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By Both R. A, Daily B

The Patawarta Diapir, located in the northern Flinders Ranges (South Australia), has intruded into late Proterozoic Wilpena Group sedimentary rocks. The diapir contains disrupted blocks of a wide variety of rock types, most of which can be correlated with the Lower Callanna Beds of Willouran age, in a matrix of predominantly carbonate and siltstone breccia. Mafic rocks in the diapir appear to predate intrusion of the diapir. As with many other diapirs in the Flinders Ranges, copper mineralization is present in the diapir and occurs as narrow veins consisting essentially of carbonate with chalcopyrite and pyrite that formed after diapiric intrusion.Fluid inclusion studies demonstrate that the mineralizing fluid was a Na-Ca-K-Cl brine; probably derived by expulsion of interstitial water following emplacement of the diapir, with dissolution of evaporites within the Callanna Beds sediments and enrichment in copper by reaction with these sediments and associated basic igneous rocks. Mineral assemblages combined with fluid inclusion and geochemical data indicate a possible environment of vein formation of T ÿ 165°C, pH ÿ 4.3 ± 0.9 and log fO2 ÿ -47.3 ± 0.5. Sulphur isotope analyses indicate d34Sfluid ÿ 10 per mil, suggesting evaporites in the Proterozoic sediments as the major source of the sulphur but with some additional sulphur from an igneous source, possibly leached from the malic rocks of the diapir.

Jan 1, 1986

By M Grigorescu, S Crimp, J H. Hodgkinson, P Kokic, W Jin

Mines are typically located in remote, inhospitable locations and movement of materials between site, processor and port are often at risk from extreme weather events. Mining companies have recorded multiple supply chain, production and logistics delays caused by climatic events. Recent analyses of extreme temperature and rainfall events (90th and 99th percentile values) for 1960 to 1985 and 1986 highlighted regionalised increases in the frequency and intensity of extremes. The trajectory of this change is likely to be maintained (IPCC, 2014) in regions where increases have occurred historically, suggesting that some parts of the industry may be faced with management challenges beyond current experience (Hodgkinson et al, 2010; Loechel, Hodgkinson and Moffat, 2012). Reliance on historical data to plan for extremes (such as scheduling production downtime to reduce impact) will become increasingly ineffective as the data become less representative of future conditions. Importantly, mine site remediation and closure management need to consider the future climate to ensure rehabilitation is sustainable under changing conditions.Vulnerability assessments and risk-reducing adaptation will become more common as the industry reaches to secure both a mine’s longevity and the industry’s reputation as shareholders and clients become less tolerant of repeated or prolonged interruptions (Hodgkinson, Hobday and Pinkard, 2014). Climate-resilient new mines may be planned using site planning tools combined with knowledge of future climate scenarios. Scenario tools are valuable for developing a gated risk management approach to reducing climate-risk during a mine’s life, through to the rehabilitation process and for managing care and maintenance or closed mines.CITATION:Hodgkinson, J H, Crimp, S, Jin, W, Kokic, P and Grigorescu, M, 2016. Life-of-mine planning tools for a changing climate – intuitive, interrogative, iterative, in Proceedings Life-of-Mine 2016 Conference, pp 71–74 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By B Hooper

Deep cuts in CO2 emissions will be required to stabilise and, in the long term, decrease CO2 concentrations in the atmosphere. Technologies for capturing CO2 from major stationary sources (power stations, industrial plants, etc) and storing that CO2 for long periods of time is one of few near term options for decreasing CO2 emissions. This transition to low carbon intensity energy and possibly the hydrogen economy through renewables and in the long-term technological developments such as artificial photosynthesis.Capture of CO2 from post combustion emissions can be done using a range of technologies though costs are currently high and dependent on the concentration of CO2 in the emissions. Techniques include solvents, pressure swing adsorption and the use of membranes. Options for decreasing capture costs by increasing the concentration of CO2 in the emission stream include the use of oxyfuels (in pulverized fuel types boilers) and by moving to integrated gasification combined cycle (IGCC) operations either simply for power generation or for poly-generation opportunities. Once the CO2 has been captured it can be stored using a variety of methods. Storage in the ocean has been suggested but is considered an unlikely option because of environmental uncertainties and political opposition. Mineral storage is a niche opportunity. The greatest potential lies in geological storage of CO2 and this option is commanding increased attention from the Australian and international community.In Australia, the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) is an important new initiative that will support energy companies and energy intensive industries in meeting challenges posed by greenhouse gas issues and assist them in their efforts to reduce their emissions profile.The progress of geo-sequestration and the challenges in the capture and separation of CO2 in the process industries are discussed.

Jan 1, 2004

By E N. Isaev, L E. Levin

New data on the geology of the Late Jurassic to Holocene sediments cover of the World and associated mineral resources (oil, gas, ferromanganese nodules, ores of massive sulphides and other metals) have been compilled in the Atlas at scale 1:25,000,000 and 1:10,000,000. The work was performed by scientists from four Institutes of Russia (VNIIzarubezhgeologia, VNIIoceangeologia, Vernadsky Institute of Geochemistry and Analytical Chemistry of theRussian Academy of Sciences and Geological Institute of the Russian Academy of Sciences). The Atlas shows variation of thickness and formational composition of the large complexes (Upper Jurassic-Early Cretaceous, Upper Cretaceous Eocene, Oligocene-Neogene, Pliocene-Pleistocene), distribution of oil/gas and ore deposits in each complex, data of deepsea drilling (leg 1-130),  thermo-pressure condition in the sedimentary basins within Circum-Pacific Rim.

Jan 1, 1995

Longwall mining has historically been considered an application for only deep reserves. This has changed in the recent past as longwall has become competitive with surface mining. Many resources marked for stripping now he in the domain of longwall. Today, the best longwall mines compete with strip mines operating in even the lowest stripping ratios. Longwall mining has become more widely applicable than it ever has been in the past and it is now generally considered the method of choice in situations where high levels of coal production are required. But the best way to use longwall mining has become less certain with the opportunities that highwall access provides. Wall-to-wall mining is the use of retreating longwall developed from and retreating toward a highwall. As a surface mine reaches its ultimate highwall, the opportunity for longwall punch mining or wall-to-wall mining is obvious. There are several clear operating advantages to operating a longwall in this way and where highwalls are available, the best economic decision will generally favor planning a direct approach. Yet wall-to-wall is not applicable in every situation even when highwalls are available. Moreover, the advantages of wall-to-wall mining do not always justify the cost of trenching or box cuts to access coal . However, many tactical advantages of operating from the highwall can be realized with the use of specially equipped blind drilled or raised bored shafts. This paper discusses novel techniques for a shaft assisted mining system which permits the addition of conveyor structure and mine systems from the surface to the face for advance and retreat mining with longwall, shortwall or room and pillar panels.

Jan 1, 1998

By Somasundaran P

Controlled modification of mineral/liquid interfacial properties by adsorption is critical for mineral processing operations such as flotation, filtration, dispersion and flocculation. Ionic/nonionic surfactant mixtures usually show enhanced surface activity and salt tolerance over ionic surfactants, and this is especially beneficial for flotation of salt type minerals in which case dissolved multivalent cations in high concentrations usually cause loss of anionic surfactants by precipitation. Adsorption of nonionic/anionic surfactant mixtures on kaolinite has been studied with sodium dodecylsulfate as the anionic surfactant and octaethyleneglycol mono-n-dodecylether as the nonionic surfactant. Synergistic interaction between these surfactants was found to cause adsorption of the nonionic surfactant with its hydrophilic chains protruding into the bulk, leading to substantial changes in flotability and dispersion characteristics of kaolinite. Similarly, hydrophobicity changes are observed also' for silica particles upon adsorption of nonionic ethoxylated alcohols owing to possible changes in the orientation of the adsorbed surfactant species at the interface. Also, based on the results obtained with surfactant adsorption, a hydrophobically modified polymer was used successfully to disperse graphite particles in aqueous solution.

Jan 1, 1993

By Fairhurst RM

High pressure abrasive water jets have been shown capable of cutting a wide range of materials including steel, stone, rock and concrete. Acceptable performance can be achieved using relatively low pressures and expendable abrasives. The cutting head can be made small and abrasive feed systems have been developed that allow reliable pumping of slurries over long distances to supply such cutting heads. These features make abrasive water jets ideally suited to automated control in remote areas.Another major advantage of abrasive entraining water jet cutting heads is that they may be operated safely in potentially explosive environments due to their cold cutting ability. Therefore there are many possible applications for such equipment in mining.This paper gives an introduction to the abrasive water jet process and includes results of trials carried out at BHRA on a range of hard materials. Work is also described which investigated the operational safety of abrasive water jets in explosive environ-ments. In a special environmental chamber, cuts were made on steel and sandstone with atmospheres of methane/air and hydrogen/air, without caypsing ignition.

Jan 1, 1985

THE object that the writer has mainly in view in presenting this paper is to draw the attention of those connected with the technical side of the industry to the unsatisfactory and by no means up-to-date methods employed in estimating the tin contents of an ore. At the same time, what is regarded, from the writer's personal experience, as a satisfactory and reliable method is explained in detail. It is a curious fact that for the last 25 years tin·assay methods have made little or no advance, while those now in general use ill connection with copper and lead ores can scarcely be compared with those then obtaining, so greatly have they been improved upon. Though it. is not altogether expected that the method herein advocated will at once meet with general approval, the writer hopes the resultant discussion may bring out points that have hitherto escaped detection.FIRE METHODSThe old Cornish method of smelting with anthracite is now obsolete. The cyanide assay, although unreliable, is still much used because of its simplicity. In the Malaya many buyers of tin ores use the cyanide assay, the smelting being carried out generally in a benzine furnace. It is essential that the smelting with cyanide be performed at a low temperature. Even then, impurities, such as Sb2S3 and...

Jan 1, 1912

By Mackenzie W. R, Harding C. G

The Islamic Republic of Mauritania is a large country of over 1 000 000 square kilometres situated on the Atlantic coast of north-west Africa. It is bounded to the north by Western Sahara and Algeria, to the east by Mali, and to the south by Mali and Senegal. With the exception of a narrow strip in the south along the Senegal River valley, the country lies entirely within the Sahara. The north of the country is largely devoid of vegetation, and it is estimated that 90 per cent of the population of 2.1 million people live in the southern quarter of the country. From about the turn of the century, Mauritania was ruled by the French from Dakar in Senegal and, until 1960 when it obtained independence from the French, Mauritania did not have a capital. Today, the capital is Nouakchott, home to an estimated 600 000 Moors of mixed Arab, Berber and African descent. After independence in 1960, disputes over Spanish Sahara to the north led to a military coup in 1978 and it was not until 1991 that a democratic constitution was adopted. The new constitution declares Mauritania to be an `Islamic, African, and Arab Republic.' It provides for an executive president, elected for a six-year term, and for a bicameral legislature, consisting of a national assembly and a senate. The first presidential and legislative elections were held in 1992 under United Nations' supervision. Mauritania's economy is predominantly pastoral, and the country depends heavily on foreign aid. Its principal export industries are iron ore mining (about ten million tonnes per annum from mines near Fderik in the north) and fishing. Mines d'Or d'Akjoujt SA (MORAK), a company in which General Gold Resources NL (GGR) has 42.5 per cent equity, produces over 50 000 ounces of gold per annum, which represents the third largest export industry in the country.

Jan 1, 1996

The relationship between comminution testwork results and the milling circuit that is subsequently selected is not a direct one and frequently involves recourse to databases of past test results. This in itself reflects the lack of a systematic engineering approach in the design process. This paper reviews comminution tests for SAG mill design in an attempt to identify where the essential information comes from that will be used in mill selection. The conclusion is that results from traditional test methods, including obscure and little used procedures like the Mokken test, are more valuable from an engineering perspective than parameters for breakage rate based modelling. Suggestions are made on ways in which existing test procedures can be enhanced in order to generate parameters that can be directly related to characteristics of the milling circuit being designed.

Jan 1, 2002

By Y Peng, D J. Bradshaw, G Long

As copper reserves deepen, they are becoming increasingly less pure. Penalty elements such as arsenic, antimony and bismuth are occurring in increasing concentrations. Environmental issues with smelters are leading to increases in penalty rates for these elements such that some concentrates may become difficult to sell. Arsenic concentration in Rosebery copper concentrates during 2010 varied between 3000 and 8500 ppm. Arsenic levels above 5000 ppm can preclude import to some customer countries. Optical mineralogy has indicated that arsenic in Rosebery copper concentrates is most commonly associated with tennantite (Cu12As4S13) in solid solution with tetrahedrite (Cu12As4S13). In addition, silver reports to concentrate as freibergite (Cu12As4S13 ). A reduction in arsenic content will therefore lead to a concurrent reduction in the silver content.A literature review by Long, Peng and Bradshaw (2012) indicated that arsenic bearing minerals could be removed using potential controlled flotation. Some success in reducing the amount of arsenic had also been reported using either roasting or chemical depression using reagents such as lime and cyanide. Due to the location of the Rosebery concentrator adjacent to world heritage listed temperate rainforest, the use of a roaster or cyanide was immediately discounted. Lime is already used as a reagent in the Rosebery flow sheet, so could be considered as a potential arsenic depressant.In order to determine a method of separating out the high arsenic bearing minerals, two series of flotation tests were conducted. The first series investigated the effect of pulp potential on the recovery of copper, silver and arsenic minerals; a second series investigated the effect of pH, froth depth and regrind.CITATION:Long, G, Peng, Y and Bradshaw, D J, 2012. Production of a low arsenic copper concentrate at MMG Rosebery, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 347-354 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By A C. Edwards

The Mongol-Okhotsk belt consists of detached fragments of the Circum Pacific fold belt which have been trapped within the Mongol-Okhotsk fold belt. In its western part, the structures of the belt form an east-facing loop that is not connected with the other orogenic structures of Central Asia. In the eastern part of the belt (the Mongol-Okhotsk suture zone) the terranes form a zone between the Siberian craton to the north and the Bureya composite terrane to the south, that is linked with the Circum Pacific belt. The accretionary terranes, together with their Precambrian backstops, form a series of consistently-stacked, paired units that are bounded by northwest and north trending sinistral strike-slip faults. The ages of the rocks forming these accretionary complexes vary from Late Precambrian - Carboniferous in the west to Cambrian - Jurassic in the east. The terranes developed due to a progressive westward stacking of the accretionary complexes during the process of accretionary growth. The magmatic rocks young eastward indicating that migration of the magmatic front of the arc followed the eastward growth of the accretionary complexes. The accretionary terranes may be differentiated by their Paleozoic lithological assemblages. Only the Selemdzha, Niman, and Kerbi terranes located in the eastern part of the Mongol-Okhotsk suture zone contain significant amounts of black shale, and it is these terranes that host the bulk of the hardrock and placer gold mineralisation that is present within the suture zone. Gold mineralisation is present both as vein style and disseminated mineralisation within structural duplexes.

Jan 1, 1999

By Y Zha, J L. Walshe, A Ord, N J. Archibald

The purpose of this paper is to discuss the concept of Geodynamic Modelling as an exploration tool and to provide a specific example, namely, the Century Zinc deposit in Northern Queensland. Geodynamic Modelling is an attempt to become more quantitative in the way we develop exploration models. It is a systems approach to ore genesis which examines the complete four-dimensional mineralising system of interest, rather than individual site specific ore deposits. The goal is to establish a predictive capability that enables the explorer to predict grade, tonnage, mineralogy, alteration patterns and precise location of a potential orebody given a particular exploration model. The process consists of two well-defined stages: firstly, a æsoftÆ modelling stage where all available data on lithospheric architecture, geodynamic history, fluid chemistries, fluid flow mechanisms and mechanisms of metal transport and deposition are collected; and secondly, a æhardÆ modelling stage where the system is modelled using fully coupled deformationûfluid flow-thermal transport-chemical reaction computer codes. In the case of the Century Zinc Deposit we point to its existence on the boundary between two fundamental blocks of Proterozoic mantle lithosphere. This boundary has controlled Pb/Zn mineralisation in Northern Australia from the Proterozoic through into the Paleozoic. Detailed thermal, chemical, fluid flow, deformation modelling of the Century System points to an origin involving mixing of crustal oxidised fluids bearing zinc, with reduced fluids bearing H2S and CO2 from the lower crust or mantle. We use this modelling to define critical exploration criteria for another Century type of deposit.

Jan 1, 2000

By V N. Rudashevsky, N S. Rudashevsky

Characterisation of platinum-group element (PGE) deposits and their process products has many challenges for the process or applied mineralogist. It is now well established that the PGE distribution for such samples is variably divided between submicroscopic concentrations of PGE in sulfides, tellurides and related minerals occurring as discrete platinum-group minerals (PGM), of which there are a large number of species, many with partial replacement between the PGE and between anions. Each PGE deposit type requires a targeted approach but fundamentally, there are two general methodologies in vogue. One way is to make a large number of polished or polished thin sections for detailed scanning electron microscopy (SEM)/optical examination to determine the PGM distribution and their associations and grain sizes. The other is to make concentrates of representative crushed or processed samples, thus having fewer subsamples to examine. Our method of choice is to use hydroseparation (HS) for concentration. HS provides representative concentrates of sizes down to ~10 ¦m, not possible by other techniques. Various microbeam methods have been used for analysis of trace quantities of PGE (EPMA, micro-PIXE, SIMS and LAM-ICPMS). We prefer LAM-ICPMS (laser ablation microprobe û inductively coupled mass spectrometry) because of the relatively large analytical volume sampled, the ability to measure all the PGE, monitor up to 20 elements, together with detection levels in the tens to a few hundreds of ppb. We provide typical results derived in studies of stratiform PGE ores and tailings, and a massive Ni-Cu sulfide ore.

Jan 1, 2008

By Tanner A. C, Harraway D. H

Various circuits were tried at Mount Isa Mines during the period 1959 to 19G3 with the objective of improving the differential flotation of galena and sphalerite. Many benefits and disadvantages of the various circuits were revealed. An analysis' of ore characteristics and their effect on flotation was made -and resullted in the design of a proposed circuit which is currently in the process of installation.INTRODUCTIONSince 1936 when lead-zinc sulphide flotation commenced at Mount Isa, at least three types of ore have been encountered.Each ore has presented problems to flotation metallurgists.The three types of ore are,1. partially oxidized upper level sulphide ore,2. Black Star ore from the lower levels with its carbonaceous fraction, and3. Black Rock ore which is similar to 2, but more free milling.In retrospect a number of the metallurgical successes of the past were short lived. Often flowsheets or 0perating practices were designed to solve a single metallurgical problem associated with the current ore being treated. As the ore changed the problem would vanish and the method originally taken to counter the problem could become unnecessary or deleterious to the treatment of the new ore. The general lesson learnt from-the past-is-that thetreatment of Mount Isa lead-zinc ore involves a number of equally major problems...

Jan 1, 1963

The Coal Resources Survey commenced in 1974 as a search for Huntly Power Station coal, but soon developed into the most detailed regional coal search programme to be instituted in New Zealand. The program was initially conceived as geological in nature, but later included geotechnical, geohydrological, mining assessment, coal use, and environmental considerations in its investigations. The programme never undertook development work but has provided Government and the private sector with a sound basis for identifying development options. The discovery of large-scale coal resources in the Mokau, Waikato, and Taranaki regions and the lignite resources of Otago and Southland are a measure of the Survey's success. The directive by Government to phase out the NZCRS to a large extent coincides with the completion stage of the program. With most of the detailed regional study finished, it now remains to collate the data and publish summary reports at Coalfield and Coal Region level, in order to maximise the use and value of the data collected over the years.

Jan 1, 1987

By W J. Rankin, D R. Swinbourne

There are large tonnages of low-grade manganese ores in India fromwhich it is uneconomic to produce ferroalloys by conventionalsubmerged arc furnace smelting. A possible way to utilise these ores is to smelt them with carbon to produce pig iron and a manganese-rich slag, then to metallothermically reduce the molten slag to silicomanganese. Thermodynamic modelling of the metallothermic reduction stage using aluminium, silicon or aluminium-silicon alloy as the reductant at 1450¦C showed that an acceptable grade of silicomanganese could be produced. Manganese recoveries were predicted to be about 80 per cent. Heat balances indicated that silicothermic reduction may not produce enough heat to maintain reaction temperature. Small-scale laboratory experiments showed that the manganese grade of the alloys, and the manganese recoveries, were close to those predicted, but those for silicon were muchlower. Aluminothermic reduction produced the highest grade manganesealloy. The slag-metal equilibrium involving manganese, silicon and their oxides was investigated and it was found that equilibrium was not attained in any of the experiments, due probably to the very low rate of reactions involving silicon. This could be used to advantage in practice to achieve higher manganese levels in the alloys.

Jan 1, 1998

Conceptually coal reserve assessment is simple but in practice it presents many problems. These arise from the origin and geological history of coal seams and from the diverse nature of the coal itself. The suitability of a coal for a particular use depends upon its type and so sheer quantity of reserves does not guarantee the adequacy of coal reserves for all requirements. Codes have been formulated to counteract the effects of subjectivity in reserve assessment. The code for calculating and reporting coal reserves published by the Standing Committee on Coalfield Geology of New South Wales has wide acceptance but the Committee itself recognises that it has shortcomings. Currently the Committee is engaged on the commendable but difficult endeavour of formulating a code that will meet the needs of scientific rigour and professional and commercial ethics and that will allow the specification of an assessment method without constraining it. It is generally agreed in the coal industry that the assessment of coal reserves can not conveniently be incorporated into codes formulated for other resources.

Jan 1, 1979

By G J. Sparrow, M J. Fisher-White

A mineral and chemical characterisation study was conducted on ilmenite-rich heavy mineral concentrates sourced from the western sector of the Eucla Basin in southern Australia. Test work involved using X-ray diffraction (XRD), scanning electron microscope (SEM) and electron microprobe-based characterisation methods. Results showed considerable variability in the degree of ilmenite alteration between deposits with TiO2 contents varying from 53 - 63 wt per cent TiO2. Notwithstanding variability between individual deposits, the samples all had [Ti]/[Ti+Fe] ratios >0.5 consistent with a mineral assemblage of hydrated ilmenite or the hydrated, Ti-rich alteration phase pseudorutile (Fe3+2-x Ti3O9-3x (OH)3x). Accessory phases consisted of rutile (primary and secondary), zircon, aluminosilicates, quartz, Fe oxyhydroxides and spinels. Results for the most altered material are broadly comparable with data for ilmenite concentrates from the eastern margin of the basin. The mineralogy of the western Eucla Basin concentrates and the minor element composition of the ilmenite grains suggest they could be upgraded to synthetic rutile by a modified Becher process.

Jan 1, 2008

By Driver R. C, Moelle K. H R

This paper is dedicated to the memory of our friend Peter McKenzie who contributed much to the knowledge of the New South Wales Coalfields.ABSTRACTA fossil river system was recently mapped over parts of the Southern Coalfield, N.S.W. This river system occurs in the roof strata of the Bulli Seam. Sandstone of a fluvial nature was deposited in its course. The sandstone exhibits strong sedimentary vectorial properties and has a marked influence on strata-control in colliery workings.The sedimentary features analysed indicate an approximate S200W flow direction. Petrological studies reveal a clastic, well-cemented sedimentologically and structurally anistropic rock type. Washouts have been found and isopach maps of both sandstone and underlying roof-strata have been compiled. Relevant measurements were carried out in existing colliery workings and on bore cores.Optical determinations of feldspars revealed the presence of plagiocIase feldspars with few exceptions. Most of the feldspars are altered to clay minerals. It was found that a geographical trend exists in the distribution of feldspars, with more basic plagioclase in the northern part of the field.The source area of the fluvial sandstone lies to the north of the Southern Coalfield.Petrofabric analyses were done on several specimens of the fluvial sandstone. In the vicinity of major disturbances, penetrative fabrics were discovered.Calcites (e, 0112), micas (001), and quartz (crystalIo graphic c) show preferred orientations.

Jan 1, 1967