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Your Excellency, on behalf of the Council of the Australasian Institute of Mining and Metallurgy, and, indeed, on behalf of everyone present, I extend to you a welcome, and our thanks for your gracious acceptance of the invitation to be here to-day and, later on, to present Honorary Membership Certificates. I also welcome the several official representatives of our Allies, of Great Britain and our sister Dominions.To Messrs. E. C. Driffield and E. J. Rigby, two of the original Foundation Members, who are with us to-day, I extend greetings.The present occasion is opportune to express, on behalf of a representative body of professional men, deep appreciation of the sacrifice which His Majesty the King has made, and will continue to make, by appointing His Royal Highness the Duke of Gloucester as Governor General of Australia and, therefore, His Majesty's senior personal representative in this country.I suppose, that as the primary reason for our assembly to-day is to celebrate the Fiftieth Year of the Institute's existence, I should properly on this occasion, give an account of its history and development. However, as this subject was ably covered by Mr. L. V. Waterhouse, in his Presidential Address in 1938, I trust I may be excused for selecting some other subject. I shall, therefore, exercise my privilege as President and give you a short history of the Mining and Metallurgical Industry of this country with special reference to its effect on the development of the Commonwealth and on the national economy. I apologize in advance for any statistics which I inflict upon you; some of these will be three or four years out of date, because of censorship restrictions. I shall as far as possible refer firstly to the industry prior to and including 1893, the Institute's foundation year, and then to subsequent development.Australia, is pre-eminently a pastoral and agricultural country and it leads the world in the production of wool. Nevertheless, it has an international reputation as a producer of gold and various metals and of minetal products.The development of gold mining in the decade 1840-50 was an epoch-making event in Australia's history, because, to quote one writer's apt phrase, "it precipitated Australia into nationhood." It was certainly responsible for a rapid increase in population. Thus, during the period 1841-1861 the population of Australia increased fourfold, from 221,000 to 1,170,000.The effect of the discovery of gold in Western Australia was even more striking. In 1890 the population of that State was 49,000 and in 1900 it was 180,000.Statistics in respect of gold are reasonably complete, even for the years prior to Federation, and it is interesting to note that the gold declared as...

Jan 1, 1944

This modern plant consists of a battery of 72 Otto Wilputte Compound Under-jet Ovens with extensive plant for the recovery by-products. The ovens produce 9000 tons of furnace coke per week together with some 17,000,000 cub. ft. of coke oven gas, which is used for heating purposes throughout the works and for heating the ovens.Coal is supplied from the, company's colliel'ies and is stored under a Coal Handling Bridge of 264 ft. span and 365 ft. overall, capable of handling 250 tons per hour. The coal storage space of 1600 ft. can. be extended to a maximum of 2800 ft.Preparation of the coal for coking involves fine grinding which is carried out as follows:-Coal is dumped from rail waggons on to a conveyer belt which delivers it to a 12 ft. x 22 ft. Bradford Breaker, with a capacity of 400 tons per hour. The coal, then approximately 4 in. in size, passes, to the mixing bins; and after careful blending is reduced in the,hammer mills to a fineness suitable for the ovens.The fire coal is elevated to the main storage bin over the battery for subsequent charging by electric larry car. The average cokingtime is 15 hrs. 36 mins. At the end of ,this period the doors, are removed and the coke pushed from the oven by a mm. The coke, is, then quenched with fresh, water and sent to the Blast Furnace in 50-ton Copper Waggons.The gas is exhausted from the ovens by Brown Boveri turbine, exhausters of 23,000. cub, ft, per min. capacity. Exhaust steam from these is used for various. purposes in the By-Product plant. After removing the last traces of tar by Electrostatic Precipitators', the gas is bubbled through sulphuric acid, the ammonia forming ammonium sulphate, which is subsequently washed, dried and bagged for sa,le as a fertilizer. The gas then goes to the Benzol Scrubber Towers, where benzol and other derivatives are recovered and later redistilled and purified. The cleaned gas is then piped to the main works for heating purposes, being used with tar to fire the steel furnaces, and also the soaking pits and reheating furnaces.BLAST FURNACES.The company is at present operating two Blast Furnaces of 800, and 1000 tons nominal daily capacity respectively. The latter was...

Jan 1, 1938

By P Mitchell, J Proffett, I Munajat

Batu Hijau is an island arc porphyry copper-gold deposit located in the southwest corner of Sumbawa Island in the Sunda-Banda archipelago of Indonesia. Southwest Sumbawa Island is underlain by Early Tertiary, low-K calc-alkaline to weakly alkaline volcanic and intrusive rocks. Within the mine area the oldest exposed rocks are medium- to thick-bedded, medium to coarse andesite volcanic lithic breccia, thin bedded, fine-grained volcaniclastic sandstones and mudstones and hypabyssal porphyritic andesite. In the eastern portion of the mine area there is a thick sequence of quartz diorite that postdates the andesites. A small stock of Equigranualar Quartz Diorite predates the Batu Hijau deposit and occupies the contact between the andesitic volcaniclastic sequence of rocks and the Porphyritic Quartz Diorite. Batu Hijau is a world-class copper-gold deposit that has a drill indicated mineable reserve of 914 million metric tonnes grading 0.525 per cent copper (10.58 billion pounds copper) and 0.403 g/t gold (11.8 million ounces gold). Mineralised material not in reserve accounts for an additional 580 million metric tonnes at 0.328 per cent Cu (4.19 billion pounds copper) and 0.171 g Au/T (3.19 million ounces gold), and including an oxide copper resource of 57 million tonnes at 0.37 per cent Cu and 0.12 g Au/T. Copper and gold mineralisation is directly related to quartz veining and wall rock alteration that developed with multiple tonalite porphyry intrusions. The tonalites were emplaced along the contact between the andesitic volcaniclastic rocks and quartz diorite intrusives. Copper and gold are zoned around the porphyry intrusions, which are designated by their contact-age relationships and other features as Old Tonalite, Intermediate Tonalite(s), and Young Tonalite(s). The Old Tonalite was the first copper-bearing intrusion, and although it is the smallest intrusion it has the highest quartz vein density, the strongest alteration and the highest grade. At least two tonalite porphyry intrusions followed the emplacement of the Old Tonalite. Each of these intrusions was associated with less quartz veining, weaker hydrothermal alteration and lower grade copper and gold than the previous intrusion. The intrusive cycle culminated with the emplacement of the Young Tonalite, which contains relatively few quartz veins, is weakly altered and mineralised. Hypogene hydrothermal alteration and sulphide mineralisation developed in five temporally and spatially overlapping stages. These stages consist of Early, Transitional, Late, Very Late, and I Zeolite alteration. Early alteration and sulphide mineralisation accompanied each tonalite porphyry intrusion, but with diminished intensity in each subsequent intrusion. Transitional and later stages of alteration and mineralisation postdate the tonalite porphyries and overprint Early stage alteration and mineralisation. Early alteration and mineralisation consisted of biotisation, secondary magnetite and plagioclase development, fine porphyry-style stockwork veining and ore mineralisation. Magnetite-biotite????quartz stringers and dark micaceous (biotite-sericite) veinlets were developed. The veinlets were accompanied by biotisation of magmatic mafic minerals and groundmass. Thin, irregular and discontinuous æAÆ type quartz veinlets and fine-grained chalcocite, digenite and bornite mineralisation accompanies the Early alteration. It is hypothesized that most of the copper mineralisation was originally deposited as bornite, digenite and chalcocite. Secondary plagioclase was added along the selvages of the early quartz veinlets. Early alteration is pervasive within and proximal to the tonalite porphyries. In the distal portions of the deposit, andalusite and anthophyllite formed at intermediate to shallow depths, and in the deeper portions of the deposit, respectively. The andalusite and anthophyllite probably developed at the same time as the early magnetite-biotite-quartz alteration in the core of the deposit. Transitional-age alteration consists of oligioclase/albite-sericite-chlorite- quartz-¦vermiculite and is associated with æBÆ quartz veins. Through-going planar æBÆ veins are thicker than æAÆ and æA-familyÆ veinlets and have chalcopyrite????bornite along vuggy centrelines and narrow oligioclase????albite alteration envelopes. Rare æCÆ chalcopyite¦quartz veinlets were also formed during Transitional alteration. During Transitional alteration early copper sulphide minerals (chalcocite, digenite and bornite) are converted to bornite and chalcopyrite. The majority of the copper (50 - 70 per cent) in the deposit is contained in ores in which chalcopyrite is the predominant sulphide. Late alteration consists of feldspar destruction and replacement by sericite and other minerals. The late alteration is accompanied by the development of æDÆ sulphide veinlets and veins. These veins consist of pyrite and quartz????chalcopyrite. Within the halos of the late pyritic veinlets biotite is replaced by sericite, quartz-sericite, quartz-andalusite, or quartz-pyrophyllite+kaolinite replace plagioclase, and magnetite is converted to specularite and/or pyrite. In the periphery of the deposit, the feldspar destructive alteration, together with outer zones of Transitional-age alteration, constitutes what is commonly referred to as a æpropylitic zoneÆ. Very Late hydrothermal alteration is also characterised by feldspar destruction, but differs from Late alteration in that feldspar is replaced by smectite in association with sericite and chlorite. Sulphide mineralisation in this stage consists of sphalerite, galena, tennantite, pyrite and chalcopyrite. The last stage or I Zeolite alteration consists of low-temperature, open space filling consisting of stilbite or laumontite¦calcite. Supergene oxidisation of the orebody extends to a maximum depth of 210m. Isolated deep oxidation occurs along open fracture zones to depths of ~400 metres along æDÆ vein filled fracture zones. Weak supergene copper enrichment occurs in a thin horizon (15 to 60 m thick) that blankets the top of the deposit. The main supergene copper mineral is secondary æsootyÆ chalcocite replacement of sulphide grains and as veins.

Jan 1, 1999

By Cawte D. C, Just G. D, Whitchurch K. D

The stringent marketing specifications included in coal contracts mean that coal producers must supply cleaner and more consistent coal than may have been formerly required. Geostatistics has the potential to aid in the accurate estimation of the washability characteristics of coal. A prediction method, the Kriged Service Variable Approach has been developed.A Computer Aided Drafting and Design system has proved useful in the development and application of the approach. The geostatistical approach has been tested against coal geological and borehole data and applications discussed.

Jan 1, 1987

Minerals processing needs a step change in energy efficiency. While the search for new technology breakthroughs is important, huge gains are still available by better using existing research outcomes. This potential remains untapped due to a combination of organisational 'silos', inappropriate performance measurement, and poor science in some areas. It is time to see the elephant in the mill.

Sep 13, 2010

By G Siboni, A Correa De Araujo, M Gotelip Barbosa, M J. Venturini

In support of the development of its Liberian iron ore project, ArcelorMittal Mining Research and Development (AM Mining R&D) has performed characterisation and beneficiation test work on drill core samples received from the proposed mine area. In addition to this, a sinter feed product was composed by blending and processing the drill cores in order to predict sintering performance of the ore. This article presents the methodology used to prepare the drill core blend for characterisation, as well as describe the sinter pot trial. The results are presented, demonstrating how important this type of study is for the development of an iron ore deposit.CITATION:Gotelip Barbosa, M, Siboni, G, Venturini, M J and Correa de Araujo, A, 2017. The use of drill core blends to predict sintering performance, in Proceedings Iron Ore 2017, pp 297–302 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By D Craw, S Clearwater, S Hammit, C Smith

Prior to rehabilitation, plant cover on quartz gravel overburden at Wangaloa coal mine was highly patchy. Stabilisation techniques have since considerably altered the condition of the main overburden yet deposits in the east and west remain largely intact. On the eastern overburden, three distinct zones of revegetation have naturally developed: Zone 1 represents a dense plant cover, Zone 2 a patchy cover and Zone 3 a sparse cover of isolated plants. Aerial photographs show much of the eastern overburden was deposited between 1940 and 1960s. Yet we found that the temporal scale of deposition did not wholly account for the differences observed in vegetation development. To investigate other influential factors, we set up 12 study plots using four replicates in each vegetation zone. The diversity and density of plants in each plot were measured to quantify the degree of vegetation development. Samples from the substrate in each plot were collected using soil cores to a depth of 10 cm. Cores were analysed for indicators of nutrient availability, metal content and physical composition. We found that substrate chemistry varied between individual study plots, but showed little difference overall along the vegetation gradient. Substrate physical differences were much greater. The ratio of coarse quartz pebbles: fines was considerably higher in Zone 3 than other zones, and within zones where plants were not growing. Bulk density also increased successively from Zone 1 - 3. We found clear evidence for the reversed stratigraphy of excavation superimposed over the time scale of deposition, and the corresponding nature of fine particles. The rate of revegetation was therefore highly dependent upon the substrate composition of the last surface deposit from the dumping truck. Our data suggests an optimum ratio exists between inert coarse material and a fine matrix for progressive natural vegetation development on mine substrates.

Jan 1, 2004

By W Herrmann, R R. Large

Volcanic-hosted massive sulfide (VHMS) deposits in ancient, submarine volcanic belts of Australia include mound, lens and sheet-style Zn-rich polymetallic deposits, massive and disseminated pyritic Cu-Au deposits and disseminated, stratabound Au-only deposits. Variation in morphologies, metal ratios, volcanic environments and alteration features indicates there exists a spectrum of deposits from the classic VHMS model, to hybrids between VHMS-porphyry Cu and VHMS-epithermal end members. Zn-rich, polymetallic deposits form eitheron, or just below, the seafloor, whereas the Cu-Au and Au-only deposits form sub-seafloor by replacement of specific volcanic lithologies. Alteration zoned outwards from quartz -> chlorite -> sericite ¦ carbonate is typical of VHMS deposits across the spectrum. Quartz and carbonate alteration is dominant in the Au-only systems,chlorite alteration is commonly developed close to Cu-rich ores, and sericite and carbonate alteration zones are well developed in the stratiform Zn-rich ores. The most useful geochemical vectors for Zn-rich ores are the alteration index [AI=100(MgO + K2O)/(MgO + K2O + CaO + Na2O)], the chlorite-carbonate-pyrite index [CCPI=100(MgO + FeO)/(MgO + FeO + K2O + Na2O)], Mn content of carbonate, Mg/(Mg+Fe) ratio of chlorite,whole-rock Tl, Sb and Ba/Sr ratio, S34S of pyrite, and whole-rock S18O. The most useful vectors for pyritic Cu-Au ores are AI, CCPI, S/Na2O ratio, Na content of white mica, and Fe content of carbonate.

Jan 1, 2002

Experimental results are presented for the anode overvoltage as a function of current density for different alumina concentrations in an alumina reduction cell. Voltage changes due to the electrolyte resistance and also the decomposition voltage, have been evaluated as a function of alumina concentration and anode current density. From these values of voltage, changes in the total cell voltage have been derived for changes in alumina concentration for different anode current densities. The results show that for each operating current density there exists a discrete alumina concentration that defines a minimum reduction cell voltage. Discussion is made about potential savings in power consumption when the alumina concentration is controlled.INTRODUCTIONThe standard procedure in the aluminium industry when analysing the cell-voltage required for the Hall-Heroult process for reduction of alumina, is to subdivide the total voltage into the following components (e.g. Pearson, 1955; Maritell, 1960).1. ohmic drop through busbars and joints2. ohmic drop through cathode lining3. ohmic drop through anode4. ohmic drop through electrolyte5. overvoltage at anode6. electrolytic decomposition voltage.(Overvoltages ,at the cathode are of negligible magnitude at all practical current densities.)It is understandable that the voltages assigned for each factor invariably differ for different workers...

Jan 1, 1965

By D Craw

The Old Man Range, south of Alexandra, in central Otago consists of a package of highly folded greenschist facies schist of the Wanaka lithologic association. The range is crosscut by several east to ENE-striking high angle gold-bearing quartz veins, (eg Whites Reef and Grays Reef), which were extensively worked in the late 1800s. The range is bounded on its east side by the Old Man Fault, which separates these rocks from generally flat lying and planar Caples Terrane schist. To the west of the Old Man Fault, about halfway up the range, a large subparallel, 100 m wide fault zone strikes NNW and appears to cut off the historic veins. The fault zone consists of highly sheared and folded rocks and numerous high angle cataclasites and centimetre-scale clay gouge zones. Hydrothermal alteration is not apparent and the individual faults and shears are clay altered, possibly due to weathering, without visible quartz veins. Gold, limonite pseudomorphs after pyrite and rutile are concentrated in some of the narrow cataclasites and gouge zones. These mineralised structures are texturally similar to the gold-bearing reefs and may be structurally related. It is postulated that the NNW-striking shear zone and ENE-striking veins may be a conjugate array formed during a period of Cretaceous normal faulting.

Jan 1, 2004

By W E. Vance, B H. Ashton

The emission of seam gases into underground workings in coal mines is acknowledged as a major hazard, particularly methane due to its possible ignition. Acknowledge of seam gas parameters is important for the prediction of gas emission rates into the ventilating air current. They are also important as the basis for the evaluation of the likely contained gas as a possible energy source.   Gas content determinations for the Kupakupa seam have been made at the Huntly West Mine.  Applying the method of Creedy (1986) to face samples, gas contents of 1.80 and 1.66 have been determined. Using desorbed and residual gas content data a content of 1.92 m3/t has been derived. These are on an ash included basis. Calculations using the adsorption equation of Kim (1977) and coal quality have given a gas content of 2.19 m3 t. Long-hole exploration drilling at Huntly West Mine has provided information on gas pressure. A pressure rise test has given a reading of 500 kPa (absolute); this is low compared with the pressure given for the determined gas content from theoretical adsorption isotherms.

Jan 1, 1991

By T Higuchi, L Lu

The quality of iron ore fines have been deteriorating, which has affected sinter quality and productivity adversely. New pretreatment and sintering technologies are therefore required to tackle the gradual change in the quality of iron ore fines. In the sintering process, iron ore fines are first granulated with fluxes such as limestone and coke breeze, and are then loaded and fired in a sinter machine. Sinter productivity and quality are heavily influenced by the reactions occurring in the sintering bed. Hence fundamental understanding of these high temperature properties of ores is urgently needed.Formation of initial sinter melt, penetration and assimilation of nucleus particles by the initial melt, and consolidation and final solidification of final sinter melt are believed to be the key sintering reactions. The assimilation and penetration phenomena have been studied separately in the literature with model particles and diffusion couples and are therefore difficult to relate to sinter quality. In addition, the effect of ore mineralogy has not been studied in detail.In this study, tablets consisting of coarse particles from various iron ore fines as nucleus particles and chemical reagents as adhering fines were made and fired under various sintering conditions to investigate the penetration and assimilation behaviour simultaneously. The degree of assimilation, pore structure, compressive strength of the resultant analogue sinters were evaluated and the relationship between sinter strength and ore characteristics was further discussed. The nucleus particles from Ores A and B were found to be more porous and assimilated more readily with sinter melt, resulting in a viscous melt and a macro-porous sinter structure. The nucleus particles from Ores C and D on the other hand, assimilated less readily with sinter melt, resulting in a fluid melt and a denser sinter structure. This is consistent with the results reported in the literature, suggesting that the present evaluation method can be utilised for studying sintering reactions and predicting sinter quality.CITATION:Higuchi, T and Lu, L, 2017. Evaluation of sintering behaviour based on ore characteristics, in Proceedings Iron Ore 2017, pp 303–308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

At an early stage of the examination of most prospects, samples are taken; and the sample values obtained play an important part in determining the subsequent history of the prospect. It is, therefore, important that. eveJJy effort should be made to interpret asfully as possible the meaning of the observed results. In this connection, it is suggested that examination of the assay values of mine samples by simple statistical methods may bring to light information of considerable value, which might otherwise be missed.Although expert statisticians may derive more information from the available data, those who are, like the writer, less proficient mathematically, may also benefit by applying quite simple statistical methods. At least they will develop a useful habit of thought bywhich they become aware at all times that sampling results only provide estimates of the truth, but that an assessment of the precision of such results may be possible. The object of this paper is to provide some evidence of. the truth of these statements, by theuse of a few very elementary statistical calculations.General.The idea that any mine sample is subject to error from a variety of causes is a very familiar one. Doubt always exists with regard to the representativeness of a perfectly cut sample, and other errors may arise through imperfections of sample cutting, crushing, splitting and assaying. Some causes of error may give rise to "constant" errors, others may cause variable but one-sided "systematic" errors, and others again may bring about variable results without any tendency toward bias on the average. In statistical language, mine sample values are subject to errors which may have either assignable causes or chance causes. The former are those which can be isolated, or should be capable of isolation, while the latter are those remaining when all assignable causes have been removed. A single constant assignable cause brings about bias in all results, and one or more than one variable assignable cause brings about variation between individual results and perhaps an overall bias. The system of chance causes that would remain if all assignable causes were removed would cause variation between individual results but no overall bias. There is no sharp practical line of distinction between the two types of cause) of error; nor is it ever possible by any method of statistical analysis to be certain that there are no assign...

Jan 1, 1950

This paper focuses on two sites in the Mount Pleasant - McCormacks Bay area of Christchurch where residential development has taken place either within or immediately adjacent to former quarries for the extraction of volcanic rock. At the Quarry Road site less overburden was dumped on adjoining land around the turn of the century, and c.1980 dwelling and related construction took place on approximately 6 m of relatively loose fill material without the recognition of its presence or geotechnical characteristics. Subsequent settlements led to abandonment of a swimming pool and the underpinning of the 3-storey architect-designed house, whilst litigation brought by the owner resulted in findings of negligence against both the architects and engineers. At the Tramways Quarry site the Council approved subdivision of the former quarry area in the early 1980s without requiring any geotechnical evaluation of batter stability or related issues. During development it became apparent that significant blast damage had occurred to rock faces, necessitating a variety of remedial measures, and that waste materials had been dumped down faces without regard to long-term stability. Both case studies confirm the requirement for careful documentation of former quarry sites by territorial local authorities as part of their administrative function, and for detailed engineering geology and geotechnical evaluation of such areas prior to any residential use of the land.

Jan 1, 1998

The Wainui Mill was conceived as a 60 - 90 t/d central mill to process gold ores of the Thames area of New Zealand from small mines in the district. The ores of the region exhibit various degrees of refractory response to conventional cyanidation leach due to the fineness of the gold, and association with pyrite. The alternative circuits involving cyanidation, flotation, and possible small-scale smelting are examined. The environmental impacts have been audited by the Commission for the Environment and were found to be acceptable.

Jan 1, 1986

The development of research activities at Risdon and the implementing of a policy of instrumentation in plant processes have, in recent years, entailed a considerable increase in research staff and created an urgent need for more space and modern laboratory facilities. The existing laboratories have been in use for 25 years and are now inadequate. New buildings have been authorized.The new buildings will comprise, firstly, a laboratory building of three floors giving a totai .floor space of approximately 11,000 sq.ft., and a pilot plant building as an annexe to the laboratory building, of approximately 4,900 sq.ft. The laboratory building will accommodate from 20 to 22 research workers, and additional plant operatives will be used for the control of processes in the pilot plant building. The new buildings are designed to provide facilities for three principal functions; the investigation and improvementof existing processes, the development of new processes up to the pilot plant stage, and the control and maintenance of instruments.LOCALITY AND ORIENTATION OF BUILDINGSThe site of the buildings is elevated ground on the eastern side of the main plant, near the main entrance and general office building. There will be no obstruction to sunshine at any time of the day, and the laboratory building will command views of wide radius from wooded hills across the River Derwentto the open sea on the south-eastern quarter.The buildings are located to provide space for future extensions. The main laboratory building faces approx...

Jan 1, 1949

By Graylin R. K, dea T. R, O&apos

The Wolgan Seam of the Upper Permian IlIawarra Coal Measures of the Western Coalfield of New South Wales consists of high volatile, low sulphur, medium hard coking coal with high fluidity. This seam, 1·8-2·4m thick, in the Wolgan area, dips gently at 1°_20 ENE and lies at 160-440m below the deeply dissected surface of the western margin of the Blue Mountains plateau.A detailed study of the deposit has revealed that the Wolgan Seam consists of four main coal plies separated by three distinct stone bands. Each of these subunits is lenticular and displays individual physical, chemical and mineralogical characteristics which exhibit distinct spatial distribution patterns across the area. Most noticeable is the presence of long linear ESE-trending zones of low ash - high volatiles - high fixed carbon - high fluidity which delineate the major distributary pattern within the deltaic environment of coal formation.This seam contains some of the highest fluidity coal in the world.The Wolgan area, close to the western margin of the Sydney Basin, is characterized by:I. a regional, closely spaced, homogenous joint fracture pattern dominated by an orthogonal pair set trending 3400 and 0700, to which the face- and butt-cleat directions respectively of the Wolgan Seam are sub-parallel, and2. a more widely spaced, heterogenous, cross-cutting pattern of regional structural fractures. Zones of bad roof conditions are probably associated with these lineaments which are subvertical and trend in three majordirections, viz., 005°,035° and 115°.

Jan 1, 1980

Iron ore in the Middleback Range area has a density and susceptibility contrast with adjacent rocks, and gravity and magnetic methods are applicable to exploration for it. The gravity method is satisfactory whether the ore mineral is hematite, magnetite, or limonite; the magnetic method is suitable for detecting ores which contain magnetite, such as some hematite ore, magnetite ore, and possible ore in the form of magnetite-bearing schists. jaspilites, and carbonate rocks.Geophysical exploration began in 1948 and is still in progress. The methods which have been used are aeromagnetic (83 per cent), ground magnetic (13 per cent), gravity (3 per cent), and others (1 per cent). Ground magnetic surveys have been made wherever aeromagnetic surveys recorded large anomalies. The gravity method is being used to investigate those parts of the area considered most favourable for ore occurrence.Qualitative and quantitative interpretation of the geophysical data has been made and the rocks causing selected anomalies tested by bores.Magnetite in the Middleback Group rocks produces the major magnetic anomalies in the area. The average magnetite content of magnetite-jaspilite, which is the commonest rock type, is 33 per cent by weight and that of magnetite-carbonate at the Iron Duke-Iron Duchess is 50 per cent. These rock types also contain hematite and the average total iron content of the former is 35 per cent and of the latter 50 per cent.INTRODUCTIONThe geology and iron ore resources of the Middleback Range area were described by Miles (1954). Since 1954, much drilling, mapping, and quarrying has been done but there is no published report of this work.The rocks which constitute the Middleback Range, Camel Hill-Cooyerdoo line, Katunga Hill-Iron Knob, and Ash Range (Fig. 1) belong to the Middleback Group of Middle Precambrian or late Archaean age. Most outcrops of the Group are jaspilites, formerly called banded hematite (or magnetite) quartzite. The high grade hematite deposits...

Jan 1, 1964

By B Belle

Dust sampling is pivotal in estimating the ‘dose’ of dust exposure and in deriving dose-response curves in epidemiological studies. Over the last half century, gravimetric sampling has been the fundamental means for dust exposure monitoring using recognised respirable size-selective standards. In Australia, a gravimetric sampling technique has been followed since 1983 using the Higgins-Dewell (HD) type cyclones (AS2985). The re-emergence of ‘Black Lung’ or Coal Workers Pneumoconiosis (CWP) in Queensland, Australia has re-kindled the need for better understanding of personal dust monitoring, compliance determination, accuracy, timeliness of sampling results and dust control systems. Reporting dust levels in real time empowers miners and operators to take immediate action to avoid being exposed to excessive airborne dust. Two decades of intensive research in the USA has led to the introduction of gravimetric based continuous personal dust monitors (CPDMs) called PDM3700 as compliance tools. The new real-time mass based sensor is a continuous mass based dust monitor using the Tapered Element Oscillating Microbalance (TEOM) principle and is regarded as significantly superior to the current gravimetric sampling methodology.Recently the overall respirable dust standard in USA coalmines has been reduced from the historic 2.0 to 1.5 mg/m3. This paper provides the results of a comparative pairwise study of an existing gravimetric sampler and the PDM3700 carried out in 3 different Australian underground mines. The field results consistently suggest that there is a significant ‘measurement bias’ between the current gravimetric HD sampler and the PDM3700 monitor operated using a similar HD type cyclone. The results show that the currently used cyclone measurements are approximately 59 per cent higher than the ‘auditable’ PDM3700 monitor data at the current compliance limit of 3 mg/m3. Based on a review of the extensive data collected, the differences can in part be attributed to the aerosol size selectivity of the samplers with the current gravimetric sampler used in mines, collecting more larger sized particles (D90 of 15 µm). This finding has significant consequences for historic exposure results and their use in medical surveillance programs, as well as the current approach to non-compliance determination.CITATION:Belle, B, 2017. Pairwise evaluation of PDM3700 and traditional gravimetric sampler for personal dust exposure assessment, in Proceedings Australian Mine Vent Conference 2017, pp 87–92 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By C Rizzardi, M Callahan, J Mahon

Henderson Operation’s underground molybdenum mine has been in production since 1976. Since that historic date, more than one billion pounds of moly has been produced, and over 120 Mt of ore extracted from three different levels and many different panels. The safe and successful operation of Henderson has been, and will continue to be, dependent on utilising an increasingly sophisticated fleet of equipment, advanced designs, innovative mining techniques, best practices in maintenance processes, improvements in crushing and conveying systems, and most importantly, the training and mentoring of the underground staff. These ‘professional mining technicians’ have been essential in the safe and efficient operation and maintenance of the underground mine and convey systems, and will drive the continuous improvements needed to keep Henderson competitive in the growing global market.CITATION:Callahan, M, Mahon, J and Rizzardi, C, 2016. Development of the professional mining technician – Henderson’s underground mine continuous improvement program, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 161–166 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016