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Fire-clay blocks lining the combustion chambers of zinc concentrate flash-roasting, furnaces operating at 1,000-1,200° C. have suffered moderately rapid deterioration due to slagging. The attack is accentuated by high temperatures, and is probably caused by lead oxide volatilized from the roasted concentrate.Resistance of refractories to attack increased with increasing alumina content from 30 to 45 per. cent but at 90 per cent alumina spalling was troublesome. Magnesite bricks were'subject to some spalling, but some types may lie satisfactory. Chrome and chrome-magnesite bricks spalled seriously.Material thought to be suitable for use as a monolithic lining slagged badly and an alternative may be tested.INTRODUCTIONThe Electrolytic Zinc Company of Australasia Ltd. uses two multi-hearth furnaces and four flash or suspension roasting furnaces for the roasting .of zinc concentrates at its Risdon Works. The hearth roasting plant has been described previously by Forster (1949).A brief descriptioI1 of the first three flash roasters was given by Gordon and Forster (1955). A fourth flash roasting furnace began operation early in 1957. This furnace is somewhat larger than the earlier furnaces, and the designed capacity is also higher, auxiliary equipment being altered to suit. An important structural difference between the older furnaces and the fourth flash roaster is that the walls of the combustion chamber of the new furnace are lined with high alumina fire-bricks instead of fire-clay blocks. Thischange was made because the fire-clay blocks in the older flash roasters had shown s-evere wastage due to slagging by lead derived from the concentrate.

Jan 1, 1959

The mineralogy of the rocks now observed in the Nairne pyrite deposit developed under conditions of internally-controlled sulphur activity during amphibolite facies metamorphism. In the sulphide-deficient metasediments the activity of sulphur was low, and pyrrhotite developed with iron-bearing silicate minerals. At higher sulphur activity, in the sulphide-rich meta-sediments, pyrite formed in addition to pyrrhotite, and the associated silicate minerals are iron-deficient.

Jan 1, 1969

By Turner WG, Short RR

Obviously, the paramount advantages of contract mining have been recognised by mine developers throughout Australia, as evidenced by surface gold mining operations of significant output almost exclusively being performed under contract. These paramount advantages of using an experienced professionally managed contractor result from the mine developer being freed from financing the required relatively large capital expenditure at current relatively high interest rates or in a capital scarce stock market, and from the need to recruit and sustain a large operating work force in a competitive labour market.

Jan 1, 1990

Comparison of Grinding and Liberation Processes for Stalky Biomass Materials as a Prerequisite for Production of Energy Pellets with High Calorific Value Pelletising biomass, especially straw and stalky materials, requires a product specific size reduction and liberation. However, moisture content plays an important role in palletising and also affects the energetic properties of the biomass. The paper illustrates the characteristics of the mentioned type of biomass and specifies the necessities for production of energy pellets. Defined requirements for biomass energy pellets will be shown based on relevant standards. The work focuses on a comparative investigation of the straw fibres after grinding with hammer/impact mill and after the liberation of the straw fibres with twin-screw extruder (two different communition units). A traditional hammer mill as well as an hydrothermal process taking place in a twin-screw extruder were utilised. Results of the grinding and liberation of rye and wheat straw fibres are discussed based on a detailed particle characterisation (particle size and shape distribution). Besides high calorific value the main pellet quality parameters are mechanical stability, abrasion resistance and further combustion technical characteristics. The particle size distribution displayed optimum characteristics for the combustion processes to be carried out in a furnace. The durability of the pellets produced from straw fibres liberated with twin-screw extruder was comparatively better then that prepared with the straw fibres after grinding with impact mill. Particle size distribution, abrasion values and the strength characteristics showed a good correlation with each. The high presence of N and S would result in high NOx and SOx emissions, where as the high concentrations of Cl would corrode the furnace. These chemical properties of the straw would restrict its usage in small scale furnaces.

Sep 13, 2010

By D Craw

Formation of gold-bearing veins in Otago Schist was intimately linked to the structural evolution of the schist belt. The currently-exploited Macraes gold deposit formed in a regional scale shear zone during latemetamorphic uplift of the schist belt. Further exploration for this type of deposit will be facilitated by an increased understanding of the late-metamorphic structural evolution of the schist belt. To this end, a three-dimensional cross section through the Otago Schist has been drawn using structural data gathered at outcrops in a 20 - 40 km wide transect across central Otago. This is the first continuous detailed structural section to be drawn through the belt. The section spans an area from Textural Zone 1 metagreywacke of the Torlesse terrane in the northeast through TZ 4 schist in the central region and across the Caples-Torlesse boundary to Textural Zone 3 schist of the Caples terrane in the southwest. Two different late-metamorphic structural generations are identified in this section: the long-recognised Manorburn Generation, and a new æPoolburn GenerationÆ. The location of the Caples-Torlesse boundary has been refined on this transect by field mapping combined with whole rock geochemistry.

Jan 1, 2001

Ground conditions at the Kencana mine, Indonesia, are generally poor and an underhand cut and fill mining method is used for extraction. Due to these poor ground conditions, all vertical development has been conducted using blind, top-down, sink and line excavation methods. Due to time constraints, raiseboring was considered the only viable excavation method for the installation of a return ventilation system for the K2 (Kencana extension) project. In order to achieve successful raiseboring in the poor ground conditions a number of strategies were used including: a detailed geotechnical study for optimal position of the shaft/s, splitting shaft excavation vertically, raiseboring of multiple smaller diameter shafts, extensive pregrouting, installation of drainage holes, and rapid installation of support following excavation.

Nov 25, 2010

Copper waste dump leaching is growing in importance because of the.large tonnages (up to 250,000 ton/day) of low grade waste rock available from open cut mining of copper deposits and proof that controlled leaching of copper from such dumps can be profitable.Overburden or waste rock, ranging in size from large boulders to fines, is dumped as cheaply as possible on sloping sites. Copper is leached from the dumps by applying up to 12,000 gal/min of leach solution (a combination of spent solution from cementation and make-up water) to the top of the dumps by various techniques.Efliuent from the dumps is sent to a cementation plant for copper recovery.Factors which may be controlled, either directly or indirectly, to give a controlled copper content in the dump efliuent (usually 1-2 g/l.) are the cycle of operations (i.e. the alternate wetting and drying periods), thevolume of solution applied to the dump, pH, Fe2+ and Fe3+ content or redox potential, oxygen content, bacteria and their necessary nutrients, and temperature.Dissolution of oxide copper minerals appears to be mainly a function of acid concentration. Copper sulphide minerals need oxidation for dissolution to occur and this is accomplished by a combination of oxygen,ferric ion, and bacteria. Oxidation of pyrite, oxidation of Fe2+ to Fe3 +, and hydrolysis of Fe3+ are of some importance in leaching practice. The presence of gangue carbonate minerals is detrimental.Physical factors connected with penetration of solution into large rocks are important and the treatment of an individual dump usually extends over a period of many years. Recovery of copper from solution is usually achieved by cementation with iron (usually in the form of crumpled cans) but the use of sponge iron is becoming more important. Iron consumption varies from 1 to 4 lbiron per pound of copper. Preconcentration of the copper in the efliuent solution by solvent extraction followed by electrolysis may become a useful method.Application of dump leaching techniques to metals other than copper depends on finding an economic method of recovering the metal from solution...

Jan 1, 1967

By B Murphy, A Uliana, P STrgio de Oliveira, G Ara·jo de Souza Franco, T Miettinen

Outotec has performed numerous research and development projects and various surveys in the study of reverse iron ore flotation. Over the past four years their TankCell-70 and TankCell-160 flotation cells at the Germano concentrator of Samarco in Brazil were extensively surveyed. These surveys have revealed some extreme operating conditions in reverse iron ore flotation and are the subject of this paper. Some of the findings include large variations in the content of solids in the various flotation stages. At the bottom of the cleaner cells, the content of solids by weight reached over 60 per cent, whereas at the bottom of the scavenger cell this was less than 50 per cent. Froth carry rates were also significantly different in the various flotation stages. In the case of coarse material, the scavenger cells operated at a froth carry rate of over 40 t/h.m2. With fine material, however, froth carry rates of less than 10 t/h.m2 were measured. High froth carry rates caused significant changes in the residence times at Samarco. In the rougher cells, the fifth cell had more than double the residence time of the first cell. This was even more pronounced with the scavenger cells, where the second cell had more than triple the residence time of the first cell. High froth carry rates also caused losses in iron recovery. As a consequence of such findings, it appears that different rules apply in the sizing of reverse flotation circuits compared to direct flotation circuits. Different operating parameters (mixing intensities and air flow rates) must also be used in the rougher, cleaner and scavenger cells in order to optimise the metallurgical performance. Outotec has also been working on a number of new technologies aimed at improving the metallurgical performance of iron ore reverse flotation circuits by increasing froth carry rate and decreasing fine iron entrainment.CITATION:Miettinen, T, Uliana, A, Ara·jo de Souza Franco, G, STrgio de Oliveira, P and Murphy, B, 2013. TankCell flotation at SamarcoÆs Germano concentrators, in Proceedings Iron Ore 2013 , pp 441-444 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

Three large deposits of good quality lignite were located and delineated in the Central Otago region between October 1978 and July 1979. The program was initiated and funded by Mines Division of the Ministry of Energy as part of the national Coal Resource Survey. The exploration work was carried out by Lime and Marble Limited on a contract basis (Bowman, 1980). The three deposits were all potentially mineable by open cast methods and possessed combined indicated and, inferred reserves in the order of 1000 x 106 tonnes. They ranked with the previously discovered Eastern Southland 1ignites and as such constituted an important national energy resource. Fifteen months later a second more detailed investigation of similar duration was undertaken by the Liquid Fuels Trust Board (LFTB). The objective was to upgrade and refine the geological data base of all of the nine South Island 1ignite deposits in order to make preliminary economic assessments of their potential. Again Lime and Marble Limited acted as the exploration operator (Bowman, 1981a, 1981b, 1981c).

Jan 1, 1983

Evaluation of Grinding Medium Wear in Stirred Mills The standard fine grinding machines in the minerals industry are stirred mills whose performance largely depends on the competency of the grinding medium. Medium wear in stirred mills is one of the key parameters for medium selection. A wear evaluation methodology is developed and applied in this paper to measure the wear rate of river sand using a laboratory batch stirred mill. The procedure is demonstrated by testing the sand medium in a 0.55 kW batch stirred media detritor (SMD). The sand wear rate determined in the laboratory batch mill is successfully scaled up to that determined on a full-scale Metso 355 kW SMD mill.

Sep 13, 2010

The Australian mining industry is at an interesting stage in its development. Of the large number of mining companies in Australia, some are still solely domestic in their focus, others have made their first tentative forays offshore, and others are global players of significance in tile world industry.   It is not long ago that the entire industry was almost exclusively domestic in its focus. Very few companies before the early 1980s had ventured offshore, and those that did so were considered quite risque. The initial moves were made mainly by large companies who could afford to lose the funds expended in getting started in a range of offshore locations.   Almost all offshore jurisdictions were considered to be high risk compared to the safety of home - I recall the extreme difficulty I encountered in the mid 1980s in endeavouring to persuade a Board to joint venture into an attractive gold opportunity in South East Asia.   One of the problems inhibiting the offshore development of the Australian mining industry was that some mining companies had had unfortunate experiences offshore. Others had heard of those who had had unfortunate experiences offshore and, as such, 'offshore' gained a bad name and the more risk averse boards and. management of the time simply put the whole idea into the 'too hard' basket.

Jan 1, 1995

By C Verdel, M Lee, A Oorloff, K Welsh

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Thomson Orogen is a large but poorly understood element of Queensland geology. Extensive cover conceals the Thomson Orogen at depth, thus limiting studies to a small number of surface exposures. Previous studies of the northern Thomson Orogen have been restricted to the largest of these exposures in the Anakie Inlier and Charters Towers Province. Less extensive exposures, including Mt McLaren in east-central Queensland, are largely overlooked and poorly documented. Fieldwork suggests that Mt McLaren is a west-tilted fault block of Thomson Orogen metasediments that are at least 2200 m thick. The substantial thickness of these sediments (which we have named the Mt McLaren Formation) and the consistent shallow marine facies throughout the block suggest deposition in an actively subsiding basin. Initial dating of detrital zircons places deposition of the Mt McLaren Formation in the Late Cambrian to Early Ordovician, allowing correlations with formations of similar composition and age in the nearby Anakie Inlier and Charters Towers Province. Both of these areas have a long history of mining and exploration for gold and base metals, suggesting that correlation of basement sequences across these areas could be beneficial for exploration models of the Thomson Orogen as well as for tectonic models of eastern Australia.CITATION:Lee, M, Verdel, C, Welsh, K and Oorloff, A, 2015. Stratigraphy of the Thomson Orogen – new insights from Mount McLaren, north-east Australia , in Proceedings PACRIM 2015 Congress, pp 551–556 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By R Adofo

Underpinning the mining process is a continuum of prediction, specifically of tonnes, grade and recovery from exploration to grade control, through short-term mine design, to mining and processing. The interdependence of one activity on the other is so strong that it can be difficult to partition the activities and determine where there are issues, if any. Reconciliation is the process that compares the predictions of the various estimates to the actual product produced at the end of the production chain. Quite often, an attempt to understand the variances from one measuring point to the other creates a ‘wicked problem’.This study outlines the benefits of incorporating the principles of ‘systems thinking’ into the mining reconciliation process, by constructing a framework within which reconciliation is effectively managed. The philosophical base for any variances between successive links in the reconciliation chain cannot be attributed purely to the statistical variance between the predicted and the actual grades achieved, but should include the interrelationships between the technical and managerial professionals involved. Systems thinking, as an interdisciplinary approach, draws its ideas and concepts from a variety of disciplines, and in so doing can exploit their different strengths.The study described in this paper offers methodologies to analyse the task, in advance of developing a technical solution. Two systems thinking methodologies, Grounded Theory (GT) and Soft Systems Methodology (SSM) were employed. These methodologies, are geared towards dealing with relationships and interactions between individual parts and the whole. The GT coding in the study specified that the key activity that would drive the reconciliation process is through an effective reconciliation meeting, and the competencies of a ‘reconciliation team member’ This team member should be a good communicator and enjoy challenges, be open-minded and transparent, and have a broad perspective of the mining process and relationships across the different activities.CITATION:Adofo, R, 2017. A systemic approach to managing the Mine to Mill reconciliation process, in Proceedings Tenth International Mining Geology Conference 2017, pp 95–102 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

By C A. Fleming

Gold extraction is largely driven by mineralogical factors, which often cause gold losses to various tailings. Mineralogical factors affecting gold recovery include grain size and shape, surface coating or rimming on gold particles, the presence of cyanide or oxygen-consuming minerals or preg-robbers, the presence of slow-dissolving gold minerals and the refractory nature of submicroscopic gold. Among these factors, locking of fine gold particles in sulfide, silicate and other minerals, either as visible, fine-grained gold inclusions and/or as invisible submicroscopic gold, is by far the most common factor leading to poor gold recovery in gold ore processing. This paper discusses the mineralogical characterisation of gold lost in tailings and its metallurgical implications. The techniques used in characterising the un-recovered gold are also briefly introduced.

Jan 1, 2007

There is an alternative theory of the high grade orebodies of the Middleback Group, based on the primary nature of the high grade ores in an area of carbonate deposition, with lesser amounts of siliceous and aluminous sediments. The environment is thought to have been unstable, possibly volcanic, and to have been a subsiding basin, substantially isolated from the open sea.Jaspilites, iron bearing talc rocks and iron bearing carbonate rocks were derived from the primary sediments by metasomatic alteration after metamorphism.The metasomatic agents were carbon dioxide and water vapour which were mobilized from the primary dolomite and reacted with a metamorphically produced group of iron bearing and iron free amphiboles, forming talc and progressively releasing silica and iron oxides from the iron amphiboles.The talc rocks in turn released silica which reconstituted jaspilites into their present 200 ft thick crust or zone.The theory accounts for the present disposition of a jaspilite zone over a talc zone which in turn overlies a carbonate zone, and accounts for the down dip changes found in bores which penetrate these zones.INTRODUCTIONIron Duke (Fig. 1) lies some 34 miles south west of WhyalIa in South Australia, and is the most southerly ore body in the Middleback Ranges.The Middleback Ranges are divided into a northern range and a southern range meridionally disposed and separated by an erosion gap called Kimba Gap.The South Middleback Range contains four orebodies;Iron Duke at the southern extremity, Iron Duchess north of Iron Duke and on the same ridge, Iron Knight also on the same ridge, which has been breached by erosion between theDuchess and Knight orebodies, and north east of Iron Knight, the Iron Chieftain.Cook's Range is the eastern range of the South Middleback Range and no large orebodies are known to occur there.

Jan 1, 1963

A genesis based on new developments in the physical chemistry and flow properties of colloidal substances is proposed for the pipe-like Peko orebody. The rheological behaviour of sediments is governed by the contained colloids. Remobilization of thick pasty sediment during diagenesis is regarded as an essential step in the concentration of metal dispersed in sediments. At a high concentration the sediment pore fluid is a dense gelloid such that van der Waals attractive forces between the colloidal particles exceeds the coulombic repulsion. This permits accretion of the colloids into globular clots and their fracture fragments. These have a uniform size distribution dependent upon the rate of shear, and the sediment lithifies to clotted, porphyry-like, "gritty", dolomitic or igneous-looking intrusions and flows. The physical chemical properties of natural sediment colloids appear adequate to account for ore formation.Adsorption accounts for the dispersion and retention of metal in sediments. Accretion accounts for the segregation of the colloidal materials to give the various types of clotted igneous-looking intrusive source rocks. Syneresis enables the colloids to spontaneously draw together and to dehydrate. Formation of an ordered lattice achieves a lower energy state and desorbs metals and insoluble metal compounds "particle by particle" into the escaping water of hydration and pore water. Peptization enables migration of the metal hydrosols as stable dispersions until they merge for outflow through seepage zones or water extrusion channels. Nucleation and concretion precipitate the metal dispersoids from pore waters seeping through hydrous parts of the source rock, porous beds, faults, and zones of weakness by which the connate waters leave the lithifying sediments. Gelatinous precipitated mineral matter in the ore channels is capable of thixotropic reliquefaction when disturbed by shock or movement. Local reintrusion, flowage, interveinings,brecciation, and intermixing of the materials is the result.The principles of the suggested genesis are applicable to both syngenetic and epigenetic mineral accumulations.

Jan 1, 1966

Study on Mineral Processing of Refractory Copper-Nickel Ore

Sep 13, 2010

Great new drilling results! What's so sinful about being a multi-national company? Overseas protestors flown to Australia for a free holiday How to counter the protectionist danger? Our current economic standing Over-regulation puts a convicted paedophile on the payroll The broken window fallacy Mining - A shared history Aristotle and the camels A brighter future? Something over which we do have far greater control, i.e. leadership within our own industry My challenge to you The expanding gold- producing company of which I am proud to be Chairman, Croesus Mining NL, is by definition a æmultinationalÆ. Our shareholders are based in 36 different countries, 77% of our 107 million shares are held in Australia, 23% are held outside Australia, and include New Zealand holdings of 7%. In September, Croesus Mining presented our company at the Mining 2000 Forum in Melbourne, a city caught up with multinational protestors demonstrating against multi-national companies.  

Jan 1, 2000

The Canada Centre for Remote Sensing (CCRS) has developed an airborne sensor, the SWIR Full Spectrum Imager (SFSI) which detects in the short wave infrared range of the solar spectrum from 1220 to 2420 nm. In June of 1995, a demonstration flight was undertaken in the state of Nevada with the support of the companies listed above. The focus of the flight was to collect image data over well known mineral deposits with the objective of evaluating the applicability of this sensor to alteration mineral mapping. Some of the Nevada sites chosen include Cuprite and Goldfield, volcanic hosted acid sulfate systems; Yerington, a structurally complex porphyry copper deposit; and Virginia City, a quartz-sericite-pyrite vein system with advanced argillic pods. Ground spectral data was collected with the PIMA-II spectrometer. Solar reflectance calibration was done by Desert Research Institute personnel at Virginia City and Cuprite. This paper will discuss the configuration of the sensor and present image and ground data for Goldfield and Virginia City.

Jan 1, 1995

By A J. Scogings, W J. Shaw

The successful development of industrial minerals projects requires an integrated, holistic understanding of the metallurgical and product performance test work in the context of the geological setting of the deposit and applied to mining, processing and marketing of saleable products. The product specifications provide the essential starting point for geometallurgical studies. A sound understanding of the desired product is needed to design and interpret a program of test work. Examples are provided from recent studies on bentonite and graphite deposits.For bentonite projects, the naïve testing of only the cation exchange capacity (CEC) as a measure of purity can lead to unexpected outcomes when the deposit is mined. The CEC attribute may remain the same, while other important properties such as pH and swelling index change markedly with depth, due to weathering and oxidation, leading to disappointing production outcomes.For graphite projects it is not enough to report only total graphitic carbon content (TGC). Knowledge is required of the in situ flake size and textures in addition to purity and flake size distribution of extracted graphite, which may all vary from one domain to another across the deposit. Such geometallurgical attributes of the ore will impact on the ‘basket price’ used to estimate the value of marketable parcels of expected product.Disclosure of such information must be considered part of fully informing the market. As with all new project developments, consideration of the JORC (2012) and VALMIN (2015) Codes requires disclosure of all material information. This includes the geometallurgical characterisation, ie those aspects of the mineralogy that impact on resource evaluation, ore reserve definition and project valuation.CITATION:Shaw, W J and Scogings, A J, 2017. The importance of geometallurgical test work for industrial minerals projects, in Proceedings Tenth International Mining Geology Conference 2017, pp 83–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017