Search Documents

The explosion at Appin Colliery on July 24th, 1979, demonstrated the need for a large scale facility to simulate an underground type explosion and study its effects. The effects of an explosion cannot be established quantitat- ively using small scale models. A gallery was constructed for this purpose at Londonderry Centre and commissioned in Feb- ruary, 1980. It is 50 metres long, 2.7 metres in diameter, capable of withstanding an internal pressure of 210 kPa and is the only facility available for this purpose in Australia. The gallery has provided valuable inform- ation on blast effects of explosions in tunnels and is to be used for testing the performance of explosion arresting devices, further invest- igation of explosion effects, research into basic explosion phenomena and instrumentation development. Additionally, it will provide a demonstration facility for training purposes.

Jan 1, 1981

By K Biegaj

The paper describes challenges the author has encountered on Australian underground gold and nickel mines over the last eight years, when recovering high-grade gold/nickel bearing mine floor material with a mobile supersucker/giant vacuum cleaner and other equipment. Whilst for a number of years the mine floor vacuuming and other mine floor clean-down technologies have been accepted/adopted and are working well in other parts of the world and on the South Australian opal mines, regrettably, they have not yet gained acceptance of mining executives and mine managers of gold and metal mines in Australia, who still elect to leave the never to be recovered gold/metal behind or to put it plainly - waste it.For reporting purposes during the mining process, the portion of gold/metal included in calculation of ore reserves prior to obtaining capital funds for their development, continues to be camouflaged in various reconciliation and call factors. This approach, ie wasting of capitally developed and already broken ore stocks should be viewed by the shareholders as totally inappropriate to say the least, especially with the current gold and other metals prices.The author attempts to provide answers as to why the technology referred to above has not yet been accepted on Australian gold and metal mines and outlines the way forward.CITATION:Biegaj, K, 2012. Why do shareholders and mining executives allow mine managers to leave behind high-grade broken ore underground?, in Proceedings Narrow Vein Mining 2012 , pp 197-206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 26, 2012

This paper examines the cost and economic consequences of varying a number of key factors in the course of developing and operating new underground longwall coal mines with both shallow and deep cover in New South Wales. The economics of the project are assessed for the first 20 years of mine life using the discounted cash flow method with produc- tion and selling price being determined to provide break even costs for a range of minimum rates of return.

Jan 1, 1988

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

A study is presented of the theoretically possible initiation systems for outbursts and the subsequent propagation mechanism.Previous occurrences of outbursts and their correlation to the theoretical system are described. An estimation of the energy release from two energy sources, gas strain energy and rock/coal strain energy, is presented and the relative importance of each source in the severity of outbursts. Summary: The description of mechanisms of outbursting follows the examination of these phenomena at Collinsville in Bowen No. 2 mine and at Leichhardt Colliery, Blackwater. Quantitative material contained in the paper refers to Leichhardt Colliery, Blackwater. Clearly from the work carried out to date gas release has a major part to play in the out- bursting at both of these collieries. In the case of the December 1 1978 outburst at Leichhardt Colliery energy release estimates place gas strain energy release contributing eight times the energy of that from rock/coal strain energy. Even the normal outbursts at Leichhardt Colliery appear to show this trend. Estimates of energy released are for comparative purposes between gas and rock strain energy and the values obtained may be regarded as approximate.

Jan 1, 1980

By Liu Q, Siefken T. C, Misra V. N

The bubble size was measured in a laboratory flotation column. The effect of variables such as air flowrate, frother dosage and type, pulp density, particle size and water column height on the bubble size was investigated. The results show that an increase in either air flowrate or pulp density cause the bubble size to increase, while increases in water column height, frother dosage, surface tension or solid particle size cause the bubble size to reduce. Among the frother types tested, MIBC was found to be the most effective in reducing the bubble size.

Jan 1, 1992

By J A. Brown

Osborne Mine commenced hydraulic filling of three stopes in April 1999. Two of these stopes experienced barricade failures in July 1999 and January 2000. As a result, a review of hydraulic filling was commissioned in April 2000. The design of a trial of revised specifications and practices is in the final stages, prior to the trial commencing in mid-2002.

Jan 1, 2002

Copper refining electrolytes are maintained in the range 60-65¦C to ensure an efficient operation. The heat energy required to meet these temperatures has been traditionally derived from the electrical energy required for the electrolytic process and supplementary steam energy. In 1983, experiments were conducted at Copper Refineries Pty. Ltd. (CRL) to determine the effects of insulating the Tank House cells, and fully covering the cells. The results of these experiments showed conclusively that greatly reduced steam consumption would be required to maintain electrolyte temperatures. These positive results led to an Energy Conservation Programme for the Tank House, and this was implemented in 1984. A computerised cell cover monitoring system was developed, and is used to control cell coverage and fluid balance. The experimental work and the benefits obtained since implementation of the programme are discussed.

Jan 1, 1985

By D Beck, E Jones

The measurement and management of deformation in underground excavations is a key responsibility of geotechnical and mining engineers. A critical aspect of these roles is to ensure there is sufficient ground support capacity for the expected demand.Current methodologies for monitoring deformation and ground support serviceability-limits require measuring displacement at distinct points, or using visual observations. These current methods limit the assessment to a qualitative interpretation of deformation across the entire excavation.Recent advancements of Light Detection and Ranging (LiDar) technology permit a new method for monitoring deformation that allow a full 3D image of extended sections of an excavation to be precisely scanned. The results from the comparison with subsequent scans provide valuable information on the magnitude, direction and extent of regions exceeding the ground support serviceability-limits. This new method now provides a quantitative assessment across the entire excavation being monitored.The implementation of regular scanning has been demonstrated to be highly advantageous not only at mines with swelling or squeezing ground, but also at mines with rapid seismic induced deformation. The use of LiDar technology as a routine deformation measurement tool for geotechnical and mining engineers (and further applications) are discussed in more detail in this paper.CITATION:Jones, E and Beck, D, 2017. The use of 3D laser scanning for deformation monitoring in underground mines, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 267–270 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By Raymond G. F

Geostatistics - a tool used by geologists and mine planning engineers to estimate grades and rapidly evaluate alternative mining strategies has reached an advanced stage of development for the silver-lead-zinc orebodies at Isa and Hilton Mines. Geostatistics has been used for over a decade in the massive copper orebodies but the stratiform lead-zinc orebodies are much more complex and provided a completely different set of challenges. Recent increases in computer processing speed and power provided by the Integrated Mine Planning System (IMPS) has aided the development of the geostatistics package. Also the formation of a project team and the subsequent in-house development which has drawn together the expertise of geologists, engineers and system analysts has contributed significantly to the success of the project.The most important feature of any approach to modelling the lead-zinc orebodies is that the kriging search must consider estimate and sample points according to their positions relative to bedding surfaces. By transforming co-ordinates as perpendicular offsets from a plane representing the local strike and dip, it is possible to elongate the ellipsoidal influence to parallel bedding. By interactively modelling surfaces using CAD facilities and then specifying these surfaces as 'hard' or 'soft' boundaries, the geologist has complete control over the kriging process.

Jan 1, 1993

By Mckenzie CK

Delay scatter, although widely recognised, has rarely been studied with the aim of critically reviewing blast designs. With current trends towards increased deck charging, and the effect on the number of separate delays in blast designs, delay scatter is shown to have a rather profound influence on the control of initiation sequence and the ability to successfully con- duct pre-splitting and smooth blasting. Determination of realistic delay scatter distributions is the first step towards application to blast design. Delay scatter must be evaluated in terms of deviation from the nominal time, not in terms of deviation from the batch mean, since the latter is not usually known without specific testing, requiring accurate timing instrumentation. Computer programs using Monte Carlo simulation can then be developed to investigate the probabilities of out-of-sequence initi- ation or near-simultaneous initiation within any specified interval. The procedures have been applied to both production and development blast designs in Australia and Chile to improve initiation sequence control and to rationalise and simplify blast designs.

Jan 1, 1988

During the past 18 months a rock mechanics project has been in operation at Renison Limited. The project was established to identify and investigate key problem areas that would affect future production at the Renison mine. An in-house approach was adopted, using shall compact equignent, to investigate ground behaviour. Information on the rock stress field was considered to be particularly important for an understanding of ground behaviour. A high horizontal stress component exists, which enables large flat dipping spans of hanging wall to be opened up, with support being provided by post pillars. The amount of support provided by these post pillars has been found to be low.

Jan 1, 1982

By Dobos SK

The Black Ridge Gold Deposit is located in the northern part of the Clermont Goldfield, which is situated at the boundary of the Bowen Basin and Anakie Inlier, Queensland. The goldfield comprises a series of NNW-trending semi-isolated basins, which are tectonically aligned with the Denison Trough, the west-most division of the Bowen Basin (Fig. 1-1).The main stratigraphic units in the deposits in younging sequence are the Anakie Metamorphics, the early Permian Blair Athol Coal Measures, the late Permian(?) White Section, and the Tertiary basalts which are regionally widespread, and intruded by abundant mafic and felsic plugs.

Jan 1, 1990

By Slechta JJ

The performance of a hydrocyclone treating fine coal has been examined over a wide range of feed and operating conditions.The results were expressed in terms of partition curves from which the water split to the oversize flowstream,the corrected separation size and reduced partition curves were determined-.The following conclusions were obtained. (a) The water split to the oversize flowstream was found to be dependent upon the vortex finder and spigot diameters of the cyclone and the flowrate and solids content of the feed slurry. (b) The corrected separation size was dependent on the solids content of the feed,and the vortex finder and spigot diameters.The hydraulic pressure (or flowrate) of the feed slurry did not have a significant effect.This phenomenon could be explained in terms of crowding of the particles at the Spigot.

Jan 1, 1984

By Cox I

Raiseboring is a technique that has become popular in modem mining engineering since the early 1960s. A study has been undertaken at the University of Queensland to determine important factors affecting the optimum diameter of raisebored shafts, excluding local parameters such as the maximwn excavation size that a particular rock type can safely accommodate.This model is used to examine each of these factors and the results indicate that the optimum diameter for raisebored shafts is generally between four and six metres.

Jan 1, 1991

There exist many formulae for designing coal pillars. However, when applied to a given set of mining parameters, they lead to different pillar sizes and factors of safety. From the subsidence point of view, the pillars designed as protection pillars not only have to be stable, but also have to limit subsidence over them to a level acceptable to the structure being protected. The subsidence over a pillar of given width to height ratio depends upon the mining depth. A pillar may be stable, but the subsidence over it may be quite large and unacceptable for the structure. In many cases even though pillars may yield, they support the undermined strata and reduce surface subsidence. In addition, the yielding pillars eliminate peaks and troughs in the surface subsidence profile and reduce ground strains. In a given situation, whether a pillar yields or not depends primarily upon its width in relation to mining depth.

Jan 1, 1992

By Gemuts I, Hudson D. R

Massive sulphide mineralisation at the Miriam prospect, near Coolgardie, Western Australia, is fracture-controlled and associated with disseminated sulphides near the basal contact of an ultramafic lens. The lens is peridotitic in composition with a pyroxenitic zone at its base, and lies within a sequence of altered high-Mg basalts and pillowed tholeiitic basalts. Recrystallisation of the ultramafic rock has resulted in the development of secondary olivine. The average composition of the sulphide fraction of massive ore is Cu = 4.4%, Co = 0.3%, Ni = 23.0%, Fe = 31.8%, S = 40.6%, consisting of the supergene assemblage violarite-pyrite to a depth of 210 m.

Jan 1, 1973

In coal room and pillar, and pillar extraction panels, the sidewall conditions were investigated based on underground measurements and numerical simulations. Three-dimensional linear elastic models provided a useful and quick prediction of the amount of sidewall spalling. However, more complex constitutive models were required to simulate more accurately the extent of fracturing and its effect on the stress re-distribution. The input parameters of a Mohr-Coulomb model were determined by back-analysis of underground measurements, and the effect of the depth of the workings and the time dependent occcurrence of coal pillar fracturing were analyzed.

Jan 1, 1992

Comalco Limited has recently completed construction of a $50 million kaolin plant at the site of its bauxite mining and industrial minerals operations at Weipa. The plant will produce 100,000 tonnes per annum of coating grade kaolin for the paper industry.Comalco produced the first coating kaolin from the deposit in 1979 on a trial basis. Since then a variety of quality coating grades with specific particle ize distributions and brightness values have been prepared.Extensive drilling and bulk sampling of the deposit over eight years has shown that the orebody is large and of a high grade suitable for the production of premium quality coating kaolins.The processing plant technology was developed by Comalco in association with the European kaolin and equipment producer Amberger Kaolinwerke GmbH (AKW).The Weipa kaolin plant is the first of this size to be built in the Pacific Basin region and it will offer the region's paper-coating mills a stable and reliable source of high-quality kaolin, shipped from an established bulk loading port. The paper provides an overview of the development of the kaolin investment, the nature of the production process and details the project management procedure used for the design, construction and commissioning of the plant. Three areas of significant interest, the gas turbine fired pray dryer, the moving bridge shiploader and the use of aerobelt conveyors on the project are detailed.

Jan 1, 1988

By Soma T

Pyrite and Cu-concentrate were roasted in vertically suspended state in an externally heated tube. Tubes of three different lengths of reaction zone were used for three different reaction times. Roasted ores were submitted to chemical analysis and the extent of roasting reactions was determined. In case of pyrite, extent of roasting reactions was not affected much by reactor length and heating temperature (above 500¦C), but was considerably by ore/air ratio. Micro- scopic and XMA examinations led to the conclus- ion that pyrite particles decomposed to pyrrho- tite and then pyrrhotite was oxidized to give Fe-S-0 melt, magnetite and hematite. The extent of reaction was not uniform in all particles but had a wide distribution from unreacted pyrite to completely oxidized particles. Combustion of Cu-concentrate from Kuroko complex sulfide ore ) was unstable under a uniform wall temperature of 450¦C, but proceed- ed rapidly at temperatures above 500¦C. Sticking of roasted ores to the wall of the reaction tube induced choking of the tube, caused by melting of roasted ores, at tempera- tures above 950¦C. Enrichment of oxygen exterted less influence on reaction rate than heating temperature of the tube. Particle size of ore had a big effect on reaction rate.

Jan 1, 1980