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By K H. Esbensen, K Engström

The conclusion from the debate over the last decade in the mining sector is that, for grade control, reverse circulation (RC) drill sampling gives more reliable results due to less sampling problems than blasthole samples. However, by conducting the latter with well-controlled procedures there still exist fair possibilities to counteract the major blasthole sampling problems and achieve fit-for-purpose representativeness, especially if based on minimal loss of fines. In the present PhD study, extensive replicate experiments and variographic characterisations are conducted to evaluate the performance of manual blasthole (BH) sampling and sectorial segment sampling. The experiments were performed in Luossavaara-Kiirunavaara AB (LKAB)’s Leveäniemi open pit mine in the north of Sweden. The experimental area is an apatite-magnetite iron ore deposit of the Kiruna type, with the demand to exhibit a maximum of local heterogeneity to allow the experiment the largest possible conclusion powers. Gathering and splitting the complete BH drill cutting cones (fines cone, coarse cone) served as an authoritative reference on which to assess the representativity of the two BH sampling methods.Results show that manual BH drill sampling is able to produce samples with an acceptable accuracy and precision if performed properly and with insight. Based on variographic comparison, segment sampling shows similar precision for chemical grades as the manual sampling, while the particle size distributions were more deviating for segment sampling than for manual sampling at the high and low size ranges. Possible reasons for these partly surprising results are discussed.For further investigation of the performance of BH versus RC drill sampling, a second experiment has been planned on a parallel profile. This will result in an unprecedented opportunity for a full variographic comparison between RC and BH sampling, aimed at designing specific, fit-for-purpose sampling procedures as a function of ore quality, cut-off grades and important contaminant levels.CITATION:Engström, K and Esbensen, K H, 2017. Blasthole sampling (replicate and variographic experiments) in LKAB open pit iron ore mines – fit-for-purpose representativity?, Australia, in Proceedings Eighth World Conference on Sampling and Blending , pp 85–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By C T. Hollick

Conventional processing of heavy mineral deposits containing radioactive rare earth minerals such as monazite and xenotime may cause industrial hygiene problems through atmospheric dust and contamination of product concentrates. An alternative procedure has been developed in which such minerals are removed from bulk heavy mineral concentrates by flotation with little loss of other economic minerals. With fine ores, recoveries of over 95 per cent have been achieved and with coarse ores over 80 per cent, in both cases at high grade. Several flotation regimes have proven effective. The potential for generation of radioactive dust or product contamination is subsequent processing is correspondingly reduced.

Jan 1, 1990

Study on Mechanism of Sphalerite Flotation in the Presence of Main Metal Ions by Molecular Mechanics

Sep 13, 2010

Hatches Creek has been inactive since 1961, but with better metal prices, interest in the field is reviving.The mixed gravity concentrates which were unsalable in 1951 have been experimentally separated into salable wolfram, scheelite, and bismuth-gold concentrates, and a flow sheet incorporating magneticseparation and flotation has been developed.

Jan 1, 1965

The GPS and information technology industries are now applying considerable development effort to what is being termed machine control and machine information systems, in particular focusing on the industries the of mining construction and agriculture. GPS based systems are demonstrably finding common acceptance and adding commercial value to many machine applications in industry. This has been the first step in the evolution of the information age that is now reforming mining practices. Adding the technologies of wireless data communication, modem computer databases, and networked PC's mining is on the verge of a new era in overall process management. This paper is a general discussion of what the information age means to miners and a general description of new mining operation technologies available to day from the Caterpillar technology alliance.

Jan 1, 1999

Mineral Processing Engineering Education in China - Bringing up the Engineering Diathesis and Design Competence of the College Students

Sep 13, 2010

The problems of using comparatively simple x-ray diffraction equipment for quantitative analysis are examined. Internal standard and direct calibration procedures based upon the measurement of integrated diffraction energy (diffractometer peak area) have been developed for the determination of quartz in Broken Hill dusts. By these methods an accuracy of ± 10 per cent of the true value can be obtained and this can be improved to ±2 1/2 per cent by statistical methods if necessary.Rapid analysis for the components quartz, muscovite, rhodonite, galena, fluorite, sphalerite, calcite, and garnet has been developed by adaptation of direct calibration procedures and use of maximum diffraction energies (diffractometer peak height). Until more is know!) about the pathological effects of multi-component dusts of the Broken Hill type it seems undesirable to fix theIr allowable concentrations in terms of the quartz content.

Jan 1, 1968

By the use of flotation tests it was confirmed that there are two functions of oxygen in sulphide mineral flotation. Sized samples of galena and chalcopyrite were sulphidized, washed free of excess sulphide ion, and then contacted with air-saturated water for certain lengths of time. The mineral was then transferred to a sealed laboratory flotation cell containing water with a known concentration of dissolved oxygen. Xanthate and frother were added and flotation continued for 1 min.Both the extent of mineral oxidation and the concentration of dissolved oxygen markedly affected the flotation of galena and chalcopyrite. The response to a change in either variable is dependent on the level of the other, but generally best flotation occurs with the maximum degree of air saturation of the pulp. Galena flotation is hindered by oxidation of the mineral beyond a small threshold amount but a similar effect for chalcopyrite was not observed...

Jan 1, 1967

Esso-BHP have installed a production supervisory control system that is presently controlling the offshore oil and gas facilities on the Barracouta and Marlin platforms from an onshore master station. This control is achieved with a computerized master station onshore which uses a UHF radio system for telemetry and control.The system is designed to control, monitor, and gather data from a large number of oil and gas production platforms and has flexibility to handle future variations in operating conditions.The system will be extended to the Halibut platform late in 1970 and to the Kirlgfish platforms during 1971.

Jan 1, 1971

By Moresby J. F

Segregation roasting was used to recover more than 85 per cent of copper from crushed, minus 14 mesh refractory furnace-lining bricks. A plus 14 mesh fraction: which was high in copper, could be recycled directly to the smelter, giving an overall recovery of approximately 90 per cent. An oxidation roast at about 700°C was necessary, before segregation roasting, to convert copper sulphides and copper metal to sulphates and oxides. Withsegregatron temperatures in the range 600°-650°C the quantities of solid carbon and NaCI required are 2-5 per cent and 1 per cent respectively. P.V.C. coating from scrap copper wire can be used instead of NaCl as asource of hydrogen chloride for the segregation reaction.

Jan 1, 1978

By Lawrie D. C

Finely ground beryl was decomposed by mixing with ground limestone and soda ash and heating at 900°C for 4-6 hr. The sintered mater:al was then crushed and leached by boiling under reflux with 5N sulphuric acid for up to 4 hr. The liquor containing Be, AI, Fe and other elements as sulphates, was separated from the residue which consisted mainly of silica and gypsum, either by filtration or bydecantation washing.The clarified leach liquor was first treated to remove Fe+++ by contacting with a primary amine-kerosene solution in 2 countercurrent stages. The iron free liquor was then passed to a 4-stage counter-current extraction unit where it was contacted with O·5M di- (2 ethyl hexyl) phosphoric acid (EHPA) in kerosene. Under the operating conditions, 99 per cent of the Be and 7 per cent of the Al was extracted.The Be and Al were stripped from the organic phase by sodium hydroxide solution of suitable concentration to form soluble "beryllate" and "aluminate" respectively. Most of the Be was subsequently precipitatedas Be(OH)2 by heating the alkaline solution to 90°C, the Al remaining in solution. After filtration and washing, the Be(OH)2 could be ignited directly to BeO at about 1000°C or used as a feed to further purification stages if required.A small counter-current extraction unit was operated continuously using liquor derived from the sintering and leaching stages. Dataobtained in batch laboratory tests were confirmed. A product obtained by ignition of the washed "beryllate" precipitate contained more than 99 per cent BeO.INTRODUCTIONIn 1958 an investigation was commenced into the recovery of beryllium oxide from beryl, as part of a programme to utilize mineral resources of South Australia. A survey of the literature indicated that little work had been done on direct solvent extraction of beryllium from aqueous liquors, so it was decided to apply the experience gained in this field in uranium processing to the current problem.Preliminary extraction tests on solutions of beryllium...

Jan 1, 1965

By D N. B Skinner

Changes in the configuration of late Cenozoic volcanic arcs related to Pacific-Australian plate convergence in northern New Zealand may have localised large-scale epithermal gold-silver mineralisation to a particular part of the volcanic arc system, the Coromandel Volcanic Zone (CVZ). The history of arc-type volcanism in northern New Zealand began with the development of the continental margin Northland Volcanic Arc from early-mid Miocene (26-15 Ma). From 18-15 Ma the Northland Volcanic Arc extended south into the northern and western part of the CVZ where it is dominantly composed of andesite with lesser dacite and very minor rhyodacite. In the south, centre and east of the CVZ, younger andesite-dacite volcanism overlapped in space and time (14-5 Ma) with voluminous rhyolitic volcanism associated with rift-hosted calderas and minor basaltic eruptions. This change to bimodal rhyolitic-basaltic volcanism and extensional tectonics was a result of southwest (SW)-directed propagation of the Colville-Lau oceanic island+ arc into the north-northwest (NNW) trending Northland Volcanic Arc and its underlying continental crust. The extensional tectonic regime created in the collision zone between the two arcs is also the site of the 14-6 Ma Coromandel epithermal gold-silver province, which contains some 50 separate deposits and has a production (1862-1996) of about 300 t Au and 1150 t Ag. Extensional tectonics facilitated the emplacement of silicic magma at shallow crustal level and led to reactivation of deep basement faults. The resulting enhanced heat flow and fault-focused fluid flow localised large hydrothermal systems and associated extensive low-sulphidation epithermal gold-silver deposits in the southern part of the province, as at Waihi, Golden Cross and Karangahake.

Jan 1, 1997

By King E. J

Department of Pathology, British Post-graduate Medical School, London:The experiments here recorded were devised and carried -out during the last two years in an attempt to corroborate the important work of Denny, Robson and Irwin (1939) in which they found that experimental silicosis could be prevented by means of metallic aluminum. By causing rabbits to inhale powdered quartz for several months they induced experimental silicosis. These animals then served as controls for comparison with another group which were dusted with a mixture of quartz and aluminum. In the second group silicosis failed to develop.Our experimental procedure was somewhat different. We resorted to intratracheal insufflation instead of simple inhalation, and we used rats instead of rabbits: otherwise the essential features of the original experiments were carefully duplicated.EXPERIMENTAL PROCEDURES.A single dose of dust was delivered into the lungs of each animal. The dust was suspended in a fluid medium and injected by means of a syringe directly into the trachea in known quantity (technique of Kettle and Hilton, 1932). The suspensions were autoclaved before use and were injected with aseptic precautions. Having had a long experience of this technique we employed it with confidence and usually secured a fairly uniform dispersal of dust throughout both lungs. To carry out injections successfully one requires, above all, an even suspension of dust which will flow smoothly and quickly from the syringe. This is not difficult in the case of quartz, for, though it tends to settle out rather quickly, this can be avoided by constantly agitating the suspension. The syringe containing the inoculum may be shaken gently right up to the moment of injection and then emptied quickly to prevent sedimentation. Powdered aluminum is more difficult to handle, for the particles tend to flocculate and are not readily made to disperse evenly in saline, even by violent shaking. For this reason an emulsifying agent may be used to advantage, provided it does not complicate the experiment, a point to be mentioned again presently.THE EXPERIMENTSExperiments with quartz alone: Extensive silicotic lesions were produced in 23 out of 26 rats by the administration of pure quartz dust in doses of from 50 to 200 mg. per rat. The dust was so finely pulverised that the particles averaged about 1-p. in size: none was larger than 5 p. and 99 per cent. were under 2.5 p.Eight of these animals survived for seven months and were then killed...

Jan 1, 1945

Tumbling mills and some theoretical and practical aspects of milling are discussed. Attention is directed towards the difficulty of relating the dynamical analyses of the motions of particles within mills to the existing treatments of breakage processes. This synthesis may be advanced by a study of milling that utilizes the matrix analysis of breakage processes. Application of the matrix analysis to results obtained on (i) grinding in open-circuit a zinc ore in a conical pebble mill and in a modified conical mill, (ii) "grinding of cement clinker in a compound mill, and (iii) to some drop-weight grindability tests is discussed. It is shown that the 'IT-breakage model adequately describes the breakage processes of each of the tests. (The proportion broken in each breakage cycle is given by 'IT and is independent of particle size.)The size distributions of the products are accurately predicted in the cases considered. Matrix analyses of the breakage of coals, various ores and a cement clinker have been made. Appendices give an elementary account of the matrix methods and give the equations fully describing reverse order closed circuit operations. The matrix analyses of breakage processes and the survey are used to examine briefly closed circuit grinding.INTRODUCTIONTumbling mills are slow-speed crushing and grinding machines which have been developed from some fairly simple types into many widely differing forms. Many of these versatile mills have proved extremely useful in ore dressing and mineral beneficiation, whereas others have been used in the cement industry and less extensively in the coal industry.The performance of even the simplest tumbling mill is very imperfectly understood, whilst the more difficult problems associated with the balancing of complex milling circuits and with the establishment of the optimum operating conditions for the whole of a complex circuit are even less well apprehended.Our knowledge of the performance of tumbling mills is rather sharply divided into two categories: the first consists...

Jan 1, 1957

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

By E Villaescusa, C Drover

Fully resin encapsulated threaded bar and cement grouted cable bolts are common forms of reinforcement for underground mining excavations constructed at great depth. These elements are frequently installed to dissipate the dynamic loads caused by violent rock mass failure mechanisms. Failure of the ground support scheme without rupture of the reinforcement elements implies that the maximum energy dissipation capacity of the scheme was not utilised. The ground support damage mechanisms are useful to identify in this context as they reveal vulnerabilities which limit the scheme performance. This paper presents a number of field observations of reinforcement performance following a range of dynamic loading conditions. It was observed that fully resin encapsulated threaded bars exhibit variable behaviour. In particular, inconsistent resin encapsulation was frequently observed in combination with surface support failure, indicating that the retention function of these elements may allow preferential loading of the surface support system. Observations of cement grouted, twin-strand plain cable bolts reveal a common mode of damage involving differential displacement across the steel-grout interface and slip of the cable within the borehole. This is common where strands are not mutually tensioned with barrel and wedge assemblies. Surface fixtures that exceed the strength capacity of the cable strand are required in order to minimise the occurrence of this response. Improved load transfer from the rock mass and surface support to the cable can thus be achieved, particularly where small block size failure occurs.CITATION:Drover, C and Villaescusa, E, 2016. Field performance of fully encapsulated reinforcement during violent failure events, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 659–668 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

THE Great Cobar Company Limited owns 1100 acres of freehold, which include the Great Cobar Oopper Mine and smelters, the Cobar Gold Mine, the Cobar-Ohesney Copper Mine, and the Great Peak Gold Mines.ORE OCCURRENCEThe ore-bodies in the first three mines-namely, Great Cobar Copper Mine, Cobar Gold Mine, and Cobar-Ohesney Oopper Mine are, speaking generally, lenticular deposits of evidently more or less complete metasomatic replacements of the country rock along a line of powerful faulting. These lenses vary from 150 ft. to 400 ft. in length, and from 20 ft. to 100 ft. in width.

Jan 1, 1919

The Porgera gold deposit is an epithermal gold base-metal deposit located in the Enga Province of Papua New Guinea. Gold-silver-sphalerite-galena-pyrite mineralisation is related to stocks and dykes of dioritic composition which have intruded a series of folded marine sediments, mainly shales and siltstones, often with calcareous and carbonaceous horizons, of middle Jurassic to middle Eocene age. The most intensely mineralised zone is at Waruwari Hill, where the mineralisation occurs predominantly as massive mixed sulphide veins, and less frequently as quartz-chlorite veins and as disseminations. Mineralisation occurs in all rock types and several phases of mineralisation have been recognised.

Jan 1, 1980

Individual specimens of sphalerite from the Broken Hill lode vary considerably in manganese and iron contents, even within the same orebody, so that study of the overall variation of manganese and iron content of the sphalerite calls for the analysis of a large number of specimens. This difficulty has been overcome by analysing a series of recleaned zinc concentrate products, prepared from stope samples and their equivalents, from most of the developed sections of the lode. The analyses reveal that during the formation of the sphalerite the concentrations of iron, manganese and zinc in the mineralizing solutions varied independently of one another from place to place in the forming orebodies, and also in time.The overall pattern of variation of the iron and manganese contents of the sphalerite in the several orebodies of the lode bears a general resemblance to the overall pattern of distribution shown by several other elements, notably, cadmium, lead, bismuth and arsenic. The iron content of the sphalerite indicates that it was formed at a temperature of 6000 C. or higher, but the variation in its iron and manganese contents demonstrates that Kullerud's method for determining the temperature of formation of sphalerite from its iron content must be used with caution if only single specimens of sphalerite are available.INTRODUCTIONThe four chemical analyses available of specimens of practically pure sphalerite from the Broken Hill lode (Table 1) reveal that the manganese content of the sphalerite varies considerably, and that there is a significant variation in its iron content. The variations revealed between individual specimens within the same orebody in the same mine suggest that specimen material is unsatisfactory as a basis for studying the overall manganese and iron contents of Broken Hill sphalerite, unless a great number of specimensis analysed.

Jan 1, 1956

Iron Ore - Mineral Processing Overview Several years of iron ore price increases, coupled with a period of strong global demand for raw materials, presented iron and steel producers with unprecedented costs and difficulty procuring the demanded high quantities of iron ore. These conditions spurred many companies to investigate new ore bodies and also reassess past decisions (such as divestment of captive iron ore mines that ensured dedicated supply or a move to reliance on the 'spot market' instead of long term contracts with suppliers) and revisit alternative sources of iron units, including low grade deposits, tailings reprocessing, Ti-rich ores, and iron sands. To properly upgrade these iron sources requires a complete battery of mineral processing techniques. Within different regions around the world, operations and technology have developed to specifically beneficiate the local ore bodies. This paper attempts to bring these different general processing techniques together to allow insight into various common and proven methods of iron ore beneficiation. This paper further explores the current trend to develop global iron ore reserves, and discusses the methods to beneficiate and successfully reduce and smelt iron ore using Outotec's physical separation, direct reduction and smelting technologies for final production of pig iron and slag. Use of these various technologies may allow treatment of what was typically considered a tailings stream into a profitable product.

Sep 13, 2010