Search Documents

By I Onederra

A better understanding of the detonation performance of an explosive charge can be gained by directly measuring pressure, temperature and velocity of detonation (VOD). This is particularly important with explosives used in the mining industry because their performance is directly influenced by the degree of confinement given by the borehole diameter and the surrounding rock mass. A project funded by the Australian Coal Association Research Program (ACARP) was initiated in early 2009 with the view to design and build cost-effective prototype instrumentation to measure the relative differences in detonation pressures and temperatures of commercial mining explosives. The project’s primary focus was on low-density explosives. Low-density (also referred to as low shock) explosives have been available in various forms for nearly 20 years. There have been significant advances in the availability, reliability and flexibility of these explosives, which now offer a range of densities and degrees of water resistance. Their detonation performance is not well understood and cannot be accurately predicted with current ideal and non-ideal detonation codes. It was therefore viewed as important to be able to directly measure pressure and temperature during the detonation process of these complex mixtures in production blastholes. Identifying the pressure release patterns of both conventional and low-density explosives under different geotechnical conditions should provide the necessary information to both validate detonation codes and better define input parameters for breakage and fragmentation models. This paper gives a general description of the prototype instrumentation developed and reports on the results obtained to date in full-scale conditions.

Nov 8, 2011

By D Flint, O Rindriatmoko

PT FreeportÆs Deep Ore Zone (DOZ) Mine is the latest block cave mine within the East Ertsberg Skarn System (EESS).Issues with undercutting and stress concentrations at the extraction level were experienced, leading to reduced pillar strength.The extraction level-related issues became more pronounced, leading to local panel drift collapse, in an area that was over 100 per cent extraction. A review of ground conditions, panel collapse descriptions, and factors contributing to panel collapse are presented in this paper.

Jan 1, 2005

By J W Shields

The aim of this paper is to present a concept or model regarding a particular geological environment where gold orebodies occur in the Pine Creek Geosyncline and indeed in many other pans of the world. The name GIGIACS (an acronym for Gold In Greywacke In Anticlinal CrestS) is proposed to label this concept or model. The name Saddle Reefs (which has been in use for many years) is used for gold-bearing quartz veins which often occur in conjunction with Gigiacs. Simple patterns formed by this type of mineralisation at the surface due to different configurations are illustrated. Some examples of Gigiacs and associated saddle reefs are presented from the Pine Creek Geosyncline together with examples from other parts of the world. This concept has been used successfully as an exploration tool and five examples are given. The terms Gicsiacs (for Gold In Carbonaceous Shale In Anticlinal CrestS) and Giliacs (for Gold In Limestone In Anticlinal CrestS) are also used.

Jan 1, 1994

By S Kodate, Ö Aydan, Y Suda, J Tomiyama

Fracture zones are commonly found in the Earth’s crust. These zones may cause very severe engineering problems. Therefore, the formation and the assessment of the mechanical characteristics of these zones is of great concern for rock engineers. A new double shearing jig was used to study the formation of shear zones in rock under static and impact loading conditions using the device developed by the authors. A series of experiments were undertaken to investigate formation on the formation and characteristics of fracture zones in laboratory. Although actual fracture zones are more complicated, various tests give some insight view of the formation of fracture zones as well as some information on their mechanical behaviour under both dynamic conditions and static conditions. The authors report the outcomes of these experiments and discuss their implications in practice.

Nov 29, 2022

By A M. Lechner, S Arnold, M J. Gillespie, P D. Erskine, D R. Mulligan, A T. Fletcher, A Gordon

Mine ecological monitoring schemes are often conducted only to address compliance and in some cases do not have the sufficient statistical power or understanding of ecological systems to assess, quantitatively, the meeting of rehabilitation targets or mine impacts. Monitoring schemes for rehabilitation commonly rely on analogue sites or premining baselines (reference sites) to assess whether rehabilitation sites are ecologically similar and thus successfully rehabilitated. In the case of monitoring for mine impacts, if the impacted sites diverge from reference data, the site is considered to be impacted. Fundamental to any monitoring scheme is testing the sampling design to ensure that it can detect these differences if they are present through adequate sample sizes (ie statistical power). However, a good understanding of the ecological system is required to ensure that differences detected are ecologically significant. Modelling ecosystem properties can provide a quantitative understanding of how ecosystems change over time and space, in response to natural environmental variations and thus aid in determining significant ecological differences. Furthermore, modelling methods can be used to predict future ecosystem states. Within the ecological literature, guidelines for robust statistical monitoring designs and modelling methods exist but are not routinely being used in the mining industry. This paper uses simple examples to discuss: problems with current compliance monitoring methods; importance of robust statistical techniques; and how modelling can assist rehabilitation assessment and guide monitoring schemes. The aim of this paper is to describe general monitoring and modelling methods that could be potentially used for mine site monitoring and closure assessment. These methods are often considered by mining companies as an extra expense that provide little practical benefit, and the domain of academia; however, engaging these methods may be more cost-effective in the long-run than conducting untargeted monitoring schemes that give no confidence to regulators on whether rehabilitation criteria have been met. Furthermore, monitoring programs in mining contexts provide a good opportunity to better understand long-term ecological patterns and test the application of more rigorous modelling approaches as the life of many mines tends to be greater than ten years.CITATION:Lechner, A M, Arnold, S, Fletcher, A T, Gordon, A, Erskine, P D, Gillespie, M J and Mulligan, D R, 2012. Embracing modern ecological methods - Monitoring and modelling for mine closure, not compliance, in Proceedings Life-of-Mine 2012 , pp 25-32 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By Y Li, Z Fu, D J. Williams, E Topal

Mine waste rock is unavoidable in the recovery of ore by open pit mining methods. Effective management of waste rock movement covers the removal and placement of the waste rock, generally in a surface dump in the most cost-effective way while satisfying the long-term environmental expectations. Since the 1960s, there has been significant research carried out into planning of ore movement from open pit mines such that the overall net present value (NPV) of the project can be maximised. Currently, several software packages are available to achieve this task as a common practice within the mining industry. However, planning of mine waste rock movement is still achieved manually, as the available software does not consider optimal waste rock movement and dump design. This paper describes a tool to optimise waste rock placement, which minimises the haulage cost while creating environmentally friendly waste rock dumps through selective placement and encapsulation of the reactive waste rock in the dump. The embedded methodology in this tool has been developed based on the mixed integer programming (MIP) modelling technique to optimise the waste rock movement. The methodology provides an easily-manipulated and fully-automatic tool for professionals to complete waste rock dump scheduling in four main steps: data input, model construction, model computation and solution retrieval. The application of the new tool into a real case project in this paper shows that it can determine economically and environmentally optimised waste rock dump schedules in an acceptable time frame.CITATION:Fu, Z, Li, Y, Topal, E and Williams, D J, 2015. A new tool for optimisation of mine waste management in potential acid forming conditions, in Proceedings Tailings and Mine Waste Management for the 21st Century, pp 333–342 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By T Baumgartl, T Huynh, K Tungpalan, E Wightman, M Edraki, M Tayebi-Khorami, L Huang, S Palaniandy, E Manlapig

With the increasing rate of tailing production worldwide there is a growing concern about the hazards of tailings storage facilities (TSF). Past and current mining, processing and waste disposal strategies that focus on the extraction of the valuable minerals, and an economic assessment only, are no longer suitable. Social implications and environmental legacies must be included for effective evaluation. This is possible by using an integrated assessment framework to evaluate more alternatives, including the production of additional saleable and benign streams, alternative tailings treatment and disposal as well as options for reuse, recycling and preprocessing of existing tailings. Tailings are not viewed as a final waste product but as part of the resource. From the sustainability perspective the models developed in integrated research programs will contribute to more effective methods for assessing different scenarios and potential processes and lead to better environmental management, increased production of benign tailings and improved efficiency of water and energy use and thus more responsible resource stewardship of the ore resource.This paper presents preliminary results from a multiyear research program on integrated tailings management at the Sustainable Minerals Institute (SMI), The University of Queensland, called ‘Designer Tailings’. The project involves the gathering of experimental and observational information on tailings biogeochemical processes to design and modify the range of activities within mineral processing plants, upstream characterisation ore and gangue, and downstream tailings management for desired tailings properties and outcomes. This information will assist the development of new total integrated value chain CITATION:Edraki, M, Huynh, T, Baumgartl, T, Huang, L, Andrusiewicz, M, Tungpalan, K, Tayebi-Khorami, M, Wightman, E, Palaniandy, S, Manlapig, E, Evans, C, Farrokhpay, S, Bradshaw, D and Vink, S, 2014. Designer tailings – an integrated model for tailings management, in Proceedings Life-of-Mine 2014 , pp 599–608 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By J-P Franzidis, M Esvelt, E V. Manla

The Floatability Characterisation Test Rig (FCTR) is a self-contained, highly instrumented, mobile pilot plant that is able to treat up to 2 tph solids. It consists of a bank of six 130 L WEMCO« SmartCells« and a bank of six 50 L WEMCO« SmartCells«. It was developed as part of the AMIRA P9 Project, primarily to determine ore floatability characteristics and to develop and validate flotation plant modelling, scale-up and simulation methodologies. However, it may also be used to carry out pilot-scale flotation test work. This paper briefly describes the circuit modelling, simulation and scale-up test work performed using the FCTR and the use of the FCTR in pilot-plant test work performed by the metallurgical staff at WMCÆs Kambalda Nickel Operations and Mount Keith Nickel Operation. At both Kambalda and Mount Keith the FCTR was found to be very flexible and straightforward to run, with an easily changeable circuit configuration and stable operation. Testwork was facilitated through having full stream sampling on all streams, and a high degree of instrumentation providing accurate measurement of process variables. The results obtained from the FCTR testwork were highly repeatable. As a consequence of using the FCTR, WMCÆs Kambalda Operation and Mt Keith Operation were able to complete a rigorous programme of pilot plant testwork more quickly than in the past, and with a high degree of confidence in the results.

Jan 1, 2003

By C D. Rose

A review and summary of the results of 120 coal sampling system bias tests is presented. This review supports new methodology using multivariate statistics currently being considered by ISO TC27 SC4. The current difficulties with ISO 13909-8 are explained and the logic behind the current new working draft is discussed in detail. Bias was detected in nearly 36 per cent of tests reviewed, suggesting that much improvement is needed in designing, maintaining and monitoring the performance of sampling systems in order to avoid sampling bias.CITATION:Rose, C D, 2012. Bias testing of mechanical sampling systems for coal - A review of test results and call for use of multivariate statistical analyses, in Proceedings Sampling 2012 , pp 185-192 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By H Thanasekaran, M J. Mankosa, J N. Kohmuench, G H. Luttrell

"Fluidised-bed flotation has been demonstrated over the last 16 years as an effective method for improving the flotation recovery of coarse particles. This technology has been successfully deployed into the industrial mineral sector with multiple installations within phosphate beneficiation plants and potash mills. Due to the minimal mineral surface expression required when utilising this technology, more recent studies have centred on the applicability of using this HydroFloat™ technology for the recovery of coarse sulfides and base metals. Multiple approaches have been investigated to determine the best means for implementing this novel coarse particle flotation system into both existing and new plant circuitry. These include the treatment of tailings to recover values that have been lost using conventional technologies and also the direct treatment of a coarse feed, either within the grinding circuit or by use of a separate split-feed flotation approach. Recent applications of the technology will be presented along with data generated from several test campaigns and ongoing research investigations. The benefits of properly applying this technology, such as reduced power consumption and increased mill capacity will be discussed.Citation:Kohmuench, J N, Thanasekaran, H, Mankosa, M J and Luttrell, G H, 2016. The Impact of Fluidised-bed Flotation for Treating Coarse Sulfides, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 105–112 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By J Joy, A Bye, G V. Kizil

This paper demonstrates an application of a recently developed Risk-Cost-Benefit (RCB) Framework to environmental risk management in the mining industry. The environmental application of the RCB Framework as part of an ACARP project (Kizil, Bye and Joy, 2012) involved a thorough selection process with site visits and in-depth discussions with the case study siteÆs environmental management team. Under their guidance, the highest risk of environmental impact at the case study site was identified as æroad subsidenceÆ at the time when the project work was undertaken. This paper presents the unique application of the RCB Framework to examine the risk of mining-induced subsidence and its impact on one of AustraliaÆs busiest highways, with a traffic volume of 38 000 vehicles per day (NSW RTA AADT, 2008). The RCB Framework was employed to assess the optimum group of controls for road subsidence risk management to ensure highway availability while mining occurs. Whilst this paper focuses on road subsidence, the methodology employed can be directly applied to other environmental concerns including preparation for mine closure, rehabilitation planning and waste management. The RCB Framework incorporates mathematical modules which were developed to enable complex yet tightly integrated RCB calculations. The process integrates the risk-control effectiveness assessment to determine that the selected safety initiative is financially beneficial to the mine site and company. This concept has been applied to a number of high-risk mining areas targeting safety, productivity and environmental issues. This paper introduces the five-staged RCB Framework, incorporating the RCB tools RCBGEN (Risk-Cost-Benefit Generator) and RCEMETHOD (Risk-Control-Effectiveness Method), and demonstrates its practical application to the risk management of a road subsidence case study. The case study looks at potential pavement damages, in particular, the occurrence of pavement stepping on the surface of the highway as a result of vertical subsidence. This type of road damage was previously experienced at another major inter-city route while underground mining occurred in the region where the case study site is located. The RCB Framework has been successfully applied to the analysis of the road subsidence case study and determined the risk reduction and financial benefits of implementing a range of risk-controls. User-friendly RCB Charts to provide an aid for decision-making were produced. The value of using the RCB charts to achieve balance between risk, cost and productivity in the decision-making process for risk management has been explained. The case study determined that pavement slots and fibre-optic cable monitoring were relatively low-cost and effective controls applied in the mining industry for the first time at a global level.This paper supports the industryÆs ongoing efforts to manage risk to ALARP (as low as reasonably practicable) and achieve æzero harmÆ by providing a new Framework to more effectively establish the adequacy of controls.CITATION:Kizil, G V, Bye, A and Joy, J, 2012. Application of risk-cost-benefit analysis to highway subsidence due to mining, in Proceedings Life-of-Mine 2012 , pp 197-206 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By A G McLean

This paper will first discuss the fundamental requirements for reliable discharge of backfill by gravity alone at high per cent solids. This discussion will include brief mention of the underlying principles of saturated solids flow contrasted to that of stirred tank or dilute discharge systems. Here the need to possess full knowledge of the flow properties of the stored material will be highlighted. In regard to attainment of reliable discharge it will he revealed flow from a backfill silo will only occur provided: ò the flowing material in the converging channel is yielding throughout; ò slip is occurring along the walls; ò an arched stress field is present in the vicinity of the outlet; ò the flowing backfill must be dilating to flow in response to the dilating stress field; ò sufficient dilation water is injected, in the hopper, to eliminate the formation of adverse interstitial pressure gradients; ò sufficient dilution water is injected, downstream from the hopper outlet, to generate a pumpable slurry of maximum per cent solids; ò the silo level must be sufficient to prevent the pump suction forming a rathole; ò the system must be configured and operated to generate stable discharge density; and ò the system must be configured and operated to minimise damage to the pump liners. In addition proper account must be made of the silo overflow weir and settling capacity to match plant throughput. Here opportunity will be taken to highlight the complexity of this multi-phase flow situation as well as the general yet paramount requirements for reliable solids flow. It will be shown that by proper attention to the multi-phase considerations gravity discharge of slurries as a consolidated bed with minimal water content is possible. Such high solids discharge results in greatly reduced demand for process water. In addition pumping costs are reduced as is the delay time associated with the mine drainage operation. Confirmation of successful applications will be highlighted by reference to several recent case studies. In the concluding phase mention will be made of the key yet very simple and effective operation techniques which enhance reliable Discharge.

Jan 1, 1998

By D Davis

The prediction of ground-borne noise levels from tunnel construction activities requires knowledge of the input vibration forces from the vibration source(s) into the cutting face, knowledge of the vibration transmissibility through the surrounding medium, and knowledge of the receiver building’s vibro-acoustic response. The conversion of this vibration energy into sound pressure within the receiver building depends upon the vibration coupling of the soil and the building’s foundations, the structure’s response including floor-to-floor attenuation and amplifi cation due to resonance, the radiation effi ciencies of the internal structural elements, and the room’s acoustical properties. Beginning with a known input vibration spectrum at the cutting face, it is possible to predict the resultant ground-borne noise levels within a receiver building using either analytical and/or empirical techniques, or by numerical modelling. This paper presents an overview of the various methods available to estimate ground-borne noise levels from tunnel construction activities and discusses the advantages and limitations of each.

Mar 8, 2011

By M Bouare, C Holland, K N’Diaye

Two adjacent open pits in Mali hosted by deeply weathered saprolitic materials were mined consecutively over the course of approximately 12 months. During excavation, both pits experienced significant displacement and tension cracking as the result of deeper than expected depth of weathering coupled with relatively steep slope angles and significant groundwater. In response, geotechnical and operations teams overcame numerous monitoring challenges with prisms and radar to develop a simple and effective monitoring system coupled to a Trigger Action Response Plan (TARP) which enabled continued safe operations while reducing ore loss. Observations of previous slope performance of these two pits allowed for greater confidence in empirical failure runout calculations that was used to specify the standoff widths for the exclusion zones in the pit. Back analysis of the slope as-built performance after the first indications of slope distress was also conducted. The back analysis was used to confirm rock mass parameters for modelling while being utilised as a reality check for the stability analysis. The stability analysis indicated that leaving a large step-out or buttress would not prevent the displacement, resulting in some ore being sacrificed to ensure the safety of personnel. Key learnings from this experience highlight the importance of: • up-to-date geological interpretation of the depth of weathering • ensuring slope design guidance is reviewed and updated as latest information (ie geology and monitoring) is received • having multiple complementary slope monitoring methods to ensure redundancy • ensuring visual observations and as-built performance are utilised as a reality check to provide greater confidence in stability analysis and design guidance.

Jun 22, 2022

By P C. J Blackney, I M. Glacken

Spotted Quoll is a massive sulfide nickel deposit located in the Forrestania greenstone belt in the Archaean Yilgarn block in Western Australia. Discovered in October 2007, mining has progressed from open pit to underground and currently uses longhole open stoping with paste fill as the primary stoping method. Immediately prior to 2019, the Mineral Resource estimate (MRE) was defined by a single grade domain of nickel greater than or equal to 0.8 per cent, irrespective of the host lithology, a legacy of the original ore wireframe being built using explicit methods. While a number of obvious structural offsets were honoured in this nickel grade domain, only one modelled fault was used to undertake domaining of arsenic. From 2019 onwards, implicit modelling in Leapfrog Geo™ was used to construct a mine-scale geological model, which triggered the definition of a high-grade core of massive/matrix nickel sulfides surrounded by a low-grade halo of stringer/disseminated nickel sulfides in the surrounding rock. As part of the evolution of the geological model and with the aid of Seequent Central™ to allow collaboration between site-based mine geologists, Perth-based resource geologists and Melbourne-based consultants, a detailed review of the structural mapping was carried out as additional information from underground development became available. This allowed numerous faults and shears to be identified – particularly in the lower half of the mine. These were used to define further structural domains and to refine the understanding of the nickel and arsenic grade distributions in the mineralised envelope. The increased definition to the domains provided by the geological model resulted in a significant improvement in the accuracy of the Mineral Resource estimate, as measured by reconciliation using voids of the mined stopes determined from the cavity monitoring survey (CMS).

Mar 22, 2022

By G R. F Alvear Flores

Mineral resources are becoming more complex in composition and structure making it more difficult to produce clean concentrates for primary metal smelting. In parallel, providing technological solutions to the recycling and recovery of end-of-life materials is becoming more important in moving towards the goal of increasing circularity. The availability of fundamental thermodynamic data and advanced thermodynamic tools greatly assists in evaluating these complexities and their impact on existing and new processes. In addition, it is fundamental to support the economic performance of smelters. This paper describes several examples on how fundamental work can be applied to industrial processing..

Jun 17, 2024

By G J. Lyman

Sampling of grain for mycotoxins is challenging in that some mycotoxins, such as Ochratoxin A (OTA), have very low permitted levels and the kernels carrying the mycotoxin may be highly localised within the bulk of the grain as ‘hot spots’. Sampling for genetically modified organisms (GMOs) can be fraught with similar problems, especially if the contamination is adventitious and random. Incremental sampling under these circumstances can be shown to lead to a high variance in the sampling result.A new design of sampler for grain and other free-flowing particulates has been developed that is effective in practically eliminating the sampling variance due to distributional heterogeneity (DH).This paper introduces the design and argues that the sampler should be free of sampling variance due to DH.CITATION:Lyman, G J, 2017. A new sampler for grain and other free-flowing particulates, in Proceedings Eighth World Conference on Sampling and Blending , pp 277–280 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By J H. Heo, J H. Park, M J. Lee

In this paper, the challenging points regarding the high temperature physical chemistry of slags to achieve the improved and stable electric arc furnace (EAF) or electric smelting furnace (ESF) technology on the way to green steel will be reviewed, and the recent experimental and modelling research will be discussed. For example, the initial melting phenomena of hot briquetted iron (HBI) and the slag formation behaviour was observed using a high-frequency induction furnace. Main component of gangue oxides in HBI was SiO2, Al2O3, and CaO in conjunction with unreduced iron oxide. To increase the dephosphorisation efficiency, the distribution ratio of phosphorus between metal and slag was calculated using FactSage™ software, version 8.2 (CRCT ThermFact, Inc., Montreal, Canada) and was compared to the measured results. The optimisation of slag chemistry is required not only for maximum dephosphorisation efficiency with good slag foamability but also for minimum slag volume with less refractory corrosion in EAF process. The slag chemistry is also one of key parameters affecting the operation efficiency in ESF in view of FeO reduction behaviour, viscosity, sulfide capacity, etc.

Jun 19, 2024

By H A. Linn, K Winn, C W. Lee

The Q-slope method for rock slope engineering was developed to enable engineering geologists and rock engineers to rapidly assess the stability of excavated rock slopes in the field and make optimal adjustments to slope angles as rock mass conditions become apparent during construction of road cuts or benches. An empirical relationship between Q-slope and long-term stable slope angle is now supported through over 500 cases studies from Asia, Australia, the Americas and Europe. This paper presents about the stability analysis by first-ever applying Q-slope method on abandoned quarry wall in Singapore. The 30 m high rock slope which is composed of monzogranite rock was severely damaged by blasting operation. As the rock slope is intended for public view the objective was to retain the natural outlook and without any artificial support application thus manual scaling was carried out to clear the loosed rock blocks. In the end stable slope angle of clean rock face is determined once again by Q-slope method.

Nov 29, 2022

By J M. Galvin

The traditional engineering approach to assessing stability is based on comparing resisting force (capacity) to driving force (demand), or strength to working stress. In underground coal geomechanics, considerable effort has been expended on quantifying the strength of rock structures. However, this has not been matched by advances in determining the load acting on these structures, reflecting a reluctance by some to embrace numerical modelling to assess load magnitudes and distributions. Numerical modelling is a valuable aid as loading environments are a function of both the stiffness of the mine workings and the stiffness of the superincumbent strata and are statically indeterminate in most cases.This paper defines stiffness, which is often confused with elastic modulus. It shows that, effectively, stiffness encapsulates geology, depth of mining, panel width, pillar width and mining height. Therefore, these factors are variables that need to be taken into account when determining stress magnitudes and distributions about mine workings. A range of examples are presented that illustrate the significance of the stiffness of the superincumbent strata on surface subsidence; the magnitude and distribution of pillar and abutment load; and aspects of bord and pillar mining, pillar extraction and longwall mining. These examples provide bases for identifying the limitations of some empirical approaches to mine design, identifying how to compensate for some of these in design processes; and emphasising the need to make greater use of numerical modelling in understanding and quantifying loading environments in underground coal mining.CITATION:Galvin, J M, 2014. The significance of superincumbent strata stiffness and its impacts on coalmine design, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference , pp 3–16 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 5, 2014