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By H Yuan, H Tian, Y Zhang, Z Wang, C Wang

Submerged arc welding (SAW) is one of the significant metal-joining processes for manufacturing marine vessels, steel pipes, and offshore structures with high deposition rate and engineering reliability. Welding flux serves several essential functions, including atmospheric shielding, arc stabilisation, bead morphology control and weld metal (WM) refinement. Therefore, from a thermodynamic point of view, the focus for flux design and WM compositional/microstructural modification has been placed to elucidating the transfer pathways and mechanisms of major alloying elements, such as Si, Mn, Ti and O during welding. To this end, a thermodynamic model has been established to predict alloying element contents in the WM. Such functions are enabled by the physicochemical properties of the fluxes, which are inherently rooted in the nature of the fluxes. A unique yet systematical investigation, including physicochemical property changes and structural evolution behaviours, has been conducted over the wide range of fluxes applied to actual welding of EH36 shipbuilding steels. Combined with spectroscopic methods, structural behaviours of network formers such as SiO2, Al2O3 and TiO2 and network modifiers such as MgO, MnO and CaO have been illustrated. Viscosity and ionic conductivity have been found to be positively associated with the degree of polymerisation.

Aug 21, 2024

By B Belle

"Mines around the world are inherently and operationally diverse. Current methodologies for the design of mine ventilation and cooling infrastructure involve controlling major safety and health hazards. Globally, it can be estimated that mine ventilation systems from various commoditiescirculate over 150 000 m3/s of exhaust air through shafts. Additionally, over 2 000 000 workersare transported every day through shafts in labour-intensive mining countries like China, India,Southern Africa, and the Americas. A key objective of this paper is to share experiences and provide a case for the revision of ætime-honouredÆ ventilation design parameters based on a benchmarking exercise on design exhaust shaft velocity from various global operations (gold, diamond, platinum, coal and base metals). An active fi eld observation on exhaust shaft velocity has indicated that, regardless of the commodity or continent where the mine operates, almost all life-of-mine (LOM) design parameters provided are in the same range of 20 m/s to 22 m/s, which is not convincing considering signifi cant variations exist in shaft depths, geography, commodity, operating and capital costs. From a due diligence perspective, there are no documented views that are available on the most widely used design exhaust air velocity. Based on the global exhaust shaft velocity data, it is noted that a significant portion of shaft velocities are outside the current design velocity of 20 m/s (some operating up to 30 m/s) and other signifi cant portions of the exhaust shafts operate in the critical velocity range. In the case of Australian coal mines, limited data suggests that none of the mines have ever reached the LOM design exhaust shaft velocity. It is self-evident that when the shafts are not operating at their design quantities either the mine system resistance is low or the ventilation and main fan is operating ineffi ciently. The most common reasons given for not reviewing the shaft system were, ætime-honouredÆ design parameter are being used and cannot be changed, mine fan pressure limits, possible fan blade damage, possible spontaneous combustion risks, leakage or simply did not consider such a possibility. In conclusion, the study has reiterated the historic lessons that a safe and expensive airway should not be utilised uneconomically by circulating too litt le air through it."

Jun 1, 2012

By J Seppelt

The Kanmantoo Copper Project is owned and operated by Hillgrove Resources Limited and is situated in the Adelaide Hills region in South Australia. Mining in the area has taken place off and on over the last 140 years to recover metal from both copper and lead-zinc ores. This paper focuses on the commissioning, ramp up and future outlook for the copper concentrator at the Kanmantoo Copper Project with major focus on issues encountered and operating performance achieved to date.CITATION:Seppelt, J, 2012. Commissioning of the Kanmantoo Copper Concentrator, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 127-136 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

This paper discusses equipment replacement strategies and specifically addresses the upgrading of technologically superseded equipment. The process of equipment replacement evaluations is reviewed, and areas have been highlighted where currently accepted practice results in a bias towards retaining existing equipment longer than otherwise justified. The Discounted Average Cost Method is described and the advantages of the technique for this style of decision making discussed. Several key issues influencing the replacement evaluation are also presented together with examples from recent consulting work.

Jan 1, 1992

By S Hille, J Karageorgos

With the increased variability of todayÆs large-scale mining operations, consistent flotation performance is important to improving and sustaining overall recovery through the circuit. The Newcrest Telfer Mine has implemented advanced process control technology to obtain stable level operation and consistent mass pull in the copper rougher and scavenger flotation circuits. The final result has been an overall reduction in variability, which impacts on both copper and gold recovery. This paper describes the methodology and implementation of the improvements in control at the Newcrest Telfer Mine as being an essential part of the business for minerals processing.

Jan 1, 2007

By Waterhouse BJ

Occurrence data of Tastubian,Sterlitamakian, and Aktastinian (all of Sakmarian Stage of Early Permian) brachiopod genera are analysed by Q-mode cluster analysis, principal component analysis, and discriminant analysis based on presence or absence of genera. Five faunal provinces and their corresponding generic associations persisted throughout the Sakmarian Stage. The additional Sasian Province incorporating the Lhasa and Shan-Thai terranes became recognisable in Sterlitarakian and strengthened in òAktastinian, implying a Tastubian-Sterlitamakian rifting event, followed by subsequent northward drift and divergence from Gondwana, and convergence with Laurasia. The nature of Permian 'Tethys' is discussed on the basis of faunal migration and abrupt changes of faunal provinciality in Lhasa and Shan-Thai terranes.

Jan 1, 1990

I congratulate The Australasian Institute of Mining and Metallurgy on its decision to hold its Annual Conference here in Western Australia. Western Australia, with its abundant mineral and energy resources, plays a key role in the Australian mining industry... and Western Australia will continue to figure prominently in this vital industry for many years to come. The success of our gold, iron ore, bauxite, mineral sands and other primary industries has enabled Western Australia to contribute significantly to Australia's export revenue and, therefore, to the nation's economic strength. The State's mineral wealth has also provided the impetus for a recent surge in mining related activity, including a dramatic increase in downstream processing of our raw materials. Billions of dollars worth of new project investment is either committed or awaiting final approval - and most of this new investment is a direct result of a healthy and vibrant mining industry. The North West Shelf Project - which has been providing natural gas for homes and industry in Western Australia since 1984 - has also played a key role in stimulating industrial development. The availability of abundant, competitively-priced gas from the North West Shelf has - along with the availability of other raw materials - made Western Australia a more attractive proposition for industrial investment. The company I represent, Woodside Offshore Petroleum, is operator of the North West Shelf Project on behalf of the Project's six Joint Venture Participants - Woodside Petroleum Ltd, BHP Petroleum (North West Shelf) Pty Ltd, BP Developments Australia Ltd, Chevron Asiatic Limited, Japan Australia LNG (MIMI) Pty Ltd and Shell Development (Australia) Proprietary Limited. The theme for this Annual Conference: "Excellence - the key to the continued success of the Australasian mining industry" is appropriate to the North West Shelf Project. The pursuit of excellence has been a hallmark of the Project. The Joint Venture Participants have been conscious of the need for stringent quality control at all stages of development. Procurement and purchasing policies, for instance, have demanded strict adherence by contractors and suppliers to the highest standards and specifications.

Jan 1, 1989

By D Mee

The Western Mining site at Olympic Dam, near the community of Roxby Downs in South Australia is one of the largest orebodies of its type in the world. It contains known reserves of over 10.6 M tonne of copper, with economic secondary metals including uranium, silver and gold. In 1996, an expansion project was commenced to increase mine production approximately threefold, to produce 200 000 tonnes pa of copper, 4600 kg pa of uranium oxide, 3600 kg pa of gold and 50 000 kg pa of silver. This expansion included both underground mining and surface processing investment. Because of the scale of operations, it was decided that ore should be transported underground by a railway system. In July 1997, ALSTOM Automation and Control Limited (then Cegelec Australia Limited), was awarded the contract to deliver a control system to manage and automate the rail haulage system for Western MiningÆs Olympic Dam Mine, as part of this major upgrade and extension project. This paper explains the overall design and the approach taken to implement route selection, route locking, train interlocking and track topology using normal industrial control equipment such as Programmable Logic Controllers. Included is a discussion of how this automation has improved the productivity of the haulage system by more than 15 per cent.

Jan 1, 2000

By J Berg, M Hahn, R Winkel

Imaging sensor systems designed for the mining and minerals industry incorporate different physical measurement technologies that can be used to detect the machine environment, such as laser, ultrasonic/sonar, video and RF-sensors. The underlying physical measurement principles cannot be employed in most applications near the face without regular maintenance due to the harsh environmental conditions like dust, dirt or moisture. However, that is the area, where imaging sensors are most valuable to the machine operator. In the domain of 2D radar sensors these have been either restricted by the angular coverage area or by limited adaptability of signal processing algorithms. The unique full digital solid state design will establish a generation step in mining applications.In order to fill this gap of terrain imaging sensors, the Institute for Mining and Metallurgy Machinery (IMR) of the RWTH Aachen University, in cooperation with the radar company indurad, developed an imaging sensor based on radar technology employing the digital beam forming (DBF) concept. Through multiple transmitting and receiving antennas the sensor delivers high accuracy range and angular information. Using adaptive digital signal processing with multiple imaging algorithms and target detection routines, data of the surrounding environment can be used to enable automation functions in mining.A comprehensive range of radar scans in different environments have been evaluated and benchmarked by using laser scanners. Accuracy measurements in range and angular direction have shown minimal differences. Experimental measurements have been performed at slopes, on conveyor belts and hot cement clinker silos. The experimental system uses a frequency modulated continuous wave (FMCW) front-end combined with a processing unit for signal analysis and target detection.

Sep 26, 2011

By G S. Beros

In 2019 the Chinese Ministry of Ecology and Environment issued guidelines promoting the implementation of ultra-low emissions in the iron and steelmaking industry. These guidelines aim to drive improvements in air quality through the reduction of particulate matter (PM), sulfur dioxide (SO2) and nitrogen oxide (NOx). Secondly, it also represents an initial means to commence decarbonisation of the industry. The ultra-low emissions guidelines propose that well over 80 per cent of China’s production capacity will achieve these targets by 2025. In response, many sintering operations have implemented numerous improvements to the process that result in significant efficiency gains. Of note is the adoption of deep bed sintering where, with some modifications to equipment, the sintering bed depth is increased resulting in sizable reductions of SO2 and NOx emissions. This paper will also provide an overview of the requirements to introduce deep-bed sintering into an operation and highlight test work completed which quantifies the resultant reduction in emissions.

Nov 8, 2021

By R Yong, A McEwan, D G. Miljak, D Milinkovic, A Curtain, P J. Coghill, R Stefulj, B Lovric, G Roberts

The CSIRO has pioneered the development and use of certain classes of magnetic resonance (MR) for mining applications. The MR technique is a radio frequency-based spectroscopy that provides highly quantitative measurement of selected ore minerals. MR has many inherent advantages for bulk sensing in mining applications, including deep sensing penetration into most bulk ores with the use of non-contact sensors that are robust and tolerant of demanding mine conditions. The highly discriminating nature of the technique also provides the very desirable attribute of robust and simple calibration, that can often be performed prior to sensor installation. Rapid sensing (within seconds) at very low grade (few hundred ppm Cu) has been demonstrated, as well as sensing at high tonnage rate. Besides sorting applications, MR may also be applied to preconcentration applications involving very large volume sensing including: (i) haul truck sensing using portal arrangements, where truck destination assignment may be dynamically determined based on the truck grade, (ii) in-pit gantries used for loading trucks that may similarly be equipped with sensors for truck assignment and (iii) deep mine bench sensing, recently progressed through a CRC ORE project, where local bench grade is determined at the few-metre lateral scale and at depth prior to blasting, to aid selective blasting and ore extraction. MR sensor prototypes have been developed for each of these applications and have been tested in laboratory or limited field conditions. To inform the value proposition for truck or bench sensing, initial analysis of truck assignment improvement based on an analysis of in-situ mine bench grade has been performed for a porphyry style deposit. The prototype sensors, preliminary results and future technology development and objectives will be described.

Nov 10, 2020

By S Mitra, D O’Dea, N Barrett, T Honeyands, P Zulli

The steel industry continues to explore and demonstrate technologies that decrease its greenhouse gas emissions, especially in blast furnace ironmaking where alternate operating conditions will be required. As the furnace has been optimised over many years, it is approaching the minimum fuel rate possible with coke and Pulverised Coal Injection (PCI). Alternative operating conditions are therefore required to further decrease greenhouse gas emissions. Because of this, hydrogen has been proposed as a reducing agent in the blast furnace. Injection of hydrogen through the tuyeres was assessed using a comprehensive 2D blast furnace global model. The model was calibrated to a blast furnace operating with PCI as a base case and various approaches to hydrogen injection assessed, with a particular focus on displacing PCI. The maximum hydrogen injection rate of 19.5 kg H2 per tonne of hot metal was predicted, limited by decreases in the raceway adiabatic flame temperature and top gas temperature. Internal blast furnace conditions, such as gas composition and reduction degree were also predicted. Holistic analysis was performed to estimate the effectiveness of hydrogen injection on reduction of greenhouse gas emissions. Based on these results, the changes in blast furnace operation and emissions under hydrogen injection are discussed.

Nov 8, 2021

By M Lak, R Amiri, A Haratian, M Asghari, S Haji

Dry magnet separators are used to upgrade and beneficiate a wide variety of minerals such as hematite and magnetite materials. In recent years advances in dry magnetic separators have improved their performance. Fine particle separation is one of the main areas which still remain weak. This paper will present a new design of fine particle drum separators which used for particle size less than 3 mm. A big problem in processing of iron ore is the grade and recovery of mineral values in the fines fraction. The new design high efficiency drum separator is developed to handle fine feeds. In this drum separators both of the drum shell and magnetic yoke rotate in opposite direction. the results showed that when the material feed size was = 1298 μm, drum shell speed was 42.5 rev/min, magnetic yoke speed was 100 rev/min and the maximum intensity of magnetic field was at = 30° the feed grade increased from 50.87 to 65.67 in concentrate box, increase to 60.45 in middle box and tail grade was 24.44. The total achieved recovery for both concentrate and middle box was 81.89 per cent.

Nov 8, 2021

By M Jones

Legacy tailings storage facilities exist within operating mine sites across Australia. These tailings storage facilities are often viewed as rehabilitation liabilities but with considered assessment may prove to be a resource. Extraction of such a resource might add value to operations by providing cash flow during the development of new mines; providing supplementary mill feed for existing mines undergoing step changes in operations; and supporting mine closure activities. Hellyer Gold Mines is successfully extracting and reprocessing sub-aqueous material from legacy tailings storage facilities at their Hellyer operation in north-west Tasmania. The Hellyer tailings storage facilities contain poly-metallic material from the Hellyer and Fossey underground deposits dating back to the 1980s as well as material from tailings reprocessing activities by other operators of the Hellyer site. Hellyer Gold Mines is reclaiming sub-aqueous material using cutter-suction dredgers and reprocessing on-site. Hellyer is the only operation of its type in Australia and few such operations exist worldwide. Key learnings around the estimation of a resource for legacy tailings storage facilities have been acquired at Hellyer that can be applied to the assessment of other tailings storage facilities. The application of dredging as a mining method at Hellyer is delivered through collaboration with experts from outside the mining industry under the direction of a mining engineer. Key elements required for the planning and delivery of safe and efficient dredging inside tailings storage facilities have been identified at Hellyer and are presented to provide a road map to the development of other dredging operations.

Sep 1, 2024

By S J. Schafrik, M Long

There are several factors that are increasing the need for new graduates to be ready to design and manage more autonomous operations at mines. Autonomous controls and systems range from the start-up, control, and shutdown of processing plants to the autonomous operation of vehicles. These operations require the workers, engineers, and management to have additional skills for programming, debugging, tasking, and maintaining the equipment. The future survivability of many mining operations will be influenced by a company’s willingness and ability to understand, accept, and utilise this technology for safe and productive operations. This is an educational opportunity and challenge that needs to be addressed throughout the student’s experience, from first year to graduate level. This paper discusses the lessons learned from a decade of multidepartment effort at all student levels and many courses that are able to incorporate data science, controls, and autonomous design into the already topic-rich national curriculum. This approach also exposes other engineering disciplines to the mining industry which is a valuable recruiting tool for talent outside of the mining engineering departments.

Sep 1, 2024

By D Bradshaw, R Dunne, S Farrokhpay

It is well known that clays affect the flotation performance, and many of the refractory gold ores around the world contain clay minerals. Therefore, an ore sample from the Carlin Trend was selected for this study as these ores contain large quantities of clays. The presence of clay minerals in an ore makes it susceptible to a range of variables, such as the solution chemistry determined by pH and the chemistry of the rheology modifiers. The viscosity of the ore slurry was measured as a function of solid concentration and particle size distribution, in addition to using different rheology modifiers and pH regulators. The results were correlated with the ore flotation performance. It was found that various reagents known commonly as dispersants or rheology modifiers have different effects on the ore slurry viscosity. This study revealed that the gold flotation recovery can be improved by changing the pulp rheology.CITATION:Farrokhpay, S, Bradshaw, D and Dunne, R, 2013. Rheological investigation of the flotation performance of a high clay containing gold ore from Carlin Trend, in Proceedings World Gold 2013, pp 333-340 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By J Nantel

Planning of modern mines entails considerable challenges in the areas of ground control, materials handling, safety, environment, equipment and personnel. Many orebodies are not economical unless efficient mining systems are used to win the ore. Relentless pressures are placed on mine operators to force them to become more productive and to make mines more competitive in modern economies. This has generated an intense drive to adopt technologies that rely on a greater degree of mechanisation, automation and computerisation. There is no turning back; high technology in mines is here to stay: computer controls and monitoring, computer aided mine design, information management systems, etc. During the past 20 years significant advances have been made in the areas of mine design, mine equipment and geomechanics. One could rhetorically ask if the advances in mine backfill technologies have kept pace with developments in other sectors of the mining industry. This paper will look at a few key mining technology sectors and will compare the relative progress of backfill technology to these sectors.

Jan 1, 1998

By M Hedley

Tracking plant and personnel in underground environments provides multiple potential benefits for a mine including increasing safety, better monitoring of production, traffic control, and in the future monitoring and control of autonomous vehicles. The main techniques for wireless tracking are to use radio frequency identification (RFID), signal strength based techniques, and time of arrival (TOA) based techniques. RFID does not provide continuous tracking and signal strength techniques have poor accuracy in the complex radio propagation environment present in mines. TOA based techniques are potentially the most accurate, but most current equipment does not realise the potential of the technique. CSIRO has been developing the wireless ad-hoc system for positioning (WASP) system for wireless tracking in a range of challenging environments including underground mines. WASP has been licensed for sporting applications and has delivered encouraging results in early trials for a surface and an underground mining application. The system utilises a number of ‘anchor nodes’ that are placed at surveyed fixed locations within the mine, and tags attached to plant or personnel to be tracked. The system provides an ad hoc data communication network, thus wired data connections are not required to the anchor nodes. WASP uses transmissions in the 5.8 GHz ISM (instrumentation, scientific and medical) frequency spectrum to perform highly accurate ranging between nodes, hence tracking of tags. The localisation performance of the system depends upon the radio propagation environment, ranging from 0.1 m in low multipath conditions. In this paper we describe the WASP system and provide results of initial testing in an underground mine that shows that the system achieves high ranging accuracy, hence localisation accuracy.

Mar 21, 2011

By D Kent

The introduction of digital technologies into the underground mining industry, in both coal and hard rock mining, has enabled many high bandwidth applications to be adopted by mines.Digital networks based on 802.11 b/g/n open Wi-Fi standards allow for many applications to be run over a single communication backbone. One important application has been tracking personnel and equipment via RFID tags. This tracking application has in turn formed the basis of a Proximity Detection System (PDS) or Collision Avoidance Systems (CAS). The paper discusses the growth in digital technology as the communication backbone in underground mines which has allowed the ‘convergence of technologies’ that has been occurring in the general business world to be available to underground mine operators. Then the paper will focus on the use of the technology in the increasingly important are of risk control around mobile plant underground. The specific use of digital devices for proximity detection, in both hard rock and coal mines, to provide a system that can deliver an additional level of control to the risks associated with people-vehicle interactions underground is discussed. The initial implementation of PDS in the hard rock mining environment is based on two zones of detection, required for large and relatively high speed vehicles. Information will include:•the principles of the underlying technology,•installation learnings and effectiveness, and•change management methodology and issues.The most recent development to integrate Mine Site Technologies (MST) PDS with Frederick Mining Controls’ HazardAvert® System to extend the overall Proximity System’s functionality in hard rock mines and for use in coal mines is overviewed.

Mar 21, 2011

By R H. Sibson

Magmatic and/or hydrothermal fluid systems in island or mountain arcs self-organise to critical states subject to perturbation by changes in the regional stress, which plays a controlling role in the containment of overpressured fluids. Whether the magmatic arc is under compression (eg Andes, northern Honshu) or extension (eg Taupo Volcanic Zone, New Zealand) is a key factor controlling the ease of magmatic or hydrothermal fluid ascent. Abrupt changes in the stress regime have the potential to induce major episodes of fluid redistribution. Large earthquake ruptures along plate boundaries may induce such changes over broad areas, also contributing to fluid redistribution by renewing fault permeability along the causative rupture zone or reactivating distant fault-fracture permeability by shaking from radiated waves. High-resolution geophysical investigations of active arc systems and the subduction thrust interface underlying their fore-arcs reveal repositories of overpressured hydrothermal fluids. In active magmatic arcs under compression such as NE Honshu or Cascadia, there is evidence for a heterogeneous distribution of overpressured hydrothermal fluids in the middle-to-lower crust trapped around the base of the upper crustal seismogenic zone. Investigations of the subduction thrust interface responsible for great (Mw = 8.0) ‘megathrust’ earthquake ruptures has revealed in some instances (Cascadia, SW Japan) the existence of a belt of non-volcanic tremor (NVT) with accompanying slow slip episodes defining the base of the megathrust interface at 40 ± 5 km and 350°C??-??550°C. Aqueous fluid at these depths is likely derived from dehydration reactions accompanying the basalt-eclogite transition in subducted oceanic crust. NVT sequences in the hanging-wall above the interface may be defining migration pathways into the overlying crust.The potential for eruptive episodes in magmatic arcs and redistribution of hydrothermal fluids is assessed in the light of the stress changes that followed the 2011 Mw9.0 Tohoku subduction thrust rupture which extended along strike for over 500 km and down-dip for over 150 km, with maximum slip of c 50 m.

Aug 22, 2011