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By Brasnett TC

A wide variety of problems are encountered on a day to day operating basis in the Isa Mine Concentrators. These vary from complex textural problems in the lead-zinc concentrator and their subsequent effect on grinding and flotation to scheduling of converter slag treatment in a chalcopyrite concentrator. With the advent of process control, metallurgists need to specialise and keep up to date with technology improvements. This paper will attempt to describe the significant problems'faced by a Metallurgist û Control.

Jan 1, 1978

By Lewis PC, Carr GR, Dean JA, Glen RA

The Lachlan Fold Belt (LFB) is a complex orogenic belt which developed in Early to Mid Palaeozoic time. A number of orogenies and more localised deformational events affected the region. A simplified classification scheme for the diverse gold deposit types is proposed, subdividing primary mineralizing processes into four categories: volcanism (epithermal and volcanogenic deposits), igneous intrusion (subvolcanic/porphyry style, skarn and magmatic deposits), metahydrothermal processes (deposits generated during metamorphism and regional deformation) and hydrothermal-distal processes (deposits generated by poorly understood, generally remote large scale hydrothermal processes). Major gold deposit associations include epithermal and porphyry style deposits in Ordovician-Early Silurian shoshonitic andesite sequences; volcanogenic base metal-gold deposits in Silurian rift or basin felsic sequences; vein deposits in Late Silurian and Early Devonian S and I-type granitoids; deposits in Early Devonian sedimentary rocks of the Cobar Basin probably generated by metahydrothermal processes during basin closure and cleavage formation; deposits associated with serpentinite; and metahydrothermal quartz vein deposits in folded sedimentary rocks.Studies of host rock geochemistry suggest a relationship between magma types, gold enrichment and mineralization particularly in shoshonitic sequences and Early Devonian granitoids of the Boggy Plain Supersuite. Structural studies indicate the importance of thrust type structures and detachment faults in generation and location of gold mineralization. Lead isotope initial ratios help define metallogenic associations and a number of distinctive isotope "signatures" have been established.

Jan 1, 1990

As world demand for various minerals increases the mining industry in its endeavour to satisfy this demand will, eventually,look to the extraction of orebodies which previously may have been uneconomical to mine. These orebodies may be of two types. Firstly, new low grade orebodies and secondly, remnant sections of previously mined orebodies. Some of the factors relative to remnant mining operations are discussed and the potent- ial of remnant mining in providing an important contribution to future world metal production is considered.

Jan 1, 1975

A methodology is described to integrate heap leaching into a CIP operation. The paper firstly describes what is meant by a 'systems approach'. A broad view of the objectives of integration of heap leaching into CIP is given, followed by the components of the system, and then a description of the methodology for integration. The seven stages of integration are given as determination of distribution of gold, sampling, metallurgical testwork, conceptual study, pilot heap operation, pit modelling and pit optimisation. The final result is a series of optimised curves which determine the maximum value of the orebody, and the optimum cut-over grade from CIP to heap leaching.

Jan 1, 1992

New Caledonia, Norfolk Island and northern- most New Zealand lie on a long, narrow, ridge system, the Norfolk Ridge System, which is sit- uated in the centre of a geologically complex region of ridges and basins between Pacific Basin oceanic crust and continental crust of Australia (see Eade, 1987).

Jan 1, 1987

By Tronson K

Improvements in technology do not necessarily lead to higher profits: the benefit of lower costs can be captured by coal buyers, governments and workforce rather than by the colliery operators. The economic impact of longwall mining in Australia has been critically assessed to provide lessons for the future. For a variety of reasons, companies investing in longwall equipment in the past five years have generally not achieved an adequate return on the funds invested. The effect of technological innovation must be examined in the light of competitive forces operating in the market. Projections of cost reduction trends in the coal industry have been applied to a world cost model to provide a picture of the coal industry in the year 2000.

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

This paper will be a discussion of the geological exploration and drilling carried out on the Mt Davy Block, Greymouth Coalfield. A brief summary of the geology of the Greymouth Coalfield will be given to put the Mt Davy Block into perspective.

Jan 1, 1979

Utah Development Company operates a mine at Blackwater with a present annual production of 4 000 000 tonnes of coking coal. Mineable seams outcropping on the company's lease are part of the Permian Mammoth Rangal Coal Measures. Current operations are based pre- dominantly on the Main Lower seam. Coal quality variations occur along the seam strike, in the direction of seam dip, within the seam plies and in isolated anomalous areas. Raw coal of non-specification quality is washed to reduce ash and sulphur and to improve the free swelling index. Raw coal meeting specification quality is sent directly to product, by-passing the washplant. Careful attention to mining, coal preparation and product blending is necessary to ensure that the combined product meets specifications.

Jan 1, 1974

By C Gypton

This paper gives some insights into what to look for when reviewing feasibility studies. The review by a third party is an important element of the risk management process and may be the last remaining opportunity to uncover errors, or identify and reduce project risks on paper before they are converted to financial disappointments, steel and concrete monuments to process failures or cost overruns. The mining industry has had a spotty record in the area of estimating initial capital costs and operational performance, even though the standard of feasibility studies is generally acknowledged to have improved in the last decades. Third party reviews rarely have the luxury of enough time and unlimited funds, so where should the reviewers focus their efforts to be most effective? Assuming that the project already apparently meets investment criteria, the authors suggest where and how to look among fundamental project parameters for signs that serious flaws exist that have the potential to become project killers. We also give advice on how to review cost estimates without becoming lost in the details. The paper is supported with numerous actual examples.

Jan 1, 2003

Precious metal mineralization at the North Arm goldfield in SE Queensland occurs in the Triassic North Arm Volcanics, a sequence of andesite to rhyolite, pyroclastic and epi- clastic rocks deposited in a continental envir- onment. This unit displays a well-defined fracture system on Landsat imagery, including several arcuate structures which may represent former calderas. Two of the latter are associ- ated with zones of hydrothermal alteration, breccias and anomalous precious and volatile metal values. At the North Arm prospect, alter- ation is zoned from outer propylitic into exten- sive sericitic, although K-feldspar alteration is prevalent in the rhyolite. A zone of advanced argillic alteration is also present at Mt. Ninderry, SSE of North Arm. Alteration involves depletion of Na, Ca and Sr, and vari- able enrichment of S, As, Au, Ag, Hg and Mo. K and Rb are strongly enriched in K-feldspar altered zones. Precious metal mineralization occurs in veins, stockworks and hydrothermal breccia zones, and pervasive low grade Au-Ag dispersion is found throughout the sericitic and K-feldspar altered rocks. Veins and brec- cia interstices contain abundant quartz (common- ly banded), minor pyrite, calcite and sericite, with traces of silver grading to electrum, frei- bergite, naumannite, allargentum, marcasite, chalcopyrite and sphalerite. Mineralogical and geochemical characteristics are consistent with that found at volcanic-hosted epithermal precious metal deposits, particularly with the low-sulphur/adularia-sericite type.

Jan 1, 1987

The advantages of coordinate geometry in design and construction of underground works are apparent for reasons of flexibility, security, computer operations, survey error analysis, and the use of numerical techniques for setting out and checking works. Integration with National or State survey systems is useful in the long term, both at design, construction and future works stage. Equipment and methods are available which permit "absolute" monitoring of structures and strata over long periods,to close toler- ances. This work can be carried out in the limiting urban environment. Rapid data acquisition by semi-automatic devices, or photogrammetry, utilizing electronic data processing is capital inten- sive, but provides more data than analogue surveys (i.e., setting out centre lines) and becomes more attractive with increased labour Costs.

Jan 1, 1976

By K Friese, H P÷llmann

Clinoptilolites, modified with sodium, produced a material which has been tested for the ability to remove Hg (II) from aqueous nitric acid. The amount of adsorption depends on contact time, acid concentration of aqueous solution and initial mercury concentration. The study of the kinetics of mercury uptake revealed that all sorbents exhibit a fast rate of sorption. The highest sorption capacities were observed for sodium forms, and were up to five times higher than for the unmodified zeolite. The maximum sorption capacity toward mercury is determined as 0.093 ¦g/g at an initial concentration of 10.0 ¦g/L for a clinoptilolite from Tsagaantsav deposit (Mongolia). The sorption of Hg (II) has an ion-exchange nature and consists of three stages, ie the adsorption on the surface of microcrystals, the inversion stage and the ion exchange in the interior of the microcrystal. Sorption capacity decreases with the increase of mercury concentration. The presence of other metal ions such as Cd (II), Cu (II), Ni (II) and Zn (II) increases Hg (II) uptake capacity. Finally, sorption for Hg (II) was investigated in batch systems to evaluate the short-term stability of the sorption properties.

Jan 1, 2008

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

As you are all aware, the theme of this con- ference is "International Resources Management". The subject matter of this particular session is "the mineral equation". Looking down the sub- ject matters and individual papers to be presented by other speakers in other sessions over the course of the conference, each particular item scheduled is in fact one of the variables that form an integral part of the total and complex mineral equation. Questions of reserves and resources as related to consumption must be viewed in the light of all those variables. Policy decisions taken by Government and eventually industry in these various fields will in themselves have their own impact on the defining of resources, and their ultimate availability to meet the needs of society by way of consumption. Undoubtedly, by the close of this conference, those of us in attendance will be better informed on the problems that confront the international minerals industry in the years ahead. Hopefully, we will have a better understanding of the views and philosophies of the wide range of participants in the industry-Government, private enterprise, and individuals who ultimately through their per- sonal aspirations in respect of their day to day needs will provide the final determinant as to the scope of the minerals industry.

Jan 1, 1978

By Botz R. W

Macroscopic and microscopic studies of the outburst-prone Gemini Coal (Bowen Basin) showed that outbursts were associated with a localized inertinite-rich ply. Previous studies of the Gemini Coal had shown a general relationship between desorption rate, regarded as a good measure of outburst proneness, and inertinite content of coal samples.Desorption rates increased with increasing inertinite content and were highest for inertodetrinite-rich samples. These results suggest that inertinite content and composition play a significant role in outbursting and may be useful in identifying outburst-prone coals, which could be confirmed by desorption measurements.Consequently outburst-prone areas in the Upper Permian coal measures ofthe Sydney, Gunnedah and Bowen Basins have been defined using a combination ofthe parameters, inertinite content, depth ofcover and coal rank. In the Upper Permian, inertinite-rich coals are confined mainly to the top of the coal measures, except in the Sydney and Gunnedah Basins where an inertinite-rich interval (Bayswater Coal and correlatives) is also present towards the base of these measures. Only a small area ofthe central Sydney Basin, butmuch ofthe north-eastern and north-central part of the exposed Bowen Basin is considered outburst prone on the basis of these parameters.The most outburst-prone inertodetrinite-rich lithologies have a patchy and unpredictable distribution in the top of the Upper Permian coal measures. They can be defined only by sampling and petrographic analysis at the subsection level.

Jan 1, 1986

This paper describes how Western Mining Corporation uses sophisticated diesel equipment in mining of shallow flat dipping narrow ore- bodies in the Otter Juan area. Though in most cases the stoping method chosen relies on hand held conventional equip- ment, the 'ore handling systems have been designed to allow for a relatively high degree of mechanization. The use of diesel loaders, trucks along with three boom jumbos is described. A single one in nine decline driven as the means of access to the various ore surfaces at Otter/Juan resulted in the first ore being produced first 15 weeks after the first round was fired in the Ore-Decline. Now, three years later, the.mine is in full production, and in 1971/72 produced 392,000 dry tonnes of high grade Nickel Ore.

Jan 1, 1973

The U.S. Bureau of Mines has developed a prototype cross well acoustic logging system and complementary tomogr`aphic image reconstruction software for the detection and delineation of abandoned underground mines and associated subsidence failure in relatively shallow environments. The logging system uses a piezoelectric, cylindrical bender as an acoustic source. A triaxial accelerometer assembly, designed to be rigidly locked in the borehole, is the receiver portion of the logging system. Both the source and receiver probes operate at high frequencies, thus providing short wavelengths capable of resolving small features in most rock types. A modified van with a dual-drum wireline winch, 4-channel data acquisition system, power amplifiers, and waveform generator supports field operation of the logging system. A field study was conducted at a test site in San Antonio, Texas, to demonstrate the cross well acoustic logging system. The underlying rock at the test site is similar to stratified sediments in coal measures. First- arrival travel times were interpreted by tomographic reconstruction of the velocity field in the two-dimensional cross section between the source and receiver boreholes. The resulting image correlates well with geological borehole logging data for the test site.

Jan 1, 1992

By Wilkinson RDB, Van Der Meer FP

In order to overcome the statistical limitations imposed by the need to recover density tracers by hand, magnetic density tracers were developed to determine the efficiency of dense medium separators treating porous materials. The tracers were manufactured by extrusion of polypropylene ferrosilicon mixtures and subsequently coated with a distinctive paint to allow hand sorting according to density. Fifteen tracer batches were manufactured in the range 1.61 - 1.94 g/cm3. The tracer densities were determined by a hydrostatic method. The tracer method was applied to the dense medium separation of a Moroccan oil shale in a pilot scale Dyna Whirlpool separator. For each test, about 20,000 tracers were added with the plant feed and subsequently recovered from the products with a dry low intensity magnetic separator. The Tromp curve determined by conventional heavy liquid analysis was displaced towards lower densities compared with that determined by tracers, indicating that the porous shale particles absorb heavy liquid. It is concluded that for porous materials like oil shale and coal, the tracer method gives the most accurate results. In pilot scale testwork the tracer method is also much faster than the conventional heavy liquid analysis, as rather large samples have to be processed by the latter method to ensure Representativeness.

Jan 1, 1987

By Vidalinc, Raffoux

Longwall faces producing in the order of 20,000 tons per day of raw coal are presently running in the Houilleres du Bassin de Lorraine of Charbonnages de France. Production levels of twice that level pose some technical and economic problems of coal cutting, ventilation, coal and equipment transportation in the.face and from the face to the sur- face. The peak productions of the equipment in use today, the results of trials with new equipment, the utili- sation of forecasting models (some in the form of software), allow us to fo- resee feasable technical solutions to these problems. They will first be considered in the best possible context (thick- ness, dip, non gassy, soft coal, good strata, no faults). This will give. the necessary conditions to reach daily output'of that level. A sensitivity analysis of these- figures to the effective natural con- ditions will then be undertaken and the implication of such a project on health and safety (dust, climate ...) will be carefully considered. A concise technical and econo- mical approach will permit us to fore- cast the economical interferences of such production units and specially the consequences of sudden variations of the output (downtimes, failures, etc). From this investigation, goals for technological development and re- search areas will be outlined to be able to reach this production target in the XXIst century.

Jan 1, 1988