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As an indication of the overall quality for the three periods the expected run of mine ashes are given. Operating Period R.O.M. Quality Years 1 - 4 22.0% Ash (db) Years 5 - 14 18.8% Ash (db) Years 15 - 20 17.3% Ash (db) The size distribution of the coal was found to be generally as predicted in the 1980 study. However the ash, particularly in the smaller fractions, was found to be higher due to the previously mentioned friable nature of contaminant material. Following evaluation of this additional information, the proposed washery design was reconsidered. Three basic process schemes were examined. 1. A jig with two-stage heavy medium cyclones and spirals for treatment of three different size ranges. 2. A heavy medium vessel, two-stage heavy medium cyclones and spirals for the different size fractions. 3. A jig for initial treatment of the total feed (that is all sizes) with single-stage heavy medium cyclones and spirals for rewashing of the intermediate and smaller size Fractions.

Jan 1, 1986

By R Crosbie, K C. Runge, E Tabosa, J K. McMaster

Flotation feed density is an operating parameter which is currently not well understood. Most models of flotation only incorporate its effect on particle residence time, but it is likely to have additional effects within both the pulp and froth phases of the machine. Test work was performed in MetsoÆs 3 m3 RCS test rig to investigate the effect of flotation feed density on metallurgical performance. The rig was operated at Rio TintoÆs Northparkes operation using flotation feed and scavenger tail. For each feed, tests were performed at different feed densities, and measurements were performed to estimate the pulp and froth recovery as well as other key flotation parameters (eg bubble size, turbulence and froth stability). Results of this test work have shown that the pulp density does affect key parameters of the flotation process in both the pulp and froth phases. Pulp phase kinetic rates decrease at high density and this is attributed to a reduction in the turbulence within the cell. Froth phase recovery, however, improves presumably because of a stabilising effect due to a greater loading of solids on bubble surfaces.There is a need for more research to be done to better understand these interactions so that metallurgists can determine the optimum flotation feed density to use at a particular operation, or within a section of a flotation circuit.CITATION:Runge, K C, Tabosa, E, Crosbie, R and McMaster, J K, 2012. Effect of flotation feed density on the operation of a flotation cell, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 171-178 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By Fyodorov A. N, Sorokin M. L, Komkov A. A

The Vanyukov Process is a bath smelting technology, that has been investigated for over 25 years and since 1977 has been in use on an industrial scale. Results of trials that have been carried out at the various pilot facilities over the past 15 years are considered in this paper. Both the main process aspects, design of the pilot furnaces and metal distributions are presented for consideration. Experience of the smelting of copper, copper-nickel, copper-zinc, nickel, lead, and pyrite concentrates is analysed.

Jan 1, 1992

Previous studies on the blast furnace raceway zone have been undertaken at three levels of scale, namely: laboratory models at low temperature, hot models which simulate coke combustion in the zone, and tests performed on operating and dismantled blast furnaces. This paper reviews the results of this published work on raceways in order to illustrate the factors which affect the raceway shape, size and combustion characteristics. As a result of the work it has been established that raceways are influenced by blast parameters such as velocity, temperature and chemistry, as well

Jan 1, 1981

By R Price

"Technology has the potential to revolutionise industries, work functions or businesses. One such technology in the mining industry is the deployment of automation in a modern autonomous haulage system (AHS). This paper examines a theoretical application of an AHS in a medium scale mine site. The cost-benefit commercial argument is particularly compelling, and the paper outlines metrics and future issues for consideration.Citation:Price, R, 2016. Autonomous Haulage Systems - the Business Case, in Proceedings Ninth AusIMM Open Pit Operators' Conference 2016, pp 11–17 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 15, 2016

By Stein A

The general mechanism of recrystallisation for cold worked metal is well established, and need be only briefly summarised with a few references to recent articles which clarify minor points. The types of extension, whether by stretching, drawing, hammering, rolling, etc., do not alter the general principles (1), although quantitative results may differ somewhat, particularly with regard to differences between the surface and interior of samples.These principles can be summarised as follows: The first stage in annealing is a recovery (sometimes known as relaxation) of physical properties such as hardness, elongation, etc., without any appearance of recrystallisation; the second stage involves a further alteration in physical properties, accompanying the formation of new recrystallised grains which replace the original structure; a possible third stage involves an increase in the grain size of the completely recrystallised structure by absorption of smaller grains by larger ones. These three stages will be referred to as recovery, recrystallisation, and grain growth. Depending on conditions, the three stages may be clearly marked or may occur more or less simultaneously.For a given annealing temperature, cold deformations below a certain amount fail to give recrystallisation, and the final structure consists of the original grains which have recovered and possibly become more equiaxed. When a certain deformation, critical for that annealing temperature, is given, recrystallisation can occur, and will give the maximum recrystallised grain size.Increasing deformations beyond this give progressively smaller grain sizes.For each material there is a minimum recrystallisation temperature, below which recrystallisation will not occur whatever the deformation or time of annealing. For a given deformation there is a temperature, critical for that deformation, below which recrystallisation will not occur, and above which it will take place with increasing rapidity.

Jan 1, 1947

This paper briefly reviews the background of mobile primary crushers and their current main areas of application. The benefits of applying mobile primary crushing and belt conveying systems are analysed. The impacts of applying such systems to different steps of the mine process are discussed, including mine development and planning. Application examples are used for demonstrating further possibilities to apply mobile primary crushing and belt conveying systems in mining projects successfully.

Jan 1, 2007

SOME notes on the works of the Electrolytic Refining and Smelting Company of Australia will no doubt be of interest to members of the Institute, more especially as much of the work is new to Australasia.As many of the members who may read this paper have not been in a position to visit works of this kind, and are consequently not thoroughly acquainted with all the operations carried on, the author has taken the liberty, in some cases, to enter into explanation which would otherwise be unnecessary.The works are situated at Port Kembla (New SouthWales), about fifty miles south of Sydney, and are approachable both by rail and water. The Government has recently built a low-level jetty upwards of five hundred feet long, and intends installing at an early date an electrically operated portable crane to facilitate the handling of material to and from the boats. Thi.s will mean a considerable reduction in the length of time that boats are laid up at the jetty. There are also under construction two breakwaters, which, when complete, will materially assist shipping operations. The works as they exist are capable of turning out 1200 long tons of refined copper per month. It is gratifying here to note the unqualified success with whichthe E.S.A. refined copper met with on first being put on the market.

Jan 1, 1911

By Thomas L. J

A series of tests on rock stress measurement devices used with the overcoring method indicated that improvements could be made in their construction. A prototype inclusion cell was developed with strain gauge rosettes bonded to a 0.05 mm thickness stainless steel sheet which was formed into a cylinder around two end pieces. The finished diameter was slightly larger than previous cells so that the thinner plate and the reduced annulus of Araldite cement in the installation borehole gave a better response in the laboratory than the other cells tested, especially in simulated bedded rock. It was less affected by inhomogeneity and temperature changes. Its high sensitivity should make it suitable for both absolute stress measurement and field monitoring. A table of comparative readings is given for the new cell and for four other devices used in simulated in-situ rock conditions.

Jan 1, 1992

By W Y. Guo, L X. Chen, D X. Zhang

To obtain the rock type-I crack propagation process accurately, a novel fixture is used to make the prefabricated crack of rock propagation along the predetermined direction. In this study, the crack propagation process of rock is monitored with the digital image correlation method (DICM), and a mechanical model of crack directional propagation was established. The results show that the simple crack directional propagation device can effectively realise the stable propagation of type-I crack along the predetermined direction, the crack initiation angle is less than 10°, and the deviation between the peak strength of crack propagation calculated by a simplified mechanical model and the tensile strength of Brazilian splitting is 22.76 per cent and 7.53 per cent, respectively. According to the deformation field evolution law, crack propagation can be divided into three stages: microcrack development, main crack propagation, and main crack propagation. As for the rock type-I crack initiation and propagation mechanism, before reaching the peak strength, the prefabricated crack tip is subjected to maximum tensile stress; the elastic energy increases rapidly, and the dissipation energy increases slowly; after the peak strength, elastic energy exceeds its energy storage limit and released rapidly, and most of the input energy is converted into dissipation energy, which makes the crack propagation rapidly. The crack directional propagation device will be further optimised and improved, and it is expected to provide a new method for the study of crack propagation mechanism, rock failure precursor information and crack arrest principle, etc. It will also provide theoretical references for the optimisation of coal strata directional blasting, fracturing, fracture arrest, and other related technologies in geotechnical engineering.

Nov 29, 2022

By W J. Bruckard

In Australia, ilmenite is produced from beach sand deposits. These deposits contain varying quantities of the valuable minerals zircon, rutile and ilmenite, along with a variety of other minerals. The valuable minerals are upgraded using combinations of gravity, magnetic and electrostatic processing techniques to yield high-grade products. One of the penalty elements present in ilmenite concentrates is chromium, present mostly as chrome spinels. This mineral is particularly difficult to separate from ilmenite, as the properties of the two minerals are very similar in relation to the traditional separation processes. While the deposits which have been treated in Australia in the past have had only low levels of chromium present, many of the newer deposits contain much higher levels of contamination and, thus, there is an increasing need to develop robust processes to separate chrome spinel from the ilmenite. Flotation, which is a unit process with the potential to solve this problem, has surprisingly received little attention for this application. The literature suggests the research effort to characterise the general flotation properties of chromite (chrome spinel with high chromium content) has been extensive and a substantial amount of data is available. However, the problem of separating a small amount of chrome spinel from a large amount of ilmenite requires a different approach to that from separating chromite from siliceous gangue, which has been the main commercial focus of chromite flotation in the past. Much of the work done has been fundamental in nature and the results obtained are fairly inconsistent, as is the testwork completed at batch and pilot plant scale. While these inconsistencies have been attributed to the variable composition of the mineral, there is little evidence supporting this premise. Just as chrome spinel and ilmenite have similar physical characteristics, the flotation response of both minerals is also similar. This paper reviews the literature relating to the flotation of chrome spinel and presents a considered approach to the development of a robust flotation method to separate chrome spinel from ilmenite.

Jan 1, 2001

By Sano S, Ishikawa T, Nagaoka H, Hayashi Y, Hasegawa M

The stirred mill is regarded as one of the most efficient devices for micronising materials and has come to be actively used for preparation of fine particles. Recently, the demand for ultrafine particles was increased in many kinds of industries. In this paper, autogenous grinding to get submicron particles based on mutual friction feed material has been carried out using a stirred mill. The mill used was made of stainless steel and its volume was about 5.5 litres, and has 12 impeller blades. Sample used was limestone. In the present work, two operating parameters such as stirring speed and feed size of limestone were considered. The ground products were sieved in the size range from feed size to 325 mesh (45 lun), and from 45 to 0.17 pm the size distributions were measured by a laser diffraction and scattering method. The progress of grinding was evaluated by the increasing amount of submicron particles in products. As a result, the rotational speed of impeller with the minimum energy consumption to produce submicron particles was observed. It was found that the autogenous grinding with a stirred mill is an effective method for producing submicronized limestone.

Jan 1, 1993

An algorithm is described which leads directly to a unique set of coal washing parameters which, in two or more parallel streams, will give maximum yield of product at a given ash. This occurs when all parallel streams are washed to the same incremental ash. This strategy is shown to offer a considerable increase in yield compared to the simpler strategy of washing each stream to the same sumulative ash.

Jan 1, 1987

By M Hourn, G Anderson, V Lawson, P Voigt, D Mallah

As mine head grades decline and orebodies become more complex, traditional mineral processing techniques and flow sheets to achieve saleable concentrate become more difficult to design and construct. Mines with lower quality concentrates or concentrates with penalty elements are particularly under threat. The economics of such operations are far more susceptible to metal price fluctuations, concentrate treatment terms and the availability of other, cleaner concentrates. Additional value may be realised for these orebodies through improved recovery by producing a low grade middling concentrate for further processing, in conjunction with a saleable concentrate.The most economic effective way to reduce impurity levels is to do so as early as possible in the mining value chain. Technologies such as fine grinding and fine particle flotation are well established as effective methods for impurity rejection in mineral processing. What is often overlooked is how a hydrometallurgical process could also be integrated in the overall flow sheet to achieve higher overall recovery at the mill. In the base metals environment, this is probably because hydrometallurgical processes are associated with production of metal, or require the use of expensive and toxic precipitating agents once the minerals of interest are in solution. These processes can be very expensive, particularly with rising power costs and poor economies of scale in capital costs associated with low production rates from middling streams. Glencore Technology (GT) has recent experience in the treatment of middling and low grade concentrate streams and also tailings streams to complement a concentrator flow sheet in a refractory gold and base metals setting. The value proposition is the isolation of a low grade middling concentrate from the primary circuit or the tailings stream for upgrading to an intermediate product with an equal or higher grade than the primary concentrate to allow blending for sale. This allows the plant to operate on a more favourable part of the grade-recovery curve while avoiding the expense of metal production. For existing operations this is particularly attractive since it can be added to the flow sheet with no process interruptions. Two case studies are examined showing flow sheets and costings to arrive at the value proposition of the GT low grade treatment flow sheet.CITATION:Voigt, P, Hourn, M, Lawson, V, Anderson, G and Mallah, D, 2017. Economic recovery and upgrade of metals from middling and tailing streams, in Proceedings MetPlant 2017, pp 289–297 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

An efficient stores organisation is essential for an efficient undertaking. Unless the stores organisation is able to meet the requirements of its requisitioners promptly and economically, the undertaking as a whole cannot function efficiently.Delays or errors in supply of material, or substitution due to lack of material availability from the stores are costly and must be eliminated. This then makes the objective of a store, to supply on demand at the cheapest possible price, those items of stock which it is organised to carry, also to procure as quickly as possible and at the lowest price those special items required which are not normally carried in stock. To do this it is necessary to set up a stores organisation consistent with the size and requirements of the undertaking. Stores organisations vary with the nature of the undertaking they are designed to serve. In the case of the Broken Hill Associated Smelters Pty. Ltd., an organisation has been established to meet the operating and maintenance requirements of the Port Pirie Works. These embrace the particularly wide range 0:1; activities associated with roasting" blast furnacing and refining the lead concentrates from the Broken Hill Mines in a continuous metallurgical process producing a variety of refined metals; also many associated activities including power production and engineering maintenance and construction.

Jan 1, 1951

By G Cormack

By designing comminution circuits for mineral liberation rather than the final recovery process and by using high mass pull gravity recovery, the concept of underground processing has become a reality. Gekko has found that many ores respond favourably to fine crushing with either high pressure grinding rolls or vertical shaft impactors which when combined with the InLine Pressure Jig gravity separator and coarse flotation results in a narrow, low-head, compact processing plant that can be sensibly fitted in existing underground openings. The focus on fine crushing reduces the power requirements of the plant to approximately 5 kWh/t for a capacity of up to 20 t/h run of mine ore feed. The use of water recycle systems places no extra load on the mineÆs normal water handling system. GekkoÆs underground processing plant, the æPythonÆ, has been designed to be towed down the decline or lowered down a shaft and is capable of being installed in sloping, non-linear drives for placement close to the working face. The overall benefit to mining companies of this concept has been estimated to be a significant operating cost-saving, lower cut-off grade and a significantly smaller environmental footprint.

Jan 1, 2008

Over the last 20 years the mining industry has played a key role in the further development of many Central Queensland and New South Wales communities. The number of people who are employed by the coal mining industry, the number of transient residents, shift work and the town facilities have all contributed to how the community views the coal mining industry. As the coal mining boom continues and the mining communities continue to grow more emphasis is needed to address the community concerns, specifically the socio-economic and environmental impacts that the coal mining companies may have on these communities. Central Queensland coal mining operations are situated in the Bowen Basin. Many of the towns in the region have been developed specifically for the coal mining industry with 13 - 50 per cent (Australian Bureau of Statistics, 2006) of people living in the communities being directly employed by the mines. The introduction of shift work, differing rosters and the mining boom have resulted in considerable changes to these communities with more transient contractors and permanent employees taking up residence outside of these communities. This change, however, has not been as noticeable in the Hunter Valley region. The Hunter Valley, situated in the Sydney Basin has two main mining towns, Singleton and Muswellbrook. Of the 37 173 (Australian Bureau of Statistics, 2006) people that reside in the communities 13.8 to 16.5 per cent (Australian Bureau of Statistics, 2006) are employed directly by the mines. The Hunter Valley is a large tourist destination due to its many vineyards; this results in a diverse community where mining is not the sole means of employment. Similar to Central Queensland the mining boom has brought more people to the Hunter Valley region, although greater percentages have taken up residence in the communities. The views vary between the two regions on the coal mining industry, specifically on the socio-economic and environmental impacts that the industry may have on the surrounding communities.

Jan 1, 2008

By S K. Panda, M A. Van Ende, S Chatterjee

Tata Steel Netherlands (TSN) aims to reduce its CO2 emissions by 35–40 per cent by 2030 and become CO2 neutral by 2045. A first step to reach these targets is via the utilisation of an Electric Arc Furnace (EAF), which will run on a mixture of high proportion of Direct Reduced Iron (DRI) and scrap. For an EAF operation, optimisation of slag chemistry is important to achieve the right mix of basicity (for refining especially dephosphorisation), foaming, volume (rate) and refractory life. Slag composition and rate can vary widely depending on the process variables like charge mix, charge composition, feeding rate, oxygen lancing, external carbon injection/addition, fluxing and refractory erosion/corrosion. Moreover, it is important to note that the slag composition and rate are ‘transient’ parameters and change throughout the heat. This makes all the dependent phenomena and/or outcomes transient as well. To describe all these effects simultaneously and be able to realistically simulate the EAF operations, a validated dynamic process model is important in the absence of real plant data. In this study, a validated dynamic EAF process model based on the concept of Effective Equilibrium Reaction Zone (EERZ) has been utilised to analyse the impact of high DRI industrial scale EAF operations on the transient slag characteristics – including slag volume (rate), composition, phases, solid fraction and viscosity. Simultaneously, the model is able to predict the impact on steel and offgas characteristics. Case studies were performed with 70 per cent DRI:30 per cent scrap mix considering both low and high-grade DRI. Both melting and refining aspects of the process including continuous feeding, arcing program, carbon addition, fluxing and oxy-lancing were considered.

Jun 19, 2024

By A Mortazavi, M Akhmedya

Mining is recognised as being one of the most dangerous industries in the world due to the difficult working conditions. Working in such hazardous circumstances in an underground mine often results in a variety of accidents. The working conditions at Kazakhstan’s underground mines have deteriorated owing to a lack of a risk-reduction plan and methodology. This paper evaluates different underground mines in Kazakhstan and demonstrates the employed mining method and the observed failure modes. Risk assessment has long been recognised as a valuable technique for preventing accidents. In the underground mining sector, risk assessment tools play an important role in avoiding work-related accidents. However, geotechnical uncertainty is a significant source of severe incidents like stress-induced roof collapse, wedge failure, seismicity etc, which result in human and financial losses. A geotechnical risk assessment performed early in the mine design process might assist justify a different mine design component, such as different support systems for a dangerous location within the mine openings during mining. The goal of this research is to create a damage/failure database aiming at the development of a geomechanical risk assessment methodology. This work identifies a thematic structure linked to risk assessment and management for the examined Kazakhstan mining sector. As part of the developed database, the dominant modes of failure within the Kazakhstan underground mining conditions were investigated. The study will provide opportunities to establish future research objectives for Kazakhstan’s mining industry where there are significant gaps between state-of-the-art research and mining operations in practice.

Nov 29, 2022

By Huntington J. F, Green A. A

The quality of a photointerpreter's anno- tation of an image may be displayed by writing maps in which the pixels are shaded according to the number of times a pixel was seen to be on a feature. The map of grey tones is more valuable, if, for each grey level, a measure of quality is determined, which is the probability that a feature exists in a pixel of a given grey tone. From repeated annotations (at least four) of the same image by a single observer, it is possible to formulate a perception model which describes stochastic processes in the observer. From that model, it is possible to assign estimates of data quality for each observer to each grey tone. For two observers on the same scene, the 'mean' method of quantifying the grey levels is to assign a value equal to the mean of the ii,:lities for each of the two observers separately. For this example, the grey tones arr thus quantified at probability levels of 0.70, 0.80, 0.90 and 0.95.

Jan 1, 1977