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By Finch W, Dunne R

Understanding how liberated and unliberated minerals behave in comminution and classification circuits is of vital importance to ensure that maximum liberation occurs without unnecessary and costly overgrinding. This paper presents the results of a study carried out by the Julius Kruttschnitt Mineral Research Centre and Newcrest Mining of the liberation performance of Newcrest Mining's New Celebration grinding circuit. Using data from surveys of the circuit, together with QEM*SEM analyses of individual streams, a detailed picture of the liberation and classification of gold-associated pyrite is presented. In addition the relationship between the QEM*SEM analyses and results from laboratory leach tests are also discussed. Using the survey and QEM*SEM data, mathematical models were constructed of the performance of the ball mill and cyclones, and simulations carried out to investigate ways of improving the performance of the circuit. The results from the more promising scenarios are Reviewed.

Jan 1, 1993

By J Boshoff, D Reid

It has been recognised worldwide that the liquefaction risk of unconstrained tailings stacks or cyclone underflow embankments requires careful consideration. The stability of a tailings deposit where the perimeter embankments are made up of hydraulic fill is often governed by post-liquefaction stability.Cyclones are frequently used around the world to classify tailings into a coarse underflow for building a tailings impoundment wall and a finer fraction that is disposed of into the basin. The shear strength of the tailings that form the outer embankment of a tailings storage facility (TSF) and the location of the phreatic surface are the two most significant factors influencing the structural integrity of the facility. The coarse underflow is placed in such a way as to contain the overflow, which is finer, has low strength and is often poorly consolidated.A cyclone field trial was undertaken at a gold mine in Western Australia to assess the feasibility of using the cyclone deposition method to optimise and increase the capacity of an existing tailings cell. The aim of the cyclone trial was to collect information to demonstrate to the client and the regulators that cyclone deposition was a feasible option for raising TSF embankments. The cyclone trial provided an opportunity to assess the cyclone under field conditions and the quantity and quality of the underflow fraction produced on-site. A variety of methods were used to assess the flow liquefaction susceptibility of the tailings underflow sample produced during the cyclone field trial.The field trial, laboratory testing and analysis will be discussed in this paper.CITATION:Boshoff, J and Reid, D, 2015. The resistance of cyclone underflow material to flow liquefaction, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 151–156 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By B Y. Luan, Y Tian, W Zhou, X Lu, Q X. Cai

The unmanned driving technology in open pit coalmines is an important technology that relies on innovation to drive the development of the open pit coal mining industry in China’s transformation of growth drivers and industrial structure upgrading. It is an important path to solve the shortage of mine truck drivers in the future mining, an important way to improve the working environment of open pit mining personnel, and an important foundation for achieving flexible production capacity in open pit mining to cooperate with the coordinated development of new energy. The communication rules at intersections are key to ensuring the safety and efficiency of unmanned driving in open pit coalmines. This paper proposes a collaborative traffic strategy between unmanned trucks for the single bucket unmanned truck intermittent process system in open pit coalmines. Based on the gap theory, this paper analyses the conflict characteristics and establishes a coordinated traffic strategy for the common intersection and merging conflicts of unmanned truck trucks in open pit coalmines, A multi-agent system simulation platform was built to evaluate the coordinated traffic efficiency under different initial average gap sizes of vehicles, with intersection traffic density, vehicle speed, and gap changes as key indicators. The results show that under the simulation conditions of this article, when the initial average gap of vehicles reaches three (four) times or more of the safe distance, the coordinated traffic performance of intersection conflicts (merging conflicts) is better, and the traffic capacity of intersections is close to the traffic capacity without conflicts.

Sep 1, 2024

Completing its historical role the opera tion of copper blast furnace of the Saganoseki Smelter was terminated in 1970, but it left some interesting data on metal lumps formed at the furnace bottom. Analysis disclosed the lumps to be speiss containing 100 to 10,000 g/t of Au and Ag and stratified to iron speiss and copper speiss. Solidifying temperatures of iron speiss and copper speiss being approximately 1,090¦C and 800¦C respectively, copper speiss precipitated at the lower side. The distribution coefficient of Au and Ag between matte and speiss (g/t Au(Ag) in matte / g/t Au(Ag) in speiss) is in the range of 1 x 10 2 to 2 x 10 ' and 1 x 10 1 to 5 respectively. The higher Cu % is in speiss, the-more An and Ag are distributed into speiss. Except for a few data, these results comfotm well to the range of distribution equilibria of Au and Ag in matte and speiss systems by Gerlach and Others.

Jan 1, 1980

By LaBrooy SR

A number of gold processing plants in Western Australia have nickel in their ores, leading to significant levels of nickel on their loaded carbon. The presence of nickel during leaching, adsorption and elution'may have detrimental effects on cyanide consumption, carbon inventory requirements, stripping costs, electrowinning efficiencies and may contaminate the gold bullion.This paper discusses the competitive adsorption of gold and nickel cyanides onto activated carbon and investigates changes in solution parameters that may improve gold adsorption and/or inhibit nickel adsorotion.

Jan 1, 1997

By J Carswell, K McTyer

The Pajingo gold operation in Queensland is approximately 50 kilometres south of Charters Towers and 134km south-west of Townsville. The resource was discovered in 1983 and first open pit gold production began in 1986. The mine traditionally employed a bottom-up sequence – a combination of modified and traditional Avoca methods with run-of-mine waste backfill. This practice caused many high-grade crown pillars to be left in place, yet accessible. In recent years, these crown pillars have been extracted by injection grouting of rockfill. This process facilitated blind up-hole open stoping. To date, thirteen separate injection campaigns have been completed, of which ten were deemed successful. In general, the two key technical difficulties in this mining technique are: maintaining a consistent high-quality ground consolidation of the rock fill material; and controlling the drill and blast practices during stoping. Here, effective drill-and-blast control was found to be essential to achieve the dual aims of 100% extraction, and maximum sill pillar stability to minimise dilution. During stoping, the technical performance of the consolidated rock-fill was recorded; both to verify the design, and to identify operational improvements. The results showed that Pajingo has realised both reduced production down-time through use of early strength gain grout, and more rapid and thorough grout consolidation through changes to the emplacement method. The optimisation of consolidated rock fill has led to several quantifiable benefits to the mine, including: profitable extraction of previously sterilised crown pillars resulting in both increased ore reserves and production profile; improvements to the stability of grouted stope crowns, thereby reducing safety and production related; risks associated with open up-hole stopes; reduction in cost and time constraints, with respect to the grouting of loose fill; and reduction in grout curing time – from 14 days to 8 days – thereby minimising production down-time. This paper is a case study of the evolution and optimisation of the up-hole open stoping mining method at Pajingo. The challenges and successes are discussed in terms of their key mining outcomes. CITATION:McTyer, K and Carswell, J, 2018. Evolution of rock fill consolidation at Pajingo Gold Mine, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 66–77 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By Kadoya H, Kondo Y

The Harima works were established in 1964 and started operation in 1966. The initial capacity was 3500 t/month of zinc and 1500 t/month of lead. Until 1990 a lot of improvements had been made and the capacity had increased 6600 t/month of zinc and 2200 t/month of lead without enlarging the furnace size. During the ten weeks campaign shut-down at the end of 1990, many modifications were carried out including the enlargement of the furnace shaft area. By these changes, the capacity has gone up to 7500 t/month of zinc and 2500 t/month of lead. In the sinter plant, the amount of SO2 rich gas supplied to the acid plant was raised to 50 000 Nm3/h from 43 500 Nm3/h. An electrostatic precipitator was adopted instead of a venturi scrubber to clean the rich gas. Oxygen enrichment has been continuously operated since August 1991, because the furnace capacity is more than the rate of sinter production. Utilisation of the sinter plant is high being as much as 97 per cent and the sulphur burning rate has been increased. In 1990 the furnace was replaced except the hearth. The shaft area was enlarged to 19.4 m2 from 15.3 m2. The target blast was designed to be more than 36 000 Nm3/h. Tuyere layout was changed to prevent slag breakouts. Due to these modifications shaft condition has been very good. Automatic launder jacket cleaners were installed to increase the lead cooling efficiency. Many other improvements and developments were also made. Coke powder injection from the tuyeres has been successfully operated since April 1987.

Jan 1, 1993

Mine evaluation methodologies are well suited to evaluating many projects in capital-intensive industries other than mining. These industries include oil, gas, power generation, transport and infrastructure projects. A case study of an open cu

Jan 1, 1998

By T G. Vizcarra, B Wong

Optimisation projects are regularly undertaken without knowing the root cause of an issue. It is all well and good to trial a multitude of flotation reagents, change the operating characteristics of your flotation cells, or add more media into your ball mills, but time and again, root cause analysis traces issues back to the performance of hydrocyclones. In JKTech's experience, hydrocyclones are poorly operated and maintained (in both primary grinding and regrind circuits), exacerbating issues that many operations commonly experience.Recent case studies are presented where JKTech has been engaged to improve the process only to discover that the hydrocyclones were the main issue. At one operation it was found that the hydrocyclone feed density gauge was reading significantly lower to the actual density. Following re-calibration of the gauge, and with further improvement of cyclone operational and design parameters using JKSimMet, a significantly sharper efficiency curve was achieved. This resulted in improvements to downstream recoveries while alleviating pumping capacities that were previously constrained by fines and water caught up in recirculating loads.Several other case studies are presented which may seem to be relatively basic, but many basics seem to be getting lost in the day-to-day responsibilities of the modern plant metallurgist. Simple fixes to hydrocyclones can result in significant production increases, but more focus is needed in monitoring these to sustain the benefits.CITATION:Wong, B and Vizcarra, T G, 2018. What category cyclone is devastating your plant?, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 665–673 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

By D Felipe, G J. Harbort

In the past 40 years substantial changes have occurred in flotation machines. This has included increases in mechanical cell size to 630 m3 , significant changes to flotation column aeration design and widespread use of the Jameson cell and other pneumatic flotation cells. Over the corresponding period there has been increased used of machine characterisation measurements to benchmark and optimise flotation circuit performance. JKTech maintains a database of industrial flotation machine characterisation measurements. The database contains over 4000 entries and includes gas dispersion measurements, such as bubble size, gas hold-up and superficial gas velocity, cell dimensions and impeller tip speeds. Data comes from numerous operating sites and commodity groups, including gold, copper, molybdenum, nickel, palladium, lead-zinc, platinum, silica, phosphate, coal and iron ore. Flotation duties registered include flash flotation, preflotation, roughing, scavenging and cleaner circuits. Measurements have been conducted on a wide range of flotation machines from different manufacturers. This includes forced air machines, such as Outotec and Dorr Oliver, and self-aerated machines, such as Denver and Wemco. The database also includes substantial flotation column entries, such as the Microcel, Eriez/CMT Slamjet and Jameson cell. This paper describes the flotation machine characterisation database and discusses the variation between different types of industrial flotation machines, in operating production circuits.

Aug 24, 2022

By A Millar, B Wraith

Process plants are characterised by variability of performance over a wide range of time-scales; reflected in fluctuations in metal recovery, concentrate grade, plant throughput and reagent costs. In turn, these fluctuations impact financial metrics such as operating costs and revenue. The primary cause of plant variability is variation in the physical, lithological and mineralogical characteristics of the ore fed to the plant. The variability of the ore is driven by the intrinsic heterogeneity of the geology and mineralogy of the orebody, the mining method and mine production plan, the capacity to stockpile and blend, as well as the plant flow sheet and the level of plant automation. Whilst the impact of ore variability on process plants is universally recognised, it is rarely quantified in financial terms. Consequently, opportunities to reduce its impact are often overlooked due to the lack of a basis for a quantifiable cost-benefit analysis to justify improvement initiatives. This paper will present case studies using production data from the Renison tin concentrator and a zinc concentrator. These case studies demonstrate that as the standard deviation of plant head grade increases (as a proxy for ore variability), plant metal recovery subsequently reduces. The metal recovery is then converted into plant revenue losses, to quantify the economic impact of ore variability. The Renison case study demonstrated that whilst a very rare occurrence, revenue losses were as high as 34 per cent (relative to the baseline) when standard deviation was at its highest. The zinc concentrator case study demonstrated that revenue losses were as high as 6 per cent (relative to the baseline) when standard deviation was at its highest. Options are available for reducing and managing ore variability in the process plant. These options include changing mining practices so that the ore is fed to the plant with less variability, more advanced process plant control systems and the use of predictive geometallurgical models.

Aug 24, 2022

Traditional methods for the production of transition metals from their ores usually include the electric arc smelting of the ore or concentrate to produce a ferroalloy. This is subsequently refined to produce either a ferroalloy or to produce the metal or metallic carbide. Recent trends in the treatment of iron ores have seen the development of many processes for solid state carbothermic reduction followed by melting of the prereduced iron to produce steel and similar types of processes are under consideration for the production of ferroalloys. There are clear potential savings in energy and control of emissions from such processes. This paper discusses some research which is currently underway at La Trobe University into the solid state carbothermic reduction of chromium and tungsten ores to produce the metallic ferroalloy or the carbide for subsequent further processing. The kinetics of the carbothermic reduction of both chromite and scheelite were found to be dominated by gaseous CO rather than by direct carbon reduction. However the diffusion of carbon into the ore is certainly an important feature of the process. The production of tungsten carbide from the metal is the slow step in tungsten reduction. The development of phases during reduction were studied using a scanning electron microscope and an electron probe and knowledge of the phases produced allows analysis of the reduction process.

Jan 1, 1997

By Barro L

Very large reserves of gas are contained in coal. Because of the low permeability of the coal gas flow rates are very low. Fracturing of the coal can be achieved by use of the nitrogen - foam frac techniques described but the flow rates after fracturing are not sufficient to support economic development. Fracturing of the seams in the Bowen Basin was as predicted but in the Sydney Basin no trace of the fracture could be found when development proceeded past the fractured well. Testing of coal samples has provided some insight into parameters affecting desorption Rates.

Jan 1, 1982

By Lawless JV

Recent exploration for gold on the Pacific Rim has utilised similarities between active hydrothermal systems and epithermal gold deposits. The major control over formation of such deposits is the hydrology of the ore-depositing hydrothermal system, which varies depending upon its geologic setting.

Jan 1, 1987

By Johns AS

Comissioning of a new residue disposal tcluding upgraded classification for none backfill preparation, new variable speed pumps and a new residue dam took place in 1¦76. The system is described.

Jan 1, 1978

By J Nortier, J Dray

There is no single factor that determines the appropriate capacity for a mining project. It is driven by the size of the resource, the capacity of the market, the availability of capital, the availability of power, the availability of water, and a myriad of other considerations. There is also no single solution to the question of how big the project should be. However, to develop a project, the study team needs to select the configuration options that it regards as the best for the project. To be able to make this selection, the study team should consider the range of available options and do so at a level of detail that gives it confidence in the conclusion but does not lead to multiple detailed design exercises. Having considered the range of options, and with a clear definition of the project owner’s objectives and constraints, the work to be carried into feasibility studies can be focused appropriately. This paper discusses the process of completing strategic mine planning to identify project configuration options to assist in the selection of the processing plant throughput rate (Capacity Study) for a large greenfield open pit mine. The processes described in this paper allow for the basis of design to be set for subsequent studies that meets the objectives at a risk profile acceptable to the owner.

Jun 22, 2022

By P J. Handley

"Predicting how coal seams will be beneficiated through the coal handling processing plant (CHPP) has long been challenging within BHP Coal. Various coal seams from different areas are mined and stockpiled separately, often depending upon a deleterious coal quality parameter; high/low trace elements for example. These stockpiles are then fed in different ratios into the CHPP to produce the desired product/s. In understanding the washability characteristics of the feed source, mine geologists and process engineers work together to improve the beneficiation of different coal materials through the CHPP.For the majority of the BHP Coal deposits, the washability data is available for the coal seams across the deposits. However, no previous standardised modelling and prediction technique existed that could ensure the correct information was available for forecasting and refining CHPP processes. This paper will discuss the steps undertaken to implement a geometallurgical prediction tool that simplified and streamlined the washability modelling and yield estimation process. The value realised to the BHP Coal assets resulting from this process was: improved compliance to plan increased throughput increased CHPP recovery through improved efficiencies and increased revenues.CITATION:Handley, P J, 2017. Washability modelling and estimation techniques used to improve coal handling preparation plant beneficiation, in Proceedings Tenth International Mining Geology Conference 2017, pp 327–336 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 20, 2017

By C Hamilton

Stawell Gold Mines (SGM) is an underground mining operation located in Victoria, Australia. The mining method employed is long hole retreat stoping, utilising up and downholes and artificial concrete pillars. Stawell is currently mining the Golden Gift and Magdala orebodies.Access to the Magdala and Golden Gift deposits is via 6.0 m wide by 5.5 m high declines developed at a gradient of one in eight to one in seven from the surface to a depth of 1500 m, with a planned depth of 1650 m. From the declines, cross cutting drives are developed to intersect the orebodies. Orebodies in the Gift system are discrete lodes which are generally mined from a bottom up centre retreat to minimise geotechnical stresses.Ore development fronts are currently located between 1000 m and 1500 m below surface, with all ore being hauled to the surface using a fleet of 60 tonne underground trucks. With the use of conventional pyrotechnic long period (LP) delays, broken rock of combined ore and waste is thrown 10 m from the face and the materials hauled to the surface. The majority of the mullock from development is consumed in the underground as backfill.With the use of Orica Mining Services eDev™ Electronic Blasting System for Tunnelling, the waste is thrown up to 40 m from the face, while majority of the ore is left 5 - 10 m from the face, effectively segregating ore and waste. This enables significant recovery of gold values with minimal loss and significantly reduced dilution. By using this technique in ore drives with a 30:70 waste to ore ratio, SGM is able to haul 24 000 tonnes less mullock to the surface annually. Resue mining is applied to narrow vein headings and gives a 40 per cent grade increase at the faces as well as increasing the economic footprint of development. This will also contribute to an improved grade profile for the year from 3.98 - 4.16 g/t Au and allow extra capacity for ore haulage from stoping and for milling.This paper describes the application and the successful blast outcomes achieved using the eDev™ Electronic Blasting Systems for resue mining at SGM. Results to date, since commencement in March 2010, have been achieving significant benefits in terms of ore grade as confirmed by geologists grab sample grades. Face advance have also shown improvement with better breakage of perimeter holes giving improved face profile. These benefits are delivering increased productivity and safety performance when compared to other resue firing techniques.

Mar 21, 2011

By Mostyn G. R

An important problem in rock engineering is to control the properties of artificial rock. A compaction technique for casting artificial rock specimens with controlled properties is described, i.e. using a compression-testing machine to compress the mixture. Uniform density is necessary to achieve uniformity of properties of the specimens, and uniform density can be obtained by using the specific pressing method presented. Rebound and borax content are important to the technique and have been studied as well.

Jan 1, 1992

By Hayward N, Sutherland D, Wilkie G

A pilot plant study has been made of the liberation characteristics of a nickel ore under different milling conditions. A series of runs were made ranging from fully autogenous grinding to semi-autogenous grinding with a ball load of 8%. The mill products were sized and assayed then analysed by QEM4SEM. This enabled a full liberation analysis to be carried out to see whether the autogenous grinding leads to improved liberation by promoting selective breakage. Though it is frequently claimed that fully autogenous grinding yields superior liberation this could not be detected in the present study.

Jan 1, 1991