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The major copper orebody at Mount Isa is being extracted at a rate of four million tonnes per year. The method used requires an equivalent rate of back filling with (mainly) cemented fill. There were three major incentives for developing this mining system. The first was the prospect of high ultimate recovery of the orebody. The target is 100% recovery. Also the proposed stoping layout appeared to offer significant advantages in development and production costs. Finally, extensive subsidence above the northern end of the orebody could have disturbed permanent surface installations and jeopardised a possible future open cut. The full implications of this ambitious strategy were not apparent in the early years. Now, after twelve years of production the benefits are being realised and they can be weighed against the costs. Probably the most interesting result which comes from this analysis is the significance of cutoff grades and dilution factors in balancing mining and filling rates.

Jan 1, 1980

By Lunt D

Arsenic is classified chemically as a metalloid. That is, it has properties intermediate between those of metals and non-metals. Like non-metals, it combines with many metals to form arsenides (eg arsenopyrite FeAsS, niccolite NiAs, sperrylite PtAs2), but like metals it forms sulphides and oxides (eg realgar AsS, arsenolite As203). Arsenic is distributed widely in the Earth's crust at an average concentration of 1.5 mg/kg and is present in more than 150 minerals.

Jan 1, 1991

By Pratt V, Davis K

Challenges facing middle management in the 1980's and beyond are not confined to business matters such as industrial relations, government and legal constraints, corporate takeovers, and commodity marketing. More particularly they deal with people issues and the interrelationship of corporate/ family relationships. There is a need for corporations to acknowledge the growing conflict between corporate/family roles being brought about by such matters as equal opportunity, double professional marriage partnerships, personal mobility and the increasing stress faced by managers as a result of current demands and expectations being placed on them. While the main responsibility for managing professional life as well as the relationship between professional and private life rests with the individual executive, corporations nevertheless have a major responsibility to assist these executives in this management process. Corporations in Australia are taking steps to address this situation but much more needs to be done. This was highlighted in the March 1985 "Middle Management" course with its associated Spouses Programme presented jointly by Australian Mineral Foundation and The Australian Administrative Staff College. Effective communication is at the heart of the matter but no amount of training on this subject will bear fruit unless there is an associated commitment by executives to improve the effectiveness of their communi- cation process both in their corporate and family roles.

Jan 1, 1986

By R Ayothiraman

Tunnel excavation may induce adverse effects on nearby existing structures/foundations in urban areas. Accurate prediction of tunnelling effects on pile foundations of nearby structures in the urban environment poses a major challenge during design. Several studies have been undertaken to understand the mechanisms of the soil-tunnel-pile interaction, which focused only on influence of tunnelling on nearby existing building and foundations. However, effect of pile loading on existing tunnels did not receive enough research attention so far. So it is essential to measure the response of existing tunnel-lining due to loading on newly constructed pile to assess to the safety against the additional forces/moment caused by pile loading and to evaluate the critical distance for the proposed construction of any structures from the tunnel location. This paper presents result of three-dimensional (3D) finite element analysis carried out in ABAQUS to investigate the effects of pile loading on existing tunnels embedded in cohesive soil. It is found that the effects on tunnel lining depend on horizontal separation distance between pile and tunnel as well as location/elevation of pile tip with respect to tunnel location.

Mar 8, 2011

By B Bonfils, P Lois Morales, C Evans

One of the main challenges for current and future mining and processing methodologies is to understand the characteristics of the rock so that its behaviour in one or more parts of the mining process chain can be predicted. Features such as rock texture, mineralogy or border complexity between minerals control how the rock behaves from the processing plant through to the final products, including tailings disposal and thus can affect the feasibility of the project from technical, economic and environmental impact perspectives. Understanding how the mineralogy and texture of rock affect its behaviour in mineral processing is a demanding area of research and is essential knowledge in predicting the processability of complex ores in different stages. This study aims to demonstrate that different types of relevant information can be extracted from a range of currently available analytical methods. However, this information can be used in a complementary way for building a more comprehensive rock characterisation at the microscale and better-predicting ore processing characteristics from the intact rock through to tailing disposal. CITATION: Lois Morales, P, Evans, C and Bonfils, B, 2018. Multisource rock characterisation at microscale for a better understanding of processing characteristics, in Proceedings Complex Orebodies Conference 2018, pp 44–48 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By Torabi S. R, Daly C. R

Wind blast is the sudden movement of air displaced by the massive collapse of roof rock in underground openings and is experienced as a high velocity flow of air through adjacent workings. The initial flow in the outbye direction is often followed by 'suck back', that is a reverse flow of air towards the newly created void. As part of the Wind Blast Project, undertaken by The University of New South Wales, Department of Mining Engineering, a physical model was constructed. One of the functions of the laboratory wind blast model is to provide insight into the dynamics of the interaction between the falling strata and the air being compressed below. During a collapse, some air is expelled into the surrounding roadways while the remainder penetrates towards the top of the roof elements. In this paper two aspects of the rock mass properties which influence the phenomenon are considered: - Flow paths through the falling roof element, ie the permeability of the roof element; - Bed separation prior to the fall which introduces a void above the roof element. A series of tests was carried out utilising the physical model in order to investigate the relationships between the flow of air through the simulated roadways, the variations in gauge pressure above and below the falling roof element, and the acceleration and terminal velocity of the latter, all as a function of the flow paths through the roof element and of the extent of the void above. The results of comprehensive tests using the wind blast physical model suggested that the time history of outbye air flow in the simulated roadway comprises two distinct phases. a) A primary phase, characterised by a high velocity flow of air which exhibits a peak and corresponds to the period during which the roof element is accelerating. The peak air velocity is related to the acceleration of the roof element. b) A secondary phase, characterised by a residual air flow of a lesser velocity than in the primary phase and corresponding to the period during which the roof element is falling at its terminal velocity. The velocity of the residual air flow is directly proportional to the terminal velocity of the roof element. In a monolithic collapse of a roof element it was shown that the presence of flow paths in the roof element increased the air velocity in the roadway in both the primary and the secondary phases. The presence of an air-filled void above the roof element, on the other hand, influenced the air velocity only in the primary phase by increasing the peak air velocity. The overall duration of the process was however decreased as a result. 'plug type' collapses, where roof failure extends to the ground surface, potentially generate the highest peak air velocities likely to be encountered during wind blasts.

Jan 1, 1995

Establishing the link between the solid, cold rock of dikes, sills, plutons, and lavas and hot, active magma chambers is the quest of igneous petrology. Differentiation of Earth, the diversity of the igneous rocks, and the spectacle of volcanism are ample evidence that magmatic processes are fundamental to our understanding of planet formation and evolution. Single gabbroic plutons, on the other hand, often show intricate and abundant evidence of the effects of crystal growth and sorting. It has not proven simple, however, to establish the basic principles of magmatic behavior leading to this crucial evidence. Because of their abundance, exposure, simple geometry, large range in size, and often straight-forward petrology, sills are excellent examples of the magma chambers. Physical and chemical processes operating in sills can be recognized that also routinely operate in many other bodies. Understanding the dynamics of sill solidification is essential to understanding the genetic links between lavas and plutons.

Jan 1, 1990

In the southern part of China, car-bonate rocks outcrop in large areas. Ka-rst develops owing to hot, humid climate and heavy rainfall. In deposits of coal, iron, bauxite, tungsten, tin and base metals exist karst formations within or near the mineralization zones. Three pro-blems should be solved in the mine cons-truction in karst region. The first is the drainage and safety control of karst groundwater. Different methods are used to cope with local hydrogeological con-ditions, e.g. drainage from surface by submersible pumps in wells penetrating groundwater seams; drainage from under-ground drifts which intercept groundwa-ter flow with clusters of holes drilled into karst aquifer or with vertical ho-les drilled from surface to the drift underground; cement grouting to block off channels or to seal a part of aqui-fer; groundwater pollution control; etc. With those measures many Chinese mines of tremendous waterflow were success-fully developed and valuable experiences were gained. The second problem is the stability of buildings deteriorated by surface subsidence due to drainage. The occurence and distribution of surface cavings by drainage were studied.

Jan 1, 1990

Lightweight polymer grids have recently been introduced to the mining industry. They are currently being used for roof and rib control, longwall shield recovery, safety guarding or barricade, highwall screening, internal reinforcement of gunnite/shotcrete applications, sub-base reinforcement, construction of steepened slopes, retaining walls, mine reclamation (i.e. erosion control, turf reinforcement), and in numerous mining waste related projects. These polymer mining grids utilize a strong, lightweight polymer, usually special grades of polypropylene or polyethylene. High tensile strengths are achieved by molecular orientation of these polymers in the manufacturing process. The first step in the manufacturing process is to extrude the polymers into thick continuous sheets. These sheets are then punched, and drawn into open grid structures. Aperture size and configuration are controlled by the geometry of the punched hole and the degree to which the grids are stretched. The drawing process is the key to the molecular orientation required for the tensile strengths. These long chain polymer molecules in their natural state have a random orientation. When stretched, the molecules are pulled into a parallel alignment, thus creating a lightweight product with tensile strength comparable to Steel.

Jan 1, 1992

By Gostylla W

The economic feasibility of controlled district cross-cut recirculation is examined in this paper with particular reference to the most important mine ventilation network parameters. An algorithm is developed to express the annual cost of recirculation which is then compared to the annual cost of conventional ventilation using the University of Queensland Experimental Mine as a case study. The concepts of resistance ratio and volumetric efficiency ratio are introduced and used to analyse the economic feasibility of controlled recirculation within a mine ventilation network.

Jan 1, 1988

By Borshoff J, Coles R

The Rum Jungle Uranium Province is lo cated on the western margin of the Pine Creek Geosyncline approximately 60km south of Darwin. Uranium was discovered in the Embayment area (Whites Deposit) in 1949, spurring active ex- ploration and leading to the discovery of the Rum Jungle Creek South Deposit in 1959. With the discovery of the Alligator Rivers Uranium Field, new criteria in the understanding of the controls for mineralization sparked a re- surgence of exploration activities in the Rum Jungle area. Uranerz Australia Pty. Ltd. (UAL) commenced exploration in the area in the late 1970's in joint venture and in its own right. Two domal Archaean granitic complexes, the Rum Jungle and Waterhouse Complexes, domi- nate the area. They are unconformably mantled by Lower Proterozoic sediments metamorphosed to middle to upper greenschist grade. The Lower Proterozoic sediments are unconformably over- lain by remnant blocks of Carpentarian sand- stone, generally preserved in downfaulted blocks. Over a six year period extensive geolo- gical, geochemical and geophysical programs were conducted to reinvestigate previous target areas and locate new prospective zones. Exten- sive shallow bedrock drilling showed that lo- cally the stratigraphic succession is quite variable and cannot always be divided into an ordered succession for correlation with groups and formations established by the Bureau of Mineral Resources (BMR). Deformational events resulting in intraformational recumbent folding and overthrusting also account for repetition of certain lithotypes.

Jan 1, 1984

By P N. Duan, Z G. Liu, M S. Chu, X X. Xue, B Liu, G J. Cheng, T Jiang, J X. Liu

High-chromium vanadium-titanium magnetite has not been exploited and made full use of on a large scale so far due to the immature utilisation technology and the reality that the utilisation efficiency of valuable metals still urgently needs to be improved. In the present paper, the isothermal reduction kinetics and mechanism of high-chromium vanadium-titanium pellets were studied at 800–1100°C. The mineral composition transformation of pellets before and after reduction was analysed by means of X-ray diffraction (XRD), and the microstructures were examined by scanning electron microscope (SEM) equipped with energy dispersive X-ray (EDX) to reveal the elemental distributions. The effect of reduction temperature on the volumetric swelling degree and cold crushing strength was also studied. It was found that reduction temperature has a large effect on the reduction rate of pellets, and the increase in reduction rate is more obvious in the range 1000–1100°C than 800–1000°C. The volumetric swelling degree of pellets increased with increasing reduction temperature, while the cold crushing strength decreased. The transformation of mineral species can be expressed as Fe2O3 ? Fe3O4 ? FeO ? Fe, Fe2O3·3TiO2 ? Fe3O4· (2FeO·TiO2 ) ? 2FeO· TiO2 ? FeO·TiO2, (Fe0.6Cr0.4)2O3 ? FeO· Cr2O3 ? Cr2O3 , and Fe2O3· VO/V2O3 ? VO. The apparent activation energy of the reduction reaction was calculated to be 44.3 kJ/mol, and the reduction rate is controlled by the combined effect of interfacial chemical reaction and gas diffusion through the porous product layer. The rate controlling steps were further studied by calculating the resistance percentages. The interfacial chemical reaction was found to be predominant in the initial reduction stage, with the percentage effect of gas diffusion through the porous product layer gradually increasing during reduction.CITATION:Cheng, G J, Xue, X X, Liu, J X, Liu, Z G, Chu, M S, Jiang, T, Liu, B and Duan, P N, 2015. Reduction kinetics and mechanism of pellets prepared from high-chromium vanadium-titanium magnetite concentrate, in Proceedings Iron Ore 2015, pp 349–358 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By W D. Rech, K W. Keskimaki

As an integral part of the conversion from rail haulage to conveyor haulage at Henderson, over six kilometres of drifting and several large complex openings were mined. The deepest of these areas was nearly two kilometres beneath the surface, bringing all of the challenges of rock stress and heat that come with mining at these depths. Though many mines operate at these depths, the development of the infrastructure necessary to support a 36 000 tonne per day caving operation brought some unique challenges to the development mining activity. The issues handled include: finding experienced staff for a æfast trackÆ development program; rock bursts and ground conditions; inflow of 50 degree centigrade water; acceleration of the project completion; large diameter raise boring and difficult muck handling.

Jan 1, 2000

By Chappell B

Backfill in the form of mine waste tailings has inherent problems associated with attaining adequate strengths upon placement. Fines are usually removed to ensure adequate drainage, which lowers the cohesive strength of the fill, leaving the fines to he placed in a tailings darn. Electro-drainage and electro-chemical grouting is examined to investigate its effects on densification and shear strength within a silty clay tailing having low permeability and shear strength. Two separate grouting mechanisms are observed for the iron and silica grouts used. Electro- osmosis is associated with iron grout that deposits within the tailing matrix under a converging pH gradient, and increases the permeability of the tailing. This process initiates cation exchange and causes cementing of the granular contact points between the clays. Electro-phoresis causes sodium silicate solution to deposit silica grout in the voids of the tailings. The resultant effect of these mechanisms results in an increase in cohesion, leaving the void ratio of the iron grouted tailings as it was but significantly reducing the void ratio of the silica grouted tailings.

Jan 1, 1998

By B Haase, R Saha

Conditional simulation (CS) has been extensively used in metal industry to assess uncertainty of geo metallurgical variables to build robust distributions around grade tonnages across different time horizons. Coal’s entry to nonlinear stochastic modelling is relatively new and this paper summarises the work done at BHP to enable its practical usage from production time frames to Life of Asset planning. CS in coal using Sequential Gaussian Simulation (SGS) is used to understand resource confidence around specific variables within pre-defined boundaries of spatially continuous domains for each coal seam. The variation between simulations for a given parameter reflects uncertainty. This paper demonstrates the use of CS to profile resource based upon agreed seam/parameter uncertainty thresholds which affect planning, forecasting, extraction and inform identification of key production risks and defining mitigation strategies. The end goal is to de-risk long-term plans by optimising infill data collection and improve stability in short-term planning through increased understanding of confidences locally rather than at global resource definition stages. The paper also briefly discusses the use of automated workflows and systems to minimise the time spent on the process to enable use in decision-making.

Mar 22, 2022

Geological. engineering is a field of engineering practice concerned with design and construction of excavations and structures in soil and rock masses. The role of geological engineering in mining practice is defined in this paper, and the scope of the various disciplines in engineering science and geoscience which support geo-engineering research is discussed. The current national research capacity in geo-engineering is considered, and current and future needs for geo-engineering research for mining practice are proposed. Education programmes to sustain the proposed level of research and its industrial implementation are Suggested.

Jan 1, 1986

By Barnett DW

Financial risk analysis provides the tools to examine the uncertainty of capital decisions in new mining ventures. This paper explores the methodology by which financial risks can be studied and quantified. The most commonly used risk evaluation methods, such as sensitivity analysis and discount rate adjustment, are presented as an introduction to a more comprehensive discussion of stochastic methods of discounted cash flow analysis using Monte Carlo sampling. The discussion is illustrated with examples of a stochastic discounted cash flow. The advantages of Monte Carlo sampling in risk analysis are discussed together with its problems, particularly those originating from the correlation amongst the variables that determine the economic output of a mining venture, and the difficulties created by insufficient data, imperfect knowledge and complexity. The paper also surveys the most commonly used software used in risk analysis.

Jan 1, 1994

By P Hogan, M Wells

Reflectance spectroscopy has become an established technique for mineral exploration and ore characterisation. However, there are few reported cases where the technique has been applied to the Hamersley Province channel iron deposits (CID). The Bonnie Creek CID, located ÿ140 km north of Newman in Western Australia, represents one of a number of CIDs recently discovered in the Hamersley Province. Reflectance spectroscopic analysis using the CSIRO HyLoggerÖ automated scanning system, in conjunction with X-ray diffraction and compositional analysis, was used to characterise and map the ore and gangue mineralogy in CID drill core. Using CSIROÆs spectral mineral characterisation scripts, it was possible to map the downhole distribution of the Fe-oxide abundance, hematite:goethite ratio and the gibbsite and kaolinite abundance. Spectral estimates of kaolinite abundance were found to be closely related to loss on ignition measurements at 650¦C and the spectral kaolinite abundance index provided a reliable estimate of the total weight percentage Al2O3 content. In addition, downhole HyLoggerÖ scanning of diamond drill core reliably mapped the distribution of kaolinite as supported by coincidentally elevated contents of alumina and silica. Furthermore, spectrally-derived estimates of iron oxide abundance were well related to assayed Fe wt per cent contents and use of the spectral iron oxide mineral index mapped the distribution of the goethite:hematite ratio, and demonstrated that material logged as high-grade ore in the Bonnie Creek CID was predominantly goethite-rich.CITATION:Wells, M and Hogan, P, 2013. Bonnie Creek channel iron deposits ore mineralogy - insights using the HyLoggerÖ technology, in Proceedings Iron Ore 2013 , pp 321-328 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

A new approach to resource estimation at the exploration stage is emerging, based on the application of simple software techniques. The techniques combine the power of interactive graphics with proven database, analysis and estimation tools. With effective use of these tools the geologist now has maximum chance of deriving a reliable structural and grade model from the limited exploration data. Unlike cutoff-based polygonal methods, the resultant geological model can immediately be used to evaluate any economic scenario.These modelling techniques are embodied in MINEX-3D, an Australian software system. With the emergence of the 386-based PC and high resolution (VGA or better) graphics, MINEX-3D makes the power of this new 'desktop geological modelling' accessible to most exploration geologists.

Jan 1, 1990

By Stewart WJ

Australia's first offshsore well was spudded in on 27th December 1964 and resulted in the discovery of the Barracouta gas field. Further exploratory drilling led to the discovery of the Marlin gas field in December 1965, the Kingfish oil field in April 1967 and the Hblibut oil field in June. 1967. In September 1968, a small oil reservoir was found in a sand below the main Barracouta'gas reservoir. The Snapper gas field was discovered in May, 1968 Information on exploration activities associated with the discovery of oil and gas in the Bass Strait area may be found in the paper, "Exploration in the Gippsland, Bass and Otway Basins, Australia" by B. M. Hopkins. _ Development of the commercial fields is being undertaken on an equal participation basis by Hematite Petroleum Pty. Ltd. and Esso Exploration and Production Australia Inc. Esso Standard Oil (Australia) Ltd. is responsible for the design, construction and operation of the production facilities.

Jan 1, 1970