Search Documents

The Hemersley Ranges are located in the North West Division of Western Australia and extend, approximately, from latitudes 21¦ 30! to 23¦S and longitudes 117¦ to 120¦E. Their mean height above sea level is'. 2,000 feet, and they rise from 600 to 800 feet. above the gen- eral level of the tableland which extends south-east from the coastal town of Roebourne.. Mt. Bruce, the highest peak, is 4,024 feet above sea level. The ranges are intersected by numerous north-flowing streams, dry during the greater part of the year, which have carved deep gorges, and it is in these that the principal deposits of orocidolite outcrop. The presence -of the mineral was first recorded in 1917., but the deposits remained untouched until 1937 when reports of a strong market demand for-croeido lice resulted in considerable prospecting and mining activity, particularly in Yampire, Wittenoom and Daleis Gorges. . It was established also that the blue asbestos belt extended from Willi- Wolli Springs north-west to Millstream Station, i.e.,-over a.:length of 180 miles and a width of 20 to 30 miles. A number of attempts were made to develop aid treat the Yampire and Wittenoom'Gorge deposits from 1938 onwards, but, for a ,variety of reasons, none of these-proved successful. Current production,. is wholly by Australian Blue Asbestos Pty. Limited at Wittenoom Gorge. This company commenced operations at the Wittenoom Mine in 1946, with an output of 601.8 long tons of- fibre,. and later transferred tb the Colonial Mine about one mile to the north-west. Output has been increased steadily to an' average of 12,000 to 14.,000.. long tons; per annum over the past six years. The total Western Australian output to the end of 1962 is reported by the Mines Department as 110,013 long tons valued at úAl2,403,728..

Jan 1, 1964

By M Alston

Organisations’ incident classification processes are plagued by the overclassification of events, often leading to excessive workloads and suboptimal outcomes. This presentation addresses the pressing need to rethink how incidents are classified to maximise organisational learning and minimise systemic risk. A major issue in the current incident classification landscape is the tendency to classify events at high levels, overwhelming organisations with investigations they cannot efficiently handle. This results in inadequate risk reduction and learning opportunities. The link between injury classification and investigation methods further compounds these problems, creating unnecessary administrative clutter. Challenging the misconception that every event, no matter how minor, requires a comprehensive investigation, this presentation advocates for a shift in perspective. The key recommendation is to decouple injury classification and risk matrices from the decision-making process regarding what and how to investigate. Instead, the emphasis should be placed on identifying opportunities for organisational learning and risk reduction. Organisations can streamline their incident management processes by adopting a more pragmatic approach that aligns incident classification with the organisation’s investigation capacity. This transformation focuses on achieving meaningful outcomes, enhancing safety and improving performance. This presentation provides an innovative process for organisations to revamp their incident classification practices, enabling them to harness the full potential of incident data for learning and risk mitigation. It highlights the importance of aligning incident classification with the opportunity for organisational learning, ultimately leading to more effective incident management and enhanced safety outcomes.

Apr 16, 2024

By Little T. N, Bettess D

For many mining operations the challenge of equalling World Best Practices has become the key motivator for increasing mine productivities and for lowering total costs. In most instances this will only be achieved if mines optimise their total system rather than minimising specific costs within unit operations. In the past, drilling and blasting have been viewed as a cost to be minimised rather than operations which should have their impacts fully leveraged. Once a hardrock orebody is defined the activity which has the most substantial impact in determining the efficiency of a mining operation is the blasting. The output from a blast affects every downstream operation; only by understanding the extent and interactions can the mine be optimised. Substantial improvements to hardrock mining, quarrying and excavation operations are achievable. Instead of seeking the regular one to three per cent improvements based on reduction of consumables, mine operators would be well advised to go for much bigger targets of ten to 30 per cent by fully leveraging the drill and blast operations.

Jan 1, 1995

By W Stange

Assessing the risks in a mining project is a key aspect of project evaluation. This is an exacting and demanding task because of the complexity due to the need to deal with uncertainty over long time periods. The way risks are assessed and managed is critical to the long-term success of the projects and the business. Discounted cash flow (DCF) analysis is commonly used for project and risk evaluation. A discount rate is selected that accounts for uncertainties in the cash flows. However, it is difficult to determine an appropriate discount rate due to the large number of factors that need to be considered and the complex relationships between risk sources. Using a proven framework, ævalue at riskÆ (VaR), this paper proposes to rigorously model and quantify ærisk at sourceÆ. The approach was first employed to assess financial market risks and is now widely used in the banking sector for risk assessment. In project evaluation, all risk sources are identified and estimated separately to ensure the overall project risk is quantified accurately. A bottom-up approach has been proposed. Estimates are first carried out for risk factors at the bottom of the project structure. The assessment is then applied at increasingly higher levels until the overall project risk is estimated. Value at risk is a versatile methodology and can be used in a local or integrated manner. The final value is objective and the calculation steps can be easily justified and followed. Four case studies have been included to illustrate how the proposed approach can assist management in decision-making.

Jan 1, 2009

By M Zoorabadi

Overcoring is a common technique to measure in situ rock stress using the concept of stress relief. The strains measured during overcoring are used to calculate the stress tensor assuming continuous, homogeneous, isotropic and linear elastic behaviour. This approach does not recognise any effect of the thickness of the rock annulus produced during overcoring instead assuming that the stresses are entirely a function of the difference in strain between the start of the overcoring and the end with no regard to the transient strains produced. Three-dimensional numerical modelling was used to simulate the overcoring process and investigate the impact of core diameter on the transient stresses and strains during overcoring. This study showed that in thicker core, maximum transient axial stresses and strains occur when the drill bit approaches the measuring point and greater tensile axial stresses were produced when the annulus was thinner. CITATION:Zoorabadi, M, 2018. Numerical study of annulus thickness on overcoring stress measurements, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 274–278 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

A brief descri;tioki is given of nuclear power reactors and their fuels. These fuels are made from a variety of uranium compounds such as uranium dioxide, and uranium carbide as well as uranium metal and its alloys. The various processes used to produce some of these compounds from yellow cake are outlined. Using the natural uranium, heavy water reactor by way of illustration, fabrication of fuel elements is dis- cussed and the characteristics of U02 powder required for this partic- ular fabrication are indicated. The flowsheets and equipment presently in use overseas for production of this type of U02 powder are described. Possible areas where improvements might be made to this conventional process are enumerated and some details are then given of the programme of work which has commenced at the A.A.E.C. Research Establishment to gain experience in the general field of nuclear grade UO20

Jan 1, 1968

The South Comet mine is an underground silver-lead-zinc mine located on the West Coast of Tasmania with an annual production in the order of 35 000 tonne per year. All ore mined is shipped to the Rosebery mill by road, a distance of 17 km.

Jan 1, 1993

An image analysis system has been built which automatically digitizes camera input of rock fragments, analyses the digitised data to determine the sizes and shapes of the rock fragments, and outputs the analysed data to a printer in the form of a histogram or a scatter chart. The high speed of such a system allows for direct collection of data from material thrown into the air by blasting, material travelling on a conveyor belt, and material free-falling on to a stock-pile or into or out of a rock-crusher. Data on the blasted, un-crushed material provides information on changes in the lithology and structure of the rock face as it is quarried or mined: flatter fragments may represent approach to a brittle, unstable shear zone, or a change from sandstone to shale; so that the informa- tion reflects the effect on the sizes and shapes of the fragments by the blasting process and/or by the rock structure. The size and shape distributions of rock fragments produced during blasting and during processing may now be continuously monitored. Such detailed analysis of the results of fragmentation is labour-intensive and expensive when the size and shape distributions are obtained manually, but is cheap and efficient when using this image analysis system. Such a system will enable the results of blasting, quarrying, mining and crushing to be cheaply analysed and correlated with current and changing indus- trial practice so leading the way to increased productivity.

Jan 1, 1988

By S Smith

Several styles of copper (Cu) mineralisation are present at Sepon. Large tonnage, low grade skarn and carbonate replacement massive sulfide mineralisation occur within the metamorphic aureole of Permian-aged rhyodacite porphyry intrusions (RDPs). During exhumation and supergene weathering, this primary mineralisation has been upgraded to form high-grade chalcocite enriched zones up to 50 m thick, which comprises the bulk of Cu resources currently being mined at Sepon. Groundwaters remobilise Cu to form exotic accumulations of malachite that are locally hosted in irregular karsts in carbonate rocks, found up to 1000 m from source mineralisation. Khanong is the largest Cu deposit and recent discoveries have been made at Thengkham South, Thengkham North and Phabing. All deposits have formed by similar processes of mineralisation. However, all differ due to local variations in host rock lithology, structural setting, and hydrological conditions. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By S MacKinnon, J Kok

Potential areas for improvement in flotation performance were identified during JKTech model development surveys in October 2003. Subsequent implementation of the JKTech recommendations in consultation with flotation cell manufacturer Outokumpu have resulted in gold flotation recovery increases of more than four per cent over a two-year period. One of these recommendations was the installation of High Shear Stators in the Cleaner and Recleaner flotation cells. The High Shear Stator installation project was justified based on simulations completed using JKSimFloat. Bubble size measurements completed before and after installation of High Shear Stators showed a reduction in mean bubble size of approximately 50 per cent in the Cleaner cells. Both Cleaner and Recleaner banks showed a significant narrowing of the bubble size distributions following the installation. Plant gold recovery increase resulting from the installation of High Shear Stators was 1.1 per cent, with a 1.9 per cent increase in flotation gold recovery and 5.4 per cent increase in flotation sulfur recovery. Based on the 1.1 per cent recovery increase and total project cost of less than $200 000, the High Shear Stator Project NPV was $8 200 000 with a 0.25 year payback period.

Jan 1, 2006

The progress of longhole open stoping (LHOS) at The Zinc Corporation, Limited and New Broken Hill Consolidated Limited (ZC/NBHC) is described. The design of a novel sloped wall longhole stoping method at NBHC which should allow the cuplete extraction of the orebody without the formation of pillars and with minimal dilution of the ore with sandfill is reviewed.

Jan 1, 1983

By A M. Ebbels

"Underground mine scheduling decision-making has been based on production requirements, equipment productivities and the mine planner’s instincts on the best scheduling strategy for the mine to optimise the net present value (NPV) of a project.In the last few years, innovative software has been developed to optimise underground schedules based on NPV. The schedule optimisation tool (SOT) allows the user to set up scenarios based on grade, metal content, capital and operating costs.This paper discusses the results of two case studies undertaken using the SOT software to optimise the NPV of the projects.In each case study, the SOT software has been applied in two ways:using the original mine planner’s scenario and determining whether the NPV could be improved by changing resource capacitieschanging the scheduling goals to determine whether a different mining strategy would have a better NPV outcome.The outcomes of the case studies demonstrate that the mine layout and design were contributing factors to the overall improvement of the NPV and that SOT has a more noticeable impact on the NPV of projects where less sequence constraints are required, such as geotechnical sequencing and access development.CITATION:Ebbels, A M, 2016. Optimising underground mining strategies, in Proceedings Project Evaluation 2016, pp 60–65 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By M J. Davies, R S. Davies

Despite increased expenditure, the global discovery rate of world-class ore deposits has been in decline for over a decade (Schodde, 2017). Mineral exploration has traditionally followed an empirical approach, searching for evidence of mineralisation upon the surface of the planet, then drilling to define the extent of an ore body beneath the surface. As outcropping deposits in well-defined areas are depleted, there is a need for exploration to extend to less well-explored search spaces. One popular new frontier is exploration at greater depths beneath the Earth's surface. However, exploring for deep deposits with limited surficial evidence requires the implementation of predictive targeting methodologies (Hronsky, 2011; McCuaig & Hronsky, 2014). The Mineral Systems Concept (Hronsky & Groves, 2008; McCuaig et al., 2010) provides a framework for predictive exploration targeting. Ore deposit formation is recognised to be a focused mineralising event. These events represent self-organising critical systems and are underpinned by the interaction of complex, non-linear processes. Through the collection and analysis of datasets that map mineralising processes, it may be possible to predict the size and location of resultant ore bodies. CITATION: Davies, M J and Davies, R S, 2018. Beyond below-ground geological complexity: Developing adaptive expertise in exploration decision-making, in Proceedings Complex Orebodies Conference 2018, pp 95–98 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By D Giles

We present plate tectonic reconstructions, showing that porphyry-type ore deposits are spatially and temporally linked to ridge subduction. A reconstruction of the Peruvian subduction system reveals an immediate metallogenic response to the arrival of the Nazca Ridge at the subduction trench, followed by southward migration of the zone of metallogenic activity due to the lateral migration of the zone of ridge subduction. A similar pattern is recognised in central Chile , where the spatio-temporal distribution of giant ore deposits coincides with the arrival of the Juan Fernandez hotspot chain at the subduction zone. We conclude that there is a spatial and temporal link between ridge subduction and ore deposit formation, with high metal fluxes concentrated in zones of ridge subduction. Thus, the recognition of tectonic patterns associated with ridge subduction can provide insights into predictive mineral discovery by enhancing our ability to predict the position of large mineral deposits in other modern and ancient orogens. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

I would like to start by thanking The AusIMM and CSIRO for organising this excellent conference and inviting me to give a keynote address. Today I will focus on some broad observations of our industry, and leave the technical discussion to my colleagues who are presenting specific papers covering a wide range of topics. In preparation for this paper, I did a little research into the early history of the Pilbara iron ore industry. I was fascinated to read a quote attributed to Harry P Woodward, the Government Geologist in the late 19th century, before Federation. Mr Woodward described the Pilbara as an iron ore country and observed that æthere is enough to supply the whole world should the present sources be worked outÆ. Mr WoodwardÆs prediction could be viewed as wishful thinking and certainly at Hamersley Iron I would gladly envisage the Pilbara supplying the worldÆs entire iron ore needs! In reality, Western Australia accounted for 162 million tonnes or 36 per cent of seaborne trade in 2001. An impressive effort, but not quite the total world supply as Mr Woodward imagined. But we shouldnÆt dismiss these historical musings out of hand û perhaps we could see it as a challenge for the industry to æwork outÆ the present sources. We all know there is abundant iron ore in the Pilbara, and I expect it is only a matter of time until our collective technical expertise and sheer hard work will enable us to utilise its greater range of ore types. Opening up new markets will be a key pathway to creating additional value from the Pilbara ores. Today I will examine the state of play of our industry and the major influences that shape our business at present, before considering what the future might hold for us. I canÆt guarantee the accuracy of my crystal ball, but the stability and long-term nature of our industry does enable some reasonable hypotheses on where we are heading. I will also spend some time examining the way in which the iron ore producers are working to maximise the value of their resource base and obtain more from their existing capital assets.

Jan 1, 2002

The subject of steel wire ropes covers such a wide range of points that it would be impossible to deal with it fully in one paper, and in view of the apparent scarcity of published information on the subject it is proposed in this paper to deal with those items which should give the mining engineer a better understanding of the basic factors which affect the design.selection, and use of ropes. The matter will be considered under the following headings:-1. Brief history of steel wire rope-making.2. Rope-making terms.3. Wire rope materials.4. Characteristics affecting economy, operating life, and serviceability of a rope.5. Properties of construction of rope, and stresses met with in wire ropes.6. Drum and sheave sizes and sheave bearing pressures.7. Storage, handling, and maintenance of ropes in service.8. Common factors affecting rope life, particularly winding and haulage ropes.9. Inspection of ropes.GENERALWire rope, which was invented for, and first applied to mine winding, has become an indispensable aUXiliary throughout the whole field of mining, be it for underground, open cut, or dredge work, as well as the requirements of transport and treatment of ores.Though wire ropes appear simple collections of wire and fibre, the demands made upon them are many, and the stresses and abuses to which they are exposed in service are varying, and often of serious dimensions.The exposition of these stresses and abuses, particularly dynamic stressing, corrosion, etc., all of which seriously affect the safety and economical life of the ropes, is often enough to frighten most practising mine staffs, who are aware that before the requirements of economic operation stands the still more important question of safety in mining.

Jan 1, 1947

By Harrison J

The correct selection of equipment to use in a mine is a problem which constantly faces the mining engineer. In some cases a wide choice of equipment with different operating characteristics is available. If this equipment is to be used to assist in moving the ore it may be possible to build a computer simulation model to predict how it will perform. Typical problems that lend themselves to this type of analysis are presented. The computer models are constructed using a recent form of the GPSS computer language, namely GPSS/PC for the personal computer. This language allows the programmer to construct models in a very short time and at a low cost. Of great importance is the easy way in which it is possible to change the models to answer any of the "what if?" questions the engineer may pose.

Jan 1, 1987

By R Hindstr÷m

The demand for iron ore has increased dramatically in the last years and is forecast to remain on a stable high production level for years to come. ItÆs expected that the world economy is facing a stable continuous growth of iron ore to two billion tonnes and more over the next decades (Beddows, 2007). Furthermore it is expected that the existing and known high-grade ore resources will decline, and the iron ore industry will be forced to implement more and more advanced beneficiation plants. As a consequence of the more complex beneficiation requirements, there will be a need for modern solutions for iron ore dewatering that are reliable mechanically as well as cost effective and with high capacity per unit at the same time. Conventional vacuum filtration methods have been the most prevalent in fine iron ore dewatering. Product quality needs, lower ore grades, complex mineralogy and energy costs have resulted in iron ore producers seeking better solutions for dewatering, in particular pelletising feed. New advanced filtration methods have been introduced to the market. This paper describes how these modern methods are answering the needs of the industry. Performance of advanced dewatering technologies (pressure filtration and ceramic capillary action filtration) for iron ore applications has been studied, and the findings are based on both industrial and pilot scale experiences on different materials. For example, the results show that the cake moisture content of iron ore pelletising feed can be optimised more effectively by using modern filtration technologies. By selecting the most suitable and adjustable equipment, the effects of variations of feed material on downstream processes can be minimised and the possibilities of processing more difficult raw materials to high-quality pellets are better. The Larox Corporation develops, designs and manufactures industrial filters and is a leading technology company in its field. Larox is a full service solution provider in filtration for separating solids from liquids. As such, this paper compares the new developments in this market area with the prevailing known vacuum filtration technology, but focuses on a comparison between capillary action filters and rotary vacuum disc filters (RVDF). The trade name CeramecG is used to differentiate the Larox filter from the generic term.

Jan 1, 2007

The paper gives details of the reasons why attention was directed towards the modification of flotation cells. The cell volume and impeller speeds were reduced, and it is estimated that the power consumption for lead and zinc flotation will be reduced by about 2·8 kWh per ton of ore treated, and that substantial savings will be made in maintenance costs. The metallurgical efficien.cy of the operation has been maintained and attention is now being directed towards the improvement of grades of concentrates and recoveries of metals.INTRODUCTIONIt was on 1st August, 1934, that the first Denver No. 21 flotation cells were operated in the treatment plant of The Zinc Corporation Limited, in a pilot Nant which had been installed to determine the economics of all-flotation as against the then existing gravity and flotation practice.The ore being mined at that time came from the lead lode which consists of a granular mixture of galena, marmatite, chalcopyrite, tetrahedrite, pyrrhotite, pyrite and lollingite with a gangue association of calcite, quartz, bustamite, rhodonite, manganhedenbergite, garnet, fluorite, manganocalcite and apatite. The silver content of the ore occurs in three minerals-tetrahedrite, dyscrasite and pyrargyrite, the last two mentioned occurring in microscopic association only.A parallel lode, known as the zinc lode, was well developed at that time. The common lead lode gangue minerals-calcite, rhodonite, bustamite-were rare in the underground exposures of the zinc lode. No metallurgical work was done on this ore during the pilot plant operations although since then both lead and zinc lode ore have been treated.Early in 1936 plans were made for the complete re-organization of the mine operations, and in view of the metal-

Jan 1, 1956

By I Onederra

A better understanding of the detonation performance of an explosive charge can be gained by directly measuring pressure, temperature and velocity of detonation (VOD). This is particularly important with explosives used in the mining industry because their performance is directly influenced by the degree of confinement given by the borehole diameter and the surrounding rock mass. A project funded by the Australian Coal Association Research Program (ACARP) was initiated in early 2009 with the view to design and build cost-effective prototype instrumentation to measure the relative differences in detonation pressures and temperatures of commercial mining explosives. The project’s primary focus was on low-density explosives. Low-density (also referred to as low shock) explosives have been available in various forms for nearly 20 years. There have been significant advances in the availability, reliability and flexibility of these explosives, which now offer a range of densities and degrees of water resistance. Their detonation performance is not well understood and cannot be accurately predicted with current ideal and non-ideal detonation codes. It was therefore viewed as important to be able to directly measure pressure and temperature during the detonation process of these complex mixtures in production blastholes. Identifying the pressure release patterns of both conventional and low-density explosives under different geotechnical conditions should provide the necessary information to both validate detonation codes and better define input parameters for breakage and fragmentation models. This paper gives a general description of the prototype instrumentation developed and reports on the results obtained to date in full-scale conditions.

Nov 8, 2011