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By H Zahiri

Utilisation of the InSAR technique for monitoring of subsidence in mining areas, employing open pit and underground mining methods, has large potential due to sensitivity and safety issues associated with usage of the classical surveying techniques. InSAR can also be very competitive concerning the cost of provided results. However, there are a few issues that may significantly limit InSAR applicability for subsidence monitoring in mining areas. The altered terrain topography, involving steep slopes and deep pits, may lead to the layover of radar signal for specific satellite and pit geometry. Also, the highly dynamic character of subsidence induced by mining, especially using mass mining methods, may lead to issues such as apparent heave and ambiguous results. In this paper the authors analyse the above-mentioned issues and demonstrate how InSAR technology was applied, as a supporting system, to monitor large scale and highly dynamic subsidence for a real case study in Western Australia.

Jan 1, 2008

By Brett D

Tailings disposal and water management are one of the most important environmental issues in mining projects. The nature and the method of disposal of the tailings will determine the long term environmental impacts and must be carefully considered at the planning stage so that final abandonment can be economically achieved. If not, long term and on-going treatment and amelioration may be required to achieve environmental standards. Final abandonment requires dam safety surveillance inspection to satisfy engineering stability and hazard requirements as well as environmental issues. Environmental issues include stability, as well as rehabilitation and long term contamination potential.

Jan 1, 1991

By McManus D

Situations where in-pit bench stripping methods are favourable are introduced. Examples from Peak Downs Mine are used as a guide to the range of methods available.A number of geological and geotechnical conditions adverse to successful in-pit bench stripping are described. In all cases bench, floor, and/or final lowwall instability can develop and compromise the economics of extraction.

Jan 1, 1992

By Eddy B. W, Washusen J. A, Wulff R. T

The State Electricity Commission of Victoria (SECV) has been con- tinuously involved in the extraction of brown coal from open cut mines in Victoria's Latrobe Valley for over 60 years, but have not completed a major mine. Detailed consideration for rehabilitation at this stage has only been able to be given to overburden disposal areas. Increasing interest in rehabilitation in the 1980's led the SECV to review its existing policies and practices and to embark in 1985 on a public consultation process to establish an agreed and accepted policy. This was extended in 1986 to the consultation process for the rehabilitation planning for the Mor- well Open Cut External Overburden Dump. This paper covers the con- sultative process developed and the lessons learned by the participants.

Jan 1, 1989

By Wright S

Single pellets of mixed lead-zinc concentrate containing up to 20 % lead were roasted in the temperature range of 800-1100¦C. Variables studied included pellet size (from 9-8 to 3-2 mm diameter), gas flowrate past the pellet (from 0.05 to 5 ms t), composition of the atmosphere and the effect of additives such as zinc oxide and silica. After defined periods of time, the pellets were removed from the furnace, quenched and submitted for chemical, XRD, SEM and microprobe analysis. The oxidation of the zinc sulphide followed a shrinking core model. Temperature measurements showed that very high pellet temperatures were experienced at the start of an experiment but after 5-10 minutes these approached a constant temperature. The lead loss from the pellets was then constant with time. Thermodynamics predicted the presence of two bands of lead material in the reacted layer of the pellet. These were found in practice. The lead loss from the pellet occurred from the outer oxysulphate layer via the vaporization of lead oxide polymers. The vapour pressure of PbO, and the loss of lead, was dependent on temperature and bulk gas concentrations of SO2 and 02. At 1100¦C the addition of silica greatly reduced the loss of lead from the pellet. Physical factors such as pellet diameter and gas flowrate past the pellet affected the particle dynamics. These results were found to vary in accordance with the predictions of the Froessling equation.

Jan 1, 1989

By Johnstone RD, Rattenbury MS

RACE Quartz-calcite veins containing Au, As, W, Cu, Pb, Zn and Fe cross-cut Alpine Fault- related structures in the Alpine Schist of South Island, New Zealand. These veins, and some other related veins have been deposited by metamorphic fluids at 250¦C to >320¦C at pressures of a few hundred bars. The fluids were very variable in composition, with 0 to 50 mole % CO2 and 2 to 18 wt. % NaCl equivalent. Penetration of hot metamorphic fluids to shallow levels in the crust was facilitated by rapid uplift of hot rocks at a compressive plate margin. Fluid immiscibility at shallow levels caused concentration of salts and metals into the aqueous phase. Gold precipitation was caused by reduction by pelitic country rock and/nr dluILion by other aqueous fluids.

Jan 1, 1987

The combustion characteristics of Australian coals which contain high inertinite have been studied in a laboratory drop tube furnace and a Thermogravimetric Analyser. The pyrolysis chars and combustion residues were microscopically characterised using a modified coal petrography technique. Results indicated that the overall burnout of inertinite-rich Australian coals under pulverised fuel combustion conditions could be generally within a range of 97 - 99 per cent burnout. The studies showed that poor coal burnout cannot be generally related to high inertinite content in the Australian coals. The extent of coal burnout varies from coal to coal and vitrinite as well as inertinite may contribute to the unbumt chars in combustion residues. Combustion conditions had greater influence over char formation and coal burnout than the coal properties. However, under similar pf combustion conditions, coal rank and coal maceral composition had a strong influence over the coal combustion behaviours and final coal burnout. Simple correlations using coal properties may be used but with caution to determine coal volatile release and burnout at high temperature and rapid heating conditions.

Jan 1, 1991

By Nguyen V. V

The development of structural defects in the overburden material immediately behind a production blast was studied using surface and subsurface techniques. A significant increase in vertical and horizontal fracture intensity was recorded. The extent of fracturing into the highwall appeared to be dependent on the structural and petrologic characteristics of the various lithological units and the relative position of the explosive charges. A shallow zone of disruption to a depth of 10 m and extending to around 30 m from the newly formed highwall crest was recorded. Horizontal fractures in lower units of the overburden sequence were recorded at distances up to 50 m from the new highwall Face.

Jan 1, 1981

By K Matsui, R N. Gupta, H Shimada

Roof falls and failures of powered supports were major threats at longwall face. Abnormal geological conditions were caused roof falls and shield damage. Therefore continuous monitoring and analysis of strata behaviour was imperative on real time for forecasting adverse behaviour. Novel PXI instrumentation system was successfully developed for continuous monitoring and analysis of supports pressure, leg closure and gate roads convergence. However, this paper briefly examines the novel gate roads convergence monitoring system with field applications.

Jan 1, 2003

Inefficient conveyors suffer carryback, leading to the build-up of materials on idlers, and other expensive components. They spill and leak material at loading zones and transfer points, causing accumulations that can damage the belt, wear moving components, and increase both cleanup labor and maintenance expense. They wander or mistrack, spilling material and en- dangering personnel and conveyor components, including the belt itself. And through these inefficiencies, they multiply an operation's hidden costs-the dollars lost because of missed production, of increased downtime, of the expense for the replacement of prematurely worn or damaged equipment. In this paper, the author will examine the importance of belt conveyors to mines and process plants He will trace the state-of-the-art in systems for cleaning belts, and controlling the release of fugitive material from conveyor transfer points, by exploring the roots of the problems, and demonstrating solutions that have been proven to be effective. Included in these systems to improve material handling are transfer point stabilization and sealing systems, dual belt cleaning systems, and belt training idlers.

Jan 1, 1991

In Australia, current production of rare earth element (REE) minerals, monazite and xenotime, occurs as by-product from titanium-enriched placers and beach sands. Undeveloped REE resources are associated with carbonatites, alkaline igneous rocks, pegmatites, phosphorites, cemented fluvial sandstones, and uranium mineralisations. The REE are held within a range of minerals including silicates, phosphates, a1uminophosphates, carbonates, and oxides. The development of these REE resources may require new processing and extraction methods. The distribution of REE in the currently mined ore minerals, monazite and bastnaesite, does not match that requested by the market. Exploration for new REE resources should be focused on ores with more marketable REE distributions, particularly with heavy REE, neodymium, samarium, europium and yttrium enrichments. Such ores occur within alkaline igneous rocks, in laterites overlying carbonatites and alkaline igneous rocks, and in placers derived from low-grade regional and contact metamorphic sediments. Lateritic REE deposits may be easily and economically mined by shovel in open pits and are unlikely to require extensive crushing and milling. In addition, lateritic REE clay deposits may be processed by simple hydrometallurgicaltreatment mehtods.

Jan 1, 1991

By Sims D. A

This paper primarily describes the application of geology to the different mining methods employed in a large underground mine. The steeply dipping stratiform Silver/Lead/Zinc mineralisation at Mount Isa include up to 28 mineable orebodies. The orebodiea are mined by cut and fill, sublevel benching and sublevel open stoping; the method chosen depending mainly on orebody geomechanics.The sources and methods of data collection, and the interpretation process undertaken, are described. The paper emphasises the different geological input required, by each individual mining method, to provide the necessary production and strata control. This input contributes significantly to the success and efficiency of the operations.

Jan 1, 1990

By Wright S

The feed to the Cockle Creek Imperial Smelting Furnace consists of mixed Pb/Zn con- centrates and lead sulphate-containing elec- trolytic zinc plant residues. Roasting was investigated as a means of desulphurizing the feed to less than 1%. Laboratory studies showed that two process streams were required in which concentrates containing 20% Pb were roasted separately from the leach residues. The residues along with fume from the roast- ing and a portion of concentrate were desul- phurized by means of the roast reduction reaction. Conditions were defined to give

Jan 1, 1986

The recent installation of top gas temperature probes in blast furnaces at Australian Iron & Steel Pty. Ltd. - Port Kembla, has provided the means for studying radial gas flow distribution in blast furnace shafts. This paper describes the top gas temperature probes and outlines their development and results of initial studies aimed at obtaining a suitable relationships between temperature profiles and furnace parameters. The effects of various combinations of burden materials have been outlined by the results reported. The use of probes has also helped to clarify the effect of casting cycles on furnace operation leading to increased emphasis on the reduction of the interval between gun-up and drill-out. Areas for future studies are also broadly Outlined.

Jan 1, 1975

By Flann R. C

A small modification to current industrial practice should lead to better nickel powders for use in alloying, electroplating, and powder metallurgy. Nickel powder compacts sold for alloying are not always suitable for electroplating applications, since some presently used commercial powders will expand on sintering. Further, such nickel powders are unsuitable for use in the production of powder metal parts, because of expansion during heating of the near-net-shape preforms. Research in these laboratories has enabled the elimination of expansion, and led to techniques for the production of compacts suitable, in particular, for commercial use in both alloying and electroplating. The techniques include: powder pretreatment, cold pressing and sintering, hot pressing, and hot pressing and sintering. In this way compacts are readily prepared with densities of at least 93 per cent of solid nickel, and these, when used as anodes in Watts general purpose and bright baths, give both cathode current and plating efficiencies of 90-98 per cent.

Jan 1, 1979

By Bayly MG, Harris JA

The current operational practice at the Territory Enterprises Pty, Limited uranium oxide plant,, and some aspects of researc$ and development work at Rum Jungle are outlined with pertinent comments on some overseas practices.

Jan 1, 1968

By Brent A. D, Olsen a. H, Mayfield P. L J, Grazier P. E

Concentrates produced from MnO2 and Fe203 ore fines have been targeted as potential feedstocks for direct metallurgical processing. Prereduction of pyrolusite-rich Mn02 sands to MnO has been investigated in batch and continuous experimental bubbling fluidised beds using CO-H2 reducing gas mixtures. This process has been found to produce a high grade feedstock suitable for smelting to ferroalloys or acid digestion for chemicals production. Similarly, production of highly metallised direct reduced iron (DRI) from hematite ore fines has also been investigated in batch bubbling bed reactors. Programs to characterise the reduction kinetics, fluidisation behaviour and defluidisation phenomena for both feedstocks are currently in progress to enable optimum process conditions to be determined.

Jan 1, 1995

The kinetics of desorption of nitrogen from molten iron were investigated using the electromagnetic levitation technique. The respective influences of gas flow rate and surface active element (S) were examined. A second order behaviour with respect to the nitrogen concentration in the melt prevailed at all experimental conditions. Sulphur had a marked inhibiting effect on the desorption rate. The experimental results on the rates of nitrogen desorption have been interpreted with the aid of a reaction mechanism consisting of a sequence of elementary steps.

Jan 1, 1991

By I Thin, I Sheppard

Resin encapsulated rock bolting practices have been adopted by Mount Isa Mines since the early-1980s. Fully encapsulated rock bolt systems meet designated requirements for long-term ground support in the mines. A variety of rock bolts, resins and installation methods have been utilised over this period in underground mining. As a parallel to this evolving application, Mount Isa Mines have tested various resin encapsulated rock bolt systems. Testing has included routine underground pull testing and the development and implementation of the push test for the entire encapsulated bolt length. The latter test enables a greater understanding and representation to be had of the overall mixing, level of encapsulation and capacity of the system. Rock mechanics at Mount Isa Mines undertake evaluation of new bolt systems that become available, in addition to the maintenance of compliance with quality control measures for the existing systems. Improved methods of installation and systems are also investigated to further the cost-effective nature and minimise risks associated with resin rock bolt practices.

Jan 1, 2002

By D Lawie

Prior to resource modelling, sample scale data is normally grouped into spatial domains that reflect zones of homogenous properties. These domains are usually based on a combination of grade and other variables that reflect, for example, geology and alteration, or variables known to correlate with properties of the samples that affect downstream processing. Domaining and wire-framing sample scale data is a time intensive task and it is difficult to track more than a few variables simultaneously while establishing domain boundaries. This is especially the case in operations with complex data, for example, a combination of multi-element assaying of total element concentrations, and/or phase specific assaying such as sulfide sulfur, carbonate carbon, cyanide available gold, and/or downhole geophysical measurements. To minimise unintentionally grouping samples of contrasting properties within the same domain, unsupervised statistical methods are available that can automatically identify samples atypical of the domain, both as univariate tests, and as tests that take correlation within the domain into account. Unsupervised methods in this context means methods of identifying atypical samples that require just the selection of the domain and input variables. Thresholds are derived robustly from the data itself, and the results are therefore repeatable and operator independent. Atypical samples may be thought of as outliers, ie, samples that are separated from the ‘majority’ of the data. If these atypical samples are themselves spatially associated, they may be allocated to an alternative existing domain or allocated to a new domain. Care should always be taken to ensure that identified outliers are due to meaningful causes and not due to data coding and storage errors, although the identification of the latter is still valuable. *This is an abstract only. No paper was prepared for this abstract.*

Sep 5, 2011