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By K Williams, W Chen, J Miller

The flow function of an iron ore material governs its flowability characteristics in material handling chains within the resource industry. A uniaxial compression test is able to obtain a flow function more rapidly comparing to the Jenike direct shear test; nevertheless, the results often exhibit lower rankings using the former method. This study aims to investigate the fundamental stress states within the test specimen that lead to this phenomenon, and to introduce a new uniform density specimen preparation method for a uniaxial compression test, in order to achieve comparative flow functions as for a Jenike direct shear test. The minimisation of the wall friction effect and achievement of the critical state when preparing a uniaxial specimen are explicitly discussed. Experimental investigations on flow functions of a suite of Australian iron ore samples were conducted using both the uniform density uniaxial compression test and the Jenike direct shear test. Results from both methods were found to be comparable, providing the specimen exhibits cohesive flow behaviours. The outcome of this research enabled development of a rapid and reliable flow function testing method for cohesive iron ore materials.CITATION:Chen, W, Williams, K, Roberts, A and Miller, J, 2017. Rapid and reliable flow property testing – a modified uniaxial approach, in Proceedings Iron Ore 2017, pp 149–154 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By M Amanzadeh, S M. Aminossadati, B M. Masum, M S. Kizil, C R. Leonardi

Gas sensing systems are becoming more important in many industries such as oil, gas and mining operations. Particularly in underground coalmines, accurate and reliable monitoring of toxic and combustible gases such as methane, nitrogen dioxide, carbon monoxide and hydrogen sulfide is essential. Available conventional electrochemical sensors for gas measurements in underground coalmines suffer from shortcomings such as cross-sensitivity response, limited lifetime, high calibration cost, maintenance cost and safety. Recent studies have found that fibre optic-based gas sensors have potential to eliminate these issues. These sensors can also be used for long distance and distributed sensing of various gases, both of which are important for underground gas monitoring. The aim of this paper is to review the present underground mining gas monitoring systems and review the new generation of fibre optic-based sensing systems for use in underground coalmines.CITATION:Masum, B M, Aminossadati, S M, Leonardi, C R, Kizil, M S and Amanzadeh, M, 2017. New generation of gas sensors for underground coal mining applications, in Proceedings Australian Mine Vent Conference 2017, pp 189–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

By R Shaw, M Hidding

The design of primary sample cutters for high-capacity conveyors is critical to achieving a correct sample, both in collecting the sample and ensuring smooth sample discharge flow. Modelling usually occurs at the design stage and requires extensive experience to achieve the correct result. However, it is difficult to confirm the effectiveness of the cutter design until after installation. Even with high-speed video, confirmation of complete sample capture is difficult, especially if the material characteristics change over time. Recent investigation using discrete element method (DEM) simulation to model the flow of the ore into the cutter and observe how it interacts with the cutter has revealed some interesting design requirements not observed in the past. By including DEM modelling, the correct design and optimisation of the cutter can be more accurately determined prior to commissioning.CITATION:Hidding, M and Shaw, R, 2017. Modelling ore flow in the design of high-capacity sample cutters, in Proceedings Eighth World Conference on Sampling and Blending , pp 145–150 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

Pilot-Plant Testing of Ammoniacal-Cyanidation for Gold Recovery from Copper Gold-Bearing Ore The results of pilot-plant tested ammoniacal-cyanidation of gold recovery from copper gold-bearing ore are presented in this paper. This ore is from a deposit of Russian Federation with gold and copper grade 9.5 g/t and 0.4 per cent, respectively. Copper is largely present as malachite and azurite. The presence of chalcopyrite and bornite is also observed. In order to recover gold, gravity is recommended. Two options of ammoniacal-cyanidation using leaching of gravity tails, CIP and filtration, were tested. It was found that ammoniacal-cyanidation using filtration of leaching tailings and recycled solutions is the most optimal option. The proposed flow sheet provides for 89.7 per cent gold recovery from gravity tailings at the consumption of NaCN 0.9 kg/t and (NH4)2CO3 7.5 - 9 kg/t. Compared to conventional cyanidation, this technology decreases the consumption of sodium cyanide from 4 up to 0.9 kg/t at the same gold recovery. It can be recommended for the treatment of copper gold-bearing ores with the similar composition.

Sep 13, 2010

Modelling and Simulation to Design a Flotation Circuit for Gold Concentration

Sep 13, 2010

By G R. Howard, G Back

Management of information systems for data collection is essential to maintain data integrity and continuity, and manage loss control on a large world-class mine such as Telfer Gold Mine. This paper aims to describe the individual systems and protocols of geological data capture at Telfer, then focus on Quality Assurance Quality Control data as an example of loss control in practice. Loss control systems are required to provide capacity, flexibility, structure and management tools to enhance data interrogation. The data that have been collected can then provide geological, financial, environmental, and contractual information to optimise management of business best practice. Telfer Gold Mine is a wholly owned and operated subsidiary of Newcrest Mining Limited. The mine is located in a remote area of NW Western Australia, and has been operating for 20 years. Geological data have been collected at Telfer since 1973. The data include drilling, assay, geological, survey, structural and geophysical data. Data management has evolved through many systems with data stored on many different hardware and software platforms. Commencing in 1995, collation, standardisation and validation of the historic data was completed. This has resulted in the first Access based drill hole database incorporating all available drilling data. This drill hole database, now hosted in SQL Server, is the hub for all geology related data management systems. The Telfer Gold Mine Geology Department has developed a series of inter-related database systems in order to manage the core geology business issues. Databases relating to drill hole planning, drill contract management, geological logging, accounting (standard costing, forecasting, invoice reconciliation), quality control (QAQC), and environment rehabilitation have all been developed to manage loss control. Management effort to provide adequate data systems and protocols has driven the system from concept to utilisation. The improved productivity, data integrity and data analysis capabilities provided by the new database systems at Telfer have allowed for greater confidence in decision making. Systems such as the drill hole and QAQC databases, when utilised in the proper manner provide up-to-date data analysis for resource audits and contract negotiations. The loss control systems are essential to maintain confidence in data integrity and hence directly effect the future of mining at Telfer.

Jan 1, 2000

By K Niyomjinda, B Etschmann

Chatree Gold Mine is currently the only modern day gold mine operating in Thailand, and is situated approximately equidistant from Chiang Mai in the north and Bangkok in the south. Environmental guidelines set by the Thai authorities require Chatree Gold Mine to achieve a Total Cyanide level of 20 ppm or less in the process plant discharge slurry stream prior to release into the tailings storage facility. This paper describes both the initial difficulties faced in achieving compliance on this limit utilising the conventional INCO SO2/Air cyanide destruction system and the subsequent process improvements initiated to both the leaching process and the standard INCO process to achieve the current compliance levels of approximately 99/100 shifts. Improvements were focussed on the dual aspects of reducing the formation of WAD cyanide and ferrocyanide species in the leaching circuit coupled with process changes to improve removal of the ferrocyanide species from solution during the cyanide reduction stage.

Jan 1, 2004

By M Humphreys

Multi-episodic mineralisation is often characterised by different spatial trends exhibited by different generations of the mineralisation. The structural complexity of mineralisation together with the heterogeneous nature of the mineralised zones prevents unambiguous application of the conventional deterministic methodology for 3D constraining of the mineralised domains (ie conventional wireframing is ambiguous).A different approach, discussed in the present paper, includes a probabilistic definition of the domains encompassing one statistical population of the data. The domains are defined geostatistically using the indicator probability model. An indicator threshold is chosen for the definition of the high and low-grade domains. The spatial distribution of this indicator is then modelled by a variogram. The probability of exceeding the given grade threshold is than estimated by ordinary kriging for each modelled block. Blocks are then grouped according to their probability of exceeding the threshold and a continuous closed volume (domain) created from this likely patchy grouping using an appropriate structural model to fill the gaps). Methodology for the geostatistically assisted domaining is discussed in the paper. It is suggested that this technique represents an additional tool facilitating a structural interpretation of the mineralised zones.After the geostatistical domaining of the lode has been completed the grade within each of the domains is modelled using Uniform Conditioning method. Application of Uniform Conditioning for modeling the grade distribution has a significant advantage over linear methods (such as inverse distance or kriging) because Uniform conditioning enables estimation of local recoverable resources at different selective mining unit sizes that can be substantially smaller than the drilling density and are unable to be estimated directly.

Jan 1, 2002

Integrated Utilisation of Desulfurisation and Skimming Slag

Sep 13, 2010

By Tuck M. A

The increasing depth, mechanisation and distance of working areas from surface connections places an ever greater contaminant burden on ventilation airflows. Some British Coal mines are already experiencing significant problems in providing adequate climatic conditions in the working areas and have had to introduce air conditioning. Previous work has shown that in mines of low to moderate virgin strata temperature the application of controlled district recirculation could serve to improve climatic conditions at the working area.

Jan 1, 1988

Study on Rational Process Flow Sheet for Beneficiating Low-Grade Cu, Mo, Bi, S, W Polymetallic Ore

Sep 13, 2010

By C A. Locke, A B. Christie, J Cassidy, J L. Mauk

New and existing gravity and aeromagnetic data are used to determine the structure of the Waihi region and to investigate any relationship between structure, hydrothermal alteration and epithermal mineralisation. The 24 mGal, 10 km diameter, negative Bouguer gravity anomaly which occurs south of Waihi has been modelled as a I.5 km deep asymmetrical basin. This basin, the Waihi Depression, is interpreted to be infilled with low-density volcanic rocks of the Uretara Formation and Whitianga Group, overlying older andesites of the Waipupu Formation. To the north and west, the margins of the depression are defined by the Waihi and Mangakino Faults, which have been modelled with dips of 45 - 60¦ to the south and west respectively. The southern and eastern boundaries of the Waihi Depression are defined by smooth, shallow dipping (15 - 20¦) boundaries. The Waihi Depression is interpreted as a fault-angle depression, resulting from southeast extension in the early Pliocene. The Waihi Fault is modelled as an approximately E-W feature, located to the south of Waihi. Small 2 - 4 mGal positive Bouguer gravity anomalies occur north and west of the margins of the depression, and correlate with known areas of hydrothermal alteration and areas of low magnetic gradient.

Jan 1, 2003

Copper Recovery from Printed Circuit Board by Carbonisation

Sep 13, 2010

Tonnage and grade are the principal reported components of mineral resource estimates but tonnage is a derivative of two more fundamental estimates; volume and bulk density. Typically, most of the effort in a resource estimation study is directed towards grade and volume, yet poor application of bulk density data to resource models can result in significant biases. The impact on tonnage estimates is easily recognised but poor density estimates may also introduce subtle biases into the grade estimates. Methods for measuring bulk density have been discussed previously. This paper focuses on the manipulation of bulk density data and the extension of bulk density from essentially point measurements to block estimates within resource models. Bulk density is a continuous, geologically controlled, spatial variable and should be treated as such. Issues such as combining data from multiple sources, sample support and the interdependence of bulk density and grade estimates must be resolved. The statistical and geostatistical techniques used for grade estimation are, under the right circumstances, equally applicable to bulk density. The importance of bulk density needs to be recognised. With robust raw data and correct estimation procedures, better estimates of bulk density can be obtained and both local and global tonnage and grade estimates can be improved.

Jan 1, 2000

Study on Basic Theory of the Grain Settlement in Fluidised Bed This paper takes thick goal grains (less than 1.5 cm) as research object. According to different densities and particle sizes, thick goal grains are divided into 20 kinds of narrow density and narrow size level average grains. Free settling and hindered settling tests are respectively carried out in ?100 fluidised bed thick goal separators. Hindered settlement includes hindered settling velocity test and measurements of suspension density. Results show follows. (1) Fluid state in separator belongs to transition region. Alien's law is the appropriate formula of thick coal particles free settlement terminal velocity. (2) The main factors affecting hindered settling velocity are the number of solid particles in medium and the structure feature of the particle group. The bigger volume fractions of solids ? is, the smaller decreasing velocity coefficient of particle hindered settlement ¯ becomes. In the organism from bottom to top, density of suspended particles in fluidised bed gradually decreases, but near the top of the suspended particles, the density increased slightly. With increase of density and size, suspension density reducing extent increases from bottom to top of separators.

Sep 13, 2010

Technical Challenges in the Flotation of Molybdenite from Porphyry Copper Ores

Sep 13, 2010

Adhesion of Escherichia coli onto Oxide Minerals - Extended DLVO Theory and Flotation Behaviour

Sep 13, 2010

Electronic noses are being used in the processing industries and in fields such as environmental and occupational hygiene to detect a wide variety of problems from contaminated foods to toxic chemicals in soils. Recently, research has been conducted into the use of these devices for detecting spontaneous combustion in mines with the aim of producing a method for early detection of a developing heating. Gas samples were collected from both SimtarsÆ 16 m3 large-scale spontaneous combustion reactor and the University of QueenslandÆs two-metre column. The samples were analysed using an electronic nose. GCMS and HPLC were used to identify some of the components present. A number of issues both from a practical mine situation and a scientific standpoint have been identified that need to be addressed before these devices can be used to detect a developing heating. Aluminised bags routinely used in the mining industry to collect gas samples for analysis of the permanent gases are not suitable for use with electronic nose devices as they have a æfingerprintÆ from the polymer lining that interferes with the coal heating fingerprint. Tedlar bags used for environmental gas sampling are also unsuitable due to their fingerprint. Gas samples can be collected in glass gas bulbs with aluminium seals and successfully analysed. However the aluminium foil used to seal the bulbs is a restricted item in underground mines. It was also found that the volatile organic fingerprint of the coal heating was extremely weak at temperatures below 130¦C. Before a useful application can be developed, further investigation into the chemical species present in the off-gases from Australian coals is required.

Jan 1, 2005

Optimisation of the Performance of Flotation Circuits Using a Genetic Algorithm Oriented by Process-Based Rules

Sep 13, 2010

By M P. Cipold, J F. Bachmann, C C. Bachmann, J Ha

Knowledge of fuel qualities is of ultimate importance for the efficiency of chemical plants or power stations. Although most blending yards are equipped with automatic samplers and the derived samples are processed in the laboratory, the quality variation of the blended product may still be strong. This is caused by several reasons. First of all the process of sampling, crushing, dividing and analysis is time consuming. Results are available only with a delay of two to 24 hours. During this time blending is operated without knowledge of the main parameters. Conveyors with high throughput require expensive sampling systems capable of handling samples which are representative. The frequency of sampling needs also to be high in order to be representative. This results in high maintenance costs and also downtime of the sampling system.Online analysis of bulk materials has matured over time and today it can supplement but not replace laboratory analysis. As an example, J&C Bachmann has realised a coal quality monitoring system on the coal supply of a South African coal processing plant. The plant consumes ~42 Mt of coal per annum. The blending yard consists of two sets of three heaps where coal of six different mines is blended according to the factory’s requirement. From there, the blended coal is fed to the factory on two different belts.In 2010 the plant installed a TEXAS X-ray fluorescence analyser as a trial. It was tested under different conditions on several belts before the customer decided to install six TEXAS analysers on the feed belts to the stackers and two more analysers on the reclaimer belts. All analysers are installed directly on the belt and not on a substream.During the test period blending strategies were developed in close cooperation between the customer and J&C Bachmann. The use of the analysers in conjunction with the blending model has proven that the variation of the reclaimed coal quality was decreased significantly, which results in increased process performance and significant cost savings.CITATION:Bachmann, C C, Bachmann, J F, Cipold, M P and Ha, J, 2017. Online quality control of a coal blending yard, in Proceedings Eighth World Conference on Sampling and Blending , pp 125–128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017