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By Teague JK, Read HW

The relationship between the maceral composition of coal and the strength of the coke produced from that coal has received a great deal of attention in recent years. Studies using two Bulli Seam coals, and blends of Bulli and Wongawilli Seam coals, from the Illawarra Measures of the Southern Coalfield of New South Wales were carried out. The optimum range of vitrinite was found to lie between 45% and 60% (mineral matter free). Above and below this vitrinite range coke strength deteriorated. I Coke strength indices increased with rank and the optimum vitrinite content increased with an increase in rank. These changes will require confirmation as trends by testing a third level of rank. It was noted that vitrinite content decreased with an increase in the specific gravity of separation of the coal. . T Use of- petrographic analyses will increase confidence in choosing coals for coking, provided the coals are well known. Such analyses offer the possibility of greater flexibility in coal purchases and the possibility of producing a marketable blend from coals, which have limited market potential. Critical base coals for blends can be conserved. Significantly more work is required before coal reserves can be utilised to optimum advantage. This work would require extension of-the studies discussed in this paper and, in particular, the testing of a wider range of rank.

Jan 1, 1970

By S Farrokhpay, M Zanin

Although it is well understood that in flotation collection zone and froth zone are deeply interconnected, and reagents (and in particular collectors and frothers) cannot be selected without considering their synergistic effect, this concept is rarely applied in plant practice. The feed mineralogy also has an important role in how particles and reagents interact in flotation, which is sometimes overlooked by operators. In this work, a combination of batch flotation tests and froth stability measurements was used to optimise the collector and frother scheme for the flotation of a copper ore. The methodology was applied to an Australian copper plant which was experiencing high variability in froth stability in the roughers when the feed ore mineralogy was changing. It was hypothesised that chalcopyrite in the feed in combination with isobutyl-xanthate had a destabilising effect on the froth phase under the reagents scheme used. Froth stability was restored if a shorter chain length, less hydrophobic, xanthate was employed. It is apparent that the hydrophobicity of adsorbed films at the solid/liquid/air interfaces has a critical role in enhancing or reducing froth stability. Unstable froth causes a reduction in copper recovery in spite of a high collection zone flotation rate. The case study suggests that collection zone and froth zone can rarely be optimised independently of each other. With the laboratory procedure adopted, a more suitable reagents scheme was determined to respond to changes in the feed mineralogy, avoiding fluctuations in plant performance due to unexpected froth instability.CITATION:Farrokhpay, S and Zanin, M, 2012. Synergic effect of collector and frother on froth stability and flotation recovery - An industrial case, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 145-150 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By R Valenta, A Littleboy

Geological heterogeneity is one dimension of complexity in mining. Significant effort is put into developing an understanding of this complexity so it can be used in resource estimation, mine planning and economic modelling. However, over the decadal lifespan of a mining venture, many other dimensions add to the complexity of a mining operation. These include: technological evolution, market fluctuations; investor confidence; social norms; local expectations; and ecosystem functionality. As with geology, these factors are all heterogeneous, uncertain, time varying and represented through sparse and incomplete datasets. Recent work (Valenta et al) is beginning to show us how these risks correlate in different global settings. By analysing data relating to known, but as yet undeveloped copper deposits, this work (the complex ore body database) is demonstrating that it is the combination of issues (both price sensitive and non price-sensitive) that determine the viability of a deposit for extraction in the 21st century.CITATION: Littleboy, A, Plint, N and Valenta, R, 2018. Mining as a complex system: do we need a new model?, in Proceedings Complex Orebodies Conference 2018, pp 41–43 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By W Boughton, L Gilbert

The Australian Water Balance Model (AWBM) has found widespread use in Australia in estimating the streamflow behaviour of catchments. It has been used at the Ridgeway Gold Mine, in central west New South Wales, to estimate streamflows in creeks potentially affected by loss of spring-fed baseflow due to mine dewatering. The AWBM estimates are used to assess the effect of mining on streamflows and the need to provide compensatory flow releases, which would be drawn from mine water supplies, into the creeks, in compliance with regulatory consent requirements. The monitored flows in some of the creeks exhibit non-typical behaviour, with streamflows increasing in autumn months despite a lack of significant rainfall. This behaviour is believed to be due to the combined effects of discharge from rock fractures and the effects of evapotranspiration in the riparian zone. A modified version of the AWBM has been developed which much more closely simulates the observed flow behaviour and which will be used in ongoing flow assessments for the mine. This paper outlines the difficulties involved in modelling low flows in small catchments that are subject to a number of influences (other than mining), describes the development of a refined model to improve simulation of low flows and baseflow in small headwater catchments and highlights the need for good baseline data to calibrate such models.

Jan 1, 2006

By Gilligan P

The Selwyn gold-copper operation is wholly owned and operated by the Arimco mining group. The mine is located 150 kilometres south-east of Mount Isa. The primary extraction method for the gold-copper 251 orebody is by sub level open stoping. Secondary extraction is from the mass blasting of the remaining crown and rib pillars. The final mass blast of the 251 orebody occurred in December 1993. This paper details the design and execution of that firing.

Jan 1, 1994

By G De Tomi, R Sousa, A Lapworth

One of the current challenges for iron ore producers is the ability to respond to changes in ROM stockpile specifications in a quick and cost-efficient manner. The decision-making process to respond to such changes is normally associated with grade-control and short-term mine planning activities, from where new operating instructions to the mine are provided. Mines are under increasing pressure from changes in the industry, such as a scarcity of skilled staff; a higher turnover of skilled employees and tighter product specifications. The quality of operational activities easily suffers as a result of these pressures. The technology that supports operational activities is often poorly implemented, which results in systems being unsustainable and poorly understood by the organisation. All successful technology implementations rely on the people, processes and technologies involved being well understood. Because of the complex nature of mining, the processes that underpin mine planning, scheduling and operational control are often not well defined. This results in activities undertaken by individual departments being poorly integrated. Datamine has developed a set of tools and methods for decomposing; capturing and documenting processes and ensuring those are embodied in implemented solutions. A case study of such a solution is the GEROS planning system, which has been successfully implemented at CVRDÆs Southern Iron Ore System, in Minas Gerais, Brazil.

Jan 1, 2005

Australia has historically been a world leader in mining innovations. This trend is reflected in the international patent records, which show that in recent years there has been some recovery in the number of patent filings arising from Australian research. These innovations occur across a wide cross-section of mining technologies and derive from both public and private sector research. Australian mining innovations are largely dominated by new processes and equipment, principally in the areas of rock drilling and coring, strata stabilisation, cutting tools, blasting, mine design and oil field exploitation. They include improvements in drill bits, rock bolts and accessories and wellbore systems. Another area that has received significant research attention has been the in situ thermal processing of coal deposits. High profile examples of Australian mining innovations include the æSORDMinerÆ, a remote-controlled mining machine for use in mining collapsing wet environments, and CSIROÆs SMART*CUT rock cutting pick that dramatically increases the rate of cutting hard rock. This paper will provide an overview of recent innovations in Australian mining, as reflected in the international patent records, including the organisations and individuals active in the field, and the technological nature of specific innovations.

Jan 1, 2008

By Ngai WCT

Over 90 per cent of the explosives in Hong Kong are used in civil engineering works. The Hong Kong Government controls all explosives and delivers on a daily basis to each site which it has licensed. Such deliveries need to be arranged the day before actual delivery. With the vagaries of the traffic in Hong Kong, contractors do not necessarily know the time of arrival of explosives. Contractors in general would like to reduce their exposure to these potential delays and the high cost of explosives deliveries. The high population density and urbanisation means that rock blasting has to be carried out in close proximity to other property. In order to protect life, property and utilities, it is not only necessary to employ proper blasting techniques but also to adopt effective safety measures. The Route 3 Advance Earthworks project is located on the north-west corner of Tsing Yi Island, Hong Kong. It is one of the Airport Core Programme projects for the new Chek Lap Kok Airport. Secured by Leighton Contractors (Asia) Ltd in early-1992, the work commenced in May of the same year, with completion and handover to the Hong Kong Government in May 1995.

Jan 1, 1995

This paper reviews the geochemistry of weathered nickeliferous sulphidic and lateritic profiles, the supergene behaviour of nickel and ore-associated elements, and their implications for exploration in an attempt to distinguish between barren and mineralised nickeliferous profiles. Nickel is an abundant accessory element in ultramafic rocks with background concentrations in some units up to 0.25 weight per cent. Ore-grades in fresh rock are mostly associated with massive and disseminated sulphide zones within magnesium-rich layered ultramafic sequences. In lateritic weathered terrain, nickel is also concentrated in the regolith profile. This process not only upgrades nickel in the gossanous weathered product of sulphidic deposits, but for sub-economic sulphide zones and some ultramafic rocks, is sufficient to result in a supergene resource. Ore-grade accumulations of nickel in regolith after sulphide-poor ultramafic rocks are referred to as lateritic deposits. Nickel sulphide zones and their ferruginous weathering products are collectively referred to as sulphidic deposits and are the major source of nickel in Western Australia. Mineral exploration in the Yilgam Block is hampered by deep lateritic weathered profiles (eg Butt and Sheppy, 1975; Smith, 1977; 1982). During the nickel boom of 1967 - 1972, most discoveries resulted from the location of outcropping nickeliferous gossan and ironstone. Exposed ultramafic terrain with nickel sulphide potential were explored intensively, mostly by gossan and soil sampling. However, up to 85 per cent of the area of the Yilgarn Block is buried by transported regolith. In these covered areas, barren and mineralised rock responses at the surface are similar and soil sampling produced unreliable results due to many false anomalies. A statistical, multi-element approach to regional geochemical exploration has evolved. Potential trace element indicators investigated, include Co, Cr, Cu, Ir, Mn, Pb, Pd, Pt, Sc, Se, and Zn. In recent years, trace element ratios have also been tested with varying degrees of Success.

Jan 1, 1996

By C V. Deutsch

"Geometallurgical variables often cause problems to conventional geostatistical workflows. There are many variables; some are compositional and some are non-additive. They often show: complex multivariate relationships undersampling relative to conventional grade variables unequal sampling; that is, all variables are not available at all data locations.A variety of approaches have been developed over the years, but geostatisticians remain mostly focused on modelling rock types and a few grade variables with an abundance of data. The problems are reviewed and a chained workflow is presented where appropriate techniques are employed in sequence to permit reliable spatial prediction of geometallurgical variables. The spatial models may be used to assess the value of additional data, for prediction of process performance, for improved mine planning and other optimisation tasks. The chained workflow will include data transformations such as ratios and normal scores that make the variables amenable to geostatistical modelling. Data imputation techniques to account for missing values are considered with special consideration to spatial correlation with the available data. Decorrelation techniques such as the principal components, min/max autocorrelation factors and projection pursuit multivariate transformation are employed to manage massively multivariate modelling. Full distribution modelling must be considered to avoid biases in the prediction of non-additive variables. The post-processing of geometallurgical models must be streamlined for robustness and efficiency. The precise workflow varies according to the specific purpose of the study. Guidelines and thoughts on best practice are presented.CITATION:Deutsch, C V, 2013. Geostatistical modelling of geometallurgical variables - problems and solutions, in Proceedings The Second AusIMM International Geometallurgy Conference (GeoMet) 2013, pp 7-16 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 29, 2013

By G Varley

This paper describes the mining methods and strategy used to extract the 5 Orebody crown pillar at the Isa Lead Mine over the past five years. The bulk of the crown pillar was extracted by the use of sublevel open stope method. An uphole bench stope was mined to scavenge the remaining ore. Geomechanical issues associated with the crown pillar extraction are described. Stope sizes were gradually increased on a stope by stope basis. This has allowed the maximising of ore recovery while relevant risks were managed. The principles in designing ore rib pillars against various types of fill materials are also described.

Jan 1, 2002

pNumerical modelling has been used to examine the relationship between the results of two commonly used methods of assessing the propensity of coal to spontaneous combustion, the R70 and Relative Ignition Temperature tests, and the likely behaviour in situ. The criticality of various parameters has been examined and a method of utilising critical self-heating parameters has been developed. This study shows that on their own, the laboratory test results do not provide a reliable guide to in situ behaviour but can be used in combination to considerably increase the ability to predict spontaneous combustion behaviour./p

Jan 1, 2005

By Cloutier JY, Quinn P, LeClerc A, Dube G, Agar GE

Gold dissolution by cyanide requires the presence of oxygen which is usually supplied by sparging compressed air into the gold containing slurry. For those ores that contain certain obnoxious substances that consume oxygen, maintaining the required minimum level of dissolved oxygen can be troublesome. One of the most economical solutions to the problem of low dissolved oxygen, especially in plants that have air compressors installed, is to enhance the rate of oxygen mass transfer. The oxygen mass transfer rate was measured in a two phase system using two different sparger arrangements, and with addition of a frother that is known to reduce the bubble size produced by the sparger. The common sparger system was shown to be inefficient compared with a readily available but under utilised method of gas dispersion which introduces air directly below the reactor turbine. Transfer of this technology to an operating plant confirmed the beneficial effect of the improved sparger system. The addition of the frother did decrease the bubble size, but it also reduced the oxygen mass transfer rate.

Jan 1, 1993

By T G. Measham, D A. Fleming

When attempting to understand potential regional or community socio-economic changes that resource-extraction industries may produce, it is important to analyse the channels that promote these changes. In this study, we propose a conceptual framework to better understand how socio-economic effects are likely to emerge in regions impacted by mining. The framework considers three levels of hierarchical effects (Measham, Fleming and Schandl, 2016).In the first level, the resource-extraction industry causes four direct initial impacts on nearby communities: labour demand shock (mining employment generation), income generation (compensation to landowners and higher wages), environmental consequences and land tenure/Aboriginal issues and an increase in local tax revenues.The second level is shaped by the subsequent population increase (given by immigration of permanent or temporary residents) produced by the new levels of employment and income that resource windfalls can generate in resource-extraction regions. These increases in employment, income and population become the source for a rise in the demand for local (and non-local) goods and services.Finally, the third level is given by boomtown-like and other socio-economic effects generated from the initial effects.CITATION:Measham, T G and Fleming, D A, 2016. A conceptual framework to understand the local community/social impacts of mining, in Proceedings Life-of-Mine 2016 Conference , pp 188–190 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By B Snook, G Rollinson, R Fairhurst, R Herrington

Nickel laterites constitute a significant proportion of the worldÆs Ni reserves and are considered environmentally friendly alternatives to traditional sulfide resources. Subsequently they are of increasing significance for exploration and production. To be successfully exploited, however, they require an understanding of the relations between mineralogy, texture, grade and recovery. The development of automated quantitative mineralogy can aid in the characterisation of the ores to help improve extraction and processing methods. Recent developments in hydrometallurgy have resulted in relatively straightforward recovery of Ni in silicate (saprolite and smectite) ores. However, the extraction of Ni from limonitic ores is more complex. It requires a detailed understanding of the iron-hydroxide species and other, potentially interfering, oxide and hydroxide compounds. Particularly the relations between the Ni-bearing goethite and Mn, Al and Cr may adversely affect the economic prospects of an ore. Manganese can adversely affect the selective recovery of Ni and Co from solutions but has also been highlighted as a significant potential by-product (cf, Zhang and Cheng, 2007). Aluminium hydroxides can be significant acid consumers leading to an increased expense of extraction (Johnson, Cashmore and Hockridge, 2005). Chromite is resistant to acid attack, but chromium in goethite may adversely affect the dissolution leading to a retention of Ni (McDonald and Whittington, 2008). This study presents an investigation of oxide and hydroxide species in laterites using QEMSCAN« EDS/SEM-based automated quantitative mineralogy. Samples were collected from Turkey (¦aldag), Albania and the Philippines. Particular emphasis has been placed on the development of a quantification for Ni-poor and Ni-rich goethite.

Jan 1, 2008

The classical view of island arc geology is that of a plutonic intrusive/volcanic extrusive complex, derived from the products of oceanic lithosphere subdu.ction and constructed on an over-riding plate of oceanic origin. Such an arc is typically backed by a marginal basin, formed by seafloor spreading of a more or less conventional kind. Various studies undertaken over the last decade have modified this picture and provided a new tectonic framework within which to explore for resources. Formation of Marginal Basins During the 1970s, seafloor spreading magnetic anomalies were identified in various marginal basins in the SW Pacific. In one of these, the South Fiji Basin, there was clear evidence of a ridge-ridge-ridge triple junction, although no kinematic relationship to the major plate boundaries was determined. Palaeomagnetic studies conducted in Vanuatu and Fiji, and in the Bismarck Archipelago of PNG provided evidence of large scale arc rotations relative to major plates. This indicated a general pattern of marginal basin formation by ridge-ridge-ridge triple junction growth together with island arc growth by trench-ridge-trench triple junction evolution. Formation of Primitive Island Arcs The triple junction growth model strongly suggests that at least a significant amount of arc evolution occurs by the initiation of subduction at a spreading ridge. This has predictive implications for the nature of island arc basement.

Jan 1, 1987

By J Pan, T Chun, D Zhu, Z Guo, J M. Young, T C. Ooi

With the rapid development of the Chinese steel industry, the strong demand for iron ores has led to huge imports of various iron ores from all over the world. As a relatively new force in the iron ore world and an important raw material supplier, Fortescue Metals Group (FMG) has achieved an annualised production rate of 100 Mt of iron ore fines. Typical blends were designed to simulate sinter blends employed in Chinese steel mills, and to determine sintering properties and metallurgical performance of blends comprising FMG Rocket fines in pilot sinter pot. It is shown that the sinter of typical blends comprising 15 - 20 per cent rocket fines possesses excellent sintering properties and metallurgical performance. With Rocket fines substitution for competitor ores in a typical customer mill blend comprising fully imported fines, the sinter productivity and tumble index increased from 1.45 t/m2h and 62.0 per cent to 1.54 t/m2h and 64.0 per cent, respectively, while attaining similar reducibility index and reduction degradation index at lower solid fuel consumption.CITATION:Zhu, D, Guo, Z, Ooi, T C, Chun, T, Pan, J and Young, J M, 2013. Sintering and metallurgical performance of blends comprising Fortescue Metals Group rocket fines, in Proceedings Iron Ore 2013 , pp 519-524 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Clark T. M

Underground coal mining involves the disturbance of natural strata stresses formerly in equilibrium, the production of noxious and flammable gases and dust which can be both an explosion and a health hazard. It involves also the use of heavy, large equipment operating on natural floors and in confined spaces. Such operations are required to be carried out under artificial light. Much of the easier won coal, that is the shallower coal, from this State has already been extracted and in future workings will be required to go deeper. As the depth increases strata pressures will increase, gas production is likely to be greater and the production of dust will also increase. A further problem which has not yet reached significant proportions in Australia is the potential rise in working temperature. This will be occasioned not only by the use of large items of equipment which themselves generate heat, but due also to thermal gradients as the depths increase. The need for better employee training is now being widely recognised throughout the industry. Under present highly mechanised conditions new employees should not be required to work with or near heavy mobile machinery without proper training

Jan 1, 1976

By D B, M A. Sares, D W. Coulter, D C. Peters

This presentation discusses NASA-funded research on the ability of hyperspectral remote sensing to map diagnostic acid rock drainage (ARD) mineralogy that adversely affects water quality within watershed and to determine the relative contributions of natural ARD sources of metals and acidity to that drainage. Ground-based reflectance spectroscopy, combined with water chemistry, is used to identify mineralogical and chemical variations throughout a watershed. Integrated with hyperspectral data acquired from airborne remote sensing platforms, such as the NASA Airborne Visible Infrared Imaging Spectrometer (AVIRIS) sensor, a methodology has been developed that should improve environmental assessments and tracking of impacts on and from drainages. Phase I of this project focuses on a drainage basin (Lake Creek), tributary to the upper Arkansas River in central Colorado, which is impacted by natural acid rock drainage from areas of high-sulfide hydrothermal alteration. This project builds upon research and inventory efforts by the Colorado Geological Survey (CGS) to identify hydrothermal alteration that is the primary source or is contributing to acidic and toxic drainage in Colorado. This presentation will cover ground and airborne hyperspectral remote sensing techniques and results and water analyses for seasonal high-flow and low-flow conditions in Lake Creek. Identifying correlations between mineralogy, especially mineralogy that can be identified through airborne remote sensing, and water chemistry is a key focus of this project. Of particular interest are low-pH iron phases such as jarosite, ferrihydrite, schwertmannite, copiapite, and transitional amorphous phases as well as AlOH phases from higher, although still acidic, pH environments which are observed to mix with the iron precipitates within the streams draining from the hydrothermal systems. Drainage in the Lake Creek watershed derives from the Grizzly Peak caldera (Oligocene), which exhibits extensive hydrothermal alteration. Alteration types include silicic, quartz-sericite, quartz-sericite-pyrite, advanced argillic, and argillic. By understanding the chemistry of a naturally impacted drainage and its relationship to the surrounding geology, the project goal is to allow more efficient and complete identification of such sources in mineralised terranes through remote sensing technology.

Jan 1, 2003

By P G Simpson

The Sundance gold mine, located 2.5 km east of the town of Batchelor in the Northern Territiory, has produced over 5300 oz of gold since it was discovered in 1978. Sundance is unique in the Pine Creek Inlier in that the ore is hosted in palaeo-karst detritus and crystalline magnesite of the Early Proterozoic Coomalie Dolomite. This paper presents a summary of the geology of the mine, and describes the methods used during the two periods of mining.

Jan 1, 1994