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Aluminium in Australia, and in fact all round the world, is made virtually exclusively by the Hall-Heroult process, whereby the metal is derived from the electrolysis of alumina dissolved in an electrolyte comprising fluoride salts. It is the distribution and control of these inorganic fluorides during and after the reduction process which go to make up the bulk of environmental problems associated with aluminium reduction smelters. The emission characteristics of fluorides from the process, the occurrence and effects of fluorides in the environment, and the control techniques wnich are applied in industry, all need to be taken into account in assessing the overall environmental aspects of aluminium Production.

Jan 1, 1977

The Permian coal in the Muja Coal Measures of Collie Basin of Western Australia has a subdued lustre because of the fine laminations of lithotypes, and the dominance of dull and dull banded lithotypes with minor bright, bright banded and fusinous types. The maceral composition of the coal is variable, however the macerals of vitrinite and inertinite groups dominate and the exinite and mineral matter contents are low. The lithotypes have low concentrations of trace elements and the boron concentration is between 10 - 100 ppm recorded only from the dull lithotypes. On the basis of organic petrology, the inter-seam sediments, flora and the very low concentration of boron, the depositional environment postulated for the coal is braided, fluvial and fluvio-lacustrine with marked fluctuations in the water table. The low water table in the environment accounts for fusain and inertodetrinite in the coal.

Jan 1, 1996

Single station group velocities of fundamental made Rayleigh waves over the period range 15-100 s are carguted for five provincial profiles of the West Pacific. Based on recordings of earthquakes around the West Pacific by the W~ (World Wide Standard Seismic Network) stations AFI (Afianalu), HNR (Honiara), WEL (Wellington), PAR (Raratonga) and RAB (Rabaul). The inversion of the derived dispersion curves for average shear velocity-depth structure of the crust, LID and LVL shows that (i) the over-all structure beneath the profile 'westernSamoa-Micronesia-Mariana' is in between that of regions 3 and 4 of Pacific Ocean (Yu and Mitchell, 1979), except that the velocity is slightly lower, (ii) the uppermost mantle beneath the 'Vitiaz Trench' profile between AFI and HNR is similar to that of region 2 of the Pacific - in other words, thin LID and thick LVL; (iii) the structure beneath the ' Ibnga-Keradec Ridge' profile has a thick crust with thick sediments, and LID-LVL velocity and thickness are similar to region 3 of the Pacific; (iv) beneath the profiles ' Tonga/ Kermadec Trench events-RAR station' the structure is intermediate between regions 3 and 4 of the Pacific Crean; (v) from decomposition of the 'Solomon-meriana' profile, the structure beneath the Cntong Java Plateau has a thick crust with thick sediments and the uppermost mantle is similar to that of region 3 of the Pacific clean.

Jan 1, 1990

In the future to excavate sufficient coal for power generation, two dredgers would be required to dig overburden or interseam 70010 of the time and three dredgers 40010 of the time. One overburden system was not adequate for this requirement, making coal production reliability vulnerable. TS5 spreader is the new machine element of this system. The selection of the best type of machine configuration to suit the application was then subject to an internal SECV VE Study, a registration of interest and a tender for two machine alternatives. This paper outlines the reasons why SECV planned the Secondary Overburden System and how the Krupp machine met these requirements. It also identifies the main design features of the machine and its constructability which will allow the machine to be operational by the end of May, 1990.

Jan 1, 1989

By Chang TS, Suzuki K, Go H, Nakamura S, Kuwano Y

In 1979, a test operation of an experimental blast furnace was carried out to investigate the behavior of a sort of formed coke, which was used safely by 30% of total coke charge in No.2 B.F., Sakai works, NSC, in 1975". The Mashec-type formed coke of 60 x 60 x 40 mm in dimension was crushed and screened so that it had the same size range (1011,20 mm) as ordinary coke used in the base operation. Preceding to the operation, some experiments on the properties of the formed coke and the effects of crushing on them were performed.

Jan 1, 1981

Martin Mining and Tunnelling Pty Ltd is a mining contractor with offices in Kalgoorlie, WA, Australia and Timmins, Ontario, Canada.Martin Mining and Tunnelling Pty Ltd offers services in mine contracting which include shaft raising, raise enlarging, excavation of rock passes and ventilating systems. It also offers the mining industry a unique mining method using the Alimak raise climber system.The Alimak raise climber system may be utilised in various types of orebodies, as the system is flexible to change. Sloping widths, drill hole patterns and changes in dip can all be accommodated with this method.This system allows for a highly productive, cost-efficient alternative to conventional longholing methods. This paper will focus on various aspects of the Alimak system which inherently make it a safe, viable method of ore extraction.

Jan 1, 1993

By Linying W

Entropy is an important concept both in natural and social sciences.Considering the preparatory process of the earthquakes as an open system, in view of basic ideas of the Theory of the Dissipative Structure, the seis-mological Entropy is introduced as an order parame-ter, describing the scale of order associated with the earthquake distribution in time, space and mag-nitude. The features of evolution of seismic acti-vities before and after the large earthquakes have been studied by using the seismological entropy.The preliminary results show that the seismological entropy in certain region decreases as the large earthquake is approaching, it means that the distri-bution of earthquakes has turned gradually in order from disorder.It is expectation that the application of the Principle of Entropy in seismological research will deepen the understanding of the physical process of earthquake preparation. Meanwhile, it will also offer some enlightements in studying mitigation of seismic hazard as well as earthquake prediction.

Jan 1, 1990

The paper describes the development leading to the bucket wheel excavator systems now used in the Latrobe Valley and refers in particular to the new S.E.C.V. dredgers Nos. 14 and 15 which will be employed in the Loy Yang open cut. The design concept and operating possibilities of these dredgers are described in detail with reference to the machine characteristics designed for the operating conditions in the Latrobe Valley. The design is compared with units of similar capacity in open cuts of other countries.

Jan 1, 1982

This paper will describe the exploration project which led to the discovery of the La Escondida porphyry copper deposit in northern Chile and will serve as companion paper to the description of the geology of Escondida being presented by J M Ojeda. The author would like to express his appreciation to Robert Hickman, Chairman of Minera Escondida, for permission to present this paper.In July 1978, a proposal was made by J D Lowell to Robert Wheaton, then Exploration Manager of Utah International, that Utah fund a "grass roots" program exploring for porphyry copper deposits in northern Chile. Wheaton expressed interest, and it was agreed that Getty Oil Co also be invited to participate. A joint venture agreement for the Atacama Exploration Project was signed January 1, 1979, between Utah, Getty and Lowell. The project was managed by Lowell who reported to a management committee which through most of the project consisted of Lowell, Francisco Ortiz, Robert Wheaton, Maurice Young, Sigfried Muessig and Louis Rove. Oliver Warin and Jim Bratt participated in the committee in the last phase of the contract. Special thanks are due Louis Rove of Getty and Maurice Young of Utah who made contributions throughout the course of the project. Francisco Ortiz was resident manager through most of the project.

Jan 1, 1990

Mathematical economic models for assess ment of technological progress in the mining industry in the USSR are discussed. The models are based on a simple index, TT which approxi- mates the rate of growth of the people's living standards. However, for application in the mining industry it is necessary to incorporate various parameters to account for the dynamic charges in the geological, mining and other technological conditions. Derivations of the models are shown and examples of results are Included.

Jan 1, 1977

By Corbett GJ

Epithermal gold-silver deposits occur in young volcanic terrains where post-mineral cover commonly impedes the search for mineralisation. At the Togi Project in Honshu, Japan, a complex mineralised system is largely covered by post mineral volcaniclastics. A combination of high resolution electrical resistivity surveying and detailed airphoto interpretation has, with close geological control, enabled synthesis of structural and alteration characteristics of the Togi geothermal system, in turn permitting ranking of the prospects for drill testing.

Jan 1, 1990

By Forster G, Datta P. K

Many high temperature industrial processes involve gaseous halogen-bearing environments. Essentially, these fall into three subject areas: power generation, waste incineration and especially extractive metallurgy. Fundamental to any understanding of the process chemistry and efficiency in the process technology is an adequate knowledge of background thermodynamics relating to metal-chlorine reactions. In this context, existing free energy/temperature diagrams for metal chlorides do not include many elements, in particular the so called refractory elements from Group V and Group VI of the Periodic Table, namely niobium, tantalum and vanadium, and molybdenum. This paper reports estimation and calculations of the free energy values for these chlorides. The data is discussed in the context of high temperature chlorination processes.

Jan 1, 1991

By Pinn N

Geosynthetics is an all encompassing word to describe a number of man-made products usually from hydrocarbons which are used in conjunction with the soil. The specific products are:Geotextiles Geomembranes GeonetsGeogrids GeocompositesIn mine establishment and associated construction work, Geosynthetics have proven to be successful in a wide range of applications. For example, geotextiles are now used to assist with the establishment of access roads, site preparation, haul roads and in connection with the construction of embankments for storage ponds and dams as well as for general hydraulic and foundation engineering problems.

Jan 1, 1990

The traditional concept of optimum drill and blast is that it is achieved when ore is produced at the lowest unit cost and, because of the complexities of most mining operations, represents a band which extends either side of an overall cost m

Jan 1, 1998

The middle-Devonian Dulladerry Volcanics is a complex of A-type, predominantly rhyolitic ignimbrites, lavas and breccias. They form a NNW trending belt some 90 km long and 10-20 km wide, east of Parkes, NSW. The volcanics are dominated by widespread ignimbrite units with minor basalts, sediments and rarer andesites. The volcanics were deposited in a sub-aerial, possibly continental rift setting and are similar in chemistry and age to the Eden - Comerong - Yalwal Volcanic Zone (EVZ) on the NSW south coast. The volcanics exhibit an unusual Atype chemistry (high Zr, Y, Nb, REE, Ga). This distinctive composition illustrates that the volcanics are not comagmatic with the adjacent Yeoval Granite Complex or Eugowra Granite, which show typical I-type fractionation trends. Epithermal gold veins occur in basalt and andesite in the Dulladerry Volcanics at Mt Aubrey (Hopf, 1992), near Baldry. Alteration also occurs in the Glen Isla and Red Hill areas, with epithermal sinter recognised at Glen Isla. Copper and minor gold mineralisation occurs at the contact of rhyolite and andesite at Reedy Creek, but is not of epithermal origin. The analogous EVZ also contains several epithermal gold fields and it is this style of mineralisation which provides the most prospective targets in the Dulladerry Volcanics. Although the Dulladerry Volcanics also contain high background levels of REE and metals such as Zn and Pb, the general lack of fractionation and water-undersaturated character of A-type magmas does not lend itself to the development of significant concentrations of these elements into a fluid phase and mineralisation. The prospectivity of A-type volcanics in general could not be regarded as high. However, an indicator of some fractionation in the Dulladerry Volcanics is provided by the fairly low abundance (average 230 ppm) and wide range (

Jan 1, 1995

Evidence abounds for sea-level change having occurred throughout geological and recent time. Driven by climatic changes, by cycles of glaciation and deglaciations, and by tectonics the position of sea-level relative to the crust has been going up and down since oceans first formed. Rates of these differential movements have been as high as 10 mm/year during the last major deglaciation as sea-level rose by about 150 m in about 15000 years. Tectonic processes can also produce change in sea-level relative to the crust of several mm/year as in, for example, the uplift of the Huon Peninsula in Papua New Guinea. To understand what is happening to sea-level today and what may be happening in the future it is necessary to understand the geological and climatic processes that have caused sea-level to change in the past and the best laboratory for the study of these processes is the geological and geomorphological record. Evidence for observations of sea-level change throughout Late Pleistocene and Holocene time is plentiful in the Australian region. Temporal variability is characterized by a low-stand, at more than 100 m below the present level, at about 20 000-18 000 years ago followed by a rapid rise and transgression of the continental margin up to about 6000 years ago. After this time sea-levels remained within a few metres of their present value but the patterns of change are not everywhere the same. The depth of the low stand at about 18 000 years ago does not appear to have been the same everywhere. Nor does the time at which sea-level first reached its present value appear to have been everywhere the same. The fluctuations about present sea-level during the past 6000 years appear to have been different in different localities. As yet there has not been a wholly satisfactory quantitative explanation for this spatial variability. How much, if any, is indicative of vertical tectonics? How much is the result of the Earth's response to the changing surface loads as mass is exchanged between ice sheets and the oceans? Can any of it be attributed to past changes in global climate? Or are the observations just wrong?

Jan 1, 1990

Cerro Matoso (CMSA) in Colombia produces ferro-nickel from lateritic ore containing approximately three per cent nickel, using a Rotary Kiln - Electric Furnace (RKEF) process, in which the calcining of the mineral within the kiln is second in importance only to the smelting of the mineral in the Electrical Furnace. This article discusses the installation and operation of an expert system to control the kiln of CMSA. In the CMSA process, the run-of-mine ore is crushed, homogenised, dried and mixed with a small percentage of coal, before being heated up to 900¦C in a rotary kiln in the presence of natural gas mixed with air in a controlled proportion (air/gas constant ratio). The final objectives of the process are the following: ò To reduce to a minimum the iron and nickel oxides in order to convert these into metallic ions; this is a reduction process to facilitate largely the smelting in the electric furnace. Since the reduction is made with natural gas, it is much more economical than the subsequent complete reduction in the electric furnace, since electrical energy is much more expensive by unit of processed mineral. ò To heat the mineral as much as possible to facilitate the subsequent smelting. ò To eliminate totally the moisture content of the ore. An expert system with fuzzy logic was commissioned in 1994 for the control of the kiln and it has operated with good results ever since.

Jan 1, 1996

Discovered in 1896, the Sons of Gwalia orebody is located in a ductile mylonite zone within a sequence of Archaean pillow metabasalts and minor metasediments of greenschist facies which are variably sheared.The ore zone has good continuity, being 110 m wide and 500 m long, dipping 45 degrees east and plunging 70 degrees to the south to a depth of 1500 m downplunge. A strongly-developed foliation is present together with a prominent lineation paralleling the plunge. The mylonite zone consists of unmineralised chlorite schist and a 'U' shaped mineralised zone of chlorite-sericite schist with varying amounts of quartz-carbonate as veins parallel to foliation, boudins, and locally as massive quartz-carbonate. Pyrite is the dominant sulphide present.Grade control utilises RC holes on a 10 m x 10 m pattern, with infill blast rig holes 5 m deep where necessary.Some visual control of ore boundaries is present and, combined with good ore continuity and a knowledge of the structure of the orebody, enables cost-effective grade control to be achieved. To-date, over three million ounces of gold have been produced from the orebody.

Jan 1, 1993

This paper outlines the thermodynamic and mass balance principles which affect the distribution of cobalt between matte and slag during the pyrometallurgical treatment of nickel-copper sulphides and considers the implications with regard to maximising the recovery of cobalt from the smelting and converting circuit.

Jan 1, 1994

By Haeussler P, Christie A, Bradley D, Skinner D

Mesothermal gold deposits of southern Alaska and Westland, New Zealand have both formed at the seaward edge of major collisional zones in the Pacific basin. In Alaska, production of large fluid volumes correlates in time with the addition of heat into the lower parts of the accreted terranes in the late stages of collisional orogeny. This heat was critical for driving both the metamorphic reactions that released the large volumes of fluid that carried the gold, and the contemporaneous widespread anatexis and magmatism. In Alaska's Chugach terrane, this heat was produced by subduction of a spreading ridge beneath the North America continental margin in the Eocene. The resulting products were the S-type granites and gold-bearing veins. The similar widespread S-type plutonism and gold veining in Westland's Buller terrane suggest that a similar tectonic event could have triggered ore formation along the southeastern edge of Gondwanaland. Based on the Alaskan model, a Devonian or Early Carboniferous age is favoured for high volume metamorphogenic fluid generation and gold vein formation in Westland.

Jan 1, 1995