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By Watt JS

The ash content of coal can be determined using radioisotope X-ray techniques. A number of overseas applications of X-ray techniques are described; however these suffer from the disadvantage of either not compensating for iron variations or, if compensation is used, using X-rays of low penetration with consequent sampling difficulties. Current Australian Atomic Energy Commiss- ion (AAEC) research on X-ray techniques is aimed at overcoming the limitations of these methods. The AAEC method involves making measurements proportional to mass absorption coefficients of X-rays in coal at two energies. Calculations and experiments with X-rays up to 35 keV have shown that ash content can be determined to about 1 wt.%. This work is being extended to higher X-ray energies to enable the technique to be used directly on a conveyor belt or in a hopper. Neutron techniques can be used to measure the concentration of specific elements such as carbon, hydrogen and silicon in coal. Their con- centration is correlated to the coal parameters of interest. Methods of moisture determination based on hydrogen measurement and ash determina- tion based on silicon and aluminium measurement are described. Energy content can be determined accurate- ly by analysing the carbon content of coal

Jan 1, 1978

By Crosby N. R

The design of mine openings and the assessment of their reserve are processes ihicl, require the routine manipulation of considerable amounts of data. A number of computer programs have been assembled to operate in a mini computer in order to provide some mechanical assistance for these processes. The system responds to plain language commands. which allows mining engineers to compute the reserves for a number of possible mining outlines, on an interactive basis. Methods of numerical analysis were used in preference to statistical or qeostatistical techniques.

Jan 1, 1977

With the progress of modern mining engineering, one of the features of which is the mining from greater depths and the hoisting of greatly increased loads, it becomes a matter of increasing importance that the engineer should be able to determinewith some degree of precision the character of the strains on the hauling rope. But a wire rope is a complex structure; it is made up of spirally-twisted strands, which in turn are composed of spirally-twisted wires, and it is not particularly easy to say exactly what happens when this "doubly-twisted structure is wound round a drum or over a pulley.. The difficulty has been generally evaded in ordinary practice by the simple device of adopting a large factor of safety for the rope-usually from 8 to 10-a factor which experience has shown is sufficiently large to cover the bending strains set "up when the rope is passed over pulleys of the sizes commonly considered appropriate.When, however, we add the stress due to the bending of the rope to the stress produced by" the direct pull, we find that the actual factor of safety is usually more nearly 4 than 10, and frequently the bending stresses in the rope are so large compared with the simple tensile stresses that their neglect may easily lead to disastrous results when dealing with problems a little out of the common run. Common Empirical Rules.-It is always "recognized that the bending of a wire rope round too small a pulley is likely to do the rope serious injury, but as it is desirable in ordinary winding operations to reduce the inertia of the moving parts to a minimum...

Jan 1, 1907

By T Laurencont, C Unger

The Mount Morgan minesite, located approximately 40 km SW of Rockhampton in Central Queensland, comprises 270 ha of unrehabilitated land which is the currently the major source of acid mine drainage run-off and seepage to the adjacent Dee River. Additionally, the minesite hosts an Open Cut Pit which contains 9000 ML of acidic and metal-rich water. In the absence of active management of water in the pit, there is a 50 per cent probability of an uncontrolled spill occurring in future years. The development of a contingency plan for management of overflow from the pit in the short term, has incorporated findings from numerous studies relevant to the Open Cut Pit including, but not limited to, water balance, contaminant source identification, toxicity testing, water quality profiling and limnological modelling, and estimates of probability of overflow. Extensive stakeholder consultation and peer review were also undertaken during the formulation of the contingency plan. The medium-term goal of lowering the water level in the pit to reduce the current high probability (50 per cent) of uncontrolled overflow to acceptable levels of risk is proposed to be achieved by a campaign of chemical water treatment. The treated water will be discharged to the Dee River, and sludge returned to the pit. The methodologies used for the selection and development of the water treatment process, that is proposed to involve treatment with lime, are described. Water treatment is the short- to medium-term component of a long range rehabilitation plan for achieving a negative pit water balance, and sustainable management of acidic water across the whole site. Achieving this ultimate goal will involve: reducing the inputs of water to the Open Cut Pit such that the annual water balance is zero or net negative, thus removing the need for water treatment in perpetuity; maximising, by surface rehabilitation works, the quality of run-off reporting to the Dee River; and minimising the volume of acidic seepage reporting to the seepage interception system. Possible strategies for achieving this long range goal consistent with overall site rehabilitation objectives are currently being developed and costed.

Jan 1, 2003

By Jones J. P, Arriagada J, Scherpenisse C. R

A recently-developed model is used as a tool to optimise the design of blasts used to create final walls in large open pit mines. The use of this tool has allowed present blasting practice and proposed designs to be evaluated to predict the likely extent of rock damage behind the final wall. The evaluation of the damage is dependent on the predominant local geology. Modelling of damage using the software allows the potential zones of rock damage to be evaluated under the following criteria: I . the extent of new fractures formed in the intact rock mass; and 2. the distance to which dilation and extension of existing discontinuities and pre-existing fractures will likely occur. The computer model has been used to examine present blasting practice and to estimate the damage induced by final and intermediate rows of blastholes. The results of current practices are presented in a visual form that allows simple comparisons to be made for any proposed changes in design. To confirm the predictions of the modelling, physical measurements are being undertaken at selected mines to quantify damage behind blast patterns, and experimental programs are underway to measure near-field vibration, or shock, levels. The computer modelling software is being used to qualify and improve the design of final rock slopes in large surface mining excavations, and to provide site engineers with well-defined design criteria for consistency in design. The model is seen to be just one of many tools which are being used in large open cut mining operations to gain an improved understanding of blasting and blast control.

Jan 1, 1995

By D Feng, G C. Lukey, J S. J, R R. Dagastine

An ongoing challenge in the coal industry is pyrite removal using the flotation method for fine particles. The use of a æseparation in frothÆ (SIF) technique to recover coarse particles of up to a few millimetres in size has presented a potential solution. However the commercial success of SIF is still limited due to the poor understanding of the separation mechanism. The particle floatability in SIF is determined by the constructive or destructive stresses resulting from the forces exerted by the particle on the bubble films. Hence, the surfactant properties and the mineral characteristics (eg hydrophobicity, shape, etc) are the key factors that control the interaction between the particle and froth. In the present work, the interaction forces between different particles (ie crushed glass, pyrite and coal) and a single air bubble are measured in a non-ionic surfactant solution (pentaethylene glycol mono n-dodecyl ether, C12E5) using an atomic force microscope (AFM). Experimental results show that the interaction is primarily dependent on the contact angle (ie the degree of hydrophobicity of the minerals). For crushed glass, the transition from repulsion to attraction was observed as the contact angle increased. As the concentration of C12E5 increased, the adhesion force was suppressed due to wrapping effect. For coal and pyrite with much higher hydrophobicity, long-range attraction was observed. The effect of shape factor was only visible at high surfactant coverage where sign of destabilisation became noticeable on the retracting force curve. These results provide a fundamental understanding of the direct interaction forces of a complex real system between an irregular particle of either crushed glass, pyrite or coal and a single air bubble. Theories developed for interpretation and modelling are thus far based upon the study of ideal systems of glass or polystyrene spheres and an air bubble and were incapable of explaining the interactions in complex real systems. The presented measurements were a first approach to the problem of real mineral-bubble interaction in flotation systems. Thus, the results can only best be interpreted semi-quantitatively.

Jan 1, 2005

A review is given of the development of the author's ideas on the relationship of ore occurrence to regional dislocations in the earth's crust, presently identifiable in particular areas as linear discontinuities in patterns of geological and geophysical data. Ideas originating from field observations in Broken Hill were developed in conjunction with three-dimensional kinematic deformation models which were devised to simulate rock structures, and to illustrate their response to assumed linear and planar movements at the scale of mine and regional geology. These led to the study of linear features in the pattern of Broken Hill district geology, and to the observation that the Broken Hill lode occupies a "cross-roads" position at the intersection of regional geological lineaments where they cross through and deflect the host rocks. A genetic association was therefore proposed. The recognition of significant regional lineaments requires special techniques and treatments of field data originally developed for the Broken Hill situation. The subsequent application of the work to the Western Australian shield revealed that known major nickel and gold deposits also occur where the host rocks are crossed by one or more regional lineaments. These lineaments were recognised as part of a continental tectonic pattern of major linear trends with which major ore deposits are associated. The ideas were later used in exploration leading to the discovery of the Olympic Dam deposit at Roxby Downs, South Australia, which is related to regional lineaments.

Jan 1, 1983

By Yaniuk DW

The sampling of non-ferrous concentrates from trucks and trains has long been carried out either manually or by automatic spears. Very little use has been made of conventional sampling systems for sampling concentrates at transfer points, or cross-belt samplers for sampling from the belt as the concentrate moves along the conveyor.Due to the high value of base metal concentrates and the often extremely heterogeneous nature of the material it is imperative that the sampling procedures adopted are accurate and precise. The basic principle that all particles in the stream have an equal opportunity to be included in the final sample is not fulfilled by accepted traditional concentrate sampling procedures such as the spearing of wagons, trucks or streams. This may lead to significant bias being introduced into the final sample.Consequently, the application of correct sampling procedures, either with conventional cross-stream samplers or the newer cross-belt samplers, is of prime importance.SGS Australia has recently installed a number of cross-belt samplers for the sampling of base metal concentrates both in Australia and overseas. The application of these samplers will be discussed with emphasis on the benefits of their use.

Jan 1, 1976

During induration of iron ore pellets produced from magnetite concentrates, there are many reactions occurring simultaneously. While the magnetite is being oxidised to hematite, carbonate fluxes are being calcined, leading to the formation of complex oxides. Calcination of fluxes and the formation of calcium and magnesium ferrites and silicates during the preheat stage can influence the magnetite oxidation process. As the calcination reaction proceeds quicker than oxidation at temperatures experienced during the preheat stage (700 - 1200¦C), the bulk flow of CO2 emanating from within the pellet should disrupt the diffusion of O2 to the magnetite reaction as the gas fluxes are similar in magnitude. This increases the time required for the oxidation of the pellet. Using an infrared rapid heating furnace, experiments were performed on heating individual magnetite green balls in an air atmosphere. These experiments showed that time played an important role in the extent of oxidation and calcination and temperature significantly influenced the initial evolution of high temperature phases such as magnesioferrite, calcium ferrites and calcium silicates. Understanding the kinetics of all these reactions for a particular pellet feed, and their interaction, is important for optimising the design of the induration furnace.

Jan 1, 2005

By Hinrichsen H. D, Rathburn D. R, Stieger W

The present situation in the field of iron ore pelletizing is briefly described with particular view of the Lurgi/Dravo travelling grate process. To meet todays pellet quality requirements with regard to physical and metal- lurgical properties it is often necessary to add basic fluxing materials. It has been de- monstrated that for certain ores, basic addi- tives provide a considerable improvement in fired pellet quality. The production of self- fluxing pellets is becoming increasingly attractive. One Lurgi/Dravo plant is now in operation and another is under construction which were designed for the production of self- fluxing pellets. Self-fluxing pellets may be considered as the primary or exclusive blast furnace burden and the installation of a sinter plant is not necessary if the pellet plant-can handle all in-plant fines. Reference is made to the first pellet plant utilizing iron ore concentrate, in-plant fines and basic flux. The use of solid fuel for pellet indura- tion is discussed because of the increasing prices and possible shortages of heavy oil and natural gas. Since there is a strong tendency to increasing plant capacities, the design fea- tures of travelling grate pelletizing plants for productions up to 6 million tonnes are Discussed.

Jan 1, 1974

By Finlayson E, Hilyard D, Francis G

Papua New Guinea's mainland is dominated by a foreland thrust belt, which can be divided into two zones. The "body" zone is floored by Palaeozoic granites and metamorphics of the Fly Platform (Tasman Orogen). Underlying the "tail" zone is Papuan Plateau, rifted from the Tasman Orogen during Coral Sea spreading, and believed to underlie the Papuan Peninsula and Papuan Islands region (D'Entrecasteaux, Woodlark, Misima, Sudest, and Rossel Islands). Thrusting began in the Miocene and continues today in the crust below the "body" zone. The youngest known thrusted rocks in the "tail" zone are Pliocene in age. Recognition of foreland thrusting has major implications for petroleum prospectivity of the Papuan and North New Guinea Basins, mineral exploration prospectivity, and geological terrane identification in PNG.

Jan 1, 1987

The microstructures exhibited by ilmenite in its association with other oxide minerals have been the subject of a number of papers, the most comprehensive of which is that by Ramdohr. The following observations in some degree extend his conclusions. They are based upon a study of about sixty specimens of "massive" ilmenite and titaniferous ores from a number of wIdely 'scattered Australian localities. Specimens of this character proved much rarer than was expected. The collection was gathered together through the generous aid of the University Geological Departments, Geological Surveys, and Natural History Museums of the several States of the Commonwealth, all of which contributed such specimens of local origin, as they possessed. Special thanks are due to Dr. E. S. Simpson, of Western Australia, who made available several highly interesting specimens, together with his...

Jan 1, 1938

This paper first describes the essentials of the slurry shield method and its achievements, then problems encountered during driving tunnels and their countermeasures, and finally shows problems to be solved in the future. The author works at Tekken Construction Co., Ltd. as a director. All the data cited are based on material gained from the slurry shield tunneling works undertaken by the said company. The mark, viz*, indicates that Tekken Construction Co., Ltd. has obtained or is applying for a patent in the U.S., Europe and Japan. 1. CONSTRUCTION RECORDS BY SLURRY SHIELD METHOD AND ITS PROBLEMS (1) Shield machines in the future should have the following characteristics; a. to be able to drive less cohesive soil b. to make no change to the ground water table level c. to make it possible to let people work in normal air pressure d. to cause less settlement at the surface To meet the above conditions various kinds of mechanical shields have been are tried, viz. limited air pressure type, rotary cutter with slit regulator, screw-discharge type, blind shield, etc. As far as the author knows, however, they are not 100% successful. Tunnels need their own accuracy in accordance to the usage. Both ease of driving

Jan 1, 1976

By Bailey S, Avraamides J

Laboratory-scale experiments were conducted in a mechanically stirred aeration vessel to determine the rusting abilities of aerated water in the presence of various catalysts compared to the industrially used ammonium chloride. The catalysts used were tartaric acid and citric acid, firstly by themselves, and then in later experiments mixed with ammonium chloride. From these experiments it was found that leaching of iron from reduced ilmenite in the presence of either tartaric acid or its sodium salt was much slower than in the presence of ammonium chloride. Citric acid or its sodium salt also give a slower rate of leaching than the ammonium chloride system, but citric acid and its sodium salt mixed in equal proportions produced a rate of leaching approximately twice as fast as the standard ammonium chloride system. When tartaric acid was mixed with ammonium chloride the leaching rate was found to be equivalent to the leaching rate of the same amount of ammonium chloride alone, thus indicating that tartaric acid made no contribution to the leaching in this svstem_

Jan 1, 1996

By Sengstock G. W, Spathis A. T

Benchmarks of mine equipment involved in the excavation process of coal mines would suggest that such equipment is not always operating at an optimum level. Dragline operations and truck/shovel operations rely on efficient use of their plant in order to maintain high mine throughput. The first process which affects the material to be excavated is the drilling and blasting process. Drilling and blasting delivers a fragmented material with a given disposition ready for excavation by mine equipment. As mine operators demand more productivity from their major excavating equipment, many sites are considering the use of productivity monitors to measure their outputs. Some of these productivity improvements will be directly related to the drilling and blasting process, so that as the monitoring systems improve, the opportunities to evaluate all drilling and blasting variables will also improve. This paper reviews current and newer methods for monitoring equipment productivity in mines. These include simple time and motion studies obtained by either manual timing of processes or by automated data collection equipment being adopted by the industry. Case studies for truck/shovel operations are discussed and the productivity improvements are compared with typical industry standards. These improvements relate specifically to parts of the load, haul and dump cycle and the potential for significant improvements are identified. Particular opportunities for drilling and blasting improvements are also presented.

Jan 1, 1995

Drag pick roadheaders and continuous miners have been applied in the coal mining industry for several decades, having replaced drill-blast methods as the primary means of excavating coal and coal-measures strata. The generally harder rock types associated with metalliferous mining have precluded the use of such machines in the past, however, developments in machine technology and increasing labour costs and environmental constraints suggest that there are now likely to be applications suited to the method. Metalliferous mining engineers are generally unfamiliar with the machines themselves and with the fundamental criteria controlling rock cuttability. This paper gives an introduction to the machines and the controlling factors.

Jan 1, 1987

By D Obeng, D Alexander

Over the past five years, commodity prices have been high and the focus of many plants has been æthe more metal the better, at whatever costÆ. In the recent economic crisis, the focus has shifted more to reducing the cost of production and operating at higher efficiency. Since 2002, JKTech has partnered with the Century mine in north-west Queensland to transfer technology and understanding through the good, bad and ugly economic environments, using methodology and techniques arising from research at the Julius Kruttschnitt Mineral Research Centre (JKMRC) and other research institutions around the world as part of the AMIRA International P9 Project. The JKTech studies were concentrated around the primary zinc circuit. During this period, Century expanded the primary zinc regrind capacity, installed additional scavenging capacity, installed and commissioned a Jameson cell for concentrate cleaning in the carbon preflotation circuit, and installed additional primary grinding capacity. Flotation circuit models were developed for each of the survey campaigns and enabled opportunities for further improvement to be identified, implemented and tested in the subsequent campaign.

Jan 1, 2009

By Sehic O. A

Geology can be the root of evil or a source of bliss; there is a choice; to ignore geology is at a mine's peril.Risk can be minimised and profitability maximised by the application of a detailed understanding of geology, alteration, structure, mineralogy, chemistry, fabric and texture.Geology is dynamic, not static.The impact of geology is pervasive.The integration of ore quality control with grade control is one strategy for improving the utilisation of both the mineable reserves and existing plant and equipment. Grade maintenance is but one constraint on the problem of how best to blend the ore. Other ore characteristics such as mineralogy, hardness for grinding, and pulp fluidity or density for slurry size classification can be included to explore alternative blending Strategies.

Jan 1, 1993

By Manlapig EV, Mackinnon IDR, Laudr DW

Orebodies at Ok Tedi contain a number of different fluorine bearing minerals. Some of these minerals report to concentrate and are responsible for the presence of the penalty element, fluorine, within the concentrate. Previous analytical work has tended to examine geological samples for content, rather than determine the metallurgical behaviour of the different mineralogical species. This investigation utilised X-Ray Diffraction combined with Scanning Electron Microscope / Electron Microprobe to identify the fluorine bearing minerals in flotation test products. Seven fluorine bearing minerals were identified, viz., talc, phlogopite, amphibole (tremolite and actinolite), sphene, apatite, biotite and clay. Talc was found exclusively in the skam ore type. Phlogopite and amphiboles (tremolite and actinolite) were found to occur in both skarn and porphyry ores, while sphene, apatite, biotite and clay were found only in the porphyry ores. Of the fluorine bearing minerals observed, only talc exhibited natural hydrophobicity to any significant degree. Phlogopite and the amphibole minerals were found to be hydrophillic, whilst the remaining minerals occurred in insufficient quantities to determine the flotation behaviour. Ok Tedi copper concentrate fluorine content prior to skarn ore treatment in the mill (typically 350ppm) was previously identified as deriving from phlogopite, while talc was believed to be the source of intermittent high concentrate fluorine contents when skarn ores were treated. This paper provides supporting evidence for this belief, and reports the nature of fluorine bearing mineral flotation behaviour.

Jan 1, 1997

Mining software packages are used extensively in industry for resource estimation as well as for mine design and operation. Research undertaken in the W H Bryan Mining Geology Research Unit at the University of Queensland has shown that modifi

Jan 1, 1994