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By Wu H. W, Jones S. J

Australia wide, over 40 fly-in/fly-out mining operations and other forms of long distance commuting now exist, with coverage of about 5000 employees. The substantial majority of these operations are in Western Australia, with some mines also located in Queensland and the Northern Territory. In recent years new large-scale mining operations have adopted the fly-in/fly-out approach and it is important to note that no new mining towns have been constructed in Australia since the township of Roxby Downs was built in the late-1980s to service the Olympic Dam mine. An examination of fly-in/fly-out mining operations in Australia has been undertaken. A detailed survey undertaken in 1990 has been reviewed and another intensive survey undertaken to establish emerging trends. Results from both company and individual employees point of view have been analysed. A section examines the views of professional employees and the influence of fly-in/fly-out on career development. Bus-in/bus-out coal mining operations are emerging in Queensland's Bowen Basin. These operations commute their employees into the mine site for compressed working schedules while the mine employees' families are domiciled in regional cities such as Mackay. A review of the issues associated with the development of long distance commute coal mining operations in Queensland's Bowen Basin is performed and two case studies examined.

Jan 1, 1997

By C J. Corbett

Many underground mining methods rely on blasted rock moving under gravity to report to extraction points. Mining of orebodies dipping between 20 - 45 degrees poses a unique challenge for mining engineers in that a dip angle in this range will not allow the movement of broken ore down the footwall to the mucking horizon utilising gravity. This is more so in cases where the natural angle of repose of the rock is less than the dip of the orebody. Hence, innovative mining systems are necessary to mine this type of orebodies. In Australia, the method of uphole retreat panel stoping is commonly used to extract orebodies in the dip range of 20 - 45 degrees and thickness range of 5 - 15 m. In the Zambian Copperbelt a method called continuous retreat updip stoping is used for orebodies with similar dips and thicknesses. The mechanised form of this mining method has potential for application in the metalliferous mining industry in Australia. In this study a comparison is made between mechanised updip (MUDS) and transverse retreat stoping (TRS) methods. A hypothetical nickel sulphide orebody located in Western Australia is used as case study. The net present value for mechanised updip stoping is seven per cent higher than that of transverse retreat stoping based on the assumptions applied. Initial results of this study indicate that mechanised updip stoping can be adopted for Australian mining conditions. However, lack of significant local experience with the method is often cited as a reason for not adopting it even in situations where it is clearly the best option.

Jan 1, 2003

By A Scott

Long before a modern mine commences operations it has already become a wealth of information. After start up, it can generate enormous quantities of data û especially with semi-automated data acquisition by instrumented mine equipment. However, much of this data is of limited use for evaluation of (potential) performance unless it links in some way to the site business model. An underlying reason for this waste of data is that the different cultures, financial, technical, community, environmental, etc not only have many areas of interest but also have very different conceptual models by which they evaluate performance. It is too ambitious to attempt to bring all of these cultures together û in a single step. However, the success of the Mine to MillTM project has demonstrated that substantial operational value can be added by using a more integrated approach to comminution. The next logical step is to integrate measurement and then to track performance from orebody model to saleable product and waste disposal. From resource to product also represents a path from very sparse, highly variable data to much more detailed measurement and more representative sampling. However, in both cases the data collected is strongly focused on the technical requirements û not on the business model. This paper considers how to define at least some of the key decision points in terms of some case studies. Performance data from many areas might be used to derive simple models which can then be used for forecasting and optimisation of planning.

Jan 1, 2002

By Hll J. K, Zhang Y. G

The wear mechanisms of impregnated diamond drill bit matrices are complex and believed to be the key point in solving drill bit self-sharpening problems. A method has been developed to find the change in c,, the wear rate of matrices having different fracture toughness K_ at the increment of drill pressure P. The worn surfaces of specimens were placed under a scanning electron microscope to examine the wear patterns and wear mechanisms at different pressures, and were compared with the worn surface of a practical drill bit. A model is proposed that within a wide range of pressures there exist two different wear mechanisms and three wear regions for cemented car- bide matrix materials. In region one (linear region), at low pressure, the major wear mechanism is plastic deformation in which the preferential wear of the binder phase of the matrix results in the loss of WC, tung- sten carbide particles. Wear rate is controlled by hardness, H as Archard's formula predicts. Wear enters region two and three (non-linear region) simultaneously as pressure is being increased. Consequently, wear transfers to fracture mechanism in which micro-fracture occurs at the root of wear grooves and the material is removed mainly in piece and mass. It has been shown fracture toughness K,, plays a more important role than hard- ness H. It is concluded that for a specific drilling condition, the pressure on the matrix should be carefully controlled and a balance between hard- ness and toughness of the material is essential for a steady drilling Condition.

Jan 1, 1989

By J Liu

In situ coal gasification is a method of extracting a high proportion of the energy value from coal without the need for mining. In situ conversion of coal to combustible gases is achieved by drilling wells into the seam, injecting gasification agents and initiating combustion. The product gases are then extracted to surface using production wells. These gases are clean energy sources for power generation, heating or synthetic fuel production. In situ coal gasification is of particular interest with respect to its lower environmental impact, potential application to otherwise inaccessible energy resources (ie offshore, deep deposits or beneath protected lands) and low capital intensity. Practical application of this clean technology is restricted primarily by lack of satisfactory quantitative descriptions of the processes involved, in particular the hydromechanical processes.In this study, three characteristic physical zones of an in situ gasifier are identified as the rubble zone, combustion front and virgin coal zone. Coupled mechanical processes of coal consumption and overburden collapse are used to describe the permeability profile in the rubble zone. Additionally, the redistribution of overburden load associated with coal consumption is accounted for with the formulation of a stress (compressive) dependent permeability profile, which is applied to the virgin coal zone. The model was implemented into and solved by FEMLAB, an advanced computer simulation tool. The flow process, according to DarcyÆs Law, is subsequently described in terms of permeability dependent injectivity. Injectivity is an indicator of flow velocity, which has been identified as a crucial factor in determining the commercial value of product gases from in situ coal gasification. The stress alteration to coal permeability was found to have a dominating influence on the flow process. This finding implies that a greater understanding of the in situ coal burning induced deformation of surrounding rocks would be of significant value in assessing the economic viability of applying this clean technology to potential sites.

Jan 1, 2004

This paper discusses the requirements for a successful simulation modelling study, and the steps involved in the modelling process. Advantages and disadvantages of simulation are described, and a case study highlights how not to go about it. Two other case studies, for a decline truck haulage and a block caving production operation, are used to illustrate the types of variables whose impact may be investigated. Typical results are presented to indicate the sorts of presentation styles the author has found useful for conveying study results to project sponsors. Standard spreadsheet charting techniques can be very useful in this respect, but the possibilities are limited only by the imagination of the study team.

Jan 1, 2000

By C Mark

Coal bursts involve the sudden, violent ejection of coal or rock into the mine workings. They are a particular hazard because they typically occur without warning. During the past two years, three US coal miners were killed in two coal bursts, following a six-year period during which there were zero burst fatalities.This paper puts the US experience in the context of worldwide research into coal bursts. It focuses on two major longwall mining coalfields that have struggled with bursts for decades. The Utah experience displays many of the ‘classic’ burst characteristics, including deep cover, strong roof and floor rock, and a direct association between bursts and mining activity. In Colorado, the longwalls of the North Fork Valley (NFV) also work at great depth, but their roof and floor strengths are moderate, and most bursts have occurred during entry development or in headgates, bleeders or other outbye locations. The NFV bursts also are more likely to be associated with geologic structures and large magnitude seismic events. The paper closes with a brief discussion of how US longwalls have managed the burst risk.CITATION:Mark, C, 2014. Coal bursts in the deep longwall mines of the United States, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 33–40 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014

THE manufacture of Portland cement on a commercial basis dates back to the year 1824, when Joseph Aspidin, of Leeds, patented his process. It was, however, only within the past 25 years that the cement of to-day commenced its history, and during that period manufacturers have constantly tried to improve the grade of cement.The introduction of the rotary kiln at the opening of this century was the starting point of rapid development in the process of manufacture, and in the quality of the cement produced.Following on the rotary innovation came the wet process. This at first was used only where the raw materials were of a soft nature; but to-day nearly all classes of materials can be treated by this method. Oompared with the dry process, it allows for greater refinement of raw materials, more intimate mixing, better chemical combination, and economy in fuel. Taking advantage of this, the manufacturers in England and America are in a number of cases substituting the wet for the dry process.Subsidiary machinery throughout the factories, such as crushing and grinding mills, have also been vastly improved. The chemists, too, have done their share in the work. Long and careful research has proved the necessity for accurate proportioning of raw materials, thorough mixing, and very careful burning. All these factors combined have given us the product of to-day, which is consistent within very narrow limits, and far superior to that of the beginning of this cement era.

Jan 1, 1926

By C L Humphrey

Biological monitoring programs for environmental protection require techniques that will provide both early detection of possible adverse effects, and assessment of the ecological significance of these effects. Monitoring techniques must include responses sensitive to the impact, that can be subjected to rigorous statistical analysis and for which statistical power is high. Such issues in baseline research of 'what and how to measure?' and 'for how long?' have been the focus of a program being developed to monitor and assess effects of mining operations on the effectively pristine, freshwater ecosystems of the Alligator Rivers Region (ARR) in tropical northern Australia. Application of the BACIP design, utilising a form of temporal replication, to univariate data (single species) and multivariate (community) data is described. For new ventures in Australia (such as mining), monitoring programs should be designed to establish with high probability that an impact on the ecosystem no greater than a prescribed amount has gone undetected - as opposed to simply allowing development to continue as long as 'proof' of impact is not available. Such a precautionary approach represents a shifting of the 'burden of proof' and would require with the BACIP design, a minimum number of baseline years in order to achieve some desired level of statistical power in a test for impact. Power analyses conducted on two to five years (depending upon the technique) of baseline data from streams of the ARR indicate that the BACIP design would not impose developmental constraints on mining and that a policy of reversal of the burden of proof would provide the cornerstone required for managing such development in an ecologically sustainable manner.

Jan 1, 1994

By S Basu, P M. Midhun

Electro-Slag Remelting (ESR) is a process capable of producing ingots with much lower centre-line segregation and better internal soundness than conventional ingot casting processes, as well as lower inclusion and sulfur concentrations. This process is commonly used for alloyed steels intended for critical applications like components of marine turbines, supercritical powerplants and rocket motor casings. It involves melting a metal electrode using electrical resistive heating in a slag pool and re-solidification of the resulting metal droplets beneath the slag layer, forming an ingot. Conventional ESR fluxes consist primarily of CaF2, Al2O3 and CaO, along with minor concentrations of SiO2, MgO etc. The emission of fluoride vapour from the molten slag causes several environmental and health problems, triggering a need to develop and reduce the fluoride content in the ESR flux. The present study aims to develop low-CaF2 alternatives to commercial ESR fluxes without compromising on productivity and the surface quality of the refined ingot. Thus, the modification in chemical composition needs to satisfy properties like electrical resistivity, viscosity and liquidus temperature, essential for efficient ESR operation. Since electrical resistivity and viscosity are highly dependent on the ionic structure of the molten slag, it is important to understand the effect of compositional modification on the structure of the flux. The present study employs Fourier-transform infrared spectroscopy (FT-IR) and Raman spectroscopy to investigate the structural variations in the modified fluxes, especially the effect of changing SiO2 concentration, in comparison with conventional CaF2-rich fluxes. Additionally, thermal analysis (Differential Thermal Analysis (DTA) and Thermogravimetric Analysis (TGA)) has been carried out to characterise the melting behaviour of the fluxes. The findings are compared with simulations carried out using the FactSage™ software, ver 8.3 (GTT Technologies, Aachen, Germany). Simultaneous analysis of liquidus temperature and the structure is expected to help in identifying the practical suitability of modified ESR flux compositions for industrial implementation.

Jun 19, 2024

By W Mez

The German mining industry uses different residues for backfilling and stowing. A hydraulic pipe conveying technology for these materials has shown advantages for the transportation into the mine. Pipeline conveying systems are able to bridge long distances, they save room within the underground workings and they save staff and costs. Absolutely necessary for successful use of the hydraulic conveying technology is the knowledge about the unusual non-Newtonian flow properties of solid/liquid mixtures like pastes and slurries. The flow resistance of these materials cannot be described easily by one viscosity. Owing to a yield point and a pseudo-plastic behaviour the viscosity changes with the shear rate and with the streaming velocity inside the pipe. Also these flow behaviours depend very sensitively on the liquid/solid-ratio, often so dramatically that gravimetric or volumetric dosing equipment is not in a position to control the production of backfill pastes. Quality changes of the solid raw materials (particle size distribution, density, mineralogical composition) lead to additional difficulties. The first experiences with hydraulic backfilling plants were troubled by plugged pipes, a bad backfill quality caused by unnecessarily high water content and high costs for chemical binders to solidify the backfill. The installation of viscosity controlled paste production leads to success with the hydraulic backfill technology. A development of the DMT, a bypass pipe-viscometer, has been the key technology. The system is able to analyse on-line, difficult, sticky and abrasive substances and determine their non-Newtonian flow properties. Because the system measures real physical values it is in a position to pre-calculate process relevant parameters like the pressure drop of the backfilling paste in the conveying pipeline. Newer types of the viscometer system also measure the slurry density and calculate its composition. These systems have proven a success controlling backfill paste production plants. They offer a secure prevention of pipeline plugging and a production of high quality backfill pastes with a water content as low as possible.

Jan 1, 1998

By Callaghan T

The Henty Gold Mine is located approximately 30 km north of Queenstown, at the head waters of the Henty River on the west coast of Tasmania at 41¦50'S, 145¦40'E on the Queenstown (SK 55-5) 1:250 000 and Sophia (8014) 1:100 000 map sheets (Figure 1). The mine is accessed from Queenstown along the A10 Highway and Anthony's Road. The town of Queenstown is located 260 km north west of Hobart on the A10 Highway, and

Jan 1, 1997

By I Lipton

The existence of metalliferous mineral deposits on the deep-sea floor has been known since manganese nodules were discovered in the Arctic Kara Sea in 1868. Modern exploration to define commercially viable base and precious metal deposits began in the 1970s and gained further momentum in the last decade. High grade deposits have been delineated but investors remain cautious, many considering deep sea mining projects to be riskier than terrestrial projects. This paper compares opportunities and risks presented by terrestrial mining projects with those presented by deep sea mineral deposits (Table 1). The Solwara 1 volcanic-hosted massive Cu-Au-Ag sulphide deposit, the Atlantis II Deeps sedimentary base metal sulphide deposit, and the Mn-Ni-Cu-Co nodule deposits of the north-eastern Pacific Ocean are used as examples. These are advanced deep-sea projects with published Mineral Resource estimates, on the cusp of development. Off-shore diamond mines in Namibia are also considered. These examples provide a basis for comparing exploration and geological uncertainty, the technical risks of proposed mining systems, and the potential environmental and social impacts. CITATION: Lipton, I, 2018. A comparison of opportunity and risk in deep-sea and terrestrial mining projects, in Proceedings Complex Orebodies Conference 2018, pp 102–105 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 21, 2018

By M I. Pownceby, N Karimian, A Frierdich

These may be found with goethite through mechanisms including direct substitution or coprecipitation of nanocrystalline phases. Understanding P incorporation in goethite has significant implications for Australia’s iron ore industry as it lowers their commodity value. The current study tests a novel low-temperature technique to extract P impurities from synthetic goethite phases under O2-free ambient conditions by utilising Fe(II)-catalysed recrystallisation. The objective of this study was to examine the effect of the Fe(II)-catalysed recrystallisation of goethite on the geochemical behaviour (mobility and speciation) of co-associated P. To achieve this, we tracked changes in labile P (aqueous and 1M NaOH extractable) concentrations over time in goethite suspensions which were reacted with Fe(II)aq for 14 days under circumneutral pH conditions and room temperature conditions. Temporal changes in Fe mineralogy were investigated via synchrotron-based X-ray absorption spectroscopy. Iron K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy confirmed goethite as the only mineral phase in P-free treatments while goethite (~86 per cent) and feroxyhyte (~14 per cent) were the main phases in 1.0 per cent P-containing treatments after a 14- day reaction with Fe(II)aq. According to our findings, the treatment of P-goethite with Fe(II) for a duration of 7–14 days, followed by a 24-hour extraction of the reacted solids using 1M NaOH, results in the removal of approximately 79.5 per cent of the initial P content. This removal encompasses both the aqueous fraction (~4.5 per cent) and the surface adsorbed fraction (~75 per cent) from the 1 per cent P-bearing mineral phase. Notably, this approach demonstrates an improvement in P extractability, with approximately a 10 per cent increase compared to the 1 per cent P-goethite sample that was not reacted with Fe(II).

Sep 18, 2023

The constructionhunnelling industry in Hong Kong has taken an upturn during the last few years due to the commencement of works to relocate the International Airport to Chek Lap Kok Island. The Airport Core Program consists of ten individual projects including roads, landfill, bridges and tunnels to build the airport and link it to the mainland of Hong Kong. Part of one of these projects is Cheung Ching Tunnel located on Tsing Yi Island. The proposed tunnel consists of a 1.6 km twin tube road tunnel through the island's central ridge, taking three lanes of traffic each way. Each tunnel is 16 m wide - (the widest road tunnel in Hong Kong) and are 10 m high. ICI Explosives (China) saw an opportunity to supply bulk explosives to the Cheung Ching tunnel and contacted ICI Australia to determine availability of a bulk system for tunnel blasting, and assist in its introduction. This paper discusses the methodology behind developing that bulk system to suit a large tunnel drill and blast operation. It also looks at the problems encountered along the way, from the development of the product to the application of the system in the tunnel and the eventual success of introducing a bulk system into a large tunnelling project.

Jan 1, 1994

By A Radici, M Attwill

The Dampier Port Upgrade Project (DPU) involves an upgrade to Hamersley IronÆs Parker Point iron ore port facility at Dampier, Western Australia. The $US700 million DPU Project will increase Hamersley IronÆs shipping capacity at Dampier from 72 million tonnes per annum (Mtpa) to 116 Mtpa. The DPU Project comprises a new car dumper facility and rail spur, an upgrade to the existing stockyard and conveying system, a new screen-house and a 450 m wharf extension with two new shipping berths and a new ship-loader. This paper discusses the innovative design and construction of the new car dumper facility, which is capable of automatically unloading 240 car iron ore trains at a rate of 10 000 t/h. The facility design is unique compared to more conventional designs currently in operation, and greatly improves operation and maintenance functions.

Jan 1, 2005

Mining and metals projects have tended to increase in both scope and cost to a point where many projects are Droperly designated as superprojects. Specialist engineer- constructors have developed organisations and systems to provide project management services during the design and construct phase of large projects. However, the engineer-constructor is also required to provide a wide spectrum of services during the evolution of large projects prior to the construction phase. Some common phases of pre-construction evolution are identified together with the associated types of specialised services which may be required. A project management team approach is described which has been developed for the design and construct phase. It is suggested that a modified matrix organisation could be adapted to the provision of special- ised services as well as to project management for ore-construction phases of the project.

Jan 1, 1980

By E T. Baker, J A. Resing, S L. Walker, V Ferrini, F Martinez, R Haymon

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. Enumerating active sea floor hydrothermal sites has been a challenge since their discovery almost 40 years ago. High-temperature hydrothermal sites are readily discoverable, primarily by detecting mineral-laden plumes, but working at these sites poses severe environmental and operational difficulties. Low-temperature vent fields, which may represent waning of venting from high-temperature systems, may be more accessible but are more difficult to locate. Over the last decade, however, oxidation-reduction potential (ORP; aka Eh) sensors capable of detecting minute concentrations of reduced hydrothermal chemicals have been successfully used to pinpoint such fields. In this extended abstract, we use ORP anomalies observed during continuous (towed sensor) plume surveys to estimate site frequency along four intermediate- to fast-spreading ridge sections. From these data, we estimate site frequencies between five and 16/100 km for these ridge sections. Previous camera surveys on the fast-spreading East Pacific Rise support these frequencies. These rates are much greater than the frequency of ~0.5–5/100 km, generally increasing with spreading rate, derived from well-surveyed ridge sections in the InterRidge database (InterRidge, 2014). The higher frequencies arise because ORP sensors are able to distinguish between sites as close as ~1 km and identify sites with negligible or no optical plume signal.CITATION:Baker, E T, Resing, J A, Martinez, F, Haymon, R, Walker, S L and Ferrini, V, 2015. How leaky are oceanic ridge axes? A new assessment of the spatial density of submarine hydrothermal discharge, in Proceedings PACRIM 2015 Congress, pp 3–8 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By E Acu±a, B Prosser, R Alvarez, K Wallace

This paper describes the ventilation analyses performed for the access tunnels at the New Level Mine project (NLMP) at CodelcoÆs El Teniente operation outside of Rancagua, Chile. This new mine is anticipated to reach a final production of between 137 and 180 kt/d. Production from the NLMP is scheduled to start in the year 2017. The main access tunnels (MAT) are approximately 9 km in length, with one for personnel and supply access and the second one for ore extraction through a conveyor system. These two tunnels are a critical component of the initial stage 1 development and will be constructed independently of the existing mine workings. The tunnels were originally designed to be constructed with two tunnel boring machines. However, later analyses changed the construction approach to a conventional drill and blast technique. Because the design included two mid-tunnel ramp-to-surface connections, conventional mining methods would allow for development of the tunnels with multiple working faces to achieve a more rapid schedule. This paper presents the initial baseline considered for the ventilation design and the optimisation methodology applied by Codelco to minimise the airflow and pressure requirements of the ventilation system. Modifications to the design resulted in the addition of strategic airways and raises that could provide a saving of approximately 1 MW, when compared to the original design.CITATION:Acu±a, E, Alvarez, R, Wallace, K and Prosser, B, 2013. Ventilation considerations for the new level mine project access tunnels, in Proceedings The Australian Mine Ventilation Conference , pp 203-206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By Baker G

Chromite was recorded among the rare minerals in the natural beach sand concentrates on the coast of Northern New South Wales by Whitworth(l) in 1931, and the commercial production of zircon and rutile from these beach sands has yielded concentrates of ilmenite with small amounts of chromium. The chromite is a detrimental impurity in the utilisation of the ilmenite, and the difficulties that attend the separation of the small amount of chromite from the ilmunite have raised suggestions from time to time that chromite occurs with ilmenite in composite grains. The absence of such composite grains and the nature of the chromite grains has been indicated by the following mineragraphic examination of magnetic concentrates containing chromite which were prepared by the C.S.I.R. Ore Dressing Laboratory, Melbourne University, from ilmenite concentrates from beach sands at Norrie's Head, County Rous, New South Wales and Stradbroke Island, Queensland.The magnetic concentrates from each locality are divided into five fractions, and the No. 1 concentrate is the most highly magnetic and the tailing the least magnetic. Chromium assays as determined by the Ore Dressing Laboratory are as follows:-

Jan 1, 1948