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By F M. Senda

This paper highlights strategies used at the Barrick operated Kibali Gold Mine (KGM) to improve the drilling accuracy and blasting effectiveness for longhole open stoping. The mine currently uses Solo DL421 for the required stope drilling and has experienced an average deviation of 10 per cent. Strategies are raised to eliminate or at least mitigate the adverse effects of blasthole deviation and the impact of blasting induced effect at the stope faces including the stope crown. The integration of deviation trends in the design would allow the actual blastholes to be established within their required positions to then facilitate a proper energy distribution with the eventual production blasting. The implementation of stope undercutting reduces the hole length from 35 m to 30 m which in return decreases blasthole deviation by 3 per cent. Another strategy adopted to improve the drilling accuracy is to slow down the penetration rate with the use of several operating approaches, including 135 MPa percussion pressure, 65 rev/sec rotation speed and 17 MPa feed pressure. To this penetration rate, a constant k factor is applied to increase the rate when the bedding inclination is less than 45° from the horizontal or when the hole length is under 10 m. This reduces deviation by a further 4 per cent. Where the rock mass is highly jointed it is advised to use the average penetration rate over the entire length of the hole. Furthermore, the paper shows the effect of deviation on the blasting results through a prediction of fragmentation blasting model optimised with reduced deviation and highlights the effect of presplit mining and timing delay on the blasting effectiveness. Although the size pattern increases with deviation, a strategy pertaining to timing delay with blasting would be to align to the work of Grant (1990) where the optimum hole to hole delay is found to be between 7–10 ms/m of spacing, while the optimum delay between adjacent ring varied between 110–160 ms. Stabilisation of crowns and wings will perform with the implementation of presplit blasting.

Mar 29, 2023

By A Esfahanipour, M Osanloo

Determination of cut-off grade?strategy is one of the most important stages of open pit mine planning and design. It is the parameter directly influencing the financial, technical, economic, legal, environmental, social and political issues in relation to mining operation. Choosing the optimum cut-off grade strategy that maximises the economic outcome has been a major topic of research workers for nearly one century. Many researchers have contributed in devising methods and algorithms, such as dynamic programming, linear programming, optimal control and so on for various aspects of its determination. In this paper, a non-linear mathematical programming for cut-off grade strategy optimisation is presented, considering the three main stages of mining operation introduced by K F Lane. In this model maximisation of net present value of mining operation, under the three constraints of mining stagesÆ capacities, considered as the optimisation criteria. Due to the discrete representation of the mining resource, the proposed non-linear formulation is approximated by a non-linear signomial geometric programming. According to non-convexity and the complexity of the proposed model, an augmented Lagrangian genetic algorithm was used to find the optimum cut-off grade strategy under varying and fixed price circumstances. To validate the proposed non-linear model efficiency, the results were compared with the results obtained by the K F Lane methodology. It was found that the proposed non-linear model works efficiently in the determination of cut-off grade strategy. According to the simplicity of the structure of non-linear programming modelling in comparison with dynamic programming it is hoped that, further development of this model would certainly provide the ability of considering managerial and technical flexibilities as well as incorporating more real mining conditions in the determination of cut-off grade strategy optimisation.

Sep 26, 2011

By D K. Weatherley, G R. Ballantyne, S Ali, M Yahyaei, M S. Powell

This paper explores development of a novel ore characterisation method for the precise measurement of practical minimum comminution energy. A monolayer of particles with a narrow size distribution is broken using a precision rolls crusher (PRC); an ore characterisation device developed to overcome the shortcomings of conventional tests. For energy measurement, PRC uses two shaftmounted rotary torque transducers. These transducers acquire precise torque and angular speed data in response to the load applied to the rotating shafts during breakage events, which is converted into energy. The test progressively crushes feed particles down to final product size in many controlled breakage stages. The generation of fines in each breakage stage is then plotted as a function of input energy. The inverse of the gradient of this plot provides the size specific energy (SSE) in kWh/t of material generated below a predefined marker size; -75 μm in this case. The PRC has potential to evolve as a geometallurgical ore characterisation test—it is simple, fast, requires small sample mass (200–300 g), covers a wide feed particle size range (10 mm to 115 µm), and provides ideal SSE measurements that can be used for the calibration of on-site production equipment.

Aug 24, 2022

By Z Tong, M Gao, X Wang

In response to the need for improved magnetic separators for beneficiation of fine grained iron ores that have been finely ground to liberate the iron minerals from the gangue, a series of high efficiency wet drum permanent magnetic separators (T-GCT) has been developed by Maanshan Tiangong Technology Co Ltd. These magnetic separators have high efficiency for separating superfine strongly magnetic minerals and the ability to produce high-grade concentrates with high recovery. They are ideal replacements for conventional drum magnetic separators, especially for treating superfine particles.

Jan 1, 2009

By G M. Mudd

The growing popularity of platinum and platinum group metals (or PGMs, including palladium, rhodium and others) for a wide range of applications leads to some interesting issues for mining and sustainability. The uses for PGMs includes catalytic converters for air pollution control in vehicles, growing jewellery use, catalysts for various purposes (especially petroleum and chemicals processing), hydrogen fuel cells and many others. Given the growing importance of most of these PGM uses in more sustainable technologies or in making industrial processes more efficient, it is critical to understand the complex sustainability issues which surround platinum and PGMs. At present, South Africa is the dominant PGMs producer and holds about 88 per cent of estimated global resources, with important but relatively minor production and resources in Zimbabwe, Russia, Canada and the United States. Given the concentrated location of PGM resources, what are the likely trends in PGM mining with respect to environmental sustainability? That is, what are the costs in terms of energy, pollution, greenhouse gas emissions, water, land use impacts, social impacts, economic aspects associated with this globally important industry? This paper compiles and analyses a range of data on platinum-PGM mining, focusing primarily on South Africa. It synthesises a unique combination of data which relates typical production aspects such as ore grade and scale with sustainability aspects such as greenhouse, energy and water costs. The findings are critical in understanding the debate about the increasing environmental and social costs of some materials and technologies which are considered crucial for sustainable industries based on PGMs. Overall, the paper represents a valuable insight into the platinum-PGM sector, providing a range of useful data for understanding the environmental sustainability of this particular group of precious metals.

Jan 1, 2009

By W Patton, I Minniakhmetov, H Talebi, U Mueller

The sustainability of mining projects is linked to informed investment decisions based on public reporting of exploration and mineral resource estimation results. In Australia, public reporting guidelines are established by the Joint Ore Reserves Committee reporting code through the JORC Code (2012). Although the assessment of uncertainty in the results reported is a requirement, this is often communicated qualitatively and evaluated subjectively. This can become a liability particularly in the early stages of mining projects when spatial domains of geological interpretation and mineralisation envelopes inform resource estimations’ reliability. A recent review of JORC reports found no reports used quantitative assessments of the geological interpretation or mineral resource estimation envelopes, and 27 per cent of reports did not address the question of quality of geological interpretation. Reports that did address the quality used 19 different terms to communicate quality. This work presents methodologies for quantitative uncertainty assessment and communication and explores how they could be applied in public reporting practice. Quantitative uncertainty reporting would benefit mine planning and financial modelling as they normally assume the geology is 100 per cent right (since no error is reported or only a single deterministic model is provided). The complexity, cost, and additional work of doing a quantitative assessment could hinder a straightforward implementation. This could be overcome if mining companies budget for quantitative uncertainty assessment and associated professional development. A compulsory requirement for the inclusion of uncertainty assessments in public reporting or adopting standardised subjective language would improve industry practice.

Mar 22, 2022

By C Dick

Over the past three decades, mining operations have seen a significant increase in the use of contractors for mining, camp management and catering, recruitment, maintenance, power management, and commissioning. More recently contractors have been engaged for stores and logistics, OH&S, environmental, exploration, training etc. In some countries, such as South Africa, the trend is towards total outsourcing of all aspects of a mining operation which is coordinated by the owners’ management team.During the Global Financial Crisis (GFC) more Australian companies considered and/or took on this approach to recruiting for both projects and operations as mining companies were forced to rethink their corporate strategies as commodity prices plummeted to low levels, pushing operations and projects into potentially financially unviable territory.This paper discusses the labour recruitment, commissioning and operating strategy of Western Areas NL (WSA), with the assistance of Independent Metallurgical Operations Pty Ltd (IMO), as it progressed construction, commissioning and operation of the Cosmic Boy nickel concentrator at the Forrestania Nickel Project during and post GFC. The use of IMO contractors allowed Western Areas to mitigate labour cost risk during the uncertainty caused by the GFC and let their management team focus on the task of bringing a new operation into viable and profitable production.

Aug 8, 2011

By K G. Harding, A Osman, A du Toit, F K. Crundwell, C M. Sheridan

"Most mineral processing plants have high water requirements for their operational activities. These plants often function in an environment where water is becoming increasingly scarce. An increase in population will result in an increased demand for water; potentially beyond the limits of supply and hence increased competition for the resource. In South Africa, Gauteng and the North West Province are likely to be first to experience a shortage of potable water.In order to avoid a water crisis, efforts must be made to ensure the effective management of water resources and the minimisation of wastage. Hydrometallurgical plants have a responsibility to society and the environment to operate in a sustainable manner - reducing their water requirements will certainly assist towards developing a sustainable footprint.This project improved site water management by: surveying the potable water and storm water systems with a view to assessing the current water accountability and determining methods to improve accountability determining the monthly and yearly water balance for the site and presenting it in the form of a water balance sheet drawing up an input-output and operational model in accordance with the Minerals Council of AustraliaÆs æWater Accounting Framework for the Minerals IndustryÆ calculating the water footprints of the refinery identifying ways in which water savings could be achieved recommending management systems for water usage monitoring.This work was conducted in South Africa. The value of this work lies in that it established the current baseline and assisted in developing management systems that can reduce water usage sustainably.CITATION:Osman, A, Crundwell, F K, Harding, K G, Sheridan, C M and du Toit, A, 2013. Water accountability and efficiency at a base metals refinery, in Proceedings Water in Mining 2013, pp 277-286 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

By E N. Sparg, O D. A Deuchar, F Needham

Decline shafts are an attractive option to both new and existing mining operations where there is a need to access an inclined orebody deposit via on-reef development so as to generate a return in the shortest possible time. There are many different technologies that are available to transport men, material and rock in incline shafts. This paper focuses on the applicability of two hoisting technologies for decline shafts, namely endless and direct rope systems. The pros and cons of each system are reviewed. A common concern with direct rope haulage systems is the possibility of generating slack rope during deceleration. This paper illustrates the issues involved in designing a system so as to avoid the possibility of slack rope. In conclusion, the key factors relevant to the selection of endless or direct rope haulages for a particular decline application are reviewed. The paper is a joint submission by FFE Minerals-Vecor and Qualter Hall UK.

Jan 1, 2005

By M Davies, G Theletsane, A H. Gray

Recovery of gold from gold ores has been driven by the available technology and its configuration in the process plant flow sheet.Conventional practice in test work programs has the ore being ground fine (to 106 or 75 microns) to ensure liberation ahead of leaching or flotation. This paper identifies that, in many cases, gold and gold sulfide carriers will liberate and be recovered to a concentrate at much coarser sizes.There is an exponential increase in energy consumption relative to particle size reduction. This impact becomes extreme when comparing crushing a product to 1 mm against grinding to 75?microns.The resultant reduction in energy consumption when liberating and separating at 1 mm or coarser compared to grinding to 75 microns can be in the order of 15 kWh/t or 60 per cent of energy in the comminution circuit.Recovery of free gold and gold sulfide carriers by preconcentration (using continuous gravity devices such as the InLine Pressure Jig), combined with flotation of the fine gold and gold carriers, can result in significant power savings.There are multiple locations within the flow sheet that can be targeted using this process, including recovery in the cyclone underflow of existing plants, preconcentration ahead of the plant or complete greenfield, low-energy process plants designed from first principles based on data from a Gekko developed test work regime.We will describe the process of defining mineralogy in the laboratory and the decision-making process through to actual applications in the field.Several examples will be provided, including a South African Witwatersrand gold ore, several Australian gold ores and others, indicating the benefits of this process and where it has been brought to commercial reality.CITATION:Gray, A H, Davies, M and Theletsane, G, 2014. Coarse liberation and recovery of free gold and gold sulfide carriers for energy reduction in process plants, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 117–128 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By J Edman, RáBeamish, G Cambourn, B Beamish

Moist Adiabatic Benchmark (MAB) and R70 testing have been applied to core samples of a multiple seam sequence from a borehole at the Doyles Creek Project. The coal samples range in rank from high volatile B bituminous to high volatile A bituminous, with a general increase in coal rank as depth increases in the borehole. The intrinsic coal reactivity to oxygen decreases with coal rank as indicated by the R70 values. The time taken to reach thermal runaway shown by the MAB testing however is strongly modified by the interaction between the intrinsic coal reactivity, the moisture content of the coal and the retained gas content of the coal. This is clearly demonstrated by the lowermost seam of the sequence. The MAB test for coal from the Whynot Seam took 20 days to go to thermal runaway, which projects to heating issues taking between eight to 12 months to occur for loosely piled coal found in coal roof falls or a longwall goaf and uncompacted stockpiles, assuming sufficient air is available for coal oxidation. The results from this project illustrate leading practice for the operational planning and development of an appropriate spontaneous combustion management plan (SCMP).CITATION:Beamish, B, Cambourn, G, Lewis, G, Edman, J and Beamish, R, 2013. Application of leading practice spontaneous combustion assessment to exploration at the Doyles Creek Project, in Proceedings The Australian Mine Ventilation Conference , pp 293-298 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By M Armony, J F. C L Costa, J C. Koppe

Linear kriging methods fail to estimate local grades and local reserves for highly skewed variables due to three reasons: it uses only part of the available data information, it has no physical principles associated with the mathematical proceedings to minimise the problems, and it works with continuous variables while data are discrete because of the limited precision of any equipment. The techniques commonly used up to now to solve the highly skewed variables estimation problems were unsuccessful, unless mathematical rigor is abandoned. Even the method of multiple indicator kriging is not satisfactory. This paper presents a new framework, the field parametric geostatistics (FPG) that transforms noisy variograms into well-behaved variograms and justifies mathematically empirical procedures commonly used, as trimming or capping arbitrarily very high values. The method, when applied to non-skewed variables, yields similar results to classic kriging. The methodology is illustrated in a case study at a gold deposit in Brazil, and compared to results obtained by usual techniques.

Sep 26, 2011

By J Rubio

This work presents design features of an innovative in-line mixing helical (coiled) reactor for flocculation and flotation as a solid-liquid separation process for suspended particles (including liquid droplets). The device has been named flocs generator reactor (FGR), a compact system whereby the flocculation of particles is assisted by the kinetic energy transfer from the hydraulic flow through the reactor and/or by the injection of microbubbles (30 - 70 ¦m). The flow mixing presented a plug flow regime with a low dispersion degree, promoting the required hydrodynamic conditions to disperse the polymer flocculant (cationic polyacrylamide) and to generate æstrongÆ flocs of Fe(OH)3 or clays (as colloidal model systems) with aggregation using an anionic polymer, Al2(SO4)3 and poly aluminium chloride (PAC), and oil emulsions destabilisation with a high molecular weight cationic polymer. The solid-liquid separation of the flocs was then achieved either by settling or by flotation with microbubbles. This paper discusses advances in this new in-line flocculation-rapid flotation device to remove æaerated aggregatesÆ, aggregates with entrained and entrapped bubbles. Studies were carried out with different models of FGRs (varying the length:volume ratio) and process efficiency (mainly kinetics) evaluated as a function of polymer concentration and some operating parameters, namely, feed flow-rate, air:solids ratio and residence time. Results showed that the aerated flocs are readily floated with rising rates in the order of 120 mh-1, values higher than those obtained for the settling of the non-aerated flocs (18 - 24 mh-1). The FGR requires short residence times and generates dense, well structured flocs (with a mass fractal dimension, dF of about three) which withstand high shear forces. Mechanisms involved appear to include small bubble formation and their rapid occlusion (entrapment) within flocs, nucleation of bubbles at floc/water interfaces, polymer coiling as a result of æsalting outÆ effects at the aqueous/air interface and plug flow type of mixing (flocculation). Successful examples of emulsified oil and solids removal from water are shown and because in all cases high efficiencies were obtained (>90 per cent removal). Due to the high process efficiency and high loading capacity shown, the FGR appears to have good potential as an in-line flotation-separator device in applications requiring high rate solid-liquid or liquid-liquid separations.

Jan 1, 2005

By D Engelhardt, G Lane

The Cadia mine has shifted from an open pit operation to the Cadia East underground panel cave. The resulting increase in milled tonnes, more competent ore and the decrease in fines production through shifting to panel caving were predicted to require an increase of over 25 per cent in installed power. This expansion was accomplished via the installation of secondary and high pressure grinding rolls (HPGR) crushing of the ore, with the semi-autogenous grinding (SAG) mill receiving a combination of primary, secondary and HPGR crushed feed. This design, criteria and rationale for selection was presented at the SAG Conference 2011. This paper reports on the initial impact of secondary and HPGR crushing on the circuit performance with the new panel cave feed.CITATION:Engelhardt, D, Lane, G and Powell, M S, 2014. Cadia expansion – the impact of installing high pressure grinding rolls prior to a semi-autogenous grinding mill, in Proceedings 12th AusIMM Mill Operators’ Conference 2014 , pp 233–240 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 1, 2014

By B Reynolds

The process design for green- or brown-fields metallurgical plants typically starts with two fundamental elements: the detailed mass and energy balance and the plant flow availability. The detailed mass and energy balance is generally developed using process flow-sheet simulation software and represents the steady-state operation of the plant at normal operating conditions. The plant flow availability, also known as a range of other industry-specific terms such as ‘flow availability’ and ‘operating factor’, describes the ratio of plant production to the steady-state mass balance. These elements are then used together as the basis for equipment selection and design.Plant flow availability takes into account a myriad of production loss factors including planned and breakdown maintenance, feed availability and composition changes, variability in operational performance and the interaction of batch and continuous unit operations. The combined impact of these loss factors are complex and as such plant flow availability is usually derived using a top-down approach such as comparison to an existing operation, a group of similar operations or to an anecdotal ‘industry leading’ benchmark. These top-down approaches are fraught with risk however, as they cannot factor in changes to equipment selection, flow-sheet or plant operating philosophy, and can result in over-expenditure of scarce capital or shortfalls in plant production.The use of dynamic simulation to provide a bottom-up alternative to quantifying the plant flow availability in metallurgical plant design has been growing rapidly in recent years. It provides a technique to quantify the combined impact of the loss factors described here and a tool to support process design and equipment selection by facilitating a range of sensitivity and what-if analyses. This paper presents a case study of how dynamic simulation has recently been used to support the

Aug 8, 2011

By E Niva

The IsaMillÖ is challenging the way that plants are designed and operated. This paper challenges existing designs of concentrator flow sheets, particularly focusing on magnetite circuits.   From what has started out as a small scale ultra fine grinding mill in the pharmaceutical and pigment industries, it has been redesigned and improved upon for mineral processing, and has been the mainstay of fine grinding applications for over ten years. These applications have required energy efficient grinding to succeed, and have been predominately in the base metals industry.   Further development of the IsaMillÖ has now resulted in the machines being able to treat larger tonnages, with higher capacity motors. This development, along with the introduction of purpose designed ceramic media, has allowed the mill to treat courser feed sizes. At the same time, the mill still offers highly efficient grinding, and has enabled it to be operated in coarser tertiary and secondary grinding applications.   The acceptance of the mill in coarser applications, predominately in base metals and PGM applications, has enabled the IsaMillÖ to be a serious contender for beneficiation in other minerals. One such application is the potential for IsaMillsÖ to be part of magnetite flow sheets, which are being considered in Australia to meet the growing iron demand of China. The high energy efficiency of the IsaMillÖ compared to conventional technologies, as well as the smaller infrastructure requirements, provides a great opportunity to reduce the power intensity of magnetite circuits.   This paper will examine the use of IsaMillÖ technology in conventional grinding applications, including recent testwork in a primary grinding base metal circuit, as well as testwork on magnetite ore comparing a lab scale IsaMillÖ with a lab scale Tower Mill.   The growing demand for minerals over the next decade, coupled with higher energy cost, will result in energy efficient technology, such as the IsaMillÖ, being included in standard circuit design.

Jan 1, 2008

By H Weitz

Bateman Engineering provided process technology and engineering design to China Yunnan Metallurgical Company (CYMCO) for a 30 MW DC furnace for the production of high-grade titanium dioxide slag.Following the successful commissioning of the furnace during the latter part of 2009 and the first quarter of 2010, a period of adverse circumstances resulted in having to operate the furnace without feed and at a low power input for a period of time. When normal feed resumed, a layer of solid material was detected on the slag-iron interface during sounding measurements. The condition of the iron was also significantly altered. The iron temperature was much higher than the design value, but the carbon content had decreased to such an extent that a large amount of iron solidified in the furnace, which made iron tapping very challenging. The slag temperature was increased in order to melt the solidified iron. However, severe sidewall damage resulted, which finally led to a burn-through. A number of samples were taken from the slag that remained in the furnace. These samples were analysed to determine the chemistry and phase profile throughout the slag bath. The mechanisms of formation of the high melting-temperature phase on the slag-iron interface are discussed, as well as procedures that can be applied to prevent a recurrence of this phenomenon. Some recommendations are made for instances when furnace feeding is interrupted for an indeterminate period.

Oct 5, 2011

By A Tang, K Ringwood

"Water is increasingly being recognised as a material business risk that many companies are still not well-equipped to deal with. Despite a raft of water-risk focused initiatives, methodologies and guidelines, the challenge of managing the strong link between the technical and operational water issues, along with the growing external challenges and interests in water, remain a significant risk to a companyÆs ability to deliver value.This paper provides an overview of the key lessons learnt from ERMÆs experience of working with companies across a range of water sensitive industry sectors, in particular, the mining and oil and gas sectors, to develop and implement practical approaches to manage business critical water risk. These examples highlight the importance of managing water risk by linking technical and operational aspects of water management - with the longer term strategic and social license aspects. Four key ingredients were identified that are central to providing companies with a leading edge in the successful mitigation of water risk: understanding and evaluating water risk including the technical and operational aspects of water management, plus the longer term strategic and social aspects articulating a strong business case that prioritises water risks and their financial exposure to the organisation constructing a clear roadmap that practically links the water strategy objectives with on-the-ground implementation and action building capacity in the organisation to manage, engage and coordinate on water to mitigate risk.CITATION:Ringwood, K and Tang, A, 2013. Practical approaches to managing business critical water risk, in Proceedings Water in Mining 2013, pp 293-300 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 26, 2013

By Y Potvin

Underground mines in Australia are progressively operating at greater depth, sometimes in conditions where mine induced stresses are very high. In such conditions, the seismic activity often becomes intense and violent and in response, mines must develop and implement a sound rock burst risk management strategy to continue operating safely.This paper discusses the latest techniques successfully used in Australian mines to mitigate the risk of rock bursts. In particular, the paper describes how the analysis of data collected from seismic monitoring systems can provide an understanding of the seismicity and be used for quantifying seismic hazards in the mine. Once an adequate understanding and assessment of seismic hazard has been achieved, the associated risk can be mitigated using different layers of protection.Strategically, modifying the mining method, the extraction sequence and/or the mining layout can alleviate the seismic hazard, but these solutions generally cannot be implemented rapidly. In the short-term, seismic risk can be mitigated tactically using an energy absorbing support system or to remove personnel from being exposed to rock burst damage by implementing exclusion zones.

Mar 21, 2011

By J W. Muir, N Bedford

Hong Kong is one of the most rapidly developing cities in the world. With constant population growth and limited opportunities for space, the development of a fast and effective underground public transportation network is essential. Hong Kong’s Mass Transit Railway (MTR) Corporation is currently undertaking several large underground expansions to its existing network. Much of the excavation will be carried out using the drill and blast excavation method.Drill and blast excavation is common in Hong Kong and with the continued development of underground infrastructure the use of the drill and blast excavation method will increase. Although an effective method of excavation, the blasting vibrations caused during construction can have an adverse impact on surrounding structures and impose disruption on the local community.In order to minimise the risks associated with blasting vibrations, and to demonstrate that the impact on local stakeholders will remain within acceptable limits, it is generally necessary for a contractor to submit a blasting assessment report for approval by government authorities before blasting may commence.Continued increases in population density will force more infrastructure to be constructed underground. Tunnels and caverns are increasingly excavated in closer proximity to critical sensitive receivers. This leads to greater potential impacts on the community, tightening constraints on contractors and a higher level of confidence required for approval authorities. Finding a balance between the needs of the community and rising construction costs becomes more challenging.This paper presents a case study on how the blasting assessment report process has been successfully implemented for a major MTR project situated in a densely developed area of Hong Kong. It describes several methods of assessing blasting vibration impacts, innovative uses of blasting for excavation and the mitigation measures employed to provide the best outcome for all project stakeholders.CITATION:Bedford, N and Muir, J W, 2014. Blasting vibration assessment and innovative blasting methods in high-density urban environments, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 9–20 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014