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This paper is written as a supplement to that of Edwards, Baker and Knight on "The Geology of the Wonthaggi Coalfield" 1, the West Area pit being in an early developmental stage at the time of their paper. The thin seams to the west of Dudley Basin 2 had beenknown for many years but it was not until 1935 that it became necessary to work them. The West Area Pit came into production as Dudley Area Pit approached exhaustion in 1937. From available information it was estimated that early work would be in a 36in. bottom seam. The present top seam was not included in the reserves, but it was to be extracted where it proved thick enough for economical working.THE SEAMSEdwards, Baker and :Knight (1944) had insufficient information to correlate positively the West Area seams with those in the Dudley Basin. Their opinion was, however, that they were a westerly extension of the Bottom Seam. Since then the driving of the present north-east heading towards No. 4 Bench McBride Tunnel has established that the West Area seams are those worked as Bottom Seam in the Dudley Basin. West Area Top Seam is a seam that occurred above the Bottom Seam in the Dudley Basin. Only sporadic attempts have been made to work it in Central Area, because 30in. was considered an economic minimum height until recent times. This seam should not be confused with Top Seam, Dudley Basin, which lies some 300ft. above the bottom seam measures and except in isolated areas over deeper workings has been eroded away in West Area.

Jan 1, 1953

By Falconer A. J

Two magnetic parameters are proposed as a basis for the assessment of ironsands beneficiation. The parameters are deter- mined for raw sand prior to dredging and for magnetic separator head feed over a production period of five months. The relationships between these parameters and the performance of the magnetic separators are examined to establish the value of magnetic assessment compared with the traditional soluble iron assay method. The results illustrate that the first parameter, true magnetic fraction (TMF), has a value superior to that of soluble iron when relating raw sand grade calculated by tri- angulation to magnet performance. In terms of the relationship between magnet head feed grade and magnet performance, TMF and soluble iron perform equally as assessment parameters. For the ironsands mined during the five month period, the second magnetic assessment parameter, composite fraction (CR), is shown to merely reflect TMF and offers no additional information for assess- Ment. Conclusions are that true magnetic fraction has many advantages over soluble iron in terms of time and cost of determination and that it is a meaningful and reliable parameter upon which to base all calculations relating to the mining and beneficiation of ironsands.

Jan 1, 1980

By Baafi EY, Chatterjee PK

The quality of mine planning decisions ultimately depends on reliable estimates of the characteristics of the orebody. The quant- ifiable factors such as grades or thickness can be estimated from field data gathered from outcrops or exploratory drillholes. Since outcrop data is necessarily limited to the periphery of a deposit, extensive drilling generally is required. This paper outlines a method for selecting the number and location of additional exploratory boreholes using an iterative procedure based on a mathematical optimization concept called fixed point theory. The method is illustrated through its application to an exploratory drilling program for a coal mine where optimized locations gave a lower estimate of regional and block variances than a manual Choice.

Jan 1, 1986

By Wallman D

Since 1981 two single entry roadways have been driven at Ellalong Colliery for a total distance of 1 030 metres. They were driven at a height of 1.73 metres within the 3.7 metres thick Greta Seam using a Dosco In-Seam Miner (I.S.M.). Ventilation of the drivage was accomplish- ed by an exhausting fan in series with steel ducting and flexible ducting in the immediate face area. The air quantities provided at the face were more than adequate to comply with the requirements of -the auxiliary fan rules and the Coal Mines Regulation Act, 1912, as amended. The experience gained in these drivages demonstrated that the ventilation of long single entry headings can be practically and safely achieved using existing equipment.

Jan 1, 1983

The orebodies at Kambalda are complexly faulted, folded and intruded. It is realized that the ore reserve calculations will be wrong and steps are taken to minimise the errors. The calculations are a combination of computer data handling and manual input. Initially Geological Ore Reserves are calculated and then production data and experience are used to produce a Planned Mining Reserve. At all stages maximum professional judgement is incorporated. The basis of the calculation is the polygonal method of area estimation, and production reconciliations together with the style of data available indicate that it is a most suitable technique. It is also a tech- nique that is easily communicated to all levels from operators to management.

Jan 1, 1979

By Seymour C. A

Peak Downs Mine, a five million tonnes a year coking coal operation, strip mines a, series of Permian coal seams. Seam thickness ranges from 0.5m to 5.0m, and seams consist of multiple coal plies with intermediate shale and mudstone partings. Four 47m3 draglines strip overburden to a cover depth of up to 60m. Coal loading is by 12m3 shovels and 14m3 to 18m3 front-end loaders. Parting removal takes place where the layer of shale and mudstone between seams exceeds 0.3m in thickness. Parting has been removed by a wide variety of earthmoving equipment in order to evaluate the problem and to select the optimum method from an operational and economic standpoint. Multi-seam stripping of the thicker seams is accomplished by working draglines from spoil- pile benches. Coal seams thinner than lm are recovered by dragline and stacked in the pit for later loading.

Jan 1, 1974

By Johnson N. W, Ralston J, Lauder D. W, Smart St C R

The flotation behaviour of the Hilton ore of Mount Isa Mines has been examined in the presence of two collectors (sodium ethyl xanthate (Ex) and sodium diisobutyldithiophosphinate (3418A)) over a range of flotation Eh values and collector additions. Tests were also conducted in the absence of collector to determine the relative contributions of natural and self-induced floatability of the major minerals in the feed. In these tests the influence of metabisulphite on the self-induced floatability of the minerals was also determined. Attention focussed on optimising the selectivity of galena flotation. It is shown that the Hilton ore sample contained lower levels of naturally hydrophobic iron sulphide minerals than are generally contained in the Mount Isa lead-zinc ore. Furthermore, the self-induced floatability of galena was less than that exhibited by the galena in the Mount Isa lead-zinc ore. Sodium metabisulphite (MBS) reduced the self-induced flotation of galena but had no effect on the natural floatability of the iron sulphide minerals.

Jan 1, 1991

By Wilson R. G

Mining conditions imposed by a coal seam roof can be analysed according to natural causes, before consideration of strata control. All types of roof behaviour can be explained by considering only three independent variables. They are roof rock types, rock stresses and discontinuities. Roof rock types encountered in the Sc.ithern Coalfield of New South Wales (NSW) are sandstone, shale, mudstone, laminite and coal. Each rock has its own mode of failure. Lithological stability of the sediments varies from one type to another. Regional stresses upon a coal seam roof will vary in magnitude according to the proportion of gravitational stress, which is related to depth of cover, and residual stress, which is related to the maximum depth of burial and may be gauged by coal rank. Local stresses will vary according to tectonic deformation, related to irregularities in seam structure.

Jan 1, 1976

The Century zinc-lead-silver deposit has a geological resource of 118 million tonnes averaging 10.2% zinc, 1.5% lead and 36 g/t silver. It lies approximately 250 km NNW of Mt Isa in NW Queensland, Australia, and is hosted by middle Proterozoic age siltstones and shales of the Lawn Hill Formation. Within the orebody, most mineralisation occurs selectively within black shale units as fine grained sphalerite and galena lamellae with minor pyrite and siderite. The black shale units are separated by weakly mineralised sideritic siltstone horizons. The deposit is unmetamorphosed and only weakly deformed, displaying excellent lateral stratigraphic and grade continuity.

Jan 1, 1995

By Maiman R

One method of forecasting prices of metals is based on analysis of historic relationships between prices, inventories and consumption. The first, but generally overlooked step in this analysis should be to remove from the inventory and consumption figures the effects of seasonal variations. The next step is to construct diagrams which show prices plotted against ratios of inventories to consumption. These diagrams indicate that, when inventories are high, prices show little response to changes in inventories. Below a critical level of inventories, however, the psychology of the market changes and small changes in inventories lead to large moves in prices. The critical level of inventories is termed the "pinch-point"; the diagram which shows prices in relation to ratios of inventories and consumption may be called a "pinch-point diagram".

Jan 1, 1990

By Ryan CG, Cousens DR, Griffin WL

The proton microprobe is developing into a vital tool in the geosciences, through its high sensitivity for in-situ detection of trace elements in the ppm regime. This paper will describe the instrument at the CSIRO Heavy Ion Analytical Facility at North Ryde, including features crucial to its successful application in the geoscience. Examples of applications in the basic geoscience and mineral industry related research are described briefly. Conditions required for widescale applications in the minerals industry are Discussed.

Jan 1, 1989

By Black LP, Law SR, Oversby BS, Mackenzie DE, Wyborn D

Three volcanic sequences of different ages occur close together in the Burdekin Falls area, southeast of Charters Towers in northeastern Queensland. The oldest is equated with the Cambro-Ordovician Mt Windsor Volcanics, and consists mostly of strongly deformed, regionally metamorphosed rhyolitic lava and minor feldspathic to quartzose sandstone. This unit is overlain by folded but unmetamorphosed Upper Devonian-Lower Carboniferous volcanics (DCv) of the lowermost Drummond Basin sequence. The primary volcanic facies of (DCv) principally comprises andesitic and rhyolitic lavas, and dacitic ignimbrites. Similar volcanics are widespread in the lowest formations of the Drummond Basin sequence elsewhere, and dominate that sequence east of the Anakie Inlier. The youngest volcanic sequence is Late Carboniferous and composed of lower, more deformed, compositionally diverse ignimbrites, lavas and conglomerates, overlain by generally less deformed rhyolitic ignimbrite sheets. The upper part is equated with the Bulgonunna Volcanics which extend 90km south to the Mt Coolon area. The Burdekin Falls area contains an ignimbrite stratigraphy different from that in the south. However, one of the most voluminous ignimbrites (Locharwood Rhyolite) in the southern stratigraphy is also present in the north, enabling the two to be correlated.Each of the three volcanic sequences reflects proximity to eruptive sources. Both the volcanics at the base of the Drummond Basin sequence and the Late Carboniferous volcanics are largely the products of subaerial eruptions. The former were erupted from several intermediate-composition volcanoes, and the latter from multiple-vent silicic calderas. All three sequences are considered to be prospective for precious and/or base metal mineralisation. Polymetallic massive sulphide deposits occur in the Mt Windsor Volcanics farther west, and many epithermal gold prospects and mines are hosted by the volcanics at the base of the Drummond Basin, especially east of the Anakie Inlier. The Late Carboniferous volcanic sequence is deeply eroded, and co-magmatic high-level plutons are widely exposed; this sequence may therefore be more prospective for deeper-than-epithermal mineral deposits.

Jan 1, 1990

Structural assemblages of veins, shear zones, and wallrock alteration zones arising from fault-valve action on steep reverse fault systems are reviewed using observations from mesothermal gold-quartz lodes in the Archean Yellowknife, Abitibi, and Yilgarn greenstone belts of Canada and Western Australia, the Cretaceous Mother Lode system in the Foothills Metamorphic Belt of the western Sierra Nevada, California and the Victorian goldfield hosted in a folded quartz-turbidite succession of Paleozoic age in Australia. Despite differences in the host rock assemblages, the deposits have many structural characteristics in common. These form a useful exploration guide when re-evaluating comparable, but poorly described gold-quartz vein systems such as those in the Reefton area of New Zealand.

Jan 1, 1992

By Alwan M

At Binebase mineralisation is hosted within an andesitic Neogene volcaniclastic succession on Sangihe Island, Indonesia. Two major alteration types occur; an initial widespread phyllic assemblage of quartz -illite with chlorite, smectite, gypsum and pyrite, and a superimposed quartz - barite - sulphide assemblage. The phyllic alteration arose from a neutral to weakly acidic hydrothermal solution of greater than 200 degrees C, and the quartz - barite - sulphide assemblage arose from a cooler slightly more acidic fluid. This second alteration event is interpreted to have selectively replaced permeable volcaniclastic breccias and coarse lithic tuffs within the altered sequence. Gold and silver mineralisation is associated with the latter alteration, and is locally controlled by the degree of silicification and sulphide abundance. The sulphides present are pyrite, covellite and chalcopyrite. The sulphides are very fine grained with colloform and framboidal textures and were deposited contemporaneously with the bulk silicification of the coarse sediments. A large portion of the mineralised rock has been oxidised to a quartz - barite -limonite - goethite - jarosite assemblage.Coincident gold, silver and antimony geochemical soil anomalies gave the best correlation with anomalous gold and silver grades in bedrock as identified by drilling. Resistivity proved a reliable geophysical method for delineating zones of silicification.

Jan 1, 1990

By Jefferson CW

Middle-to-Late Proterozoic stratigraphy and metallogeny in the eastern part of the Canadian Cordillera and in South Australia are strikingly similar. In both areas, thick, predominantly shallow-water strata and their contained mineral deposits can be divided into three sequences (A, B, C) that record episodic and prolonged continental rifting. It is proposed that Adelaidean strata of Australia were deposited adjacent to Belt-Purcell, Mackenzie Mountains and Windermere strata of the Canadian Cordillera within an epicontinental trough of a "Hudsonia" regacontinent. With the final rifting of this trough, the paleo-Pacific ocean was born. By Early Cambrian time, Australia- Antarctica was on the trailing "east" side of the nascent megacontinent, Gondwana, and was being modified on the "west" by accretion in the Pan-African event. North America, more or less surrounded by trailing edges at this time, was analogous to the Cenozoic African plate. This hypothesis accommodates the available paleomagnetic and radiometric data. It has implications for pre-Pangean plate tectonics, paleogeography, and the predictive metallogeny of both areas.

Jan 1, 1987

The Fosterville goldfield, situated 25 km east of Bendigo, Victoria was at its peak between 1894-1910 with some 47 600 ounces produced (Figure 1). Since that time intermittent mining and tailings retreatment was undertaken until Bendigo Gold Associates delineated a viable resource and commenced an open cut heap leaching operation in early 1991. Unfortunately they encountered financial difficulties and Perseverance Exploration purchased the mine in April 1992. Perseverance operated a successful heap leach operation nearby Nagambie, 100 km east of Fosterville. Based on its acquired heap leaching experience, Perseverance Exploration was able to instigate operational changes to create a successful small gold heap leach operation. The major change was the using of the original multi-use leach pad as a single-use leach pad. The available data allows for a comparison of the two operating systems.

Jan 1, 1994

Alluvial gold exploration is aimed at recognizing areas of anomalous gold content as evidenced by the nature of the drainage system, its age, geomorphic history and other features of the geological environment including the provenances. Subsequent studies to quantify the findings are governed by the need for accurate data based upon precise measurements. Computerization allows the use of more complicated mathematical procedures than are feasible manually, thus promoting the development of more advanced technological aids. Data banks provide the means of storing vast quantities of information for instant recall.Sample representivity is a major problem and a clear understanding of both sampling and analytical requirements is essential for dealing with problems arising from variations in sample size and particle size distribution. Field samples must always be large enough to ensure adequate representivity or the sampling has failed in its purpose.

Jan 1, 1984

Total extraction is a misnomer and invariably some coal losses occur in the mining of pillars. "Fulls" pillar extraction is by the pocket and fender method, the splitting method or the open end method, with extraction in the pillar, and in rows of pillars in planned sequence, using combinations of coal and timber and roof-bolts for support. Where circumstances dictate, partial extraction is used, leaving behind portions of pillars in large blocks for support. The use of such extraction plans and supports as minimum guidelines has contributed greatly to safety in United States Coal Mines.

Jan 1, 1974

By Bratt G. C, Horsham T. R, Langlois D. R

Mercury is precipitated from weakly acidic sulphuric acid plant waste liquor at the Risdon Works of the Electrolytic Zinc Company of Australasia Limited. Factors determining the choice of process and reagent, as well as details of process development including scale- up, and the time scale of implementation are outlined. The plant is designed for a maximum flow of 120 m3/h.of liquor containing mercury and saturated with sulphur dioxide. Mercury is precipitated by fluidised beds of aluminium pellets contained in lead columns. Liquor is then clarified with plate and frame presses. Experimental work on the mercury precip- itation reaction was conducted in three phases involving a scale-up of 100 times in equipment size. Extensive pilot filtration work was carried out on a 1 m2 press. Scale-up of 120 times was required for specification of plant filters. The basis of scale-up is outlined.

Jan 1, 1977

By Nilsson C

Man has always been and will always be part of his environment, in ,a good, bad or indifferent manner. Until quite recently, this environment has been the atmospheric boundary layer above the land masses, and to a limited extent the air-sea interface of the oceans. Since the days when he lived in caves, he has built up a wealth of observations on these two environments,-with ever-increasing scientific precision which unfortunately until quite recently was completely insufficient for modern capabilities of data analysis. Consequently, in a sense, he has left in his wake thousands of years of missed, opportunities for making exact observations and increasing his understanding. The data of the past are lost and he has to be satisfied with what he can assemble from now on when his environ- ment, largely as a result of his actions, is exhibiting more and more rapid variations in time; in other words, time series of observations of phenomena are required, the length of which is critical for most purposes of analysis.

Jan 1, 1970