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The Boddington Gold Mine orebody is a large tonnage, low grade gold deposit located within the Archaean Saddleback greenstone belt within the south-western region of Western Australia. The orebody consists of laterite caprock (30 per cent) and clays (70 per cent) produced by lateritisation of felsic volcanics and intrusives. The caprock comprises gravel, hardcap and B-zone which have a specific gravity of 1.8, 2.4 and 1.8 respectively. The clay has a specific gravity of 1.5.

Jan 1, 1993

By P Thompson, D Rose, S Yu, W Baum, R Zahn, D Meadows, G Hall

Opportunities to improve mill operations are often cited by mining companies and recognised in many concentrators spread throughout the world but are not always followed through. Copper-molybdenum concentrator operations are challenged by a continuously increasing list of detrimental factors. They include deteriorating ore characteristics and poor mineralogical information on deeper ores, water quality and availability, steel wear and increasing power costs. Rapidly declining productivity, sustainability and environmental factors, new taxes, mining industry global skill set shortages, to name but a few, must also be considered. The days of maximising value by just increasing production or simple cost cutting are fading and will not be sufficient for the future of more complex mineral processing operations and larger plants. As a result, FLSmidth’s Global Process Technology Group has launched a plant and process optimisation program based on mineralogical and metallurgical surveys.Copper-molybdenum concentrators of the future need a paradigm shift. Modelling and simulation tools alone are not the answer to complex mineralogical associations and larger scale equipment and operations. Detailed area by area review aimed at identifying process constraints in terms of equipment and operating practice in conjunction with robust diagnostic work, ie mineralogical and metallurgical characterisation, are mandatory for process optimisation. The navigational beacon, for all operations who want to remain competitive, will be ‘process efficiency’. Since the use of automated mineral analysers has become more readily available and reliable, mineralogical-metallurgical plant surveys have proven themselves as the most efficient tool for optimising plant performance.The following paper will illustrate how operations can move toward eliminating under-performing flow sheets, fixing run-away flotation conditions, maximising individual process equipment performance, preventing shortcuts in Bond work index testing which may cause the failure of comminution models and minimising costly and time-consuming ‘debottlenecking’. As previous plant surveys have shown, the net project cash flow can be increased by 50 to 200 per cent if a combination of robust ore characterisation and plant process mineralogy is performed. The combined plant survey approach has been demonstrated successfully in a multitude of operations. This includes the use of key ore types in concert with statistically sampled process streams, bench-scale metallurgical tests and automated mineral analysis on a size-by-size basis.CITATION:Meadows, D, Hall, G, Rose, D, Thompson, P, Baum, W, Zahn, R and Yu, S, 2014. Copper-molybdenum concentrator surveys using mineralogy and process benchmarking tools to improve overall plant performance, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 315–322 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

Discontinuities often have a very detrimental effect on the stability of mine highwall faces. The west wall of the Muja open cut is remarkable for the number and variety of discontinuity sets which occur over a relatively small area. To-date 14 separate structural domains have been identified over an area measuring approximately 560 m by 120 m.The structural domains have been grouped into four structural assemblages on the basis of their angular relationships to each other and to regional folding and faulting. The distribution of these structural assemblages appears to be erratic and no controlling factors have been identified to explain or predict them other than in the most generalised terms.

Jan 1, 1993

Mineral deposits in New Zealand whose origin can be ascribed to primary magmatic segregations are associated with mafic-ultra- mafic complexes related to two orogenic episodes which took place during Paleozoic and Mesozoic times. These mafic-ultramafic complexes are essentially of two types. One is ophiolitic and has podiform chromite mineralisation presumably formed below a spreading ridge. The other type occurs as intraplate layered intrusions in which Fe-Cu-Ni sulphides and Fe- Ti-V oxides have formed as a result of liquid immiscibility with the host magma, and have subsequently accumulated by gravity means. Generalised descriptions are given for some deposits in NW Nelson, Fiordland and Marlborough districts.

Jan 1, 1980

By DiStefano AB, Dale SG

This paper describes the laboratory study implemented to investigate the application of the subaerial technique to tailings disposal for the proposed Olympic Dam Mine. The results of the study and the resulting design parameters are presented. The subaerial technique of tailings disposal is described and the advantages of the method for disposal in arid climates highlighted.

Jan 1, 1984

A review is given of progress made to- wards the development of personal gravimetric dust sampling for risk assessment on South African gold mines. The present strategy is critically examined on the basis of principles for assessing health hazard from dust exposure. Reasons are advanced for replacing the konimeter with a gravimetric system based on full shift personal sampling. Constraints imposed by local characteristics of gold mines are used to illustrate the difficulty in finding suitable instrumentation for measuring personal exposure to respirable silica.

Jan 1, 1988

By Schmidt CG

Parameters affecting gold elution using the AARL process are reviewed and critically analyzed in an attempt to optimise metallurgical efficiency and minimise costs in both current and future carbon adsorption operations. Such factors as acid washing, column geometry, elution temperatures and pretreatment reagents are discussed together with eluant water quality and eluate flowrates. Hot acid washing of carbon prior to gold elution has many benefits. Besides improving elution efficiency when eluting with regional water, a hot acid treatment preheats the carbon without causing any gold leakage. Laboratory data indicated that hot acid washing reduces the mass loss of carbon during thermal regeneration. The eluate going to either zinc precipitation or electrowinning is also relatively free of troublesome impurities (organic contaminants and ferrocyanides in particular). Because of the chromatographic character of the AARL elution where an ionic strength gradient is used to inhibit the readsorption of gold, column geometry plays a significant role. While practical considerations and capital costs may restrain the length of the elution column, high length/diameter ratios are advocated in order to promote the plug flow of column eluate. From both a metallurgical and costing viewpoint, the two significant factors affect- ing the AARL gold elution are temperature and cyanide addition. High temperature and high reagent additions within prescribed limits will improve metallurgical efficiencies, but a balance between energy and reagent costs is required in order to minimise overall elution costs. As pretreatment reagents constitute a considerable portion of the total elution costs, both the addition and consumption of sodium cyanide must be carefully considered. Lower cyanide additions may be effective in certain instances, but the more practical use of 0,6 bed volume of a 2-3 per cent NaCN reagent containing 2 per cent NaOH is advocated. This is equivalent to an addition of 20-30 kg NaCN and 20 kg NaOH per ton carbon Treated.

Jan 1, 1986

By Shunli Z, Jin X, Guanzhou Q

Flotation behaviour can be controlled, due to diminishment of granula quality and extension of specific surface area, by adding coarse particles (high- grade concentrates) to condition pulp. It has been substantiated that coarse particles can intensify fine particle flotation and its mechanisms are effects of carrier, intermedium and assistant aggregation of coarse particles. Calculation and analysis of Reynolds numbers and their variation for different size particles, under specific turbulent dynamic conditions, reveal that agglomeration among granulae is subject to specific turbulent dynamic conditions. Furthermore, sizes and adhesion strength of flocculated particles are the function of specific physical and chemical factors. Based on this research an innovative ramification carrier flotation process has been developed, which has been applied to Fankou Lead- Zinc Mine, Guang Dong province, China, etc, with satisfactory results. These results shed light on distinction between conventional flotation and fine particle flotation, meanwhile, provide a basic approach for further solution of fine particle flotation problem.

Jan 1, 1993

By Hamblyn S

Oakbridge, in combination with its joint venture partner, Nippon Steel of Japan, is expanding its Bulga underground and open cut mines to meet the growing demand for coal in the Asian market. Expansion works underway will see the Bulga underground mine become a world leader in underground productivity, the introduction of a high capacity dragline into the open cut mine (largest capacity dragline in NSW) as well as a major upgrade of the coal preparation plant (CPP) and coal handling facilities (CHF) to process the increased production. This paper describes the planning and implementation of this major expansion program and highlights the rationale behind some key aspects of the program.

Jan 1, 1995

By Manca PP, Rossi G, Lipari D, Knissel W, Massacci G, Licheri P, Fioravanti E, Helms W, Lai S

Mining of the massive complex sulphides orebodies of Campo Pisano and San Benedetto (Southern Sardinia, Italy), dates back to before Christ, though their exploitation with modern technology was only resumed in the middle of the last century. The increasingly adverse economic conditions and the weakness of both country rock and mineralization were concurrent in forcing the Company's management to develop suitable high-productivity stoping methods. In the framework of a project fi- nanced in part by the Commission of the European Coranunities, and carried out in cooperation with the Universities of Cagliari (Italy) and Clausthal (Germany), a cemented backfill stoping method was developed. The concrete mix preparation and placement facil- ities, study of the cement mixes and endeavaa-s to optimize the methods are described. The monitoring system for measuring stress evolution within the emplaced backfill is illustrated together with the successful replacement of part of the Portland cement

Jan 1, 1992

By Dight P. M

The challenge of narrow vein mining is to produce ore with as little dilution as possible, at the least cost -commensurate with the increasing degrees of safety being demanded for mine workers by the modem 'duty of care' legislation. Geotechnical factors play an important, if not overriding, role in these areas. The geotechnical factors cover the complex interaction over a period of time, between the in situ and induced rock stresses, rock structures, rock mass strength and the cable, rock bolt and other ground support members. In the Archaean schist belt areas where many of our narrow vein mines occur the pre-mining in situ rock stresses are commonly significantly higher than the overburden stresses. These are concentrated in areas beneath previous open pits and may be highly concentrated in the pillars and abutments of stopes on narrow veins. The presence of high in situ stresses may be suspected from the appearance of drill cores and underground development long before they become sufficiently concentrated by mining to cause damage or bursts. These initial indications are discussed and modem low cost methods of stress measurement are described. Practical and quick methods of analysing the stress redistribution around scopes and other underground excavations are now available and guidelines for interpreting them in terms of rockmass characteristics, stope stability and support requirements are developed with the object of increasing safety, whilst reducing overall costs and dilution.

Jan 1, 1993

By Martin T

High methane content of the medium volatile metallurgical coal mined from the Coal Basin mines causes very difficult mining conditions. Rapid desorption into the mine ventilation system limits coal production, requires huge fresh air quantities and creates mine safety problems. In workings deeper than 2000 ft (600m) gassy coal and heavy cover create outbursting conditions. Cross-measure methane drainage has reduced ventilation requirements on advancing faces, but degasifica- tion of virgin coal is needed to improve mining Conditions.

Jan 1, 1982

By E Kasai, D Maruoka, Y Konno, T Murakami

The iron ore sintering process produces approximately three per cent of carbon dioxide emission in Japan because a large amount of coke breeze is used as the main agglomeration agent. Therefore, its suppression has been required. A promising method is to replace the coke breeze with biomass char and iron-bearing materials. In this study, the effect of the utilisation of metallic iron with coke or palm kernel shell char (PKS char) as an agglomeration agent on its oxidation behaviour was examined by a series of experiments using a sintering simulator. The use of PKS char leads to a larger decrease in the pressure drop difference of the sintering bed compared to the case using coke. Furthermore, the oxidation rate of metallic iron was larger in the case using PKS char together than that using coke. It was considered that the oxidation of metallic iron was promoted because the bed-temperature increased at a faster rate and achieved a higher temperature.

Nov 8, 2021

By E L. Kotova

Completeness of extraction of a mineral from ore depends on many reasons. First of all it is a function of quality of disintegration of ore. It is supposed that two basic factors: character of structure and texture of the ore aggregate and a disintegration technique influence the quality of the mineral aggregate destruction, æopeningÆ of its internal boundaries. In this paper, the problem of technological mineralogy from the point of view of genesis of the mineral aggregate, its typomorphical features and methods of their quantitative description are discussed. The purpose of this research is to provide information for technologists. It should enable the development of a rational flexible scheme of disintegration of ore with full extraction of a useful component, without its losses and without unnecessary expenses of energy. For achievement of this purpose the mineralogical information should have ½number and a measure+. By the authors, the technique of the quantitative analysis of fabric of the mineral aggregate based on several models û thermodynamic, crystallographic and geometrical is offered and discussed. The leading role in the quantitative analysis of a fabric of ore belongs to internal bounders. But internal bounders of the mineral aggregate by bounders or faces of the mineral individuals or mineral grains are formed. Their geometry, orientation concerning own (mineral grain) crystallographic lattices, orientation and distribution in space of the ore aggregate are proportional to the energy accumulated at origin and the further growth. These characteristics of mineral individuals are consequences of conditions of their formation. That is why the named triad of models is used. From crystallography it is known that faces of different stability and mobility form borders of crystals. They also contain different quantity of energy. Mineral grains also are faceted by different energy borders. They form intergrowths with each other according to a principle of balance or unbalance. That is why in addition to traditional parameters of the description of a fabric of the mineral aggregate (mode and grainmetrical composition) it is necessary to add new. For example, length and the square of intergrowthing bounders of mineral individuals differentiated (in couples), crystallographic symbols of borders, their roughness and so forth. Consequently, solving a problem of the geometrical characteristic of borders, we define also its power characteristic. In this paper experience of application of our technology in studying ores of one of deposits of Urals Mountains is presented. For realisation of these types of the analysis technologies of measurement, the program of calculation and the devices, which are carrying out the analysis in a semi-automatic mode, are possessed. Structure and texture of rock or ore aggregate reflect its formation and transformation conditions. It is important to understand that disintegration energy cannot be more than aggregation energy, the energy of intergrowths formation. The square and orientation of mineral individuals borders vary at pressures or stresses of mineral aggregate evolution. These phenomena often cause selective increase in the square of borders at constant average grain size, ie the granulation. Granulation presents the increase in quantity of mineral individuals while their modal share remains constant. At the same time their average mineral grains size. Some mineral individuals increase in size at increased pressure. When lithostatic or lateral pressure drops the majority of mineral grains increases in volume at the cost of intersticial or film solutions or fine grains. These are only special examples of the ontogenesis of the mineral aggregate. They illustrate our statement that all changes in fabric of the mineral aggregate are a reaction on varying external (ie geological) conditions. It is possible to consider that structurisation of totality of mineral individuals as a whole is a process of adaptation of the mineral aggregate, which forms and exists in varying force and energy fields. Differential and integrated geometry of total internal boundaries of the mineral aggregate serves as adaptation mechanism of the mineral grains system. Boundaries form intergrowths of the mineral aggregate. Thus, it is possible to consider that the most informative parameters of the stereometric analysis for restoration of the ontogenesis of the mineral aggregate are the following. First of all, it is a quantitative estimation of the volumetric shape of the ore mineral in crystallographic coordinates, a total area of borders of all mineral grains in the aggregate, the specific square of their boundaries, the specific square of intergrowth boundaries of the ore mineral separately with grains of each minerals of the matrix of the mineral aggregate as well as traditional grainsmetric and modal composition. For realisation of these types of the analysis technologies of measurement, the program of calculation and the devices that are carrying out the analysis in a semi-automatic mode are possessed.

Jan 1, 2008

The outlook for suppliers of energy to the expanding economies of the Pacific Basin region is essentially positive, but particularly for exporters of high quality steam coal. This paper argues that economic growth in the Pacific Basin region has exceeded world economic growth for some years and that this will continue to be the case for the next decade at least. It looks briefly at the link between economic growth and energy demand and at the relationship between energy demand and the demand for electricity.Changing preferences in fuel mix for electrical generation in the region are noted and tentative forecasts made about variations in this mix. The pros and cons of various forms of fuel used to generate electricity are considered from the point of view of the consumer.

Jan 1, 1990

By Merry N, Cocks T

The mineral exploration industry is increasingly aware of the importance of the relationship between mineralogical data and geochemical assay results. However, until recently, the cost and time constraints of most techniques for analysing alteration mineralogy have precluded detailed alteration studies. These impediments have been reduced by the development of the Portable Infrared Mineral Analyser (PIMA), a field portable infrared spectrometer that allows rapid (in field) and cost effective analysis of alteration minerals including subtle variations in mineral crystallinity and Composition.

Jan 1, 1995

By R N. Humphries, R J. K Thompson

Large-scale coal mining in South Wales dates back to the late 18th and early 19th centuries with the birth of ironmaking on an industrial scale. This rapidly gave rise to new and large communities with immigration from far and wide across the United Kingdom (UK). These new communities were largely dependent on coal mining and served as the main form of employment and social cohesion until the industry’s demise in the 1990s. With wholesale mine closure and the concomitant loss of employment, the extensive environmental degradation and chronic mine-related illness left a deep scar on the psyche on many still living in the South Wales mining communities. This coupled with memories of strife in the 1980s has resulted in ongoing hostility toward the surface coal mining of the remaining accessible coal reserves in the proximity of these communities.The purpose of this paper is to set out the historical basis of the concerns of these legacy mining communities in South Wales and explain how they are being positively addressed by both the recently evolved planning and regulation system and by today’s surface mining industry. Reference is made to experience gained from two recent applications for surface coal mining adjacent to former mining communities. Ways are suggested in the approval process that surface mining can work in more harmony with the local communities through working partnerships between the mining company, the authorities and regulators and the affected communities. It is concluded that partnership is key to creating a more responsive mine-operating culture and a means to securing approval for future surface coal-mining prospects in South Wales, and probably elsewhere too.CITATION:Humphries, R N and Thompson, R J K, 2014. Surface mining and legacy mining communities in South Wales, UK, in Proceedings Life-of-Mine 2014 , pp 399–412 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By Stevenson I, Dickinson W, Taylor R. N

Despite flash smelting's widespread use little is known about the actual processes taking place in flash furnace shafts and comparatively few reports of sampling campaigns have appeared in the published literature. his paper reviews the previous reports of the use of horizontal trough samplers and analyses their expected collection efficiency. In the light of the deficiencies revealed by this analysis an isokinetic sampler was produced and a vertical sampling technique was also developed to obtain samples from directly below the burners in the shaft of the flash furnace at the Kalgoorlie nickel smelter. Comparison of the sizing of the samples obtained with the horizontal trough and isokinetic samplers confirmed the theoretical analyses and showed that the trough samplers were not collecting the fine particles. Besides providing data to validate mathematical models of the burners and shaft, chemical analyses of the shaft samples showed that the coal in the charge was reacting preferentially and that the plume of at least one of the burners was being deflected from its axial position. In the region directly below the burner there was evidence that the disperser on the burner was imparting more momentum to the coarser particles and that these were concentrating in the outer regions of the particle plumes issuing from the burners.

Jan 1, 1992

By Cocker J, Urosevic M

Seismic methods have become common for the detection of low-throw faults ahead of underground coal mining. Surface seismic methods cannot theoretically be used where dykes occur, because seismic waves transmit from the surface down to the seams, and reflect back to the surface. Consequently, where sub-vertical structure such as dykes occurs, the surface seismic method fails.The ability of seismic methods to image dykes depends on the geometry used, the dyke thickness and the seismic wave propagation mode in relation to dyke composition and internal structure. Surface seismic methods find it difficult to distinguish between faults/fractures and very thin dykes (1-2m in thickness) when the dyke's thickness is less than the seismic wavelength. Consequently, borehole seismic methods have to be used to detect the presence of such thin dykes.

Jan 1, 1998

By J Player, G Sweby, S Webber, E Jones

Seismic systems are a tool for the monitoring and forecasting the rock mass response to excavation. Common issues encountered at mine site audits and reviews are: how to design an effective seismic system, implementation of the design, interpretation of seismic source results and understanding the reliability of the seismic source. These issues are often a function of several items including: • Experience of site personnel in undertaking seismic system design. • Personnel not envisioning multiple phases of system expansion to understand system robustness issues. • System design/expansion occurring in response to damaging seismic activity rather than planned expansion of a system • The mine access development is often localised in comparison to the total orebody being mined hence, planning sensors in longholes in advance of development rather than in short holes close to development will improve the three-dimensional aspect of the network. • Limited site processing of the seismic event data, hence engineers do not see the uncertainty associated with event location, size, source and system layout. Mine site users require a framework to appreciate the challenges and limitations in locating large events. For example, event locations are given as precise measurements (to the nearest centimetre) whereas the volume of deformation resulting in the event often has dimensions of tens of metres or more (as defined by the source radius). A stronger awareness of the uncertainty of rock mass yield within large seismic sources will assist site users in the interpretation of rock mass damage. The encountered design and implementation errors are reviewed and discussed with a practical set of rules presented to provide a robust seismic system that provides consistent results and increases the user’s understanding of uncertainty in source location and size. The authors’ experience across multiple mine sites, seismic systems and damaging seismic events over a 30 year period has been summarised into practical rules for site personnel of all experience levels.

Nov 29, 2022