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By Oboso A, Nakahiro Y, Takenaka Y, Wakamatsu T

As part of the fundamental studies on the recovery of Au by solvent extraction, the synergism of combined extractants on the extraction of An from the sulphuric acid solution containing thiourea was investigated. Extractants tested were di-(2-ethylhexyl)phosphoric acid (D2EHPA), tri-n-octylamine (TOA), tri-n-butyl phosphate (TBP), and trioctyl phosphine oxide (TOPO). Four kinds of extractant combinations, D2EHPA/TBP, D2EHPA/TOPO, TOA/I'BP, and TOAITOPO, were tested to clarify the synergism on the extraction of Au in terms of various concentration ratios, diluents, the concentration of sulphuric acid, and the concentration of thiourea.

Jan 1, 1993

By T A. Short, P L. Brown

Kestrel Mine co-disposes around 1.5 Mt of fine (2SO4/t and to date around 9 Mt has been deposited. The mine plans to co-dispose of approximately 39 Mt of material, creating a dump with a maximum height of 35 m and a disturbance footprint of 260 ha. Benign materials suitable for rehabilitation are severely limited and no successful rehabilitation strategy has yet been demonstrated. A rigorous measurement and modelling program is resolving outstanding issues associated with acid rock drainage (ARD). The objective of the program is to develop and validate a strategy for dump rehabilitation that will control ARD and allow for mine closure. The strategy includes using a soil cover to reduce water flux into the dump to control the overall oxidation rate and to control effluent release. Monitoring of the oxygen distribution and water flux in the uncovered material commenced in February 2001 and monitoring in waste under a trial cover commenced in February 2002. Carbonaceous and sulfidic oxidation rates have been measured. Initial modelling indicates that the carbonaceous material has the general effect of slowing the rate of pyrite oxidation, lowering the maximum sulfate production rate and extending the time to oxidise all the sulfides. The combined approach of measurement and modelling provides a sound basis for assessing the performance of the trial cover and predicting the long-term quality and quantity of effluent at the base of the rehabilitated waste dump.

Jan 1, 2003

Underground excavations are subjected to complex stress changes caused by nearby mining, but may also be affected by repeated dynamic loading from blasting and seismic events. In some cases, the combined, cumulative effects can lead to unforeseen damage, displacement and instability. Simulating dynamic loading of an underground excavation is a very complex task. The state of rock mass stress, damage and deformation must first be simulated sufficiently requiring small-scale structures to be explicitly modelled. Supporting elements must be represented with high similitude and then the dynamic event must be applied to the system in the case of blasts, or evolve as a consequence of rock mass instability for seismic events. A special case is for the effect of pit blasting on underground excavations - discontinuous rock phenomena at scales from mine, to bench, to pillar, to tunnel need to be captured and this represents one of the most computationally intensive tasks in mine simulation. Recent advances in computer power allow these tasks to be completed at a mine scale, incorporating discontinuities and geological detail matching the best practice for static Finite Element analyses. The results are a worthwhile contribution to mine decision-making, but require careful interpretation and thoughtful inputs - even more so than quasi-static analysis - as the cumulative effects of unfavourable modeling practices are greater. Some learnings from experiences with mine scale, discontinuum dynamic simulation are summarised, including a discussion of considerations of scale and similitude for this type of analysis.

Nov 25, 2010

By Napitupulu P

PT Freeport Indonesia currently operates a concentrating complex capable of milling 127 000 metric tonnes per day of copper and gold hearing ore. The facilities consist of both a conventional crushing, ball mill and flotation circuit and a SAG, ball mi

Jan 1, 1997

Rather like the mythical "Economic Man" "an employer" in this context must necessarily be an abstraction, and the views possessed by such an abstraction, a composite of many views known to have been expressed. Not even the complex Conciliation and Arbitration legislation in this country provides any helpful specifications, except in one peculiar particular. The Australian Conciliation and Arbitration Act provides an almost totally tautological definition, except in that one oddity referred to above. It is this : "An employer means any employer in any industry, and includes any person who is usually an employer in an industry, and also includes a Club." No doubt there is some perfectly justifiable reason for such specific and unique particularity in an otherwise meaning- less definition. That need not trouble us in this exercise.

Jan 1, 1982

By E Ben-Awuah

Mine planning is the backbone of all mining enterprises and determines the profitability or otherwise of any mining investment. Providing high quality ore and tailings containment at the right time are the main drivers in oil sands mining. Recent environmental and regulatory requirements also makes waste management an integral part of mine planning in the oil sands industry (Directive 074). Due to the limitation of lease area, the pit phase advancement in oil sands mining is carried out simultaneously with the construction of tailings dykes in the mined out areas of the pit. These in-pit dykes are constructed to hold tailings that are produced during the processing of the oil sands ore after an initial external tailings facility. Most of the materials used in constructing these in-pit and ex-pit dykes come from the oil sands mining operation, making it necessary to have a plan for supplying the dyke material. The research problem here is categorised as: determining the order of extraction of ore, dyke material and waste to be removed from a predefined ultimate pit limit over the mine life that maximises the net present value of the operation û a strategic schedule; anddetermining the destination of dyke material that minimises construction cost depending on the construction requirements of the various dykes as per their designs û an operational schedule. There has been developed, implemented and verified a theoretical optimisation framework based on mixed integer goal programming (MIGP) to address the oil sands long-term production scheduling and waste management problem. The research introduced the development of multiple material types and multiple destination optimisation techniques using MIGP in the context of mine planning. This study presents an integration of mixed integer programming and goal programming in solving large-scale mine planning optimisation problems using clustering and pushback techniques.

Sep 26, 2011

By P Crorkan

Within the framework in which future exploitations for Codelco-Chile Divisi=n El Teniente are situated, regarding the deepening of its reserves and the geotechnical problems that affect their recovery, it becomes strategic to evolve with new variants, which make deep mining possible. Codelco ChileÆs Divisi=n El Teniente is progressing within its long-term planning the exploitation of a sector called Esmeralda, which includes its removal through the gravitational caving method (panel caving). It is planned to use pre-caving, which basically consists of developing and undermining the undercut level, without having developed the infrastructure of the production and transport levels. This is carried out in order to achieve a better redistribution of the stresses, thus obtaining higher quality in the infrastructure development of these levels as well as less risk. The extraction reserves for this area, estimated through the opportunity cost selection criteria, were determined at 348 million tons with an average grade of 1.014 per cent Cu. The project carried out geological and geotechnical studies in order to prevent the geomechanical risks of the sector to be exploited, which is a site conformed totally by primary ore. Lithologically, it occurs mainly in Andesite, located at the western limit by Brecha Braden Pipe. There are also varieties of porphyries and hydrothermal breaches of anhydrite. The Esmeralda Mine production program will increase from 4000 tpd (average) in 1998 to its 45 000 tpd rate of production estimated for the year 2005. The approved investment for the period 1995 to 1999 is $US 150 million, out of a total $US 213 million for the project. At feasibility study level and before the project, it showed a Net Present Value of $US 342 million, an Internal Rate of Return of 37 per cent and an IVAN indicator of 2.3 for a ten per cent discount rate and a copper price of 100 US cents/lb.

Jan 1, 2000

By I Jabou, D G. Blazak, L C. S Hogarth

The R70 test is a good indicator of coal reactivity to oxygen and is commonly used to provide a rating of propensity for self-heating. Tests performed by The University of Queensland Spontaneous Combustion Testing Laboratory have resulted in the development of a large database that shows the impact of coal quality on this parameter. From these results it is possible to infer an R70 value, which can be used to gain an appreciation of the intrinsic coal reactivity before it is even tested. However, any interpretation of R70 values must consider the influences of coal rank, mineral matter and moisture content to provide a better understanding of the spontaneous combustion risk of a particular coal.

Jan 1, 2005

By L C. P J Fonteneau, B Godel, E R. Ramanaidou

The Hamersley Province in Western Australia hosts large iron ore deposits. Each deposit displays various iron ore types that were defined on their metallurgical properties, especially in terms of porosity and mineralogy. Conventional porosity and mineralogy information on iron ore types are provided on 2D thin sections using automated image analysis with scanning electron microscopy (SEM)-based techniques combined with chemical analyses. However these techniques cannot accurately quantify the 3D porosity. High-resolution X-ray computed tomography (HRXCT) is a non-destructive technique providing a 3D image of the sample with a resolution close to 0.5 - 0.7 ¦m for samples size of up to few centimetres in length. 3D image analysis using customised algorithms now provide accurate quantitative porosity and mineralogy of iron ore types.CITATION:Fonteneau, L C P J, Godel, B and Ramanaidou, E R, 2013. Application of high-resolution x-ray computed tomography to iron ore characterisation, in Proceedings Iron Ore 2013 , pp 243-250 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By N Kojola, A Vickerfält, J Huss

The possibility of using an acidic autogenous hydrogen direct reduced iron (H-DRI) slag as a basis for vanadium extraction is investigated. For a raw material to be suitable for producing high-quality FeV, the vanadium oxide content should be sufficiently high and the phosphorus oxide content in a tolerable range. Therefore, the feasibility for vanadium extraction relies on fulfilling two demands: the predominate partitioning of phosphorus to the metal and vanadium to the slag. Correspondingly, the behaviours of phosphorus and vanadium in the Al2O3-SiO2-FeOx-VyOz-P2O5-Fe system were studied experimentally. Slag, 10 g, was put in contact with liquid iron, 30 g, for different durations (2–24 hrs) in closed alumina crucibles at 1873 K. The slag composition was varied between 33.1– 49.3 wt per cent Al2O3, 27.1–46.7 wt per cent SiO2, 16.6–30.1 wt per cent FeOx, and 2.5– 8.8 wt per cent V2O3. The equilibrium phosphorus distribution was 0.42, while the vanadium distribution ranged from 7.6 to 43.4, increasing with the Al2O3- and the FeOx-content.

Jun 19, 2024

By L M. Zhang, X Y. Li

Surface displacements are routinely monitored at multiple points during slope excavation. The monitoring data reveals the safety status of the slope under current loading conditions. They can be used to enhance the prediction of the future performance of the slope by reducing the uncertainties of the prediction model and its model parameters. In a multistage excavation, the observed displacements in the current stage can be used to update the prediction of the displacements in subsequent stages. Besides, due to the spatial correlation of the slope parameters, the prediction of the displacement at one location can also be updated using the monitored displacements at adjacent locations. This study aims to develop a multistep updating method to enhance the prediction of the future performance of the slope using time-series monitoring data at multiple points. This method integrates the theoretical computational model with observational evidence. It considers the inherent uncertainty of the slope, model uncertainty and measurement uncertainty. With more monitoring information being incorporated, the prediction becomes closer to the actual performance of the slope. A case study of a multistage excavation of an extremely high rock slope in south-west China is presented for illustration.CITATION:Li, X Y and Zhang, L M, 2014. Better prediction of performance of a slope using time-series monitoring data at multiple points in a multistep excavation, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 183–188 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By G Le Juge, K Waldock

The current suite of bulk mining explosives has been available to the industry for over 20 years. The flexibility and performance of ammonium nitrate based emulsion blend explosives were accepted by the mining industry in the early 1980s. These water resistant explosives rapidly displaced the water gels and slurries developed during the previous two decades. However, since the 1980s there has been no equivalent step change to the basic formulation or application of bulk explosives, although there has been a continuous process of refinement with respect to stability, handling characteristics and most significantly, cost. In the 1980s explosives supply contracts were awarded based on technical evaluations, usually accompanied by field trials. Technical personnel from both mining companies and explosives suppliers dominated the negotiations and there was a strong focus on explosive energy and blasting requirements. Today, explosives from alternative suppliers are difficult to differentiate on the basis of energy so the focus has shifted to aspects of service and price û bulk mining explosives are now largely treated as a commodity and the negotiations are dominated by commercial personnel. Commercial pressures from large mining companies have seen a substantial reduction in the real price of explosives. However, this has come at a cost. In order to reduce manufacturing costs, emulsion formulations have changed. In general they are not only cheaper, but also less energetic. Powder factors have had to increase to achieve the same blasting results, especially in hard ground. It is debatable whether the mining companies have achieved all of the economies they were seeking. This paper discusses these issues and argues that the mining industry would benefit from taking a more technically driven approach to meeting their blasting requirements. Recent trends towards more open contracts between the mining companies and their suppliers can be extended to explosives. To achieve this, mining companies will need to acquire sufficient technical knowledge to take a more pro-active approach to specify the characteristics of the explosives required to maximise the economic performance of their operations.

Jan 1, 2004

The New Broken Hill Consolidated Airshaft is the first major undertaking in the development of New Broken Hill Consolidated Ltd's. property, which adjoins that of The Zinc Corporation Ltd. on the latter's southern boundary.The Zinc Corporation ore-body has a southerly pitch. The Zinc Corporation's New Main Shaft is 1000 ft. north of the common boundary, and the general plan of development of the New Broken Hill Consolidated property is by driving south from this shaft on the lower levels. No downcast airway from the surface was available south of the Zinc Corporation's New Main Shaft; this shaft acts as the main downcast to the bottom of the Zinc Corporation mine, the general air flow then being northward and upward to the upcast shaft at the extreme north end of the Zinc Corporation property.Rock temperature is 920 F. at 2000 ft., increasing by 10 Fahr. each 72 ft., the rock temperature at 3000 ft. being estimated at 1060 Fahr. With the general air flow northward from the Zinc Corporation's New Main Shaft, adequate ventilation under these temperature conditions would not be practicable for any great distance south of this shaft without another main airway from the surface. Accordingly the New Broken Hill Consolidated Airshaft is being sunk at a point 1000 ft. south of the common boundary, i.e., 2000 ft. south of the Zinc Corporation's New Main Shaft, to ventilate future New Broken Hill Consolidated workings and that part of the Zinc Corporation mine between the boundary and the New Main Shaft.

Jan 1, 1940

This paper attempts to draw together the experience of over 30 years of research and practice in the United Kingdom on the rehabilitation of abandoned metalliferous mining wastes. The reliance on water when the mines were operating has implications for water quality and the techniques used to restore sites to alleviate the principal impacts of the mines. Drivers of reclamation included concerns about human health from wind blown dust and pollution of watercourses as well as perceptions of dereliction. Techniques of reclamation used involved removal of spoil from near to surface watercourses, capping of spoil, diversion of watercourses, use of impermeable membranes, prevention of surface sinks into underground workings and the use of constructed wetlands. The issues to be dealt with in mine reclamation have become more complex and sometimes diverge. The schemes in the 1990s described have been effective in dealing with pollution from spoil heaps and small but significant adit discharges; however, significant issues, particularly those of large flows of polluted water from mine sites, still need to be dealt with. Although the paper describes the legacy of mining, which largely finished in the late 19th/early 20th century, similar issues but on a larger scale are to be found in more recent mining, for example Eastern Europe. In many of these areas minerals still remain to be won and dealing with this legacy may fall on new mining developments.

Jan 1, 2006

Just as geophysics, in the form of 3D seismic and wireline logging, plays a key role in petroleum reservoir management, so too will geophysics play an important role in mining of coal, metals, and minerals in the 21 st century. The commercial and social imperatives driving greater use of geophysics are reduced costs, increased revenues, and enhanced safety. In short, superior utilisation of capital and management of risks. In relatively undeformed sedimentary environments it is possible to adapt petroleum-style 3D reflection seismic to image mines. This has been demonstrated most impressively in the Witwatersrand. Anglo-American, for example, completed a $1 million 3D seismic survey at Western Deeps in order to site a new $300 million shaft with confidence. Likewise, 3D seismic has gained rapid acceptance at Australian coal mines in recent years. Encouraged by these successes, metalliferous mining companies are supporting research in Canada and Australia, as well as South Africa, to adapt 3D seismic for more highly structured, metamorphic terranes. Because the mining industry is far more diverse than the petroleum industry in terms of commodities and geological environments, 3D seismic is not always cost-effective. A plethora of other geophysical techniques can be applied, many of which are employed in mineral exploration. Mine applications of geophysics differ from traditional exploration applications in two main ways: time scales and length scales are shorter, and boreholes are more plentiful. Borehole geophysical techniques therefore play a more significant role, both for logging and imaging. Logging systems detail the variations of in situ physical properties down the borehole at scales measured in centimetres, while geophysical imaging techniques can map features located tens or even hundreds of metres from the sensors. While geologists tend to think of boreholes in terms of chips and core, geophysicists perceive them first and foremost as access paths for instruments. Borehole logging has been employed at iron and coal mines for decades, mainly to accurately define ore boundaries in delineation holes. In base metal mines, Outokumpu implemented logging widely for orebody delineation in percussion holes in the 1980s. The benefit was a direct cost-saving, arising from substitution of core drilling with percussion drilling plus borehole logging. The practice has since spread to other companies. INCO, for example, defines nickel boundaries in blast holes at Sudbury using conductivity logs. The benefits are in the form of reduced dilution and enhanced ore recovery, flowing from a more accurate mine model. Density, natural gamma radiation, magnetic susceptibility, and conductivity are the principal metalliferous mine logging parameters because they can be recorded in both dry and water-filled holes. Sonic velocity is the premier geotechnical logging parameter, given its sensitivity to rock strength, stress, porosity, and degree of fracturing. Sonic is recorded routinely in exploration and geotechnical holes at coal mines. With the advent of slimline dipmeter, full waveform sonic, and optical and acoustic scanner tools, the role of borehole logging in geotechnical evaluations is expanding. Monitoring of strain and micro-seismic activity enhances safety during mine production. While qualitative interpretation of logs is adequate for stratigraphic identification or definition of boundaries, a wealth of quantitative information, eg density, can be derived from properly calibrated, repeatable geophysical logs. Moreover, geophysical logs can sometimes serve as surrogates for geochemical assays, and not only for magnetite and uranium. At OutokumpuÆs Kemi chromite mine, for example, gamma-gamma logging provides the basis for grade control. By reducing reliance on assaying, three benefits can be realised: reduced reliance on core drilling; lower core handling and assaying costs; and shorter turn-around times. Conventional downhole EM and borehole magnetics are used for near-mine exploration, and for ground sterilisation. Inco has enjoyed considerable success with borehole UTEM in the Sudbury Basin, for example, and Geopeko has applied three-component borehole magnetics successfully in the Tennant Creek area. Electrical techniques such as applied potential and magnetometric resistivity (MMR) are also finding application at mines. For higher resolution, borehole seismic, radio imaging, and radar have been invoked, with varying degrees of success, to delineate orebodies and map structures, or to geotechnically characterise the rock mass and identify hazards. Success mapping nickel sulphide shoots with borehole radar has been reported by WMC at Kambalda. There are no universal geophysical panaceas, and each mine imposes different geological, logistical, and economic constraints. Geophysics will not always be cost-effective. However, the greatest single impediment to expanded use of geophysics at mines has been the low level of awareness of geophysics on the part of most mine geologists, engineers, and managers and, equally, the limited understanding of mine geology and engineering exhibited by the majority of geophysicists. This myopia will be remembered as a 20th century affliction! Blue Sky areas for mine geophysics in the next ten years include integration of geophysical data acquisition with drilling, enhanced grade estimation and rock mass characterisation, and the incorporation of geophysical information into mine models using geostatistical techniques. All these advances will be predicated on an expansion of petrophysical knowledge.

Jan 1, 2000

Iron formation-hosted iron ore deposits account for the majority of current world iron ore production and consist of three classes: unenriched primary iron formation with typically 25 to 45 wt per cent Fe; martite-goethite ore formed by supergene processes, with abundant hydrous iron oxides containing 60 to 63 wt per cent Fe; and high-grade hematite ores thought to be of hypogene or metamorphic origin overprinted by subsequent supergene enrichment with 60 to 68 wt per cent Fe.Individual iron ore deposits range from a few millions of tonnes to over two billion tonnes at >64 wt per cent Fe, although most are within the range of 200 to 500 Mt. In the Hamersley Province of Western Australia, martite-goethite ores are largely developed in the Marra Mamba Iron Formation, although high (>0.08 per cent P) phosphorous mineralisation is also well developed in the stratigraphically higher Brockman Iron Formation. Whilst the vast majority of high-grade microplaty hematite ore is best developed in the Brockman Iron Formation, this paper provides the first textural evidence of locally significant microplaty hematite mineralisation in the Nammuldi Member of the Marra Mamba Iron Formation, in the Chichester Ranges at the Christmas Creek, Cloud Break and Mount Nicholas prospects. Petrographic studies have identified a high-grade Fe texture composed of nanometre scale plates of hematite in mineralised sections of primary microplaty hematite deposits in the Pilbara and elsewhere, well below the normal depth of weathering or dehydration. The population of nanometre to micrometre scale hematite plates is interpreted to represent various stages of nucleation, crystallisation and progressive growth of hematite from the primary ore-forming fluid in areas that were once iron-rich carbonates or silicates in the BIF.

Jan 1, 2005

Surface and near surface particulate gold occurs sporadically over an area of some60 km2 between Vunda and Navilawa on the west coast of Viti Levu, Fiji.Background grades of 0.01 ppm can be found in the zone of weathering from 3 to ZQm but, at Vunda, attain significance within certain "localities" ranging from 1000 m2 to 35000 m2 in area. Intense and deep weathering renders geological interpretation difficult but the higher grades seem to relate to equally weathered dykes and apophyses which intrude the tuffaceous country rock.Both country rock (5.4 m.y.) and intru-sives (4.8 m.y.) are of shoshonitic composi-tion and all rocks are consanguineous. At Navilawa, on the eastern end of the zone, basic monzonite crops out as a sizeable stock carrying low grade porphyry-type copper and gold. Between Navilawa and Vunda intrusives are as large apophyses and dyke swarms, and at Vunda, on the western end, only the upper ends of dykes and small apophyses are exposed carry-ing various sulphides, magnetite and rutilein hair line fractures. The level of erosion is thus deeper to the east and shallower to-ward tha wPst_

Jan 1, 1984

By M A. Wells

The various mechanisms by which phosphorus (P) occurs and is distributed within banded iron formations (BIF)-derived iron ore are examined. In unenriched, precursor BIF P occurs predominantly as discrete grains of primary apatite. In high-grade ores hosted mainly by the Brockman Iron Formation, P occurs in three main forms:1. as secondary apatite;2. other submicron, P-rich phases (eg Rare earth containing minerals (REE), vivianite, strengite,wavellite) present in pore networks; and3. as P occurring with iron oxides, in particular, goethite.However, the presence of secondary P-bearing phases does not contribute signifi cantly to the total P level in iron ore, and it is P associated mainly with goethite, which represents the most common occurrence of P in these ores.No direct evidence for the replacement of Fe by P within the structure of synthetic goethite has been demonstrated. Therefore, it is most likely that in iron ores P associates with goethite in occluded form as adsorbed PO4 3- species or as discrete P-bearing minerals, such as strengite, wavellite or vivianite, in ultra-fine, micro-pores or within intra-domain regions of multi-domainic goethite. Such occluded P is not easily extracted with commonly used lixiviants, such as weakly alkaline leachates. Recent development of a low temperature-alkalie/water leach extraction method has been successful in reducing not only the P content, but also amounts of Si and Al inthe initial ore. Refi nement of such a method to commercial application will have enormous benefit in realising the economic potential of large tonnages of high-P (ie >0.07 wt per cent P) bearing iron ore.

Jul 11, 2011

By R Carreau

The results of a detailed acid rock drainage (ARD) prediction program were used to revise the waste rock segregation criteria at the Restigouche open pit mine. Waste rock at the site was predominately derived from altered volcanic rocks that hosted a massive sulfide lead/zinc orebody. The program assessed the five years of drainage chemistry from both the potentially acid generating and the non-acid generating waste rock storage facilities in addition to laboratory-based kinetic test results. Material-specific leaching characteristics including relative metal-release rates and neutralisation potential depletion rates were determined from 12 laboratory-based kinetic tests. Solid-phase analyses indicated that, although pyrite was typically the most abundant sulfide mineral in the waste rock, its abundance varied significantly as documented by total sulfur contents ranging from 4.0 per cent. Kinetic test results were used to establish revised waste rock segregation criteria based on total sulfur content and neutralisation potential. The revised criteria maintain that waste material with a total sulfur content 4.0 per cent as potentially acid generating. When present in sufficient quantities, ankerite provided an effective source of neutralisation potential for the range of observed sulfide oxidation rates. Kinetic testing documented that up to 6 kg CaCO3/t was ineffective at neutralising acidity in samples that contained >4 per cent S. The carbonate molar ratio measured from the humidity cells was adjusted to reflect the stoichiometry of the ankerite and applied as an NP/AP criteria for waste rock containing 0.1 <S per cent <4.0.

Jan 1, 2003

Jan 1, 2004