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The Circum-Pacific area is one of the most important gigantic skarn-metallogenic belts in the world. In more than 20 coastwise countries of this region, there exist thousands skarn deposits of different types. According to the differences of major metallic elements, the skarn deposits may be classified into seven subtypes, i.e. Fe, Cu, Pb-Zn, W, Sn, Mo and Au skarn deposits. In this paper, the distribution. and geological characteristics of above-mentioned types of skarn deposits are described briefly. Skarn deposits may also be classified on the basis of the dominant calc(magnesian)-silicate mineral assemblages into four types: magnesian, calcic, manganoan, and alkaline skarn types. Magnesian skarns may be associated with Fe, Cu, Au,, Sn, B, Be mineralization, calcic skarns with Fe, Cu, W, Mo, An, Be, Pb, Zn, Sn minerailization, while the alkaline skarns occur in U(Th, Nb) deposits. The skarn deposits of both East and West Pacific rims have many general characters, but have some diferences in geotectonic settings, intensities of mineralization, distribution, and metallogenic epoches. In this paper, the minerogenetic series and the mineralizing specialities of related magmatic rocks of the skarn deposits are also discussed.

Jan 1, 1990

An improved method of sample recovery for use with rotary percussion drilling has been developed. Cuttings can be recovered continuously from either dry or wet drilling, and the recovery under dry conditions is seldom below 99% of the cuttings brought to the surface by the rig. The system is designed for use with top drive drilling rigs using flush-jointed drill rods. The key feature of the system is a self-aligning mechanical seal around the drill rods. The sealing unit is removably fixed to a collar section of cas ing. the cuttings are recovered in a plastic bag attached to the bottom outlet of a cyclone. A valve at the bottom of the cyclone permits the cuttings representing various depths to I,e recovered separately for examination eind 0(iclysis. [u the Iron Monarch quarry, two percussion holes were drilled to depths if 30 metres and 28 metres using the unproved sample recovery system, and diamond drill holes bored 1 metre from each percussion hole. Samples from each hole were sectionalized over metre intervals and analysed for iron, silica, alumina and loss on

Jan 1, 1976

Uranium minerals were found in Australia as early as 1869, but it was not until the 1940's that a search specifically for uranium was begun. Instrument types and techniques used in early exploration are still used today, but have been developed into more sophisticated and portable types. Recent improvements in exploration have been the introduction of the gamma ray spectrometer, radon sampling and geochemical surveys. The environments of presently defined uranium deposits are predominantly sedimentary. Known deposits in igneous environments are usually small. The size of targets which are likely to provide economic deposits is of the order of 10,000 tons U308, producible at a cost of less than $10 per pound. Such targets are most likely to be in Precambrian sediments or in granitic masses. Recent exploration in Australia has included investigation of Precambrian sediments, Precambrian and Palaeozoic granites, Mesozoic and Tertiary sediments, Precambrian volcanic rocks and brecciated masses of unknown age. The origin and method of emplacement of uranium in these environments is not well known but there are indications that syngenetic sedimentary processes are important, and volcanic rocks may make a major contribution to the supply of uranium.

Jan 1, 1970

The T33-34 blast, the first major blast at Mount Isa Mines, broke 1,360,000 tonnes of copper ore using 349 tonnes of explosives. The original concept of firing T33, T34, T35 and U37 separately was changed during the life of the project due to adverse ground conditions. These conditions also caused the stoping method to be modified after the firing of the stopes had started. To stabilise the two stopes T33 and T34 where large fall off was occurring, rib pillars were left in the original slot. This caused the blast design to be more complex as these rib pillars had to "lead" the blast. The implication of such a large blast on the underground and surface environment was thoroughly investigated and precautions taken. The charging time of the blast was six weeks. Hook-up was started four days before the blast and continued until two hours prior to the blast. Detailed scheduling was carried out of other work that had to be done in the 24 hours before the blast to ensure that there were no delays in the firing.

Jan 1, 1977

By M Spagnolo, M Ashley, D, L Reemeyer

PasmincoÆs Century Concentrator in North West Queensland commenced operations in November 1999. The nameplate production capacity of 500 000 tpa of zinc metal production in concentrate was achieved in August 2002. Completion of the production ramp up was successful due to the culmination of a number of initiatives throughout 2001 and 2002. Mine to mill interaction to understand and eliminate head grade related bottlenecks affecting Concentrator production and reduce feed variation. Grinding circuit process development û operating and process control strategies to improve stability and reduce grind size to support zinc recovery. Pumping upgrades to control spillage in ultrafine zinc flotation Low density zinc flotation strategy û to improve silica-sphalerite separation to improve zinc recovery while maintaining acceptable silica in final concentrate. Flotation circuit process development û froth crowders, froth cameras and reagent control strategies to improve primary zinc flotation performance. Review and implementation of longer campaigns between planned shutdowns to improve availability. Team reorganisation û to improve setting and implementation of metallurgical strategies. This paper describes these initiatives and their contribution in achieving the production target. It also notes the ball mill motor failures that delayed the successful achievement of the ramp up, and CenturyÆs response to minimise the production impact. The paper also outlines the capital improvement program that was implemented to improve zinc recovery to design 82.5 per cent recovery once the production rate had been achieved.

Jan 1, 2003

By M A. Noppé

"Investors and other stakeholders assessing the risk, opportunity and relative value associated with a resource project need to appreciate the project in its correct context. Errors, omissions, biased reporting or conflicting information in project reporting may lead to a misinterpretation of technical and financial results, resulting in biased estimates or assumptions on project value.This paper provides a simple ‘Resource Project Framework’ for presenting a project’s status that may be readily benchmarked against other similar projects and to illustrate the stages required to advance the project outcomes to higher levels of certainty. The framework draws on definitions and guidelines readily available in various resource industry reporting codes and public company reporting requirements.The framework assesses three key areas for placing a resource project in its correct relative context, namely:the project development stagethe confidence in the Exploration Results, Mineral Resources and/or Ore Reservesthe level of accuracy, precision and confidence in the technical and economic studies supporting the reported results or options for the project.The application of the Resource Project Framework is illustrated using two project examples, one from publicly reported company project releases and the other for two development projects.CITATION:Noppé, M A, 2016. A framework for presenting and benchmarking resource projects, in Proceedings Project Evaluation 2016, pp 260–274 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016

By T D. Jolly, L A. Balzan, A R. Harris, Z Bauk

"The availability of real-time data in any process control system is critical for effective management of that system. At MMG LXML Sepon Copper Operation in Lao PDR, controlling the copper grade of the feed to the leaching circuit is paramount for maximising both productivity and copper recovery. Since 2008, real-time analysis data has been available to the process engineers from the Geoscan on-belt analyser installed on the Copper Mill feed conveyor, and highly accurate results on copper grade have allowed the process engineers to strictly control blending to overcome the variability in plant feed grade. The availability of real-time analysis data is crucial, as effective sampling of this stream is both difficult and error-prone, being only a snapshot in time of highly variable ore stockpiles, as well as having significant laboratory turnaround delays. Periodic sampling is used to verify the Geoscan data as accurate. Since its installation, the copper result has been the most critical output of the Geoscan. In recent times, the process engineers have sought to utilise other results from the Geoscan to further improve and control the process. One measurement of particular interest involves the real-time measurement of calcium and magnesium as a gauge of ore feed gangue acid consumption. To satisfy this end, accurate measurement of calcium and magnesium is becoming increasingly more important and has been the subject of ongoing collaboration between Sepon and Scantech, the manufacturer of the Geoscan. This paper discusses this work, describing the calibration process and results obtained, while also providing a basis for Geoscan use in operations to enable enhanced process control for all potential Geoscan users.Citation:Balzan, L A, Jolly, T D, Harris, A R and Bauk, Z, 2016. Greater Use of Geoscan On-belt Analysis for Process Control at Sepon Copper Operation, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 231–238 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

Conventionally, a combined system consist- ing of a dry or wet pulverizer and kneading mac- hine is applied to the pretreatment of fine mat- erials for agglomeration, especially for pellet- izing. However, treatment cannot be expected to be satisfactory owing to the complexities of the process. A new process was developed to over- come the defects inherent in the conventional process. This new process treats certain fine materials having a moisture content somewhat lower than that suitable for pelletizing in a ball or rod mill. The mill is of special de- sign in which grinding and strong kneading are performed to give an extremely homogeneous ball- ing material with appropriate size distribution and pelletizing characteristics. The most serious problem in this process is the choking of sticky materials in the mill. A specially designed rubber lining was installed in the mill to overcome this trouble. This paper presents actual results from our iron ore pelletizing plant relating to the pelletization of other fine materials.

Jan 1, 1974

By George G

The Circum-Pacific Map Project is a cooperative international effort to prepare and publish geological, geophysical and mineral resource maps of the Pacific Basin and adjacent land areas. Earth scientists representing 180 organizations from more than 40 Pacific Rim countries are participating in the work. The project is directed by a committee established 14 years ago as an activity of the non-profit Circuin-Pacific Council for Energy and Mineral Resources. Technical and cartographic support is provided by the U.S. Geological Survey. The Circum-Pacific Map Project is organized under five regional panels of experts on the geology and resources of the four quadrants of the Pacific and Antarctica. A series of five 1:10,000,000-scale regional maps and a 1:17,000,000-scale map of the entire Project area, the Pacific Basin Sheet, provide the cartographic base. Forty-eight individual sheets are planned and thirty have been published in eight different series, including base maps, geography, plate tectonics, geology, energy resources, mineral resources, tectonics and geodynamics. Additional special single-sheet thematic maps on the Pacific Basin base have been published and are planned for a total of more than 50 individual sheets.

Jan 1, 1987

Zinc concentrates from the newer mines and from proposed developments provide both opportunities and processing challenges to the conventional roast-leach electrowin smelters. These concentrates are often characterised by low iron, elevated silica, possibly high manganese, and levels of elements such as germanium which may cause concern. In addition, environmental constraints on residue disposal are forcing significant changes to some smelter practices. Iron in concentrate, and the resulting environmental impact of residue disposal are now major questions. However, normal concentrate tariff structure provides a disincentive against smelters taking high grade concentrate and oxide fume. Processing technology to cope with these changes is reviewed, as is de-watering and materials handling of ultra-fine concentrate. Within a few years, such fine concentrates will account for up to 1 000 000 t/y of contained zinc. New processing technologies including novel transport methods, siliceous leach circuits, manganese removal cells and front-end smelting will become significant in zinc smelting.

Jan 1, 1993

Ranger Uranium Mines Pty. Ltd. operates an open pit mine and ore treatment plant in the Northern Territory designed to produce 3 000 tonne/yr of U308 in yellowcake from 3 500 tonne/day of mill feed. The construction of this project was completed in 1981, 12 years after the discovery of the orebody. Wright-Davy, a Joint Venture of Wright Engineers and Davy McKee Pacific, were the Project Managers and Designers of the $270 million ore treatment plant and associated infrastructure. The project was designed in Sydney in -an office integrated with the Client, staffed by 35 key personnel drawn from Wright Engineers and Davy McKee, supplemented by personnel hired for the project. The peak Wright-Davy workforce in Sydney of 200 contained 113 design staff. The design principle of using the best practicable proven technology resulted in a plant which easily produces its design output using ore types outside the design criteria. The structuring of the project systems and industrial relations policies contributed to construction being completed within time and under budget. The plant was built without any major industrial dispute occurring and no dispute arose due to the uranium issue.

Jan 1, 1983

By Alesse V, Belardi G

A new class of collectors, Mercapto-Benzo-Oxazoles (MBO), exerting selective action on copper sulphides in the presence of Pb, Zn and Fe sulphides (galena, sphalerite and pyrite), has been synthesised in co-operation with Enichem's Donegani Insitute. The collectors have a mixed aliphatic-aromatic structure and contain functional groups which form chelates with copper. Some reagents of this class having hydrocarbon chains of various lengths have been laboratory tested on a complex sulphide ore containing chalcopyrite, galena and sphalerite in pyritic gangue. Comparative flotation tests have permitted selection of the best collector for chalcopyrite, namely Methyl-Mercapto- Benzoxazole (MMBO). Systematic flotation tests have been performed with this reagent, varying collector concentration, grain size of the feed, pH and flotation time. The results obtained show that the synthesised collector is much better than potassium-amylxanthate (KAX) as regards selectivity towards Pb and Zn. Moreover, it is possible to work at natural pH (6-7) and the flotation rate is higher. In fact in the rougher stage with 80 g/t of collector at natural pH, a copper grade of 7.14 per cent was obtained with a recovery of 73.87 per cent, while the grade with KAX did not exceed 2.11 per cent for a recovery of 73.54 per cent. The amount of Pb and Zn reporting in the copper concentrate was eight per cent and ten per cent respectively, while with KAX it was no lower than 24.34 per cent and 22.71 per cent in that order. After two minutes flotation a copper grade of 5.2 per cent with 52 per cent recovery could be attained, against a grade of 2.5 per cent and a recovery of 44 per cent in the case of KAX. The efficiency of this new collector has been ascertained on two samples of complex sulphide ores of diverse mineralogical composition.

Jan 1, 1993

Historic mining across the Bendigo goldfield reached an average mining depth of 750 m over an area of about 16 km by 4 km, with two shafts exceeding 1400 m. Mining ceased in the mid 1900s due in part to increased dewatering and ventilation demands. Water extraction technology of the day, combined with multiple mine ownership, did not allow uninterrupted and thus economic mining activity to prosper. Today Bendigo Mining Limited (BML) is targeting gold-bearing reefs beneath the water-filled historic mine workings. To ensure mining activity can proceed without the risk of water inrush, historic workings are being dewatered by submersible pumps in historic shafts and through a series of underground drain holes intersecting old workings. Due to the high heads involved, individual drain hole development requires rigorous safety control implementation and assessment prior to drilling. Water extracted via drain holes is pumped to the surface through a series of pipe lines and rising mains in conjunction with two staged pumping stations. Both stations are equipped with high-speed centrifugal pumps, each capable of pumping 40 L/s at a static head of approximately 300 m. BML, which operates beneath and within a large city, is confronted with unusual environmental and social challenges compared to many within the mining industry. The raw mine water, which contains elevated salt levels, is piped through residential areas and must comply with strict controls to prevent impacts on the surrounding environment. The final delivery point is BMLÆs water treatment plant at the north end of the city. The water treatment plant utilises chemical pretreatment and reverse osmosis. It is able to process 7 ML of mine water per day at full production. The product is approximately 5 ML of reusable irrigation quality water, which is made available to the Bendigo community for public gardens, sporting facilities and rural irrigation. The 2 ML of brine is directed to a purpose-built evaporation pond facility located 7 km north of the water treatment facility.

Jan 1, 2008

By D A. F Oliveira, C J. Parker

The role of the virgin in situ stress field in tunnelling projects is well known in the Sydney area. The effect of in situ stresses is mostly considered through the use of published relationships that describe the in situ stress conditions as a function of depth. Considering the significant scatter in the data, it is evident that by adopting such relationships, the designers are assuming an average distribution of stresses with depth that is generally a reasonable engineering approach; however, when building a geomechanical model, the tunnelling or geotechnical engineer needs to account for the interrelationship between ground conditions (rock mass quality – fracturing, strength and stiffness) and in situ stress, which may explain part of the stress data scatter. This paper presents an alternative approach for interpreting in situ stress conditions, valid for both Sydney sandstones and shales that focus on such interrelationship between in situ stress and ground conditions.CITATION:Oliveira, D A F and Parker, C J, 2014. An alternative approach for assessing in situ stresses in Sydney, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 189–194 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Hall S. F, Quast K. B Newell R, Ketteridge I. B

For the past six years research funded by the State Energy Research Advisory Commit- tee of South Australia has been conducted at the South Australian Institute of Technology, School of Mining and Metallurgy on South Australian lignites. A major part of this work has been a study of the potential bene- fication of Bowmans lignite using hydrometal- lurgical techniques. The Bowmans lignite de- posit is the largest of its type in South Australia and is a major energy reserve for the state. The utilization potential of this deposit is reduced by its very high insitu NaCl content which presents serious problems for any process. Previous research conducted by Readett and co-workers (1984a & b) has shown that NaCl is amenable to extraction using simple batch water leaching operations. This leaching has been successfully described using a two stage diffusion model derived from first principles based on a simple diaphragm cell.

Jan 1, 1987

By T Akiyama, J A. de Castro, H Nogami

Blast furnace is a countercurrent moving bed reactor that produces pig iron from iron bearing materials like pellet, sinter or lump ore. The furnace has cylindrical shape and the lump solid materials are alternatively charged onto the top of the furnace. Hot air is introduced through tuyeres that are set on the lower furnace wall. Auxiliary fuels (pulverised coal, oil or natural gas) and raw materials (fine ore or fluxes) are injected into the furnace with blast air from the tuyeres. In front of the tuyeres, coke particles react with oxygen in the blast air and generate carbon monoxide. The hot reacting gas heats up the lump solids and reduces iron oxides in the upper furnace. In the middle height of the furnace, the reduced iron and slag are fused by the combustion heat and form the cohesive zone. The molten iron and slag that are generated in this region trickle down through the packed bed of coke particles and flow into the bottom of the furnace. Therefore, the flows of gas, lump solids and liquids exist at the same time in the lower part of the blast furnace.

Jan 1, 2000

Distillation of the large and growing greenhouse literature indicates that: ò Global warming has occurred over the past century or more; ò Build-up of CO2 (and lesser greenhouse gases) in the atmosphere is a fact; ò This build-up is likely to cause further global warming. It does not appear possible to conclude that the observed C02 build up and observed global warming are linked; nor is it yet possible to forecast global or regional climate variation with conviction. The dominant greenhouse gas is C02 with about half the warming potential of those gases emitted by man's activities; and about 80% of anthropogenic C02 emissions are from the burning of fossil fuels. Fossil-fuel C02 emissions arg divided about equally between the developed countries of OECD and the rest of the world. However C02 output growth over the past decade was about 4% for OECD and some 40% elsewhere. Population growth and pressure for better living standards will ensure continued higher growth outside OECD. Uncertainty about the impact of increasing C02 emissions on climate, and the long lead-times involved in limiting the increase in atmospheric C02 concentrations, are good reasons for taking action now. Australia accounts for about 275 million tonnes a year or just over 1% of the CO2 emitted from the world's consumption of fossil fuels, and the fight to control global emissions will be won or lost elsewhere. Australia's participation will be by wise conselt and by example. In view of the uncertainties involved, it appears premature to take actions that might place an additional financial burden on our hard-pressed country. However, much can be done now that makes good economic sense and has the added benefit of limiting the growth in Australia's CO2 emissions. Natural gas emits less C02 per unit of energy when burned than either coal or oil. Furthermore, new gas-fired power stations utilise energy at considerably higher efficiency than is the case today with coal or oil. Because of much lower capital costs, there is a compelling economic case for permitting natural gas to compete freely with coal in the Australian power generation market.

Jan 1, 1989

By D M. Aranha, A R. Cabral

Theories on the origin of the Itabira iron formation (itabirite) in Quadrilßtero Ferrffero (QF), as elsewhere in the world, are restricted by the apparent lack of adjoining volcanic units, severe syndeformational metamorphism and deep weathering. Besides the three types of iron formations at QF (siliceous, dolomitic and amphibolitic; Dorr, 1969) we include a fourth type initially described as ocherous, goethitic, limonitic or even yellow iron formation. Considering its high magnetite content, it has been described as yellow magnetite itabirite (Pires, 1979). It was reported as formed by the alteration of the dolomitic itabirite (Dorr, 1969) although the anomalous Al2O3 contents are high for normal weathered itabirite. The yellowish magnetitic itabirite occurs at the bottom of the Itabira Iron formation, along the contact with the Batatal schists, and at the top units of the Itabira, within the Gandarela Formation. Within the magnetitic itabirite at the Tamanduß iron ore mine there are metric zones, concordant to the bedding of pillow-like structures, exhibiting a porous core, surrounded by an intermediate, more granular zone with numerous, minute rounded cavities grading to an external, fine-grained zone with much less minute cavities. In the external portions of some pillows a breadcrust type structure, derived by quenching with the water can be observed. In some other zones, such as the Barreiro hill, an outer, vesicular, whitish yellow, 5 - 10 mm thick, band grades to an aphanitic, isotropic band. The vesicles are slightly flattened against the band surfaces. The existence of fragmental layers showing flowage and fragment alignment, kaolinitic laminas and vesicles filled with kaolinite at Barreiro Hill and Capitpo do Mato Mine represent mesoscopic structures, indicators of a possible volcanic origin. Chemical compositions of the magnetitic itabirite from a wide area in QF revealed a relatively high Al2O3 content, consistent with a volcanic origin.

Jan 1, 2005

By B Menzel, M Wlasenko, J Phillips

Yandicoogina (Yandi) open pit mine is located in the eastern part of the Pilbara region of Western Australia. It hosts pisolitic iron-oxide mineralisation distributed within a meandering paleoriver channel. The deposit is characterised by clays occurring as lenses, accretions, desiccation joint infill and voids in the pisolite ore. The irregular shapes and highly erratic distribution of these clay pods represent a serious challenge for grade control at this mine.The current grade control approach used at the Yandi mine is based on sampling of production blastholes on a 6 m X 6 m spacing. Their good spatial coverage, tight spacing and low cost make blastholes a very convenient media for grade control and ore-waste definition. However the potential downside of this grade control approach is poor sample representivity. An alternative grade control approach is to drill and sample using reverse circulation (RC) holes distributed on a 25 m X 25 m grid. This approach has been tested in Yandi mine and compared with the blasthole sampling approach for sample representivity. The impact of increased drill spacing on mining block predictions has been studied using a conditional simulation technique. Blasthole and RC samples proved to be similarly biased, underestimating Al2O3 and SiO2 grades and overestimating Fe grades, when compared to full cone assays. These results show that using RC drilling for grade control at the Yandi open pit will not necessarily improve the representivity of the grade control samples. However, increasing the grade control spacing to 25 m X 25 m will lead to more than 12 per cent of the selective mining unit (SMU) sized blocks being misclassified. This is approximately a two-fold increase in the number of misclassified SMU blocks in comparison with 5 m X 5 m spacing.

Jan 1, 2007

By A Bossilkov

Although environmental and sustainable development reporting has now become widespread in the Australian mining and minerals processing sector, there remains a great deal of diversity in reporting contents and practice. Moreover concerns remain about the effectiveness of reporting for delivering the companyÆs business case for sustainable development as well as for communicating sustainable development performance to a range of external stakeholders. This paper therefore reviews the status of sustainable development reporting in the Australian minerals processing industry. Pertinent international and national developments are briefly captured, leading to a discussion of the framework for integrating sustainable development reporting with sustainable development management (as proposed by the World Business Council for Sustainable Development). This leads to a discussion of the results of a comparative review of sustainable development reports of a cross-section of eight Australian resource companies. Best practice elements are highlighted in regard to reporting on company context, governance, performance and assurance.

Jan 1, 2004