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By Chen J, Zhu D

A detailed study on oil agglomeration of fine metal oxide particles is presented in this paper. The major content embraces several aspects which may possibly reflect the current trends in oil agglomeration such as the effect of chemical and physical parameters, the activation of target minerals and the deactivation of gangue particles, the mechanisim of bridging liquid and the kinetics of oil agglomeration process. Systems of ilmenite-feldspar, manganese dioxide - quartz were seperated successfully through oil agglomeration followed by decantation or flotation technique respectively. A triple mixture of vandium-bearing titanomagnetite ilmenite and feldspar was processed satisfactorily using a composite technology: oil agglomeration-decantation-magnetic concentration.

Jan 1, 1993

A modular computer-based monitoring system for mines is dis-cussed. The system consists of the following modules : production moni-toring system HADES, methane monitoring system CMC, seismoacoustic and seismometric systems SAK and SYLOK, communication systems. The system enables one to compose flexible,` economic structures according to the specification of a mine. Application of microcomputer-based monitoring and control systems in coal preparation plants also is discussed.

Jan 1, 1985

By Roberts M. L

Long Shaft was initially developed using a rail haulage system on every working level comprising battery electric locomotives and granby trucks loaded by rail mounted rocker shovels. Production was commenced using conventional hand held cut and fill mining methods. In an effort to improve productivity and reduce operating costs a mechanised cut and fill stoping method evolved to suit the wider sections of the orebody. To further improve productivity and reduce costs the mechanised levels of the mine are progressively being redeveloped to enable the use of trackless diesel haulage equipment. An added benefit of trackless haulage equipment will be the ability to place development mullock into stopes as Fill.

Jan 1, 1988

Drilling and blasting operations have historically been viewed as a necessary 'evil' part of mining, whose costs should be minimised by whatever means possible. In the past, when operations depended primarily on crushing and milling for ore re

Jan 1, 1998

By Gonzalez JM

The Pao gold prospect in N. Luzon, is an example of a high sulphidation epithermal gold system hosted in Mid-Tertiary alkaline volcanics, in the Philippine Arc. Styles of mineralization include: quartz-enargite veins, vuggy silica alteration bodies, and pervasive low grade (0.5ppm) gold mineralization, associated with kaolinite-pyrite-quartz alteration, and geochemically characterized by high As and Hg. Early magnetite-epidote-chlorite alteration linked to an unexposed granitoid is overprinted by an extensive zone of advanced argillic alteration (kaolinite-pyrite-quartz). No alunite is recorded. Important controls of mineralization include; a broad anticline intersected by axial faults, permeable pyroclastic units, and upward confinement of the alteration system by a highly impermeable, clay-rich volcanic unit. At this stratigraphic position the most important mineralization waz developed. The Pao high sulphidation system is not closely related to a stratovolcanic centre, and has formed subsequent to deformation of the volcanic field. It may, however, be related to an unexposed comagmatic intrusion.

Jan 1, 1990

The Myally Beds, Surprise Creek Beds and Mount Isa Group form the upper part of the Proterozoic Western succession of rocks in northwest Queensland. The latter two units are partly equivalent, and are important for their base metal content at Mount Isa and elsewhere. The arenaceous Myally Beds lie unconform- ably or disconformably below the Mount Isa Group and Surprise Creek Beds; they contain four mappable units which were deposited on a broad, shallow shelf washed by east-trending currents. Emergence of the Myally shelf initiated a series of parallel, possibly intra- cratonic, troughs to the east and west. In the east, the Surprise Creek Beds were deposited between the emergent shelf and base- ment rocks, and consist of a shelf and trough facies divisible into 7 and 10 units, respectively. Trough sediments are continuous north-south, and show turbidite character- istics; algal dolomite characterizes the shelf facies. To the west in the Mount Isa trough, an orthoquartzite facies, the Warrina Park Quartzite, defines the base of the Mount Isa Group. Hinge zones between the shelf and trough environments are marked by east-west facies changes, and provide a focus for later major north-south faulting. However, some penecon- temporaneous faulting near Mount Isa is best explained as complex post-depositional faulting of a disconformable sequence. Subsidence and deposition in the Mount Isa trough continued for a longer period than in the Surprise Creek trough, allowing accumulation of lead and zinc deposits in the upper half of the sequence. The Surprise Creek Beds appear equivalent to the lower half of the Mount Isa Group, and are probably not prospective for lead and zinc. Turquoise and possible other secondary copper minerals are widespread in the Warrina Park Quartzite and equivalents in the Surprise Creek Beds, and further investigation of these formations seems warranted.

Jan 1, 1974

By Gemmell J. B

Zinc-bearing massive sulphide deposits have been mined in Tasmania since 1900. The current major producers are Hellyer and Rosebery, with total resource tonnages (mined plus reserves) of 16 Mt (million tonnes) and 24.8 Mt respectively. These deposits belong to the class of seafloor volcanic-hosted massive sulphides (VHMS) and are located within the Mt Read Volcanics, a narrow belt of continental margin calcalkaline volcanics of Cambrian age. Compared to other Australian VHMS deposits, and world-wide MVT and Sedex deposits, the Tasmanian examples clearly stand-out due to their high metal grades, averaging over 17 per cent Pb+Zn. The deposits vary in morphology from mound style (Hellyer) to sheet style (Rosebery) with other combinations including stacked lenses (Que River) and disrupted cross-cutting bodies (Hercules). All deposits show the classic VHMS zonation from an Fe-Cu-bearing base to a Zn-Pb-Ba-rich top. Zinc, gold and silver tenor commonly increases toward the stratigraphic top of the deposits. The ores have been deformed during regional metamorphism, resulting in folding, shearing and recrystallisation of sulphide lenses. In addition to the major deposits, a number of small massive sulphide prospects occur throughout the volcanic belt and the potential for the discovery of further large, deeply buried deposits remains high.

Jan 1, 1993

By Reid T. W

This paper describes the results of investigations into the relationship between specific gravity and chemical composition in the Cockatoo Island orebody, In the early investigations the samples were classified into groups according to porosity. This resulted in high, medium and low porosity groups, the latter being further subdivided into ore and waste. Whole number tonnage factors were assigned to each group. In the later investigations the reciprocals of bulk specific gravity and true specific gravity were ex- pressed as linear combinations of iron, silica and alumina using stepwise regression. The efficiency of the models as predictors was tested by dividing the data into two sets; one of which was used to calculate the regression equation and the other to test the efficiency of the equation as

Jan 1, 1976

Some mqre facts and inferences are presented in amplification of a recent paper on the geology of the Kalgoorlie Golden Mile stressing the volcanic origin of its rich gold ores, some of which are considered tobe exhalites. Previously unpublished and largely unmapped pyroclastic features in carbonated and chloritized, but not in amphibolitic, country rock are brought to attention. This applies particularly to the main host, viz. the relatively coarse-grained quartz dolerite greenstone (Q. D. G.), i.e. Golden Mile Dolerite, and gives more credibility to the spatial association of the rich Green Leader and telluride ores with bodies of sediments and tuffites occurring within, or adjacent to, Q. D. G. There may be an intrusive relationship with contiguous mafic amphibolites of doleritic origin, but this is not certain and can only be resolved by morecomprehensive mapping than in the past. Volcanic features have always been recognized in CalC Schist, i.e. Paringa Basalt, more so recently in the shape of coarse volcanic breccia.Iu the subsequent deformation of the gold ores since their inital emplacement there appears to be a structural parallel with some Canadian base-metal deposits, most of them of volcanogenic origin.

Jan 1, 1976

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

Progress on this project will be verbally reported and a description given of the main features. A detailed feasibility study was completed in December 1986, and the Joint Venture has issued an Environmental Impact Statement. This was open for public comment until 16 February. Issues presently being considered include economic justification traffic, air quality, noise, marine fauna and flora, visual impact, heritage and construction impact. Detail design and construction is likely to commence in mid 1987, following determination of the above matters.

Jan 1, 1987

On Wednesday 11th November, 1970, a series of violent explosions occur-- red within No.1 Basic Oxygen Steelmak- ing (B.O.S.) furnace at the Whyalla Works of the Broken Hill Proprietary Co. Ltd., (B.H.P.) when the furnace was moved immediately prior to tapping. Water from a burnt out flux chute had flooded the bath while the furnace was tilted slightly towards the tapping side waiting to tap. Although no one was injured, dam- age in excess of $54 000 was caused to the hood and superstructure. The water hydrated the burnt dolomite refractory lining some of which sub- sequently collapsed exposing bare fur- nace shell over part of the cone.

Jan 1, 1975

By Dunne R, Defilippi J

Dump leaching began at Teller in late-1988 at a rate of 4 MTPA and has been progressively expanded to the present rate of 10 MTPA. Teller's on-going commitment to dump leaching is driven by the amenability of gold ores to the process and the availability of large tonnages of low grade gold ore. The sequence of evaluating ores for dump leaching involves rolling bottle tests on coarsely ground ore, followed by small and large column leaching and finally trial heaps. Trial heap tests are very expensive and an alternative approach to this is large diameter column leaching.A four-column permanent facility was built at Teller to specifically evaluate the leaching characteristics of new dump leach ores. Details of construction, operation and dismantling are discussed in the paper. Capital cost for the four column facility was some $45 940, while operating costs are about $24 800 per column.

Jan 1, 1992

At the Nikkel og Olivin nickel mine near Narvik, Norway, Outokumpu has been the operator since 1993. The mine was opened in 1989 and in 1992 Outokumpu commenced operations to secure concentrate deliveries to Harjavalta's nickel smelter in Finland. Annual production is about 740 000 tonnes of nickel ore grading 0.5 per cent Ni, about 25 000 tonnes of nickel concentrate and about 2800 tonnes of nickel metal. All production comes from underground operations which makes Nikkel og Olivin AS perhaps the lowest grade underground nickel mine in the world today. Production is currently from one of two orebodies, which is known as the Western orebody. The Eastern orebody was worked out by 1995. During Outokumpu's operational period the Western orebody has been delineated and taken to production. The underground exploration and definition drilling involved about 15 000 in of diamond drilling, which was carried out during a nine-month period. Following this a feasibility study was undertaken and production commenced. Improvements were made to the mining methods. Previously the mine utilised open pit equipment underground and this resulted in an enormous amount of additional tunnelling. Grade control and ore delineation were previously based on sparse diamond drilling and all geological information was processed manually. The improvements included the use of underground sludge drilling to increase the amount of geological information, the of a new computer system for grade control and mine planning, new automated underground longhole drilling equipment and the of underground mining equipment which reduced the size of the drives. These changes produced a marked increase in the efficiency of the underground Mine.

Jan 1, 1996

The development of the SECV brown coal open cut at Loy Yang will require depressurisation of aquifers both within and below the coal seam sequence in order to maintain open cut stability. Prediction of future open cut dewatering requirements at Loy Yang Open Cut and evaluation of the regional consequences of dewatering has required development of a detailed hydrogeological model of the Loy Yang area. The complex stratigraphy of the coal seam and aquifer/aquitard sequences at Loy Yang have been analysed and integrated with the hydrogeological concepts developed from regional groundwater studies to formulate a realistic hydrogeological model as a basis for finite-element flow modelling.

Jan 1, 1988

By A Geldenhuis, M Hagger, J Maree

Disposal of mine water is a worldwide problem occurring in the coal and gold as well in the metal ore mining areas. Since southern Africa is a (semi) arid region, mining effluents should be treated to qualities such that they can be used for agricultural purposes or that they can be discharged in river system. Studies have shown that partly treated acid mine water can be used for irrigation. A copper mine in Botswana plans to use 5 M/d of treated mine effluent for the irrigation of agricultural product. The results of this study showed that when applying the biological sulfate removal technology the produced sulfide precipitated the metals in the mine effluent, such as nickel, Zn and Mn, to metal sulfide (MeS).

Jan 1, 2003

Heavy media separation serves to upgrade mill feed and reduce unit operating costs, allowing ores to be mined which could other wise be uneconomic. At the Aberfoyle mine at Rossarden in north-east Tasmania, a simple heavy media operation using a converted Akins screw classifier as a separating vessel, removes barren quartz from mineralised material. At the Cleveland mine at Luina on the west coast of Tasmania a more complex ore mix requires a versatile operation combining hydro-dynamic and static separation equipment to provide an efficient beneficiation circuit. The two operations are briefly described with a background of basic heavy media separ- ation practice.

Jan 1, 1978

Simple quotation of quantities of coal reserves neglects the relationship between qualities of coals and their efficient use. If exploitation of a deposit is contemplated, its life expectancy can be deduced only if its reserves are estimated according to the coal user's technological standards. A wide range in properties will satisfy a steaming coal, whereas a high vitrinite high rank coal would be preferred for coking and a low inertinite low rank coal for conversion. In competitive trading the buyer's commercial specification may require weighing against the producer's practical ideals, especially when beneficiation is critical. Differentiation of grades in quality of a deposit provides an intelligent understanding of the economic importance of the deposit. The Wongawilli seam of the New South Wales Southern Coalfield exemplifies the effect of quality criteria upon the extent of in situ, recoverable and marketable classes of economic reserves. Effective management of a deposit will result from simultaneous quotation of coal qualities and quantities in a statement of its reserves.

Jan 1, 1979

By G Johnson, G W. Wilson

The settlement and drainage behaviour of co-mix, or mixtures of waste rock and tailings, are examined in a column study. Three co-mix profiles were observed for settlement, drainage, and pore water pressure response. A fourth profile with waste rock and no tailings was also observed for settlement. Co-mix consolidated faster than predictions for tailings alone, and maintained a saturated void space relative to waste rock alone. Practical benefits of co-mix as a waste disposal technology may include faster time to consolidation than tailings, a reduction in total settlement of placed material compared to tailings alone, and a reduction in acid drainage by limiting the flow of water and oxygen through maintenance of a saturated void space.

Jan 1, 2003

By Szpindler G

The results of pot-furnace tests with 35 bituminous coals from 20 seams in New South Wales and Queensland were used to establish the relationship between coal properties, as determined by standard laboratory tests, and the combustion process. The rate of combustion is influenced chiefly by the expansion of the fuel bed, but this cannot be accurately predicted from the crucible swelling number of the coal.The effects of various other factors, such as calorific value and ash yield, were investigated and statistical analysis of the results shows that the coals could be classified satisfactorily according to two experimentally derived parameters, namely heat-release rate at an air flow rate of 260 lb/sq.ft/hr and air flow rate giving stoichiometric combustion. The grouping obtained is shown to be related to ash yield and swelling number.INTRODUCTIQNThe rate of heat release from the fuel bed of a travelling grate stoker and the efficiency with which the heat is used depend upon the design and method of operation of the furnace as well as upon the properties of the fuel. It is difficult to draw general conclusions concerning the influence of fuel properties from tests on a single stoker installation. In the pot-furnace test, on the other hand, a part of the same combustion process as occurs on a travelling grate is carried out in isolation, uninfluenced by furnace design variables, and consequently the effects of coal properties and of the method of pretreatment can readily be demonstrated.While the combustion pot provides a rapid method of assessing the combustion characteristics of a fuel during the ignition and burn-out stages under standard conditions, and of predicting changes in performance with changes in fuel or in air flow rate, it is unable to simulate certain features of furnace design and operation. Data from combustion pot...

Jan 1, 1962