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By Swift J. D

A key parameter affecting the performance of gravity thickeners in hydrometallurgical processing operations is the aggregation state of the feed after the addition of a flocculant. New procedures which measure the settling ratelsize relationship and the size distribution of aggregates in their process liquors have been used to quantify the aggregation state of the feedwell, overflow and underflow streams in a tailings thickener. The data obtained have been related to the thickener's operation and to a change in the flocculant dosage. A comparison is also made between the settling rate/size relationships determined with these new procedures and the mud-line settling rates from cylinder tests.

Jan 1, 1991

By M Hassall

There is a plethora of activities that have been, and continue to be, performed to improve the health, safety and well-being of workers involved in resource industry activities. These activities include implementation of risk management systems, performing risk assessments, constructing bow-ties, implementing critical control management systems, undertaking personal, process and functional safety initiatives, implementing psychological and physical health as well as industrial hygiene programs. Despite the significant work that has occurred over the last several decades, unacceptable levels of fatalities, injuries and illnesses continue to persist as evidenced by Safe Work Australia statistics.

Apr 16, 2024

By D Akis, A Clark

The Lihir gold operation, located in the New Ireland Province of Papua New Guinea (PNG), approximately 900 km north of Port Moresby, was commissioned in 1997 under the management of the Lihir Management Company, a subsidiary of Rio Tinto. This management period ended in 2005 with Lihir Gold Limited (LGL) becoming self-managed. LGL is now the largest listed company in PNG and a top tier mining company in Australia. The focus of the operation since 2005 has been to take advantage of strong market conditions to increase cash flow while driving operating costs into the lowest quartile of gold producers. During this period production has increased through capital expansions, most notably with the addition of a flotation circuit, and through culture change and efficiency improvements. The next step forward for the Lihir operation is a major plant upgrade to increase production to an average of around one million ounces per annum by matching the ore processing rate to the ore mining rate. The key benefits of this project will be the addition of approximately 240 000 ounces per annum of gold production, the access to an additional one million ounces of gold and the ability to meet all stockpiling requirements. The Lihir operation has come out of the boom period in a strong position, is undertaking a major upgrade at a time when prices are low and labour is available, and will be positioned to take advantage of future opportunities as they arise.

Jan 1, 2009

In the Illawarra District of New South Wales, Mines were traditionally developed from the seabord. The advantages were close access to the working faces and a minimal depth of cover. Travelling times to the working faces have become prohibitive in many cases due to progressive westward development of the mines. As a result, additional vent- ilation shafts were sunk to service existing mines and new mines were established west of the Illawarra escarpment. Mining operations west of the escarpment are now being conducted at an increasing depth of cover and can be effected by gas related problems such as high seam gas emission rates and gas outbursts.

Jan 1, 1983

By J Tuma

Technical measurements are an integral part of research and development of new technical devices. Now they are also an integral part of production too, especially as a part of quality control systems. More new problems started with they applications up, like storing and following preservation of big data files. Many problems are also with processing of the measurement results, especially to be up to standards of ISO 9000 normative. It includes basic data about the measurement (structured data) and measurement outputs (huge data streams). Using database systems looks as good idea, because of structured measurement data and they processing. They were developed more concepts of database measurement system support during the research project MSM 272300012. It was decided to develop specialised measurement systems, on the base of experiments and experiences with they use in operating conditions. It proved to be wrong to develop general system, because of compound operating and long response of the system. And it is not possible to use these systems for mass production systems. The problem of data storing is not as easy to be answered, because of dependence on used technical devices. During realisation the measurement system for gearbox noise measurement are data stored to the database, because used analyser system PULSE (Brnel and Kjµr Co) is open structure and can cooperate with other software systems. Anyhow the data streams are not longer (after compression) than the Memo data type, in practical use increases the data file too fast (about hundreds MB daily). Therefore we must include a special supervisory system for administration and creating data files to the system. Nevertheless the used system MS-Access supports data files up to 1 GB, for practical application is better if the file size do not exceed the capacity of CD-ROM disc.

Jan 1, 2003

By Kubo H, Kubita K, Morinara M

A quantitative method for predicting the mechanical properties of zinc alloys is proposed on the basis of the molecular orbital calculation of electronic structures. A new parameter which is the s-orbital energy level, Mk , of alloying elements in zinc was introduced into this method. This Mk parameter correlates with the electronegativity and the atomic radius of elements. The compositional average of this parameter varied linearly with the tensile strength and the hardness of commercial alloys and some alloys developed by Mitsui. This electronic method was very convenient in designing high performance zinc alloys efficiently.

Jan 1, 1993

Prediction of large-scale underground opening stability in quite complex mining circumstances is being undertaken on a routine basis at The Zinc Corporation, Limited, (ZC) and New Broken Hill Consolidated Limited (NBHC) Broken Hill, Australia. A three- dimensional numerical modelling technique has been developed that gives good correspondence with the observed behaviour in many stopes. New insights into the rock mechanics of under- ground mining are flowing from this work. The modelling practice can be taught to engineers in a reasonable time-frame. In-house computing facilities including graphics workstations are needed. The RMS software is designed to be user-friendly and very robust.

Jan 1, 1983

By K Heiskanen, R A. Grau

Gas velocity (Jg) measurements conducted close to the froth-pulp interface over the cross-section of a flotation cell reveal how efficiently the incoming air is being dispersed throughout the volume of the cell. Furthermore, measurements of Jg at deepest locations in the cell provide valuable information about air recirculation and dispersion conditions in the bulk volume of the cell. Gas velocity in flotation cells has predominantly been measured by a transient capture of gas in a graduated probe. In this project, a new sensor for measuring gas velocity in an on-line manner was developed. A probe is partially immersed in the flotation machine, below the froth-liquid interface. The probe is used to collect the rising air bubbles from the liquid phase. The liquid-froth interface is shifted into the probe under vacuum. A controlled vacuum is kept inside the probe. As air bubbles burst inside the probe, the excess of air is continuously removed from the probe via suction. The removed air is measured using a mass flow meter. The fully automated sensor allows us to continuously measure Jg at different location in a flotation machine. An experimental programme was carried out in a 10 cm diameter laboratory flotation column to determine the accuracy and repeatability of the automated sensor. The new sensor was used for evaluating gas dispersion conditions in a 215 litre transparent laboratory scale flotation cell. Gas velocity distributions along the radial and axial directions of the cell were measured over a wide range of operating conditions. The operating conditions in the cell were modified by altering impeller speed and air flow rate. Two different rotor-stator mechanisms were utilised to disperse the air in the cell, the MultiMix and the FreeFlow mechanism. In this paper, a description of the gas velocity sensor is given, and the results of the experimental work are discussed in detail.

Jan 1, 2005

Excessive use of computers in teaching, especially in self-learning programs, may destroy creativity and initiative. It is essential that engineers remain innovative to develop new technology. Safety legislation may have hindered the Development of mine managers. It may be necessary to develop two distinct streams of mining engineers. One should be biased towards human relations and safety, to 'be a certificated mine manager, and the other should be mathematically based as a high-technology mining engineer who would not necessarily qualify for a certificate of competency without a postgraduate course.

Jan 1, 1986

Mount Isa mine is the largest underground mine in Australia and is located 2,000 kilometres north-west of Brisbane. This mine has been in continuous operation since 1931 and in 1986/87 the silver/lead/zinc stream achieved the peak annual mining rate of 4.7 million tonnes. At present about fifteen different steeply dipping stratiform orebodies are being mined to maintain an annual production rate of around 3.0 million tonnes. Out of these, only two orebodies (2 & 5) are amenable to sub level open stoping (SLOS) type bulk mining methods. This year only 150,000 tonnes are scheduled from pillars and remnant areas but in future, more sources will be required to meet the budget production targets.

Jan 1, 1990

By Ciminelli VST

Thiourea leaching has been applied to a refractory gold concentrate previously treated by bacterial oxidation. Following the bio-oxidation, gold has been leached in acidic thiourea solutions, under different pH(1 - 2.4), thiourea concentrations (2 - 15 g/1), ferric ion concentrations (0.04 - 3 g/1) and temperatures (298 - 333 K). Through this procedure, it was possible to increase gold extraction from 40 to 77 per cent. The increase in temperature raised gold extraction and reduced reagent consumption. Sodium sulphite addition was also very effective in lowering thiourea consumption. Staged leaching operations with interstage acid washing and carbon-in-leach experiments were tested, in an attempt to increase gold extraction. The results of thiourea leaching were compared with those obtained with cyanidation.

Jan 1, 1993

The role of marketing in the development of a new project will be affected by political, commercial and technical pressures. Marketing success will be determined by the ability to predict and react to tomorrow's environment. In the Australian coal industry there is an emerging transition from production to marketing orientation. As a result, greater technical awareness of customer needs will be required. In particular, the industrial product nature of coal markets will need to be recognised. Greater attention will also need to be paid to product options and quality in mine planning. Marketing personnel will become more involved at every phase of the development of a new mine.

Jan 1, 1983

A laminar-flow furnace technique was used to study the combustion of 37-53 µm size fraction of Woodlawn copper concentrate containing 7.4 per cent zinc, 5.0 per cent lead and 22.5 per cent copper. Factors studied included the effect of time, temperature and the distribution of volatile elements between the panicles and the fume. Air was used for most of the work but a few tests were carried out using 1 per cent oxygen in nitrogen. Chemical analysis, X-ray diffraction, and scanning electron and optical microscopy of polished sections were used to characterize the reaction products.When the concentrate was combusted at low temperatures (800-900°C), the fume was rich in lead. At higher temperatures, this was diluled by increasing amounts of zinc and copper. 70 per cent of the zinc, 60 per cent of the lead and 40 per cent of the copper were found in the fume after oxidation at 1400°C. Lead, zinc and copper were present in the fume as anglesite (PbSO4), zincite (ZnO) and cuprite (Cu2O) respectively. The major phases present in the panicles were magnetite (Fe3O4) and/or cuprospinel (CuFe2O4), with some zincite and cuprite.Elemental copper was found in the particles oxidized in 1 per cent oxygen. Possible vapour species responsible for the vaporization are discussed.

Jan 1, 1985

By Clark IH

Numerical modelling is an effective aid for the planning and design of underground coal mines. With funding from the National Energy Research Development and Demonstration Program, CSIRO Division of Geomechanics has produced a workstation environment which will allow the Australian Coal Mining Industry access to a wide range of numerical design models. The emphasis is on usability and simplicity and the long-term aim is that the techniques should be used routinely at the mine site, so that, in the future, design of a new underground mine will routinely involve modelling of each proposed layout.Each of the five numerical analysis programs, FESOFt, FLAC, MNLAY, FEBLK and UDEC has both strengths and weaknesses. Some analyses with each program demonstrate areas when; observed in situ behaviour in underground coal mines has been successfully modelled, and the results of site monitoring provide a basis for comparison with the predictions of numerical models.

Jan 1, 1991

The implementation, during recent years, of the concept of distributing chilled water to improve cooling at the working faces represents a very important innovation for the mining world. In a logical extension to that concept it has been recognized that distribution of the cooling water at high pressure would provide a potential source of energy for driving water powered hydraulic machinery such as rockdrills, water jets for moving rock, and support props, in the workings. With this in mind, the Research Organization of the Chamber of Mines of South Africa is pursuing the development of such a dual system that will provide cooling in a deep mine and, at the same time, drive hydraulic machinery. A comprehensive design of such a system has been completed and has shown the concept to be entirely feasible technically using technologies currently available. A pilot system is working in a mine shaft 2000 m deep giving a pressure of 20 MPa at the bottom of the shaft and distributing the cold water into the workings at a pressure of 17 MPa. The system shows considerable potential for improving existing mining methods and will open the way for the development of new mining methods for deep mining operations.

Jan 1, 1986

It is no longer adequate when starting a new mine to simply select the best equipment. Today's competitive international commodity markets demand superior efficiency which requires systematic involvement of people in continual improvement of production and commercial processes. True Total Quality of Management (True TQM) principles provide an operating philosophy for maximising productivity and minimising unit costs of output. The presentation will show the practical and successful use of these principles. This paper will introduce the case study and provide background material on True TQM.

Jan 1, 1995

By L C. Thompson

Biomineralisation is the process by which microorganisms mediate and catalyse inorganic reactions so as to form new mineral assemblages. The goal of biomineralisation as a remediation tool is to control microbial processes and their environment so as to sequester and immobilise specific toxic metals within exceptionally strong bonds of neo-formed mineral assemblages. In this way, the bound metals are no longer mobile within a geological time-scale. Applied biomineralisation uses microorganisms, which are isolated from a metal waste environment and are selected for their ability to rapidly catalyse neo-mineral development from dissolved or leachable metals. A typical waste environment will contain microbes that contribute to the mobilisation of metal contaminants as well as microbes that possess the potential for remineralising available metals. Selection and augmenting the correct combination of bacteria and eliminating the competing mineral degrading reactions are the key to applying biomineralisation as an in situ remediation process. Applied biomineralisation harnesses the microbesÆ ability to stabilise toxic soluble metals into non-mobile mineralassemblages. This paper will discuss and demonstrate the biomineralisation process through several case studies including the Summitville mine site in Colorado, the McCoy-Cove mine in Nevada, the Argonaut mine in California, and an historic lead site in Crooksville, Ohio.

Jan 1, 2004

By Aspinall T. O

Draglines have found wide application in strip mining coal seams down to 60m depth. A research Project funded through NERDDC has been underway during the past two years investigating the application of large draglines loading overburden into hoppers feeding into conveyor systems or off-highway trucks. This paper presents the preliminary results of these investigations and covers overburden characteristics, bucket spotting con- trol, bucket design, conceptual hopper systems, system application at representative mine sites, and broad process comparison. The studies have initiated new concepts in the extended use of draglines at deeper strip- ping depths. Alternate arrangements for dragline bucket rigging and bucket control aspects of dragline stripping operations offer productivity improvements. Extended use of existing draglines includes, draglines dumping into hoppers which feed large trucks or conveyors, trigger dump buckets rigging arrangements, and rear dump dragline buckets with integral grizzly bars. The paper details these suggestions, and points to specific areas where the most productive applied research is anticipated. Mine planning considerations detail the factors involved in selecting dragline bench heights in association with hopper operations.

Jan 1, 1989

Standard petrographic profiles for many Permian seams from New South Wales and Queensland have been drawn up. The standard profiles of seams of the same age and from one or more coalfields were used to compile an idealized or type seam sequence for those coals in which more than half the seam profiles were similar to one another. A marked similarity existed between at least 7 of the 10 type seam sequences formed. The configurations of the vitrite-plus-clarite contents of the plies of 95 per cent of the seams could be formed from different arrangements of 3 basic sequences: (i) a two-ply sequence with a lower vitrite-rich and an upper vitrite-poor ply; (ii) a two-ply sequence with a lower vitrite-poor and an upper vitrite-rich ply; and (iii) a four-ply sequence of 3 plies with vitrite-plus- clarite decreasing upwards, terminating in a vitrite- rich ply. The third basic sequence was very similar to a succession described for some British Carboniferous coals. Eighty per cent of the Australian Permian coal seams studied began with the first (i) basic type of sequence and are interpreted as originating in peat- forming areas which became progressively drier. More than half the seams were formed in an area with a stable depositional surface level which was subject to oscillations of small amplitude.. Many (30%) were formed in an area with a steadily rising depositional surface level.

Jan 1, 1969

Water is becoming an increasingly valuable commodity in Australia and the mining community is finding itself competing with pastoralists, domestic consumers and industry for access to what is an essential but finite resource. This paper will provide an overview of various legislative regimes in Australia governing water resources, and will review some of the fundamental issues which should be considered by mining companies when contracting with other parties for the supply of water. The paper will focus on mechanisms to secure access to water for mining purposes, and will deal with the following issues: Grants of water entitlements under legislation û (navigating the legislative requirements necessary to facilitate the taking and use of water for mining activities) The paper will focus on the key legislative requirements for securing access to water in Queensland, Western Australia, New South Wales, Victoria, South Australia, Tasmania and the Northern Territory, and will examine: compliance with regulatory processes for securing water entitlements through the grant of water allocations, licences and permits, etc; and dealings with water entitlements (ie statutory mechanisms for transferring water entitlements on a temporary or permanent basis). Securing access to water under water entitlements through contractual means. The paper will also review of some of the fundamental issues which should be considered by mining companies when contracting with holders of water entitlements for the supply of water from both groundwater and surface water sources. These issues include (inter alia): securing appropriate rights to take and use water in compliance with relevant legislation, the necessity to protect the validity of underlying water entitlements, ensuring the security of supply for the contract term, access rights affecting water entitlements and other important issues relating to the security of water entitlements for miners.

Jan 1, 2003