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The GDR has extensive lignite deposits at its disposal, which formed the basis for the development of an independent energy source after 1945 and which will retain their significance well beyond the year 2000 (see fig. 1). In 1946 lignite output was about 110 x 106 t. In 1985 312x 106 t was produced and in 1988 the planned output will be ca. 315 x 106 t. Thus, the domestic produc- tion of lignite covers ca. 75% of the GDR's primary energy requirements. More than 80% of the electrical energy is gener- ated by the use of lignite and about 12% by nuclear energy. In addition to this, about 18 x 106 t/a mineral oil and about 6 x 109, m3/a natural gas are imported, predominantly from the Soviet Union. The lignite deposits of the GDR are of Tertiary origin and are recovered exclusively by opencast mining. There are two large regions (fig. 2): - in the region east of the river Elbe (Cottbus/Senftenberg- "Niederlausitz") and - in the region west of the river Elbe (Halle/Leip- zig/Magdeburg). These deposits differ in geological age and conditions of depo- sition, consequently there are differences in their chemical and physical composition and, thus, in their uses. The younger Mio- cene coals of the main region in the East of the river Elbe belong to the epirogenetic type and have a low content of ash and sul- phur. Among other things, they are suitable for the production of brown coal high-temperature coke (Lauchhammer and Schwarze Pumpe). The older Oligocene coals of the Halle/Leip- zig region are bitumenous in certain areas. Therefore, they form the basis for production in low-temperature carbonizing and chemical plants. In the Halle-Magdeburg region, where the lig- nite is in contact with the underlying Zechstein subdivision, so- called "salt coals" are found.

Jan 1, 1989

Although the effects of sea level changes on ore concentration processes are to some extent obvious with certain deposits, e.g. beach placer deposits, they have been largely overlooked with others such as Mississippi Valley type lead-zinc deposits. It is contended that sea level variations may have more profound effects on a wide range of deposits than has previously been appreciated. These deposits include not only placer'and residual deposits but also stratiform copper deposits, Mississippi Valley type deposits, stratiform manganese deposits and Minette type iron deposits. Sea levels in paralic basins profoundly affect the influx of 'detrital sediment, and this has to be suppressed to allow for the accumulation of thick rich deposits of coal evaporites, phosphate or metalliferous sediment. Emergence can be associated with oxidized waters, erosion, and,solution of soluble rocks. Submergence can reverse the Eh trend and can lead to preservation of ores. Both realms of surficial sedimentary environments and subsurface diagenetic environments can be affected by changes in water pressure, gas pressure (pC02), Eh, pH, and temperature as sea levels fluctuate. Even relatively small sea level changes may have profound effects. For example, there is some evidence to suggest that when the level dropped below 100 metres about 10,000 years ago, the Red Sea became isolated by the sill at Bab el Mandeb in the south, and evaporated away to leave a series of shallow lakes. The Red Sea is 1 to 2 km deep. It was at times such as this that the well-known copper-zinc mineralization developed in the Red Sea trough. Changes in sea level also affect the stability field of gas hydrates which can yield large volumes of gas leading to mass movements on the sea floor (Warnke, 1986).

Jan 1, 1987

Computerisation of mine planning activities, specifically in the areas of geology, design and surveying, has been in progress for a number of years in underground metalliferous mines. The combined capabilities of hardware and software have only recently reached the levels necessary to fully support integrated mine planning computer systems in a graphical three dimensional environment. Despite the apparent capabilities of systems now on the market, many sites retain significant parts of their older paper based systems, and employ a mix of two or more software packages. This paper examines what underground metalliferous sites are doing in this area in Australia, and discusses the factors which are inhibiting full implementation of fully integrated computerised systems. Future directions for further developments in the field are also briefly discussed.

Jan 1, 1995

By Angove JE, Johnson GD

Sulphide concentrates are produced in a wide range of mineral processing operations. In the case of base metals they are further treated by smelting and/or hydrometallurgical techniques. In the case of refractory gold ores, sulphide concentrates containing gold are roasted or oxidised by various hydrometallurgical processes. This paper discusses the development of the Activox(R) Process which can provide an alternative method for treating sulphide concentrates. This process consists of fine or ultra-fine milling, followed by mild pressure oxidation to produce solutions of base metals or to liberate refractory gold. Base metal solutions (eg of nickel and cobalt) can be further processed by solvent extraction and electrowinning, while refractory gold can be recovered by cyanidation. The economics of the Activox(R) Process are often better than alternative oxidation techniques.

Jan 1, 1993

Various aspects of the history of mining at The Zinc Corporation, Limited (ZC) and New Broken Hill Consolidated Limited (NHHC) are examined. There are some discussions about the various methods used to mine the pillars left after the primary mining operations, with an enphasis being placed on the more modern pillar mining methods. Some new pillar mining proposals are presented. INTRODUCTION In the past, pillar reserves at ZC/NBHC have been scheduled for mining by labour intensive and high unit cost mining methods. These methods include both undercut and fill and overhand square set timber stoping. Recent technological advances in large diameter longhole drilling and high charge density explosives have culminated in the mechanised Vertical Crater Retreat (VCR) mining method and this method has been successfully used for the extraction of two pillars at NBHC and more stopes are planned. However the use of VCR methods for mining pillars at ZC/NBHC is restricted to approximately 50 per cent of the total pillar reserves and it appears that high cost methods will be needed to mine the remaining Pillars.

Jan 1, 1983

The A J Parker Cooperative Research Centre for Hydrometallurgy has recently been established by a major grant from the Australian Commonwealth Government. The participating institutions in this centre are the CSIRO Division of Mineral Products, Curtin University of Technology, Murdoch University and the Chemistry Centre (WA). The Australian Mineral Industries Research Association is also a partner. Information is presented about the research activities of the Parker Centre, which are focussed on the solid/solution interface. Three research programs have been established in the areas of leaching, precipitation and surface processes (adsorption). The initial projects within these three programs are described. Details are also given of the Centre's education program which include honours degree training, masters and doctoral degrees by research, a masters degree by course work and workshops. The importance of collaboration with industry to the successful operation of the centre is stressed.

Jan 1, 1992

By R J. Nicholson, J M. F Clout

As part of an overall strategy to make significant new technological advances for the sustainability of the mineral processing and related process industries CSIRO Minerals has developed a new dry separation device. It represents a technology breakthrough and has the potential to radically change the way in which dry particle size classification is achieved in the minerals industry. Conventional dry separation techniques have limited applications and often suffer from low productivity, high operating costs, low separation efficiency, the need for dust control and a lack of flexibility. In the absence of efficient dry techniques, wet processing is often used. The use of wet processing either requires the introduction of water into a separation process, which causes environmental concerns through the need for water supply and tailings dams or the use of æunfriendlyÆ chemicals for dense media separations that have considerable impact on handling and disposal. Wet processing also increases operating costs due to plant instability, materials handling, thickening, filtration and product drying. The new CSIRO technology exploits a combination of natural and applied forces to achieve specific particle motions that produce size separation. In doing so, many of the traditional shortcomings of dry separation have been overcome. The CSIRO Dry Particle Size Separator is ideally suited for dry size separation applications within the size range 1 mm to 30 ¦mfor moderate moisture levels (2 per cent), have low unit throughput, produce a fixed cut size and are therefore impractical where very high unit capacity and low operating costs are required. This paper presents a review of dry separation devices together with details of the new Dry Particle Size Separator and typical results for a number of materials, including iron ore and quarry dust.

Jan 1, 2002

By Randall C

Energy studies have been undertaken at a number of open coal mines in the Hunter valley. A range of energy efficiency benchmarks and targets have been established, which, when applied across coal mines, will assist in leading to a significant improvement in energy efficiency in the coal mining industry in NSW, thereby leading to an improvement in environmental performance. Typically, energy efficiency improvements of 20 per cent and higher appear possible at many mines leading to a commensurate reduction in this controllable operating cost, ie energy. On the basis that annual energy costs and net profit are similar for many mines, a reduction in energy costs by 20 per cent will lead to increase of 20 per cent in net profit.

Jan 1, 1995

During conventional eddy current separation, a repulsive force is applied to metallic particles by placing them in a rapidly changing magnetic field generated by a spinning magnetic rotor carrying an arrangement of alternate magnetic poles. This method works effectively for larger non-ferrous metallic objects, such as aluminium cans, but as the metallic particles become smaller, the bulk repulsive force on the particles is increasingly replaced by a rotational torque. Therefore, for small metallic particles it makes sense to use particle rotation, rather than particle repulsion, to effect a separation. Eddy current separators using particle rotation are similar in construction to present separators, but are designed to produce a rotating field of essentially constant angular velocity and field strength. Practical and economic particle rotation eddy current separations are possible down to particle sizes of about 200 ¦m, but separations, at probably uneconomic rates, can be carried out on particles as small as 50 ¦m.

Jan 1, 2000

By M Simpson, K Brodie, J L. Mauk

Subaqueous water-rock reactions that occur at the pit wall/lake water interface can affect the pH of pit lakes. Many pit lake water chemistry models neglect subaqueous reactions, which may create inaccurate predictions over time. A mineral quantification method is presented that defines the wall rock mineralogy of active open pit mines, using samples collected from the Martha Mine, a low-sulfidation epithermal Au-Ag deposit in Waihi, New Zealand. The mineral quantification method has five components: field observations and sampling, X-ray diffraction analyses, selection of representative samples, geochemical analyses, and mineral accounting. Predicted mineral concentrations closely match observed mineral concentrations visually estimated using petrographic techniques. Results of the method can be incorporated into a geochemical model of long-range pit lake water quality resulting from subaqueous water-rock reactions.

Jan 1, 2003

The geological features of the destructive plate margins of the southwest Pacific favour the formation of porphyry type deposits. The major controlling factor favouring the formation of gold-rich deposits of this type is a dense crust. This results in shallow intrusion of large magma bodies beneath andesite stratovolcanoes. Where the intrusives have near vertical sides, the comparatively low temperature of transfer of volatiles from the solidifying melt favours the partitioning of gold into bubbles of volatiles. They reduce the viscosity and density of the melt, resulting in the upward movement of a mineralised melt. With the drop of pressure with upward movement the bubbles separate into a two phase mixture, triggering freezing of the mineralised melt and the formation of a gold mineralised stockwork.

Jan 1, 1995

By Kabel J. G

While a per onnel location system is primarily used to check that nobody is left in the mine at firing time, it is also useful for contacting people, uch a foremen, shiftbosses and tradesmen, who travel over several mine levels during a shift. The system installed at The Zinc Corporation, Limited, Broken Hill, uses punched coded plastic identity tags, with "In" and "Out" tag readers on each level. When entering a level, the employee inserts his tag in the "In" reader, and when leaving, in the "Out" reader. Each reader is connected to a central computer which shows who is still in the mine and their location.The system has been used on 3 levels by 21 men for a trial period of 4 months. It ha proved reliable in an underground mining environment, and employee acceptance has been good.

Jan 1, 1984

The reduction of titanium tetrachloride to trichloride can be achieved by employing hydrogen and electric arcs. It is possible to produce melts containing up to 50% TiCk in the eutectic mixture of LiCl/KCl by striking a D.C. arc at the surface in the presence of hydrogen and TiCl. vapour. If the electrode IS made to just penetrate the surface of the salt mixture, a hot zone results from the' high resistance contact with both lower chlorides and sintered titanium may be produced. The sintered metal forms just below the melt surface while the trichloride forms at the gaslIiquid junction.The "hotspot cathode" appears to offer a solution to the problem of producing coherent deposits as the spong'e metal can 'be continuously withdrawn in a similar manner to the "calcium process".INTRODUCTIONConsiderable interest has been shown for some years in the possible development of a cheap electrolytic process for the extraction of titanium metal, since a method using simple materials and cheap electric power would materially reduce the cost of production. Even when cheap starting materials are used, however, there exist several general difficulties in the operation of plant which both limit the speed of production and increase the cost of the product. It happens that most of the techniques so far tried produce a powder as cathodic deposit, and when this is the case the following difficulties arise:1. The whole contents of the bath must be treated with solvent in order to extract the 'metal powder which may itself tend to oxidise, and thus become contaminated.2. Fine metal powders, which often contain residual entrained salts, are less easy to consolidate by arcmelting than metal sponge.

Jan 1, 1956

By E Kunz

Decreasing the gas content in the worked seam by degassing before the start of winning has proven its worth in some areas of German hard coal mines. On the one hand, it removes the risk of gas/coal outbursts and on the other hand it reduces the gas inflow into the longwall. The underground experiences of the last 30 years have led to a æhit listÆ of coal seams with respect to their suitability to predegassing. Trials in the DMT laboratory and also results gained in the deposit show that the suitability of a seam for predegassing depends on its rank. In seams with volatile matter of 20 - 30 per cent, high efficiency ratings are achieved as a rule, with lower ratings both in seams with lower and with higher content of volatile matter.If the rock pressure is unusually high, the efficiency rating of the predegassing is lower, even in seams which would normally be suitable for this process. Under unfavourable conditions, for example below or above residual pillars, in-seam boreholes cannot be drilled successfully and the method is not practical. But if the worked seam was already stress relieved, the predegassing has an optimal efficiency. Latest investigations show that the distance between the in-seam boreholes can be extended. But in that case, the time necessary to reach the same reduction of the gas content increases considerably.

Jan 1, 2005

By Rawlings C. D

An assessment is made of the potential for thick seam underground mining of black coal in Australia. A brief summary is given of the geomechanical environment and previous mining history existing in a number of areas of particular interest from the point of view of thick seam mining. A classification of thick seam mining methods is presented with emphasis on the critical geomechanical para- meters influencing the performance of such methods. A summary is made of perceived geomechanical research requirements related to thick seam mining in Australian coalfields.

Jan 1, 1980

The current boom conditions in the Gold Mining Industry, open cut low grade gold mines have become the initial cash flow source for most companies. To achieve the required cash flow the head grade needs to be maintained at the required level. The methods of grade control to achieve .the planned head grade have evolved various systems, one of which is the Ditch Witch Trencher. The application of this machine has revolutionised open cut grade control and Geology and this paper records the various methodologies developed in the Eastern Goldfields of Western Australia.

Jan 1, 1987

The role and policies of the Aboriginal Sacred Sites Protection Authority are described in conjunction with the provisions of the N.T Aboriginal Sacred Sites Act 1978. Comment is made on the application of the legislation and these policies to development proposals in the Northern Territory. A brief review of criticisms by both developers and Land Councils is provided together with responses to these Criticisms.

Jan 1, 1984

By Dobias B

A new separation method based on a combination of coagulation and colum flotation was used to treat fine sphalerite in the range 90 per cent - 15 pm with a relative high superfical gas velocity and a thick froth layer. Minerals studied include sphalerite, calcite, kaolinite and baryte. A new developed sedimentometer was used for sedimentation analysis to characterise hetercoagulation of mixture and coagulation after addition of active ions or reagents. A comparison between use of selective frother and depressant (SHMP) was made to deactivate activated minerals. Selectivity of frother for sphalerite was found in flotation test. The depression function of Flotanol for activated minerals was confirmed in sedimentation alalysis. The use of small quantities of HPAM can improve the flotation of fine sized sphalerite particle and reduce recovery of activated gangue minerals in the neutral or alkaline pulp. A satisfactory separation of fine sphalerite from its gangue was achieved by using alkylpolyglycolether (Flotanol) and copolymer polyacrylamide (HPAM hydrolysed polyacrylamide) as frothing and flocculating agents Respectively.

Jan 1, 1993

It is commonly accepted that govern ments have a role in the financing of mineral development. The reasons for government involve- ment are examined in general and in the light of the current situation in Aust- ralia, particularly having regard to the ownership of resources. A brief introduction is given to the new Australian Government bodies, the Petroleum and Minerals Authority and the Australian Industry Development Cor- poration, designed to fill a new role in mineral development, and to the basic changes brought about by the Australian Government's decision to become involved in the future development of the country's mineral resources. It is generally accepted that governments do have a role in financing mineral development. This acceptance does not seem to be confined to Aust- ralia alone but is more a worldwide phenomenon. Mineral development has traditionally been regarded as the pre- serve of private enterprise and there- fore is presumed-to be profitable, and so it is instructive to ask why there is this special role for governments.

Jan 1, 1974

Mount Isa Mines Limited commissioned the Heavy Medium Plant in August 1982. The first processing stage using Mogensen Sizer 2056 dry screens, experienced unresolvable cloth blinding problems in attempting to separate fine, damp Lead/Zinc ore at 1.7 mm. A large proportion of the fines incorrectly reported to oversize and hence to the wet preparation screens. This wet preparation screen overloading produced multiple operating and maintenance problems. The plant configuration precluded retrofitting any alternative proprietary screen. An internal Mount Isa Mines research and development programme was established to design and build a screen to achieve the required per- formance within the site constraints. The resulting ISA SIZER screen has exceeded metallurgical performance expectations. A `clean sheet' approach to the design also permitted elimination of maintenance difficulties experienced with the Mogensen Sizer. Four `production model' ISA SIZERS were installed in February 1988. The ISA SIZER screen, now fully developed is available commercially and will satisfy many screening plant requirements.

Jan 1, 1988