Search Documents

By Zichenko ZA, Volkov SV, Shaluhina LM, Emelyanov AF

A method of selective gold recovery from black sands has been elaborated which is based on the liquid phase low temperature chlorination of materials. A liquid agent mixture of sulphur monochloride S2C12 and sulphur dichloride SC12 is used. This method ensures the gold extraction either in the state of AuC13.SC14 complex salt solution or as metal. The kinetics and main physico-chemical parameters of the process (eg density, solid: liquid ratio, temperature) have been investigated. The materials investigated were quartz-insipid ride samples with low sulphur and high iron (up to 70 per cent Fe2O3) contents. Gold recovery is 96 - 99 per cent at temperatures not exceeding 100¦C. Most of the associated minerals remain in the cake. To obtain metallic gold, the resulting solution of the AuC13.SC14 salt after leaching is reduced by hydrazine with subsequent annealing. The elaborated method is remarkable for small energy expenditures owing to low process temperature and a high gold dissolution rate. The solution of sulphur chlorides and other reagents are used in closed cycle.

Jan 1, 1993

Pike River Coal Limited is in the process of developing the Pike River Coal Mine in the Paparoa Ranges of New ZealandÆs South Island. The mine will be developed to extract a coking coal deposit of the Brunner Seam, some 46 km north-east of Greymouth, using a combination of continuous miners and hydraulic extraction. The mining area is located within Department of Conservation (DOC) land and is adjacent to the escarpment of the Paparoa Range and the Paparoa National Park.   As such, the major restriction to planned extraction is protection of: +        the western escarpment, +        vertical and sub-vertical rock faces, +        permanent water courses, +        significant vegetation, and +        steep slopes.   The mine will use its elevation advantage to hydraulically flume coal from the working faces to the pit bottom area where it will be slurried to approximately 35 per cent density of solids and pumps down a slurry line to the coal prep plant some 10.5 km down the Pike River Valley. The coal will be sold on the export market as a high quality coking coal for international steel making.

Jan 1, 2006

By Ormsby W. R, Nicholson P. M

Woodcutters is a polymetallic vein-style deposit hosted by sediments of the Palacoproterozoic Whites Formation which forms part of the sedimentary sequence in the central Pine Creek Geosyncline. Past production and identified resources total over eight million tonnes at 5.5 per cent lead, 12.1 per cent zinc and 110 gA silver. The local geology is influenced by Archaean basement highs; the Rum Jungle and Waterhouse Complexes. Unconformably overlying basement are interbedded clastic and crystalline carbonate units (Batchelor Group) representing cyclic changes in the depositional environment. These exhibit onlapping features with the underlying rocks. Sediments of the overlying Frances Creek Group suggest a quiet period during subsidence and subsequent increase in water depth (the carbonaceous dolomitic shales and the interbedded dololutites of the Whites Formation) followed by proximal uplift resulting in the inundation of turbiditic flows (Acacia Gap Quartzite). All of the Palaeoproterozoic rocks show evidence of being affected by penecontemporaneous, basement circling faults with steep dips. The stress regime during the deposition of the Frances Creek Group was characterised by alternating episodes of thrusting and transpression. Periods of relaxation also occurred. The compression resulted in major NS strike-slip (transpressional) faulting, en-echelon NNE trending folds and NW-SE tensional cross faults. Thrusting produced N-S striking, steep dipping reverse faults and a possible decollement immediately above the Batchelor Group. Relaxation is evidenced by the intrusion of lamprophyre dykes and dolerite sills (Zamu Dolerite). Mineralisation at Woodcutters occurred in faults within the Whites Formation, probably synchronous with deformation and the deposition of the upper parts of the Frances Creek Group. Greenschist facies metamorphism occurred as the rocks were further buried. Several massive sulphide bodies occur at Woodcutters. A number of features influence the location and shape of these bodies. They are: ò the N-S transpressional faults and in particular associated dilation zones; ò intersection of the N-S transpressional faults with the axial plane of the NNE trending Woodcutters Anticline; ò intersection of the N-S transpressional faults with the NW-SE cross-faults; ò intersection of dololutite rich units with the NS transpressional faults where local replacement takes place; ò thickening of the lithological units in the vicinity of the anticlinal axis; and ò the anticline doubly plunging to both the north and south. The mineralisation exhibits vein-like features as well as epigenetic textures. Its boundaries are sharp, its thickness varies rapidly down dip and along strike, and no alteration halo exists though stringer veins of quartz-carbonate-pyrite ¦ sphalerite/galena occur in close proximity. A number of sulphide mineral assemblages have been recognised, each separated by periods of deformation and partially replacing the earlier assemblages. Vertically continuous zonation patterns highlight the presence of rich galena-sphalerite-silver in zones of maximum dilation and pyrite-arsenopyrite-gold concentrated at the along strike peripheries. The genetic model proposed has the mineralisation occurring whilst the transpressional regime was active. It was deposited from the same fluid that elsewhere in the Geosyncline formed the stratiform deposits higher in the sedimentary pile. Hydrocarbons sourced from the organic-rich Whites

Jan 1, 1994

By H Zhang, M Karimi, M Hassan, S Saydam, B Li

With the prevalence of Mine Internet of Things (MIoT), different types of sensors have been widely deployed in mine sites for environmental monitoring and operational management. Currently, sensors in mine sites are mainly powered by cables or batteries. However, the deployment and maintenance of a power supply network can be difficult and expensive, and batteries have a limited lifespan. The vibration energy harvesting (VEH) technology can be used to provide power for lowpower sensors in mine sites. This presentation briefly introduces three widely used VEH methods (ie piezoelectric, electromagnetic, and electrostatic). The performance of a commercial electromagnetic energy harvester (ReVibe model D) is evaluated based on the vibration of a lab vibrator (3 g, 50 Hz) and an idling SUV automobile (0.3 g, 25 Hz). Experimental results indicate that a ReVibe energy harvester can generate adequate electricity to power a sensor, and its power output depends on the load resistance as well as the vibration frequency and amplitude of vibration sources. To apply VEH to mining applications, this study also analyses the characteristics of vibration sources at the mine site based on the vibration data collected from various operating machines in a coal handling and preparation plant (CHPP). The vibration analysis results indicate that all the measured vibration sources in the CHPP can generate stable and abundant vibrations, characterised by substantial amplitudes (up to 5.55 g) and low dominant frequencies (ranging from 14 Hz to 25 Hz), which are sufficient for VEH.

Sep 1, 2024

By N Bezuidenhout

The performances of ten field-scale experimental final covers were evaluated over an eight-year period. The covers were evaluated as part of the rehabilitation of acid generating coarse coal reject dumps and opencast coalmines in the Northern KwaZulu Natal province in South Africa. The main purpose of the experimental covers was to restrict rainfall infiltration into acid generating coal discard. The mean average rainfall over the monitoring period was 839 mm with 84 per cent occurring between October and April. The average evaporation was 2100 mm. The site is described as a ædry siteÆ since the evaporation exceeds rainfall by a significant margin. Approximately 30 per cent of rainfall infiltrated the uncovered cells. Rainfall infiltration into the fine coal discard was reduced to 20 per cent and 15 per cent for a 300 mm and 500 mm cover respectively. Infiltration was reduced to ten and 12 per cent of rainfall for fine coal discard provided with a 1000 mm double soil cover and a compacted bottom layer. This relatively high infiltration was probably caused by moisture being entrapped in the bottom retentive layer, and not being released by evapotranspiration. The best performing cover comprised 1000 mm single soil with a compacted bottom layer and infiltration was reduced to four per cent of rainfall. Rainfall infiltration into sloped cells varied between seven per cent and 14 per cent of rainfall. The computer software, SoilCover, was used to predict infiltration and moisture content in the cover. Predictions of rainfall infiltration were accurate, but were less accurate for covers where the hydraulic properties of field compacted soils were not adequately characterised. Oxygen ingress was significantly reduced for cells provided with a 1000 mm cover. Oxygen concentrations were generally below one per cent, with the exception during exceptionally dry periods when the cover dried out, resulting in increased oxygen ingress. For other covers, and the uncovered cells, oxygen concentrations were close to atmospheric concentrations. During the eight-year monitoring period, acid breakthrough occurred in five of the cells, including three uncovered cells, one cell with a 300 mm cover and one sloped cell. In contrast, cells covered with 1000 mm, bottom compacted soils shows a marked improvement of leachate quality, indicating that sulfide oxidation processes have been slowed. There was a distinct relationship between oxygen ingress and leachate quality for all of the cells. No cover degradation was evident over the eight-year period, except for some erosion observed on a sloped cell. The results indicate that the onset of acid drainage can be delayed by perhaps hundreds of years and salinity loads can be reduced by more than 90 per cent, if coarse coal reject dumps in the KwaZulu-Natal provinces in South Africa are provided by an adequate cover system. These research outcomes can be extrapolated and applied to other dry site regions where similar materials are being considered.

Jan 1, 2003

A research and testing facility has been developed at Simtars to allow the spontaneous combustion testing of coal on a large scale. In this adiabatic reactor, the coal particle sizing is closer to that which could be found in the goaf and therefore the reaction is more likely to simulate the underground situation. This allows aspects of the spontaneous combustion process and methods for detecting a heating to be investigated which cannot be done in an operational mine. Up to 18 tonnes of run of mine or crushed coal is loaded into the reactor and allowed to self-heat while the temperature and gas profiles within the coal pile are monitored. The gases evolved from the coal are analysed using a fixed gas monitor system and gas chromatography to determine which of the common mine fire indicators and ratios can be used to predict the onset and progress of coal heatings. Benchmarking of the inherent propensity of a coal to spontaneously combust at both the large- and laboratory-scale is also possible by comparing the sample against previously tested samples. It has been found that the coal particle size affects both the time it takes for the coal to react and the location of the developing heating. The heatings generate approximately one metre from the inlet but in the crushed coal case do not progress to an advanced heating stage until the æhot spotÆ migrates towards the coal surface where there is an increased oxygen supply. Physical properties such as the compressive strength of the coal also affect the heating size and the time it takes for a heating to develop. Higher strength coals appear to oxidise more slowly and therefore take longer to self-heat as oxidation of the coal is the heat-generating step in the spontaneous combustion process. The best indicators of the state of the heating were found to be CO make and GrahamÆs ratio which are independent of air flow. Investigation of a potential spontaneous combustion should begin as soon as the CO make or GrahamÆs ratio exceed the background levels. The results from the tests undertaken on a number of Queensland and NSW coals are reported here together with the implications for the mining industry.

Jan 1, 2005

A broker relies heavily on mineral valuations and independent experts' reports to provide the fundamental information, both technical and commercial, which provides the basis of estimating the sharemarket value of securities and underlying assets. It is important to appreciate the significant variance that can occur between the market value and other types of valuation at a particular point in time. In general, most experts' reports and valuations seek to provide estimates of technical/fundamental or ""fair"" value which correspond to the Corporations Law and accounting standards requirements. They do not usually attempt to estimate (stock) market values and it is usually and quite correctly the broker's task to estimate market values on the basis of a technical appraisal and consideration of all other commercial, market and financial influences. Therefore ideally, an independent experts' report or information memorandum will include material relating to commercial and management aspects of a company as well as detailed technical reviews and fundamental valuations. Wherever sensible cash flow projections can be made, cash flow-derived valuations, usually based on discounted cash flow (DCF) calculations, remain the preferred valuation methodology. Brokers in general would not argue with this preference. However, there is a paucity of examples of valuations where alternative methods are applied as a check on the reasonableness of a DCF-based estimate.

Jan 1, 1994

By Noller B. N, McGill R. A

The Alligator Rivers Region has been the scene of one of Australia's most intensive environmental monitoring efforts since the current generation of uranium mining was mooted in the 1970s. Prior to mining, the local environment and the nature of potential impacts were not well known. The initial monitoring programs therefore included large baseline characterisation and research components. After some 15 years, water, soil and sediment monitoring programs have been reduced to a fraction of their early size, as the mining and natural systems became better known and characterised, and the actual nature of the environmental impacts were established. Modem techniques allow much more rapid and thorough identification of chemical species and elements of concern, allowing much more focused monitoring programs to be designed. In the 1980s data collection was emphasised at the expense of interpretation, and monitoring programs were maintained at much higher levels than were in fact required. It is now clear that investigations are important and should be distinguished from monitoring programs, and that the timely interpretation of investigations and implementation of recommendations can greatly reduce the effort and expense that can be involved in a monitoring program. Monitoring programs based on a sound understanding of potential environmental impact may then be efficient and cost-effective, yet provide sufficient information to assess the environmental impact of mining, guide further environmental protection measures when problems are detected, and demonstrate compliance with regulatory requirements.

Jan 1, 1994

By Grieveson P, Terry B. S

Carbothermic reduction of sulphide minerals for achieving a selective separation of metallic species from complex minerals has been discussed by considering the prevailing oxygen potential during the course of reaction. Construction of univariant plots for the reduction of sulphides with carbon monoxide gas or carbon and in the presence of either lime or anhydrous calcium sulphate is the key feature of this work. The theoretical calculations for univariants in the Cu-Fe-S-O system indicated a preferential separation of metallic copper and iron by imposing a chemical potential. This is evident from a logarithmic plot of sulphur dioxide partial pressure against reciprocal temperature. The results are compared with empirical data for the reduction equilibrium. The reduction behaviour of the constituent sulphides are also discussed together with the experimental results and theoretically predicted phase stability diagrams.

Jan 1, 1992

By B C Tanda, E A. Oraby, J J. Eksteen

"Base metal and precious metal deposits are well known for their significant geometallurgical variation throughout the volume of the proven resource. At the metallurgical level, the plant normally processes an upper oxidised layer, a transition zone and a sulfide zone, often leading to different processing techniques for the different zones. A novel processing approach is presented whereby alkaline leaching with glycine is used to leach base and precious metals, using a copper-gold ore deposit as a case study. Glycine is a cheap, non-toxic, non-volatile, highly water-soluble crystalline solid produced industrially in bulk quantities. As a chelating ligand it forms a number of stable glycinate complexes with Ni, Co, Cu, platinum group metals (PGMs), Au, Ag, Zn, Pb, Hg and Cd, with broad stability regions over an extended temperature-pH-Eh range, allowing dissolution of these metals in the neutral and alkaline regions (pH 7–13). It has been shown that this lixiviant system can leach the metals from their oxide, oxy-halide, basic sulfate, carbonate, native and various sulfide forms, including refractory sulfides such as chalcopyrite. Extraction of the metals from their soluble glycinates is easily achieved using a range of solvent extraction and precipitation processes, and the glycine remains stable in aqueous solution for recycle and reuse. Minerals bearing metals in Groups 1 to 8 of the periodic table are normally unaltered. This technology therefore provides a highly selective leaching environment for the extraction of numerous scarce metals of economic interest, with minimal interaction with gangue minerals, whilst using environmentally benign reagents. Problematic leach residues such as jarosites, elemental sulfur and silica gels are averted through this processing approach. This technology allows hydrometallurgical processing that is much less domain-sensitive in the geometallurgical sense, and utilises essentially the same key reagents for the whole deposit.CITATION:Eksteen, J J, Oraby, E A and Tanda, B C, 2016. Developing Robust Hydrometallurgical Processes to Recover Metals from Deposits with Large Geometallurgical Variation, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 15–20 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By J J. Cilliers, K Hadler

Air is fundamental to flotation; not only is it required to collect the valuable particles, but it also controls the froth stability and consequently the separation performance for a given feed. Froth stability can be described and quantified in numerous ways, which are subtly different. Air recovery is one such measure of froth stability which accounts for both the stability of the bubbles and the mobility of the froth. The benefit of using air recovery as a measure of froth stability is that it exhibits a peak as air flow rate is increased, and this corresponds to the air rate at which the optimal separation performance is obtained. As such, it provides a single target value for optimising air flowrate for a given set of feed conditions. Use of air recovery, however, has one potential drawback: accurate measurement of the inlet air flow rate to a flotation cell is required. This can be problematic for operations, particularly where calibration of air flow rate is carried out infrequently or where there is no air flow rate measurement, such as for many self-aerated flotation cells. To this end, we present an alternative method for determining the peak in air recovery (PAR) air rate.We introduce a simplified method for determining the PAR air rate using trends in froth velocity and overflowing froth height, both of which are readily measured using existing froth image analysis systems. We will show, using industrial data, the application of this simple technique to find the optimal air flowrate for flotation cells. We will also discuss other alternative techniques for air rate optimisation that have the potential to improve separation performance using existing technology.CITATION:Hadler, K and Cilliers, J J, 2018. How to find the optimum air rate for flotation cells, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 377–384 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By J T. Smit

The theory of froth flotation developed slowly, in almost all cases lagging behind practical developments in the operation of flotation processes. This was largely the result of a lack of understanding of the required basic principles of chemistry and physics, many of which were being developed at the same time. A review of some of the early theories propounded is worthwhile, and should encourage those who are presently studying or practicing flotation to exercise some care in claiming a complete understanding of the underlying phenomena in the art. This paper considers theories presented up to and including those in Principles of Mineral Dressing by Antoine M Gaudin (1939). Of course, developments since that time are important, but they are beyond the scope of this discussion.

Jan 1, 2005

By C Ausa, Nyunt Htay, A, L Deiparine

The main tectonic elements in Myanmar are a late Mesozoic and Cenozoic magmatic arc system in the west, repeated in northern Myanmar by more than 300 km of dextral movement on the Sagaing Fault, and the back-arc continental region affected by early and late Mesozoic orogenies, in the east. Historically most lode gold production has been from latest Cretaceous high-grade mesothermal veins and derived placers in the Wuntho and Tagaung-Myitkyina segments of the magmatic arc. Placer deposits in the Ayerwaddy River north of Myitkyina are currently worked by more than 100-bucket dredges. South of Wuntho, the magmatic arc and Pegu Yoma fold belt host epithermal gold with associated As, Sb and Zn in mid-Tertiary marine sediments. MyanmarÆs most productive lode gold deposit, the Kyaukpahto mine, lies within a north-trending district east of the magmatic arc and north of Mandalay. Here mineralisation and associated jasperoidal silica occur in Eocene sandstones and Permian and Triassic carbonates. Possibly this district continues southeastwards, across the Sagaing Fault, as sediment-hosted Sb Au and locally skarn Au mineralisation within a 1100 km long fold-thrust belt. Also present in the back-arc region are sandstone-hosted Au Cu in a Palaeozoic slate belt, and gold and stratabound gold-base metal mineralisation in the medial metamorphic belt. While untested targets remain in the magmatic arc, particularly for high sulphidation Au, the best potential is clearly within the back-arc slate and fold-thrust belts in the western part of the Shan Plateau and in northeastern-most Myanmar.

Jan 1, 1999

By Mine F. J, Woods P. H

The Top End of the Northern Territory lies in the monsoonal zone and receives rain during the November-April period. Initially, at the start of the wet season, rain storms are localised, but, following the descent of the monsoonal trough from below the equator, widespread rain occurs. Overflow incidents at mine sites tend to arise midway through the annual wet season when excess water accumulated in ponds begins to discharge to the external environment. Remote-access monitoring may be undertaken at mine sites using equipment to continuously measure water quality parameters with storage of the information on a data logger. The data is then retrieved by visiting the site and transferring it to a portable computer or by remotely accessing the system using a telemetry system and transmission via telephone, VHF/UHF or satellite. Such systems are readily available and vary in cost depending on the sophistication of the data transfer system. Available sensors for continuous monitoring include those for conductivity, temperature, pH and other ion selective electrodes, eg nitrate, and water level. Of these variables, conductivity is most useful due to its inherent accuracy and stability of reading. Remote monitoring capability is able to provide: (i) more intensive monitoring of key issues; (ii) more timely information; (iii) correct perspective on the degree of environmental problem; and (iv) information from remote locations, which would be difficult to monitor by more conventional methods. Examples are given for applications of continuously logged measurement of conductivity of waters discharging to drains and in creeks at Pine Creek, Ranger, Nabarlek and Woodcutters mines in the Northern Territory. These applications demonstrate the timeliness of the continuous monitoring technique.

Jan 1, 1994

By B Manda, K L. Sandvik, K Musiwa

Mining and processing of pyrite ore at Iron Duke Mine, north east of Zimbabwe, generates large quantities of acidic mine water as a result of the oxidation of iron sulfides on exposure to air and water used in the drilling and blasting operations. The acid mine drainage (AMD) contains elevated levels of dissolved Fe, Al, Mn and sulfate and has characteristic pH values ranging from about 0.50 to 3.00. Handling and disposal of such a drainage places significant impacts on the economics of the mining operation due to the corrosive nature of the drainage on infrastructure, the limitations placed on water reuse and discharge to the environment under a new law governing effluent discharge. Treated sludge at Iron Duke is chemically unstable, changing pH from ~7 to ~3 within four days after deposition in the evaporation ponds. The effluent does not meet the permitted level of neutral pH, 500 mg/l sulfate and less than 2000 mg/l total dissolved solids. Excessive acid seepage from the evaporation ponds has resulted in contamination of the ground water below the ponds area, which shows high mean annual levels of iron (368.67 mg/l), sulfate (1702.89 mg/l) and low pH (2.86) in addition to other pollutants. This poor quality seepage infiltrates into the nearby Yellow Jacket River, contaminating the public water source. Furthermore, a deterioration of the land area and vegetation adjacent to the tailings dump is also observed. Understanding the controls on the neutralisation of acidic drainage and long-term sludge stability after placement in evaporation ponds is essential to minimise costs of closure requirements and for the protection of environment and human health. This study examined the effects of the master variables pH, redox potential, acidity and alkalinity on acid neutralisation. The results indicate that ferrous hydroxides are not as stable as ferric hydroxides and that proper oxidation of iron also leads to better sludge stability, higher treatment efficiency and a manageable sludge viscosity. Metal hydrolysis and secondary mineral formation at the evaporation ponds under a wide range of pH and redox conditions is responsible for equilibrium shifts in metal reactions, resulting in high potential for metal leaching and mobility. Mechanisms of metal attenuation are also discussed.

Jan 1, 2006

By R Stosch, D Lohberger, J Rodler, E Schnell and A Bassler, H Ramseier

In the last two decades three-dimensional (3D) computational fluid dynamics (CFD) simulations have become an important tool in engineering sciences. More recently, the safety requirements in underground railway stations have increased with regard to incidents. For this reason, existing underground stations (eg Munich, Strasbourg and Berlin) are being equipped with smoke extraction facilities to protect passengers from smoke and visibility impairment in the event of fire. In addition, designs of planned underground stations (eg Karlsruhe, Doha) also include these facilities.For the commissioning of ventilation engineering systems with complex structures, the functional testing of the whole technical installation are important, as are the acceptance tests of ventilation and equipment parts. This functional testing includes not only the technical inspection of the equipment but also the acceptance measurements of the capability of the equipment and the execution of hot- or cold-smoke tests to confirm the effectiveness of the ventilation system.Due to the fact that the overhead contact line and other sensitive installations were already installed in the tunnel roof at the time that smoke tests were proposed, hot-smoke tests with fire loads up to a maximum of 1 MW could only be executed. Therefore, the evidence of the attainability of the safety objective had to be provided computationally in this special case with a fire scenario of a heat release of 10 MW using CFD simulations.This paper presents the interplay between the results from acceptance testing and smoke tests and the use of 3D CFD simulation and virtual reality using the example of Allmend station, which was repositioned underground and is part of a new section of track from Lucerne railway station to Kriens in the Zentralbahn network. The steps of the verification and validation of the computer model are presented with the real tests and measurements.CITATION:Stosch, R, Ramseier, H, Lohberger, D, Rodler, J, Schnell, E and Bassler, A, 2014. Safety in underground railway stations – an example of the interplay between testing and 3D computational fluid dynamics simulation, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 103–112 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By B W. Ham

The legacy of underground coal mining may be a land surface which, in parts, may be unstable in the long term. A case study analysis has been undertaken to explain some of the hazards and how the risk may be assessed and managed.The Ipswich Coal Measures were extensively mined with shallow underground workings, which now underlie a number of suburbs in the eastern side of the city of Ipswich in south eastern Queensland. The area was subject to underground mining from the 1840s to 1997. In general, the mines were small, family-owned operations that were restricted by complex geology, interactions with neighbouring operations and ownership of surface facilities. The oldest available mine plans date back to the late 1890s.The residents in these mining areas have a long history of unexpected mining subsidence events. A level of risk management for property owners has been implemented by the Ipswich City Council, which requires a mining subsidence risk assessment to be submitted as part of building applications for property development in the areas suspected of having mining subsidence risk. This discussion examines a series of generic subsidence events and how the risk may be assessed and managed and the hazard controlled.CITATION:Ham, B?W, 2014. The legacy of underground coal mining – mine subsidence: Ipswich coal measures case study, in Proceedings Life-of-Mine 2014 , pp 113–120 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

The paper continues an account, begun in a previous paper, of experimental work carried out by the author whilst a member of the metallurgical staff at the Cockle Creek Works. The general method of the description of the plant and works practice adopted previously has been followed.The paper is a short account of the methods used in and the results of an investigation of the fume losses from the various parts of the plant.MEASUREMENT OF VOLUMETwo independent methods were used. The first depended on a number of pitot-tube measurements of velocity. These readings were taken in the stacks leading from the various furnaces at a considerable height above the ground so as to obtain as regular conditions as possible at the points where the readings were taken.Three openings were made in each stack and the pitot tube inserted into each opening in turn and readings taken at the centres of imaginary areas of equal size. The average velocity in the stack was thus obtained.After four tests had been made at the smelter stack, which removed the gases from all blast furnaces in use, the centre of velocity of the gases for each test was calculated and was found to be practically constant in position. The previous procedure was varied in subsequent tests on this stack by taking a succession of readings at the centre of velocity instead of at various points...

Jan 1, 1925

Opening AddressThank you for inviting me here today to open what promises to be a significant conference on the technological aspects of extractive metallurgy. I would especially like. to welcome delegates who have travelled great distances in order to contribute to, and be participants in, this examination of the technical innovations which have always been a crucial part of our industry.

Jan 1, 1992

By K G. van den Boogaart, U Mueller

"An accurate prediction of benefit for some types of ore may require not just the ore grade, but a whole compositional characterisation of the estimates; that is, its full mineral composition including waste composition and nuisance elements. An example is Nickel laterite ores, where Ni/Co content must be complemented by estimates of many other elements, as these might have a notable impact on ore processing.Estimates are often obtained with (co-)kriging or co-simulation; however, geostatistics applied to compositional data may yield spurious and inconsistent results because of the constant sum constraint. The log-ratio approach avoids such problems. It proposes a three-step procedure: data are mapped to a set of log ratios of components; for example, the additive log-ratio transformation (alr) transformed scores are modelled with an appropriate fully multivariate geostatistical toolbox; for example, direct/cross-semivariograms and co-kriging or co-simulation results are back-transformed to the original units.Some practical aspects may make the application of this technique difficult: the assumption of Gaussianity and the high dimensionality of the compositions combined with the need for using multivariate methods. This contribution compares several ways of treating compositional data (combining normal score transformation, log-ratio transformations, and minimum/maximum autocorrelation factor (MAF) decomposition) with respect to their ability to generate sensible simulations. The various approaches considered are illustrated with a Nickel laterite data set for which ten variables are available. Both theoretical considerations and illustration results suggest that the best combination is (log)ratio-normal score transform-MAF, in this order. The factors so obtained are closer to Gaussian, approximately spatially decorrelated and can be simulated independently. Simulations can later be recombined to alr-simulations, which in turn may be converted back to point compositions. The resulting simulated compositions are compared with a full Gaussian co-simulation of the raw data. The log-ratio methods show reasonable to good reproduction of mean values, and distribution of the data set and by construction satisfy the total sum constraint, in contrast to the simulations based on raw data for which the total sums fluctuate strongly.CITATION:Mueller, U, Tolosana-Delgado, R and van den Boogaart, K G, 2014. Approaches to the simulation of compositional data – a nickel-laterite comparative case study, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014, pp 61–72 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 24, 2014