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A synthetic gold-silver telluride material (mainly sylvanite) has been prepared and its physical and chemical properties checked. Flotation tests using a Hallimond tube were conducted using commercial xanthate collectors. At collector concentrations of 10-3M with the addition of 5 × 10-4 M CUS04, no obvious differences in the mineral recoveries were seen irrespective of whether amyl, secbutyl, isobutyl or isopropyl xanthates were used. However, when the concentration of xanthate was reduced to 10-4 M or in the absence of the copper sulphate activator, the effectiveness of the collectors was in the order: amyl > secbutyl > isobutyl > isopropyl > ethyl. Changes in the slurry pH appeared to have little effect on the recovery of the telluride mineral.Leaching tests of the precious metal telluride showed that both gold and silver dissolve in alkaline oxygenated cyanide solutions but at a much lower dissolution rate than metallic gold or silver. Both leaching tests and electrochemical measurements indicate that the dissolution rate of gold-silver telluride is controlled by the pH and cyanide concentration of the leachant.Roasting the gold-silver telluride materials in air at temperatures between 550 and 750°C resulted in its decomposition into a metallic gold-silver alloy and tellurium dioxide.

Jan 1, 1994

By Seneviratne SP

The excessive displacement of the seam floor in headings (i.e. roadways) called 'floor-heave' is often experienced in the underground mines of the Southern Coalfield of New South Wales. Apart from interfering with the mining operations, the phenomenon could be detrimental to the stability of the pillars left for support leading to an unpredictable increase in the subsidence of the overlying strata. The latter could pose a serious problem, particularly in the design of partial extraction layouts of mining for areas where subsidence is to be controlled. The susceptibility of the floor of different rock materials and thicknesses in a given `panel and pillar' partial extraction geometry was examined by two- dimensional Finite Element Modelling of the displacements, stresses and failure zones around the excavations. The modelling, assuming elastic behaviour of the materials, indicated that the maximum vertical displacements of the floor increased substantially as the Young's Modulus of the material decreased to less than 7GPa and the thickness of the layer increased. The results also discount the possibility of a properly designed panel and pillar geometry in the Southern Coalfield of New South Wales being unable to adequately control surface subsidence through the pillar, or its core independently of the yielded ribs, penetrating the floor.

Jan 1, 1992

By W Uhlmann, U Grnnewald, B Nixdorf

Flooding with surface water is the preferred technique for the abatement of acidification from pyrite oxidation in the lakes of abandoned Lusatian lignite mines. However, water resources of the region are limited and in addition, interruption of water inflow during the summer and the termination of the flooding process after reaching the final water level can lead to a re-acidification of the lakes. The development of three mining lakes with a surface-water flooding history of six to 28 years was analysed û in two lakes on the basis of fortnightly to monthly hydrochemical monitoring data. During summer flooding interruption, the younger lakes showed a decrease in pH from neutral down to pH 4. The degree of the pH decrease depended on the intensity of the groundwater inflow from the overburden dumps and this affected the hypolimnion more than the epilimnion. The third lake was flooded 28 years ago and up to now, interruption of the surface water inflow resulted in re-acidification. These three examples were able to show the benefits and limits of the surface water flooding technique for the abatement of Lusatian mining lake acidification.

Jan 1, 2003

By J A. Sanchidrián

The general ranges of validity of some distribution functions are assessed from their behaviour with 119 sets of fragmentation data from bench blasting obtained by sieving. The emphasis is on determining the lower size/passing limit that the size-scaled Rosin-Rammler, Grady and Swebrec functions, and their bi-component versions, can represent with reasonable precision. By fitting these functions to the data using different weights, the accuracy of the fit varies in the different size/passing zones, so that an overall knowledge of the capacity of the function is obtained across the whole size range, from the coarse zone to the fines. Reasonable ranges of use of bimodal Rosin-Rammler and extended Swebrec (all of them five-parameter, bi-component distributions) are, in terms of percentage passing p, 99 > p > 2 per cent (up to 100 per cent for the extended Swebrec), or 90 > p > 0.5 per cent, in which the expected error of the calculated size is below 15 per cent in the extremes of the range, and less than five per cent in most of the central range; maximum errors (ie errors that will only rarely be exceeded) are typically less than 50 per cent in the central range, and up to about 100 per cent in the extremes. Ranges of use for the Swebrec and the size-scaled Rosin-Rammler (three-parameter distributions), with only slightly larger errors than the bi-components, are 100 > p > 5 per cent or 80 > p > 2 per cent. The classical two-parameter Rosin-Rammler can be used in the range 95 > p > 20 per cent or 90 > p > 10 per cent, with expected and maximum errors less than about 15 per cent and 100 per cent respectively.CITATION:Sanchidrián, J A, 2015. Ranges of validity of some distribution functions for blast-fragmented rock, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 741–748 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

Wollongong* is Australia's largest single centre of mining and metallurgy. Wollongong's total employment in manufacturing of basic metal products (over 26,500 in 1972/1973) was almost 50 per cent higher than that of Newcastle and double that of any other Australian city. Although the great bulk of this employment was in steelmaking, Wollongong's copper industry was also a significant employer. Wollongong's total employment in mining (4,900 in 1971) was second only to that of Newcastle among Australian mining centres. Although the bulk of Wollongong's mining is of coal, there is also considerable mining of blue metal, sand and clay. In all, over 40 per cent of Wollongong's work force is employed in mining and metallurgy. The great bulk of the other

Jan 1, 1976

By P J. Clark, A W. Fisher, R G. Ford

Site characterisation of subsurface contaminant transport is often hampered by a lack of knowledge of site heterogeneity and temporal variations in hydrogeochemistry. The use of a regional-scale data compilation derived from satellite imaging is discussed with respect to directing design of site characterisation to monitor the fate of a Dense Non-Aqueous Phase Liquid (DNAPL) plume in Nevada. Evaluation of the drainage basin contributing to the groundwater flux into the study site was used to re-assess the site conceptual model and re-direct the characterisation effort. The use of highly resolved measurements of subsurface hydrogeochemistry in space and time were employed to identify the predominant biogeochemical processes controlling arsenic transport during discharge of groundwater into a pond at a site in Massachusetts. Direct-push conductivity measurements coupled with vertically-resolved sampling within the pond and adjoining aquifer demonstrated spatial and temporal variations in dissolved arsenic within groundwater and the pond water column and sediment pore water. Spatial variability was observed over the scale of centimetres to metres, and temporal variations were observed over the scales of days (following storm events) to seasons. Microbially-driven redox processes maintained anoxic conditions in groundwater and at the sediment-water interface (iron and sulfate reduction) and exerted both a direct and indirect influence on arsenic solution speciation and partitioning to surface water sediments.

Jan 1, 2004

The Southwest Pacific is a region of active volcanism and geothermal systems. Only in New Zealand have the geothermal systems been exploited for electricity generation and industrial processing. At present, approximately 280 MWe of geothermal electricity is generated in New Zealand. A considerable amount of further exploration work is required before the total geothermal potential of the region can be assessed and before the significance of these resources can be judged against other local energy sources.

Jan 1, 1990

By Clarke DS, Sporli KB

Structure is an important control in the localisation of gold mineralisation in epithermal systems. There has been, however, only limited investigation of the structural elements involved; such a study is currently directed at the gold deposits of the Coromandel Volcanic Zone (CVZ). Here, mineralised veining and brecciation ranges up to tens of metres in thickness. Dips of veins are mostly steep, but not vertical, and there is a significant number of low angle veins.The structural control of epithermal deposits may be considered on four scales. At the mega-tectonic scale, pre-volcanism fault patterns mostly relate to separation of the New Zealand micro-continent from Gondwana. The major structural controls on mineralisation at this scale, however, are associated with the volcanic arc processes responsible for the CVZ. Post-mineralisation faulting are linked to the Hauraki Rift and the Colville Ridge-Havre Trough system. Regional scale faults controlling the distribution of gold deposits are the product of these tectonic events; much of the faulting may relate to rifting and calderas, but further work is required to demonstrate this. Detailed study is also needed on vein systems at the prospect scale to validate models of brittle deformation responsible for such systems. Evidence that a variety of structural mechanisms dominated in different deposits is found at the vein scale, with Coromandel gold deposits being classified according to their different styles of vein-fill texture.

Jan 1, 1990

Filter aids are currently used in many industries to increase filtrate clarity and filtration rates. In other industries filtration could be improved if accept- able filter aids could be obtained cheaply. The present paper describes a simple thermal process for making filter aids from coal, outlines the effects of coal properties and major operating variables, and discusses the properties of satisfactory products. Several possible variations in reactor design have been used experimentally, involving fluidized beds of carbon or inert material, reaction of the particles while entrained in air, and a combination of entrainment and fluidization. The limits imposed on product yields by the composition of the parent coal are considered in relation to a range of Australian coals and one New Zealand coal; and the effects of temperature, residence time, and reactant flow rates have been studied in relation to product yields and characteristics.

Jan 1, 1969

By N van Aarde, B A. Moore, S van der Merwe

Frequently materials handling operations are compromised by transfer chute problems ranging from high wear rates, blockages and ineffective loading of the downstream conveyor. This paper will present the design flow implemented to overcome problems in two case studies utilising discrete element modelling incorporating material characterisation.Material testing is relevant in achieving a valid discrete element method (DEM) simulation model and subsequently a valuable design tool for transfer chute assessment and design. It is well recognised that in the current growth and demand for mineral resources, leading to ever increasing conveyor capacities associated with export terminals and mineral processing facilities that transfer chutes are a key focus point. The successful performance of the transfer chute is also dependent on operating with a ærobust rangeÆ of material flowability and handling characteristics. This requirement is crucial in accommodating mineral ores from developing resources, which are often more friable and stickier than in past decades.This paper will include details of chute installations associated with iron ore and coking coal, from the DEM simulations through to the performance of the installed and commissioned plant.CITATION:Moore, B A, van der Merwe, S and van Aarde, N, 2013. Implementation of advanced transfer chute designs, in Proceedings Iron Ore 2013 , pp 445-450 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Liu Wenyong, Huang Yucheng, Yang Ba

High-water rapid-solidifying material, called æhigh-water materialÆ, is a new material developed by the authors over many years. The material can solidify nine times its volume of water into solid. The material is a fine kind of binder with special properties. The solidifying body of high-water material with water has quite a high early strength. The compressive strength of the material within three days can reach the same strength as conventional Portland in 28 days. One ton of the material can replace three tons of conventional Portland cement as binder. Some important achievements have been made in application of high-water material. In metal mines, based on the material, a new full-tailing cemented backfill technology has been developed. The characteristic of the new technology is that high-water material is used as binder and full tailing or alluvial sand is used as backfill aggregate. Because of the application of the new technology, major technical problems in backfill technology such as classifying of tailing, dewatering, transportation of pulp, low strength of backfill body, environmental contamination and so on, have been solved.

Jan 1, 1998

Study on the Effects and Mechanics of Na2SO3 to Chalcopyrite and Galena

Sep 13, 2010

At Great Boulder Gold Mines Ltd. a number of attempts were made to remove water soluble copper and iron salts from calcined pyritic concentrates but variou~ problems arose and the methods were abandoned.A method of rapid washing has been developed and although some problems still exist a workable process was established which resulted in substantial savings of reagents used for the cyanidation of calcine.INTRODUCTIONIn the Great Boulder flowsheet crude ore is ground in cyanide solution, then thickened, agitated and subjected to two stage filtering. Secondary filter discharge is pulped with flotation circuit water, gassed with sulphur dioxide to precipitate soluble gold and activate pyrite, and after the addition of copper sulphate and xanthate, the pyrite and tellurides are recovered by flotation. Flotation tailings are thickened and pumped to the disposal area and concentrates are calcined in Edwards roasters. Calcine is washed to remove water soluble copper and iron salts and the washings pumped to the flotation section where the copper is used as an activator. The washed calcine is cyanided and returned to the crude ore circuit via the thickeners. Solution for precipitation in the Merrill Crowe is drawn from the crude ore thickeners.Prior to the introduction of calcine washing the calcine contained 7 lb/ton copper of which approximately 60 per cent was water soluble. It also contained approximately 90 lb/tol'l of water soluble iron salts. Both the copper and...

Jan 1, 1964

By Greaves M. C, Amos M. D

A study was made of the instrumentation and technique of atomic absorption spectroscopy developed by Walsh of the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia.The method was evaluated for the determination of silver in lead sulphide concentrate. The precision of the procedure developed is equal to that of the uncorrected fire assay method and the accuracy is greater.Brief mention is made of the use of this technique for the determination of silver and other elements in ores and concentrator products.

Jan 1, 1994

INTRODUCTION ò World coal production, Exporters and Importers òNew Zealand Exports, Markets and Products ò Types of Markets and Price Setting ò Bench Mark Prices and Exchange Rate ò Transport ò International Marketing - Key Factors ò Coal New Zealand , the Challenges

Jan 1, 1996

FINANCE FOR EXPLORATION Two factors have basic importance in relation to the availability of finance: the apparent success of continuing exploration activity and tax concessions. It is not proposed to discuss the effect of existing tax incentives, as these have already been outlined and are generally accepted as being reasonably attractive; certainly not a deterrent to possible investors. However, it is obvious that the greater the tax incentives, the greater the amount of money that will be attracted, and the wider the number of people who can be brought into the pool. If, as is suggested, the chance of discovery is related to expenditure and effort, then the more money attracted, the better the prospects of significant finds. It is probably correct to assume that the largest expenditure in mining will come from, or be induced by, people expert in the field, people who are fully aware of the risks and benefits and perhaps making conservative decisions because of this awareness. Insofar as the general public is concerned, while in the first burst of enthusiasm it will frequently follow any promoter, in the long run it too will become more sophisticated and will strongly support only those promoters and companies of good repute and proven record.

Jan 1, 1971

By A Turichshev

The synthetic rock mass (SRM) approach for modelling jointed and veined rock has been at the forefront of caving geomechanics research for years. A well-constructed and calibrated SRM model can capture the full rock behaviour at a macroscopic scale. Traditionally, SRM technology employed bonded particle models (BPM) due to their ability to model rock’s response to loading without prior specification of behaviour. The SRM modelling process requires the BPM to simulate intact rock and the subsequent introduction of fractures or veins by changing bonding characteristics between the particles. However, bonded particle materials have difficulty reproducing both the compressive and tensile strengths of intact rock. This and other limitations of BPM have been the driving force in exploring the potential of grain-based (2D) and bonded block (3D) models (BBM).This paper reports on recent work exploring the applicability of both BPMs and BBMs in 3D to the modelling of intact rock. The advantages and limitations of both BPMs and BBMs are addressed based on the results of numerical simulations using the PFC3D and 3DEC distinct element codes. The preliminary results suggest that BBMs are better suited for simulating intact rock behaviour than BPMs. Ongoing work aims to better qualify the applicability of BBMs under different conditions. This has significant implications for our understanding of rock mass behaviour in a caving environment.CITATION:Turichshev, A and Hadjigeorgiou, J, 2016. Simulating intact rock behaviour using bonded particle and bonded block models, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 453–460 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

In order to appreciate fully the place of palaeontology within the general framework of the geological sciences, consideration must be given to the time, about 150 years ago, just before the study of fossils was beginning to be applied to geological problems. At theend of the eighteenth century, almost all geologists recognised that fossils were the remains of animals and plants that had lived at the time when the rocks in which they occur were formed. It was also realized that many-some geologists thought all-rocks hadbeen formed under water, but as regards the order of succession in which these rocks had originated, and the relative ages of rocks found in different parts of the world or even of one country, only the haziest and most contradictory ideas existed.Around the turn from the eighteenth to the nineteenth century, a widely taught system of theories was that of the German professor, Abraham Gottlob Werner, who believed that the surface of the earth had once been covered by a universal ocean at whose bottom all rocks had been deposited. As the level of this ocean gradually subsided, older rocks-so Werner taught-are now generally found in the mountains or at great depth below the younger rocks; this was his "Primitive Division" which included granite, gneiss, schists, slates, basalt, porphyry and other igneous and metamorphic rocks, all of which he believed to be of sedimentary origin. Younger rocks, according to Werner, were formed at successively lower levels as the water receded. Next in age he placed a "Transition System" of limestones and greywackes; still younger the so-called "Floetz Division," which included sandstone, limestone, gypsum, salt, coal, but also some basalt, porphyry and other rocks; youngest were the alluvial deposits of recent clays, loams, sands and gravel. Thus, in the Wernerian system the age of a rock was determined on the basis of its petrographic properties and the height of its occurrence relative to sea-level.Here and there these ideas survived well into the nineteenth century. As late as 1825, Charles Darwin listened to lectures by Professor Jamieson, one of the last proponents of Wernerian theories in England. The fact that entirely different kinds of fossils occurredin rocks which were regarded as contemporaneous did not worry the theoreticians.It is, therefore, noteworthy and significant that the value of fossils for the interpretation of geological events was demonstrated to the geologists by an engineer and surveyor, WiIIiam Smith, who, although no professional geologist, has often been called the "Father of English Geology." His professional work, which was mainly concerned with drainage and irrigation projects, took Smith to all parts of England, where he sometimes journeyed as much as 10,000 miles in 11 year. Smith was a keen observer and, unhampered by theoretical speculations, he noted the occurrence of fossils and collected specimens wherever he went. Before long he realized that the same kind of fossils followed each other in successive layers of rocks in much the same way in different parts of England, and soon he was able, by looking at fossils collected by other people, to tell from what...

Jan 1, 1950

By Gray J, Krouse HR, Changkakoti A, Kwak TAP

The Dachang tin field with more than one hundred million tonnes of ore at 1% tin and 3% Zn is one of the largest tin fields in the world. It comprises five carbonate replacement tin deposits, of which the Changpo deposit containing about 80 million tonnes of ore at about 1% tin is the largest deposit. The deposit, hosted by middle Devonian limestone, argillaceous limestone and black shale, is genetically related to the Longxianggei granite.The oxygen, hydrogen and carbon isotope data of minerals, rocks and fluids suggest a magmatic fluid which evolved during the crystallization of the Longxianggei granite. Mass balance calculations show that the depletions observed in 180 and 13C values of calcites from the ore bodies to the country rocks were due to continous isotopic exchange reactions between the magmatic fluid and the marine limestones at different W/R ratios and between 300 and 600¦C.

Jan 1, 1990

By P B. Hills, R J. Walton

Narrow vein tabular orebodies are prone to mining induced seismicity. The Tasmania Mine is a complex example of a seismically active tabular orebody, where the contrasting material properties of the host strata and of the orebody itself, serve to exacerbate the seismic response. Analysis of a continuous record of seismicity over a period of seven years has provided significant insight into the fundamental mechanics of the rock mass. Understanding seismicity to permit safe extraction of the orebody has been enhanced by instrumentation of rock mass behaviour in response to mining and mining induced seismicity. It is the purpose of this paper to explore that understanding in respect to the adoption of an alternative down-hole Avoca stoping method for use in particular circumstances.Intensive instrumentation of the Tasmania Mine over a period of four years has provided insight into the behaviour of the rock mass in response to extraction of the narrow vein orebody it encompasses. A range of instruments have been installed in clusters or single installations in order to measure changing stress conditions and the impact of those changes on the rock mass and the reinforcement system.Instruments are often installed in very close proximity to active production stoping. While it has been possible to observe the impact of the mining and mining induced seismicity at very close quarters, instruments installed in these locations are vulnerable to damage and consequently, the level of instrumentation is high. Instruments are continuously logged, typically on a six hourly basis coinciding with the end of regular blasting times. The response of the instrumentation to changed rock mass conditions is considered against the background of development and production blasting and against the seismic record to assess the viability of downhole Avoca stoping.CITATION:Hills, P B and Walton, R J, 2012. Continued observations of rock mass behaviour in response to stoping at the Tasmania mine, Beaconsfield, Tasmania, in Proceedings Narrow Vein Mining 2012 , pp 169-178 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012