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By Leung L, Downey M

This paper presents an overview of a technology package developed by BHP for locating discontinuities in coal seams using an in-seam seismic (ISS) exploration technique. The technology package includes instrumentation, data processing software, field procedures, numerical modelling and interpretation know-how. The technology developed has proved to be highly successful; features such as faults and dykes, not detected by other methods, have been delineated. Using equipment specifically designed for underground use, surveys are carried out quickly and at low cost. More than 30 ISS surveys have been conducted by BHP in Australia. Substantial savings in production revenue have been realised in situations where ISS has identified mining conditions which would have impeded longwall operations. Case studies of several ISS surveys are described in the Paper.

Jan 1, 1987

By Lorenzen L

In South Africa, as in many other countries, the young engineering graduate is promoted quite soon to a management position where he uses less technical skills and more people-oriented skills. In the standard undergraduate curriculum for engineering, little attention is paid to the non-technical issues of the profession. An undergraduate course in management techniques cannot be a substitute for a MBA or Masters degree in engineering management, but can at least create an awareness of the practical problems facing the engineering manager. The aim of this paper is to provide an outline of such a course structure at the University of Stellenbosch. A survey is also presented on management training in the South African and Australian mineral industries. Feedback from students and graduates indicates that the fresh graduate does not fully appreciate the value of such a course until he/she achieves a position of responsibility after two or three years. Nevertheless, the management course appears to be successful in widening the perspectives of the engineer. As explained frequently in management journals, the technically oriented person (the engineer) has a convergent thought pattern, which could be in conflict with the more divergent thought pattern of the top, personnel or marketing manager. It becomes increasingly imperative for the young minerals engineer to be externally oriented instead of the traditional internal focus of engineering. The engineer should not only be aware of environmental issues in the technical design and operation of plants, but should also understand the inter-relationship between public relations, political pressures and environmental perceptions vis-d-vis technical facts.

Jan 1, 1993

Revised throughput rates, as a result of current mining methods and tight controls on mine dilution, have dictated a change in metallurgical philosophy at Renison Limited. Emphasis on throughput capacity increases has altered to a reduction in circuit complexity and operating costs. Extensive surveys of the gravity and cassiterite flotation circuits led to several plant modifications between August 1989 and March 1990. The coarse and fine gravity retreatment roughing tables were by-passed, the coarse gravity retreatment roughing tables were re-commissioned, the cassiterite flotation rougher capacity expanded and the gravity regrind cyclones re-configured.

Jan 1, 1991

By Szymanski J

Although efforts towards producing a `total quality rockfill product' have allowed cemented rockfill costs to be reduced considerably, there is still tremendous potential for further cost reductions. Cemented rockfill costs range from approximately $7 to $12 (US) per tonne of fill placed. Approximately 50 per cent of the rockfill costs are associated with cement costs. A large portion of the remaining 50 per cent is associated with labour and materials handling costs. Several Canadian underground mines utilise haulage trucks and/or conventional belt conveyors to distribute the rockfill. However, due to the restrictive nature of the underground environment, these current materials handling systems have limitations (ie spillage from trucks, dust from conveyors). The Sicon conveyor system (developed in Sweden) has considerable potential for replacing these current methods. The Sicon conveyor utilises a revolutionary approach - the conveyor belt is folded over upon itself (forming a tear drop shape) so that the transported material is completely encased within the belt. The Sicon conveyor's ability to negotiate very tight comers (without transfer points) makes the conveyor very appealing for underground mining applications. An analysis comparing the pros and cons associated with the Sicon conveyor system versus conventional materials handling systems will be presented in this paper.

Jan 1, 1995

By Hare S. M, Griffin P. T, O&apos

Chalcopyrite ore and converter slag treatment to produce copper concentrates is undertaken at the Copper Concentrator of Mount Isa Mines Limited. This concentrator was commissioned in May 1973, replacing the original No 1 Lead-Zinc Concentrator, for the processing of all chalcopyrite ore coming from Mount Isa Mine.Treatment of chalcopyrite ore at rates of up to 125 000 l/week is described here; the treatment of converter slag is described later.

Jan 1, 1993

By Wallman D

Since 1981 two single entry roadways have been driven at Ellalong Colliery for a total distance of 1 030 metres. They were driven at a height of 1.73 metres within the 3.7 metres thick Greta Seam using a Dosco In-Seam Miner (I.S.M.). Ventilation of the drivage was accomplish- ed by an exhausting fan in series with steel ducting and flexible ducting in the immediate face area. The air quantities provided at the face were more than adequate to comply with the requirements of -the auxiliary fan rules and the Coal Mines Regulation Act, 1912, as amended. The experience gained in these drivages demonstrated that the ventilation of long single entry headings can be practically and safely achieved using existing equipment.

Jan 1, 1983

The Rock Mass Rating (RMR) and Rock Mass Strength (RMS) classification systems for jointed rock masses are briefly reviewed, with particular reference to their use in slope stability studies. A correlation is provided between the results obtained from the two classifications and an equation is presented tentatively defining the RMR value for long-term stable slope angles. The validity of the equation is discussed in general terms in the context of slope stability problems commonly encountered in Western Australian open pit gold mines.

Jan 1, 1992

By Dawes C. A, Mitchell R. A

A process control strategy has been developed for the lead circuit of the lead- zinc concentrator at The Zinc Corporation, Limited (ZC), Broken Hill, Australia. The general aims of the control system were to produce a final concentrate with a zinc content below a certain limit and, at the same time, obtain the highest lead recovery possible. As presently arranged the system involves control of the cleaner feed mass flaw by cleaner diverter tray manipulation and control of xanthate addition based on per cent lead in feed. Generally this approach works well but for abnormal conditions such as very high or law pH the system requires further improvement.

Jan 1, 1983

By Boyd D. M

Minor magnetic anomalies which may be un represented on a magnetic contour map can be extracted from the original survey data and plotted by the described method to provide a rapid interpretation of the magnetic survey, provided that the data has been recorded digi- tally on magnetic tape. The example used comes from 40 kilometers south of Charters Towers, Queensland.

Jan 1, 1977

By Shoobridge PH, Firkin GR

The Imperial Smelting Process blast furnace (ISF) of the Sulphide Corporation Pty Limited zinc/lead smelter at Cockle Creek, New South wales, has in recent years greatly increased its consumption of low grade feed materials, and as a consequence has experienced periods of unstable furnace operation. Routine examination of production sinter, including softening characteristics and micro- examination, showed that the problems had been caused by an increasing silica content in sinter. The silica entered a low melting point glass phase containing calcium and lead oxides. The relative volume of this phase increased until it formed a continuous matrix in the sinter structure and this made the sinter more likely to soften at lower temperatures. Premature softening caused loss of operating stability in both the shaft and hearth of the ISr. The required sinter structure for ISF smelting was found to consist of a network of intermeshing, refractory crystals which provided skeletal strength for sinter lumps even after the glass phases had begun to soften and melt. With an understanding of the importance of microstructure and softening temperature of zinc/lead sinter and the progressive identification of those factors in sinter production which affect the microstructure, a significant improvement in stability of operations has been possible.

Jan 1, 1980

Draglines have been a significant part of world open cut mining since the early part of the 20th century particularly for the removal of overburden in the strip mining of coal. Since the mid-1960s draglines have played a major part in the large strip mining coal developments of Queensland and New South Wales.There are now over 60 large draglines operating in Australia ranging in size from 23 to 103 cubic metres bucket capacity, with digging depths to 60 metres, dumping heights to 50 metres and dumping radii to 100 metres. The application of these draglines has progressed through the uncovering of coal in shallow, single seam operations to deep multi-seam operations requiring a greater dependence on pre-stripping activities ahead of the dragline to remove overburden not able to be efficiently handled by the dragline.

Jan 1, 1992

The program, WASTRT 70, was set up specifically to handle the design of tunnel liners and underground structures where inter- action between rock and structure significantly affects the design. It may however be used for any mass/R.C. structure capable of being simulated by straight line elements between modes and with loading restricted to nodes. The analysis system adopts typical elastic/stiffness matrix methods. Two main mass/R.C. design segments are utilized (1) Design of section depth based on maximum required stresses and optimum steel/concrete ratios. (2) Design of reinforcement for a given section depth with concrete stresses given for mass and water code structures. Each design segment covers shear, minimum principal stress on ~ , heavy compression as per code (columns), heavy compression one-face steel (tunnel liners), tension and water code requirements for all moment/thrust/section depth ratios on rectangular sections.

Jan 1, 1976

By Dorricott M. G, McAllister J

This paper is concerned with the application of a probabilistic approach to the risk assessment of mining projects.In current practice, sensitivity analysis is the most commonly used deterministic approach of accounting for the uncertainties involved in mining project evaluation, while Monte Carlo simulation is considered to be the best probabilistic method available for the same purpose. The methodology of the approach proposed in this paper is as simple as that of sensitivity analysis. However, the results obtained can be more comprehensive than those obtained from Monte Carlo simulation. Various important statistical features, such as correlation and skewness, of the basic random parameters can be easily taken into account by the proposed approach. Example studies are demonstrated. Lotus 123 was employed for the associated probabilistic calculations.

Jan 1, 1992

The late 1960's and 1970's saw the initial development of the coal resources of the Bowen Basin of Queensland. The projects developed relied on large scale, open-cut operations using draglines for overburden removal and, in the majority of cases, project viability could be established based solely on those open-cut operations. Many of the mines developed in the 1980's have the same characteristics.Unlike these mines, the German Creek Mine has limited open-cut reserves at low overburden to coal ratios, and planning of the complex involved a large open-cut mine capable of developing early cash flow, with phased introduction of underground mining to replace open-cut capacity as the strip ratio increased.

Jan 1, 1985

By Parsons A. E

The application of known pelletizing tech- nology was successful in the agglomeration of zinc concentrate into pellets of minus 6mm siz- ing using fine zinc calcine and sulphuric acid as binder. Subsequent roasting trials conducted in a 0.3 m diameter fluid bed reactor, showed that the pellets satisfactorily withstood hot physical abrasion during fluidization. Fines generation was low and the pellet calcine was hard, possessing excellent handling properties. Results of laboratory scale static pellet sinter- ing tests showed conclusively that the deterior- ation in sinter physical quality experienced with fine calcine was not apparent when the calcine was added to the mix in pellet form. Based on the results of small scale exper- imental work, a one tonne per hour pilot plant was constructed and operated. Several thousand tonne of pellets were produced-for fluid bed roasting in Badische Analin and Soda Fabrik (B.A.S.F.) turbulent layer (T.L.) roasters previously designed for roasting iron pyrite concentrate. Continuity of the T.L. fluid bed roasting operations was achieved when the waste heat boilers were replaced with atmospheric coolers and thus eliminated the problems of gas flow restrictions. Sinter plant trials were conducted over a period of two weeks with the addition of pellet calcine to the sinter feed. Results showed a marked improvement in sinter plant performance, and as a result of better bed permeability, increased sinter production was achieved, with- out significant deterioration in sinter quality.

Jan 1, 1974

Blasting, particularly bench blasting, uses finite length cylinders of explosive close to two free faces. The rock to be blasted is usually intersected by a complex 3-D system of joints. To fully simulate a blast, a 3-D dynamic model is required. It is shown that the static stress distribution around a long cylinder can be reproduced by superposing the static stress distribution of a suitable chain of spheres. Thus, the dynamic results for individual spheres given by Favreau (1969) can now be substituted for the static results to give a dynamic model of the stress distribution around a long cylinder. Comparison of measured and computed waveforms show that the measured waveforms are much more attenuated and dispersed than expected. The consequences for explosive evaluation and design are Discussed.

Jan 1, 1990

By Moore A. J, Evans R

Blast vibration control and assessment techniques have been developed which supplement traditional charge mass scaling methods. The improved techniques, which can be used to predict air and ground vibration levels at the planning stage, and to assist in the control of blasting operations, have reduced the level of operating risk concerning blast vibration. In addition to such factors as charge mass, distance and blast vibration levels, these additional techniques take account of orientation of the blasting face, topographic shielding, wavefront reinforcement, and meteorological conditions. They have assisted in compliance with specified blast vibration levels for environmental licence and mining lease conditions, the reduction of blast vibration nuisance to residents in the area surrounding a mine, and control of building and rock structure response in adjacent areas on the mine lease area.

Jan 1, 1994

By Ward C. W

Conventional polygonal and block modelling techniques inadequately represent the grade-thickness distribution of some narrow shear and stratabound gold deposits. The polygonal influence of high-grade drill intercepts can result in overestimates of resource tonnages at high-grade cut-offs. Although block modelling methods provide grade smoothing and a better representation of structural continuity, the technique can lack precise definition of ore width. An alternative method known as Spatial Object Modelling (SOM) has been developed on MineMap software to overcome some of these modelling issues. This method does not rely on a uniform cell size and allows grade smoothing between resource intercepts in three-dimensional space. The SOM technique creates grade-thickness bars on regular, user-defined spacings which allow easy visual comparison of raw intercept data to the interpolated model. Model cell values are readily transformed into isopachs, isopleths and resource perimeters for reporting and mine planning purposes.

Jan 1, 1997

By P A. Grossman, J H. Rubinstein, M Brazil, D Whittle

Many ore reserves are harvested by a combination of open pit and underground mining methods. In these cases, there is often material that could be mined by either method, and a choice has to be made. The area containing this material is referred to as the transition zone. Deciding where to finish the open pit and start the underground mine is referred to as the transition problem and it has received some attention in the literature since the 1980s.In this paper, we provide a review of existing approaches to the transition problem encompassing: graph theory-based optimisation employing an opportunity cost approach, heuristics and integer programming. We also present a novel opportunity cost approach, that takes into account a crown pillar, and show how the new approach can be best applied through the unconventional application of an existing mine optimisation tool.CITATION:Whittle, D, Brazil, M, Grossman, P A, Rubinstein, J H and Thomas, D A, 2016. Determining the open pit to underground transition – a new method, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 731–742 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Schofield D, Denby B, Stout F, Moli A

This paper documents the development of a user-friendly computational program, which has been constructed to assist the mine ventilation engineer in the optimal design and operation of methane drainage ranges. In the past, many computer tools for ventilation engineers led to the development of `research systems'. These computer systems, although developed with the needs of the industry in mind were due to a combination of inexperienced programming methods and the availability of suitable user interface software not easily accessible to the practising engineer. Recent developments in computer hardware and software (particularly windows based graphical user interfaces) mean that engineers no longer need to dedicate large amounts of valuable time to become familiar with often complex items of software. The authors of this paper intend to demonstrate a practical system which successfully integrates complex mathematical models, an easy to use interface and knowledge based techniques. The graphical interface guides the user to draw on the screen a mimic diagram representation of the methane drainage network. The user is prompted, during the construction of the drawing, to input the information and data required by the calculation and knowledge based procedures. The computer program then calculates all of the flows, purities and pressures throughout the network. Given reliable measured data from an existing range a comparative analysis can be performed between the predicted and measured network flow data. A knowledge-based system may utilise this analysis to either update the operational status of the network or suggest either a reasoned maintenance or remedial strategy to improve the performance of the drainage system. The development of the OMEN project has been carried out at the request of the Midlands Group, British Coal Corporation, Edwinstowe. The system is about to be field tested at a number of mines. It is hoped that when this paper is presented that the system will be used at both Group and mine level.

Jan 1, 1995