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By P S. Datta, V N. Misra

Higher bed height up to 680 mm, including 30 mm hearth layer of sized return sinter and high suction below the grate bars up to 1400 mm WG have resulted in increasing the productivity to a level of 33 t/m2/day and reduced coke rate to a level of 46 kg/tonne sinter. The ferro-wastes like blue dust, flue dust, mill scale, collection from dust catcher and gas cleaning plant, etc have been successfully added in charge mix to produce quality sinters. In this paper, brief description of the work done at Regional Research Laboratory (CSIR) in last few years and two case studies are discussed including the successful development of pan sintering units.

Jan 1, 2002

By A C. Edwards

The Mongol-Okhotsk belt consists of detached fragments of the Circum Pacific fold belt which have been trapped within the Mongol-Okhotsk fold belt. In its western part, the structures of the belt form an east-facing loop that is not connected with the other orogenic structures of Central Asia. In the eastern part of the belt (the Mongol-Okhotsk suture zone) the terranes form a zone between the Siberian craton to the north and the Bureya composite terrane to the south, that is linked with the Circum Pacific belt. The accretionary terranes, together with their Precambrian backstops, form a series of consistently-stacked, paired units that are bounded by northwest and north trending sinistral strike-slip faults. The ages of the rocks forming these accretionary complexes vary from Late Precambrian - Carboniferous in the west to Cambrian - Jurassic in the east. The terranes developed due to a progressive westward stacking of the accretionary complexes during the process of accretionary growth. The magmatic rocks young eastward indicating that migration of the magmatic front of the arc followed the eastward growth of the accretionary complexes. The accretionary terranes may be differentiated by their Paleozoic lithological assemblages. Only the Selemdzha, Niman, and Kerbi terranes located in the eastern part of the Mongol-Okhotsk suture zone contain significant amounts of black shale, and it is these terranes that host the bulk of the hardrock and placer gold mineralisation that is present within the suture zone. Gold mineralisation is present both as vein style and disseminated mineralisation within structural duplexes.

Jan 1, 1999

By V Poizat

In different parts of the world the term epithermal is commonly used for a variety of deposit styles. Using the redox state of the ore-forming fluid (inferred from mineralogy and alteration), the metal assemblage of deposits, and other characteristics, at least five different styles of epithermal deposit can be distinguished. Most of these different deposit styles appear to be related to magmatic fluids, with differences resulting from different compositions of source magmas. The most common style of epithermal deposit (low-sulfidation gold-silver deposits associated with calc-alkaline volcanic rocks) remains the most difficult to explain; the metals in these deposits may be derived by basement leaching without magmatic input, or they may come from magmatic volatiles, with contaminated I-type or S-type magmas as the most likely source.

Jan 1, 1995

The interaction of flotation collectors with sulfide minerals takes place at the solid - solution interface. The electrochemistry of the processes which affect this interface are discussed. The interaction of xanthates with sulfides is an electrochemical process, xanthates being electro-oxidised to chemisorbed xanthate and dixanthogen. The role of oxygen is to provide a cathodic process to allow the anodic oxidation to occur. The hydrophobic condition of the mineral surface is brought about by the presence of the oxidised xanthate species. The action of reagents which can activate or depress the flotation of sulfides is discussed briefly.

Jan 1, 1971

By H A. Challenor

Eyewash safety showers located in remote hot environments may be unsafe to use due to excess water temperature and high risk levels of water borne bacteria such as Legionella. Australian Standard AS 4775 specifies that dispensed water shall be bacteria free and have a maximum temperature of 37.8°C. Legionnaires disease is contracted when water aerosols containing Legionella bacteria are inhaled.Laboratory tests show 30 to 70 times more aerosols are generated by showers operating at 38°C than with showers operating at 25°C. Furthermore, excess temperature in flushing water can cause burn injuries leading to hospitalisation, skin grafts and/or permanent scarring. Excess temperature also increases the rate of reaction to corrosive substances, opens pores in the skin to allow greater dermal penetration and can cause dizziness and fainting by dilating blood vessels and reducing blood pressure.CITATION:Challenor, H A, 2017. Managing excess temperature and high risk levels of Legionella bacteria in eyewash safety showers, in Proceedings Iron Ore 2017, pp 337–346 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

The application of biogeochemical methods in mineral exploration in semi-arid to arid environments in Western Australia has been investigated in an area near Norseman.The study involved a comparison of trace element characteristics of rock, soil and plants in the vicinity of the Pioneer BB prospect, where nickel-iron sulphide mineralization occurs in a "greenstone" sequence of ultrabasic, basic and sedimentary rocks.Analyses of unweathered and partly weathered rock from diamond drill cores show the ultrabasic rock to be highly variable with respect to Ni, Cu, Co, Zn and Mn.Samples of weathered bedrock and overlying soil were analysed for total trace element contents and for the trace elements associated with secondary iron and manganese oxides. Approximately 30 per cent of the total nickel content of the weathered basic rock is associated with secondary iron and manganese oxides, compared with approximately 15 per cent in the weathered ultrabasic rock.The soil has a sufficient residual content to provide a reliable indication of the chemistry of the underlying rock. Total trace element analyses of the -89 mesh fraction show strong anomalies for nickel and copper over the mineralized zone. Important amounts of nickel, cobalt and, to a lesser extent, copper are apparently associated with secondary iron and manganese oxides in the soil.Melaleuca sheathiana (tea tree) has been used to study the relationship between soil and plant chemistry. No strong relationship between plant and rock type was observed. Analyses were made of leaves, twigs, wood, bark and roots, and all plant organs were found to have anomalous nickel and copper contents near the mineralized zone. Leaves were found to give the best contrast in the anomalous area and to show fewer erratic values than other organs. It is concluded that the uptake of trace elements by tea tree is low in the semi-arid to arid environment of Western Australia, but that analyses of the plants do reflect the presence of mineralization.

Jan 1, 1973

By J M. Galvin, B J. McKinnon

Lightning Ridge, Australia, is the largest opal producing area in the world. Most opal is mined from shallow underground mines by individuals or small partnerships with the industry having been protected from large-scale development to date. The safety performance of opal mining has lagged both general mining industry standards and community expectations. The application of geotechnical analysis to the opal fields has the potential to considerably reduce injuries and fatalities. With consideration of the local culture, preliminary geotechnical analysis has been applied to some current methods of work utilised at Lightning Ridge. Practical solutions have been advocated and are presented in this paper. Improvements to safety generated by these practical solutions indicate that further geotechnical research at Lightning Ridge is warranted and would be beneficial.

Jan 1, 2002

By M Humphreys

Multi-episodic mineralisation is often characterised by different spatial trends exhibited by different generations of the mineralisation. The structural complexity of mineralisation together with the heterogeneous nature of the mineralised zones prevents unambiguous application of the conventional deterministic methodology for 3D constraining of the mineralised domains (ie conventional wireframing is ambiguous).A different approach, discussed in the present paper, includes a probabilistic definition of the domains encompassing one statistical population of the data. The domains are defined geostatistically using the indicator probability model. An indicator threshold is chosen for the definition of the high and low-grade domains. The spatial distribution of this indicator is then modelled by a variogram. The probability of exceeding the given grade threshold is than estimated by ordinary kriging for each modelled block. Blocks are then grouped according to their probability of exceeding the threshold and a continuous closed volume (domain) created from this likely patchy grouping using an appropriate structural model to fill the gaps). Methodology for the geostatistically assisted domaining is discussed in the paper. It is suggested that this technique represents an additional tool facilitating a structural interpretation of the mineralised zones.After the geostatistical domaining of the lode has been completed the grade within each of the domains is modelled using Uniform Conditioning method. Application of Uniform Conditioning for modeling the grade distribution has a significant advantage over linear methods (such as inverse distance or kriging) because Uniform conditioning enables estimation of local recoverable resources at different selective mining unit sizes that can be substantially smaller than the drilling density and are unable to be estimated directly.

Jan 1, 2002

Mine ore, reduced to minus 71/2 in. by primary crushers, is stockpiled. Size reduction of the reclaimed material by secondary and tertiary crushers is achieved in a closed circuit crushing and screening plant. Screen products of minus 30 mm plus 6 mm lump, and minus 6 mm fines are stockpiled by conveyor and stacker systems prior to rail despatch 10 port facilities at Dampier. Crusher settings, determined from experience, are closely maintained to obtain the desired lump/fines ratio. Chemical and sizing analyses from automatically taken samples are used to maintain product specifications. The beneficiation plant upgrades the fines product when this is necessary. The recorded wear life of individual plant components is the basis of a planned maintenance programme.

Jan 1, 1970

Constraints on the mineral industry are best treated as issues that have to be understood and managed in partnership rather than in conflict with communities. TheZapopan development at Mt Todd in Australia and the Martha Hill development at Waihi in New Zealand are but two of many recent successful examples at the local level.   However, at the national level, the issues are more complex and more difficult to resolve because the most influential stakeholders are now the urban electorates and governments defer to their perceptions when making decisions and policy. In the developed countries, government policies for the development of mineral resources have been progressively eroded since the early 1970s. At the same time policies for the environment and for native land rights have generally been carried out in a way that has reduced access to minerals and increased the cost and risks for prospectors and developers (Hancock, 1995). Since the end of the Cold War, the lesser developed countries (LDCs) have introduced policies to attract investment in their mineral resources that remained undeveloped under previous unstable or hostile regimes. The increased attraction of these LDCs and the decreased attraction of the developed countries has caused many Australian and North American companies to outlay increasing proportions of their budgets and capital investment in the LDCs.   Significantly, LDC policies for environment protection do not discourage exploration and mine development, Surveys of the relative appeal of the LDCs and the traditional mining countries of the developed world, rate Chile, Argentina and Indonesia ahead of Australia and Canada in terms of risk, delays and ease of doing business (Australian Mining Monthly, February 1994).

Jan 1, 1995

Exploring the Breakage Environment in Mills with Discrete Element Methods

Sep 13, 2010

Human-caused global warming has become the environmental cause celebre of the early 21st century. The strong warming alarmist camp currently includes the United Nations, most Western governments, most of the free press, many large corporations (including Enron, before it failed), the major churches, most scientific organisations and a large portion of general public opinion. This phalanx of support notwithstanding there is no scientific consensus as to the danger of human-induced climate change. There is, therefore, a strong conflict between the level of public alarm and its scientific justification. How can this be? In a democracy, the media serve to convey to the public the facts and hypotheses of climate change as provided by individual scientists, governmental and international research agencies, and NGO and other lobby groups. In general, the media have promulgated an alarmist cause for climate change; they have certainly failed to convey the degree of uncertainty that is characteristic of climate science, or a balanced summary of the many essential facts that are relevant to human causation. Climate change is as much a geological as it is a meteorological issue. Natural climate changes, both warmings and coolings, are indeed a societal hazard. We usually deal with geological hazards by providing civil defence authorities and the public with accurate, evidence-based, general information about events like earthquakes, volcanic eruptions, tsunamis and floods, and then by adapting to the effects when a damaging event occurs. As for other major natural disasters, the appropriate preparation for extreme climate events is to mitigate and manage the negative effects when they occur, and especially so for dangerous coolings. Attempting instead to æstop climate changeÆ by reducing human carbon dioxide emissions is a costly exercise of utter futility. Rational climate policies must be based on adaptation to dangerous change as and when it occurs, and irrespective of its sign or causation. The issue now is no longer climate change as such, the reality of which will always be with us. Rather, the issues are, first, the failure of the free press to inform the public about the true facts of human-caused climate change and of the dangers posed by natural climate change. And, second, the vested interests held by many of the groups of warming alarmists. These interests include not only the obvious commercial ones, but also the many scientists and science managers who have discounted or remained silent about the huge uncertainties of the human-caused global warming hypothesis because it suited them to do so. Public opinion will soon demand an explanation as to why experienced editors and hardened investigative journalists, worldwide, have melted before the blowtorch of self-induced guilt, political correctness and special interest expediency that marks the sophisms of global warming alarmists.

Jan 1, 2007

Since the end of World War n, many important developments have taken place in the investigation of the phenomenon of brittle fracture in mild steel. Fractures in certain classes of welded ships, in welded bridges, penstocks, etc., focussed a great deal of attention on the interrelationships of design factors, service conditions, and steel quality on the generation of catastrophic failures.Much publicity has been given these major failures, and there is perhaps a tendency to forget that mild steel, under certain conditions, as well known to behave in a brittle fashion in a wide range of everyday engineering applications.For instance, many who are connected with the haulage and lifting of heavy loads will be familiar with the bright "crystalline" fractures of crane hooks and chains which sometimes follow sudden jarring; those concerned with the heavy pressing and shaping of steel plate will not be unaware that at times sudden brittle splits or tears will develop for no obvious reason in, say, rolled pipes or in dishings.In fact it will be evident upon reflection that in many cases the conditions which mild steel has to withstand during processing into an engineering part or structure are more severe than those it wili be called upon to endure during service. In this sense brittle fractu;res in mild steel are much more frequent than are commonly supposed.Two modes of fracture are now generally recognised to occur in metals, namely, shear and cleavage. The latter manifests itself by the so-called "crystalline" fracture (here...

Jan 1, 1954

By J Temos

This paper outlines a number of immediate practical approaches to continuous improvement in environmental management in the minerals industry. It puts these into context with longer time-frame step-change approaches whose gestation may take a decade. Examples of improvements and approaches are drawn from WMC operations.

Jan 1, 2002

ABSTRACTRock stresses can be modified by physicochemical processes.If rock pores allow the ingress of water and oxygen, but are not large enough to permit the exit of larger molecules of weathering products, anomalous rock pressures develop. Rock masses may also be subjected to osmotic pressures developed as water diffuses into pores and joints filled with saline water. Anomalous rock pressures may also develop as gels filling pores undergo syneresis and as salts crystallize from pore solutions.

Jan 1, 1968

The Ekati Diamond Mine is located on permafrost terrain in CanadaÆs Northwest Territories. The mine rock consists of: diamond-bearing and barren kimberlite; and surrounding waste rock such as granite. The kimberlite occurs in several vertical æpipesÆ that are, or will be, mined using open pits. Early predictions of drainage chemistry at Ekati identified the potential for ARD due to sulfide oxidation from both waste rock and kimberlite. This was surprising for the kimberlite, because neutralisation potentials (NP) are typically hundreds of kg CaCO3 equivalent/t. However, subsequent testwork showed that substantial portions of the NP ædisappearedÆ quickly, apparently due to the unusual non-carbonate mineralogy. In any case, additional predictive work concluded much of the rock was benign and there would be no ARD. Shortly after mining started, ARD appeared from both the waste rock and kimberlite, although a few years passed before the company and its consultants recognised that at least some of the acidic water was ARD. Numerous other processes have been put forward as possible explanations for the remaining acidic drainage, although none have been either confirmed or eliminated. Because: the causes of the ARD and acidity are not known; no causes have been eliminated and more have been added; drainage chemistry was not predicted accurately; and future mining will encounter similar rock. I believe the Ekati Diamond Mine needs high-level assistance to understand current chemistry and to avoid problems with future drainage. Organisations like INAP, MEND3, and universities could provide this assistance.

Jan 1, 2003

By T P. Fischer, S N. Williams, N C. Sturchio

Chemical and isotopic analyses of fumarole gases from Galeras Volcano, Colombia provide significant insights into the origin of volatile components in the magma. Water comprises a mixture of magmatic (rock-equilibrated at high temperature) and meteoric, with the relative proportions varying through time. Carbon isotopes are most consistent with a mantle source, although other contributions to the system cannot be ruled out. Nitrogen most likely originated from organic matter in subducted oceanic sediments. All of these 'primary' components have been modified somewhat by interaction or exchange with other reservoirs during ascent to the surface. In addition to information on the origin of the gases, these data show significant temporal variations precursory to eruptive events. Chemical ratios change and water becomes more meteoric in character prior to eruptions.

Jan 1, 1995

Development of Grindability Tests Based on Direct Measurement of Energy Nowadays, for the characterisation of the grindability different grindability indices - Bond-work index (Wi), Hardgrove Grindability Index (HGI) or Zeisel specific grindability (Wt) - are used. Generally, the grindability tests are carried out under relatively simplified circumstances, in a special dry batch mill with defined feed size material until prescribed conditions are reached at room temperature. However, in the fine- and ultra fine grinding, which is a frequent task (fly ash, tailings, alumina, etc), a fine material (<50 - 200 ¦m) is usually ground down to the few micrometers. The conventional grindability testing methods and apparatuses (Bond-, Hardgrove-, Zeisel-processes) for their determination, although, are not suitable directly to measure the grindability of such fine materials, since the maximal particle size of the feed material (0.5 - 3 mm) to be tested is much higher. One of the important goals of the research carried out in our Institute was to develop the novel grindability testing methods, which are suitable for the fine and ultra fine grinding, and additionally provide the possibility for the fast determination of the grindability. In order to realise the above aim the conventional Bond- and Hardgrove- mills were modified in order to directly measure the grinding work. In particular, the Hardgrove-mill was equipped with a simple torque-meter (load cell). The Bond-mill was rigged with a digital electric power measurer. The systematic experiments were carried out parallel in both mills using the conventional and the developed methods. Finally the results of both were compared. The measuring results have proved that the Bond-work index can be determined based on the developed methods. The new grindability testing methods were applied successfully in several industrial research tasks for the determination of the specific grinding energy and the Bond-work index. These methods can be also used in the industrial practice for the control of the grinding process.

Sep 13, 2010

By J Merrells

Fluor, together with our clients, has yielded significant reductions in the total cost of mining projects by employing a systematic and methodical process of cost reduction. This paper outlines this structured approach to reducing the total cost of projects through the gathering of information, the evaluation of the zero base design, and the development of the execution strategy for the project in the study phase.Over the recent iron ore boom the cost of growth projects escalated rapidly due to a variety of factors including the engineering cost of re-designing facilities, construction in remote areas and an increase in the ‘perceived’ capital requirements for maintainable and operable facilities.Fluor has made strategic steps towards safely reducing the capital intensity of projects, by working with clients to develop zero base designs which utilise the minimum technical requirements in order to meet the function of the plant and then add cost for safety, maintenance and operability only where clearly justified.This paper has set forth a structured three phased approach to focus the team on reducing capital cost while maintaining a low increase in engineering effort.The initial ‘gather’ phase focuses the team on acquiring information and identifying decisions that will need to be made so that the team can prioritise and focus the attention on areas that will provide the greatest benefit. Within this phase the identification of zero base design requirements, review of lessons learnt and analysis of capital cost levers, allows the team to identify the key decisions on the project that will affect the capital cost.In the subsequent ‘evaluation’ phase the team established the zero base design, using the hierarchy of cost reduction as a guide to focusing the team’s attention on high yielding cost saving opportunities.In the final phase the team develops the execution strategy which will yield the least cost using strategies and tools such as modularisation, standardisation, replication, strategic sourcing and 3D design.CITATION:Merrells, J, 2017. Reducing total project cost in the study phase using zero base design, in Proceedings Iron Ore 2017, pp 621–626 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

This paper reviews recent positive developments in Europe on the regulation of gold mining. However, it also examines the problem that while gold projects may be bankable and technically and environmental defensible, the odds tend to be stacked against granting of an environmental permit. The historic background to this situation is examined and current developments and initiatives are critically analysed. Standards and benchmarks for the industry have been established across the community and these have a strong influence in European Union accession (and aspiring) states as well. While this is welcome in regard to improving environmental performance, it also represents a significant milestone with mining (and particularly gold mining) now æon the mapÆ as a legitimate enterprise, a situation that was patently not the case prior to 2003. At the project level, very frequently, the difficult biophysical problems are addressed and satisfactorily dealt with according to the new regulations, but still there are problems regards trust and acceptance that underpin a æsocial licenceÆ. What goes wrong and how can companies deal with the social/environmental issues that lead to entrenched views and concerns, irrespective of any amount of demonstration of good practice and corporate social responsibility? What is the role of the non-governmental organisation (NGO) and are they as accountable and responsible as they should be? The findings presented draw upon recent experience with the environmental permitting of projects in Spain, Greece, Romania, Bulgaria and Serbia on behalf of Australian, Canadian and British companies as well as international funding institutions.

Jan 1, 2007