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By Edwards A. B

Re-opening of the old Proprietary mine has provided new exposures of the system of uralite dolerite dykes observed in 19110 by the Geological Sub-Committee of the Scientific Society of Broken Hill. The newly exposed dykes have been invaded and replaced by the massive ore, with development of manganese garnet and biotite adjacent to the sulphides. A similarly altered dyke in massive ore has been encountered in the North Broken Hill mine.The textures of the unaltered portions of these dykes indicate that they have not been affected by the intense regional metamorphism that has recrystallized the other rocks of the area. Moreover, in mineral composition and textures, in chemical composition, and in cross-cutting relations, they are so similar to the uralite dolerites of the district which post-date the folding and metamorphism of the Broken Hill area, that they must be regarded as typical members of this suite of post-metamorphic dykes.The invasion and replacement of the dykes by the massive sulphide ore, and their metasomatic alteration adjacent to the invading sulphides, establishes that the lode was formed after the dykes were intruded, so that the high temperature features of the ore cannot be attributed to metamorphism and recrystallization, but are primary features of high temperature hydrothermal deposition.INTRODUCTIONTwo cross dykes are recorded on the plan of the 300-ft. level of the Broken Hill lode accompanying the report on the geology of the Broken Hill lode published by the Geological Sub-Committee of the former Scientific Society of Broken Hill (1910). One dyke occurs in Block 12, and the other in Block 13, and both were stated to consist of a dark basic amphibole rock, called diorite for convenience. The more southerly dyke was traced from some distance out in the footwall, and even through the lode, by means of occasionalpatches of it still existing in the ore, in a direction...

Jan 1, 1956

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 B Brattli

The dispersion pattern of heavy metals in soil and water is a consequence of complex geophysical and geochemical processes. Metal release from mining sites and subsequent migration occur primarily through acid mine drainage and erosion of waste and tailings dumps. Water plays a significant role in heavy metal mobilisation. Whilst it acts as a storage buffer for the pollutants, it is also the medium in which most of the reactions take place, and is undoubtedly the most significant transport vector in the pollution process. The intrinsic properties of the acidic drainage such as chemical composition, speciation of key mineral components, redox potential and pH are master variables controlling metal release, transport, deposition, reactivity and availability to biota. The mobility of heavy metals is strongly increased by acidification from acid mine drainage, and the discharge of these metals into the receiving waters results in numerous physical, chemical and biological responses in which the environment can affect the metal and vice versa. The result is an overwhelming number of association/dissociation, substitution, adsorption/desorption reactions, giving rise to a complex migration pattern. The attempt to understand and describe the dispersion pattern of heavy metals is complicated by the nature and level of interaction between the geochemical and hydrodynamic processes that generate and control the movement of the pollutants in the geosphere. Transport models which can be used to predict the behaviour of metal pollutants in a natural environment are still in the initial phases of development and their application to real life situations is limited. The Biochemical Cycle adds another dimension to the mobility of heavy metals. Metals form an important component of the food chain for man and plants. Biological uptake of metals from the bedrock and soil by organisms can result in migration paths very difficult to follow. Biodegradation or assimilation is just a tip of the iceberg.

Jan 1, 2003

By E A. Agorhom, M Beyuo, C Owusu, I Quaicoe

Understanding the mineralogy and liberation of gold particles in an ore is key to the development and optimisation of gold processing operations, being cyanidation or gravity separation. This can be achieved through basic historic geological information, gold deportment studies, chemical speciation and metallurgical test works. The present study assessed the nature of the occurrence of gold particles (mineralogical composition, liberation, associations and surface chemistry) and its effect on the process route (cyanidation and gravity separation) of a typical paleo placer gold ore deposit within the Tarkwaian Rock system. The investigative approach used involved chemical assay, quantitative X-ray diffraction (QXRD) and quantitative evaluation of minerals using scanning electron microscopy (QEMSCAN). The ore samples (A, B, C, D, E, F) used were obtained from six active pits of a gold mine working on this orebody. The results of the mineralogical analysis revealed that the ore is highly oxidised and comprised quartz (>80 per cent) and Muscovite mica (>6 per cent) as the major mineral phases in all the samples. Trace amounts of hematite, kaolinite and todorokite were also identified in all the samples. The chemical analysis showed presence of gold (Au) in all the samples with samples B (3.62 g/t) and C (3.96 g/t) containing the highest concentrations. Trace amounts of copper (Cu), iron (Fe), sulfur (S), aluminium (Al), arsenic (As) were also detected in all the ores. The QEMSCAN mineralogical liberation and gold association results revealed that the gold grains were relatively coarser in all samples (P80 > 80 µm Au in size) except F (P80 < 32 µm Au in size). Gold grains were highly liberated especially in sample B with the majority of the locked gold grains forming complex associations. All the samples responded well to cyanidation and gravity separation except samples C and F, respectively.

Aug 24, 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 Sijing Cai, Chengpu Zhou

The requirement of mineral resources is increasing as the economy is continually increasing in China. The mining practices of various complex sulphide deposits and precious metal deposits, and the treatment of mine tailings and other industrial solid wastes, have greatly improved fill quality in the metal mines. From early-1980s, high density slurry fill, paste fill of total tailings, low density slurry fill with addition of silicate gelling agent, etc has been studied and applied, and some progress has been achieved. Today, mine tailings, slag and power plant ash are widely used as fill materials in mining. A number of cemented fill mines equipped with large capacity trackless mining machines are in production. Recently, The 3rd Chinese National Symposium on Mining with Backfill, 1995 has been held, the progress of fill technology in mines has been exchanged and summarised. In the paper, some aspects of fill technology used in the metal mines of China are briefly introduced and some applications of fill research work are presented.

Jan 1, 1998

By Moelle KHR

The successful operation of a longwall face depends significantly on the efficient actions by support systems and on the ability to form a supported beam for a limited time span.The mechanical action of the supports can set up complex stresses in the immediate roofstrata.The cyclic application of supporting loads to the immediate roofstrata of a longwall face creates a special type of fabric disintegration in the rocks -affected. The mode of application and the distribution of the supporting forces is thus severely modified in a number of cases.The occurrence of true fatigue damage in brittle sandstones has been identified by studying the subcritical crack growth and microcrack development in the fracture-tip region. Several mechanical effects peculiar to the cyclic fatigue process have been identified. These effects had not previously been widely recognized. Damage in brittle rocks subjected to cyclic loads is shown to be distinctly different from any other damage processes under either monotonic or sustained (creep) loading conditions. The face support systems will frequently support rockmasses with mechanical properties not identified in conventional monotonic or sustained load tests.

Jan 1, 1991

On-line radioisotope gauges determine information on the characteristics of ore to enable improved control of processing operations. In the metalliferous mineral industry, in-stream analysis systems based on radioisotope X-ray techniques determine concentrations of valuable minerals at various stages of the concentration process. In the coal industry, on-line gauges determine ash and moisture contents, and the specific energy of coal.In-stream analysis systems developed in Australia are installed in about 30 mineral concentrators. Their use has led to the increased recovery of valuable minerals, and the time taken to recover the cost of installation is usually several months. The savings to Australia resulting from use of these analysis systems is estimated to be more than $A 15 million per year.Australian experience in the training of mineral industry personnel shows that the most effective approach is to combine courses on nuclear techniques and control of processing operations. This is the basis of Australia&apos;s contribution to the minerals sub-project of the United Nations Development Program (UNDP) Industrial Project.

Jan 1, 1985

By S K. Michelic, N Preisser

For certain applications, steels have to feature a very distinct and well-defined level of cleanness in terms of the number and composition of non-metallic inclusions. Therefore, one crucial aspect of steelmaking is removing and controlling said non-metallic inclusions during the process. Particle removal during ladle refining comprises three stages, namely: 1. Flotation 2. Transport through the steel/slag interface 3. Dissolution of the particle in the slag. Only if all three stages are completed the particle can be considered as fully removed from the steel melt which, in turn, leads to the slag being one of the most influential parameters for inclusion removal and control. Depending on the composition of the particles and the slag, the dissolution can be controlled by different mechanisms. This study focuses on the diffusion-controlled dissolution of solid oxidic particles in slags. For this, a model of particle dissolution has been developed. For modelling diffusion, either the differential equation following Fick’s second law can be solved, or an analytical solution to this equation valid for stationary interfaces can be used. Both approaches allow for calculations of concentration profiles of the dissolving species in surrounding slag. From this, the mass flux can be derived, which finally leads to calculating the boundary layer velocity due to considerations of mass balance. In this work, both methods as well as results of dissolution experiments using High Temperature Confocal Scanning Laser Microscopy are compared. This research aims to provide a framework for diffusion-based dissolution modelling in further expanding the understanding of particle dissolution in secondary metallurgy.

Aug 21, 2024

The relationship between comminution testwork results and the milling circuit that is subsequently selected is not a direct one and frequently involves recourse to databases of past test results. This in itself reflects the lack of a systematic engineering approach in the design process. This paper reviews comminution tests for SAG mill design in an attempt to identify where the essential information comes from that will be used in mill selection. The conclusion is that results from traditional test methods, including obscure and little used procedures like the Mokken test, are more valuable from an engineering perspective than parameters for breakage rate based modelling. Suggestions are made on ways in which existing test procedures can be enhanced in order to generate parameters that can be directly related to characteristics of the milling circuit being designed.

Jan 1, 2002

By R H. Sillitoe

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Geological concepts are employed routinely in porphyry copper exploration at the area selection, prospect appraisal and deposit definition stages. Regional, district-scale, deposit-scale and laboratory-based concepts can all play a role, with the resulting porphyry copper models providing templates for the integration of geochemical and geophysical responses and interpretations. Of the 19 concepts and parameters selected for brief discussion, those relating to subdivision of porphyry intrusions, understanding of diverse and commonly complex alteration-mineralisation patterns and lithocap characterisation are undoubtedly the most influential in exploration. Several of them are of particular importance because of their role in promoting grade development. Additional belt-, district- and deposit-scale features are currently little used but hold promise, whereas others have less practical value but help in underpinning the evolving porphyry copper genetic model.CITATION:Sillitoe, R H, 2015. Recent advances in porphyry copper geology and their exploration utility , in Proceedings PACRIM 2015 Congress, pp 35–44 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By M H. Mian

Much has been published on resuspension of sediments in lakes and estuaries. In general, resuspension has implications on transport and release of contaminants from the sediments. It has been shown that wind-induced waves contribute to erosion of sediments, which are then distributed to various sections of the water body by currents. Empirical equations formulated on the basis of cohesionless sediment behaviour have been applied to the design of a few tailings ponds in different parts of the world, especially in the selection of the necessary depth of water to minimise negative environmental impacts. The paper highlights the shortcomings inherent in these equations using field-measured data from a tailings site in Canada. Laboratory measured tailings properties are used to identify critical shear stresses required to initiate tailings erosion. The influence of cohesion on resuspension of fine-textured tailings is discussed.

Jan 1, 2003

By Peck W

The tunnel alignments investigated for the Gosford Regional Sewerage Scheme are located in the Terrigal Formation and are covered for most of their length by a thick blanket of soil and weathered rock. The following techniques were found to be most effective in geotechnical investigations for tunnelling in this area: air-photo interpretation, seismic surveys to pinpoint drilling targets, in-situ measurements of strength,deformation modulus and permeability in cored holes, and the construction of rock- mass models. Cross-hole seismic modulus measurements, surface resistivity soundings and electric well-logging techniques were found to have limited applicability due to adverse local conditions.

Jan 1, 1976

By Broome A

In a technologically oriented industry, it is important to understand and apply technology very consciously to create competitive advantage. Technology is not an activity which is simply restricted to CSIRO or the research and technology department. Technology improvement is a part of everyone&apos;s role. It is a way of life - the technology facet of continuous improvement. For this reason, The AusIMM has organised this Travelling Technology Forum - a series of presentations about automation in mining. To make the message more accessible, The AusIMM had originally planned to take the Forum to four regional mining centres: Mackay/Townsville, Singleton, Burnie and Kalgoorlie, but only one seminar was held, ie at Singleton in March 1997. Seminars at other locations were cancelled because of insufficient registrants. The presentation by Andrew Logan of BHP Cannington was not available for the Singleton forum. The aims of the forum were: ò to heighten awareness of the key technologies and their impact in the minerals industry in the medium term; ò to foster creative thinking; ò to encourage people to broaden their technical and commercial skills and develop individual networks and linkages based on an interest in these key technologies; ò to share information on the application of these technologies in the industry; ò to promote an enhanced appreciation of the need for an innovative culture; and ò to encourage staff to consider post graduate courses in technology management. The AusIMM wanted to not only raise awareness about `automation in mining&apos; issues, but also to get technology in a more general sense back onto `centre stage&apos;. The Forum was generously supported by CSIRO, Western Mining Corporation Ltd, BHP Coal Ltd, Aberfoyle Limited, Goldfields Ltd, Novacoal Australia Pty Ltd, Pasminco Ltd, and RGC Limited. The program was endorsed by the Centre for Mining Technology and Equipment (CMTE). Copies of the full papers are available from the authors, see `References&apos;.

Jan 1, 1997

In November 1992, the Internal Revenue Commission (IRC) was formed from the rperggr of the Papua New Guinea Taxation Of- fice (PNGTO) and the Bureau of Customs, and now has the re- sponsibility for the administration of direct and indirect taxes on a national basis in Papua New Guinea (PNG). Since that date we have undertaken many initiatives to make the new organisation more efficient and responsive to clients&apos; needs. Income Tax The mining industry is catered for, in respect of income tax, un- der a separate taxation regime within the Income Tax Act (ITA), Division 10, as well as some general provisions within that Act as may be applicable. Division 10 is itself broken up into subdi- visions to cover the different types of mining leases, namely Spe- cial Mining Leases (SMLs) and Mining Leases (MLs), and peri- ods of time during which those sub-divisions apply. Ring Fencing Income tax assessed on the mining industry, with the exception of Mining Leases (these will be explained later), has a project basis of assessment, that is, each project is assessed separately as if the taxable income of the taxpayer from operations attributable to the project was the only assessable income derived by that taxpayer. This is often referred to as "ring fencing". This is an important point to consider because losses from unsuccessful projects cannot be set off against income from those that are suc- cessful, except in very limited specific circumstances, such as where an unsuccessful exploration licence is cancelled or surren- dered. The project basis of assessment applies to both resident and non-resident companies. A relaxation in the &apos;ring fence&apos; provisions was applied from 1st January 1995, where ten percent of exploration expenditure, in- curred in areas outside of Special Mining Leases and Petroleum Development Licences in a particular year of income, can be claimed as an outright deduction which is limited to ten percent of the tax otherwise payable in that year. This was introduced to encourage exploration in PNG.

Jan 1, 1997

By Garg R. K

Himalayan ranges on the northern border of India are source of many perennial rivers and suitable sites for large dams have been located therein. However, Himalayas are young mountains and comprise of comparatively weaker rocks having adverse geological features like shear seams, thrust zones, minor and major faults and intense jointing. Tehri dam project under construction, is located in lower Himalayas. It envisages construction of a 260.5 m high earth and rock fill dam and an underground power station of 2000 MW (Eight machines of 250 MW each, four of which will be reversible) installed capacity. This dam will be the highest and the underground complex will be the largest to be constructed in India in the Himalayas. The under- ground complex comprises of 25 km of tunnels varying in diameter from 6 m to 11 m and seven large cavities of various sizes, the biggest being 22 m in width, 194 m in length and 65 m in height. Rock formation in the power house complex belong to phyllites having various joint sets spaced from 0.5 m to 3 m. Due to the poor geological conditions and closely spaced net work of large cavities, the planning, analysis and design of the cavities is a challenging job. Many aspects have to be considered in determining the sizes, locations and orientations of the various cavities taking into account the properties and jointing pattern of rock mass, functional requirements and economics. Correct evaluation of loads and forces is necessary for economical design of supporting system for the various cavities. Rock loads on the roof of cavities and their supporting system will be assessed with the help of the latest methods. The stability of the rock mass around the cavity will be evaluated by elasto- plastic method using finite or boundary element techniques. A scheme of field investigations, laboratory tests and instrumentation for deter- mining rock properties in preconstruction stage and for monitoring behaviour of the underground cavities during and after construction is envisaged.

Jan 1, 1987

By Wymer DG

The concept of hydro power in deep mines is based on the exploitation of the hydrostatic head that can be gained as refrigerated cooling water descends in shaft pipe columns from the surface, to provide hydraulic power for machines at the working face. This paper describes the work done on two important aspects of the controlled distribu-tion of the high pressure water within a mine, namely the control of pressure under normal operating conditions, and the control of flow in an emergency situation following a pipe breakage. Suitable methods of control have been determined using theoretical techniques to model the steady and unsteady flow behaviour of the water in the pipeline, and taking into consideration the environmental constraints on the types of control devices that can be used. The preferred approach is one in which the high pressure water itself is used as the control medium. The control valves themselves can be fairly conventional in design, but in the case of pipe break protection it is shown that a less conventional approach based on the use of a hydraulic fuse gives improved control performance.

Jan 1, 1985

In common with general experience in the iron-making industry overseas, Australia has in recent years suffered a deterioration in the physical quality of her iron ores in their suitability as a direct blast furnace feed. The increasing amounts of fines and the more friable nature of lump ore, especially in the ore from the Cockatoo Island deposits in Yampi Sound, Western Australia, have focused attention on problems of ore preparation and agglomeration, particularly sintering.Although very small pilot scale Dwight-Lloyd type sinter machines were operated at the steel-making centres at Newcastle and Port Kembla during World War II, no sizeable capacity was installed, so that ore was charged to the blast furnaces almost entirely unscreened, and the resultant flue dust was stockpiled.Towards the close of the war, the pilot plant at Newcastle was replaced by a small machine, adjacent to the flue dust stockpile, with a rated capacity of some 20 tons per hour. After approximately five months of part-time operation, this plant was closed down in January, 1945. Production was not resumed until December, 1950, when, due to a temporary ore shortage, it was decided to supplement available ore with sinter produced from the large flue dust stocks of about 300,000 tons. In spite of mechanical and process difficulties, inherent to the design of the plant, operation was continued on a two-shift basis, with several shutdowns for extensive overhaul and plant alterations, until September, 1954, when production was put on a three-shift basis. Addition of Yampi ore fines to the sinter machine burden was not commenced...

Jan 1, 1957

By Gyasi-Agyei Y

In recent years rapid advances have been made in the technology used for hydrology and erosion modelling of rural catchments. These advances have been driven by the growing availability of digital terrain maps that can be used to automatically define catchment properties that previously had to be manually extracted from contour maps. In addition, these models have, in principle at least, more powerful predictive capability. The author is involved in a number of projects to migrate and further develop these models for application to mine rehabilitation assessment. Current technologies for hydrology and erosion assessment (eg CREAMS, ANSWERS) are reviewed, underlying principles highlighted and deficiencies in the context of mine rehabilitation design assessment addressed. The advantages and disadvantages of the new digital terrain map tools (eg WEPP, SIBERIA) are discussed. Current work integrating these new models with existing rehabilitation design tools (eg ACIRL&apos;s ARGUS computer package) highlights the advantages of an integrated approach using digital terrain maps; cheaper, faster, lower impact and more flexible rehabilitation design. The use of novel visualisation tools to aid the design process is discussed. The paper is illustrated by applications to mine sites in Queensland and the Northern Territory.

Jan 1, 1995

By Mills J. C

Concentration ranges are presented for 15 trace elements not previously reported in Australian bituminous coals. The results were obtained by instrumental neutron activation analysis, which has sufficiently high sensitivity to enable determination of many elements directly in coal at concentrations less than a few &#181;g/g. The ranges found in Australian coal are similar to the ranges reported in North American bituminous coals.

Jan 1, 1983