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The dissolution of the naturally occurring mineral zircon (ZrSiO4) is examined after ball milling it with magnesium oxide for up to 100 hours in a laboratory mill. There was little effect on the solubility for the initial two hours where size reduction of the zircon was considered to be the dominant effect. Beyond two hours the dissolution increased as a function of the square root of milling time. X-ray diffraction of the powders did not reveal the identity of the soluble phase. However, a nanocrystalline phase was present after milling and this is thought to be the soluble phase.

Jan 1, 2000

By R L. Brathwaite, S E. Belliss

Linear and semi-circular features were mapped in the volcanic terrain of the southernCoromandel Peninsula, North Island, using JERS-1 synthetic aperture radar (SAR), Landsat-4 Thematic Mapper, and SPOT-2 multispectral satellite data, digital elevation models, and aeromagnetic data. The mapped features typically correspond to recognised physiographic features and are thus a useful aid to mapping the structural trends in the region. Major linear features exhibit a strong N-S to NNE-SSW alignment, and lesser NW-SE and NE-SW trends. All these are superimposed on pervasive, closely spaced, NNE-SSW and NNW-SSE lineaments present over most of the hilly parts of the map area. There are few major E-W aligned features. Some alignment trends correspond to strike directions of veins in the epithermal gold-silver deposits of the region, but none of the known mineralised structures were visible on the remote sensing data.   The volcanic rocks are Late Cenozoic in age and include a variety of rock types: andesite and dacite flows, domes and tuff breccias, rhyolite domes, tuffs and tephra, lacustrine siltstones, and ignimbrites. Mapping of different textures in the SAR image failed to provide additional information on rock types to that derived from the Landsat and SPOT images. A simple discrimination of rock units based on radar texture is apparently prevented by the complex volcanic geology, superimposed hydrothermal alteration, and long period of erosion.

Jan 1, 1994

By Wyborn L. A I, Idnurm M, Hinman M. C

Comparison of the Proterozoic Apparent Polar Wander Path (APWP) for Australia with the corresponding geology of northern Australia suggests that a number of discrete interplate tectonic events, manifested on the APWP as bends or inflections, may have controlled sedimentary basin evolution, ore fluid production and the timing of mineralisation. Similar features in the Phanerozoic APWP for the North American plate appear to correlate with major orogenic events, basin deformation, movement and 'entrapment' of hydrocarbons and minerals. Interplate tectonic events cause intraplate deformation which in turn controls the subsidence/uplift and sedimentation histories of the basins. Interplate events are thus responsible for creating, deforming and destroying sedimentary basins and the associated petroleum and mineral systems. The basins of northern Australia show remarkable similarities in the successions of volcanic and sedimentary deposits. Unconforrnities of regional or sometimes only local extent have been mapped between the major sedimentary sequences and it is predicted that interplate tectonic events corresponding to bends or inflections on the APWP directly reflect the processes that have produced these widespread unconformities. These processes are also likely to have controlled the geometry and character of the fluid migration pathways and hence the mineralising events. Palaeomagnetic studies of Proterozoic rocks in sedimentary basins provide a tool for predicting the timing of regional mineralisation events, particularly for low-temperature mineral systems. The techniques, when coupled with systematic regional basin analysis, using petroleum exploration techniques, may identify a number of new mineral 'plays' in northern Australia. Prominent inflections in the APWP occur at approximately 1700, 1670, 1650, 1600, 1540, and 1480 Ma. Each of these may be related to a regional compressional deformation, important mineralising event, or significant change in style and type of sedimentation. Most appear to be associated with magnetic overprints. Some of the inflections between 1400 and 540 Ma may also mark significant events in the evolution of Meso- and Neoproterozoic basins. Further work is required to correlate inflections in the APWP with alteration events in order to understand their regional significance.

Jan 1, 1994

By K Bojarska

Examination of wastes aimed at evaluation of their usefulness for utilisation needs applying modern chemical testing methods. The XRD-XRF-ICP-GC/MS set of test methods constitutes an integrated testing system enabling ecochemical examination of wastes. As far as the problem of time-consuming operations is concerned, the offered system fits in a market-oriented field of activity of accredited chemical laboratories. Within a reasonable period of time, it allows to obtain information about mineralogical and chemical properties of wastes. It provides full range of information beginning from mineral composition (XRD) through chemical composition including the number of elements and organic compounds (XRF-ICP-GC/MS) up to the contents relating to the amounts of ingredients, both organic and inorganic in the leaching tests (ICP-GC/MS). The XRD-XRF-ICP-GC/MS testing system proves to be of particular importance in obtaining reliable results enabling to perform precise assessment (from ecochemical point of view) of wastes to evaluate their usefulness for utilisation in building materials, in civil engineering and reclamation works.

Jan 1, 2003

By Phillips D. N, Herbert H. K, Fletcher A. C, Lewis R. K

Quartzite is a common feedstock used for the production of silicon by reduction at high temperatures in a submerged electric arc furnace. Silica fume, formed as a by-product in this process, contains crystalline silica in the respirable fraction. The crystalline silica in the fume represents entrained quartz derived from unreacted quartzite raw material within the furnace. A knowledge of the fragmentation of quartzite feedstock, in response to thermal disaggregation in the furnace, is important in feedstock selection to help minimise (a) the amount of crystalline silica in fume, critical from an occupational health and safety perspective, and (b) impurity levels necessary to achieve the highest possible purity of product silicon. In this study, a series of quartzites has been assessed in terms of the above requirements and correlations drawn between mineralogical and chemical characteristics. Alkaline solubility correlates with grain-size and level of stored strain in the quartz matrix. Grain-size affects the surface area available for attack while stored strain enhances the chemical reactivity of the strained matrix as well as profoundly influencing the disaggregation and microfracturing characteristics of strained grains and, hence, available surface area for chemical reaction.

Jan 1, 1995

By B M. Guerin

In this paper, some of the constraints to applying bioremediation to the decontamination of polluted soils are introduced. Particularly, attention has been given to those associated with the geology of the polluted site. Areas which require further research have been addressed and indicate that geologists will play a key role, alongside microbial ecologists and engineers, in designing and implementing bioremediation strategies.

Jan 1, 1992

By D A. Manhire, R M. Flores

The commercial develop of coalbed methane from the Powder River Basin has demonstrated that low-rank coals can be a viable source of gas. Currently over 20 000 coalbed methane wells exist in the Powder River and it is predicted that there will be 50 000 wells by 2010. What makes the Powder River Basin successful is the thickness of the coal (in excess of 30m) as well as the low ash content (

Jan 1, 2002

Mining is a high risk industry where miners seek to secure certainty in all of their dealings. The introduction of native title to the Australian legal system with the High CourtÆs 1992 Mabo decision and subsequent Native Title Act 1993 has added to the risks associated with implementation and the ongoing operation of exploration and mining projects. The High CourtÆs Ward case in August 2002 confirmed Crown ownership of minerals and petroleum. But the Court also found that a mining lease that allowed an exclusive possession for mining purposes did not extinguish all native title rights and interests. Although the Court was specifically considering WA mining tenements, the WA mining lease is very similar to the mining leases and licences that exist across Australia, meaning that these tenements are unlikely to fully extinguish native title. The Ward case means that native title remains squarely on the table now and into the future for those involved in developing exploration and mining projects. However, certainty and workability is capable of being secured and this paper discusses some means by which this may be achieved. The paper starts by considering two of the many 1998 amendments to the æfuture actsÆ regime under the Native Title Act, Indigenous Land Use Agreements (ILUAs) and the application of ægood faithÆ negotiation to all negotiating parties. It then looks at native title agreements, other issues affecting negotiations and tips for negotiation technique.

Jan 1, 2003

Interest in the sampling of refined copper cathodes has heightened over the last ten years. This has followed the increasing importance of cathodes as the principle trading form for metallic copper. It has also been given impetus by recent trends for quality certification of manufacturing inputs, specifically the AS3900 and IS09000 series of standards.

Jan 1, 1976

By Vynne J. F

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

Jan 1, 1995

FOR many years past it has been the practice at the Bairnsdale School of Mines to treat any parcels of auriferous concentrates sent in from the surrounding district by roasting them in a handworked reverberatory, and then chlorinating or cyaniding the product. According to Donald CIark, who has done a large amount of work on these ores, the results obtained were fairly satisfactory extractions of over 90 per cent being claimed. With some modifications, the method has been very generally adopted, not only in Gippsland but throughout Victoria. It is, however, difficult to get exact information as to the extractions actually obtained, and unfortunately no records of working results have been kept at the Bairnsdale School of Mines.Having treated several lots of ore by this method during 1907 and 1908 with unsatisfactory results, the writers thought it desirable to make a detailed investigation on some particular ore, both in the laboratory and on a working scale. The ore selectedwas a parcel of low-grade concentrates from Stirling, a small mining field situated about forty miles to the east of Bairnsdale. This ore was chosen chiefly on account of the heavy and inexplicable volatilization loss which took place even on roasting with the greatest care; the loss amounting to between 10 and 15 per cent. In the experiments here related, three main objects were kept in view:-1. To determine with what mineral 01' minerals the gold and silver were associated...

Jan 1, 1909

The control objectives and constraints for grinding circuits are ana- lysed, taking a single-stage ballmill-cyclone circuit as an example. The design of a hierarchical modular control system is described, for implemen- tation on modern microprocessor-based control systems. Product sizing measurement is identified as a problem area, and a new approach to product sizing inference, from on-line cyclone feed and overflow measure- ments, is presented. The procedure over-comes several practical difficulties of a previously proposed inferential method and is therefore expected to find application in more advanced grinding circuit control systems.

Jan 1, 1988

In many metal mines in China,the 70B2 series of fans has been used for main fans for a long time.These fans generate higher static pressures than are required for the relatively high equivalent orifices of the ventilation systems of many of the mines. As a consequence, their running efficiency is common only around 30%. The loss of power is significant.

Jan 1, 1988

The mining industry has a well deserved reputation earned over the years for innovation, engineering, management and the quick application to mining of emerging technology. The cumulative result is the economic exploitation of lower grade resources. The developments during the last decade have done nothing to tarnish the reputation. There are many that come easily to mind: the use of contractors for both surface and underground operations, a trend toward mine management contracts, the increasing recognition of the economic potential of ground support, and the development of physical measures to achieve it, - sophisticated measures to analyse blasting , and thus improve fragmentation, - instrumentation to assist geotechnical appraisal, - the development and application of the powerful and flexible, excavator, - the evolution of measures to improve grade control, - massive improvements in equipment productivity and reliability built largely around the application of hydraulics, - the development of powerful computer packages for orebody modelling, mine design and extraction, - simple "dense" fill systems, - maintenance management techniques including the greater use of off-site maintenance of exchange components, - the utilisation of communication systems for data transfer.

Jan 1, 1989

Now that Japan has achieved a remarkable high growth and joined the ranks of economic powers, she is required to take a stance proper to her new position toward international co- operation among Western advanced countries, economic/technical aids to Southeast Asian and Pacific LDCs, and others. As a field subject to such international cooperation programs, the development/use of coal resources has been winning increasing attention in recent years. Coal is positioned as one of promising alternative energies. With Southeast Asia plus Japan and the EEC serving as the two nucleus polar regions, total coal demand in the free world is projected to jump 37% in the year 2000 from the present level and steaming coal imports in the world, primarily destined for power generation, almost double the 1983 level. Such being the situations, Japan's tech- nologies related to coal resource development, if successfully introduced into coal-producing countries to help them boost their production, can directly lead to international cooperation that Japan is now required to fulfill. At home, however, the Japanese coal industry has been just on the wane due to various press- ing problems, such as wider differentials between overseas and domestic coal and deeper/ remorter mining. The industry was named atop in a list of the industries requiring restruct- uring at a meeting of the Economic Structure Study Committee held prior to the decision- making of the 8th coal policy, which slashed coal production planned for the last fiscal year of its life to some 10 million tons, a drop of as much as 50% from nominal output planned in the 7th policy. Under such circumstances at home and abroad, a pioneer study has been under way since fiscal 1984 as part of Japan's energy cooperation in the Pacific. The study is based on the Pacific coal flow concept hammered out by the Agency of Natural Resources and Energy of the MITI.

Jan 1, 1987

By K H. Esbensen

Sampling of grain, animal feeds (solid and liquid) including important mineral mixtures in the Danish agricultural sector is subject to an ongoing investigation with the objective of improving existing (suboptimal) sampling procedures. Results from the first six months are presented here; the project will continue for two more years and will include international collaborators (Australia and Canada). The Danish authorities have instituted a system of control analysis, which contains a set of mandated sampling and analysis methods. From a preliminary survey it was concluded that in fact all of the existing sampling procedures are not optimised in the light of Pierre GyÆs Theory of Sampling (TOS).

Jan 1, 2005

The present stage of economic development of the Broken Hill lode, attained after 40 years of active exploitation, leaves little opportunity for the study of the zone of secondary sulphides.Little remains of the oxidised zone, and the observations of the secondary sulphides of copper and silver can rarely be made on specimens collected in situ. A few specimens containing secondary...

Jan 1, 1927

By Denholm W. T, Rankin W. J

The reduction of zinc from lead blast furnace slags using hydrogen was studied at 1300¦C as part of a laboratory investigation of zinc fuming. To perform the experiments, 300 g "spent slag" was melted in a crucible. Hydrogen was then injected into the slag through a lance and fresh blast furnace slag was added regularly in small quantities over a period of 40 minutes. Zinc added in the fresh slag was reduced and the zinc level of the bulk slag attained a steady state value of between 1 and 9% after about 10 minutes, depending on the gas injection rate. Because of the high reactivity of hydrogen, bulk supply of hydrogen to the slag was the rate limiting step at the flow rates used and it is believed that the gas-slag reactions in the system were at equilibrium. A partially/stabilized zirconia cell with a Ni/NiO reference electrode was immersed in the slags during the experiments and the steady/state oxygen potentials of the slags were measured. By using the experimental oxygen potential values and calculated values of the steady state concentrations of zinc in the offgas, the activity of ZnO in the slags was calculated from the Gibbs's free energy change for the reaction:

Jan 1, 1989

The sulphide ores of the Kalgoorlie goldfield have long been looked upon as' refractory, involving special metallurgical treatment. For many years two kinds of treatment have been practised-(l) wet treatment, including fine grinding, amalgamation or concentration of the free gold, concentration of the sulphide minerals with subsequent roasting and cyanidation, and cyanidation or bromo-cyanidation of the residue from the concentrating operation; (2) dry-crushing of the ore and roasting the whole of thecrushed ore, amalgamation of the gold in the calcine during fine grading, followed by cyanidation. The wet treatment was advanced a stage further when, in 1929, the Lake View and Star Ltd. adopted large scale flotation. As a consequence, however, further metallurgical problems were introduced. This paper covers the investigation, ,of one of the most prominent of these problems.Flotation preceded by strakes was satisfactory to a point.The flotation concentrate consisted largely of auriferous pyrite and tellurides, and the gangue minerals in the concentrate were practically barren.Several sources of loss of gold values were, however, found to be associated with this circuit, viz.-(a) There was the loss of gold in the flotation tailing.(b) Loss by dusting during roasting of the flotation concentrate.(c) Loss of gold in the cyanided residue.

Jan 1, 1937

By Hamilton TM

The Holocene Minninup shoreline is a coastal barrier system stretching from Bunbury to Busselton, in southwestern Australia. It has developed in a microtidal swell wave environment, under the influence of the post- glacial marine transgression and Holocene sea level variation. Barrier sediments thin rapidly across a shallow shelf, and consist of quartzo-felds- pathic sands with a minor skeletal carbonate component. Holocene shelf deposits are laterally extensive sheets overlying Pleisto- cene limestone. Modern carbonate production is small. Development of the Minninup barrier system has been controlled largely by low rates of sediment input from terrigenous and carbonate sources, late Holocene sea level fluctuati,.,s, and pre-existent coastal landforms composed of Pleistocene limestone. Modern controls on sedimentation are the refracted, shoaling swell wave regime, and onshore winds, which combine to promote nett northward longshore drift. Holocene barrier systems of the southern Swan Coastal Plain are of several different types. These include prograded sequences of beach ridges overlying shoreface sediments, such as is found at Rockingham and parts of Geographe Bay, and complex polygenetic systems typified by the Leschenault Peninsula. Pre- liminary investigations of the barrier stratigraphy of the Minninup shoreline indicate that both progradational and polygenetic sequences are present. The processes involved in shoreline development and heavy mineral accumulation are being studied using aerial photograph inter- pretation, beach profile monitoring, sampling, and granulometric analysis. This will lead to an enhanced understanding of the mechanisms of heavy mineral accumulation, and assist in the development of genetic models as aids for Exploration.

Jan 1, 1986