jan 1, 2003

By Bond W. F, Sharry P. V, Onley P. G

The use of Decision Analysis is becoming more widespread in industry as a whole, and there is considerable scope for its application in the mining industry. Wherever decisions have to be made, whenever risks have to be taken, whenever uncertainty exists or whenever judgements have to be made, then Decision Analysis can be used. In the mining industry we daily make many decisions involving risk, uncertainty and judgement. Expansion and diversity will only increase the need for balanced decision making techniques. This paper seeks to describe the history and principles of Decision Theory, and to illustrate the various modelling approaches using three fictitious yet realistic case studies. Decision Analysis logically integrates the quantifiable and seemingly non-quantifiable aspects of a decision problem into a coherent, explicit and rational solution. It also allows the decision-makers to see the full impact of each variable or uncertainty, and hence focus on the key aspects that influence the solution.

Jan 1, 1996

By Baafi EY

Open cut mining in Australia is facing the greatest challenge in its history in attempting to compete not only with other operations internationally, but also with underground operations domestically. Most flat dip and shallow depth surface-mineable coal reserves have been depleted during the last two decades and new open cut operations must extract deeper coal deposits. As open cut coal mines move into deeper areas and the stripping ratios increase, the relative cost of overburden removal also increases. It therefore becomes even more important to design the mine around the optimum overburden removal scheme. The deeper mines are usually multi-seam operations with a more complex geology and with more geotechnical and hydrological problems. Deeper mines are subjected to greater problems requiring more detailed mine planning and design, such as selection of the optimum mining method and pit layout. In planning and design of such operations, the number of alternative methods which need to be considered is consequently greater.Dragline productivity and its stripping capabilities are directly affected by the selection of digging method, strip layout and pit geometry. Every mine has a unique combination of geological conditions. The operating methods that work well at one mine may not necessarily work at another site. Selection of an optimal stripping method, strip layout and pit geometry for a given dragline must be considered with respect to the geological conditions of the mine. With increasing geological complexity of Australian strip mines, it is becoming more important to use sophisticated techniques such as computerised mine planning methods to assist in optimising dragline operations.

Jan 1, 1998

By Rowley M, Bradford P

Plutonic Resources Limited (formerly known as Pioneer Mineral Exploration Limited) delineated, developed and operates the Plutonic Gold Mine located 180 kms northeast of Meekatharra, Western Australia. Gold mineralisation was discovered in the Marymia greenstone belt by Great Central Mines NL (GCM) in 1988. There was no previous, recorded gold mining activity in the area. In May 1989, Plutonic Resources Limited (PRL) entered into an agreement to acquire a 51 per cent interest in the three Mining Leases containing the Plutonic deposit from GCM. Subsequently in December 1989, PRL acquired the remaining 49 per cent interest in the Mining Leases. PRL and GCM are also involved in a 51:49 regional joint venture on extensive Exploration Licences in the vicinity of the Mining Leases. Following due diligence validation, reserve delineation and testwork, a feasibility study was undertaken in conjunction with JR Engineering Services, which led to the financing and development of the project for operation in August 1990.

Jan 1, 1991

By Vynne J. F

Drill monitors for rotary blasthole drills have been available to the mining industry since the 1970s. The early monitors were pen strip chart recorders that were developed for the oil drilling industry and adapted to mining. They recorded drilling parameters such as depth, pull-down pressure, torque, RPM, and hailing air pressure. While these recorders could generate a large volume of paper, the amount of useful data was minimal. The data was not summarised and required an engineer to interpret the chart traces. Being a mechanical recorder, the devices were also susceptible to frequent failures. Modem electronics, and the development of the personal computer and its associated software have radically changed the type of instrumentation that is now available for blasthole drills. Perhaps more important is what can be done with the data. The PC allows the logged data to be analysed, summarised, and a variety of reports to be generated. The reports can be customised to meet the specific requirements of the mine and reduce the amount of time that is required to interpret the data. There is also an increased awareness in the mining industry of the importance of production drills. Blasthole drills have typically been the piece of production equipment that received the least amount of attention in a surface mine. Management focussed on the trucks and shovels or draglines. This situation is changing, and therefore the benefits that can be derived from monitoring drill performance are being recognised. Potential economic benefits of installing drill monitors have been documented in previous papers (Peck and Vynne, 1992). Mines are finding that pay-back periods of less than twelve months and rates of return in excess of 30 per cent are not uncommon. These benefits include the following: 1. Reduced overdrilling; 2. Increased rate of penetration; 3. Helping to locate coal seams; 4. Identification of weak and strong zones; 5. Reduce geophysical logging; 6. Optimising blasts; 7. Improved fragmentation and diggability; 8. Decreased coal dilution; 9. Increased bit life; 10. Reduced maintenance costs; 1 I . Improved accuracy of data and reports.

Jan 1, 1995

By K S. E, S C. Parker, T K. Kundu

Understanding the fundamental principles governing the reactions at surfaces has always been the goal of theoretical surface science. The atomistic simulation techniques have been used to calculate the surface structures and the stability of quartz and wollastonite, and their adsorption behaviour in the presence of molecular and dissociative water, and the two widely used collector head group molecules of methanoic acid and methylamine. The dissolution behaviour of wollastonite has also been modelled. The calculated surface energy, hydration energy and reaction energy values have been examined and discussed in the light of flotation literature. These studies have given an insight into the interactions at atomic level, which indicate that modelling techniques should be capable of predicting the adsorption behaviour and to design the selective collector molecules, which is of central importance to the mineral processing technique of flotation.

Jan 1, 2005

Direct smelting of copper in a single vessel has long been the extractive metallurgist's dream. Such a process offers the important alvantage. of (i) maximum use of the energy available from oxidizing the sulphur and iron of the concentrate: (ii) restriction of SO2 emissions to a single constant-strength source; (iii) minimum materials handling and (iv) elim-ination of at least one process step. Extensive developmental work was carried out in the 1960's and 1970's to implement such single-step processes. Some of the processes reached the prototype stage and it appeared that copper smelting technology was on the thresthold of a new, efficient, minimum-pollution era. Since that time, however, the forward thrust has slowed and single-step copper smelting is still a process of the future.The paper describes the potential advan-tages of single-step smelting; its history and current status; and the reasons why it has not been adopted industrially. It concludes that the potential benefits of single-step smelting are powerful and that many of the difficulties encountered in the 1970's will be overcome in the 1980's.

Jan 1, 1985

By Weller K. R, Trahar W. J

The Mount Lyell Company treats some 2.3 million tonnes of ore annually, mined from a number of orebodies on the field. Blended ore is essentially a quartz-sericite schist containing about eight per cent of pyrite and three per cent of chalcopyrite. Four-stage crushing and two-stage ball milling are followe by selective flotation for copper. Pyrite is recovered from the coarse fraction of dopper circuit tailings. A detailed survey involving examination. of 82 samples provided information on the size- by-size behaviour of the principal ore constituents throughout the grinding, copper flotation and pyrite flotation sections of the circuit. Results for the copper and pyrite flotation sections are presented in the paper, and it is shown that over half the copper reporting to the final tailing (5% of copper in the feed) is plus 100 microns and that the major pyrite loss is in the desliming cyclone overflow. These data proVide a basis for assessing potential methods of circuit optimisation.

Jan 1, 1977

By S C. Bhowmik, R Gupta

This paper presents the ventilation problem faced by Jaduguda uranium mine, operated up to a depth of 905 m. The first two stages of the mine workings are up to 555 m, which are nearly exhausted. The third stage of the mine is from 555 m to 905 m and presently most of the stopping and development activities of the mine are carried out in the third stage. The total available intake quantity in the third stage was only 21 m3/s. As a result, the mine was facing a radiation hazard. The different instruments and the methods used for monitoring of radiation levels are also presented in the paper. It was observed that the average individual effective dose (external + internal) of radiation workers in Jaduguda mine increased from 6.93 mSv/y in 1995 to 9.5 mSv/y in 2001 and during this period the average individual effective dose of mine workers of the world was less than 5 mSv/y. Keeping this problem in view, a detailed ventilation investigation has been carried out in this mine. Initially the requirements of intake air quantity have been assessed by carrying out field investigation in different stopes and it was found that the third stage workings require nearly 100 m3/s. A detailed ventilation survey has been carried out in the total ventilation network and a basic ventilation model of the mine has been prepared. Different alternative schemes for effectively ventilating the third stage workings of the mine were simulated and a set of recommendations were made for implementation. The recommendations were partially implemented in 2002. As a result the total intake quantity to third stage workings increased to nearly 70 m3/s and the average individual effective dose (internal + external) of mine workers came down from 9.5 mSv/y in 2001 to 6.65 mSv/y and 6.60 mSv/y in 2002 and 2003 respectively. The implementation of remaining recommendations is in progress. Finally, a mathematical model has been formulated from the first principle for predicting air quantity requirements in cut and fill stopes in uranium mines and this model is being validated for further use.

Jan 1, 2005

Reliable predictions of the long-term water quality and water level fluctuations in a final void are vital if mine operators propose to decommission final voids in open cut mining operations. The catchments feeding final voids typically comprise a large proportion of coal placed or re-shaped spoil piles. Spoil piles from open cut coal mining operations have distinctive hydrological characteristics, which result in unique run-off behaviour. There is a need to understand the nature of spoil hydrology processes in order to predict the long-term hydrological behaviour and water quality responses of such systems. Preliminary estimates indicate that it may take 20 or more years for a void to flood. It is impractical for mine owners and operators to wait until long-term hydrological and water quality conditions have been established in a void, before reaching agreement with regulators about mine closure conditions. Reliable simulation of the long-term water quality and water level fluctuations in a void are therefore. The adoption of an agreed modelling approach and sharing of results from field data programs could result in the establishment of a database that could be used, with regulatory approval, for assigning parameter values, without the need for a specific data collection program for every individual void. Industry and regulators should agree on the model adopted for predicting post-closure behaviour of spoil/void systems. This will require reliable, robust methods for field data collection. This paper describes the field monitoring, data collection, model preparation and simulations undertaken over a three year period for Australian Coal Association Research Projects (ACARP) Project C7007. It presents the findings of that research, and provides comment on aspects of the project that were undertaken well and on aspects that could have been done better. Limited data is presented in this paper due to confidentiality arrangements with the relevant mine sites.

Jan 1, 2003

By Gang C, Changyi S, Liangde G

Geophysical and geochemical methods and techniques for gold exploration and their applications in China are summarised in the paper. Some case histories are also presented. The effect of prospecting for gold deposits using these methods is well illustrated through these examples.

Jan 1, 1997

By Mendeckl A. J

Anglo American Corporation has always viewed technological development as vital and as such has placed research and the implementation of new technological practices high on its priority list. Support is given to a number of research institutes but a significant degree of reliance is placed on in-house research carried out at individual companies and at the Group's main laboratory complexes. The Corporation's interests are diverse with advanced practices and innovative technology ranging from new battery technology with wide application to deep level shaft technology with very specific application. In this paper, we aim to concentrate on a particular system developed primarily for use in seismically active deep mines. The system has proved to have far wider application and has the potential to be further enhanced to meet the needs of users across a broad range within the industry and even beyond. As the nature of this conference is to inform delegates of advanced mining practices, we should simply mention that we could have talked on subjects relating to the advances made in deep level winding technology including winder drive and brake control to alleviate dynamic rope loads, shaft steel design for high pay load high speed winding and shaft safety systems such as slack rope devices and moving lip loading facilities to cater for rope stretch. Other areas of interest relating to refrigeration using ice technology or non-explosive rock cutting using diamond wire or saw technology could also have been of interest. As the South African gold mines become deeper and the problems associated with depth become more acute, answers had to be found and systems developed to cope with very high rock stress and the related seismicity. The fundamental understanding of the behaviour of the rock mass has always been important but became critical on our mines to ensure the safe extraction of the orebody. Basic research into and the application of physics, applied mathematics, seismology, rock mechanics, electronics and computer technology have helped us to develop the Integrated Seismic System - Integrated because of the system's abilty to monitor seismic and non-seismic sensors simultaneously and because it encompasses data acquisition, processing and interpretation into one system. The system which is in use at all our gold mines has found application not only in South Africa but also in such locations as Australia, Chile, Canada, Europe and Japan. A highly motivated team of scientists under the leadership of Aleksander Mendecki developed the majority of the hardware and software needed for the system. In essence, the system allows us real time monitoring of energy release and stress transfer data that with the aid of modern computers is turned into useful information. The information so obtained has allowed us to improve our mine and extraction designs to minimise the inherent hazards. The system has proved to be an extremely useful management tool as substantiated by the demand for the product. The paper is intended to convey to the reader the technical concepts and the presentation is intended to demonstrate the usefulness of the system.

Jan 1, 1995