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By F Brenguier, R A. Lynch, G Olivier

The seismic velocities of intact rock are dependent on the applied stress. Unfortunately, the low susceptibility of seismic velocity to stress changes mean that changes in seismic velocity have to be measured extremely accurately to infer stress changes from them. Previously, it was thought that measurements of this accuracy could only be made with active sources or repeating earthquakes. In this paper, we show that the noise generated by mining activity can be used to construct virtual seismic signals with which we can measure changes in seismic velocity accurately enough to see the short- and long-term effects of a production blast on the surrounding medium. The time-dependent velocity variations achieved with this method show that the blast caused weakening of the rock mass for the rock within a radius of 200 m of the blast. The weakening is healed by confining stresses over a period of five days, after which permanent changes in the seismic velocity can be seen. The size and spatial distribution of the seismic velocity changes were compared to modelled changes in static volumetric stress, which supported the notion that seismic velocity changes can be used to measure the redistribution of stress after a blast. The results of this study indicate that this method can be a powerful tool to evaluate the evolution of stress in a mine at a relatively low cost as the data that it uses would normally be discarded.CITATION:Olivier, G, Lynch, R A and Brenguier, F, 2016. Measuring the redistribution of stresses resulting from new excavations with ambient seismic noise correlations, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 873–878 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

As mines become deeper, the problems of heat in the workplacebecome more acute. An important response from the industry hasbeen the widespread adoption of microclimate cooling such asair-conditioned cabins. However, not all work in mines can becompleted from inside an air-conditioned cabin, and in any event,it is still important to keep the ambient air in the mine outside ofany microclimate to a safe temperature. An important method forbringing workplace temperatures under control is the appropriateuse of refrigeration. The application of refrigeration inmechanised mines has been recently described (Brake, 2001;Brake and Fulker, 2000). This paper provides an overview ofsome of the important engineering considerations in thespecification and selection of mine refrigeration plants. Thepurpose is to provide a basic understanding of refrigerationprinciples, practices, terminology, hazards and opportunities formining engineers or other personnel who may need to beinvolved in the introduction of refrigeration onto a mine site.

Jan 1, 2001

By Propster M, Choudhry M

THIS note gives comments on the paper by Kitaev et al on p. 68 of this book and compares results with those obtained by ourselves. We wish to say that the authors are to be congratulated on their sophisticated approach to an important problem and that it complements our efforts on flow maldistribution.1-5 It is our view that Eqs. (1)-(5) on p. 69 are impressive, but unfortunately with present day computers and computational facilities, it would be quite impractical to contemplate the numerical solution of these. Eq. (8) in the authors' paper, on p. 70, does provide the logical starting point for tackling flow maldistribution problems and strictly speaking this equation is more accurate than Eq. (1) in our paper in this book. We note in passing that there is direct experimental evidence to support the contention that our Eq. (1) is at least a reasonable approximation and one may question in a practical sense whether the refinement afforded by Eq. (8) in the paper by Kitaev et a/ is justified. While one must readily accept the appropriateness of Eq. (8) of Kitaev et al as a starting point, the subsequent mathematical manipulation by the authors is open to serious criticism. In order to solve this complex, non-linear equation Kitaev et al postulated irrotational flow, which afforded considerable simplification. One can argue simply on physical grounds that the assumption of irrotational flow is inappropriate, a fact which should be readily apparent on inspection of the flow fields shown in Figs. 2 and 3 of Kitaev's paper. It follows that while the starting point through the use of Eq. (8) is correct the results derived from this starting point may be suspect because of the erroneous nature of the irrotational flow assumption.

Jan 1, 1975

The Kanowna Belle deposit was discovered in 1990 following encouraging assays from soil sampling and RAB drilling. At the end of September 1993, diamond drilling had been completed to a vertical depth of 1,000 metres and a resource of 22 million tonnes grading 5.73 grams of gold per tonne containing a million ounces of gold had been defined. The deposit remains open at depth. Pre-production mining for the open pit began in November 1992, construction of the oxide treatment plant began in January 1993 and the first gold was poured in September 1993. Sulphide ore roasting commenced in December 1994 and the underground mine development commenced in July 1995. The Kanowna Belle project is owned by the Golden Valley Joint Venture (GVJV), an unincorporated joint venture with equal shareholdings between North Gold (W.A.) Ltd and Delta Gold N.L. North Gold are the managers of the development and operations and Delta Gold are the managers of exploration throughout the GVJV tenements.

Jan 1, 1990

As an environmental "pollutant", noise is different. For one thing, it is localised (as opposed to transfrontier) and, for another, relatively low levels can trigger very strong human reaction. The reactions, which are annoyance-based, range from mild to violent and do not always correlate well with the levels experienced. This paper draws on technical aspects of noise to consider control and control principles and balances them with the subjective nature of the perceptions and reactions. It is critical to bear in mind that health effects resulting from noise are secondary to the primary human reaction. It is also important to appreciate that annoying noise levels are usually well below those which cause hearing loss. Large mines tend to be remote from cities and towns and the country surrounding such mine sites is often inhospitable. In general, residences near large mines are committed for use by mine personnel and annoyance from mining noise would be rare. Noise problems at long term operations are often a result of secondary activity or land use. As a pioneer mining community develops, secondary and service industries may be established and a township created. With changes in way of life, the perception of problems also changes. Therefore, it is never too early to plan for noise abatement, particularly because noise is only one of a number of environmental and community concerns. Ihny environmental problems are associat- ed with development or expansion of smaller open cut facilities such as hardrock quarries. There is an ever-present need to reduce product cost by mining or quarrying deposits close to the end user and many local authorities have to operate quarries for undertaking their civil engineering responsibilities.

Jan 1, 1987

By Lott JB, Scuffham JB

Until very recently the application of solvent extraction to. the recovery of metals has been considered only for ithose operations where no other process was available. In general, .these operations, have involved metals such as 'f uranium or the rare earths, where the value of metal recovered has been very high. As a result, the tendency has been to consider solvent extraction as a very specialised, high cost technique with minimal application in the base metal industry. Since the mid-1960's this attitude has had to be changed drastically with the development of solvents specifically designed for the selective extraction of individual metals such.ascopper. The result is that solvent extraction must now be regarded as a proven hydrometallurgical technique for the recovery of base metals, and in particular copper. The first significant event in the application of solvent extraction to base metals was the production by General M. Inc. of a compound, designated LIX-63 (R)(1), which was a specific extractant for copper from ammoniacal sns. This did not find a wide application, however, because copper solutions with a pH in the applicable range we more readily treated by conventional techniques.

Jan 1, 1970

The purpose of this paper is to outline the basic policy problems for good community relations programmes in the resource extraction industries of Papua New Guinea. The main focus of the paper will be on defining and analysing those problems which lie on the landowner side and which are still not widely understood within the resource extraction industries despite several decades of turbulent experience. Many of the companies operating in the resource extraction industries of mining and petroleum and gas have in recent decades adopted, by choice or necessity, 'good corporate citizen' policies. Some of these companies now pursue ethical business, environmental and community relations policies. Some have adequately funded and well-trained staff in their community relations departments. Although different industry sites scattered over Papua New Guinea show significant differences in their experience of social conflict, I argue here that a good deal of this variation has less to do with the differences between the companies' public relations policies and their effectiveness and more to do with the conflict causing features of indigenous society. Experience suggests that even a company well-equipped with good intentions, good policies and good staff may experience serious difficulties in maintaining good community relations in Papua New Guinea. Many of these difficulties, I argue, can be traced to causes that lie, essentially, within the structure of Papua New Guinean communities and in the customs and social relations of Papua New Guinean peoples. Accordingly the attention of this paper is focussed on the conflict causing aspects of Papua New Guinean society. It is true, to the point of being a cliche, that Papua New Guinean societies are oriented very strongly towards achieving consensus and social harmony. In this regard Papua New Guinean communities differ significantly from, say, Australian communities. My purpose here is not to denigrate this aspect of Papua New Guinean societies but, rather, to point out that the drive for consensus is driven by the desire to avoid its opposite, dissensus. This paper sets out to define the dissensual aspects of Papua New Guinean societies and my special interest is in those conflict producing aspects of Papua New Guinean societies that are most resistant to the mechanisms that are designed to create social harmony. A survey of the recent history of industry and community relations in Papua New Guinea indicates that there are three main factors present on the landowner side which are liable, separately or through their interaction, to cause difficulties. These factors are respectively generational challenge, social boundaries and custom variability and I shall discuss each of these in turn.

Jan 1, 1997

The mining industry is quite often faced with declining selling prices for its products in the face of rising prices for the input cost resources that it uses. Blasting is a key activity within the mining system and has a vital role to play within the Mine to MillTM concept. It is therefore important that blasting makes a positive contribution to mine profit and productivity. There are several variables involved in considering the profitability and productivity of blasting. The rock types and structures, the bench height, the blast hole drill rig specifications, hole diameter, spacing and burden, explosive loading and initiation and blast size fragmentation. Productivity accounting is a methodology which is used elsewhere to give additional insights into the productivity and pricing factors that drive the financial performance of a business. Miners know intuitively that productivity and pricing influence costs and profit, but only with productivity accounting can the dollars involved be calculated. Drilling and blasting are part of a chain of unit operations in a mine. For an owner-miner, drilling and blasting would be considered as cost centres and a productivity accounting cost model approach would be relevant. On the other hand a contractor is likely to consider drilling and blasting as a profit centre, in which case a productivity accounting profit model approach would be appropriate. Both of these will be explained. The paper provides a basic outline of deterministic productivity accounting and demonstrates its application to blasting. Drilling and blasting data from a mine was obtained for a two-month period. The change in productivity and prices was calculated to obtain the dollar contributions from them towards the change in cost. It was determined that although there had been productivity dollar gains these were offset by larger pricing dollar losses, the net effect being that total drilling and blasting costs increased. The productivity accounting analysis gives the facts and the mine is in a position to establish priorities based on knowing the dollar contributions of each input used.

Jan 1, 2001

By O Kirtel, A A. Faizan

With the rapid increase and development of high-speed trains (HSTs), the problems such as train-induced ground vibration and its dynamic effects on nearby structures have become a major environmental concern in urban areas. Ground-born vibrations produced by high-speed trains pose a great challenge for engineers to build structures in such areas that is applicable for residents. In order to study the effect of train-induced ground vibration on nearby buildings, an advanced three-dimensional finite element model for train-induced ground vibrations has been developed using PLAXIS 3D Ultimate. The results of the in situ measurements which was previously carried out by the authors were used to validate the numerical model. The field test for ground vibration due to the passage of a high-speed train was carried out on the Istanbul-Ankara high-speed railway in Turkey with a train speed of 250 km/h. An in-depth analysis was achieved to investigate the effect of different soil properties on the train-induced ground vibrations by using the verified model. According to the result of the vibration analysis, the relative vibration response curves in all directions (x, y, z) for different soil conditions were obtained comparatively. The obtained results of the vibration analysis are discussed in order to figure out some useful conclusions.

Nov 29, 2022

By R W. Wilson, A R. Branch, T S. Pooe

The original bulk air cooling system at this particular mine made use of two water chilling refrigeration machines to produce peak cooling of approximately 12 MWR with a downcast air temperature of about 7°C; however, as the shaft is not used for transporting personnel, the opportunity existed to supply more cooling to the mine by lowering the downcast air temperature. An ice storage facility has been constructed and provides a range of opportunities in operating the system: colder air temperature sent to the shaft, enabled by using near-zero degree water produced by melting ice to cool the air; electricity time-of-use management, by shifting electricity usage out of peak tariff periods; and increased peak cooling capacity, by melting ice while chilling water. Ice is created in the storage facility at night while the ambient air temperature is low and then melted to produce cold water when required by the cooling process. An ice dam was constructed and serpentine stainless steel coils installed where the ice is produced; one of the refrigeration machines was converted to chill a glycol solution to subzero temperatures to create the ice on the coils; a plate heat exchanger was installed to allow the glycol chiller to act as a water chiller as well; and a third spray stage was added to the bulk air cooler to utilise the near-zero water. This paper describes the thermodynamic design, construction and performance assessment of the new system, which is unique, novel and represents the state-of-the-art of this type of cooling system and energy management.CITATION:Branch, A R, Wilson, R W and Pooe, T S, 2015. Novel use of ice thermal storage for energy management on a mine refrigeration plant, in Proceedings The Australian Mine Ventilation Conference, pp 185–192 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By R B. Wanty

Historically, most investigations of biogeochemical cycling in acid rock drainage systems involved synoptic sampling over longer time periods (one sample per week or month) or intensive time series studies over a few hours or days. However, many important episodic loading events, such as seasonal meltwater and storm events occur on timescales that are rarely observed by these traditional sampling approaches. Monitoring these transient processes, which may contribute the bulk of the annual metal loading, is essential for accurate assessment in acid rock drainage areas. Recent work also has demonstrated dramatic diel (24 hour cycle) variations in trace metal concentrations in response to diel changes in temperature, pH, oxygen, and photochemical cycling (Brick and Moore, 1996; Nimick et al, in prep). To characterise a system that may respond to diel, seasonal, and episodic events, a monitoring program must sample at a frequency that captures the details of these major forcing events. We developed two novel instruments, the Zn-DigiScan and the DigiSampler to examine low and high frequency temporal changes in acid rock drainage areas. The Zn-DigiScan is a battery powered real time in situ chemical analyser designed for long-term deployments with hourly analyses of Zn. Stream physical parameters (temperature, conductivity, dissolved oxygen, pH, turbidity, etc) were measured every 15 minutes with a water quality sonde. The DigiSampler was developed for the long-term daily sampling of biogeochemically active elements and can take either discrete samples or samples integrated over 24 hours. The DigiSampler collects 2 ml samples in a Teflon coil which are separated by 0.2 ml nitrogen bubbles. The sample coil is returned to lab and the 2 ml samples are diluted 1:10 and analysed for trace metals by ICP-MS. Initial results from a three-day deployment at Fisher Creek, MT, USA have successfully demonstrated the ability of the Zn-DigiScan to record Zn concentrations at levels below 100 ¦g/L. Zinc concentrations measured at 30 minute intervals in Fisher Creek showed a diel cycle with low values of ~25 ¦g/L in the late afternoon and increasing to ~60 ¦g/L by early morning. Zn concentrations were inversely related to temperature and pH, suggesting that temperature and pH dependent adsorption was the main factor controlling diel Zn fluctuations. Initial deployment of the DigiSampler also was successful, revealing diel cycles in Zn, Cu, and Mn. Comparison of trace metal samples collected by the DigiSampler showed good agreement with samples collected by an Isco automated water sampler, demonstrating that the DigiSampler can collect clean samples for trace metal analysis at the low ¦g/L range.

Jan 1, 2003

This paper refers to the open cut mining practice developed at Western Mining Corporation's Kalgoorlie Gold Operations (K.G.O.). Mining activity was centred attwo areas, namely W.M.C.'s Siberia "Sand King" and"Missouri" open cuts plus W.M.C.'s "Great Boulder" and K.M.A.'s "Horshoe" and "Morrison -Hannan's Star" open cuts in Fimiston.Kalgoorlie Gold Operations was set up initially to look after W.M.C.'s open cut interests in and about the Kalgoorlie area. The first mine commenced was, the Sand King open cut, approx 75 km NW of Kalgoorlie. it was here that the requirement for a highly selective form of mining first became apparent.

Jan 1, 1984

Projects to be undertaken in remote locations require special attention with regard to constructability from the very first stages of design. This is to ensure not only that the project is compatible with the environment in which it' is proposed to be built, but that it does not require facilities or special construction equipment and expertise that is not available in the proposed location. This paper draws on experiences gained on projects in Alaska, Northern Canada, South East Asia, outback Australia, and more recently Bougainville, in Papua New Guinea, where over the past 5 years Minenco has undertaken in excess of A$120 million of work on a number of different projects for Bougainville Copper Limited Although many of these projects have been close to large populous cities, which have been served by regular shipping and airline services, the locations have not had the availability of construction facilities which exist in major cities of Australia and thus can only be considered as remote locations by current day standards. As a result, every nut bolt and washer has had to be brought to the job site by the construction company. No hardware or electrical warehouses existed for those forgotten half dozen high tensile bolts, spring

Jan 1, 1986

By M S. El Salmawy

In order to develop the HF-free flotation reagent system, the main objective of this investigation was to study the possibility of separation of quartz from feldspar using non-ionic surfactants as the collector. The non-ionic surfactants used were polyoxyethyl cethyl ether (PECE) and polyethylene glycol monocethyl ether (PGME). The flotation behaviour of quartz and microcline with PECE and PGME was investigated. Each surfactant was a good selective collector for quartz with its recovery being influenced by pH and surfactant concentration. Quartz is floated favourably by both types of polyoxyethylene non-ionic surfactant whereas microcline was not so much. The floatability of quartz increases as the oxyethylene length of surfactants increases. Zeta potential measurements in the system of PGME/mineral were also carried out. It was determined that in the absence of PGME the points of zero charge for quartz and microcline should be approximately at pH 2.5 and 1.8, respectively. The addition of PGME to the system causes both minerals to become less negatively charged. Differences in the zeta potential value between quartz and microcline, in the presence of PGME, were detected. It can be suggested that the interaction of the oxyethylene group to the microcline surface should not be as strong as that to the quartz surface. In the mixed surfactant system of PGME and dodecylamine acetate (DAA), a small addition of DAA causes drastic enhancement of quartz flotation in the wide pH range of 1 ~ 10. In the mixed surfactant system selective flotation of quartz from microcline would be anticipated at pH

Jan 1, 2005

By A R. A Gomes

The Metropolitan Rapid Transit Authority (MRTA) Initial System Project (ISP) - Underground Structures North, UGN, is the northern section of the blue line, which is the first stage of an underground mass transport rail system of 77 km to be implemented in the central area of Bangkok, Thailand. The UGN section (Huai Kwang - Bang Sue) consists of approximately 8 km of twin single track bored tunnels, nine underground stations and some short cut and cover tunnel sections. The paper focuses on the main issues involved in the structural design of the precast concrete lining, which is the definitive structural support of the bored tunnels. It includes an overview of the site and geotechnical conditions, specific properties of precast concrete linings, ground-structure modelling, approach for the assessment of load conditions and respective sectional forces and particulars of the detailing of the reinforcement and the segment testing program.

Jan 1, 1999

Exploration of a coal deposit provides the data on which a range of mine plans can be developed during project feasibility. The stages of exploration use methods and procedures which initially outline the deposit with more detailed data gathering and analysis of the specific site complexities. The in situ coal resource and reserves are calculated. The mine plan is a function of the mining method chosen and can have significant impact on the recoverable reserves. Other factors which can impact on the recovery of the reserves and the ability to maintain planned production levels are those which were either undetected during exploration or were misinterpreted. Exploration programs should be detailed enough to minimise to an acceptable standard the recognised and potential risks. Past programs which explored to achieve a minimum exploration density required to satisfy measured reserve status have generally proven to be inadequate, placing reserves and production at risk.

Jan 1, 1997

Underground mines in Australia and worldwide are extending to greater depths. The effect of depth brings a number of challenges to mining engineers including geotechnical, ventilation, haulage and selection of mining method. The main effects of depth from a ventilation perspective are increased heat and humidity leading to reductions in productivity, occupational safety and health issues and the potential for fatalities. Numerous approaches have been undertaken over the years to mitigate against these effects. In this paper a review of various approaches to improving climatic conditions at a number of mine sites worldwide is undertaken. From these case studies it is argued that for mines at depth with the potential for a climate problem perhaps an alternative design philosophy to the established design philosophy should be utilised. In conclusion, the paper proposes some simple rules of thumb for use in mines with climate problems or the potential for climate problems.

Jan 1, 2008

By S H. Li, H Z. Gu, A Huang

High aluminium steel is a promising advanced steel known for its exception properties and holds significant economic and strategic importance. However, the CaO-Al2O3-SiO2 based slag with high alumina content reacts vigorously with alumina refractories during the smelting process at high temperature, seriously affecting the safe and efficient production of furnaces and resulting in the formation of Al2O3-MgO non-metallic inclusions within the molten steel. This is a bottleneck problem for high-quality steel refining, and the key reaction path during the corrosion remains unclear. The dissolution reaction mechanism of alumina refractories in high alumina CaO-Al2O3-SiO2 slags under a weak static magnetic field was investigated in this work, using high temperature laser confocal microscopy and in situ radiation spectroscopy techniques. The results indicate that the interaction between the high alumina slags and the alumina refractories is governed by free radical reactions. The dissolution of alumina forms AlO and AlO2 radicals. The reaction rate increases with the C/S ratio of the slag due to its low polymerisation. The reaction between non-bridging oxygen and AlO2 free radicals accelerates the generation of AlO and O2ꞏ- radicals. The reaction layer composed of calcium aluminate is formed through the recombination of AlO, Caꞏ+ and O2ꞏ- radicals. The weak static magnetic field induces the Zeeman splitting of free radical pairs and intersystem crossing occurs, promoting the formation of triplet free radical pairs through the hyper-fine coupling effect. The reaction can be significantly inhibited as the triplet free radical pair does not meet Pauli’s incompatibility principle. This discovery perfects the structure theory of molten slags with radicals and provides supplement to the design of the highly slag-resistant refractories, and provides the theoretical basis for the development of external field protection technologies for high-quality steel refining.

Jun 19, 2024

By H Masoumi, I Canbulat, Y Zhao, J Oh, H Lin

Borehole breakout is a drilling induced phenomenon caused by overstress of rock around the borehole. Its depth usually aligns with the minimum horizontal principal stress direction. For this reason, it has been used to determine stress orientations and a series of researchers also argued its dimensions can be indicative of stress magnitudes. If the stress dependencies of breakout geometries are well understood, it is possible to estimate stress magnitudes based on these data. This paper investigates the influences of critical parameters on breakout dimensions, including absolute stress magnitudes, stress ratios and borehole diameter. Several experiments have been conducted on cubic (120 x 120 x 120 mm3) sandstone samples with pre-drilled holes (22 mm and 30 mm) under true tri-axial loading conditions using UNSW self-designed equipment. Experimental results confirm the increasing maximum horizontal principal stress magnitudes result in larger angular span and longer breakout depth at constant minimum horizontal and vertical principal stresses. There is also a considerable discrepancy observed between experimental results and the analytical model. Findings of this study imply a potential on the estimation of stress magnitudes using borehole breakout. CITATION:Lin, H, Oh, J, Canbulat, I, Masoumi, H and Zhao, Y, 2018. Experimental investigation on borehole beakout and its implication on stress magnitudes, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 266–273 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By Yagi Y

The double track railway tunnel, called the Second Shirasaka Tunnel is being constructed under the supervision of Japanese PTational Rail- ways (JNR) in the tertiary soft rock strata in order to speed up the railway transportation. This tunnel (L=1765m), located in a central part of Japan, is excavated by the machine (roadheader), while the adjoining First Shirasaka Tunnel (L=1296m), completed five years ago, was driven by the blasting, and NATM is adopted in both tunnels. The geological features in this region are Neogene Tertiary of Miocene sediments consisted of mudstone, the sandy mudstone and the alter- ation of these rocks, having a squeezing be- haviour. And the geological structure is as complicated as some anticline and syncline structures, large or small scale exist, and as a lot of faults are found. The machine excavation manner using road- header is adopted in this tunnel to minimize the effect of excavation because there is a possibility of the occurrence of landslide due to the tunnel excavation, and also because local inhabitants reside on the ground surface.

Jan 1, 1987