Search Documents

Firedamp drainage has become an essential part of many mine environmental systems, and new applications are arising. Installations are evolving further to satisfy ever changing basic requirements, standards, and iniilny needs. In this paper, water seal, vacuum based installations are considered, as well as moni- toring, protective and control systems which have been developed for continuous, manless, and trouble free operation. Some factors affecting plant capacity and extractor per- formance are identified and assessed. INTRODUCTION Firedamp drainage applications are incr- easing world wide as mining engineers strive for improved safety and security, and further concentration of coal output. Fewer and fewer mines are able nowadays to satisfy coal prod- uction and firedamp control requirements solely by air dilution or by air dilution and underground firedamp extraction plants. As a result, dependence on surface extraction plants is increasing. This paper deals with som requirements and applications of such installations. I. DEVELOPMENT AND PRACTICE Firedamp drainage has existed for over 250 years following the early work of Carlisle Spedding at Whitehaven (1730). Some fundamentals of current firedamp drainage systems can be recognised in the

Jan 1, 1982

The reasons for and the methods of inte- gration of the gold treatment plant with the existing nickel concentrator are discussed. The integration was accomplished in three stages commencing in May 1980 and attain- ing current throughput in December 1982. The problems encountered and their solution, including the design and construction of a new tailings dam are also discussed.

Jan 1, 1984

By Longworth C. R

Competing requirements for land usage sometimes make the correct all- ocation difficult. The decision can be complicated by many factors such as local resident pressure, previous government decisions, economic pres- sures and the duration or permanency of the competing land usages. This problem often confronts the extractive industries with consequent delays in granting leases and some- times considerable local dissension. A proposal to extend the high grade silica sand quarry of the Wamberal Sand Company Pty. Limited is a microcosm of these competing requirements. The sand quarry is located on the New South Wales central coast. It is an open pit operation on a near beach deposit of silica sand suitable for flint glass manufacture.

Jan 1, 1976

The man in the street (and no doubt most members of the Institute) thinks of wire, if he gives it any thought at all, as a most commonplace commodity. It is an accepted necessity, and like most necessities is taken for granted, unless a shortage in one or other of its multitudinous forms or products causes inconvenience.For many years Australia has ·been a large consumer of wire, particularly for fencing. With the rapid development of secondary industry the demand has increased in both size and character until at the present time much of the wire produced in this country is used as raw material for subsequent manufacturing processes. The call has been of so varied a nature that the Newcastle Wire Mills now turn out a greater variety of wire types than any other single plant in the world.In this paper, the aim is to provide a picture of the manufacturing, properties, and uses of wire. No attempt is made to cover the subject in any detail, as the field is much too broad for anything other than general treatment. Many phases, particularly in regard to manufacturing processes, are, therefore, dealt with cursorily, but it is hoped that the paper will, without delving too deeply into the technical aspects of Wire production, give a general appreciation of:- (a) How steel wire is made. (b) The remarkable physical characteristics obtained by judicious combination of chemical composition, heat treatment, and subsequent cold work. (c) The uses of steel wire.HISTORY.Best known of the early references to wire is that appearing in Exodus, where mention is made of gold wire being used for the sacerdotal robes of Aaron. However, the period in question, about B.O. 1491, is comparatively modern history as far as wire is concerned, for specimens believed to have been made about B.O. 4600 have been found. It is fairly certain that the Egyptians produced iron wire in B.O. 4000. Of particular interest is the

Jan 1, 1947

It is now 32 years since Walsh's classic publication (1) heralded the beginning of atomic absorption spectrophotometry (AA) as we know it today. During this time, AA has developed into the most widely used analytical techniques for the determination of the metallic elements. The years have seen progressive changes in instrumentation so that today it is a highly sophisticated technique. One area of development in AA that is experiencing renewed attention is in the area of electrothermal excitation. In this technique a flame is not used by the analyte solution is atomised by an electrically heated graphite furnace. For a large number of elements the graphite furnace atomic absorption spectrophotometer (GFAA) is considerably more sensitive than flame work. It is common to be able to detect concentrations one hundred times smaller than those possible by flame. Today's geochemists are finding that they can gain valuable information out of very low limits of detection. Electrothermal atomic absorption spectrophotometry (or GFAA) allows for low limits of detection and can be seen to be a valuable aid to geochemical prospecting Analysis.

Jan 1, 1987

By S Mitra, B J. Monaghan, T Honeyands, G Evans, R Chowdhury, D Scimone

Due to the harsh operating conditions, wearing of the inner refractory lining in a Basic Oxygen Steelmaking (BOS) furnace reduces the useful life of the refractories and incurs a significant cost component for relining. In this study, firstly, a combined compressible and incompressible computational fluid dynamics (CFD) model was developed to identify the potential wear prone zones in an industrial scale BOS system during the supersonic oxygen blowing phase by quantifying the wall shear stress distributions. Next, the retained slag splashing process was simulated by introducing an inert gas to residual slag mass to achieve a protective coating on the refractory walls. Effect of both design and operational parameters such as lance head configuration, lance position and the initial slag volume on the slag wall coating performance were quantified and most favourable conditions were determined.

Jun 19, 2024

After a short theoretical comparison of various typical large bell tops with the bell-less top for segregation and other ,ffects on the material flowing through the equipment proper, a comparative analysis between classical and the new burdening in the furnace is given, showing the theoretical effects of distribution and segregation on the horizontal pressure variations, temperature values and gas composition in the stack. Then some typical theoretical charging patterns of the bell-less top for wall and centre temperature adjusting, pressure drop corrections, dissymmetric local action for blow-in and scaffolding are described. Finally the available practical results on furnaces equipped with the bell-less top are compared with the theoretical statements made before and conclusions indicate that the new approach to burdening blast furnaces is a real improvement.

Jan 1, 1975

By J Zhao, C E. Loo

The flame front is a narrow region in the iron ore sintering bed where coke particles combust. The maximum flame front temperature is as high as 1400°C. At high temperatures, the sinter mix components react to form melts, which facilitates material coalescence and the formation of dense sinter particles. It is well-established that flame front speed is an important factor influencing sinter productivity, sinter quality and fuel rate. In this work, the effect of suction, coke addition and mix moisture on flame front speed was studied in a pilot-scale sinter pot and also using the outputs of a recently developed theoretical model, which takes into account most of the significant physicochemical processes in sintering. Airflow through the bed has a large influence on flame front speed. A power law relationship between these two parameters means that increasing sintering airflow rate will lead to increased flame front speed, but the increases become smaller at higher airflow rates. Sinter pot test results showed that increasing coke addition decreased green bed permeability and increased flame front temperature, which resulted in increased flame front resistance and decreased flame front speed. Studies also showed that green bed properties are sensitive to sinter mix moisture level. The changes in green bed properties further influence the flame front speed and temperature.CITATION:Zhao, J and Loo, C E, 2015. Dependence of flame front speed on iron ore sintering conditions, in Proceedings Iron Ore 2015, pp 83–90 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By J A. Meadows, M G. Annandale, G Castelain

Bauxite mining on Cape York Peninsula (CYP) commenced in the early 1960s in the region surrounding the town of Weipa. Rio Tinto Alcan (RTA) operates its bauxite mines on the homelands of 11 Indigenous Traditional Owner groups. The mining activity currently operates under three Aboriginal Agreements including an Indigenous Land Use Agreement – the Western Cape Communities Coexistence Agreement (WCCCA) – which provides RTA with access to the land in return for a range of benefits to the Traditional Owners, including employment, training, royalty payments and future relinquishment of the land (Klimenko and Evans, 2009). Despite reports of some ‘good progress’ in meeting the terms of the WCCCA (Klimenko and Evans, 2009, p 5), many of the region’s Traditional Owners remain dissatisfied. Two key areas of Indigenous community concern are the current premining management practices and the outcomes of post-mining landscape rehabilitation efforts.CITATION:Annandale, M G, Castelain, G and Meadows, J A, 2016. Sustainable mining – indigenous community benefit, in Proceedings Life-of-Mine 2016 Conference, pp 173–175 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

Mining operations in the Obuasi mine of AngloGold Ashanti Limited began in 1897 using mainly gravity concentration and amalgamation to recover the gold from predominantly high-grade quartz ores. The mine is primarily an underground operation, although some surface mining still takes place. Ore is currently processed by two main treatment plants: the Sulfide Treatment Plant (STP) for underground ore and the tailings treatment plant for tailings reclamation operations. STP was commissioned in February 1994 to treat 180 000 t/m of double refractory gold ore and it hosted the then world's largest commercial scale bacterial oxidation plant which uses Gencor's BIOX« technology. Gold is recovered by gravity and flotation, with the regrinding of the sulfide concentrate before bio-oxidation to liberate locked gold in sulfi de minerals. The BIOX« product is leached using the carbon in leach (CIL) process. Gravity gold recovery is a major component of STP operations and its contribution to overall plant recovery is about ten to 13 per cent. Gravity recovery has undergone series of technological upgrading, since the very first circuit which consisted of a Knelson concentrator and a Gemeni shaking table which was incorporated into the milling circuit at the start of the plant. Presently, each of the gravity circuits which consists of Knelson concentrator(s), cyclones and Gekko InLine Reactors (ILR), are located at the Milling and BIOX« circuits. More recently a new gravity recovery facility comprising of four 48 inch Knelson concentrators and cluster of ten inch cyclones have been incorporated at the tail of the flotation circuit. An additional ILR will be commissioned in 2010 to treat the concentrate generated from the new Semi Autogenous Mill #2 (SAG 2) Knelson: concentrator tower under construction. Since the inception of STP, significant gravity recoverable gold has been recovered via Knelson concentrators and the employed circuits have seen a number of modifications and upgrades, motivated by ore mineralogical changes and recovery concerns. The pioneering adoption of the ILR technology in 2001 and 2003 was a critical factor in enhancing the improved recovery benefit of the gravity circuits. Therefore the objective of this paper is to highlight the mine's experience in the gravity recoverable gold process with emphasis on plant modifications and gravity equipment upgrade. Operational challenges and the contribution of gravity gold to overall plant recovery are also discussed.

Aug 1, 2010

By S Girard, L Rowland, V Lawson, Y Shields

Since 1948, ValeÆs Matte Separation Plant has been successfully using magnetic separation and froth flotation to separate the copper sulfide, nickel sulfide and Ni-Cu metallic alloy contained in Bessemer matte for downstream processing. Though some equipment upgrades have been performed over the years, the flow sheet has generally remained unchanged since the early 1970s. The need to improve metallurgical performance led to the trial of a scalping flotation column to produce a final copper concentrate ahead of the cleaner circuit feed to take advantage of a high degree of copper mineral liberation, reduce cleaner-recleaner circulating loads and decrease the associated loss of selectivity. Plant results indicated that 50 per cent of copper contained in the rougher concentrate could be recovered at final grade target. Results indicate that up to a 1.5 per cent increase in copper recovery to copper concentrate was achieved during the scalper trial due to a reduction in the generation of fine chalcocite which has historically been observed to report to flotation tailings due to surface contamination. Deficiencies are currently being addressed and a long-term trial is scheduled to confirm the benefits of copper scalping.CITATION:Girard, S, Rowland, L, Shields, Y and Lawson, V, 2012. Copper scalping at ValeÆs matte separation plant, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 299-308 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By Siwiec A

The laboratory investigations which are necessary to evaluate the mineral processing effectiveness usually include density separation of narrow size fraction of the feed and one of the products. In each size - density fractions the content of valuable mineral has to be determined. These data and yield in each size - density fraction can be specified by a matrix of partition coefficients. They are counterparts of recoveries. These coefficients can be compared with the mean recoveries at each density or size fraction or the total recovery, to determine which density - size fractions are processed in the best or worst way. The basic categories are: vector of metal content l _i 1711, 7t2, òòò, ltM I ò vector of particle size distribution x = I d1, d2, ..., dN I ò matrix of partition coefficients P11, P12, Pi N P _ P21, P22, ..., P2 N PM1 PM2..., PMN These three conceptions allow one to determine all the basic metallurgical parameters of a mineral processing unit. Losses of valuable mineral are connected with: ò mineralogical composition of the ore (types of minerals, their properties, dissemination, crystallochemical affinity, type and properties of gangue minerals), ò applied technology and technical equipment (beneficiation as a stochastic process, processing methods, process control, intergrowth liberation, water quality). Examples of application of the analytical method proposed are given for zinc - lead and coal processing plants.

Jan 1, 1993

Mine planning typically involves designing an operation to uncover coal with the minimum initial costs with reclamation planning and earthworks being done as an "add on" task. The landform is too steep to remain stable, has no drainage and frequently has areas of excessive acidity or alkalinity. Extensive earthworks are required to reduce grades to an acceptable level and create a drainage system. The flexibility available to the mining engineer to alter the post mining landscape clearly depends on the mining methods. Straight dragline stripping provides virtually no flexibility. However most mining operations over the term of current ten year plans have a substantial pre-strip component. It is this pre-strip material which has the potential to reduce the final reshaping earthworks. The reshaping operation itself is subject to some flexibility with various options being available to re-grade and provide drainage. The full utilisation of this flexibility to minimise earthworks cost should be the aim of reclamation design. ACIRL's current thrust in reclamation is aimed at the integration of mine planning and reclamation earthworks. This involves gathering all environment and agricultural criteria and designing the earth works necessary to produce an acceptable final landform. A key component of our work is the use of computer aided design (CADD) for the design of spoil piles, pre-strip dumps and spoil re-shaping. This approach has been applied to a number of mine sites with earthworks operations covering hundreds of hectares and hundreds of millions of cubic metres volume. We are continuing to provide that consultancy service and at the same time are involved in the development of more sophisticated software tools to apply to reclamation design.

Jan 1, 1991

The Barmac autogenous crushing mill is one of the most successful new comminution technologies to become available to the mining and industrial minerals industries in this decade.The Barmac autogenous crushing mill is an innovative Vertical Shaft Impactor which operates in essence like a high intensity dry ore centrifugal pump with the reduction occurring primarily as a result of high velocity rock to rock impact in a fully rock lined crushing chamber. With applications in a wide range of mining and industrial minerals operations the Barmac autogenous crushing mill presents an opportunity to enhance reduction and liberation whilst providing many cost savings and production increases in new and existing plants.This paper briefly describes the operation of the Barmac autogenous crushing mill and reviews its benefits.

Jan 1, 1990

By L Tatnell, R Mackay, A Tolooiyan

The multi-reversal direct shear test (MRDS) method is commonly used to measure the residual shear strength of soils. However, when the standard direct shear (DS) apparatus is used, the MRDS method is prone to two major sources of error: load cap tilting and specimen loss. These two sources of error can cause erratic behaviour in the residual shear strength curve, making it difficult or even impossible to determine the correct residual shear strength value of the specimen being tested. This paper presents the results of new modifications to the standard DS apparatus that prevent load cap tilting and specimen loss. Consolidated drained testing was performed on highly-over consolidated cohesive soil samples from a Latrobe Valley open pit mine, with results obtained from the modified DS apparatus showing a great improvement in the residual shear strength profile compared to those obtained using the standard apparatus. Large numbers of reversals (up to 14) conducted on a single specimen in the modified DS apparatus showed no notable load cap tilting and no specimen loss occurred. The modifications are easily applied to the standard DS apparatus, and analysis and correction of the data are simple.CITATION:Tatnell, L, Tolooiyan, A and Mackay, R, 2014. Measurement of residual shear strength using a modified direct shear apparatus, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 425–434 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

By A Yame, P J. Pollard, E Atase, J Garu, M Tangwari, D R. Hastings, R W. Smillie

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Townsville prospect is situated approximately 4 km north of the Ok Tedi copper-gold mine in Western Province, Papua New Guinea. Drilling in the 1990s delineated a resource of >1 Moz of gold within shallow, skarn breccia-hosted mineralisation associated with quartz-carbonate infill, together with pyrite, chalcopyrite, pyrrhotite, sphalerite, galena, tennantite-tetrahedrite, arsenopyrite, marcasite, and a variety of Au-, Ag- and Bi-telluride minerals. The deepest of these historical holes (TVL034) also intersected copper-gold-silver mineralisation more than 100 m below the gold-rich zone that is associated with calc-silicate skarn breccia. Although copper-gold-silver mineralisation in DDHTVL034 is associated with clinopyroxene-rich skarn, it was also noted that garnet in the skarn breccia became progressively darker in colour with depth, ranging from green at shallow levels to dark red-brown at depth. This indicated that the skarn breccia is zoned, with more proximal garnet skarn at depth possibly indicating an association with porphyry-style copper-gold mineralisation.Based on this skarn zonation model, recent drilling at the Titan prospect, located approximately 500 m south of TVL034, was targeted at potential copper-gold silver mineralisation beneath shallow skarn breccia-hosted gold mineralisation. DDHTVL 081 intersected 46 m at 6.36 g/t Au from 68 m and 80.7 m and 1.67 per cent Cu, 1.27 g/t Au and 20.32 g/t Ag from 184 m. Exploration is now attempting to define the extent of copper-gold-silver mineralisation by defining structural controls on the skarn breccia together with paragenetic and mineral zoning data.CITATION:Smillie, R W, Pollard, P J, Hastings, D R, Yame, A, Tangwari, M, Garu, J and Atase, E, 2015. Exploration of the Townsville Cu-Au-Ag skarn, western province, Papua New Guinea – preliminary observations of paragenesis and zoning, in Proceedings PACRIM 2015 Congress, pp 593–600 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

Last September, when I was asked to prepare this paper, I was told the subject was "mining," a broad subject indeed! Rather than choose one of the many important technical and economic details which characterize mining today, I turned to a subject which fas- cinates me: mining's image. If we are to survive and prosper into the twenty-first century, and if industry and society are to continue enjoying the material benefits which flow from mining, we must address the melancholy fact that the general public at best does not understand mining, and at worst does not believe it is needed or deserves to continue. While my point of view is largely that of an American mining executive, I would hasten to point out that Homestake has participated in Australian mining for over three decades, and our subsidiary, Homestake Gold of Australia Limited, is now a major producer in this "lucky country." Does society need a viable minerals and metals industry? The answer is obviously "yes," so the challenge is to change some minds: not just those of the amorphous "public," but on a focussed basis targeting journalists, educators, TV commentators, politicians and opinion makers of all stripes (I thought of using "rifle shot" instead of focussed but thought that might be misconstrued). Along the way we miners must also look deeply into ourselves, our attitudes towards the society in which we function, and our willing- ness to change as well as to seek change in others. How did we become such bad guys? More than a century ago mining was not just accepted, it was even romanticised. In America, we had altered the time-honored concept of "Crown" lands into public lands made easily available to settlers pushing back the frontier. Miners even preceded the farmers and stockmen in what was perceived as nation-building, although by the 1890s there was a growing interest in conservation, especially the protection and management of forests and national parks. Even though emphasis was shifting toward government stewardship and away from trans- fer of public lands to private ownership, homesteading and mining were clearly recognised as valid uses requiring not just access, but security of tenure. Indeed, conservation as it was then understood implied management of the public domain as well as its protection. Initially this was no great problem to the U.S. mining industry, but as the nation grew and competing land uses became more important, conflicts began to appear, first over water rights and later over air quality and destructive mining practices. But these were local disputes rather than national issues, and two World Wars, the Great Depression and post-war reconstruction lulled our industry into thinking that nothing had really changed. After the storm began to break in the 1960s, the mining industry found itself confronted by a growing maze of complex and costly laws and regulations. It took us longer than it should have to realise that, in facing this challenge, we seemed to have lost the understanding and support of many of our legislators and a majority of the general public. For over 20 years now, since the first Earth Day in 1970, the U.S. Mining

Jan 1, 1991

The McArthur lead-zinc-silver deposit is of the stratiform type. It consists essentially of a mineralized bituminous shale sequence that incorporates tuffites, numerous graded beds, and isolated but massive slump breccia horizons.The principal sulphides are' pyrite, sphalerite, and galena. These occur mostly in the shales. The accompanying turbidites contain only minor mineralization.The geochemistry of the deposit has been investigated in relation to the stratigraphic column and mineralogy of the sediments.A sedimentary origin is proposed for the deposit. Volcanism, thermal spring activity, salinity, regional faulting, and climate are examined as possible factors that may have contributed to sulphide formation and which could be used as criteria for mineral exploration.The metallurgy 'of the McArthur deposit is discussed in terms of its geological history.

Jan 1, 1972

By Sans H

The geostatistical Discrete Gaussian (DG) model is demonstrated to be capable of providing an effective means of implementing change of support for Enterprise-style mineralisation and thus providing reliable global recoverable resource estimates. At Enterprise, sample grade distribution proves to be highly positively skewed, therefore significant deskewing of the histogram and reduction of variance occurs when going from sample to block support. The DG model was experimentally tested in'the Southern Primary Zone (SPZ) at Enterprise, where high anisotropy ratios and pronounced short range structures are observed in variograms. The experimental test was run for a change of support for which the variance reduction was. approximately 60 per cent. This reduction is similar to that predicted by Krige's Relationship ('the volume-variance relationship') for the practical situation of a change of support from 5 m vertical blasthole samples to 3 m x 8 m x 5 m selective mining unit (SMU) blocks. The DG model was found to correctly predict the grade tonnage relationships for a wide range of cut off grades. The experimental test indicated that, given a representative histogram and variogram, the DG change of support provides a computationally efficient and practical means of reliably assessing global mineable resources at the early stages of a mining project. Further, it allows a range of selectivity strategies to be meaningfully and comparatively considered prior to mining.

Jan 1, 1995

By R Dimitrakopoulos, R Senécal

This paper presents a metaheuristic solution to the optimisation of open pit long-term production scheduling with a stockpile and geological uncertainty. The optimisation formulation is a two-stage stochastic integer programming (SIP) model that determines the optimal mining sequence that maximises the total discounted cash flow, while penalising for high deviations from production targets. A parallel implementation of Tabu Search is proposed to accelerate the solution of the SIP formulation and take full advantage of multicore computer processing. Different variants of the proposed algorithm are applied to a case study to assess the performance of the parallel approach. The proposed algorithm and variants are benchmarked using linear relaxation of the complete problem to determine robustness and provide a better overview of the related performance. The results show a net improvement over the sequential solution, and the new proposal seems to be promising when working with a large-scale data set.CITATION:Senécal, R and Dimitrakopoulos, R, 2014. Parallel implementation of a Tabu search procedure for stochastic mine scheduling, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 405–414 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014