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Using Mineral Maps to Rank Potential Processing Behaviour

Sep 13, 2010

Controlled Source Audio Magnetotelluric (CSAMT) surveys were carried out by Glass Earth (New Zealand) Limited (Glass Earth) in 2006 - 2007 to investigate epithermal gold targets in the central North Island of New Zealand. The surveys were conducted using a Zonge GDP 32 8-channels receiver and a Zonge XMT 32 transmitter powered by a 16 KW generator. The electric field dipole was maintained at 20 m length (five dipoles per 100 m spread) and the frequency ranged from 4 KHz to 4 Hz. Only scalar (TM mode) signals were recorded, using one magnetic coil per spread. The transmitter bipoles were 1 - 4 km in length and located about 5 to 10 km from each survey area.   Sixteen individual target areas were surveyed by June 2007. The CSAMT survey lines (100 - 400 m spacing) were determined mainly on results from previous ultra-detailed airborne magnetic and gravity surveys conducted by Glass Earth in 2005. The data from each CSAMT line was carefully examined to remove any spurious signals and processed using Zonge SCS2D software, which can produce smooth 2D resistivity inversions of the field data. The results were presented as resistivity sections and maps to help the identification of exploratory drilling targets, mainly from the existence of subsurface high resistivity zones (resistors) that can be interpreted as caused by silicification associated with epithermal mineralization.   An example of processing and interpretation of the CSAMT data is presented in this paper on results from Glass EarthÆs Tahunaatara target, where CSAMT surveys have identified zones of epithermal mineralization confirmed by exploratory drilling.

Jan 1, 2007

By H W. Wu, D Humphreys

The structure of a comprehensive research project into mine fires study applying the Ventgraph mine fire simulation software, preplanning of escape scenarios and general interaction with rescue responses is outlined. The project has Australian Coal Association Research Program (ACARP) funding and also relies on substantial mining company site support. This practical input from mine operators is essential and allows the approach to be introduced in the most creditable way. The effort is built around the introduction of fire simulation computer software to the Australian mining industry and the consequent modelling of fire scenarios in selected different mine layouts. Application of the simulation software package to the changing mine layouts requires experience to achieve realistic outcomes. Most Australian mines of size currently use a ventilation network simulation program. Under the project a small subroutine has been written to transfer the input data from the existing mine ventilation network simulation program to æVentgraphÆ. This has been tested successfully. To understand fire simulation behaviour on the mine ventilation system, it is necessary to understood the possible effects of mine fires on various mine ventilation systems correctly first. Case studies demonstrating the possible effects of fires on some typical Australian coal mine ventilation circuits have been examined. The situation in which there is some gas make at the face and effects with fire have also been developed to emphasise how unstable and dangerous situations may arise. The primary objective of the part of the study described in this paper is to use mine fire simulation software to gain better understanding of how spontaneous combustion initiated fires can interact with the complex ventilation behaviour underground during a substantial fire. It focuses on the simulation of spontaneous combustion sourced heatings that develop into open fires. Further, it examines ventilation behaviour effects of spontaneous combustion initiated pillar fires and examines the difficulties these can be present if a ventilation reversal occurs. It also briefly examines simulation of use of the inertisation to assist in mine recovery. Mine fires are recognised across the world as a major hazard issue. New approaches allowing improvement in understanding their consequences have been developed as an aid in handling this complex area.

Jan 1, 2005

By J Krnmmelbein, T Raab

In Lusatia, lignite mining causes major disturbances on the landscape scale. Reclamation procedures are applied to recover the reconstructed landscape for different land use options. In this study we investigate soil physical properties of an agricultural reclamation/recultivation site directly after site restoration and the development of selected parameters within the first years after site restoration depending on varying recultivation strategies.The sandy substrates used for recultivation stem from depths of several meters. They are unstructured, free of recent organic matter and have high contents of calcium carbonate. During reconstruction and most of all during surface levelling with heavy crawlers, the substrate?undergoes high mechanical stresses. This leads to partly severe soil or substrate compaction, depending amongst others on substrate water content and mechanical stresses during site construction. We investigate the effect of different organic soil amendments, different crop rotations and partly subsoiling on the development of soil structure. We compare results of laboratory measurements directly after site construction before any reclamation measures had been applied to results we gained after three and four years of recultivation. The results show that after the earthworks are completed, the site is strongly heterogeneous in relation to mechanical stability, permeability for air and water, pore volume and bulk density. The results after three and four years show that the heterogeneity of soil physical parameters decreases. The selection of suitable crop rotations superimposes the affects of other reclamation measures, eg varying organic fertilisers or deep loosening.CITATION:Krnmmelbein, J and Raab, T, 2012. Reclaimed lignite mining areas A73 in Lusatia - Development of soil physical parameters of an agricultural site within the first years after site reconstruction, in Proceedings Life-of-Mine 2012 , pp 117-122 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By A Jewbali, J Phillips, C Boyle

Normal practice in the mining industry is the creation of a single geological model. These models provide a single interpretation of the geological and mineralisation domains. These interpretations infer the exact behaviour of ore domain contacts at shorter scales when resource definition drilling is done on wider scales and are thus locally highly uncertain. The interpreted geological model provides a single number for the volume and tonnes of mineralised material enclosed by the mineralisation envelope. It is on this single number for volume and tonnage that capital intensive mine development decisions (mine design and scheduling, stockpile strategy, waste management, closure planning, dewatering strategy, product quality, etc) are based. Some of these decisions require knowledge of grade variability for small volumes of material such as quarterly production periods. It is generally recognised that this information cannot be derived from single kriged geological models, but can potentially be modelled by conditional simulation techniques. Uncertainty in the extent and continuity of the mineralised envelope and its effect on grade variability for shorter production periods is thus recognised as a major source of uncertainty in new mine development.CITATION:Jewbali, A, Boyle, C and Phillips, J, 2013. Quantifying domain uncertainty for an iron ore deposit, in Proceedings Iron Ore 2013 , pp 157-168 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Dippenaar R, Evans T

Twin-roll continuous casting technology is rapidly approaching commercialisation. Fundamentally different than conventional continuous casting, heat transfer and hence solidification during twin-roll casting are governed by the interfacial melt/mould thermal resistance, as opposed to the resistance of the solidifying shell. Under these conditions the interface resistance is predominantly controlled by the melt/substrate wetting behaviour. The very early stages of melt/mould contact are characterised by highly transient heat transfer conditions. The overall melt cooling rates prior to the formation of the first solid are reported to be in the range of 1000 - 50000 K/s with melt undercoolings of up to 300 K. At the points of intimate melt/mould contact the thermal resistance is approaching zero, where cooling rates and undercooling much larger than those reported in the literature are probably occurring. Improved wetting will reduce the energy barrier for nucleation while at the same time increasing the cooling rate of the liquid. Since the overall nucleation rate is controlled both by the rate of cluster formation and the rate of atom transfer to the nucleus, a critical cooling rate will exist above which the nucleation rate is expected to be reduced. Under these conditions, it is possible that the first solid phase to form is a metastable glass which subsequently transforms into a crystalline phase. The implications on nucleation and early growth are also discussed.

Jan 1, 1999

Willyamite from the type locality, Consols mine, Broken Hill, N.S.W., has been re-examined, and found to consist of zones with widely different Co:Ni ratios. The name willyamite is redefined to include the portion of the (Co, Ni)SbS series with cobalt in excess of nickel. Willyamite is pseudo-cubic, with the three axes equal to within 0·001 A.

Jan 1, 1970

The history of zinc production in Australia is outlined including attempts to make zinc electrolytically at Cockle Creek, N.S.W. in the last century, the use of horizontal retorts at Cockle Creek and Port Pirie, South Australia, production by electrolysis at Risdon, Tasmania and at Port Pirie using zinc oxide fumed from lead blast furnace slag and production by the Imperial Smelting process at Cockle Creek. Developments in the electrolytic process are described including those in roasting, acid manufacture, leaching, purification, electrolysis, melting and casting. The Imperial Smelting process technology is also outlined. In both processes global technology is reviewed, including important Australian contributions.

Jan 1, 1986

Study on Selective Reduction and Magnetic Separation of Low-Grade Nickel Laterite Ore to Produce High Nickel Concentrate

Sep 13, 2010

Understanding multiphase particulate systems is essential for the further advancement of mineral processing technology. Characterisation, analysis, and simulation of these complex systems provide a fundamental basis for the development of improved mineral processing technology. One of the more recent tools that can be used to help provide a foundation for improved mineral processing technology is high resolution cone beam X-ray micro computed tomography (CT). During the past ten years point-projection X-ray micro CT systems have been used for 3D visualisation and quantitative analysis of multiphase particulate systems. Analysis of packed particle beds containing as many as 30 000 particles can be accomplished in less than three hours with special software to establish the 3D characteristics of each particle in the population and the spatial organisation of the packed particle bed. Now, due to advances in X-ray optics, the resolution afforded with point-projection micro CT systems has been improved by at least an order of magnitude using a lens-based X-ray micro CT system. The development of software tools for the 3D characterisation, analysis, and simulation of packed particle beds using high resolution X-ray micro tomography (HRXMT) is discussed including examples of application in the areas of comminution (particle damage and preferential grain boundary fracture), exposure/liberation analysis (liberation-limited separation efficiency, including coal washability), and filtration/heap leaching (pore network structure of packed particle beds and simulated flow using the LB method of computational fluid dynamics).

Sep 13, 2010

The paper outlines the development and objectives of the slim core (50 mm dia.) testing procedures employed at the Company's Central Research Laboratories with particular reference to washability studies required for coalfield evaluation. It shows that when the routine test procedures, that have been developed for cores recovered form the Sydney Coal Basin, were applied to Bowen Basin Coals some of the washing data obtained appeared to be suspect. Though yield indications appeared to be of the right order, product ash, required separating gravity and percentage of near gravity material were found to be at variance with bulk washability data. The results of a correlation study made on an underground seam from the Bowen Basin comparing slim core, hulk sample, and pilot plant washing data are given. The results of a series of studies including washability studies made on slim cores, strip samples, large diameter cores and bulk samples, pilot washing trials and computer simulations of washery circuits treating Lilyvale seam coal from the Bowen Basin are shown.

Jan 1, 1977

The quality of the external water source for a mineral processing plant may influence the extent to which the environmentally desirable practice of recycling of water from plant products is possible. This is particularly likely for froth flotation plants where the chemical quality of the water may affect the plantÆs performance. The quality of the external water source or the recycled water can be improved by a water treatment step, and in turn the extent of recycling which can be tolerated is able to be influenced. The quality of the external water can range from very high quality, soft water derived from melting snow, to poor quality, hard water (high levels of dissolved calcium and magnesium) from underground aquifers, and to even lower quality sea water (very high levels of dissolved species including sodium chloride). It can be noted that some underground water is more saline than ocean water as well as containing high levels of dissolved calcium and magnesium. Occasionally, a different source of water is utilised in the wet and the dry seasons. Increasingly, sewage water from cities is becoming a potential external water source with sustainability implications. If the initial quality of the external water is high, the scope for recycling of water from all the products is maximised. Such reuse or recycling of water from the products allows chemical species from oxidation of the ore and from other inputs to the process such as reagents to increase in concentration in the water returned to the plant. Such accumulation of species can have negative effects on the performance of a process such as froth flotation but instances of positive effects exist. Some reagents which are used in flotation plants such as lime or sodium carbonate also happen to be commonly used for independent water treatment plants. Hence, the flotation process may inadvertently provide some aspects of water processing. Where the quality of the water in the feed to a mineral processing plant (external water plus recycled water) is not an issue, more powerful solid-liquid separation processes can be considered to maximise the removal of water from the products and its reuse. Such processes may also have complementary benefits in a sustainable mineral industry by, for example, producing a tailing stream with a higher per cent solid value which is more suitable for safe storage on the surface or underground. This paper documents findings on the effect of water quality on the flotation process. It also considers current directions of change in the need for increased removal of water from plant products. It then considers the implications of these trends for maximisation of water recycling by such operations.

Jan 1, 2003

By C Maloloy-on, S Morgan, M Deiparine, H Mackie

There is a strong focus in the mining industry to limit its impact on water quality and usage. This is even more evident in developing countries, where mining companies operate within local communities and have to be diligent not to affect them negatively. In mineral processing operations, the vast majority of water reclamation occurs at the tailings thickener area and tailings storage dam. It is often more effective to maximise water recovery at the tailings thickener before material transport to the tailings dam. Tailing dams are relatively inefficient, and experience a high degree of water loss due to evaporation, seepage and water retention. In addition, tailings dams present the biggest environmental liability for mineral resource projects, so it is beneficial to limit their size and loading.In the past, it was common for tailings thickener areas to have a significant footprint with several large diameter conventional thickeners, producing underflows of between 45-55% solids (w/w). At times, these multiple thickeners were difficult to operate, leading to inefficiencies in water recovery and quality. The development of High-Rate Thickeners (HRT) has resulted in improved settling properties and HRTs usually operate at significantly higher solids loadings (= 1.2 t/m2.h) when compared to conventional thickeners (= 0.1 t/m2.h). Subsequently, thickener diameters have reduced in size and HRT technology has become the preferred option for thickener circuit design in both new and existing operations. HRTs also produce higher water recoveries with increased underflow densities = 55% solids (w/w).The Carmen Copper Corporation (“Carmen Copper”) circuit upgrade is a recent example of these HRT benefits, where one, 39 m diameter, Outotec HRT treats the solids flow rate of five 76 m diameter conventional thickeners. This has allowed operations to increase dry plant tonnage by 50%, maintain key performance targets and provide a framework for further plant expansion. This paper details the sustainable approach to the Carmen Copper tailings thickener upgrade, where metallurgical performance, cost-effectiveness and environmental impact were key considerations.CITATION:Morgan, S, Mackie, H, Maloloy-on, C and Deiparine, M, 2015. Carmen Copper – a sustainable approach to tailings thickener upgrades, in Proceedings MetPlant 2015, pp 416–430 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

Statistical frequency distributions may be used to characterize the overall variation of grade in orebodies. Special types of distribution (e.g. lognormal, log-type A) are necessary to describe skewness inthe case of rare metals. Also needed (but for the most part hitherto neglected) is the serial correlation function which describes the tendency for grades near together in an orebody to be closer together than grades at points relatively far apart.The sampling problem for orebodies is interpreted in statistical terms. Different methods are reviewed, and the effect of serial correlation discussed.A discussion is given, based on experiments and observations made by the author, of biases arising in the minei:l material by such methods as chip sampling and grab sampling due to such causes as nonrepresentative selection by the sampler.INTRODUCTIONMiners have always recognized the large element of chance in their operations. Chance is the raw material of statistical theory and, provided there is some recognizable pattern or underlying regularity in a set of data arising from the operation of chance events, statisticians are able to formulate mathematical models to study them. Mining engineers, geologists, and statisticians have gone a long way between them towards finding general statistical rules which describe the distribution of minerals and metals in orebodies, and even the distribution of orebodies over the earth's surface.These rules do not have the force of physical laws, though they obviously derive from them and have been used to throw light on them. From statistical theory it is possible to find methods of estimating from sampling some of the characteristics of orebodies which are of importance to...

Jan 1, 1962

By Robinson BW, Walker RK

Using a new highly stable automated electron microprobe analyser, detection limits for gold in arsenopyrite have been improved. Using the AuLA emission tine at 40kV and 500nA, a limit of approximately 10gpt is attained in 10- lSmins. Some unusual features of the background need to be taken into account. Several ores containing different levels of gold in arsenopyrite have been examined, and it has been shown that gold is not evenly distributed between grains (some may contain more than 1%, invisible optically), and that the grains containing gold are often zoned. Gold may be released from the arsenopy rite by weathering or by heating in an inert or slightly oxidising atmosphere.

Jan 1, 1989

By Rayner B

Five wells have been drilled in the Basker/Manta Block of VIC/P19, Gippsland Basin, resulting in sub-economic Intra-Latrobe Group oil and gas discoveries at Basker-1 and Manta-1. A total of 21 individual hydrocarbon bearing sandstones were intersected by the two wells. These reservoir sand bodies were deposited by fluvial processes in a lower coastal plain environment. The modelling of sand body orientation and geometry is a critical component in the evaluation of the two accumulations. Seismic resolution of the thin (average 2 m to 5 m) sand bodies is inadequate for mapping their orientation and distribution. Dipmeter data has been successfully applied to the problem of orienting the sand bodies using FMS images acquired during the drilling of Gummy-1 and reprocessed HDT data from Basker-1 and Manta-1. Prediction of lateral extensiveness (geometry) of individual sand bodies has also been attempted. Interpreted palaeocurrent direction from all three wells is dominantly from the NW to the SE. Reservoirs in the Manta-1/Gummy-1 area are interpreted to be predominantly channel sands, deposited by relatively low sinuosity streams. As such they would tend to have a laterally extensive, elongate geometry. Sand bodies deposited in the Basker-1 area show a predominance of laterally accreted cycles deposited by meandering streams. Channel geometry may then be limited in the downstream/upstream direction by internal permeability barriers such as clay plugs.

Jan 1, 1992

The Rate Variable Batch Test (RVBT) - A Research Method of Characterising Ore Floatability

Sep 13, 2010

The placer mining industry of the West Coast region of the South Island is based largely around the production of alluvial gold, although other valuable minerals are also present. Since the first major discoveries in 1864-65, reported gold production has totalled around 264 t (8.5 Moz). During the past 10 years, annual production has totalled around 1460 kg (47,000 oz). It is anticipated that gold production over the next three years will continue at a level of 1400-1800 kg.   Annual gold production peaked during 1866 at approximately 17,170 kg (550,000 oz) and has not exceeded 100,000 oz since 1885. This reflects the ease with which gold was won from shallow, rich deposits that were present at many localities. Subsequently, there has been a general decline in the availability of this type of deposit, a trend that will continue in the future. This paper outlines the present state of placer mining in the West Coast region, gives some historical background to the industry and briefly predicts future trends.

Jan 1, 1997

By M Tayebi-Khorami

There is an increasing trend in the extraction and development of copper resources from complex deposits. The complex deposits pose mineral processing challenges, as they often contain low grade copper ore, relatively large quantity of clay minerals, complex texture, very fine disseminated ore, high amount of pyrite, and high level of impurity elements such as arsenic. With the amount of arsenic in concentrates increasing and with environment, occupational health and safety regulations becoming more restrict, there is a need for a processing method that results in no arsenic emissions and captures all arsenic while immobilizing it in a compound that is stable under a wide range of conditions, so it is suitable for long-term disposal. Some development work has been undertaken to examine the most effective arsenic treatment option for complex orebodies that contain arsenic, but a technically robust and economically viable option has not yet been developed. Previous research has demonstrated the possibility of separating arsenic-copper sulphides from other copper minerals by controlling the potential of the flotation pulp in the single mineral systems. The selective flotation of enargite from copper sulphides in a real complex ore system was studied by Tayebi-Khorami (2016), which is summarised in this paper. CITATION: Tayebi-Khorami, M, 2018. Arsenic in complex orebodies, in Proceedings Complex Orebodies Conference 2018, pp 132–134 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

A magnetometer survey 'was the Darkes Forest area between 1968. The instrument used was model MZ4 with sensitivity 9.4 conducted over part of 30th April and 3rd May, an ABEM torsion magnetometer gammas per scale division. The survey consisted of a closed magnetometer loop along lines cut for a previous magnetometer and seismic reflection survey by Wongela Geophysical in March, 1968. The magnetic results of the previous survey were not satisfactory in some areas and are presented as a comparison in instrumentation. Station separation in the present survey was 100 feet with tie-in readings at shot points of the previous survey (usually 1320 feet apart)

Jan 1, 1969