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By Woodcock J. T

When an aqueous suspension of pyrite and a manganese ore reacts with oxygen, manganese is dissolved by the ferrous sulphate and sulphuric acid produced in situ by oxidation of pyrite. In the absence of added acid, the optimum conditions are: a molecularratio of Mn02/FeS2 of about 1·0, a temperature of about 1400 C., and an oxygen pressure between 25 and 90 lb./sq. in. Under these conditions, complete extraction of manganese is obtained in six hours leaching. An addition of sulphuric acid enables an Mn02/FeS2 ratio of 2·0 to be used successfully.Manganous sulphate decreases in solubility with increase in temperature above 1000 C., but even when the solubility limit is reached during leaching, reaction to form MnS04 still proceeds, and on cooling the MnS04 redissolves.INTRODUCTIONMany manganese deposits contain secondary manganese oxide minerals which are difficult to concentrate. Considerable attention has therefore been given to their hydrometallurgical treatment. In most manganese oxide minerals, the manganese is quadrivalent and must be reduced to the divalent state for dissolution. Reduction and dissolution can be accomplished in a number of ways, one method being to use aqueous ferrous sulphate solutions.A possible source of ferrous sulphate is pyrite as it is known that ferrous ion is an intermediate product in the aqueous oxidation of pyrite. It was therefore thought possible, that by heating an aqueous suspension of manganese oxide and pyrite with oxygen, the ferrous sulphate and sulphuric acid formed from pyrite would provide the necessary leaching reagents for manganese in situ. There are certain advantages in producing ferrous ion in situ...

Jan 1, 1958

By R Edwards

Greater efficiency of capture of minus 6 mm to fine micron size particles of free gold is achieved with the Knelson Concentrator. The development, principles of operation and recent innovations relating to this enhanced gravity concentrating device are described by the inventor, followed by a description of application and consequent economic benefits in low grade alluvial gold deposits by a large scale user of Knelson Concentrators in the Northern Territory of Australia.

Jan 1, 1990

Development of New Comminution Testing Methodologies for Geometallurgical Mapping of Ore Hardness and Throughput The emerging discipline of 'geometallurgy' is becoming increasingly recognised as a discrete and high-value activity that reflects an ongoing trend towards more effective mine site integration and optimisation. Constrained sampling that reflects and defines inherent ore body variability is a key geometallurgical requirement. This requires use of larger numbers of low-cost physical testing which can be applied to small sample volumes suitable for defining natural variability. The AMIRA P843 'GeMIII' project (Geometallurgical Mapping and Mine Modelling) is a major industry-supported research initiative designed to develop new tools, methods and protocols to support geometallurgical integration. As part of this integrated research a new more rapid low-cost comminution test (GeM Comminution index) has been developed which can be employed as a front line tool for geometallurgical mapping purposes and predictive throughput modelling. The test has been designed to be inserted into routine assay sample preparation and is based on constrained jaw crushing protocols linked to analysis of resultant size distributions. Extensive validation and modelling has shown the GeM Comminution Index (Ci) is correlated with the Drop Weight index A*b and Bond Mill Work Index (BMWi). Large scale trials have been conducted within a commercial assay laboratory to demonstrate and optimise incorporation of the Ci test into routine sample preparation protocols. While Ci based estimates of A*b and BMWi are not as precise compared to larger volume more expensive test-work, the ability to undertake large numbers of tests typically in a systematic down-hole manner, provides a high level of data support through adjacency. A Ci based approach is highly suitable for variability mapping, domaining and selecting large composite samples for more precise testing. Within the context of the AMIRA P843 project this forms part of an integrated work flow designed to support geometallurgical integration. The development of a comminution test linked to routine assay sample preparation represents significant value adding to a process that in most cases is already going to be carried out. This paper introduces the Ci test concept and application to geometallurgical testing for throughput modelling

Sep 13, 2010

Extraction and Characterisation of Extracellular Polymeric Substances from the Mineral Surface During Bioleaching of Chalcopyrite Concentrate A mixed culture of moderately thermophilic microorganisms was used to bioleach chalcopyrite concentrate in a stirred tank reactor. The results show that up to 84.7 per cent of copper extraction could be achieved in 24 days at a pulp density of 6 per cent. The leaching rate of chalcopyrite concentrate tended to increase with an increase of dissolved total iron concentration. Furthermore, the extracellular polymeric substance (EPS) on the surface of the chalcopyrite concentrate was extracted and analysed. EPS was extracted at the first, third, eighth, 16th and 24th day during bioleaching, which mainly consisted of proteins, lipids, sugars and ferric irons. After the eighth day the total amount of EPS remained relatively constant. However, the amount of ferric iron in the EPS decreased in a large scale. The ore residue analysis indicates that the decrease of ferric iron was mainly due to the formation of jarosite on the mineral surface.

Sep 13, 2010

Raw materials account for over 60 per cent of the cost of hot metal production in classical blast furnaces and the principal cost component is cost of coke. Dependence on coke is a traditional weakness of blast furnace ironmaking and while efforts have been made to evolve alternative ironmaking technologies which do not use coke, such as direct reduction, smelting reduction, and the more recent method of making iron carbide, blast furnaces continue to be the most efficient means of producing bulk hot metal even today. Coal injection, to the extent of 150 - 200 kg/t of hot metal, has been one of the major innovations made in blast furnaces to decrease cost and to reduce the dependence on coke. This has, however, given rise to more stringent coke property requirements (which often means more expensive coke) - a `tail spin' of Sorts!

Jan 1, 1999

An intensely sheared and mineralized zone occurs in the quartz dolerite greenstone (or younger greenstone) mass on the western limb of the Kalgoorlie syncline. This zone comprises the western part of the Golden Mile and has produced the greater part of the 33,000,000 oz of gold produced to date from the main mining belts. A study of the general geological and structural features suggests that the lode shear system will continue southward on a pitch similar to that of the main syncline. Although payable ore has been found recently further to the south, the expectation of large quantities extending southward from the present mining areas is problematical.INTRODUCTIONUntil the late 1930's the principal mining activities in the western lode system were centred on three major ore-shoots formed on the No. 4, No. 3 and to a lesser extent on the No. 2 lode shears (Fig. 1). With the gradual reduction of grade in depth on these main ore shoots, increasing attention was paid to the "Minor Lode" system of lode shears known to exist in the same area. A large quantity of payable ore was found on these "Minor Lodes" particularly in the central part of the mining area. In recent years more attention has been given to exploration in a southerly direction.ROCK TYPES AND STRUCTURESThe western system occurs on the western flank of a dragfolded, south pitching syncline. The rock succession consists of Black Flag sediments overlying the younger greenstone horizon which overlies the fine grained older greenstone horizon. The axis of the syncline is regarded as a tight infold of the overlying Black Flag sediments. This infold has been faulted and intruded by albite porphyry resulting in the formation of a composite body of slates...

Jan 1, 1964

By B Leisemann, M Watkinson

Coal augering is an ideal method for recovering coal from the highwalls of open cut coalmines. Coal augering is a simple process whereby additional flights are added to the auger cutting head and auger holes are drilled at 1.9 m diameter up to 200 metres deep. Traditional monitoring was located at the mouth of the hole and if methane was encountered above two per cent, inert gas was delivered into the mouth of the hole to deplete the oxygen content at the auger cutting head below 12 per cent. The auger operator was asked the question ‘how do you know that this is the case?’ Trials were undertaken to prove that the oxygen content at the cutting head did drop below 12 per cent (the lowest limit for methane to ignite, also known as the oxygen nose point). Initial trials showed that the oxygen content in the mouth of the hole did not drop below 12 per cent and modifications were made to hold the inert gases in the mouth of the hole so that the auger flights could take this inert gas into the hole. In-hole monitoring, after completion of mining and after extracting the auger flights, showed that the atmosphere quickly returned to fresh air. In-hole monitoring was also tried during the augering process and yielded valuable results. This paper will discuss the results of the monitoring, information on the gas results obtained and the methodologies used to optimise the oxygen content at the auger face.CITATION:Watkinson, M and Leisemann, B, 2017. Inertisation of coal augering holes, in Proceedings Australian Mine Vent Conference 2017, pp 293–298 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

THE area dealt with in this paper is included within a radius of about 3 miles of the Poimena township. Several thousand tons of tin have been won from this field, and probably £200,000 spent in exploiting it.PREVIOUS LITERATUREThe field has been reported on by Government geologists on four occasions and several ,articles on it have appeared in the mining journals. The work done by Government geologists is summarized below:-"Report on the Blue Tier Tin Mining District and its Tin Deposits", 1886.Speaking of the tin-ore occurrences, this paper states:-"In the primary granite the lodes of tin ore occur, also dykes and belts of more recently obtruded porphyries. The really valuable metalliferous deposits may be classified as follows :-1. Lodes (of which the Lottah mine is typical).2. Dykes- (a) Indurated or hard (as shown by the formations at the Anchor and Cream Creek mines). (b) Soft (eg Hayley's Lease).

Jan 1, 1912

The provision of professional engineering services in Queensland is regulated through the Professional Engineers Act 2002. The Act requires that anyone providing professional engineering services must be registered and is subject to continuing professional development requirements. The engineering profession is actively requesting the Queensland Government to expand registration to include associate and technologist engineering practitioners. In view of the strong moves at the Federal level towards national registration of professional groups the lessons of the Queensland experience are very relevant across Australia. This paper describes the rationale behind the Act and outlines its operation. It discusses some misconceptions regarding the applicability of the Act to various engineering activities. There is much that the Act has to offer individual engineers and industry generally in establishing, articulating and maintaining standards for professional engineering work. The paper considers legal actions taken to date under the provisions of the Act and discusses the way in which this parallels industry moves towards quality assurance of work force capability.

May 1, 2010

Technologies are receiving a lot of 'press' - and rightly so; as they are seen as the means for achieving quantum leaps in productivity and cost reductions. A point of concern for Caterpillar is that we do not believe there is enough understanding of the infrastructure needed to support some of the future technologies, as well there is not enough utilisation of the current systems.

Jan 1, 1997

By M Rafty, A Markham, S Atkinson, M Heyting

Over recent years there has been a significant increase in the number of miners in the Pilbara region of Western Australia targeting channel iron deposits (CID) located in valleys, intersected by ephemeral creeks and below the groundwater table. The falling iron ore price has triggered a drive to reduce cost and maximise yield. Creek diversions provide an opportunity to maximise the utilisation of orebodies and extend the life-of-mine.Creek diversions that are required during mining operations to access ore and provide flood protection have historically been constructed as uniform engineered channels designed primarily for flow conveyance while minimising earthworks costs; however, the design of diversions becomes more complex when they are required to function in a similar way to the existing creek system during operations and remain stable during more extreme events than would typically occur following mine closure, in accordance with current regulatory guidance. The design specifications for closure are often more rigorous than the operational phase, and could incur significant additional cost to implement retrospectively if not planned and designed upfront.The complexity of diversion design depends on site specific factors such as: the size of the creek to be diverted; hydrology; corridor restrictions; geomorphology; hydrogeology; geology; environmental and heritage values; potential impacts and the risk to operations and environment. The complex interactions of these factors must be well understood and hydraulic modelling undertaken to characterise the existing creek system, demonstrate the diversions, provide adequate flood protection during operations, and can function in a similar way to the existing system following mine closure. This paper presents key design considerations for Pilbara creek diversions, operational and closure requirements, mine planning considerations, risks, cost saving opportunities, and the benefits of an integrated approach to design.CITATION:S Atkinson, A Markham, M Rafty and M Heyting, 2017. ‘Back to the future’ – resilience in historical context and implications for the future, in Proceedings Iron Ore 2017, pp 367–374 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Base metal sulphide mineralisation on the northern end of Great Barrier Island is spatially associated with hypabyssal intermediate to acidic intrusives, in transgressive structures in indurated, complexly deformed greywackes and argillites. Copper predominates in the mineralisation, with minor accompanying lead and zinc and also some gold and silver. However, in some cases lead or zinc may be the dominant constituent. The mineralisation is generally characterised by only narrow envelopes of weak alteration (propyliticassemblages dominated by chlorite and epidote) and with only minor amounts of quartz accompanying the sulphides, which form a cement in zones of hydraulic fracturing. There are two distinct structural settings to the mineralisation: at MinerÆs Head, in a structurally complex situation in a shell-like zone of crackling in hornfelsed greywacke, in association with both north- and east-striking fractures and rubble breccias associated with the apical part of a large intrusive; and in very narrow, but very strike-persistent, 1inear steeply-dipping fracture zones, exposed on the north coast and inland areas near Tataweka.

Jan 1, 1984

By K Ehrig

You are a geologist, geometallurgist, or metallurgist/process engineer and are fortunate enough to work for an organisation who asks you to design/execute a geometallurgy program. What seems like a simple request is actually not a trivial exercise. æRecipeÆ style manuals are not readily available. However, many æexpertsÆ are lurking around willing to deliver solutions which will solve all of your problems. Even though similar ore deposit styles (e.g. porphyry Cu, IOCG, Ni-laterites, calcrete hosted U, etc.) have many similar characteristics, each ore deposit is unique. Hence your geometallurgy program needs to be æfit-for-purposeÆ. This paper offers some insights gained via designing and executing geometallurgy programs from exploration through to production, and working at a mine where you are held accountable for your metallurgical performance predictors.CITATION:Ehrig, K, 2013. Geometallurgy - What do you really need to know from exploration through to production?, in Proceedings MetPlant 2013 , pp 28-33 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

Grinding Mill Operation and Maintenance - Central to Asset Management Since 2005, RME has pursued a vision for a new grinding plant operational paradigm, made possible by RME's latest Mill Relining Systems. At some sites, new liners degrade SAG mill performance. The variables include mill volume loss, rotational speed limitations (ball strike) and liner designs developed for longer and longer life but without a backward glance at metallurgical consequences of whole plant performance. Freshly relined mills can initially deliver as little as 80 per cent of their maximum throughput, that maximum occurring toward the end of the liners' wear life. RME's proposition is to see new liners designed for maximum commercial performance. This may mean more frequent mill relines but with liners designed to yield optimum grinding, metallurgical and profitability performance, not maximum life. In other words, mill liner profiles and relining speed become key profitability contributors and not simply 'must do' maintenance functions and costs. This paper includes a short history of RME's Mill Relining System development (Appendix A). These are the enabling technologies which permit more frequent liner exchange without incurring additional downtime imposts. The body of this paper outlines RME's vision of a 'liner profile vs. profitability' commercial model, underpinned by the rigour of PAS 55-1:2008 Asset Management Part 1: Specification for the optimised management of physical assets. The technical elements can be developed either intuitively (based on plant experience) or by using a combination of new measurement and modelling technologies. These new measurement and modelling tools provide the opportunity to predict the optimum technical solution for the maximum commercial outcome. Much of this can be modelled off-line, in the virtual world, before asking senior management to commit to an expensive liner experiment. The potential benefits are compelling.

Sep 13, 2010

By Pilon CG, Deakin RC

It is proposed that a waste rock dump be constructed on slopes consisting of soft colluvium and weathered Chim Formation mudstone at the Porgera Gold Mine, in Enga Province, Papua New Guinea (PNG). Geolog- ical, geomorphological and geophysical investigations were conducted in support of geotechnical studies to assess the physical character of the 6km2 site. Geomorphological studies focused on the extent and nature of colluvium cover and landslide activity. Detailed ground traverse mapping resulted in classification and delineation of eight terrains and seven material types. Seismic refraction and resistivity profiling, combined with drilling, provided subsurface data. Results were presented as standard profiles, coloured contoured sections and plans. Subsurface features, including deep colluvial channels, buried cliffs, slump blocks and buried alluvial channels, were identified. Results of the combined investigations allowed designers to model the colluvium/ bedrock surface and identify critical areas of deep, mobile colluvium and weak bedrock. A design approach was developed which accounted for the morphology of landslide systems and distribution of colluvium types.

Jan 1, 1991

By Mehrotra G. M, Frohberg M. G

Based on the concepts of statistical thermodynamics of athermal mixtures, an approach is developed which is capable of quantitatively explaining the thermodynamic properties of binary silicate systems. Expressions for the ionic fractions of various anionic linear and nonlinear chain polymers are derived. The developed expressions for free energy of mixing are tested by applying these to the system PbO-SiO2. The ionic fractions of various chain polymers in this system are calculated. The two cases, namely, of linear and nonlinear chain polymers are compared with each other.Limitations of earlier models are pointed out.

Jan 1, 1975

Application of the Anaconda Simplified Work Index for Multiple Test Sizes Vale uses Bond Work Index measurements extensively in a number of applications. The Bond Work Index is usually a good parameter for checking scale up procedures when sizing ball mills, as well as the basis for variability analysis whenever drill core data is available. It is typical to measure between 100 and 150 Bond Work Indexes, depending on the deposit characteristics. The Bond procedure is relatively complex and time costly. It also requires relatively large amounts of sample, which are very expensive to be obtained. The benefits of the Anaconda simplified procedure are: considerably smaller sample requirements and laboratory time. This makes it very much attractive at Vale's development centre, including geometallurgical mapping, operation efficiency control, mine to mill, etc. The Anaconda simplified procedure was implemented and evaluated at Vale's Development Centre using a number of ores and several samples of each ore totalling more than 190 measurements. The Anaconda simplified method was calibrated for several test sieves and a correlation for any test size was determined for Vale's test mill. The calibration was also extended for two sample top sizes. The relative error of the simplified procedure was found to be in the range of nine per cent which is within the expected error Bond standard procedure. The implementation of the Anaconda method at Vale's development center has been used with great success over the past years in several green field, brown field projects and operating plants.

Sep 13, 2010

By D Crequer

Land rehabilitation at Golden Cross is reviewed, 8 years after mine closure in 1997/98, from the perspectives of a Peer Reviewer (land rehabilitation) and a Regional Council Officer (Resource Consents compliance). Land rehabilitation items we discuss include: management of restored pastures, native plantings (on-site riparian and block plantings and off-site environmental riparian enhancement plantings), wetlands (on-site tailings lake and sediment ponds littoral zone plantings, and basement of the open pit; and off-site wetlands enhancement plantings), pine plantations on-site and on surrounding land, stabilization of the Tailings Lake Embankment (landslide) and Open Pit capping, capping of acid-mine-rock, stability of discharge channels, buildings and amenities, public access for recreation, educational uses, and future management of the site. Pest control has helped to conserve the rare and endangered HochstetterÆs (Leiopelma hochstetteri) and ArcheyÆs (L. archeyi) frogs, and a regionally significant stand of rare swamp maire (Syzygium maire) has been conserved and fenced.

Jan 1, 2006

By I M. Platten, Y Xie

Complex gold deposits are generally characterised by variable geometries, strong structural controls on grade distribution and a high-nugget effect. The use of diamond drilling and fire assays in this environment often results in an understatement of grade. Bulk samples are likely to be the closest estimators of true grade, and may be required to evaluate geological/grade risk during resource estimation/feasibility studies. Any bulk sampling program requires appropriate planning and implementation. The planning stage should attempt to delimit the extent and nature of mineralisation; characterise mineralogy and metallurgical properties of the ore; and define bulk sample size and how it will be sampled/processed. The approach to sample processing will be governed by the results of metallurgical testing and geological knowledge. Careful design of sampling protocols must be undertaken through material characterisation, understanding of gold particle sizing and the application of GyÆs Sampling Theory.

Jan 1, 2008

Rational decision making is generally perceived by managers of operations to be a delicate process of committing large sums of money and putting other people's life at risk. Consequently most managers may argue that the decision process requires good judgement, intuition and extreme caution; and not one easily made through the use of fancy mathematical algorithms and computer programs. The advent of artificial intelligence and expert systems in the computer industry combined with recent technological innovations in mathematical and economic problem solving is sure to change this perception. PARETO OPTIMALITY is an economic and a mathematical optimisation concept applied to solving real life operational problems; and one that the current volatile economic forces would require managers to employ because it is virtually real. REALISMM is a computer software package developed using the principles of Pareto optimality, dynamic programming, optimal clustering of information and decision maker interaction to generate decision maker preferred solutions. REALISMM has scope for artificial intelligence and expert systems application for cases where the decision maker is unsure about his objective preferences.

Jan 1, 1993