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By Wong PLM, Hsu YJ, Nguyen HH

The treatment of copper-gold ores has been plagued by several problems because of the interaction of copper minerals with the cyanide leach solution and the dissolved gold cyanide. Apart from the higher consumption of cyanide caused by the dissolution of various reactive copper minerals such as azurite, malachite, chalcocite, cuprite and bornite, native copper also causes the loss of gold due to its cementation reaction with the soluble gold cyanide. This interaction however is complicated by the strong dependence of various copper-cyanide species on the solution pH and free cyanide concentration.By understanding the effect of various operating conditions (pH and cyanide concentration), several treatment processes could be implemented to minimise the copper-gold interaction and to separate copper from mixed copper-gold cyanide solutions.

Jan 1, 1997

By T P. Tafirenyika, K C. Corin, C T. O’Connor

There is a growing demand for copper driven by its applications in renewable energy and electric vehicles. Sulfide ores are an important source of copper. Flotation is a critical front-end process used to remove gangue minerals and concentrate the copper minerals. The electrochemical activity of sulfide minerals contributes to their overall activity in the flotation pulp. The mineral rest potential dictates how collectors interact with the mineral surface, and hence ultimately on the flotation response. Dissolved oxygen, (DO), pH, redox potential (Eh) and water composition and ionic strength are also significant in controlling flotation performance. The aim of this investigation was to determine the influence of the electrochemical environment both during milling and flotation on the flotation behaviour of bornite and chalcocite. For this investigation, the interactions of collector with bornite and chalcocite were studied using synthetic plant water (SPW1) and deionised water (DIW) at 5 different pH levels. Sodium isobutyl xanthate (SIBX) was used both in microflotation, collector adsorption and zeta potential tests.

Aug 24, 2022

By N Madani, S Abulkhair, N Morales

Conventional geostatistical algorithms cannot reproduce bivariate complexities such as inequality constraint, nonlinearity and heteroscedasticity. Poor reproduction of these features may decrease the accuracy and reliability of mine planning results. For example, it is not unusual to have an inequality constraint between primary and disturbing elements in a metalliferous deposit. Implementation of traditional methodologies for such complex data sets can lead to the incorrect reproduction of a bivariate relationship, which will affect the validity of NPV results. In this paper, an iron data set containing iron and silica grades with an inequality constraint between variables is introduced as a case study. This study proposes an algorithm based on a hierarchical sequential Gaussian cosimulation integrated with inverse transform sampling. The proposed methodology considers the linear inequation between two variables in the hierarchical cosimulation process to reproduce an inequality constraint. As a comparison, conventional sequential Gaussian cosimulation is also applied to the same data set to demonstrate the difference in bivariate relationships from both models. Unlike the proposed algorithm, the conventional cosimulation cannot reproduce an inequality constraint and slightly overestimates silica grades. The modelled realisations are then used to assess the uncertainty of a plan and generate a stochastic strategy that adapts the destination of the blocks depending on the scenario. Two-stage stochastic long-term production scheduling takes extraction decisions using average information (ie e-type model) and ore/waste destinations based on geostatistical realisations. As a result, the proposed strategy is closer to the upper bound, highest possible NPV for each realisation, than to the lower bound, deterministic strategy that does not manage the risk of sending extracted material to wrong destinations. Furthermore, Comparing production schedules resulting from proposed and conventional geostatistical methodologies shows the importance of inequality constraint reproduction and more accurate long-term mine planning.

Nov 8, 2021

With commodities suffering dramatically low real prices, mining business margins are under intense scrutiny. Unfortunately, management systems developed early this century for manufacturing are driving counterproductive behaviours that choke productivity. The paper and presentation will explain this and present a proven methodology for increasing productivity. This will be supported by operational examples from Australian and American mining management to demonstrate the importance of modern business performance measurement and analysis systems. It will explain the importance of management systems in driving organisational change to sustain superior productivity and margins. The paper will explain why many executives and managers confuse production (a measure of volume) with productivity (which measures efficiency and effectiveness). It will explain how this and other counterproductive managerial and operator behaviours and attitudes are driven by traditional business management systems exacerbated by managerial and consulting fads. The paper will begin with the simple principle that to improve results one needs to first improve the process producing the result û and will show how this is often violated. Improving productivity then boils down to:accurately identifying opportunities using sound, modern measurement, analysis and reporting systems; methodically improving operating and commercial processes, and changing peopleÆs behaviours and attitudes to sustain changes in practices. The paper will include fundamentals of applying sound measurement and analysis to:processes directly, eg cycle time charts and their impact in cyclical (non-continuous) operations commonly used in rock breakage; drivers of productivity; and process results themselves since correct analysis identifies opportunities accurately. The paper will cover the importance of practical leadership and the need to follow a simple, solid plan for changing systems that drive behaviour. Overall, it will highlight use of modern performance Measurement, Analysis and Reporting systems to drive behaviours and improve margins - without capital investment û and make executive and managerial work easier and more effective.

Jan 1, 1999

By Lilly PA, Kavetsky AP

An empirical, kinematic model is developed which calculates the trajectory of individual blocks of rock in a blast, their point of impact in the muckpile and the final shape of the muckpile. The method is based on the determination of initial block velocity and requires input on stemming length, bench height, subdrill, burden, spacing, energy of explosive per unit length of blasthole, energy attenuation rate and resistance to movement. The model, which will form part of a comprehensive blast simulation package, has application in open cut mining in predicting muckpile geometry and the movement of grade blocks during blasting, which in turn impact on shovel productivity and grade control.

Jan 1, 1986

A model of dense medium cyclones is developed based on balancing the terminal velocities of the discrete particles due to the centrifugal force against a random turbulent eddy velocity. An expression of the form P - or Q _ 1 100 e."A where P is the partition number., is a function of cyclone efficiency, particle size and density differential between the particle and medium, and is the slurry spilt, is developed and may be used for regressing plant partition data. The above model provides an understanding of peculiarities of the partition curve such as asymmetrical tails, elevation of the cutpoint and elevation of the d50 with increasingly fine feed. The effect of feed variables such as particle size, medium viscosity and changes in spigot or vortex finder diameter is shown. A means of convoluting the partition curve with various feed washabilities is discussed together with how the above may be used to evaluate plant performance for a variety of feeds.

Jan 1, 1987

A study of the bacterial oxidation of naturally occurring high-purity sulphide minerals (FeS2, Fel_xS, CuFeS2, Cu2S) has been conducted using a mesophilic strain of T. 6ejtAooLcdcth4. As well as metal analyses and solution pH, partitioning of sulphide sulphur into elemental sulphur and sulphate ion has been monitored. Partially oxidised sulphide substrates have been characterised at regular time intervals by X-ray diffraction methods and extra-cellular organic compounds reporting into leach solution have been identified by'thin layer chromatography. The results indicate that the S¦/SO4 2 partitioning of the sulphide substrates is independent of cell inoculum size and initial pulp density and varies with solution pH, Eh, leaching time and mineralogical properties of the individual sulphide minerals. The signifi- cance of results for applications in selective flotation, coal desulphurisation and agglomera- tion has been outlined.

Jan 1, 1984

In 1975, following a programme of solution characterization and small scale laboratory test work, a pilot plant was constructed to treat waste liquors from the Risdon works. The plant was designed basically to neutralize liquor to a desired pH, and to flocculate, thicken and then filter the resultant pulps. The primary objective was to purify waste liquors to stand- ards set by Tasmanian environmental regulations and at the same time to provide design data for construction of a full scale treatment facility. Waste liquors were divided into two groups, those from the Zinc Plant, and those from the Acid and Superphosphate Plants, and were treated independently. To satisfactorily purify Zinc Plant waste liquors the following reaction sequence was required: 1. Neutralization to pH 10.5 (with aeration for Mn removal). 2. Further reaction of neutralized pulp with Na2S at an addition rate of typically 5 mg of S2-/litre of liquor treated to remove Cd.

Jan 1, 1977

Since the early 1990s it has been evident that electricity demand has outstripped investment in generation and transmission. At the same time, concerns were being expressed about the risks associated with the run down of the Maui gas field. It is axiomatic that the necessary investments firstly require a stable and supportive regulatory and fiscal environment, and secondly that such investments have long lead times. A unwillingness by successive Governments to fund the necessary infrastructure, however, lead to the profound restructuring of the electricity with the ultimate objective of transferring the investment risk from Government to the private sector. Successive power crises since 1992 result from a failure to put in place a regulatory framework necessary to provide the environment to allow the private sector to make the needed investments within the necessary timeframe. The electricity sector has now stabilised to the extent that the regulatory risks associated with generation investment have been reduced. This does not mean that risk has been eliminated, however, and both economic and environmental issues will continue to constrain investment in some power proposals particularly those in the South Island and especially any South Island coal or gas thermal proposal. This is firstly because of several very simple economic issues:  1. while the South Island may have significant coal resources it lacks a significant electricity market; 2. except for a six to ten week period in a dry year, low cost hydro will price any large-scale South Island thermal out of the market which will restrict any large scale thermal station to a dry year and/or peaking load; 3. except for a six to ten week period in a dry year, export capacity on the HVDC link to the North Island is constrained to around 964 MWe (and 482 MWe from North to South in dry years); and 4. construction of any new thermal plant in the northern half of the North Island will price any South Island thermal station out of the market. There are also significant environmental issues associated with the establishment of a large scale thermally based power station in the South Island. Because the South Island lacks any large scale economically proven gas reserves, the environmental constraints considered are those associated with coal production. A coal mine dedicated to power generation will have significant on-site impacts associated, in particular those associated with disposal of opencast overburden and visual impacts. These will, however, be partially offset by the relative remoteness of such sites to population centres. What cannot be offset, however, is the off-site impacts, in particular, CO2, SOx and NOx emissions, water disposal and acid mine drainage.

Jan 1, 2003

By C Sylvestre

For the last 50 years, traditional safety management has improved safety performance by: • Fixing the environment (eliminating the hazard). • Improving the system (more/less rules, procedures etc). • Making safety more conscious (more/better interactions about the importance of safety). Although these approaches certainly have merit, and may be part of an overall solution, they are not enough to prevent many modern-day incidents. Today, these three approaches are used more than before, and are used better than ever before. Yet, workplace fatalities in Australia have stagnated from 2013 to 2019, as have the number of incidents, even serious ones. In the USA, workplace fatalities have increased by 15 per cent in the same period.

May 5, 2022

By R Hao

Uncertainties in large open pit geotechnical modelling has been a major concern for slope stability analysis. The level of confidence in the in-put assumptions, such as structural and rock mass model, dictates the modelling results to some extent. This article is to detail a case study of Kalgoorlie Consolidated Gold Mines (KCGM) regarding a predicted inter-ramp failure on an as-built pit walls by a 3D numerical modelling. Significant concerns were raised across site and multiple preventive plans were considered. After intense data collection work, it was confirmed that the risk of failure had been overestimated. The case study has improved the understanding of geotechnical data in-put and has enhanced the process of creating and updating geotechnical structural models at KCGM.

Jun 22, 2022

The report by Baker (1958, p. 27) of krennerite in contact with gold in a specimen from the 2500 ft level, Phantom South lode, Great Boulder mine, Kalgoorlie, led the writer to look into this further, since Cabri (1965) reported that the assemblage krennerite-gold was unstable between 238° and 356° C, and possibly down to room temperature.Dr. G. Baker very generously provided the writer with two chips from the same rock specimen (No. 14 as labelled from the mine) in which the krennerite gold assemblage was reported to occur. These were examined by polished section and x-ray diffraction techniques and returned to the classified collection of the Mineragraphic Investigations Section of CSIRO.One specimen, showing visible gold, was examined optically with a binocular microscope and telluride material was twice removed from contact with the gold for x-ray diffraction. This material proved to be petzite and so amends a statement by Baker (1958, p. 39) that no petzite was found in the Phantom lodes.The second chip was polished, and microscopic...

Jan 1, 1967

By R Young

Independent Project Analysis (IPA) is in the business of benchmarking the performance of capital projects on behalf of owner companies in the processing and extractive industries. IPA assesses between 500 and 800 projects each year. The projects are conducted globally and range in size from about $1 million to over $30 billion. Using the data, we are able to benchmark the performance of Australian projects against the rest of the world. This presentation focuses on the performance of large (greater than $100 million) projects that involve chemical or thermal processing.We regularly hear calls for more processing to be conducted in Australia but on the other hand industry leaders are concerned about the poor success rate of solids processing projects in Australia. Data gathered by IPA indicates that there is good reason for the concern. Out of a sample of 31 large processing projects conducted in Australia, 23, or 74 percent, were classed as failures. This performance is significantly worse than for similar projects in other parts of the world. The presentation analyses why the performance is worse and demonstrates that many of the reasons behind the failures were manageable by the project team. Furthermore, members of the project teams on at least half the failed projects knew that the projects were on a path to failure before the project was authorised but could not be heard.The presentation discusses how large projects that involve process design and, in many cases, new technology, need to be set up for success. *This is an abstract only. No paper was prepared for this abstract.*

Aug 8, 2011

By Harvey T, Kizil M, Bride J

Hydrogen sulphide (H2S) as a seam gas has occurred in several locations in the German Creek seam at Southern Colliery. This paper overviews the techniques developed to quantify the H2S content of the seam, overviews research into controlling and reducing H2S emissions from the seam, and details the procedures used to mine through the HZS zone in 702 longwall panel. Learning points from research and mining experience are reviewed for application in the next longwall block.

Jan 1, 1998

By S Moradi

The thickener overflow of zinc concentrate, obtained from flotation process in the Angouran plant located in Iran, contains a large quantity of slimes which were transferred to the tailing ponds. These slimes have caused problems of storing and environmental aspects in the Angouran area. The objective of this research is to describe the extraction of zinc from these slimes by leaching method using sulfuric acid in pilot plant scale.Chemical analyses showed that these tailing materials contain 35 per cent of zinc. By XRD analysis, smithsonite is identified as the major constituent. Calcite, dolomite, and cerussite are found as carbonate minerals. A minimal amount of Zn occurs as hemimorphite. Quartz, kaolinite, clinochlore and muscovite are other silicate minerals in the slimes.In the optimal conditions, ie acid leach at pH of 1, temperature of 55¦C, reaction time of 120 minutes and solid-liquid ratio of 1:3 and neutralisation with Ca(OH)2 at pH = 4.5, temperature = 70¦C, time = 90 minutes, the total recovery of zinc obtained was 95 per cent.

Jan 1, 2004

At some time in the mining life of an open cut coal deposit, consideration is usually given to determine the point at which underground mining becomes an economic proposition or even necessary. This can occur anywhere from the pre-feasibility project stage to decades after commencement of mining. Options which can be considered include the extension of the life of the open cut by use of larger equipment, the utilisation of highwall mining techniques and the introduction of low capital start-up or full underground development. The primary focus is always the minimisation of the total unit cost (including capital )of clean product. The transition point at which an undergound mining operation becomes more economic than an open cut operation is not a simple evaluation and depends on many factors, particularly on the nature of the deposit itself. The main general determining factors of the transition point are related to the three factors of mining resource, the mining method that can be used and mining cost issues. Mining resource issues include geography, geotechnics, strip ratio, geology and the size of the deposit. Mining method issues include highwall mining, extending the life of an open cut, the environment, available roof support technology, product yields and the availability of appropriate workforces. The mining cost factors discussed include capital and operating costs and the impact of productivity and management. All these factors impact to a varying extent on the transition point.

Jan 1, 1997

By Barber C, Buselli G

Detailed monitoring of point sources of groundwater pollution is expensive due to the high cost of drilling monitoring boreholes. Whether groundwater pollution is due to mining, industrial or domestic waste disposal, a universal difficulty when monitoring groundwater contamination is the placement of boreholes to adequately define the extent of the pollution plume. This paper reports groundwater 'resistivity variations determined from transient electromagnetic soundings at a domestic waste disposal site north of Perth in Western Australia. Together with available hydrogeological and water quality data, the geophysics provides a broad "plume scale" picture of groundwater contamination. A simple three dimensional model of plume development, which takes account of the dimensions of the wastes, has also been developed and shows good agreement with the spread of contamination indicated by the geophysics for relatively small values of the dispersivities. Better estimates of these parameters are still required. The work indicates that a combination of geophysics and modelling with ground-truth data from groundwater quality monitoring of boreholes is required to avoid difficulties in interpretation of data and to better define the extent and migration of pollution in Groundwater.

Jan 1, 1988

By T J. McGavin

This paper examines the fire life systems implemented in two existing tunnels and discusses whether the standards used were appropriate. It focuses on the Terrace Tunnel as this upgrade and refurbishment is complete.The New Zealand Transport Agency (NZTA) manages six tunnels on the State Highway network with two of these built in the last seven years. The Terrace Tunnel, opened in 1978, was refurbished with modern fire life safety systems in 2010–2012. An interim upgrade of the Mt Victoria Tunnel, opened in 1931, was also carried out at this time.In present times, few existing tunnels have undergone significant upgrades and refurbishments. The Terrace Tunnel required: new power supplies, control buildings, lighting, wall panels and jet fans, a deluge system, emergency exit lights and way-finding lights, a public address (PA) system, a radio rebroadcast system, lane control sign (LCS) and variable message sign (VMS), an over-height detection system (OHD) and a new tunnel management system.In the absence of suitable guidelines, various standards were used to carry out the refurbishment. The Austroad Guide to Road Tunnels and AS4825 Tunnel Fire Safety, although designed for new tunnels and not specifically intended for existing tunnels, provided a framework. A multi-criteria assessment of risk (MCAT) was carried out to determine the systems to be provided.The Terrace Tunnel has perhaps set a benchmark for refurbishing existing tunnels as few projects of this type have been completed recently. This paper examines the process and the outcomes.CITATION:McGavin, T J, 2014. The refurbishment of the Terrace and Mt Victoria Tunnels, Wellington, New Zealand, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 87–94 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By T J. Callaghan

The Avebury nickel mine in Western Tasmania is a disseminated nickel sulfide deposit hosted in intensely metasomatised Cambrian ultramafic resulting from later Devonian granite related hydrothermal activity.Variable metasomatism of the ultramafic has formed two distinct gangue mineral assemblages. Less metasomatised ultramafic is comprised of fine grained black antigorite with minor disseminated chromite, magnetite and pentlandite. Intensely metasomatised ultramafic is altered to a pale grey or green, coarsely crystalline tremolite/actinolite and diopside assemblage with minor magnetite, chromite and sulfides. Both gangue mineral assemblages are frequently intermixed in ore grade mineralisation.The bimodal gangue of either serpentinite or metasomatised ultramafic presents challenges to drilling, mining, resource estimation and mineral processing as they possess very different physical properties. Mineralised serpentinite has a mean bulk density of 2.8 g/cc and the ultramafic skarn a mean bulk density of 3.2 g/cc. Physically, the ultramafic skarn is hard to break percussively creating difficulties in the crushing circuit and reducing mine development rates. However, it is non-abrasive and grinds readily, resulting in increased diamond drilling rates and increased mill throughput. Conversely the serpentinite gangue is softer and breaks easily resulting in accelerated development rates and crushing circuit throughput. However, its fibrous nature reduces grinding efficiency, increasing bond work indices and reducing diamond drilling rates.Predicting the ratio of serpentinised to metasomatised ultramafic is possible through use of the resource blockmodel, assisting mine scheduling, predicting mill throughput rates, energy consumption and grade control drilling rates.CITATION:Callaghan, T J, 2017. Challenges of bi-modal gangue mineralogy in mining geology, in Proceedings Tenth International Mining Geology Conference 2017, pp 23–26 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017

Basic Oxygen Steelmaking (B.O.S.) commenced in Australia in December, 1962. Two 200-ton furnaces were installed initially at Newcastle with a 50-ton furnace coupled to a continuous casting machine added in 1967. In 1965, two 100-ton furnaces were installed at Whyalla plant and two 225-ton furnaces are nearing com- pletion at Port Kembla to commence oper- ations in 1972. Plant layouts in each centre differ due to changing circumstance and increasing knowledge of the B.O.S. process since 1962. Raw materials are a most important factor for good operation of the process. Most materials come from within Australia but some are imported. General operating practices are similar in each plant, although treatment of fume at Port Kembla will be by the OG (Oxygen Converter Gas Recovery) Process as against electrostatic precipitators in Newcastle and Whyalla. Special alloy steels as well as plain carbon steels can be made by the B.O.S. process. Production potential of the process in Australia has yet to be fully utilised with 45 per cent of steel production coming from B.O.S. In 1971.

Jan 1, 1972