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By Gregory L. M, Phillips G. N

Although it has long been recognised that there is a diversity of minerals associated with Victorian gold deposits, the degree to which this mineralogy is systematic or haphazard has remained uncertain. Recent work by the authors and students under their supervision permits a sharp delineation of the boundaries between different mineralogical domains, and these are interpreted in terms of recent rapid advances in Victorian tectonics, and the regional framework of Victorian gold geology described in Phillips and Hughes (1996).

Jan 1, 1997

By Laffin N. W

Invariably when a new plant is cammissioned operations personnel on takeover look at ways and means of reducing certain restrictions and improving process conditions. These improvements are generally of a mechanical/engineering nature with minor metallurgical alterations to fine tune and maximise recovery. Most operations are continually reviewing and updating existing equipment and equipment spares to gain the maximum performance hereby reducing operating costs. Design of current carbon-in-pulp/carbon- in-leach (CIP/CIL) plants has evolved to such a high degree that many of the medium sized plants can have a "blue printed" design from one to the next if the same engineering designer is used.

Jan 1, 1989

Introduction.History of Stope Filling at Mount Isa.The Need for a Systematic Fill Programme.Reasons for Filling.Fill Materials and Tonnages.Rough Mullock Fill.Quantities Readily Available.Fill Pass Development.Stope Preparation.Drainage.Hydraulic Sand Fill.Initial Experiments with Mill Tailings.Surface Layout.Operation Procedure.Underground Pipe Lines.Life of Sand Pipes and Cones.Drainage.Old Tailings Dam Sands.Quantity of Fill Placed.Pillar Tonnages.Conclusion and Acknowledgment.INTRODUCTIONFilling practice outlined in this paper refers exclusively to the Black Star section of the mine. The stope filling necessary early in the life of the Black Rock and portions of the Rio Grande sections is not to be confused with the current filling programme.

Jan 1, 1953

By Armstrong M, Kleingeld W. J

Current low prices for many metals mean that deposits have to be mined at high cut-offs (relative to their mean grade), which means that only a small percentage of mining blocks are above cut-off. Worse, at such high cut-offs, the blocks above cut-off are usually not grouped into convenient clumps for mining; they tend to be split into small isolated patches that are difficult to reach and hence expensive to extract. Companies wishing to acquire mineral properties have to be able to work out quickly what percentage of blocks are above cut-off and what can effectively be mined given the mining method envisaged. Moreover they need this information within a relatively short-time. The work presented here relates to typical South African gold mines (ie tabular orebodies) but the long-term objective is to develop tools for quantifying the impact of reserve breakup at high cut-offs for a wide range of underground mines including those that are not tabular. The mining method and the sampling procedure determine whether ore blocks can effectively be located and extracted economically. This project studied the impact of these two factors on the recoverable reserves for Witwatersrand gold mines. In order to be repeatable, the tests were done on numerical models of the deposit obtained by geostatistical simulations. To ensure realism, the orebody model and the mining scenarios were based on a specific mine. The recoverable reserves (ore tonnage above cut-off, the corresponding metal quantity and the average grade) were calculated for a wide range of cut-offs for four mining scenarios, as well as for the base case of free selection: ò Scenario 1: Blocks are taken if their true grade is above cut-off and if they are accessible from a raiseline (no information effect, no marginal blocks). ò Scenario 2: In addition to the accessible pay blocks, adjoining marginal blocks are taken (no information effect, + marginal blocks). ò Scenario 3: Blocks are taken if their estimated grade is above cut-off and if they are accessible from a raiseline. Here the estimator is the average of the face samples (information effect, no marginal blocks): ò Scenario 4: Accessible pay blocks are taken if their estimated grade is above cut-off. Adjoining marginal blocksare also taken (information effect, + marginal blocks). ò Free selection: All blocks whose true grade is above cut-off are taken irrespective of their accessibility. The results can be presented in different ways, for example by plotting ore tonnage above cut-off versus cut-off grade, or metal tonnage above cut-off versus cut-off grade etc. As expected, this shows the hierarchy between the five scenarios from the free selection base case to scenario No 2 (true accumulations, pay +

Jan 1, 1995

By Koppe J. C, Costa J. F C L

This paper compares different results for overburden volume estimation assisted by geoestatistics, particularly using kriging methods. The main goal is to obtain the most reliable digital terrain model for the calculation of the overburden volume. The data was collected on an irregularly spaced grid and interpolated values were calculated to provide a denser, more regular data set before volume estimation. The field work was developed at the Butia-Leste Coal Mine, southern most Brazil, where an accurate survey was done using a total station theodolite with electronic data collector. The study was developed in five main steps: data acquisition, exploratory data analysis, spatial continuity measurements, point and block kriging estimation and verification of the results. Data acquisition was carried out on a 5 x 5 in grid. This dense grid provides an exhaustive data set of the real terrain against which data subsets can be compared for the various interpolation procedures and volume calculation. This provides an interesting insight into the influence of the number of data on the estimation error. Univariate statistics were used to compare each data subset and the exhaustive dataset. Ordinary kriging on the data subsets followed by contouring was carried out using Geoeas and Surfer software respectively. A subroutine written in C provided the link between the files generated in Geoeas and subsequent contouring routines embedded into the Surfer package. Omnidirectional and directional variograms were modelled defining the parameters for kriging estimation using Geoeas. Different variogram models were checked through cross validation prior to kriging. A comparison between the magnitude of the differences in volumes calculated with the different DTMs was attained. These final result indicates the sensitivity of the volume obtained to the number of data points. As the number of data points increases the estimation error decreases, but at some point there is no significant decrease in the final volume with the collection of additional data.

Jan 1, 1995

By N Nosaka

Sinter plants currently have to use many types of ores with different properties due to the great demand for iron ores, which was driven by the massive growth in Chinese iron and steel industry. On the other hand, the development of iron ore mines is limited and the quality of iron ores is in a tendency of deterioration. Therefore, the quick evaluation of iron ores has become more important for a stable sintering operation. In addition to such a background, the CO2 gas emission should be decreased from sinter plants according to the Kyoto Protocol on reduction in greenhouse gases. The present paper first describes the methods for testing the metallurgical properties of iron ores, which use a small volume of sample mainly focusing on magnetite ore that is effective for reducing CO2 and NOx emissions from sinter plants. The sintering properties of ores are evaluated separately according to each stage in sintering process, that is: heating stage before melt formation, primary melt formation in adhering fines layer of pseudo-particles, and assimilation of nucleus ore particle with calcium-ferrite system melts.Next, the application of the tests to the blending ores is introduced showing examples of the studies on the effective usage of the magnetite ores with Marra Mamba type ores.

Jan 1, 2005

By Christie A. B, Swain A, Brathwaite R. L

This study provides quantitative data on vein distributions within seven selected epithermal systems, four deposits hosted predominantly in rhyolitic rocks: Ohui, Wharekirauponga, Neavesville and Komata, and three major deposits mainly hosted in andesite: Martha Hill, Golden Cross and Karangahake. The technique of fractal analysis was used to help quantify vein distribution patterns. The fractal dimensions (D) obtained are related to the number of veins per metre, the degree of vein clustering, and vein thickness. An increase in any of these tends to increase the fractal dimension. It is the relative relationship of these parameters that is important for the characterisation of vein distributions, and the comparison of different deposits. Within the same systems, the rhyolites are characterised by lower vein thickness and vein density, but have a higher degree of vein clustering compared to the andesites. Sections that are deeper and more centrally located within the epithermal system and/or close to major structures, tend to have a greater degree of vein clustering, higher average vein thickness and density, and higher thickness to density ratios. This depth control is most pronounced in epithermal gold-silver systems because they have formed at shallow crustal levels where physico-chemical conditions change drastically both vertically and laterally. In addition to lithological and structural control at vein scale, deposit scale structure is of great importance in the deposition of economic mineralisation. Large open vein structures capable of sustaining high fluxes of hydrothermal fluid, favourable for the formation of large, high-grade gold deposits, are best developed in andesite sequences.

Jan 1, 1995

By Mitchell M. A

The steeply dipping Mammoth orebody is mined by Gunpowder Copper Limited using a sub- level uphole bench stoping method at a mining rate of 350 000 tonnes per year. of three per cent copper ore. Access to the mine, is provided by 1 in 9 decline which spirals in the footwall connect-, ing all the sublevels, thus maximising mobility and accessibility of trackless mining equipment Sublevels are driven in ore off cross- cuts from the decline every 15 metres vertic- ally. Sublevel drives are stripped out to widths up to 18 metres before cutoff slots are mined at each end. A two boom fan drilling jumbo is used to drill inclined rows of holes to the floor of the sublevel above. Two or three rows are fired at a time which allows broken ore and remnants from the level above to be mucked out by rubber tyred LHD equipment to the brow. Ore widths of up to 80 metres are en- countered at lower levels where ring drilling from longitudinal drill drives will break ore to a draw point system below. Development is carried out with three boom rubber tyred jumbos. All haulage from the mine is in 20 and 35 tonne rear dump trucks. All aspects of the mining operation are discussed including ventilation, pumping and drainage, services and future planning.

Jan 1, 1974

By Knight J. L, Baker G

The Wonthaggi coalfield is in South Gippsland, about 90 miles southeast of Melbourne. It is situated on the down-faulted block of the South Gippsland highlands that lies south of the Kongwak fault, between the Powlett River and the sea (Fig. 1). The coal, which is of Jurassic age, occurs in two small, and intensely faulted, limnic basins, that lie on either side of a concealed ridge of Silurian sediments. The coal was first found as thin seams outc1'opping in the cliffs at Cape Paterson, but the seams that are worked at Wonthaggi are concealed beneath a veneer of Cainozoic sands that covers the Jurassic strata, and were found by boring.The c9al seams are worked by the State Coal Mine, which was opened in 1909 to ensure a supply of coal for the Victorian railways, following a prolonged strike in the Newcastle field of New South Wales. The total production from 1910 to June, 1943, amounts to 13,918,800 long tons of coal. The coal seams are faulted to a degree unknown in most coal...

Jan 1, 1944

The Bulli Seam, New South Wales, cenprises middle to high rank bituminous coal, generally of coking quality. It is worked over an area embracing 300 square miles.Variations in several factors are presented:The seam is somewhat. disturbed and 'dissected by various structural features. This structure, and present topography, have resulted in depths of cover from very shallow to approaching 2, 000 ft in the presently, Worked area. Wide variations of seam thickness occur. Gradations of, rank occur from-place to place. Variations in seam gas content and pride variations in seam gas composition are experienced. Variations in coal strength occur. The influences of these factors on the occurrence of stress and gas phenanena in mining exploration are considered.

Jan 1, 1963

The extinction of zinc from steelmaking dusts has been studied with a laboratory scale reduction-vapour deposition (RVD) process in the absolute pressure and temperature ranges of 13 - 1300 Pa and 1333 - 1513 K respectively. This process consists of pre-reduction of iron oxide by carbonaceous agent, carbothermic reduction of zinc oxide under reduced pressure to produce zinc deposits and subsequent re-evaporation of the deposits to liquedify the zinc. In the RVD, the gas mixture of Zn and CO quenched from the hot zone is separated into Zn deposit and CO which is transferred to the pumping system. The Zn are a layer of fine metallic zinc powders accumulated on the cold wall and removed to the vacuum distillation chamber. The experimental works have been carried out according to the following items: carbothennic reduction of zinc oxide under vacuum, carbothermic reduction o zinc ferrite under vacuum, and 3. distillation of the Zn deposits. It has been concluded from these experimental results that the recovery of metallic zinc from the EAF dusts is successful by this process, and a new concept for a practical zinc winning process has been proposed.

Jan 1, 1993

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

A four monthly period was analysed for each retreating longwall face which indicated that output increased from 1140 tonnes/day for Longwall 1, to 1620 tonnes/day for Longwall 2 and to 2090 tonnes/day for Longwall 3. An output of 2500 tonnes/day should be achieved from the new Longwall 4, largely due to the improved tailgate corner design and despite a continuing lump coal problem. The evolutionary trend is a feature of longwall mining; the evolution occurring both with mining and mechanical design at the colliery itself and with the longwall equipment offered by manufacturers. The trend is towards simplicity, increased strength and capacity, simplified maintenance and increase relia- bility.

Jan 1, 1976

By Z Li, D Chalmers, J M. Tenney

This paper presents the findings and analysis of the investigation of effectiveness of thin spray-on liners (TSLs) as a gas management tool in underground coalmines. The project involves spraying TSL on the area surrounding gas drainage holes whereby the TSL acts as a thin membrane decreasing the permeability of the coal. This restricts air migrating through the coal seam and diluting gas from the drainage holes. There are a number of potential benefits from this technique but key points are that gas drainage holes produce gas with higher concentrations of methane. The design and execution of a field trial to investigate the effectiveness of a TSL on purity of in situ methane from gas drainage holes is presented in this report. For eight drainage holes, the results show an average increase in methane purity by 9.14 per cent and a reduction in air contamination by an average 7.93 per cent. Overall methane flow rate decreased by 27.6 L/s; however, flow rates were unreliable due to poor measuring equipment. For most holes, methane purity was not changed significantly; however, certain boreholes were responsible for most of the variation in methane purity. The boreholes showing a dramatic improvement in methane purity were likely those with intersecting cleats covered by the TSL. If the TSL was sprayed over more area, specifically in areas where the cleats are intersecting with holes, it is likely that purity of methane in the drainage holes will increase.CITATION:Tenney, J M, Chalmers, D and Li, Z, 2015. Thin spray-on liners potential in reducing dilution of in situ gas in underground coalmines, in Proceedings The Australian Mine Ventilation Conference, pp 323–328 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By Duncan GR

Having passed through a number of previous phases the best longwall results in Australia have shown a significant increase in the last two years. The results expected from a longwall face can be estimated from the ideal production rate, determined by the capacity of the equipment and the conditions in which it is installed, the utilisation, and the available operating hours. Back analysis of the results achieved suggests that, on average, recent improvements arise from the higher capacity equipment recently installed; the utilisation has in fact reduced slightly. Review of the constraints which limit the longwall results, i.e. shearer speed, AFC capacity, support, advance rate, and man travel speed, shows that little improvement can be expected in the ideal production rate in thinner seams. In thicker seams the AFC often proves the overriding constraint and further increase in equipment size could lead to increased future ideal production rates and is expected. In all cases a concerted effort to increase the utilisation achieved is likely. For deep mines with thin to medium seams this offers the most viable path to improvement; by contrast thick seams with highwall/shallow access may benefit from further increase in equipment size.

Jan 1, 1988

By T N. Little

This paper is concerned with the influence of engineering geology on design of Wall Control Blasts. In the Introduction, the Blast Management Framework and the Blast Design Requirements classification system (previously developed by the author) is drawn upon to set the context. Blasting objective for all wall control blasts involves both profile and damage control. Four classes of approaches for blast design are outlined and briefly discussed. Five distinct wall control blasting techniques are summarised. The general relationship between geology and blast design is explored in the paper. Influence of geology on pre-split and post-split design and blasting direction is highlighted. Wall damage modelling from the closest row of blastholes is also introduced using the Analytical Damage Model (ADM). The relationship of rock properties and explosive selection and in particular the Mach wave generation is introduced to assist blast designer in this regard. Finally a Conceptual Model that relates vibration, damage and rock mass condition has been presented along with some applications that have been undertaken by the developer. Eight conclusions have been formulated based on extensive work in this area and the current study.

Jun 22, 2022

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

Willemite mineralization was discovered in 1966 in the North Flinders Ranges of South Australia, in the course of a stream sediment sampling programme. Further work outlined a total of nine separate willemite occurrences in the Copley/Beltana area, and ten small deposits in the Toondana area south of Parachilna. Mineable reserves of 1 000 000 tonnes grading 36.8% zinc were outlined in three deposits in the Copley/Beltana area and campaign mining of the Main Orebody commenced early in 1974. The main group of deposits all occurred within red, dolomitized Cambrian Ajax Limestone, and most are associated with significant thrust faulting. The area of the Main Orebody group of deposits has been intensely fractured, and the surrounding dolomites are often brecciated and contain up to 5% zinc. Lead and arsenic mineralization are minor components of the main group of deposits. Masses of Middle Proterozoic Willouran Formation crop out adjacent to or close to most of the deposits in the Copley/Beltana area. The Willouran is frequently highly sheared, brecciated, and often contains large inclusions of younger formations. It is believed that most of the Willouran outcrops represent piercement structures.

Jan 1, 1975

A major tool in the search for petroleum is reflection seismic mapping. The period which has seen most of the exploration in Victoria is also one which has seen major advances in this technology, from 1963 try present day. Seismic mapping can be divided into three interlinked areas - acquisition, processing, and interpretation. In acquisition the major changes have been from an explosive energy source in 1963 to gas exploders in 1968 and airguns in 1970. The number of recording channels has increased from 24 to 192, with digital recording introduced in 1966, and floating point recording in 1976.

Jan 1, 1982

By Wylie A. W, Jarrett R. G

Two versions of a radiometric-type caliper for measuring borehole diameter are described. One, based on the bow-spring principle, is suitable for percussion (exploration) drill holes. The other, which utilizes hemispherical wall contactors actuated by springs, is suitable for blast holes. Both utilize low-power radioactive sources and employ a scintillation detector to measure the "inverse-square law" response of the device to changes in borehole radius. The performance of the device is examined and examples of its use are illustrated.

Jan 1, 1976