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MR JOHN S Foxall wrote: Mr Clayton in his paper on the above subject (Proceedings, N.S. No. 34) made an assertion which should not be allowed to remain unchallenged. On the top of page 10 appears the following statement;- "By viewing the box at adepression angle of 45°, all the dimensions are disclosed and the box may be projected on isometric co-ordinates" and lower down on the same page:- "An isometric plan, being virtually a projection on a plane inclined at 45°, the nearer the dip approaches this figure so is the outline of the stoping more truly shown." Those statements embody an inaccuracy which would be misleading were an isometric plan to be constructed to suit a special case, ie the case of a mine whose lode dipped at 45°, or approximately 45° and it would be found that in such a plan the outline of the stoping would not be truly shown. The reason for this is that the depression angle at which an object is viewed in order to...

Jan 1, 1920

E Deposit is located at BHP BillitonÆs Area C iron ore operations in the central region of the Hamersley Province, Western Australia. It is hosted by the Marra Mamba Iron Formation, the lowermost unit of the Archaean to Lower Proterozoic Hamersley Group. Mineralisation at E Deposit East is contained within the Mount Newman Member of the Marra Mamba Iron Formation and extends into the lower West Angela Member of the overlying Wittenoom Formation. Use of a combination of geological and geophysical techniques has enabled the geological setting of the deposit to be qualified. Interpretation of detailed mine face mapping, downhole geophysics, geochemistry, geological logging and photography has identified D2- related thrust faulting, with substantial south-over-north displacement. Similarly, in-pit mapping at the nearby C Deposit has revealed intense localised D2 deformation, including overturning and thrust faulting. The interpreted structure illustrates that iron ore deposits in the central Hamersley Province can be intensely deformed and require detailed geological investigation utilising technical data from mapping and drilling to enable the creation of robust grade-models for the mining operation.

Jan 1, 2007

By M Thomas, S Lambert

The Tugun Bypass Tunnel in Gold Coast, Australia was constructed using diaphragm walls with the top-down cut-and-cover method to allow simultaneous construction of an airport runway extension above the tunnel, whilst excavation of the tunnel continued underneath. The tunnel was built in an environment of high groundwater table and deep deposits of alluvial and estuarine soils with the toes of the walls founded in soil deposits. There was a potential risk for differential settlements to occur between the diaphragm wall panels, caused by the runway fill placed over the tunnel roof during excavation. Dewatering within the diaphragm walls was required to facilitate the construction of the tunnel. The tunnel was also built in an area where environmental considerations were of great importance. Three-dimensional numerical modelling was undertaken to predict the differential settlements of the tunnel with considerations of varying subsurface profile, staged excavation and dewatering, non- uniform surface loading and complex soil-structure interaction. Field instrumentation and monitoring was implemented to confirm numerical predictions.  

Jan 1, 2008

By Szymanski J

In the first part of this paper, the principal sources of dilution during underground evaluation and mining are discussed, then definitions of ore dilution currently in use are analysed. These definitions vary depending on the authors. Ten different analytical expressions of dilution percentage currently exist. It is demonstrated, with the help of a numerical example for a given mining condition, that dilution percentage results vary considerably and that they depend on the definition used. This situation makes it difficult to compare different results regarding the dilution problem, often because some of the terms used are contradictory. A new ore dilution evaluation methodology is proposed, replacing the ten different analytical expressions by only two: the planned dilution factor related to the stoping selectivity, done at the mine planning level, and the additional dilution factor related to the efficiency of the dilution control measures during stoping operations. The conclusion shows that the use of this methodology would be a definitive asset in planning, in stoping operations follow-up, and in future costs comparison studies between mining operations.

Jan 1, 1995

The Pike River Coal Company is set to develop the Pike River Coal Mine in the Paparoa Ranges of New ZealandÆs South Island. The mine will be developed to extract a coking coal deposit of the Brunner Seam, some 46 km north-east of Greymouth, using a combination of continuous miners and hydraulic extraction.   The mining area is located within Department of Conservation (DOC) land and is adjacent to the escarpment of the Paparoa Range and the Paparoa National Park. As such, the major restriction to planned extraction is protection of:   +        the western escarpment, +        vertical and sub-vertical rock faces, +        permanent water courses, +        significant vegetation, and +        steep slopes.   The mine will use its elevation advantage to hydraulically flume coal from the working faces to the pit bottom area where it will be slurried to approximately 35 per cent density of solids and pumps down a slurry line to the coal prep plant some 10.5 km down the Pike River Valley. The coal will be sold on the export market as a high quality coking coal for international steel making.

Jan 1, 2005

The comparatively low winter rainfall, exposure to heavy salt laden coastal winds, and the consequent high evaporation rate, are important considerations in the rehabilitation of the Maslins Beach Sand Pit. The deficit of rainfall over evaporation is assessed at 1085 mm per annum. Such a coastal environment complicates the establishment of plants. The endemic flora found on the Sand Pit environs is mainly low wind-planed shrubs and mat plants. The dunes near the coast support an association dominated by Atriplex cinerea, Spinifex hirsutus, Scirpus nodosus, and Olearia axillaris. The coastal cliffs carry a more diverse vegetation dominated by Beyeria lechenaultii and Eutaxia microphylla. Overburden is used to develop a new landscape to screen operations, batter final faces, and cover rubbish at the nearby Council dump. The early overburden dumps were built with little regard for stability, but the more recent practice of using scrapers has resulted in more stable dumps. The erosion problems created by poor compaction have been controlled by contour banks, diversion drains, bitumen lined run-off drains, and hay mulching.

Jan 1, 1976

By Lloyd C. J

The uranium markets are at present well covered by available producers. However the predicted increase in demand, recently reinforc- ed by the Arab oil crisis, will by, the early 1980s'outdistance supply. Current trends are towards light water reactors with-fast breeder reactors not expected to make any significant impact to the mid 1980s. The proposed lifting of the US embargo on the use of foreign uranium in US reactors will expand the market available to non US producers. A balancing in supply and demand worldwide will probably occur in the early 1980s. Australia's potential producers at present hold about 20 percent of the worlds U308 resources. Three companies, have contracts to supply nearly 10 900 tonnes of U308 between now and 1986 which represents about 1 percent of the predicted demand to 1986. Australian producers need to establish themselves more firmly in the market place in order that other countries will not replace us. Contracts can be written now which will allow for world market prices to be paid in the future, thus protecting the Australian producer.

Jan 1, 1974

By Fisher AEJ

On Sunday morning 7th November, 1976, at approximately 2-25 a.m., smoke was discovered issuing from the 1912 m long belt drift at Appin Colliery. A Clouth steel cord rubber belt approximately 940 mm in width had been installed in the drift in 1963 on the basis that no fire resistant steel cord belt was then available to operate on a single lift at the load and on the 160 gradient of the drift. Investigation showed that the belt drift was on fire and the usually downcasting drift was upcasting. Immediate fire fighting and rescue operations were instituted and the drift was sealed off. High expansion foam was pushed into the drift from the surface and the fire was brought under control. Recovery work resulted in the fire being put out and the drift open for walking traffic by, S-P0 am., on Wednesday 10th November, 1976. lie experience gained during the fire fighting and recovery operations led to recommendations in regard to future use of high expansion foam.

Jan 1, 1981

A major problem in the continuous casting of aluminium killed strip steel is the incidence of black and grey lines in the strip surface caused by the alumina inclusions. One place for limiting the number of alumina inclusions is by providing favourable fluid flow conditions in the ladle so that the inclusions float out to the surface or adhere to the ladle wall. In laboratory equipment 20 kg of steel was melted in an alumina crucible of 14 cm diameter in an induction furnace. Deoxidation was carried out while the melt was constantly stirred by argon bubbling. Bubble frequencies were measured at the lance tip using a microphone technique. High speed cine photo- graphy was incorporated to measure melt top surface velocities. Experimental results indicate that the rate of removal of inclusions is a function of both the gas input and the power input. However due to unfavourable surface area to volume ratio, reoxidation of the melt took place. Some other experimental difficulties in working at high temperatures are also discussed such as lance design, melting arrangement and sampling techniques.

Jan 1, 1984

By Kyle J. H, Misra V. N

The recovery of copper from a flotation concentrate using ferric chloride leaching has been investigated. The concentrate from the Horseshoe Lights Mine near Meekatharra, Western Australia, contained mainly digenite, pyrite and talc minerals. Over 95 per cent of the copper was dissolved in an acidified ferric chloride solution in one hour at 70¦C and ambient pressure. The pyrite and gangue minerals did not react. The leaching process was found to consist of four separate reactions and the shrinking core model was used to describe the process. The effects of particle size, temperature, concentration of FeCls, stirring speed and leaching time on metal dissolution were investigated. The apparent activation energies in the second, third and fourth reactions of leaching of copper concentrate were 28.8, 11.9 and 53.9 kJ/mol, respectively. The optimum conditions for the leaching of copper from the concentrate, within the range of conditions studied were: particle size 63 per cent minus 38 ¦m, a ferric chloride concentration of 1.48 M, a temperature of 70¦C, and a stirring speed of 800 rpm.

Jan 1, 1991

By Griffiths J. B

From its mining lease at the northern end of Cohens Reef at Walhalla in the North Gippsland Mountains, the Long Tunnel Extended Gold Mining Company produced 13,695 kg of gold, which at 1980 prices represents a value significantly in excess of $200 million. In the period 1885 to 1908 the mine was one of Australia's principal reef gold producers, being top Victorian producer in six of these twenty-four years. Prior and subsequent occupants of the lease produced an additional 160 kg of gold. The Extended and the other mines on Cohens Reef whilst contributing importantly to the financial resource of Victoria, were the sole important support for the substantial town of Walhalla that had grown up around them. When the mines closed, Walhalla gradually reduced from a bustling developed town to the present attractive mountain village so favoured by tuurriSts. To allow the visitor to obtain a better ;ri.icrstanding of Walhalla's mining past, important parts of the Long Tunnel Extended Gold Mine workings and site are being

Jan 1, 1981

By Schofield N. A

The cross-sectional method of stope grade estimation at Cobar Mines has consistently had several shoneomings, me most imponant of which being mat stope grade is significantly overestimated in the high grade lenses.The use of mree-dimensional ore lens modelling improved the grade estimation and ore waste definition but significant overestimation still occurred in me high grade stopes, particularly those wim extremely variable grade distribution. The implementation of an indicalor kriging based method for mapping of me high grade copper mineralization has significantly improved the quality of copper grade estimates and provides a mineralisation geometry similar to that generated manually by me mine geologists. This paper presents the results of a test case study in the application of indicator kriging to the mapping of the copper grade in two stopes in the QTS North mineralisation. The results are encouraging in that they prov ide coofi rmation of the geometrical model developed by the geologists and much improved estimates of the grades of me stopes whencompared to me grade reponed from mining these stopes.

Jan 1, 1993

The nickel refinery at Yabulu consumes an average of 118,000 kg/h of low pressure steam in stripping operations to-recover ammonia and carbon dioxide from product liquor and ore tailings streams. The steam used in the stripping operations is produced from the 25 MW power generation plant at the refinery. The back pressure on the non condensing steam turbines is maintained at 60 kPa.Studies have been carried out to determine the optimum amount of steam required to be generated for stripping operations. When steam production is increased, the product liquor flow from thewashing thickeners can be increased. This results in improved washing efficiency of the thickeners and therefore improves the plant nickel recovery. A computer thickener wash model was used to predict nickel recoveries at varying steam consumption rates.The studies have shown that in most plant situations, it is not economical to-generate more steam than that already available from existing power production.The studies also highlighted the necessity to use all steam generated from power production at all times to maintain maximum nickel recovery.

Jan 1, 1985

Gravity concentration of tin at Renison Limited uses tables and spirals to treat the various coarser fractions produced from sulphide flotation tailing. An acceptable final tailing cannot be made from one pass over the tables and spirals and therefore the tailing from these separators is reground and combined with the sulphide flotation tailing as the feed to the classification section. The gravity section became increasingly overloaded in the years preceding 1976 due to efforts to maximize tin recovery to the gravity concentrate. In April, 1976, two 2DSV Reichert cone concentrators in series were installed to treat the table and spiral tail- ing stream, prior to regrind, to scavenge a small tonnage of hard, coarse low tin grade material for rejection to final tailing. Gravity section loadings were decreased markedly, allowing operator attention to be directed more to table performance than to spillage collection. An increase in mill throughput of approximately 15% was possible following the commissioning of the Reichert cones. The cones are currently operated to make the minimum tonnage of tailing consistent with reasonable- gravity section loadings.

Jan 1, 1978

Gravity concentration of tin at Renison Limited uses tables and spirals to treat the various coarser fractions produced from sulphide flotation tailing. An acceptable final tailing cannot be made from one pass over the tables and spirals and therefore the tailing from these separators is reground and combined with the sulphide flotation tailing as the feed to the classification section. The gravity section became increasingly overloaded in the years preceding 1976 due to efforts to maximize tin recovery to the gravity concentrate. In April, 1976, two 2DSV Reichert cone concentrators in series were installed to treat the table and spiral tail- ing stream, prior to regrind, to scavenge a small tonnage of hard, coarse low tin grade material for rejection to final tailing. Gravity section loadings were decreased markedly, allowing operator attention to be directed more to table performance than to spillage collection. An increase in mill throughput of approximately 15% was possible following the commissioning of the Reichert cones. The cones are currently operated to make the minimum tonnage of tailing consistent with reasonable- gravity section loadings.

Jan 1, 1978

By Wilson AF

Gold-silver mineralization at Cracow and Ukalunda in Queensland comprise quartz-filled veins, fissures and breccia zones hosted by propylitically altered volcanics and epizonal intrusions which are strongly fractured. The terrestrial volcanic facies, structural setting, type of alteration and complex mineralogy suggest these deposits are of the epithermal type.The 180 depleted character of the wall-rocks is consistent with the involvement of meteoric waters in convective hydrothermal cells associated with the vulcanism. The Cracow quartzes have remarkably low 6180 values from -2.0 to -3.4 per mil typical. of meteoric hydrothermal systems at high latitude, consistent with the inferred position of Australia during the Permian. 6180 values for the Ukalunda quartzes exhibit a wide range from 5.1 to 14.9 per mil which reflect the mixing of magmatic and meteoric waters, and a steep geothermal gradient.Further stable isotope and geochemical studies are in progress to establish the scale and morphology of the zones of anomalous 6180 and mineralogy in the wallrocks which constitute significant exploration targets.

Jan 1, 1984

In the extraction of level bridge pillars in the South Mine by square-setting methods the general practice is to work transversely from the hanging wall in narrow sections three or four sets wide to the depth of the bridge-usually three sets. When the working block attains an area of twelve square sets, sand filling is run in, either by pneumatic (Proceedings No. 123, 1941) or hydraulic methods, in order to control the settlement of the general area and prevent the development of undue weight in the stope. Upon completion of the filling operations, or coincident with them, ore breaking is resumed and the transverse section of the bridge pillar gradually reduced. A number of these parallel sections may be working at the same time.In preparing a block of sets for filling a great deal of paddocking is required, both to contain the filling and to preserve access to ladderways and ore chutes which may be situated at some horizontal distance. Stope paddocking until recently was constructed of 10 in. x 2 in. boards nailed...

Jan 1, 1942

Designing and constructing OxianaÆs Sepon gold and copper operations in one of the most remote areas in Laos has been a great achievement; one which was recognised by the engineering industryÆs highest accolade û the Australian Engineering Excellence Award in 2005. The developing nation of Laos has no previous mining or heavy industrial experience, but the support of the Lao Government and a remarkable Lao workforce has enabled the project to be developed and operate as well as it would anywhere else in the world.When making a decision to invest offshore, several geophysical and jurisdictional criteria need to be considered. Laos offers unparalleled prospectivity, a central location with growing infrastructure, a ready workforce and a developing but supportive regulatory regime. In addition, the Sepon copper project has exceptional characteristics, including its high grades, location near the surface, leachable qualities, access to hydropower and the ability to produce cathodes on site. These attributes and its location in the centre of a region hungry for resources contributes to the projectÆs excellent economics.

Jan 1, 2006

By C D. Ogg, P B. Pope, K M. Lynch, B K. C

Iron-reducing bacteria are able to couple the oxidation of an electron donor to the reduction of Fe(III) to Fe(II) under anaerobic conditions in the generation of cellular energy. Recent evidence suggests that these bacteria are phylogenetically diverse and widely distributed in nature. Our laboratory has isolated thermophilic, thermotolerant and mesophilic iron-reducing bacteria from numerous petroleum reservoirs with varying conditions, groundwaters of the Great Artesian Basin (GAB), and petroleum-contaminated soils. Some of these isolates have been identified as novel species and from genera such as Deferribacter, Bacillus, Alkaliphilus, Clostridium and Thermoanaerobacter. Further investigations have shown that these bacteria are metabolically diverse, not only capable of reducing different metal species but also able to use a range of organic compounds, including polycyclic aromatic hydrocarbons, for growth. Due to their abundance and metabolic capabilities, it is possible that iron-reducing bacteria may be important in microbially-enhanced oil recovery processes and in the bioremediation of contaminated soils and aquifers, particularly in anaerobic zones.

Jan 1, 2004

By Kewu W

Kaolin used as an industrial mineral, especially that in the paper-manufacturing industry, must be of fine size, with high brightness, a low impurity content, and good crystal shape. However, in most kaolin deposits there are various impurities which have a very bad effect on the quality of the kaolin. Therefore, it is necessary to remove these impurities from kaolin ore. Owing to their similar surface properties, the separation of kaolin and iron oxide minerals, especially microkaolin and iron oxide minerals, has been regarded as difficult. The iron oxide minerals often intergrow with kaolin in fine and complicated forms, such as thin films, which make separation difficult. In order to overcome this difficulty, many workers have suggested various treatment methods and obtained great success. Based on research work by Fuerstenau (1980), Huang, Li and Hu (1984), Hui and Wei (1991), Shergold (1978), and Zambrana et al (1974), we have investigated a two-liquid flotation technique for iron removal from kaolin and obtained some success.

Jan 1, 1993