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By N J. Beukes, J Gutzmer, C Reinke, M Bau

In this study the light sparse phase search (SPL_Lt) mode on the Mineral Liberation Analyser (MLA) was successfully used to identify and quantify the abundance of rare earth element (REE) phosphates in Precambrian iron formations. Monazite (light REE phosphate) and xenotime (Y and heavy REE phosphate) are identified and data from the MLA combined with the mineral chemistry of the two minerals are used to calculate and model the expected REE concentration and distribution in these two REE phosphates. The REE phosphates account for up to 31 per cent of the REEs in the banded iron formations (BIFs) and excellent correspondence is observed between the modelled REE patterns and the whole rock geochemical data available for the same samples. Except for quantifying the mineral weights, the sparse phase search also allows for the localisation of REE phosphate grains and the observation of their association with other minerals using backscatter electron (BSE) imaging. These observations are used to conclude that the REE phosphates were most likely of diagenetic origin, with REEs and phosphate remobilised from primary chemical precipitates. It is demonstrated that automated mineralogical techniques can be used to qualitatively and quantitatively describe the influence of a rockÆs trace mineralogy on its geochemistry.

Jan 1, 2008

By Firkin GR, Allen RJ

Sulphide Corporation Pty. Limited has roasted a number of different zinc sulphide concentrates on its sinter machine which pro- duces zinc-lead sinter for an Imperial Smelting Furnace, and results have varied widely. The differences are considered to be functions of !concentrate particle size and reactivity. Amdel have used differential thermal analysis to examine these concentrates and two major effects have been found. Firstly, in concentrates 1containing small quantities of pyrite and chal- L [copyrite, heat is liberated at 400¦C to 650¦C [by oxidation of these two sulphides. Secondly, as particle size decreases, heat release from the oxidation of zinc sulphide commences at flower temperatures and rate of heat release In a sinter bed, the presence of some rite and chalcopyrite would help to heat the cc sulphide to ignition temperature in a orter time, while a finer concentrate would sult in roasting being completed more ickly. Both of these effects result in a arper flame front and minimise the chance heat and combustion fronts being mismatched. is theory is supported by sintering results tained by Sulphide Corporation. As a result

Jan 1, 1975

By Matsuo T, Uga Y

The tunnelling work to construct a sewage trunk line designed by the Sewage Bureau of Kobe City along north side slope of Rokko mountain range incorporated an all ground condition type (broad spectrum) TBM with slurry transport system with jet pump manufactured by Kawasaki Heavy Industries, Ltd. Boring dia. of the tunnel measured to 2.0 m. The construction planning and implemen- tation were done by Ohbayashi Corporation, the general contractor. The heading way was 3342.4 m in overall length.; construction work ran from April '84 to June '85. The max. daily progress marked 31.9 m and the max. monthly progress 493.1 m according to the relevant record. The machine proceeded with the work under geological conditions featured with conglomerate, rhyolite, tuff breccia and slate, whereby soft soil zone mostly of clay was encountered in a limited area. In the latter case, however, steel segments were substituted for supporting steel ribs. The tunnel was routed beneath a meandering road with the result that more than 40% of overall length show a curvature of 50 to 200 m radius.

Jan 1, 1987

I must tell you at the outset that I come to this conference deeply disturbed at the `role of Government in international dealings in mineral and energy resources'. I am disturbed by the confusion that now passes for policy. I am disturbed by the short- range view of critical problems taken by a majority of Governments. I am equally disturbed by the even shorter range of view taken by a growing army of industries. Many of them clamour for Governments to solve their problems in a specific way, with little regard for any other sector but their own-and with even less regard for the fact that every time a Government takes over some of their responsibilities they surrender some of their freedom. I would not say that longer range views don't exist. But I would say that they don't prevail at the present time. Instead, we are seeing the con- stant development of many policies for individual problems which don't tackle the fundamental causes. We must get back to basics without delay.

Jan 1, 1978

By Stone AM, Romensky G

The requirement for economic operation of unit trains carrying bulk materials has dictated that rapid and accurate bulk loading methods be provided. The train loading station at Phosphate Hill, built for Queensland Phosphate Ltd. to load rock phosphate, provides this facility and whilst the concept used is not unique, it contains a number of novel features that are considered to advance the "state of the art'' in this field. This paper briefly reviews some alternative concepts evaluated, and describes the design and operation of the scheme ultimately selected as being most appropriate to the project requirements. it is one which utilises a variable speed belt feeder whose speed is controlled in proportion to the weight rate of material moving on the belt as measured against a set point

Jan 1, 1978

This paper introduces a classification of gold orebodies, and comments on the importance of cutting high grade values, the choice of an appropriate ore reserve method and the necessity for producing recoverable ore reserves by considering the mining policy. The author stresses the importance of obtaining the appropriate information from the data relevant to a particular deposit as opposed to transfering parameters from one deposit to another.

Jan 1, 1987

Perhaps no aspect of the investigation of an ore-deposit is of greater importance to the mining geologist and engineer than a consideration of its geological structure. A thorough understanding of the type, size, shape, and arrangement of any ore-body is essential to the proper conduct of exploratory, developmental, and mining, operations. Significant as these remarks are' in relationship to ore-deposits in general, they become of paramount moment when a complex structure such as the Broken Hill Lode is in question. In this connection the use of the term "lode" as applied to the Broken Hill ore-bodies may terid to confusion of ideas among those not familiar with the field or with the literature pertaining thereto, by reason of the fact that it is generally understood that a "lode" is characterised by simple, tabular form, regular outline, defined walls, and persistent attitude. However, as the terminology is well established by common usage, itsretention appears desirable, and, for the purpose of this paper, the name "The Broken Hill Lode" refers to that complex unit which includes pre-eminently the famous ore-bodies exposed in the workings from the North Mine on the one extreme to the South Blocks (Zinc Corporation) Mine on the other.That the practical value of geological investigation, of the ore-bodies was realised by the Geological Sub-Committee of the late Scientific Society of Broken Hill is attested by the...

Jan 1, 1932

I am very grateful to have the honor of delivering this Key- note Speech to all of you here today, to the Chairman Mr Cope- man, and to all the organisers. As you heard, I was mainly involved for a very long time in the purchase of iron and steel raw materials for Nippon Steel Corporation. Today, however, I would like to talk to you about a much wider issue, namely, how the Japanese steel industry is going to change towards the 21st Century, and what will be the main technical innovations and trends behind those changes. I will also mention the effect that the changes are likely to have on the procurement of raw Materials.

Jan 1, 1988

Magnetic Separators have a wide application in dry separation processes, frequently in conjunction with High Tension Separation. Dry processes can frequently be superior to established processes in more commonplace mineral associations. A system of dynamics is postulated and the forces operating ar'e examined, together with a method of evaluating the effect of operating variables. Practical applications of these theories to obtain optimum results on an individual separator, and various separations using a laboratoryroll type separator are described.Practical Flowsheets are of two main types, the first consisting of a series of scalping operations, the second for rougher, cleaner, and scavenger operations with middling recirculation. Some common separation problems with certain mineral associations illustrate the need for different approaches for different mineral associations. A table of mineral separation characteristics is appended, from which amenability may be tentatively estimated.INTRODUCTIONMagnetic separators are widely used, either alone or in conjunction with other wet and dry concentration devices, for the upgrading of a variety of minerals. The high standards of efficiency attainable in dry mills, together with reduced operating and labour costs, are slowly becoming apparent in a wide variety of plants. The combination of wet and dry concentration plant familiar in beach sand mining is finding application for such processes as upgrading a crushed chromite product, and production of clean scheelite,cassiterite, and other concentrates. Other dry beneficiation processes (such as the high tension beneficiation of iron ore, and the benefiGiation of asbestos) avoid the use of wet processes completely.Dry separation processes are likely to be applied more widely as their possibilities become more generally known.

Jan 1, 1958

By Chia A. H

This paper presents an overview of the development and operation of the PT Adaro Indonesia coal mining project. This operation is an initial two million tonne per annum mine, located in South Kalimantan, Indonesia.The paper places emphasis on some of the more unique infrastructure development and operational challenges that exist in such a remote location environment.A brief summary is also given of the Indonesian coal industry, its direction and position as a significant coal producing competitor for Australia.

Jan 1, 1992

Gold Fields Ghana Ltd (GF Ghana) currently operates an underground mine at Tarkwa, in south--west Ghana. The mine was operated by Tarkwa Goldfields Limited, a wholly owned subsidiary of the State Gold Mining Corporation of Ghana (SGMC). The mine was making operating losses and in a poor state of repair. Tarkwa Goldfields retrenched all the staff and GF Ghana assumed management responsibility for its own account on I July 1993.

Jan 1, 1997

By A G. Pavlides, B L. Weekes

The Sepon Copper Project is located in the Savannakhet Province of Laos PDR and is operated by Lane Xang Minerals Ltd (LXML). An Ausenco - Bateman Engineering joint venture, the Khanong Development Group (KDG) managed engineering, procurement and construction of the project. The plant was fully commissioned in March 2005, two weeks ahead of schedule. The plant is designed to produce 60 000 tpa of cathode copper. The process flow sheet includes a pressure oxidation (POX) circuit that leaches pyrite flotation concentrate to generate ferric ions and sulfuric acid for use in atmospheric leaching of a predominantly chalcocite ore. The process is unique in that the chemistry in the autoclave is forced to produce a basic ferric sulfate precipitate for downstream recovery of ferric iron. This paper describes the design, construction and commissioning of the pressure oxidation circuit. The challenges imposed on construction and commissioning due to the remote location of the site, landlocked status and underdeveloped infrastructure in Laos are highlighted.

Jan 1, 2005

Methods of measuring the frictional properties of rock surfaces, both by direct sliding and in triaxial apparatus, are described. It was found that for some rocks the coefficient of friction remains reasonably constant as sliding is continued but for others it increases considerably.The effect of fluid pressure in the surface of sliding was found in all cases to be adequately represented by the effective stress criterion. Some observations on sliding on two conjugate planes showed that the motion on the two planes may be very different, depending on small differences in the constraints.The coefficients of friction of natural open joints in bore core were found to lie in the comparatively narrow range 0.32 to O.68 although surface coatings were very diverse.A set of diagrams on the equal area projection is given which enables a rapid determination to be made of those planes on which sliding is possible in a given three-dimensional stress field. The influence of the intermediate principal stress on this is of considerable importance.

Jan 1, 1969

By F Pothitos, S Hewson

The geological and geotechnical conditions at the Cadia Hill Open Pit are very complex. This complexity coupled with high mining rates has required significant technical input into the design and optimisations of the pit slopes, accesses, cutbacks and scheduling. A multi-discipline team of NML engineers, geologists and external consultants has been conducting comprehensive geological and geotechnical programs in order to achieve an optimum design of the pit slopes. Extensive data collection, analysis and interpretation has led to the formation of working geotechnical models of large structures, rock masses, and back-analysed slope performance charts. The current Cadia Pit Optimisation Project focuses on the risk-and-return principle for pit design and on the integration of geotechnical, hydrogeological, mining engineering and scheduling. The risk management for pit design has also been incorporated into the short term and long-term operation of the pit mining to ensure safety and production.

Jan 1, 2003

Australia had an active uranium mining industry in the 1950s with uranium oxide being supplied under contract to the atomic energy authorities of the U.K. and U.S.A. In the 1960s, when these con- tracts concluded, domestic production ceased, apart from Rum Jungle, whose production until 1971 was stockpiled. By the 1970s, the demand for uranium from the electrical utility industry had risen sharply and the effects on Australia were notable. The Mary Kath- leen mine re-opened in 1976 but, more significantly, exploration activity suddenly expanded with the re- sult that several world-standard deposits were locat- ed. Western world requirements for uranium based on increasing energy consumption and a changing energy mix, will warrant the development of Aust- ralia's resources. By 1985 our mines could be pro- ducing 9,500 tonnes of uranium oxide yearly and by 1995 the export value from uranium could reach that from wool. In terms of benefit to the community the economic rewards are considerable but, in terms of providing energy to the world, Australia's uranium is vital.

Jan 1, 1978

The Government Mining Engineer of South Africa has decided to legislate that Self Contained Self Rescuers (S.C.S.R.) become a mandatory piece of equipment for all those persons proceeding underground. It is envisaged that: * employees in underground coal mines will be fully equipped with S.C.S.R.s during 1988; * those persons employed in gold mines during 1988/89; and * personnel in all other mines by the end of 1990. It is the intention of this paper to discuss the introduction of these auxiliary life support systems, and to give an update on current market developments.

Jan 1, 1988

By Johnson RD

The variation in coal properties and the coal seam reduced level can be analysed using partial trend-surface analysis techniques. For the area studied seam reduced level and seam thickness data from the Bulli Coal yield trend-surfaces with a high coefficient of determination, since they have relatively small systematic local and random components in their overall variation. Sulphur content appears to have no significant re.gi_onal trend, and phosphorus content has a very weak regional trend. Other analytical variables have regional trends which are of intermediate strength. The strike-directions of.the statistically significant first degree! trend-surface are similar, sug-gesting.: that the variation of the several coal properties was controlled by a set of- related causes. The relations apparent from the dip and strike of the first degree trend-surfaces are similar to- those which are apparent from the trend- surface residuals and'from the results' of canonical trend-surface analysis.'.. It is probable that differential subsidence controlled the areal

Jan 1, 1975

In South African gold mines, the types of material requiring transportation to the stoping areas include timber packs, explosives, hydraulic rock props, scrapers, scraper winches, pipes, pumps and backfill material (in areas where backfill is being used). Currently timber packs are broken down to their basic components (log and brick) and are transported into the stope by means of either monowinches or a combination of monowinch and scraper winch. Other materials, such as explosives, hydraulic rock props, scrapers, scraper winches, pipes, pumps and backfill material must be transported by other means, usually by hand or, in the case of heavier items, by chain blocks. With the drive to increase stope advance rates and the rise in the number of miners with HIV/AIDS, there is a need in the South African gold mining industry for an improved material handling system. To meet future requirements, material handling systems should assist miners to transport materials quickly and efficiently. Furthermore, it must be financially viable and economically competitive with current material handling systems. This paper looks at the in-stope material handling efficiency of current monowinch systems and provides solutions to improve efficiency. In addition, the use of in-stope monorails are reviewed and the possible scenarios that will substantiate the use of monorail systems are discussed.

Jan 1, 2003

XstrataÆs Mount Isa Copper Operations (MICO) is a world-class mining operation producing in excess of six million tonnes of copper ore per annum from its underground mining operations. The Mount Isa Copper Mines have been producing from the underground operations since 1952. Current copper reserves are 87 million tonnes at 2.8 per cent Cu, extending the mineÆs life beyond 2018. The underground orebodies in the copper mines are divided into nine distinct areas and are mined by sublevel open stoping techniques. One of the nine areas is the hanging wall lens, which consists of two sections; a northern lens (NHWL) and a southern lens (SHWL). The SHWL has a proven reserve of 2.2 million tonnes with an average grade of 2.9 per cent copper. Stopes in the SHWL have an average size of approximately 245 000 tonnes and will be extracted in a primary-secondary mining sequence, producing ore until 2009. This paper discusses various aspects of stope design applied in the southern hanging wall lens, including sequencing options and the rationale for the selected sequence. Design features are also discussed and how they have evolved as more is learnt about the SHWL orebody. These include mass firing techniques, focusing on minimising ground vibrations, using seed wave form analysis and prediction. Rock mechanics issues will also be discussed, in particular the reinforcement of stope hanging walls and the use of instrumentation to monitor behaviour within the hanging wall.

Jan 1, 2006

By Veal FL

Technological changes in Portland cement manufacturing during past years have reflected changes in the economics and availability of various types of fuel such as coal, fuel oil and natural gas. The industry consumes a sig- nificant quantity of both thermal and electric- al energy. The nature of the process and its chemical constraints does however permit the use of comparatively low grade fuels such as high ash coal and high sulphur oil. In striving for increased daily kiln outputs and conservation of energy, there is a worldwide trend towards the use of dry process plants. Wet process kilns of about 2 500 tonnes per day assume massive component sizes which present difficulties in manufacture, and transport to plant sites. Large capacity dry process units in excess of 8 000 tonnes per day are now in operation using precalcination techniques in which part of the fuel is introduced in the static preheater section ahead of the kiln while the balance is added to the kiln in a conventional manner. This technique has virtually doubled the potential output of any given single kiln.

Jan 1, 1976