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By Peck WH

For many years it was realised that the methods used for unloading concentrates at Port Pirie were inefficient and labour intensive, therefore, when a decision was reached to standardise the east-west rail link from Sydney to Perth, the opportunity was taken to consider entirely new schemes for the handling of concentrates at Broken Hill and Port Pirie. After considerable testing and investigation, it was decided to install a completely new concentrates handling plant incorporating a tippler at Port Pirieòto replace the previous long established methods of unloading and dis- tributing concentrates to the operating plant.and the shipping berths. To achieve this, wagons of concentrates from the various mines are marshalled in a set order at Broken Hill and conveyed to Port Pirie in 56-wagon trains. On arrival at Port Pirie, the wagons are checked and moved to a position where they come under the control of the automatic wagon marshalling equipment.

Jan 1, 1975

The unique chemical and physical properties that can be displayed by polypropylene and its copolymer derivatives are enabling its development as a truly versatile material for water filtration. Well known applications include spiral wound cartridge filters commonly used for household water or the office drinking fountain, to pressure membranes that provide micro, ultra or nano size filtration barriers, whilst needle-felt or woven cloth filter belts or inline pressure bag cloths are well known to the hydro metallurgist and process engineer. A relatively new filtration concept that is generating interest and applications across all industries including the mining sector involves use of a unique fabric type filtering media made from polypropylene fibres. This technology not only has a vastly wider window for potential applications, it delivers an attractive cost saving alternative to the traditional sand media or diatomaceous earth type filters, along with potential benefits for integrated filtration units. This paper discusses the proven potential of the fabric media technology with examples of performance comparisons and confidence gained from full scale operating installations at mine sites and other locations.

Jan 1, 2004

The collapse of the I.T.C., the subsequent fall in the price of Tin, and the lifting of quotas saw the Renison concentrator resuming full seven- day operations at maximum capacity in 1985/86. Performance was sus- tained in terms of grade and recovery, and in some areas improved, over this period. A further challenge was declining head grades, and the need to treat higher proportions of less amenable ore types. The complexity of the flowsheet and the method of mining and ore handling predisposes the process to unstable operation, and solving this problem comprises a major component of the current development effort. The concentrator has an imbalance of capacity between processes, and excess in some areas is being adapted to enhance the capacity of others. Magnetic susceptibility of various minerals is being exploited to greater effect. Significant performance gains are achievable by improving exist- ing unit process efficiency, particularly in grinding, gravity processes and Cassiterite Flotation. This paper reviews the metallurgical developments, both recently implemented and planned for this year, which have contributed to main- taining Renison Limited in a competitive position in the post I.T.C. Tin industry.

Jan 1, 1988

In south-eastern King Island, sediments and lavas of possible Upper Proterozoic to Lower Cambrian age have been intruded by Lower Carboniferous granitic rocks.Within the contact aureole of the Bold Head adamellite north of Grassy the sediments and lavas have been metamorphosed to hornblende hornfels facies grade. The thermal gradient within the contact aureole was small, as the hornfelses exhibit no mineral zoning over a distance of 700 ft from the adamellite.Skarns occur both within the adamellite near its contact with the country rocks, and within the country rocks as partial replacements of three dolomitic limestone horizons. The latter type, the exoskarns, commonly have an andradite-salite mineralogy and carry economic concentrations of scheelite. These resulted from the replacement of carbonate beds due to both diffusion and infiltration metasomatism. Silica, tungsten, minor sulphides, and water were introduced from the adamellite, while aluminium and iron diffused from the enclosing pelitic sediments. Calcium released during marble replacement countered the loss of iron and aluminium in the pelitic hornfelses transforming them to diopside-rich rocks.Endoskarns within the adamellite are the result of two way diffusion across the contact; calcium, aluminium, and iron diffused from sediment to adamellite as silica, potassium, sodium, and water diffused from adamellite to the sediments. From estimates of the lithostatic pressure and mole fraction of CO2, the mineral assemblages of the hornfelses imply that the temperature of metamorphism lay between 530° and 710°C. This temperature range is in good agreement with minimum temperatures, between 610° and 710°C, for the recrystallization of the marbles of the contact aureole, calculated from the determinations of the solid solution of the magnesite molecule in calcite.

Jan 1, 1971

The mathematical modelling of rock fragmentation by blasting is one of the most difficult and challenging problems of applied mathematics. Not only is complex mathematics required but there is incomplete understanding of the basic physics and chemistry involved. The possibility of getting the physical basis of a model correct by simple mathematical and experimental procedures is demonstrated for the novel process of fragmenting rock by high-pressure arc discharges. While the importance of obtaining the correct physical basis for a model is emphasised, high-pressure arc induced fragmentation of rock is shown to be a powerful laboratory tool for the study of blasting.

Jan 1, 1990

By Cutler JL

At the present stage of the Rundle oil shale project planning, with depressed world oil prices, early development of the resource is unlikely. However, this postponement is being used to carry out technical studies required to evaluate alternative rehabilitation strategies and establish a sound environmental planning basis. Major technical data from the following studies are reviewed: Resource: - mine planning; material characterisation; retorting; geology; Environmental: - meteorology; surface water management; laboratory and field leachates; revegetation; waste characterisation; hydraulic and chemical modelling; dust suppression; plant/water interactions; and impact evaluation. These studies have shown that topsoil replacement, seeding mixtures, fertilizer application rates, subsoil quality and handling, waste pile slope and most importantly soil water storage are key factors in successful rehabilitation.

Jan 1, 1987

By M Coulthard, J Rivalland, K Dugan

Prior to 2001 Yallourn Mine has pumped approximately 1000 Megalitres of water per annum from aquifers beneath the mine floor in order to control aquifer pressures that were thought to have an influence on mine floor and permanent batter stability. In 2001 one of the deep aquifer pumps was shut down for five months in order to measure the aquifer recoveries. Prior to the shutdown a UDEC model was created in order to predict what level of recovery in the aquifer pressures would be critical to mine stability. The shutdown showed that the aquifer levels recovered and stabilised at levels that did not threaten the stability of the mine. The aquifers recovered to levels below the critical levels identified in the UDEC model.

Jan 1, 2003

By Fermino R

Reduction of waste oxides from steel plant operations was investigated in a laboratory tube furnace at different temperatures and furnace atmospheres. The results have shown that the waste oxide pellets are reduced rapidly to very high degrees of metallization irrespective of the furnace atmosphere and that the reduction is simultaneously accompanied by significant low- ering of the original impurities. It is shown, for example, that treatment at 1000¦C for 30 min. can reduce the Zn content from 0.98% to 0.0065% and K and Na contents from 0.19% and 0.76% respectively, to less than 0.01%. However, pellet strength at 1000¦C was low but this, as shown in the paper, can be very significantly improved by treatment at 1250¦C. The results indicate that the reduction of the waste oxide pellets of this investigation proceeds almost certainly by a chain reaction mechanism and that this principle could be advantageously extended to the reduction of iron ores and other oxides in general.

Jan 1, 1984

By G J. Corbett

Magmatic-related low sulfidation hydrothermal ore systems at plate margins exhibit distinct spatial and temporal zonations which can be used to aid mineral exploration and development. Low sulphidation systems at all crustal levels exhibit the same paragenetic sequence of events: early breccia formation, followed by quartz - secondary feldspar sericite/illite veining, then mineralisation, and final argillic overprint. This sequence of events is interpreted to reflect the initial emplacement of melts at high crustal levels, and the progressive cooling of that melt and release of magmatic constituents into a circulating hydrothermal system.   Low sulphidation systems in the south-west Pacific region exhibit a vertical zonation in deposit types: from porphyry copper-gold at deep levels, quartz-sulfide-gold at mesothermal to deep epithermal levels, carbonate-base metal gold at mainly epithermal levels, and epithermal quartz silver-gold at shallow levels. It is interpreted that the characteristics of each of these styles of deposits is produced by mixing with circulating waters of different physio-chemical compositions.

Jan 1, 1995

The results of the washing of coal are often presented by using Partition Curves. By analogy, it is possible to express the results of screening by using similar partition curves. As in the coal washing processes, this method determines the accuracy of screening and is also suitable for different separations depending on the difference in size distribu- tion. This method compares the effectiveness of two screening operations and forecasts the performances.

Jan 1, 1984

Scheduling the transformation of in situ coal to run of mine coal and its subsequent beneficiation to a saleable product involves the use of many `parameters' or `adjustment factors'. These include in situ density, moisture adjustments, mining

Jan 1, 1998

By Moore A. J

Control of blast vibration requires that its nature and causes be understood, and that effective control procedures be implemented to ensure compliance with limits related to the probability of damage to buildings/structures and human discomfort. This paper covers measurement equipment, assessment and prediction techniques, blast vibration control procedures and applicable statutory limits. It reviews current practice, and provides information on recent developments in blast vibration measurement equipment and control techniques, using examples based on Hunter Valley mining practice.

Jan 1, 1995

By Bangerter PJ

The use of gravity concentration is, and has always been, the conventional primary method for gold recovery from alluvial deposits. The development of high capacity cone concentrators and metallurgically efficient wash-waterless spiral separators has had some impact in the technology for alluvial gold processing, but perhaps more significantly has led to the relatively recent use of this gravity concentration technology in grinding circuits of hard rock ore for "coarse" gold removal and for scavenging gold locked in sulphides from cyanidation tailings streams.Gravity concentration systems are relatively low-cost, non-polluting and energy efficient; and their judicial use in gold treatment plants can significantly reduce overall capital and operating costs.The application of modern gravity concentration technology to hard-rock and alluvial gold ore treatment is discussed. Flowsheets and test and operating data from a number of gold processing operations incorporating gravity concentration treatment are presented.

Jan 1, 1984

By Nolan D. P, Balales M

Over the last two years work has been undertaken within the Pasminco Metals - BHAS Zinc Plant to improve the efficiency and maintain the production capacity of the operation. The work has centred upon the installation of suitable process instrumentation to improve process control and the development of new unit operations to maintain control of the circuit water and sulphate balance. A key aspect of the new process instrumentation has been the development of an on-line analyser to monitor the total antimony concentration during zinc dust purification. As a result of changes made to the Zinc Plant in order to contain all effluent within the circuit, a problem developed with control of both the water and sulphate balance of the circuit. A new neutralisation plant to treat all cell house waste water so that it can be contained within the circuit has been developed and installed. In addition changes have been made to the existing circuit to control deliberately the circuit sulphate concentration by precipitation of sodium and potassium jarosite.

Jan 1, 1993

By Moort van J C

A new low-intensity magnetic separator which operates by spinning particles in a continuously rotating magnetic field is able to reduce particle entrapment of non-magnetics to an almost insignificant level. In such separators the removal of ma

Jan 1, 1997

By G Giles

One of the main tools used by mining operations to mitigate the risk of rock burst is the installation of a so-called ædynamic resistantÆ support system. Such systems are designed to absorb the impact of shockwaves created by mine-induced seismic events. Dynamic support must be strong and capable of sustaining high loads and, at the same time, they have to be flexible and accommodate large deformation. A dynamic support system is therefore a system capable of absorbing a high quantity of energy. Ground support systems are composed of rock reinforcement (rock bolts or cable bolts) and surface support (mesh or shotcrete). In terms of surface support, fibre-reinforced shotcrete is increasingly seen as the industry preferred solution when difficult ground conditions are experienced, including areas of high seismic hazard. A thick layer of shotcrete is certainly strong but it is by no means flexible. Normal weld-mesh has some flexibility, but it is not very strong. The Australian Centre for Geomechanics (ACG), in collaboration with Onesteel Reinforcing Pty Ltd, is currently working on a new high-energy absorption mesh that combines strength and flexibility. The new mesh can be installed with a jumbo, in a similar way as the widely used sheet of weld-mesh. This paper describes the development of this new mesh system.

Jan 1, 2008

By P Andrieux

By 1996 ground control-related problems at Brunswick Mine had raised serious concerns regarding the safe and economical extraction of large portions of the reserves. These difficulties were mainly caused by high stress levels in pillars, instabilities resulting from wide spans supported by ageing support elements, and chronic difficulties supplying rock fill from the surface quarry to the underground workings, which resulted in many large voids remaining open for long periods of time. Significant changes have been implemented at the site since 1996, amongst which were a change of mining method, the introduction of paste backfill, the establishment of stress management measures, and the introduction of shotcrete on a large-scale. This paper focuses on the regional ground conditions associated with both the previously used primary-secondary mining method and the newly implemented pyramidal pillarless technique, as well as on some of the stress management measures implemented at the mine.

Jan 1, 2000

Commencing early in 1975, Saraji Mine in Central Queensland will product 3.56 million tonnes in the first year and then 4.57 million tonnes annually for the Japanese and European markets. The coal will be mined from a series of pits separated by corridors which will be mined at a later date. Through the corridors flow regional drainage structures and power lines. Relatively easy areas will be mined initially to assist the cash flow and to minimise start-up difficulties. For ease of scheduling it is desirable that pit lengths exceed 3 000m but this will not always be possible. Ramps were designed using 1 200m spacing and 5 per cent gradient as optimum but modified to suit specific conditions. One ramp will be in the end of each pit nearest the ROM hopper and stripping will commence from this end. The advantages so gained are shorter haul distances, immediate access to the coal after stripping and simplification of the excavation of the first ramp. Haul road location was defined by the minimum present value of construction plus operating costs. Road design utilised airfield construction charts because wheel loads were outside the range of available road design manuals. Low load resistance characteristics of

Jan 1, 1974

Sampling criteria and practical implementation of these criteria are discussed with a view of achieving and maintaining a high level of quality for minerals at their various stages of production through to their utilisation. From this it will be shown the advantages that can be gained by producers who undertake stringent quality control programmes for their ores, thus ensuring they have a competitive edge over other producers.

Jan 1, 1985

Intermontane valleys form unusual features of compressive mountain belts both in the sharp topographic break they represent and in the strike-slip displacements often associated with the valleys. Such strike-slip motion seems hard to reconcile in the actively deforming Andes where reconstructions have indicated nearly perpendicular Cenozoic plate convergence. Detailed study of a part of the Argentine Andes between latitude 31-33¦S suggests that, although strike-slip displacements may have largely created a prominent intermontane valley system, no Holocene strike-slip displacements are observed amid the relatively active compressional deformation along the mountain belt flanks. New plate reconstructions, treating the Nazca plate as two microplates separated by fractures along the Nazca Ridge, predict large components of strike-slip motion between the South American and Nazca Plates for the period from 10 to 5 Ma. These reconstructed plate motions are consistent with strains derived from recent kinematic analyses of minor faults along the southeast margin of the Puna plateau and the general timing of tectonic phases in the Andes.

Jan 1, 1987