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The coal basins that formed near the margin of Permian Australia were comparable in size with the Appalachian coalfields and with the European fields between Wales and Poland. They formed on the foreland side of a growing orogen in a system of linked transform basins formed by transtension on strike-slip faults. They were terminated and compressed when the Gympie volcanic arc was accreted to the orogen. Another huge system of Permian coal basins extending far inland from the Permian coast was also terminated when the Gympie Terrane was Accreted.

Jan 1, 1987

By Case JE

Complete Bouguer and isostatic anomaly maps compiled for Costa Rica provide new insights into the crustal structure and mineralization. Terrain corrections were approximated from the station to a radial distance of 167 km by computer using a 3- minute digital elevation model of Costa Rica and surrounding areas. Isostatic corrections, based on Airy-Heiskanen compensation, were also calculated from 0 to 167 km using the 3- minute elevation model and from 167 km to 180 degrees using combined topographic and isostatic reduction maps. Costa Rica can be divided into four main terranes based on gravity data: a Pacific coastal region, a Pacific inland area, a central region, and a Caribbean coastal region. Negative gravity anomalies along the Pacific coastal margin correlate with an offshore sedimentary basin, and large positive anomalies correlate with mafic and ultramafic igneous rocks on the Santa Elena, Nicoya, and Osa Peninsulas, and at Puerto Quepos. Pacific inland anomalies are separated from the Pacific coastal region by a steep gravity gradient, and over the Coast Ranges a major gravity low overlies a thick section of low- density sedimentary rocks. In the central region, a major gravity low occurs over a thick low-density Quaternary volcanic complex in the Cordillera Central, north of San Jose. A prominent feature of the Caribbean coastal region is an interrupted gravity low over the Limon Basin that reflects a thickening of low-density sedimentary rocks. A conspicuous gravity lineament, trending northeast separates northern and southern Costa Rica. The lineament is defined by the termination of several major gravity anomalies including those over the Coast Ranges, Cordillera Central, Puerto Quepos, and Limon Basin. In addition, the lineament correlates with other geological and geophysical data including: northeast-trending faults, the southern limit of large Quaternary volcanoes, the segmentation of the middle America volcanic belt, and a seismicity gap. This lineament may be the expression of a previously unrecognized major northeast- trending fracture zone in central Costa Rica. An important economic implication of the gravity lineament is a correlation with the termination of gold and porphyry copper deposits in Costa Rica.

Jan 1, 1987

By Irving R. C

THE objective of the iron smelter is naturally the production of high quality iron at the lowest practicable cost. To enable this, large tonnages are put through the blast furnace, and, at the same time, the quality of the iron must be under definite control.The modern blast furnace enables these objectives to be attained. The description whieh follows sets out the general details of construction of such furnaces, and the operation at thc Broken Hill Proprietary Company's blast furnaces at Newcastle, New South Wales.The occurence of iron in many forms is so well known as to need no description. Modern civilisation may be said to be built on a foundation of iron, and, today, the production of iron and steel has beeome one of the world's industries.A short historical introduction will serve to show the evolution of the processes and apparatus since iron production assumed importance.There is no definite date fixed as to when iron was first made, or by what means it was first discovered. Perhaps prehistoric man threw iron bearing stone on to his fire, and these became reduced, Ieaving a soft metal behind, or more probably the first iron was of meteoric origin.There is evidence, however, to prove that it has been known for a period of 6000 years. Iron has been found in the Pyramids and its use was known to the early Eqyptians and later to the Hebrews, Assyrians, Greeks and Chinese. Following the Greeks, the Romans excelled in its extraction and uses in the manufacture of their instruments of war, and to this fact can largely be attributed the success of their many wars of conquest. As the Romans overran the rest of the then known world they carried the art with...

Jan 1, 1930

By J Manuel, L Lu

Increasing bed depth is one of the main options sinter plants consider to increase production, since it is an incremental improvement and less expensive compared with a new plant. To maximise the benefits of increased bed depth, correct blend design and plant operation is critical. This paper discusses test work conducted to show the effects of ore type and bed depth on sintering performance and the adjustments required in both fuel rate and lime addition depending on ore type. The differences in sinter plug macro and microstructure were also examined to show the effect of bed depth on ore assimilation and matrix formation. Finally, the benefits of blending ores to achieve the best sintering performance as bed depth increases is discussed.

Jan 1, 2007

Computer-based block modelling of orebodies is now used at Renison Tin mine for the estimation of ore reserves. It is considered that this has resulted in improved reserve estimation for complex 'stratafault' orebodies. The results for all orebody types are more easily understood by the mine planning section and provide greater scheduling capability than those from the previous manual isoline reserve estimation method. A structural overview of the deposit can be gained by combining geological block models for the various orebodies. It is anticipated that upon completion of block modelling for all the orebodies the time spent on the annual ore reserve estimate will be significantly reduced.

Jan 1, 1990

Evolutionary changes to the original sizer concept are mild when compared to those which have taken place in the engineering standards embodied in today's commercially available machines. This paper examines the principles of sizer operation and reviews the development trends in new applications for this unique screen type.

Jan 1, 1978

Recent work on computerised mineral resource databases at the Institute of Geological and Nuclear Sciences Limited has concentrated on the development of the GERM, REGCHEM, and MINLIT databases, and their integration in a Geographic Information System using MapInfo software on an IBM-compatible microcomputer local area network. GERM (GEological Resource Map) is a mineral deposit inventory with national coverage and more than 10 300 entries. REGCHEM (REGional Exploration GeoCHEMistry) is a database of stream sediment analyses from open-file mining company reports, containing more than 14 000 sample sites from the Coromandel and west Nelson regions. MINLIT (MINeral LITerature bibliography) is an annotated bibliography of literature on topics relating to the exploration and geology of mineral deposits in New Zealand, and includes more than 5000 entries for published books and papers, and unpublished mining company reports, university theses, and government reports. Master sets of GERM and MINLIT continue to be maintained on a VAX mainframe network but REGCHEM is operated only in the PC environment using the Microsoft ACCESS database management system software.

Jan 1, 1993

By T Laurencont

The Queensland Department of Natural Resources and Mines (NR&M) accepted the environmental liability for the Mount Morgan minesite in 1991. This gold and copper mine located 38 km southwest of Rockhampton had been in operation for more than 100 years. Mining leases are still active while the feasibility of a reprocessing operation is carried out. From 1993, NR&M have operated a seepage interception pumpback system which has reduced the chronic load of acid rock drainage (ARD) to the adjacent Dee River, a tributary of the Fitzroy River system. In early-2000, it was recognised that a ten-year plan for rehabilitation of the mine, along with significant funding would be required if a long-term sustainable rehabilitation strategy was to be implemented at this minesite, ultimately making the seepage interception system redundant. A rehabilitation planning workshop coordinated by NR&M was held in May 2000. This workshop brought to the mine a range of technical expertise and key stakeholder groups. This workshop provided a technical forum for review of studies undertaken and to identify priority projects, which needed to be undertaken in the future to more clearly define contaminant sources on the mine site and to prioritise the rehabilitation program. Stakeholder consultation enabled the project team to be clear on community and other government (eg Environmental Protection Agency) expectations. It is clear that the future of the economically depressed community of Mount Morgan will be reliant on the careful management of the significant heritage values at the minesite for tourism, education and research. In the first year (2000), priority studies were initiated, which included whole of site studies on water balance, contaminant sources and a review of occupational health and safety and environment of the minesite and conservation and heritage scoping. Baseline vegetation and soil materials surveys were also initiated. The outcomes of these studies helped to shape the work program for the following year, while providing a basis for an additional funding application, which was granted. The second year of studies focused on building upon the existing baseline studies completed. In addition, studies focussed on addressing the priority issue of contingency planning for overflow from the open cut pit in accordance with best practice management of release water and river monitoring strategies were completed. Completion of these projects over the next six months will enable the optimal rehabilitation strategy to be defined in 2003. This optimal strategy may require the use of a water treatment plant for part of the ten-year program to provide space in the open cut pit for the deposition of ARD contaminant sources (eg waste dumps, tailings). It is envisaged that some sources will be rehabilitated insitu while others will be relocated to the open cut pit. Implementation of this strategy will be dependent on subsequent funding.

Jan 1, 2003

The investigations described in this paper aim at the development of a new impact mill. The objective is to produce particle size distributions below 10 .tm without using an air classifier. Circumferential rotor speeds of up to 200 m/s are strived for.

Jan 1, 1993

By Isobe K, Muchi I, Hsieh YS

Theoretical and experimental studies have been made-to clarify the physical and chemical behavior of the tuyere combustion zone of blast furnace. Gas streamlines around this zone were visualized by the use of the two-dimensional equip- ment. Close agreement between the observed stream- lines and the calculated ones is found. The three- dimensional experimental studies have revealed that there exists a so-called dry zone in the neighbor- hood of the raceway and the trickling liquid be- haves approximately like a continuum. A kinetic model is develdped to describe the behavior of coke combustion in the tuyere zone. The model is based on the reaction kinetics, the differential balances of heat and mass, and the mechanics of gas flows. Regarding-the-axial distribution of gas composition in the tuyere zone, good agreement is obtained be- tween the model prediction and the data observed in a working furnace by the other investigators. Cal- culated results-show that the maximum consumption of coke occurs at the intermediate region of the raceway. For the blowing of oxygen-enriched or high -humidity blast, the position at which the maximum consumption of coke occurs is shifted toward the tuyere nose. Similar effect is found when the par- ticle diameter of coke in the tuyere zone is de- creased. The solid flow pattern around the tuyere combustion zone was visualized by the use of the two-dimensional equipment in which the sublimation of dry ice particles in front of the tuyere was

Jan 1, 1981

The mechanisms of fragmentation in homogeneous materials and structured rock mass are reviewed. A method previously used to predict vibration damage to the remaining rock is extended and shown to be valid for the prediction of fragmentation in the rock mass removed by blasting. The effectiveness of different explosives in different types of rock blasting is discussed.

Jan 1, 1990

Previous studies on the blast furnace raceway zone have been undertaken at three levels of scale, namely: laboratory models at low temperature, hot models which simulate coke combustion in the zone, and tests performed on operating and dismantled blast furnaces. This paper reviews the results of this published work on raceways in order to illustrate the factors which affect the raceway shape, size and combustion characteristics. As a result of the work it has been established that raceways are influenced by blast parameters such as velocity, temperature and chemistry, as well

Jan 1, 1981

By OÆShea P. J, Dickson T. W

In April 1994 the Victorian Premier announced new State initiatives, collectively termed the Victorian Initiative for Minerals and Petroleum (VIMP), for exploration totalling $16.5 m over three years. The program, initially centred on the northwest of Victoria, the Eastern Highlands and the Otway Basin, is due for completion in June 1997 and has been designed to attract explorers to highly prospective but currently under-explored parts of the State. Major components of the program include acquisition of geophysical data (including airborne magnetics and radiometrics, gravity and seismic data), stratigraphic drilling, geological mapping and mineral resource data compilation. At the completion of the current program, 70 per cent of the State will have been covered by airborne magnetic and radiometric coverage at 400 m line spacing or better (Figure I) while 20 per cent of the State will have been covered by new geological mapping. The completion of database compilations for geochemistry, mine data and exploration licence summaries during the VIMP program is shown in Figure 2. The new airborne geophysical surveys have been flown partly under the VIMP program and partly by AGSO under the National Geoscience Mapping Accord (NGMA). Data from these surveys have been interpreted and incorporated into the geological mapping in order to enhance the quality of map products, especially in areas of Cainozoic cover. The first series 1:250 000 scale geological map coverage of Victoria was completed by the Geological Survey of Victoria (GSV) in 1977, and was based on compilation of historical geological mapping with minor field checking in most cases. The first metric 1:50 000 scale geology maps were also commenced in the 1970s, but were discontinued in the 1980s in favour of 1:100 000 scale map production. Driven by customer survey findings and with the benefit of detailed airborne geophysical data in the 1990s, the GSV reverted to 1:50 000 scale map production in 1995, with 1:10 000 scale maps made in areas of significant gold production. Geological reports still cover standard 1:100 000 scale map areas, but are now accompanied by four 1:50 000 scale maps. These new series 1:50 000 scale geological maps have been supported by comprehensive mine data and exploration licence summary databases in addition to the new geophysics, and benefit from the advances made in structural geological interpretation over the last decade. The new phase of geological mapping in Victoria, commenced under the NGMA in 1990 and accelerated under VIMP in 1994, has been focused in the central Victorian goldfields and eastern Highlands areas of the State (Figure 1). Results to-date have led to a number of major advances in the understanding of the eeoloeical evolution of Victoria.

Jan 1, 1997

By Eupene GS

The Early Proterozioc Pine Creek Geosyncline hosts a large number of gold showings. Mineralisation types include stratiform, synsedimentary deposits within iron formation and carbonaceous mudstone; disseminations in granophyric intrusives; and quartz vein related concentrations in the form of shear fillings, saddle reefs and stockworks. Stratiform gold deposits preferentially formed near penecontemporareous faults during periods of basin instability. Intrusive basic magmas later assimilated some stratiform mineralisation and subsequently redeposited it within differentiated phases. Gold was again remobilized during regional deformation and metamorphism. Stratiform mineralisation was upgraded insitu in high strain zones and gold was mobilized into metamorphic fluids. Fluid induced fracturing during prograde metamorphism and later uplift caused the deposition of extensive gold rich vein systems. The genetic relationship between gold deposit types is reflected in the clustering of showings along regional anticlines, and provides a powerful exploration tool. The large volume of 'exhalative'òmaterial in the Geosyncline with elevated gold content suggests significant economic stratiform mineralisation may be present, and probably provides a source for later disseminated and vein deposits.

Jan 1, 1984

By Kilgour I

The installation of a final cleaning column at Ok Tedi Mining Limited was carried out to increase final concentrate grade in order to reduce concentrate handling, shipping and treatment charges and to reduce penalty payments. To fast-track the project a decision was made to install a full-size column on one of the two parallel circuits, designed on information readily available and utilising the experience of mill staff and an engineering consultant, rather than delay installation while a pilot scale program was conducted. A 3.66 m diameter by 12.8 m high column was installed to produce 40 t/h of final concentrate from a combination of rougher concentrate and recleaner concentrate. The column design and sparger system were by Cominco Engineering Services Limited.

Jan 1, 1991

By Leach B. G

A geostatistical study was made of diamond drill hole intersections within 18CC stope block at the C.S.A. Mine, Cobar, N.S.W. The stope block is located in 18CC orebody which is a massive sulphide - multiple vein, Copper-Zinc type, lacking clear definition on gangue mineralogy, base-metal assays and total sulphide considerations. Of the variograms constructed for inter- section width and copper, lead and zinc grades and accumulations, only zinc displayed behaviour amenable to model fitting and kriging procedures. Zinc grades were calcu- lated for sub-blocks comprising the total stope block and comparison with equivalent grades determined by traditional methods showed them to be generally less extreme in the highest and lowest grade sub-blocks. The total-block grades derived by the two methods were almost the same. It is suggested that the failure of copper to show variogram continuity might reflect the difficulty in defining the actual 18CC orebody, a proposition which is supported by the poor continuity in the variogram of horizontal width. In the case of lead the poor continuity may be due to the frequent manner of occurrence of galena as coarse grained patches of limited extent. The results of the study, did not provide a convincing reason to depart from the traditi- onal methods of grade estimation at the C.S.A. Mine.

Jan 1, 1979

By G W. Scott, H M. Lukey

The Lake Superior Region has been a producer of iron ore for over 150 years. Early mining operations concentrated on direct shipping ores, which are the result of post-depositional upgrading principally by deep weathering. As direct shipping ore reserves became depleted, the focus changed to the production of iron ore pellets from taconite. The post-depositional processes responsible for upgrading taconite are regional metamorphism, contact metamorphism and hydrothermal processes (Clout and Simonson, 2005). While these processes are important in iron ore genesis they can also contribute to liberation problems and in some instances reduced pellet quality (Han, 2004). Low-grade metamorphic mineral assemblages can negatively impact liberation and pellet quality. Low-grade iron formation may contain a suite of carbonate minerals including ankerite, dolomite, kutnohorite, siderite and magnesiosiderite. Variation in the distribution and composition of siderite and magnesiosiderite makes controlling the MgO content of pellets difficult. Carbonate minerals also require calcination in the pellet induration process, which requires additional heat to be added to the system, slowing down the induration process and reducing throughput. Prediction of carbonate mineralogy and carbonate mineral chemistry is an important goal of ore characterisation for pelletising properties. Contact metamorphism causes changes in mineralogy and grain size (Klein, 1973; Gunderson and Schwartz, 1962). Increasing the grain size of magnetite should improve its liberation characteristics. However, plant grinding targets may not allow the coarse-grained, more easily liberating magnetite ores to increase throughput and can actually result in decreased throughput due to recirculation. While magnetite and martite ores are well understood (Lukey, Johnson and Scott, 2007) late open-space filling microplaty haematite ores are not. These ores, while composed of similar minerals, have a unique genesis that results in fine grain size and complex textures that present liberation challenges and often make interpreting laboratory metallurgical test results more difficult.

Jan 1, 2007

The Mount Sisa orebody on Misima Island, P.N.G., consists of goldsilver mineralisation associated with massive carbonate and amorphous iron-manganese oxides in fractures and breccia matrix. The orebody forms the northern extension of the Umuna deposit, which lies within a three kilometre strike length of a northwest trending, 300 metres wide, high angle fault zone. The structure is deeply oxidised, with the magniferous oxide material resulting from oxidation of carbonate. The wallrocks are metamorphosed basement psammopelites and basic volcanic rocks, extensively intruded by microgranodiorite. These are dominantly epidotised and sericitised. The precious metals are associated with anomalous Cu, Zn, Pb, Mn, As, Ba, Ga, Sb, and Mo. Many of the features of the Mount Sisa mineralisation are characteristic of volcanic-hosted epithermal deposits of western North America.Lithologic and textural gradation is observed between the carbonate hydrothermal breccia-fill at Mount Sisa, and the quartz dominated brecciafill and dilational fracture-fill mineralisation which forms most of the Umuna deposit to the south. This gradational relationship is analogous to that in the Amethyst-OH vein system at Creede, Colorado, where it is shown to be indicative of deposition from laterally migrating fluids.

Jan 1, 1988

Traditionally trucks have dominated haulage in open pit mines. Only recently have conveyors begun to be used in the long haul and high lift duties of surface mines. Steep angle conveyors are proven versatile systems for elevating or lowering materials continuously at steep angles to 90¦. This paper describes the design of a bucket-type steep angle conveyor that was developed as a joint research project between the Western Australian School of Mines and the Maanshan Institute of Mining Research in China. The steep angle conveyor can be used as a viable option for transporting blocky ore from open pit mines. A pilot conveyor was constructed and tested to determine its technical and operational feasibility. Furthermore, a computer model based on Matlab mathematical modelling software was developed to simulate the performance of the pilot conveyor. The model enabled to determine the design parameters of industry-scale conveyors to yield satisfactory performance. These conveyors become very cost-effective for those mines having large mine lives and depths greater than about 500 metres.

Jan 1, 2003

Underground space can be defined as space below natural ground level which can be used as an alternative to an above ground location. While many of our above ground structures inherently involve underground excavation for foundations and services, the term underground space specifically refers to organised development of underground openings and of the underground domain. For example, the services to a city such as power, gas, sewerage, water and communications are installed in a congested array which usually requires roads to be dug up when the services need to be accessed. An underground space installation of services would involve a well planned conduit which is easily accessed without any excavation. The concept of using this virtually untapped land resource to the advantage of our expanding cities is gaining considerable interest in Australia. Overseas, in the Scandinavian countries and some Asian countries, underground space has been used for centuries; in Great Britain, France and the United States of America over the last century and in Japan for over a decade. This paper focusses on the types of underground space usage which should be competitive with above ground use and suggests areas in which the competitive edge may be improved in favour of underground space. In particular, considerable advantage is seen by using well-planned underground space developments in major cities, where the strategic central location of the development takes advantage of proximity to potential users. However, the largest single factor affecting the acceptance of underground space is the high capital cost of construction, even though an underground space development may result in lower operating costs and reduced long-term maintenance costs. While excavation methods and associated costs are very much site-specific, the importance of applying the latest technology in rock breakage, with consideration of ground vibration, excavation rates and ground support, remains a major challenge to the development of underground space.

Jan 1, 1995