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By D V. Boger

The use of chemical additives to initiate such processes as particulate separation through flotation or dewatering through flocculation, is common in the mining industry. The dosing of additives is none the less poorly controlled from a process control viewpoint and it is perhaps fortuitous that over-dosing or misuse of chemicals is rarely catastrophic to the production cycle. In many cases, such events would go undetected if it were not for economic considerations. Recently, the advent of orebodies with finer mineral disseminations and the push for greater efficiencies in both production and tailing disposal have resulted in the need for greater control of the dosing and utilisation of chemical additives. The need to grind at higher pulp densities and to finer sizes and to dewater to higher solid contents are but two examples that require a more stringent understanding of the true role of additives in controlling the rheology of suspensions and the influence of additives on the surface chemistry of particles. The inter-relationship between the surface chemistry of particles and the role of additives in controlling suspension rheology is now well understood for systems in which the average particle shape in the mixture is spherical or close to spherical. Luckily, this is the case for a large number of systems in the mining industry and the true role of typical additives in these systems will be explored. Difficulties arise for suspensions containing clays or other platey or needle shaped minerals and in many cases, quite small quantities of platey minerals dominate the rheology of suspensions. The role of additives in controlling the rheology of asymmetric particle systems is more complex but the effect of the additive in changing particle alignment in solution is the key to understanding suspension behaviour. The manipulation of the rheology of asymmetric particle systems will also be explored.

Jan 1, 1998

The Electricity Commission of New South Wales is the largest single user of coal in the State, burning some 8.5 million tonnes during 1972-73. This coal is converted in power stations into electrical energy which is then distributed throughout the State and supplies the electricity requirements of 99% of users in New South Wales. Barring any major change in energy consumption growth, or change in the current mode of power generation, the consumption of coal by the Commission is estimated to have a doubling period of from 10 to 14 years. Coal is used to generate up to 87% of the electrical energy sold, the balance being obtained from hydro gen- eration, mainly in the Snowy Mountains, and, to a much smaller extent, from diesel generation at Broken Hill. A very large proportion of this coal is consumed in pulverised fuel boilers in the Commission's power stations, located mainly on the various coalfields of New South Wales. Coal supplies are drawn from a large number of mines, some owned or controlled by the Commission, others being owned by public companies. The coals used, originate from at least ten different seams located in the northern, western and southern coalfields of New South Wales, and therefore have a wide variety of properties and characteristics. To ensure an adequate fuel supply well into the future, the Commission is continuously engaged in coal prospecting in various areas. Bore data is used in assessing coal reserves and is also the basis of economic studies for their possible future exploitation. The numerous coal cores obtained during drilling operations are carefully tested and analysed in order to assess their suitability for power generation purposes, and to provide data for the design and operation of boiler plant using these coals. In existing power stations coal deliveries are systematically sampled and tested for quality control, for pay- ment of purchases based upon certain quality parameters and to check for any possible plant operating or main- tenance problems that might arise from the use of the particular coals. Almost all the properties of coal that may be necessary in the Commission's work are obtained using standard testing procedures carried out by the Commission's chemists, in laboratories located at the various power stations or at its Central Laboratories in Pyrmont. Where specialised analysis or testing is required, this is ordinarily undertaken on a commercial basis by outside bodies, expert in the particular field. The significance of the various properties of the coal for use in p.f. boilers is outlined and related to their proper application to boiler plant design and to plant operation.

Jan 1, 1975

By B Tessier

Checking the quality of a blast may be considered as subjective. Checking this quality will require measuring objective parameters. One of them is the resulting fragmentation of the blasted product. Numerous fragmentation æmeasuringÆ systems have been developed and marketed, based on image-processing. This presentation of FragScan will illustrate advantages and difficulties when using such a system. FragScan is essentially defending a policy of large and representative sampling. The purpose is to show how fragmentation is discriminating both productivity and profit of quarry operations on a blast-by blast basis. The next step will then be to ædriveÆ the blasting process to reach a æbetterÆ fragmentation. Other applications require the fragmentation as an essential result: this is the case for large boulders used in structure-reinforcement. Several case-studies have shown that FragScan can be used for quality-control, checking size-distribution of the product according to the requirements of the end-user. Only clear thinking about the precise use of such a æmeasurementÆ will further the success of this task.

Jan 1, 2001

By Rautio V

The mining sector has been automated and robotised very rapidly during the last few decades. The organisation of work, schedules and housing has been modernised from the traditional modes of industrial society toward the more flexible modes of

Jan 1, 1998

SINCE writing the above-mentioned paper, some further indicator cards have been taken from the No. 1 machine, and the writers believe that a reproduction of these cards will be interesting as illustrating the performance of the machine after fifteen month steady running, night and day, seven days per week and twenty-four hours per day, at the average speed of fifty-seven revolutions per minute (see Fig. 1, page 60). For the past twelve months no adjustment have been made in the valve setting, and the only repairs have been in connection with the springs of the poppet valves, and these but slight, the springs latterly having been removed. The cards illustrated were taken with one indicator, and, therefore, are not simultaneous, andmay show to some extent the yariations of individual strokes, and with that qualification may be taken as typical of the machine's average performance.In connection with some feed-water measurements of the winding engines a rough test was run with the two compressors, the Riedler and the Corliss, coupled to the condenser, and running at fifteen and fifty-seven revolutions per minute respectively, with the result of 15.9 pounds of steam per indicated horse power per hour. This result, though only approximate, seems to indicate that the No. 1 machine is running under the guaranteed consumption, and that it is capable of maintaining this under the severe conditions of everyday practice.

Jan 1, 1909

Australia is the dominant iron ore supplier to the Asian market, a position that began to emerge with the development of the Pilbara in the 1960s. Iron ore is now one of AustraliaÆs main commodity exports and is likely to remain so well into the future. The annual price negotiations are the focus of widespread comment and speculation by financial analysts, journalists and mining professionals. Much is written on the subject, but how much is understood? What is the process all about and what can mine managers learn from understanding the pricing mechanism? Every one of the major regional iron ore markets has its own characteristics. The focus here is Australian supply specifically to Asia, far and away the biggest and fastest-growing of these regional markets. The core of the paper reviews and explains the key elements and procedures that contribute to pricing iron ore in Asia, a market that has long been dominated by the Japanese steel mills (JSMs) and that is now feeling the full force generated by the rapid industrialisation of China. First, however, it is important to understand how this market has evolved over the past 40 years, and the key relationships that have shaped and continue to shape the iron ore price. A description of the essential technical and commercial factors follows. Each area is explained in some detail to provide an overall demonstration of the linkages and the importance of understanding the various influences on the pricing process.

Jan 1, 2006

By S C. Dominy

A high nugget effect and the presence of coarse gold characterises many vein-gold deposits. The effective sampling of these deposits is often difficult because of the relatively low concentrations involved and erratic nature of the gold. Geological complexity often compounds this effect. Underground development, in-fill drilling and bulk sampling/trial mining are often required to delineate Ore Reserves. Winzing is an historical technique that was used to gather geological and sampling data during underground exploration. It permits access to the mineralised structure below the current datum to help determine viability. Winzing has always been considered an arduous and dangerous task. Modern technology has led to the development of the Mobile Supersucker, essentially a giant vacuum cleaner. This system permits safe and efficient winzing activities, and allows the collection of bulk samples for grade estimation. Bulk samples from horizontal development have long been collected to help define mineable grade. However, when defining blocks below current development, there has been over-reliance on ineffective æsmall sampleÆ drill data. The Mobile Supersucker permits safe and cost-effective development of winzes and off-winze sublevels.

Jan 1, 2003

By Rolfe PR, Ellis BA, Clements RJ

Associated Minerals Consolidated Limited (AMC) is constructing a 112,500 tonne/yr synthetic rutile plant at Narngulu, near Geraldton in Western Australia. Design of the plant is based on the technology developed by AMC and utilised in its two existing plants at Capel in Western Australia. Ilmenite Feedstock for the plant will be sourced from AMC's mine at Eneabba and coal obtained from the Collie deposits. The plant is scheduled to come on stream in the second quarter of calendar 1987. The rationale of the decision to construct the Narngulu plant is examined against the background of the world market for high-Ti02 content feedstocks. Also provided is a detailed description of the plant and an examination of the technology used in process Design.

Jan 1, 1986

By J R. Kyle

The Deep Mill Level Zone (DMLZ) skarn Cu-Au deposit is the deepest explored part of the Ertsberg East Skarn System extending from the surface at 4200 m elevation to the DMLZ at 2900 to 2600 m. The DMLZ is hosted in an upper Cretaceous to lower Tertiary siliciclastic and carbonate succession adjacent to the 3 Ma Ertsberg pluton. Much of the DMLZ ore is hosted by mixed assemblages of siliciclastic and dolomitised carbonate strata that have been altered to Mg-rich skarn assemblages. Unaltered equivalent strata from a 300 m cored interval in the Yellow Valley Syncline were characterised petrographically and representative samples were analysed for major element compositions. These stratigraphic and chemical units are interpreted to be responsible for the varying skarn lithologies within the DMLZ. The dominant prograde skarn assemblages are controlled by protolith composition, notably the relative abundance of quartz, dolomite, and calcite within the protolith. Models based on isochemical metamorphism of mixed assemblages of quartz and dolomite suggest that the formation of the forsterite-diopside dominant skarn assemblages resulted in the greatest amount of pore space increase. DMLZ Cu-Au concentrations were locally controlled by host lithology, with structural features providing fluid pathways that focused the mineralising fluids. An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation.

Jan 1, 2008

By Somasundaran P

Controlled modification of mineral/liquid interfacial properties by adsorption is critical for mineral processing operations such as flotation, filtration, dispersion and flocculation. Ionic/nonionic surfactant mixtures usually show enhanced surface activity and salt tolerance over ionic surfactants, and this is especially beneficial for flotation of salt type minerals in which case dissolved multivalent cations in high concentrations usually cause loss of anionic surfactants by precipitation. Adsorption of nonionic/anionic surfactant mixtures on kaolinite has been studied with sodium dodecylsulfate as the anionic surfactant and octaethyleneglycol mono-n-dodecylether as the nonionic surfactant. Synergistic interaction between these surfactants was found to cause adsorption of the nonionic surfactant with its hydrophilic chains protruding into the bulk, leading to substantial changes in flotability and dispersion characteristics of kaolinite. Similarly, hydrophobicity changes are observed also' for silica particles upon adsorption of nonionic ethoxylated alcohols owing to possible changes in the orientation of the adsorbed surfactant species at the interface. Also, based on the results obtained with surfactant adsorption, a hydrophobically modified polymer was used successfully to disperse graphite particles in aqueous solution.

Jan 1, 1993

By Yu AB, Azahari HL

Indonesia has the largest coal reserves in the south-east Asian region. According to estimates from the World Energy Confer- ence, it has reserves of 18 billion mt lignite, 4.4 billion mt sub-bituminous coal and 774 million mt bituminous coal (Wyllie,1988). In recent years, substitution of coal for oil in power plants has been the goal of the Indonesian government since proven deposits of coal are about five times as large as national hydrocarbon reserves and most of Indonesia's power stations are still oil fired. Recently a coal fired power plant has been built in Java Barat, which will have a full capacity of about 3000 MW. It is intended to supply coal for this power plant from Bukit Asam mining area (South Sumatra). Coals from Bukit Asam - which are of the lignite or brown coal type - usually contain considerable moisture . It should be noted that reference to moisture in coal pertains to the total moisture content. This is comprised of what is commonly termed as equilibrium moisture and surface moisture. Surface moisture typically affects combustion process as well as pulveriser performance since it possibly influences the relative ease with which coal may be ground. In practice, the surface moisture produces agglomeration of the fines in the pulverising zone and reduces pulveriser drying capacity because of the inability to remove the fines as quickly as they are produced. This agglomeration has also the same effect as coarse coal during the combustion process because the surface area available for the chemical reaction is reduced, hence the combustion efficiency is also reduced. The influence of the moisture of some coals on their grindability (Hardgrove Grindability Index) has been previously correlated by several authors; some of them will be mentioned later. Those correlations, however, could not be immediately applied to any coal since it is still believed that there are other factors which influence the grindability of the coal, such as type and rank of the coal. The relationship between coal moisture content and its grindability has been investigated by Ellmann and Belter (1955). It was found that, for North Dakota lignites, the grindability varied as the moisture content changed. In Britain, Fitton, Hughes and Hurley (1957) stated that, for Bilsthorpe coal, over a wide range of free moisture content (from air-dried to about 30 per cent moisture), the Hardgrove Grindability Index (HGI) remains virtually unchanged. In addition to that, it was suggested that it would be slightly advantageous to dry the coal below its air-dried moisture content (at temperature ¦ 100¦C) to increase the ease with which coal could be ground, especially for low-volatile coal and high-volatile non-caking coal. Furthermore, it was also concluded that a broad relationship appeared between coal rank and Grindability.

Jan 1, 1993

The published safety policy of Mount Isa Mines Limited, together with details of the organisation and control techniques adopted by management to pursue an active safety programme within the company, is presented. The importance of communication by management through the organisational hierarchy and procedures instituted to ensure rapid and concise feedback on safety concerns are detailed. The paper also describes the role of the occupational health department and safety committees in assisting management to monitor the safety effort of supervisors and employees. Current safety performance levels are tabled together with details of some aspects of the programme on which safety effort will be concentrated in the future.

Jan 1, 1975

Concepts of facies are of proven worth in sedimentology, but have hitherto received little attention from volcanologists. The time is now ripe to develop facies schemes for volcanic products. This paper discusses possible facies applicable specifically to lava flows and ignimbrites, the intention being to explore possible approaches to the problem of recogniz- ing volcanic facies rather than attempting to develop a comprehensive facies scheme

Jan 1, 1987

Orebodies in the Mt. Charlotte - Hannans North Area N. & B. of the town of Kalgoorlie provide a marked'dontrast to the pyrite - telluride lodes of the Golden Mile, although both groups of orebodies appear to be fundamentally related. These highly siliceous telluride free orebodies N. of the Golden Mile are closely related to strong oblique faulting. The Golden Mile. lodes, while possessing an apparent over-all relationship to the oblique faults also have a close relationship to E.-dipping strike faults.

Jan 1, 1964

By J Parmenter

Issues around water û its quality, use, availability and environmental value û can be a major point of tension between mineral projects and local communities. Failure to manage these issues appropriately can jeopardise the obtaining of regulatory approvals for new projects and place at risk the æsocial licence to operateÆ of existing operations. Conversely, there may also be significant opportunities for companies to engage constructively with communities over water issues and to make a positive contribution to the sustainable development of these communities. Using case studies, this paper will explore the various types of social risks and opportunities associated with water and mineral resource development and identify key learnings relating to the management of these issues.

Jan 1, 2006

The paper presents two methods for periodical identification of the dependence between haulage speed and loading torque of the shearer for periodical corrections of control algorithms. These algorithms are useful for working with small microprocessor-based systems. The paper is concluded with results of identification using above methodsand with discussion about their merits and demerits. The longwall mining system is the basic exploita-tion system used in coal mining in Poland. The quantity of coal produced by this system, using a shearer loader as a cutter-loader machine is esti-mated at 170 million tones per year. For this rea-son scientific research concerning these machines is of major practical significance.

Jan 1, 1985

During the 22 years that Isa Mine has been formally involved in accident prevention, it has succeeded in reducing its lost time injury frequency rate by 70 per cent. At present its performance compares very favourably with that of other heavy industries and in particular that of other underground metalliferous mines. When reductions such as this are recorded, people want to know how it is achieved. No doubt it is assumed that if an organisation can maintain a consistent performance in accident reduction, it must have developed a panacea for the prevention of industrial injuries. This assumption would not be in accordance with the facts in the case of Isa Mine which has achieved its record through plain hard work and plenty of it.

Jan 1, 1975

First of all, I should like to thank you for theopportunity to be with you tonight and tocongratulate the Kalgoorlie and Perth branchesof the Australasian Institute of Mining andMetallurgy in initiating this most importantConference.It could not have been better timed.Gold is riding a crest of the wave, leading theresurgence in the State's mining industry.The strong and stable economic policies whichhave been pursued both by the Burke LabourGovernment in this State and by the HawkeGovernment in Canberra, whilst they have ofcourse only been part of the reason for thestrong recovery in the mining industry - a l o tof it being due t o international factors - havecertainly assisted and ensured that the miningindustry in this state has been able to takefull advantage of the changed world situation.

Jan 1, 1984

As world demand for various minerals increases the mining industry in its endeavour to satisfy this demand will, eventually,look to the extraction of orebodies which previously may have been uneconomical to mine. These orebodies may be of two types. Firstly, new low grade orebodies and secondly, remnant sections of previously mined orebodies. Some of the factors relative to remnant mining operations are discussed and the potent- ial of remnant mining in providing an important contribution to future world metal production is considered.

Jan 1, 1975

By Canterford JH

Current and future methods of data acquisition in hydrometallurgy are reviewed. Hydrometallurgical operations involve a wide range of chemical and physical processes for the recovery of metals and other products from ores and concentrates. Control of such operations requires information on the different liquid/solid and liquid/liquid mixtures being processed. Continuous. data acqui-sition for the liquid phases uses procedures already commercially exploited in other types of chemical plant. The major problem is the lack of robustness of measuring probes. Continuous analysis of the solid phases is much more difficult to-achieve because of the sampling and analytical techniques involved.

Jan 1, 1985