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By B Beamish

"All underground coal mines in Australia are required to develop a Spontaneous CombustionManagement Plan (SCMP). The New South Wales Government has developed a guideline (MDG1006) to assist operations to comply with this requirement. A reference document is alsosupplied with the guideline that describes the type of information that is needed for input to theplan, including identifying possible tests that can be used for propensity assessment. However,there is no clear indication of what program of sampling and testing is suffi cient to provide adefi nitive assessment of spontaneous combustion propensity prior to and during mining. This paper reviews the existing methods available for quantifying spontaneous combustion propensity and discusses the sampling requirements that are needed from exploration to mining. A new, more defi nitive method of spontaneous combustion testing is also presented that benchmarks coal self-heating performance from mine ambient temperature to thermal runaway. Examples of the eff ectiveness of this new test method for identifying and quantifying reactive pyrite in coal as well as quantifying the diff erence between dry and wet season conditions are provided in the paper."

Jun 1, 2012

CONTENTSSummaryIntroductionGeographical and Geological Outline of the RegionGrowth of the Mining IndustryTable 1: Production StatisticsGeneral GeologyRecent Alluvium and River GravelsSambeto SeriesMudstone and Basalt ContactVatukoula SeriesIntrusivesStructureGeologic HistoryLodesTable 2: Principal Lodes and Their OrebodiesMineral Assemblage and ParagenesisOre Shoots and Their ControlEmperor MineLoloma MineDolphin MineExplorationConclusionAcknowledgmentReferencesSUMMARYThe Tavua Goldfield was found in 1932 within a basin, both topographical and structural, near the sea on the north side of Viti Levu, Fiji, and has produced over £13,000,000 (Fijian) worth of gold and silver from the three mines...

Jan 1, 1953

By P Hollings, J Holliday

Porphyry copper, gold and molybdenum deposits form in subduction-related settings in association with calc-alkalic or alkalic magmatism. Hydrothermal alteration assemblages are zoned, with potassic cores and propylitic haloes overlain by extensive domains of clay alteration and silicification (lithocaps). Copper sulfides, gold and molybdenite typically occur in veins or hydrothermal breccias, and less significantly as wall rock replacements. Epithermal deposits may form above or to the side of porphyry systems, and may be juxtaposed into the core of a porphyry deposit if rapid uplift and exhumation occur through the life of the magmatic-hydrothermal system. Volcanichydrothermal breccia pipes (ædiatremesÆ) commonly form late in the life of a porphyry system. They may contain clasts of porphyry-style mineralisation, and can host significant epithermal gold resources. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By G Showers, R Triglavcanin

The complexity of understanding the whole thickening process to achieve real performance improvements cannot be underestimated. The last significant change in feedwell design was more than 15 years ago with the introduction of self-dilution systems û firstly with OutotecÆs Autodil, followed by FLSmidthÆs E-Duc. Now, following many years of extensive in-house research, including close collaboration with AMIRA and the CSIRO, Outotec has launched the next generation Vane Feedwell. The Vane Feedwell has been globally patented and installed at various sites. This paper briefly outlines the feedwellÆs development using CFD modelling and its subsequent performance in a æreal lifeÆ site installation. Plant results of the first commercial Vane Feedwell, in a mineral sands application, are discussed. The Vane Feedwell was retrofitted so comparative data of pre- and post-installation is shown.

Jan 1, 2009

The Drake-Rivertree area lies in the far north east of the New England district of New South Wales. Drake is some 500 miles north of Sydney by road and 36 miles west of Lismore. Rivertree is situated 24 miles north of Drake.The Drake deposits were first worked in 1878 for gold which occurred in a very fine state in ferruginous gossan but at depth copper ore became more significant. The lodes at Rivertree, discovered in 1887, were worked for silver but mixed sulphides became more prominent in deeper levels.Several mines operated at each centre and each locality smelted its own ore.The mines at both centres were operated sporadically for many years though production was not particularly substantial.A number of the larger mining companies have shown a recent interest in this mining field with special emphasis on the Drake locality.GENERAL GEOLOGYThe two mining centres are situated to the north and south respectively of a belt of Permian marine sediments and volcanics similar to, and probably representing an easterly extension of, the rocks of the Emmaville district further west.E. C. Andrews (1907) recognized two stratigraphic units within what he called the Drake Series. The Lower Division consists of rhyolite flows, tuft's, breccias and agglomerates, followed by trachytic and andesitic tuft's containing cladochonns, thanmopora willcinsoni and other Permian forms.

Jan 1, 1962

By Watson DF

Calculation of the amount of metal in an ore deposit or mining block should be approached by multiplication and integration of appropriate numerical manifolds describing the spatial distribution of the relevant variables, viz. grade, specific gravity and also thickness for bivariate data. Construction of a numerical manifold necessarily involves some form of interpolation but detailed characteristics of this are often not specified in various automatic methods, some of which even provide manifolds with discontinuities. A manifold used in calculations should describe in a geologically plausible way the spatial distribution of the variable of interest. Different approaches to the problem are discussed and compared. Particular computational inconsistencies emerge when "accumulation" is used as a variable in calculations of average grade. If an ore deposit is variable in relation to its sampling and especially if selection of mining blocks according to grade cut-off is a necessary operational decision, the biases introduced by accumulation methods can bring about serious problems of over-evaluation. Modern computational techniques make unnecessary the use of accumulations; because of potential inconsistencies it would seem unwise to use them in any ore reserve computation.

Jan 1, 1987

By H Beucher

The uranium grade in roll front deposits is the result of successive processes that can be summarised in two steps. First a sedimentary phase, which gives the deposit support, then an oxidation-reduction phenomenon, which leads to the uranium deposit itself. In order to simulate such a deposit, it is important to mimic these different phases. The final aim of such a study is to localise the uranium itself and to reproduce the internal heterogeneity of the orebody in order to simulate the recovery process. The idea in this paper is not to reproduce a genetic approach but to consider the final image of the deposit. Three approaches are proposed. The first one consists of simulating the facies of the sedimentary deposit. The second approach reproduces the distribution of facies resulting from oxidation phenomenon (reduced or oxidised facies). The third approach consists of simulating the mineralisation at the interface of reduced and oxidised areas using the definition of a new data set determined by the grade values. At the end of each approach, the uranium grade could be simulated facies by facies according to the corresponding distribution characteristics. The plurigaussian method dedicated to random set simulations is well-suited for the facies simulations of deposits resulting from several sedimentary processes whether correlated or not. In this paper, the benefit of this method is demonstrated in an actual case study.

Jan 1, 2006

By R Brake

The Enterprise Mine Project (EMP) is being developed by Mount IsaMines Limited as the future source of copper ore at the Mt Isa miningand processing complex. Environmental engineering is one of the majortechnical challenges facing the project because of the depth of theorebodies, high virgin rock temperatures and hot ambient surfacetemperatures in summer. This paper discusses the engineering principles adopted by EMP to manage the risks associated with working in these adverse thermal conditions.

Jan 1, 1998

By V K. Singh, G Sural

The problem of spontaneous heating/fire is very common in coal mines all over the world. The coal industry faces many problems day by day due to the occurrence of spontaneous heating in the open pit coal mines. Presently, about 70 per cent of total coal production in Indian mines is being carried out by open pit mining. Fire in coal, particularly in open pit mines not only causes irreparable loss of natural wealth but also damages the surface structures and pollutes the environment. It is well known that 75 per cent of the fires occur due to the spontaneous combustion of coal. Spontaneous heating is a very common occurrence in coal mines and is a major factor contributing to mine fire. The liability of coal to spontaneous heating causes many serious problems before, during and after mining. In opencast mines, coal immediately oxidises and catches fire due to the intrinsic characteristics of coal, such as low rank, high moisture, high volatile matter, presence of sulfur in the form of pyrites, low crossing point temperature (CPT) and ignition point temperature (IPT) value and less incubation period. In opencast mines, when the coal benches are left idle for a longer time, heat accumulation takes place in favourable conditions and sometimes leads to fire. The purpose of this paper is to present the different successful case studies regarding the safety management of open pit coal mines from occurrences of spontaneous heating/fire.

Jan 1, 2007

Not so many years ago the reason for an inadequate result from a geophysical survey was insufficient data or poor quality data. In many instances such as gravity, magnetic and radiometric surveys, both these constraints are vanishing or have vanished. High quality sensors, improved data storage, accurate differential GPS and top quality interpretive software now enable the interpreter to understand not just the cause of the anomaly but the host environment in which it resides. Examples of potential field data and also data provided by the more complex electromagnetic systems, from Australia Ghana, West Africa, are used as illustrations.

Jan 1, 1997

A methodology for the fatigue life estimation of load haul dumpers, employed in underground platinum mines, has been developed and applied. This method entails the quantification of operating conditions by means of stress measurements. The measurements are then translated into a fatigue loading factor for a finite element model. The results of this analysis are then used to compare all the critical connections in the structure to detail categories in relevant fatigue codes, and predict a life in operating hours for the vehicle structure. The method was applied on a specific model and the results of this analysis were compared to actual failure occurrences with reasonable accuracy. It is intended that the methodology be embedded into performance specifications and purchasing contracts and that technology transfer to OEMs be achieved. Based on the experience of this project and other similar exercises it is estimated that structural life expectancies may be increased across a typical fleet of trackless mining vehicles (LHDs, drill rigs, utility vehicles, dump trucks) by at least 20 per cent.

Jan 1, 2005

The .subject of this paper is to briefly outline various methods of stockpiling and reclaiming, and the use of different types of bucketwheel re- claimers and stackers in these operations. The paper examines briefly the different types of bucketwheel equipment, their operations and relates them to different stockpile layouts, giving examples of their application in Australia.

Jan 1, 1973

The Nagambie heap leach gold mine commenced production of gold in September, 1989. The mine,120km north of Melbourne in Victoria, Australia, was developed by Perseverance Mining Cor- poration Ltd, a junior Australian mining company, with no other operating mines. Gold production to December 31, 1990 was 47,621 oz. The mine is now producing at the rate of about 45,000 oz per year. As of February 28, 1991, resources at the mine are 5.1 million tonnes measured, at 0.65g/t Au while reserves were 1.65 million tonnes at 0.86g/t Au of proven, heap leach ore, plus 0.37 million tonnes at 0.40g/t Au, of dump leach ore. Metallurgical recoveries expected are 80 per cent for the heap ore and 60 per cent for the dump ore. Perseverance Mining Corporation was listed on the Australian Stock Exchange on April 2, 1987, after a capital raising in March that year. At this time the company's issued capital was 4 million ordinary 25ó shares, 3 million of which were issued to the public to raise $0.75 million.

Jan 1, 1991

Bureau of Medical Inspection, Broken Hill, New South Wales.INTRODUCTIONFor a considerable time it has be3n realised that the pathological changes produced in human lungs by the inhalation of free silica varied, not only according to the amount of silica inhaled, its particle size and the period during which it was inhaled, but also according to other mineral elements which might be admixed with the fine silica dust and inhaled along with it, or inhaled subsequently to the silica containing dust. It was observed that, in many instances, these admixed dusts tended to inhibit the action of the free silica in causing injury to the lungs, as well as the development of certain complications, whilst in other cases it was felt that certain substances could actually accelerate the tissue damage caused by the silica.A fresh impetus to the problem of the prevention of the development of silicosis was given when, in 1937 and 1939, Denny, Robson and Irwin published papers entitled "The Prevention of Silicosis by Metallic Aluminum." Working at the same time at the Saranac La.boratory, and quite independently, and using a colloidal aluminum hydroxide, Gardner arrived at the same conclusions as Denny, Robson and Irwin, namely, that in experimental animals the development of silicotic changes could be prevented if eithertogether with the silica, or subsequent to its inhalation...

Jan 1, 1946

SINCE 1900, five underground fires of consequence have beenrecorded in the Broken Hill mines. These occurred at the Junction(1906), Proprietary (1906 and 1916), Block 14 (1906), and Centralmines (1923). All have been extinguished, but at an enormouscost; e.g., in the eleven months following on the 1923 Central mine fire the sum of £187,123 was expended in fire-fighting operations.To this series may be added others, as the South (1925) and British mine (1918) fires, which were extinguished before serious damage had resulted. All, however, have occurred within a period of 28 years, and in a district where spontaneous combustion, a prolific source of fire in the U.S.A., has been practically nonexistent. Therefore, definite fire risks exist in the underground workings of the Broken Hill mines, and, as a consequence, an active fire prevention policy is a necessity...

Jan 1, 1929

The Fraser Range is composed dominantly of basic pyroxene granulites derived from basalts, many of which appear to have been vesicular and*pillowed. Acidic and basic garnet-bearing granulites are important in the west, and acidic granulites and narrow anortho- site layers are dominant in some regions east of the Fraser Range. An extensive flat-lying olivine gabbro sheet cuts the granulites, and in places has been converted to spinel-bearing meta-gabbros and pyroxene granulites. The granulites of the Fraser Range (Proterozoic) are separated from the gneisses and schists of the Goldfields regions (Archaean) by the Fraser Fault, over which there is a large gravity anomaly (gradient 20 milligals per mile). Some of the problems associated with the concentration of Cu, Ni, etc. liberated from mineral lattices during metamorphism, and other principles of metal concentration in granulite terranes, are discussed. The recognition of vesicular and pillowed zones, even though highly metamorphosed, is of fundamental importance.

Jan 1, 1969

Cores of pre-Tertiary basement from ten oil exploration wells are related petrologically to the "axial", "marginal" and "shelf" facies of the New Zealand Geosyncline.A NW. Nelson-type basement is inferred beneath peninsular Taranaki and the western continental shelf. The terms Taranaki Basin and Wanganui Basin are re-defined and the terms North Wanganui Basin, South Wanganui Basin, Pipiriki High, Taranaki Fault, and Turakina Fault are proposed. Major faults are interpreted as of mainly transcurrent type and appear to form the western part of a splay at the northern end of the Alpine Fault. Evidence for a major Cook Strait Fault is reviewed.

Jan 1, 1967

Coal is of tremendous importance for the Czechoslovak econ- omy. The current annual primary energy demand being about 109 million tons of standard fuel (1 ton of standard fuel - 7,000 coal = 29,308 GJ), coal satisfies almost two thirds of our fuel consumption. If compared with the distribution of resources in the world's fuel and energy pattern, the situation in Czechos- lovakia is significantly different, as shown in Fig. I. One of the causes behind the difference is that the Czechoslo- vak oil and natural gas reserves and, hence, their production are insignificant, so that it is necessary to import them. Brown coal will continue to play an important role as a prin- cipal domestic source of primary energy even in the future. While the share of nuclear power is increasing, brown coal represents strategic reserves in the fuel and energy balance.

Jan 1, 1989

By J J. McNee and, J Crusius, T F. Pedersen

The use of water covers is a globally-applied method for minimising acid rock drainage (ARD) and metal leaching. Although the subaqueous disposal of potentially acid-generating materials has been shown to effectively limit ARD, under certain scenarios, metal remobilisation can occur at circum-neutral pH. The following paper presents data from four case studies in which metal mobility from submerged mine waste resulted in degradation to water quality in the overlying water cover. Subcentimetre resolution profiling of dissolved constituents across the tailings-water interface (dialysis arrays), in conjunction with mineralogical information, were used to elucidate the controls governing metal mobility. The data illustrate four pathways of metal remobilisation, including: the release of zinc via the oxidative remineralisation of metal-rich organics at the tailings-water interface; enhanced remobilisation of arsenic as a result of anthropogenic eutrophication; the release of copper resulting from the pH-driven dissolution of treatment sludges; and the release of radium from uranium mill tailings due to the dissolution of radiobarite [(Ra,Ba)SO4] by sulfate-reducing bacteria. The results highlight the conclusion that the chemical stability of submerged tailings reflects both: the solid-phase characteristics of the tailings material; and the physical, chemical and biological characteristics of the depositional environment. In particular, the data illustrate that rigorous characterisation of both the waste solids and receiving environment must be performed in order to assess their compatibility. The results have relevance to the management of tailings repositories including constructed impoundments, pit lakes and natural lakes.

Jan 1, 2003

By Waghorn EP, Gleeson HB

The Loy Yang Optr, Cut is a brown coal mine bring developed in the Latrobe Valley region located some 160 kin south-east of Melbourne, Victoria. The mine has been designed to supply a mine mouth power station at a rate that will rise to 32 million tonnes per year by the mid 1990's. Continuous mining metnuds are employed using bucket Whtel excav- ators and conveyors. This paper describes the basis of the design of the Loy Yang continuous mining system ano cne experience of four years of initial operation.

Jan 1, 1987