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Despite technological improvements and better understanding of the hazards, coal dust explosions stilI occur. Experimental explosions in galleries in various countries extend knowledge with the constant aim of providing safer working conditions. The inadvertent ignition of an accumulation of methane is the traditional initiator of the coal dust explosion.There are specific parameters of coal dust explosibility and explosion propagation, including the important volatile matter in the coal, fineness and dispersibility of the dust and its concentration. Accepting that initiation cannot be absolutely prevented, it is necessary to consider explosion suppression. While both limestone dust and water are the chosen explosion suppressants, in practice water has more limitations to its efficacy when related to the degree of explosion violence. These data give rise to the criteria for explosion suppression, differences in favoured mining geometries, and using the same principles, to differences in suppression treatments.

Jan 1, 1988

Implementation of an Energy Efficient Dry Grinding Technology into an Anglo-American Zinc Beneficiation Process

Sep 13, 2010

By I M. Platten, C J. S Sangster, Y Xie

The Cononish gold-silver deposit is a steep, relatively narrow quartz-vein system, with a current total mineral resource of 154 000 oz Au and 589 000 oz Ag. The northeast-southwest trending system was emplaced into late Proterozoic metasediments, and postdates metamorphism and associated Caledonian Orogenic foliations. Assay and mineralogical data show that gold and silver is spatially associated with sulfides in quartz. The main sulfide is pyrite, but galena, chalcopyrite and sphalerite occur in small amounts. Gold occurs as electrum, with minor native gold, and silver occurs additionally as tellurides and native metal. The gold/electrum is fine-grained, generally less than 100 microns in size. The main ore shoots plunge 45¦ south-west, have a 40 m to 80 m intersection with the existing underground development and extend between 40 m and 260 m down plunge. Small-scale sulfide-bearing domains within the vein carry the highest gold grades. They collectively define the ore shoots, where one or two, and rarely three, of the domains are present at an individual site in the vein. Discontinuity of individual domains, variation in domain thickness and internal heterogeneity results in short scale variation in grade across the structure. Geological mapping along a 1.2 km exploration adit has provided critical æconditioningÆ data to support resource evaluation based on development and relatively wide spaced drilling. In addition, it has provided an indication of potential challenges that could be encountered during production.

Jan 1, 2009

The mineralogy and textures of a portion oC ore from the 25 level northern orebody, North mine, Broken Hill are described. This ore, in places, contains up to 70 per cent cubanite (CuFe2S3 ) which has crystallized directly with other sulphides and associated gangue minerals.Several breakdown reactions involving the cubanite are also considered.

Jan 1, 1969

By D Craw

At Reefton, mesothermal gold deposits occur in the Ordovician Greenland Group basement and bituminous coal deposits occur in overlying Eocene Brunner Coal Measures. These different resource types occur in close proximity to one another in the same topography, vegetation and climate. Both types of resources have been mined for many years and as a result historic mining areas discharge water with chemistry reflecting the mineralogy of the deposits. Coal measures release natural acid rock drainage throughout the region due to oxidation of pyrite in coal and associated sediments. Levels of acidity are increased in mining areas, and pH near three is common. Gold mines contain pyrite, arsenopyrite and stibnite. Discharge waters from these sites have pH near seven because of the high acid neutralising capacity of the basement rocks. Both coal and gold mining sites have iron oxyhydroxide precipitates in drainage waters. These precipitates are more abundant at gold mining sites, and one deposit is up to 5 m thick. Iron oxyhydroxide at coal mine sites contain Zn (up to 89 ppm), Ni (up to 10 ppm), As (up to 163 ppm), Cr (up to 23 ppm), Pb (up to 16), and Cu (up to 11 ppm). Jarosite group minerals have been identified in the coalmine iron oxyhydroxide, although most of the material is amorphous. Gold mine iron oxyhydroxide contains Zn (up to 353 ppm), Ni (up to 592 ppm), Cr (up to 17 ppm), Cu (up to 72 ppm), Pb (up to 29 ppm), Sb (up to 230 ppm), and this material is particularly high in As (up to 20 wt per cent). Most of the material is amorphous but distinctive zones (mm scale) are As rich (up to 30 wt per cent As oxide). Pharmacosiderite, K2Fe4(As04)3 (OH)5.6.3H20, is a secondary mineral in one deposit. These iron oxyhydroxide deposits are useful indicators for the metals mobilised into the environment by oxidation in the historic workings.

Jan 1, 2003

This paper gives a description of the methods of mining employed at North Broken Hill Limited, Broken Hill, N.S.W.GEOLOGICAL NOTESThe main Broken Hill lode occurs as a replacement of tightly folded pre-Cambrian sediments. Replacement has followed certain stratigraphical horizons and the main bulk of the ore is found where these have been packed into the noses of anticlinal and synclinal folds.Throughout the mine the ore-bearing folds pitch north fairly consistently at 45 degrees, as a result of which two favourable horizons in the same fold appear in plan as separate orebodies and these are referred to as the "Southern Orebody" and the "Northern Orebody" respectively.The general dip of the orebodies to the west is about 60 degrees. A typical sill is shown in the plan of the 1,400-ft level (Fig. 1).Both the hanging wall and footwall rocks throughout the mine are weak and, as a result, it is necessary that the hanging wall must be well supported after ore extraction, to prevent subsidence. The weakness in the footwall is confined to a narrow zone, approximately 60 feet in width. This weaknes.q is a source of trouble in the development headings which pass through it, It is sufficiently crushed to transmit weight from the overlying wall to the gangways below.Another feature causing ground instability is the presence of many faults. Although their effect on the shape and character of the orebody is relatively small their...

Jan 1, 1940

By Jones S. C

The problem of sealing a fluid serieite zone at a hole depth of 4000 ft was overcome by using a composite non-return valve plug and rod assembly which enabled cement to be forced under pressure into the zoneà

Jan 1, 1966

By Elford H. S

Mr. H. W. GEPP said he desired to bring particular attention to this paper. The underlying intention of the Development and Migration Commission when the paper was prepared was to place at the disposal of Australian miners and metallurgists the story of the development of tin metallurgy as it had been advanced in other countries, particularly Great Britain. They had very considerable resources of low-grade tin-bearing metals in the eastern coast of Australia particularly, and they need not anticipate that tin was going to remain at the extremely low price at which they saw it to-day. The Commission felt that it was most desirable to place 'on record, and make easily available, the story of the treatment of comparatively low-grade tin ores in other parts of the world.Arrangements were made that the technical staff at Australia House, in conjunction with Mr. H. S. Elford; should collect this information so that in due course, when Australia awoke to an interest in low-grade deposits, of which there were many throughout Australia, this story would then not,have to be gathered from other areas and other places of the world. The -paper was a contribution which would turn out to be of very great value. He suggested to the younger members that this thorough contribution could be made the subject of study so that they would be ready to assist in the developments which must come. Mr. WM. APLIN said there was one point in connection with the paper upon which he would like to speak. While at Mount Morgan he had occasion to test some highly pyritic tin ore by flotation, with a view to separating the cassiterite from the pyritic mineral.Instead of accomplishing that, it was discovered that it would be possible to eliminate as much as 50% of the total weight of ore in the form of a pyritic flotation concentrate, which would contain...

Jan 1, 1930

A large body of porphyry-type copper mineralization occurs at Panguna in southern BougainviIle. It is associated with the intrusion of quartz diorite/granodiorite into andesites, particularly with the contact zone. Metasomatism of both intrusives and andesite resulted in the formation of biotite pseudomorphing hornblende and the veining of the resultant biotite diorite and biotitized andesite by quartz-chalcopyrite veins with pink orthoclase and dark biotite selvages, respectively.The orientation of intrusives and veins appears to be controlled by premineralization fault-joint patterns in the intruded andesitic Kieta Volcanics.

Jan 1, 1968

By Linge HG, Fernandez PG, Hughes HC

Aqueous oxidation is a possible alternative to roasting for the processing of gold bearing arsenopyrite (FeAsS) concentrates. The reaction has been studied by voltammetry and this has shown, for the first time, that FeAsS can be readily dissolved without passivation at room temperature in dilute sulphuric acid at relatively modest oxidation potentials (0.7 V SHE). The reaction forms sulphur on the mineral surface and the oxidant consumption is thus minimal. Two practical modes of slurry oxidation are listed.

Jan 1, 1989

A poured slag bottom is universally considered to be the best type bottom for copper reverberatory furnaces. It is impervious to molten matte and ready for immediate use.When molten slag is not available a monolithic silica bottom is the second best; such a bottom has been adopted at Mount Morgan. The laying of such a bottom is a phase of smelter construction on which so little real information is obtainable that a day to day record of such a recent example as Mt. Morgan's 19 ft. x 40 ft. reverberatory may be of interest. The work was done under the direction of E. Pesout, of McGill Smelter, Nevada. PREPARATION OF THE BOTTOMA 26-inch bed of closely packed firebrick with sand-filled joints was first laid on the clean, dry concrete foundation and the whole dried out by small fires maintained on the brickwork for several days. Ninety tons of silica sand was meantime thoroughly dried and stored in clean drums. This sand must be low in FeO and CaO and contain about 95% Si02 , the majority of which should be present as tridymite. This form of silica shows little expansion at high temperatures, for it is the form stable between 870° and 1470° C.Its presence thus minimises disturbance to the bottom by the expansion which, during the burning in, would mark the transformation of quartz to tridymite.

Jan 1, 1939

By Dippenaar R, Evans T

Twin-roll continuous casting technology is rapidly approaching commercialisation. Fundamentally different than conventional continuous casting, heat transfer and hence solidification during twin-roll casting are governed by the interfacial melt/mould thermal resistance, as opposed to the resistance of the solidifying shell. Under these conditions the interface resistance is predominantly controlled by the melt/substrate wetting behaviour. The very early stages of melt/mould contact are characterised by highly transient heat transfer conditions. The overall melt cooling rates prior to the formation of the first solid are reported to be in the range of 1000 - 50000 K/s with melt undercoolings of up to 300 K. At the points of intimate melt/mould contact the thermal resistance is approaching zero, where cooling rates and undercooling much larger than those reported in the literature are probably occurring. Improved wetting will reduce the energy barrier for nucleation while at the same time increasing the cooling rate of the liquid. Since the overall nucleation rate is controlled both by the rate of cluster formation and the rate of atom transfer to the nucleus, a critical cooling rate will exist above which the nucleation rate is expected to be reduced. Under these conditions, it is possible that the first solid phase to form is a metastable glass which subsequently transforms into a crystalline phase. The implications on nucleation and early growth are also discussed.

Jan 1, 1999

By Morgan W. M

It is not the primary object of this paper to treat with the scheme of prospecting in detail, but it is considered that a brief description of the broad lines is necessary so that the significance of the points to be discussed later may be appreciated.The finding of payable gold reefs on the Bendigo field resolves itself into a two-fold problem, firstly the location of quartz bodies, and secondly the location of gold shoots in such bodies. The country rock of the field has been folded and faulted, and the occurrence of known reefs is associated with the fold axes and the faulting. The "lines" of the field are the anticlinal axes, and practically all known reefs are at or near centre country. Very little work has been done on the synclines, which may have some potential value.Quartz has been introduced along the fracture systems, and gives rise to the three main types of reef met with on the field, namely, the "back," which is similar to a bedded quartz reef and is formed along a bedding plane fault; the "saddle," which forms at the crest of the anticline and has the typical shape from which it takes its name; and "spurs," which are irregular masses of quartz, making off reefs of the first two types.As the fracturing throughout the field is widespread and fairly intense, the first problem, that of finqing quartz, is comparatively simple, and any regular system of blocking out the ground will be productive of quartz bodies.*Field Superintendent, Bendigo Mines Ltd. Assistant Field Superintendent, Bendigo Mines Ltd.

Jan 1, 1936

By Keet B. A, Waid J. S

The Gippsland Basin is one of Australia's most important producers of petroleum products. An inevitable byproduct of the production, refinement and transport of the millions of barrels of oil is thousands of tonnes of waste. These wastes are generated from the wellhead through to the petrol bowser and range from oily brines and coal tars to oil and petrol contaminated soils. The vast majority of these wastes are of a relatively low toxicity and most importantly are carbon-based and biodegradable. Current disposal practices tend to ignore the latter characteristic and inappropriate and/or expensive waste disposal solutions such as landfilling (tipping), incineration or ocean outfalls are the result. A very cost effective and environmentally friendly alternative is land treatment of such wastes. Landfarming, as it is called, has been successfully practiced in Europe for over a decade. Essential features of the system are: ò Application of a predetermined quantity of biodegradable waste in liquid, sludge or highly contaminated soil form, to pre-ploughed soil with concurrent addition of nutrients (N, P and trace elements) and lime to encourage bacterial activity. ò Harmless bacteria already present within the soil break down the carbon-based compounds into carbon dioxide, water and waste heat, WHILE concurrently generating new cells. The breakdown occurs over a period of weeks to months and continues with time with the extremely low levels of the more difficult waste types being the last to disappear. ò Further waste is applied to the soil at regular intervals. The treatment area may be dedicated to landfarming or may be used alternatively for agricultural purposes. Application rates vary but may be as high as 800 tonnes per hectare per year for wastes such as refinery sludges.

Jan 1, 1992

By Hannan J. C

In New South Wales, development applications for major coal mining proposals are determined by the Minister for Planning and Environment and applications for mining leases and other mineral titles are dealt with by the Minister for Mineral Resources. The environmental conditions placed on the development consent, the coal mining lease and the approvals and licences under the pollution control legislation, amount to a substantial component of any new project's planning and commissioning considerations.An outline is presented of the framework within which various approvals are granted and conditions for environmental management are imposed upon mining projects. The principles and concerns, as perceived by the regulatory authorities, on which the majority of approval conditions are based are also outlined.No attempt has been made to analyse the extent to which these principles or standards are achieved in practice, nor to discuss the degree to which some of the conditions are achievable with the current status of technology and economics in the coal industry.

Jan 1, 1987

By W L. Jennings

This paper summarises work undertaken to date as part of an investigation into the mineral resources of the proposedNorth West South Island National Park. The area covered by the proposed national park is underlain by many rock types that have undergone a long and complex history of evolution which has endowed it with some of the best potential for a wide range of different minerals in New Zealand. Many of these minerals occur only in this area or in Fiordland National Park.   The first gold-rush in the area occurred in 1856 and followed the discovery of payable gold at Lightbands Gully, south of Collingwood. The miners first focused on the alluvial deposits but soon shifted attention to lode potential. The total historical gold production for the area may be over 400 000 oz (NZ$250 - NZ$295.6 M at 1993 prices).   In addition to gold, a wide range of other minerals have been reported from the area including molybdenum, copper, nickel, zinc, silver, bismuth, stibnite, lead and antimony. The Onekaka iron-ore deposits have produced small tonnages of ochre and iron-ore at various times. Tungsten, platinoids and other metals have been. given only minor attention. The diverse geology of the Northwest Nelson has resulted in the occurrence of many industrial minerals which have been exploited in generally small-scale operations. Aggregate, chrysotile asbestos, clay, dolomite, marble, limestone, dimension stone, rip-rap, talc-magnesite and wollastonite have all been produced.

Jan 1, 1993

By W Farnworth

The Huntly West Mine has undergone significant changes in the last two years, which will affect the remainder of the mine's life. The paper describes the evolvement of plans and an overview of the technical considerations made in planning for and implementing the first New Zealand longwall operation. The technical investigations involve the longwall equipment, exploration, ventilation and strata control. The focus on these areas was to ensure that unacceptable project risks were addressed. Implementation of longwall mining at West Mine is planned in three phases, Development, Panel One extraction trial, and Full Longwall operation.   At present the development phase is complete, longwall installation is in progress and production start-up is planned for the end of August, 1991.

Jan 1, 1991

Factors of importance in the ntilization of coal fines are mentioned, and the results of flotation tests on coal fines from three important coal seams in New South Wales are presented.INTRODUCTIONEconomic utilization of fine coal is an important problem in the Australian coal industry, particularly as the proportion of fines mined is increasing with progressive mechanization.While the use of uncleaned coal fines may be economic, it may be preferable to beneficiate them, but the most economic process must be selected.For beneficiating coal finer than about 28 mesh, froth flotation can be applied, but mining engineers should avoid practices that may be detrimental to flotation. Such practices include the indiscriminate use of water, particularly that containing a wetting' agent, for dust suppression. In addition, clay stemming in wet conditions may produce slimes which could adsorb on coal surfaces, while the use of oils and greases as well as the application of stone dust and chlorides in roadway consolidation may influence adversely fine coal beneficiation.This paper deals with the application of flotation to samples of fine coal from the Bulli, Greta, and Victoria Tunnel seams. In addition a discussion is given of the mineralogical constitution, size analysis, and degree of liberation of ash constituents of the various samples.COAL SAMPLESRepresentative samples of coal from the Bulli, Greta, and Victoria Tunnel seams were obtained for testing.

Jan 1, 1961

By D M. Hunter, S M. Iveson, K P. Galvin

For low density materials such as coal, density-based fractionation of particles via the sink-float method is relatively simple due to the availability of liquids of suitable density; however, for high density minerals, suitable heavy liquids are less available and those that are available are expensive and pose significant hazards. At best, sink-float separation can be performed up to densities of 4400 kg/m3 with the use of Clerici’s solution at elevated temperatures. Hence the direct measurement of grade-recovery and density-partition curves is problematic. Therefore, in most cases, beneficiation plants must rely on methods such as QEMSCAN, density tracer particles or very limited information to guide them in the design and optimisation of their plants.This paper describes a density-fractionation method utilising laminar flow through a system of parallel inclined channels to generate a series of overflow fractions at different flow velocities. Here the particles are subject to precise hydrodynamic forces with minimal dispersion or mixing. The size distribution of each overflow fraction at a given flow velocity is obtained using a laser particle size analyser, and combined with a laminar flow model to deduce the corresponding density distribution. The paper describes the application of the method to measure the separation achieved using a REFLUX Classifier to obtain the corresponding feed, product and reject ‘washability curves’, and in turn the full partition surface. Approaches used to corroborate the findings are discussed.CITATION:Hunter, D M, Iveson, S M and Galvin, K P, 2017. A batch elutriation technique for the density-based fractionation of iron ore, in Proceedings Iron Ore 2017, pp 195–104 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

Except for uranium search, conventional oil well logging techniques are relatively little-used in mining exploration. The main reasons for this are cost and an apparent lack of awareness of the potential use of the methods in the search for ore. However, relatively inexpensive portable units are currently available for performing the simpler electrical and radiometric logs in diamond drill holes.The emphasis in oil exploration logging programmes is largely on the estimation of porosity. In most mineral work, however, porosity is not very significant, and factors such as mineral conductivity and radioactivity assume an important role.The Bureau of Mineral Resources (BMR) during a programme to explore for uranium and associated base metals in the area east of Rum Jungle, N.T., carried out electrical and radiometric logging of diamond drill holes as a routine part of their investigations. Case histories are described in which the logs were used to aid in defining stratigraphic sequences and transgressive structures in base-metal prospects. Some surface geophysicalanomalies were explained by the logging: induced polarization and electromagnetic anomalies were related to black slate; and self-potential anomalies were related to oxidation of pyrite black slate, or apparent electrokineticeffects in the black slate. The logs provided an objective appraisal of the rock units penetrated and thereby helped to differentiate lithologies.Borehole logging, including newer techniques such as downhole analysis, could be done in geological and geophysical investigations in other areas for a relatively small cost with a considerable potential gain of information.

Jan 1, 1978