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Magnetic anomalies in the Southern Coalfields have been subdivided into two characteristic types. Each type is attributed to a separate cause, one being basement structure, and the other near-surface igneous intrusions.Detailed geological mapping of the area and the ability to sample throughout the coalmines greatly assisted in this subdivision.The Triassic sequence contributes no magnetic effect of its own except to diminish the effect of sources within the underlying formations by raising the level of observation.Detecting the presence of igneous intrusions ahead of colliery working faces by magnetic observations within the coal mines may be of value in preventing accidents caused by gas outbursts and in planning the workings so as to avoid loss of production time.

Jan 1, 1967

The area between Merrygoen and Digilah is located on a structural high that separates the Sydney Basin from the Great Artesian Basin, and hence the stratigraphic succession of younger rocks overlying the basement is relatively thin. The stratigraphy is briefly described and it is shown that fluvial sedimentation prevailed from Upper Permian through to Middle Jurassic times. Flint clays occur in the Permian, Triassic and Jurassic but only those in the Jurassic appear to have commercial value at present. The chemical, mineralogical, and physical properties of the flint clays are discussed.

Jan 1, 1973

By Nicol S. K, Swanson A. R

The poor flotation response of many coals has in the past been attributed to such factors as differences in rank, differences in degree of oxidation, differences in petrographic composition, or slime coatings. The present work shows that while all these factors undoubtedly influence flotation, the size distribution of the feed may override these. Evidence is presented which shows how this factor can lead to substantial losses of coarse coal (>250 µm)from a coal which would normally be considered amenable to flotation. Reasons for this loss of flotation response are suggested together with means of overcoming the problem.

Jan 1, 1978

Study on Flotation of the Low-Grade Magnesite Ore

Sep 13, 2010

By Higgins RJ

Environmental investigations have been undertaken by Ok Tedi Mining Limited (OTML) since 1981 when the Ok Tedi Environmental Study was commenced. Environmental monit- oring and management programmes were implemented in 1983. The programmes included water quality monitoring, river flow and sediment monitoring, surveillance of aquatic biological communities and a health and nutrition survey of the local people. These original programmes have continued, and additional programmes of work have been developed and revised to reflect changing operations and the need to focus investigations on specific areas and issues of concern. In April 1990, following the establishment by the Government of Papua New Guinea (PNG) of environmental management criteria for the Fly River system, compliance monitoring programs were introduced. Details of the compliance and additional monitoring programmes undertaken by OTML throughout the Ok Tedi and Fly catchments, including programmes of investigation in the Fly River estuary, Gulf of Papua and Torres Strait, are presented.

Jan 1, 1991

By Holla L, Tyminski A

Stowing has been successfully used in many countries as a means of controlling surface subsidence, minimi ing incidences of spontaneous combustion, maintaining gate road stability and maximising coal recovery.Australian experience in stowing is limited but in the future increased extraction of thicker and/or multiple seams by longwall operations and resolution of conflict of alternative land u'ses may necessitate the use of stowing in coal mining. At present there is little incentive for mining companies to introduce and operate a stowing system because costs have to be borne by the individual companies and benefits spill over to society and the State. Cost sharing by the industry and State incentives may overcome the problem of cost disincentive.

Jan 1, 1987

By R Tweedie

'The politics of mining in New Zealand' is a topic I chose myself because of its importance in the future of the New Zealand mining industry. There are many people in the industry who are cynical about politics, cynical about politicians and definitely cynical and often critical of political decisions. In fact, many industry people say they don't want to get involved in politics, they just want to get on with the business of exploration or mining. The point of my address is that politics is important and the industry cannot afford not to participate in the political process.

Jan 1, 1991

The Wamum and Idzan Creeks Prospect, located 79km W of Lae, Morobe Province, Papua New Guinea (PNG) was discovered by the exploration arm of Conzinc Riotinto of Australia Pty Ltd (CRAE). The detailed surface exploration and 11 vertical holes drilled by CRAE, combined with the recent work by Highlands Gold Limited, indicate the occurrence of porphyry copper-gold mineral- isation and associated alteration. The prospect occurs within andesitic volcanics of the Middle Miocene Langimar Beds. It is bounded by NE trending faults to the NW and SE. The alteration and mineral- isation is hosted in the andesitic tuffs adjacent to high level quartz diorite and hornblende diorite stocks. A NW trend to alteration and mineralisation is obvious in Wamum and Idzan Creeks. The main alteration type is propylitic with minor zones of potassic alteration. A late sericite-quartz-kaolinite-pyrite alteration overprinted the earlier alteration and mineralisation. Copper and gold mineralisation is related to a quartz-carbonate-chalcopyr-ite-pyrite (¦ bornite) vein stockwork and biotite ¦ K-feldspar alteration. The mineralisation system at Wamum and Idzan creeks is low in total sulphides. It is considered as a high- level fracture-controlled system with limited low grade Cu-Au mineralisation.

Jan 1, 1991

Although small scale mining is regarded by many as of historical value only, this kind of mining activity is still much more widespread than is usually assumed. It has been estimated that it produces as much as ten per cent of the global mineral output. More significantly this figure is often much higher for many of the developing countries of Africa, Asia and South America, signifying the relatively greater contribution of small scale mining to the economies of those countries. It is also noted that small scale mining has always been a feature of mineral production in New Zealand and Australia. An attempt is made to define small scale mining, and the factors determining the suitability of small scale mining operations are discussed. The state of the art in small scale mining is reviewed and the author endeavours to rationalise the important parameters which contribute to successful small scale mining operations and discusses how these parameters may be optimised. The benefits of small scale mining to the mining industry as a whole and to the community at large are outlined. The paper concludes by emphasising the necessity to maintain small scale mining and 'explores' its future 'prospects'.

Jan 1, 1990

By Kennedy G. L

Operating experience with the pilot Lurgi carbonization plant at Morwell showed that under conventional operating conditions, although the thermal efficiency of the plant was very' high, the physical quality of the char produced was extremely poor. By variation of operating conditions to produce the slow drying rate developed by the laboratory research at the University of Melbourne, an improvement in the size of the char was achieved. A similar approach in the carbonization stage where severe breakage of the briquettes still occurred was not possible due to insufficient control over the heating in this stage. Theoretical analysis of the heat exchange process has shown that severe heating of the briquettes entering the carbonizer is a characteristic of the Lurgi system and cannot be controlled by modified operation. The plant has been closed down for reconstruction of the heating system to enable it to be used to produce hard char.INTRODUCTIONAn experimental carbonization plant was operated at the Morwell Works of the 'Gas and Fuel Corporation from November 1958 until July 1959. This plant was built as a pilot plant by the Corporation to designs supplied by the Lurgi Gesellschaft fur Warmetechnik and had the nominal capacity to carbonize 25 tons of brown coal briquettes and to produce 11 tons of char per day. The briquettes were supplied from the· normal production of the Yallourn briquette factory and the 2t in. I-type briquette was the largest size which the plant could handle.This carbonization plant represents the intermediate stage of development between the laboratory research at the University of Melbourne and the commercial production of hard char as a metallurgical fuel. It is intended in the first place for the study of the technical problems in the handling and...

Jan 1, 1960

Study on Basic Theory of the Grain Settlement in Fluidised Bed This paper takes thick goal grains (less than 1.5 cm) as research object. According to different densities and particle sizes, thick goal grains are divided into 20 kinds of narrow density and narrow size level average grains. Free settling and hindered settling tests are respectively carried out in ?100 fluidised bed thick goal separators. Hindered settlement includes hindered settling velocity test and measurements of suspension density. Results show follows. (1) Fluid state in separator belongs to transition region. Alien's law is the appropriate formula of thick coal particles free settlement terminal velocity. (2) The main factors affecting hindered settling velocity are the number of solid particles in medium and the structure feature of the particle group. The bigger volume fractions of solids ? is, the smaller decreasing velocity coefficient of particle hindered settlement ¯ becomes. In the organism from bottom to top, density of suspended particles in fluidised bed gradually decreases, but near the top of the suspended particles, the density increased slightly. With increase of density and size, suspension density reducing extent increases from bottom to top of separators.

Sep 13, 2010

By M Pizey, M Kingsbury

Since 1950 Stockton Open Cast Mine has excavated over 60 million tonnes of Brunner Coal Measures overburden sandstones and mudstones. The current operator, Solid Energy New Zealand, recognises that acidic drainage from this overburden and from historic underground mines has led to depressed pH levels and elevated levels of metals in streams draining the Stockton Plateau. These streams report to the Ngakawau River. To quantify the effects of mine site acid drainage remediation/mitigation on the lower Ngakawau River water quality, a catchment hydrogeochemical model has been field calibrated and ecotoxicology tests have been undertaken. The hydrogeochemical model indicates that pre-mining and present pH values in the lower Ngakawau River are similar but present aluminium and iron concentrations are elevated. Ecotoxicology tests have semi-quantified the critical metal concentrations and interim water quality targets to achieve ecological recovery are presented. Analyses of long-term total suspended solids (TSS) and turbidity monitoring in the lower Ngakawau River and St Patrick's Stream indicate that TSS of 120 mg/L and turbidity of 20 NTU are exceeded for <20% per cent of the time. Hence, specific criteria to protect migratory native fish from turbid water are currently met in the Ngakawau River and St Patrick's Stream.

Jan 1, 2003

By H W. Wu

The objective of this paper is to examine some modern forms of auxiliary ventilation fabric ducting with streamline design fittings and the efficiency of construction practices. The most dynamic form of auxiliary ventilation is a moveable fan and ducting, which is easy to install and uses light weight fabric. The porous nature of some ducting construction results in leakage and loss of efficiency. Flexible fabric ducting is primarily associated with metalliferous mining and industrial material quarrying. Some applications are found in coal in stone/rock development and with use of dust scrubbers.Forcing auxiliary ventilation systems employing circular fabric ducting have been examined. Leakage of air from ducting is affected by ducting material and construction methodology (such as welded or sewn), quality of installation, number of joints, total length, pressure differences between the inside and outside and diameter. The best ducting system with welded construction can have up to four times less leakage as compared with some systems with sewn construction. It is also evident that the sewn type ducting will deliver less air to working faces and require more fan power, hence higher operating costs to run when connected to the same fan.A case study has also been undertaken to compare predicted operating costs of auxiliary ventilation systems connecting various types of ventilation duct fittings. The study also assesses the technical importance of streamline design with low aerodynamic resistance to reduce the shock losses of the duct fittings. It was found that the system connected with streamline designed fittings is able to provide some power cost savings and deliver more air compared with the system fitted with conventional fitting pieces.Using a ventilation ducting system with a lower leakage and frictional characteristic represents a sound solution to new challenges faced by the industry for increasing demand for better quantities and quality of air delivered to working faces; this is due to higher production schedules and stricter mine health and safety regulations within the Australian mining industry.CITATION:Wu, H W and Gillies, A D S, 2017. A comparison of auxiliary ventilation systems and their predicted operational performances, in Proceedings Australian Mine Vent Conference 2017, pp 207–214 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

It's long been suspected that there has been an increase in the incidence of premature failure of rock bolts in underground coal mines over the past ten years. As far back as 2002 a study found a possible contributor to such premature failure in some Australian coal mines might be linked to stress corrosion cracking (SCC) (Crosky et al, 2002). That study suggested the low impact toughness could be a major influence on the susceptibility to SCC of different steel compositions. A subsequent study involving laboratory corrosion tests however failed to confirm any link with metallurgical factors (Villalba and Atrens, 2007), a finding that is at odds with field experience. Some mine sites today are still reporting prematurely failed rock bolts to the rock bolt manufacturers; the failures are being identified at SCC induced. To this end a research project has recently been commissioned at University of New South Wales (UNSW), which aims to identify the environmental factors causing SCC, through field test sites and simulating the conditions within an accelerated corrosion laboratory. This paper outlines the methodology that will be used in this study.

Nov 25, 2010

Mineralogical analysis of a nickeliferous laterite from the Rockhampton region shows that the nickel is largely associated with the manganese wad and opaline silica. The laterite also contains an appreciable chromite content (about 12 per cent Cr2O,) although this tends to be poorly liberated.Leaching with hydrochloric or sulphuric acid, at atmospheric pressure at the boiling point is non-selective with respect to iron dissolution.The degree of dissolution increases as the acid concentration and retention time are increased; cobalt dissolution requires less aggressive conditions than does the dissolution of an equivalent amount of nickel.Leaching with sulphuric acid at elevated temperatures and pressures leads to a minimum amount of iron dissolution, is rapid, and requires a reduced acid addition rate. Nickel and cobalt recovery from the clarified leachate would be simplified because of the leach selectivity.Pressure leaching appears to be the most practical route for treating the Rockhampton laterite. The economics of processing would be made more attractive by the recovery of a chromium concentrate from the leach residue. This would typically contain about 45 per cent Cr2O, and could be used as a source of chromium chemicals.

Jan 1, 1986

The assistance that can be gained by the use of aerial photographs in the geological examination of a mineral field is clearly illustrated by the results of a rapid reconnaissance survey of the newly-discovered Mount Fitton talc, deposits, situated in the north-eastern extension of the Flinders Ranges in South Australia.The talc deposits were found to occur about the margins of a large lenticular mass of dolomitic marble, interbedded with hornfelsic tillites and fluvio-glacial sediments of Upper Pre-Cambrian age. Aerial photographs show clearly the extent of the dolomitic marble on which the growth of a species of eucalypt-Eucalyptus Gillei-is prominently developed, and which assists in defining the limits of this relatively light-coloured formation. (See Fig. 1).Upon field investigation it was found that the talc, deposits are related closely to the margin of the dolomitic marble where the latter has been subject to minor folding and faulting. The deposits themselves have been formed by metasomatic replacement of schistose dolomite. The contact of the dolomite with the underlying and overlying glacial beds is also noteworthy for the presence of minor occurrences of copper, silver, lead and zinc minerals.An examination of photographs covering a wide area reveals an outcrop of a massive granite to the north-east of the dolomitic marble, Fig. 2, which was almost certainly responsible for the regional metamorphism of the dolomitic and glacigene sediments, and the source of the mineralising solutions.All these features, as well as the broader structural features of the area, which are extremely important in the understanding of, individual commercial depQsits, were quickly determined with the assistance of the photographs.It is useful, briefly to relate the procedure adopted in examining this recently developed field as an example which may be well worth following on other fields, even if exposures are not so clearly defined. The method to be outlined, of course, will be of maximum advantage. Where rock exposures are good, where the ore bodies are likely to be widely spread, and where such bodies are related to some major geologi-cal control. Typical of such deposits are pegmatitic, hydrothermal and related ore bodies associated with the periphery of an igneous intrusion, or ore bodies related to particular sedimentary horizons in a regionally metamorphosed province.Procedure.The first requirement is the preparation of a detailed reconnaissance geological plan of as large segment as possible of the potentially mineralised province. The use of aerial photographs is par...

Jan 1, 1950

By Misra V. N, Cheng C. Y

Two types of Mt Tom Price hematite iron ore from Hamersley Iron P/L were tested using a Humboldt Wedag Jones P40 wet high intensity magnetic separator (WHIMS). The parameters tested were magnetic intensity (7000, 9000 and 11 000 Gauss), groove plate type (8R and 12R) and gap width (2.5 and 1.8 mm). It was found that at 9000 gauss magnetic intensity, reasonably high-grade and recovery in the concentrate were obtained. At 2.5 mm plate gap width, the 12R groove plate performed slightly better than the 8R groove plate. Further testwork is recommended to optimise the magnetic intensity, feed flowrate and pulp density, wash water pressure and flowrate with 12R and 8R groove plates at 2.5 mm gap width.

Jan 1, 1999

Tougher physical mining and processing conditions as well as economic circumstances are causing many mining companies to re-evaluate the effectiveness of their mine planning. The recent wave of inexpensive computing power provides the engineer an opportunity to go beyond the simple one-off manual mine design and production schedule. The basis of a good mine plan is a good reserves model. Concepts of mine model development are explored. The only advanced computer methods that have found consistent success in optimising mine planning functions are economic pit limits determination and material scheduling. Three pit 'optimisation' methods are examined; the moving cone, the Lerchs-Grossman 3-D graph algorithm, and the new network flow algorithm. A comparison between the methods in terms of total profits generated and computer time involved are made. The results show that both algorithms produced a higher profitability than the simple moving cone, but at much higher execution times. However, the profit increase never exceeded much more than 1 % of the base moving cone case. Finally, a method for the development of long range material production schedules with forward waste planning is presented.

Jan 1, 1989

For many years the scrubbing of roaster gas carrying sulphur dioxide has been carried out at the plant of the Electrolytic Zinc Co. of Australasia Ltd. at Risdon, Tasmania, using long horizontal tubes. in which the gas stream crossed a shower of water. In order to provide for increased roaster capacity, it was evident that additional gas scrubbing capacity would be required to prevent pollution of the atmosphere.This provided an opportunity to review the whole operation of gas scrubbing and an investigation was initiated to determine the characteristics of a counter-current type of scrubber. It was hoped that a change to this type of scrubbing would also reduce the sulphur dioxide concentration of the gas delivered to the atmosphere to a negligible amount. This, paper outlines results obtained from an experimental tower which was operated under a wide range of conditions, the packing height, gas flow, water flow, water temperature, and concentration of S02 in inlet gas being varied independently. A description is given of the leading features and operating characteristics of the plant units, which are designed on the basis of the experimental results. Operation of the new scrubbing system commenced on October 5th, 1948.THE PROBLEMThe gas which is handled carries S02 which may vary in concentration from 2% to 5%, and reaches the scrubbing system at a temperature of approximately 180 deg. C. An appreciable amount of suspended material accompanies the gas which has passed the cyclone system.

Jan 1, 1949

By Bujtor G. J, McMahon D. W

This guide to the understanding of ore reserve estimation is the revised version of a report with a similar title circulated within the CRA Limited (CRA) group of companies in mid-1980. It is the principal result to date of an Ore Reserve Study commissioned by CRA in late 1977.This guide to the understanding of ore reserve estimationis the revised version of a report with a similar titlecirculated within the CRA Limited (CRA) group ofcompanies in mid-1980. It is the principal result to dateof an Ore Reserve Study commissioned by CRA in late1977.The study was prompted by two ore reserve situations.The Zinc Corporation and New Broken Hill Consolidated,Broken Hill, had reached the point of havingto find a replacement 'for their traditional ore reserveprocedure and Mary Kathleen had to admit publicly thatore reserve predictions would not be realized. Thesewere not however the only problems to be looked at. Asmentioned more fully later, other ore reserve situationswere known, or were met during the study, in copper,gold and nickel as well, where poor realization: expectationratios had ranged from embarrassing to disastrous.These made it clear that ore reserve estimation had to belooked at afresh.The fresh look has resulted in a broadening of theconcept of ore reserve estimation from its traditionalpurely computational basis to an approach embracingall the many things that can affect expectation andrealization as essential factors. Hence this guiderepresents a gathering together of what has been learnedand what should be known to all those concerned withore reserves in any of its diverse aspects.The study has been marked"by a number of changesof thinking. At first the aspects that appeared to requireattention were two; recognition that an ore reserve statementwas an estimate, not a precise calculation; and asearch for im improved estimation procedure adapted tolow grade ores with narrow economic margins. Threeyears later the view was that the need was to incorporateinto ore reserve estimation all relevant aspects of theproposed mining operation from choice of a samplingmethod to sales contract specifications.This study is thought to be unique in being frankabout weaknesses in ore reserve estimation and intreating failures not as natural disasters (like drought orflood, which have to be endured) but as potentiallyavoidable. It has led to three principal conclusions.

Jan 1, 1982