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By J N. Farrell

Metallurgists frequently use a small number of large samples to characterise expected mill performance, with the a priori assumption that these few samples are representative of the entire deposit. Geometallurgical sampling is becoming more prevalent as a way to use many smaller samples to indicate the expected recovery as part of the Mineral Resource or Ore Reserve estimation.The evaluation of magnetite deposits involves specialised approaches to sample preparation, sample analysis and resource estimation. The sampling protocol for magnetite deposits will typically include the use of Davis Tube analysis. The Davis Tube is a mini-pilot plant that is used for determining the mass magnetic recovery from a small amount of sample ground to a specific size. The magnetic concentrate may then be analysed and together with the mass magnetic recovery, may be used to simulate the expected mill recovery. The magnetite sampling protocol is specific to each deposit, and is typically designed around a specific metallurgical flow sheet.During resource modelling, the mass magnetic recoveries and concentrate grades may be estimated directly or assigned to a block model using regressions with other chemical constituents. For estimation, the concentrate grades are weighted to account for the different mass magnetic recoveries of each sample and the impact of these differences on the concentrate estimates.

Sep 5, 2011

By P Kittler

In the spectrum of mining-related disciplines, geometallurgy sits between resource geology and metallurgical engineering. Unlike its neighbours, it is a relatively young discipline and its concepts, procedures and techniques are still evolving. Relevant geometallurgical issues differ from one deposit to the next so there is no single template that can be used in all situations, meaning that geometallurgy programs are nearly always customised and tailored to the deposit and the situation.Over time, a number of key mistakes are seen to emerge regularly. The eventual impact of these mistakes can vary from suboptimal performance of mine and plant to complete failure of the operation. For instance, poor characterisation of ore lithologies and their spatial distribution can have negative impacts on processing plant throughput. However, when combined with failure to identify critical blending constraints it can result in a totally inoperable plant.A number of common mistakes committed during geometallurgical programs are discussed and some preferred alternative approaches are suggested

Sep 5, 2011

By G D. Matthews, M E. Haylett, S Khosrowshahi, A Weeks

Effective domaining is fundamental to geostatistical modelling for grade control. Through analysis of lithological, structural and alteration logging data, effective groupings (domains) can be identified and employed for estimation or simulation purposes.The poor definition of domains can adversely affect the grade control model resulting in a misinterpretation of the optimal ore-waste boundary and ultimately reduces the quality of recovered ore. The implementation of an appropriate domaining strategy is therefore expected to improve recovery and reconciliation.A thorough understanding of the geology of the deposit and adequate sample data is required for selecting domains. For new deposits, a resource drill database and resource model may be the only information available. Where extension to a previous operation is taking place, historic grade control, mapping and exposed geology may be used to improve domain selection. Preconceptions about domains, should they exist, need to be re-evaluated and tested to ensure they are fit for the purposes of grade control.While mining progresses, the domain model is re-evaluated to ensure that the previous interpretation is still suitable for the present configuration and geology. The grade control process, being iterative, lends itself to regular review and continuous improvement as further data is collected during the grade control cycle. Regular updates to the geology model, mapping, geostatistical data analysis and review of variography will provide indications of a changing domaining environment.Narrow vein gold deposits, which may have several factors influencing mineralisation, present considerable domaining challenges. By scrutinising the data, sample populations can be grouped into domains, which not only improve ore recovery, but help assist in the development of a mine geology model.CITATION:Matthews, G D, Haylett, M E, Weeks, A and Khosrowshahi, S, 2014. Effective domain selection for grade control in narrow vein gold deposits, in Proceedings Ninth International Mining Geology Conference 2014 , pp 191–196 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 18, 2014

By P Holtham, W Valery, P Baguley, A Jankovic

There is a growing interest in magnetite ores because of the increasing demand for this commodity. With these ores, there is significant cost associated with milling the ore to fine sizes using ball mills in closed circuit with hydrocyclones. Cyclone classification efficiency tends to be poor due to the large difference in density between magnetite and gangue. This decreases the grinding circuit efficiency and results in over-grinding of magnetite. The objective of the work described in this paper was to modify the Bond locked cycle milling test procedure to quantify the loss of grinding circuit efficiency due to the mineral density effect. The locked cycle test procedure described here includes a stage of magnetic separation treating the closing screen undersize, which allows simulation of magnetite classification. The effect of classifier efficiency on low-density particles (non-magnetics) was simulated by altering the proportion of closing screen undersize bypass returning to the mill. Using a magnetic separator and a screen in the magnetics stream, different proportions of the magnetic fraction can be bypassed, thus allowing simulation of the effect of particle density on classification efficiency. This laboratory test work has confirmed that the impact of mineral density on cyclone efficiency subsequently has a crucial negative effect on ball mill circuit capacity. The results are in good agreement with reductions in capacity observed in practice. Multicomponent grinding and classification models were also developed in the LIMN software environment and were able to successfully simulate both the industrial and the laboratory ball mill circuit. The test and modelling procedures established in this project could be used for improved design of new magnetite ball mill grinding circuits as well as the optimisation of existing circuits.CITATION:Jankovic, A, Baguley, P, Valery, W and Holtham, P, 2015. Effect of mineral density for milling magnetite ores, in Proceedings Iron Ore 2015, pp 159–164 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By J Player, G Sweby

The material properties and hence performance of saturated alluvial sediments slope can be incorrectly forecast if the water content is not preserved, and materials properties not correctly determined. The occurrence of saturated sediments in the Western Australia (WA) Goldfields, while not common, should be a significant investigation focus. Geotechnical engineers new to the area may be unaware of this and hence the importance of correct testing and determination of the material strength. Application of appropriate analysis to determine stable pit slopes to an acceptable level of risk, is not possible unless the appropriate strength and hydrogeological parameters have been established at the outset. A back analysis is presented of a pit that had extensive slope failures in alluvial clay-rich sediments with discussion on the approach adopted by the original design engineers to assess pit wall stability and consequent poor slope performance. Learnings from a full pit 3D back analysis are presented, with an approach to geotechnical and hydrogeological investigations and analysis for slopes in similar materials.

Jun 22, 2022

By C K. Suzuki, J A. Yanaguizawa, D M. F de Santana, L R. P Leite, A H. Shinohara

In the present work, the microstructure and mechanical properties of structural mortar from glass insulators were studied by X-ray fluorescence, X-ray diffraction, infrared spectroscopy, microhardness and compression testings. The investigated glass insulators were manufactured between the 1960 and 1990 years and had been used in 230 kV transmission lines. The results evidenced that the structural mortar of glass insulator was replaced from Portland to aluminous cement along the years. The crystalline phases of the mortar were identified and mechanical properties were correlated.

Jan 1, 2008

By P Radulovic, V Lawson, M Muller, J Wallace

The Mount Isa Copper Concentrator was commissioned in 1973. Since commissioning some significant upgrades have been undertaken such as: • the replacement of the rod mill/ball mill circuit with AG mills and the subsequent conversion of the AG mills to SAG Mills. • the introduction of columns as retreat cleaners in 1987, then reallocated as prefloat cleaners in 1994 and rougher cleaners in 1996.• the repurposing of some rougher capacity to preflotation roughing to remove carbonaceous pyrite and talc in 1994.• the introduction of a Jameson Cell for preflotation cleaning in 2000. • the expansion of the rougher and cleaner circuits in 2002 with the inclusion of 6 x 100 m3 Wemco cells to replace the capacity lost to preflotation and to increase residence time and improve recovery. In 2013 work commenced to replace the cleaner circuit after 40 years of operation. The new cleaner circuit, consisting of 3 x B5400/18 Jameson Cells, replaced the rougher cleaner columns, cleaners, recleaners and retreat Agitair banks and was commissioned in Sep 2015. The new cleaner circuit was configured as two cells in series producing the final concentrate and a cleaner scavenger cell to supplement the existing Wemco cleaner scavenger cells. The performance of the new circuit is discussed.CITATION:Lawson, V, Muller, M, Radulovic, P and Wallace, J, 2017. Mt Isa copper concentrator cleaner circuit redesign, in Proceedings MetPlant 2017, pp 279–287 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By Y D. Jeon, K S. Kim, C-H Eom, C M. Yoon

The carbon neutrality continues to require reduction of carbon usage in ironmaking and steelmaking processes. Specially, it is expected that the hot metal ratio (HMR) in the steelmaking process should be reduced essentially. Unfortunately, the reduction of the HMR in converter can bring about poor environment for nitrogen removal from molten Fe. From this situation, nitrogen prediction model has been developed to understand the fundamental of behaviour of nitrogen and quantitatively interpret its content changes in the converter process. Thermodynamic and kinetic approaches were improved based on existing mathematical model and attempted to predict nitrogen content in realtime by combining process data. In present study, heat supply from the oxidation (mainly carbon and silicon) and CO evolution in the converter are considered, and scrap melting due to the heat transfer from the molten Fe to the solid scrap charged in the converter also be considered.

Aug 21, 2024

By S Dykes, R J. McCarthy, B Klein

There is growing interest in the mining industry on the application of ore sorting. While many are familiar with particle sorting, including the limitations that technology presents (e.g. throughput), bulk sorting, with its higher throughput potential, is less understood. Despite the potential to sort at higher throughputs, few operations have adopted bulk sorting processes, certainly not at large scale. It is suggested that the inability to reliably predict outcomes from bulk sorting may be limiting its adoption in mining projects. Consequently, an evaluation approach for bulk ore sorting has been developed such that mass pulls and grade upgrades can be predicted in the context of a mining study. The approach allows for evaluation of drill core assays and application of the consequently derived heterogeneity relationships to the block model for estimation of sorting outcomes. These processes were applied to conveyor-based bulk sorting for the CuMo project in Idaho, USA and are described in this paper.

Nov 10, 2020

By J Lyons, S Baker, D MacHunter, D Pepper

Mineral processing plants require a storage buffer to bridge differences in production rates between mining and processing. Where coarse ores are processed, such as coal or hard rock, this buffer may be an ore stockpile or silo. For wet-mining processes, eg dredging or hydraulic mining, or where fine ores are slurried close to the mining face, a surge-bin is used to contain the plant feed and smooth out the variations in mining rates. These bins have gradually evolved from simple storage vessels to units that are now frequently part of the mineral separation process itself, such as providing a desliming function to remove deleterious ultrafine gangue. This feed conditioning is often essential to achieve the levels of plant performance required in times of declining ore grades and or where inherent ore characteristics make separations harder to achieve. To achieve these dual roles requires careful consideration of bin design factors such as geometry and lining selection and increased use of instrumentation and advanced, or remotely supervised, control systems. All this ensures they provide capacity to smooth out variations in mining rates and guarantees that when conditioning ores or adjusting slurry densities ahead of the plant it is achieved without loss of valuable minerals. This paper examines the evolution of the modern surge-bin from a simple, so called, constant density tank with its inherent mass-flow compromises, limited feed preparation and beneficiation abilities, and footprint penalty, to a current state-of-the-art surge-bin, the LFCU, with a control system which provides demonstrable steady outputs, while conditioning and in some cases beneficiating the ROM material and all from a highly compact unit. It further discusses their use in other applications around the world, for example providing the necessary security for long distant high-density pumping systems; constant high density, low water usage, tailings disposal pipelines and high capacity ultrafine iron ore beneficiation.

Aug 24, 2022

By M Chen, Q D. Gao, Y G. Hu, P Yan, W B. Lu

The safety and stability of construction structures are often affected by blast-induced waves. Investigating the generation mechanism of shear wave (S-wave) during blasting is important, because it has a strong effect in blasting damage. In this paper the generation mechanism and verification of S-wave was studied analytically and numerically. Under the finite velocity of detonation (VOD) of cylindrical charge or the compression wave (P-wave) communicating with the interface of different media during the propagation, the generation mechanism of S-wave was analysed. Propagation of blasting wave in cylindrical charge was simulated with the elastic model, and the generation of S-wave induced by finite VOD was proved. To compare with different numerical methods in simulating the generation of S-wave, the blasting process of instantaneous detonation was simulated by using the elastic model, elastic-plastic model and smoothed particle hydrodynamics and finite element method (SPH-FEM) coupled model. Results demonstrate that the S-wave could not be found in middle section of the charge if the elastic model is employed. But when using elastic-plastic model and SPH-FEM coupled model, the generation of S-wave could be verified. Under the SPH-FEM condition, the amplitude of S-wave is larger and the arrival time difference between P-wave and S-wave is closer to theoretical results.CITATION:Gao, Q D, Lu, W B, Hu, Y G, Chen, M and Yan, P, 2015. Comparison of the generation of shear wave with different simulation approaches, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 79–88 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

By M Hawkes, Z Ji Gang, Z Ming, R Hassell

As underground mines become more geotechnically challenging with increasing depth and excavation size, the requirement for ground support to be installed as per design becomes more critical. The verification of installation quality for cable bolts and grouted rock bolts is difficult to assess. Current methods to control quality have limitations; pull testing is largely inconclusive with only extremely poor installation being identifiable. Audits during installation can only capture a small percentage of installed bolts. Following large rock mass displacement from either squeezing ground or seismic events, even previously well installed bolts may have yielded and require replacement. A method to provide an improved understanding of the reinforcement installation quality is Non- Destructive Testing (NDT) using acoustic reflection. To validate the accuracy of an NDT system, both plain and bulbed strand cable bolts were grouted in clear plastic tubes. The encapsulation grout quality was deliberately varied from full encapsulation through to partial encapsulation and a range of different size voids. The clear tubes allowed the ground encapsulation to be observed. Cable bolts strands were cut at varying lengths and different water cement grout ratios were used. Acoustic testing of the cable bolt specimens was completed blind; the technicians were not aware of what was being tested. The NDT results correlated well with the grout encapsulation, with differences between full encapsulation, minor voids and major voids being determined. The different water cement ratio and bolt lengths (including when partially cut) were also identifiable but with some discrepancies. Trials of the technology underground have also shown the data collection process to be relatively quick with each bolt taking 1-2 minutes to test, with interpretation of the results able to be completed soon after. The NDT results collected from the underground trial showed a wide variance in cable bolt grout encapsulation quality indicating that there were installation issues.

Mar 15, 2021

By F Flitti, M Haest, O Dominguez, D Mittrup, G Hird

The automated geology interpretation (AGI) tool has been developed in BHP Billiton to automate stratigraphy logging of drill holes, using any available quantitative data sets. At present, AGI is set-up to utilise geochemistry and mineralogy from infrared spectroscopic data to predict stratigraphy. Once the AGI tool is calibrated, results show that the tool is capable of automatically defining stratigraphy across all of the deposit types, encountered by BHP Billiton Iron Ore in the north-west of Western Australia. Accuracy of AGI at predicting stratigraphy is on average better than 75 per cent, with average accuracies exceeding 85 per cent for some deposit types. The AGI tool can deliver fast, accurate, consistent and objective geological interpretations.AGI is currently being implemented in BHP Billiton Iron Ore Exploration to streamline the drill hole logging process and allow geologists to spend less time defining stratigraphy at the drill hole level and more time investigating stratigraphy in 3D. This will deliver improved geology models, with significant downstream benefits in terms of better resource models, more accurate mine plans, higher plant efficiencies and more consistent ore products, driving productivity in BHP Billiton Iron Ore over the next decade.CITATION:Mittrup, D, Flitti, F, Hird, G, Haest, M and Dominguez, O, 2015. Semi-automated geological interpretation using assay and infrared spectroscopic sensing parameters towards improvements in geological modelling, in Proceedings Iron Ore 2015, pp 313–318 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015

By D Corley, J Moore, M Grant, A, W R

Resource estimates are the corner stone of technical and investment decision-making. Prior to mining, resource estimation uncertainty has the greatest potential to lead to poor investment decisions, despite a significant component of resource estimation uncertainty being unknowable at this critical stage in the mining cycle. This presents a conundrum to the resource geologist in terms of risk evaluation and resource classification. Ahead of mining, there is normally considerable focus on drill hole spacing analysis to determine the ‘optimal’ drill hole spacing, taking grade and geological continuity into account; cost-benefit analyses balance improved resource definition against cost; the law of diminishing returns and the exponential cost increases acting together as spacing is reduced. Typically, a lower limit to the drill hole spacing is identified. After completing the resource drilling to an agreed spacing, resource estimation is then undertaken. At this point it is common to attempt to bracket the resource estimation uncertainty. In many cases conditional simulation is used, based on a modelled, but largely assumed, variogram model. It is also assumed that the histogram of the available drill hole sample data is representative of the in-ground mineralisation. The purpose of this paper is not to diminish the importance of drill hole spacing and simulation studies, but rather to illuminate an important aspect of estimation uncertainty that, although previously recognised, is typically overlooked – the question of how representative the available data set is in characterising the true (but unknown) distribution of mineralisation. To do this, we lift the lid on one of OceanaGold’s former operations, the mined-out Globe Progress Mine, by resurrecting a high quality, close-spaced, reverse circulation (RC) grade control data set. The Globe Progress Mine is within the West Coast Region of New Zealand, it was closed and transitioned to rehabilitation in 2016 and is now known as the Reefton Restoration Project. The exhaustive Globe Progress grade control data was used to repeatedly ‘redrill’ the deposit by extracting 35 m × 35 m spaced subsets from the original 5 m × 5 m spaced grade control data. Utilising closely spaced grade control data removed the need for assumptions regarding short range continuity, which are necessary with forward-looking analyses that are based upon broader spaced resource drilling. The extraction process used a nearest neighbourhood algorithm, repeatedly moving the origin in 5 mE, or 5 mN increments. Individual resource estimates were then completed for each of the extracted drill hole data sets (49 in total) as well as a grade control estimate based upon the exhaustive data set. Whilst the data unpinning each of the 49 estimates changed, the geological assumptions, variography, and modelling parameters remained constant. This approach was taken to isolate the impact of changing the input data. The 49 estimates were then compared against each other and the grade control estimate. The mean of all 49 sensitivity estimates was close to that of the grade control estimate in terms of contained gold, tonnes and grade. Whilst it is acknowledged that the grade control estimate itself is subject to some degree of estimation uncertainty, the close match between the average of the 49 estimates and the grade control estimate suggests that the resource estimation methodology is reasonable and appropriate. Whilst this comparison is important, the focus of this study is on the component of estimation uncertainty related to the underlying data, and this is reflected in the spread across the estimates. The spread across the 49 global estimates (highest to lowest) for this particular Mineral Resource Estimation Conference 2023 | Perth, Australia | 24–25 May 2023 142 case study was found to be significant (approximately 20 per cent in grade and metal) and that is attributable solely to the underlying data. This exercise quantifies a component of the estimation uncertainty that is inherent to all drill hole data and is distinct from the uncertainties associated with modelling methodology choices, sample and subsample quality and drill hole spacing-related interpolation uncertainty. Importantly, this uncertainty is unknowable prior to mining; we can only directly compare the resource drill hole data against grade control data after mining has taken place. For the case study, approximately 65 per cent of the estimates fell within 5 per cent of the grade control estimate for contained-gold, suggesting that for many projects the histogram of drill hole data is unlikely to differ noticeably from that of the in-ground resource. However, about 15 per cent of the estimates in this study differed by more than 7.5 per cent, suggesting that a not-insignificant proportion of estimates will be materially compromised. Whether or not the available drill hole data is representative comes down to the ‘luck of the draw’ and cannot be known at the time of resource estimation. Given the challenge of attempting to evaluate forward-looking estimation uncertainty, a component of which that can only be quantified retrospectively, what should we do as resource geologists? What are the implications for risk evaluation, resource classification and reconciliation? Furthermore, without rigorous post-mining data checks, resource geologists may conflate suboptimal modelling with the shortcomings of the underlying data. An example of this problem is discussed in the following section.

May 24, 2023

By J Seery, N Savage, A Wilson, L Nicholas

Geological modelling provides a means of spatially representing the three dimensional distribution of geological information to downstream stakeholders. The geologist completing the modelling work intimately understands the varying degrees of confidence, assumptions and extrapolation required to honour the data. Geological models are often taken and used by stakeholders without fully understanding this modelling process. This can lead to confusion amongst stakeholders when the geological model shows variable reconciliation. A method for visually communicating the confidence of the spatial distribution of geological models has been created by the Rio Tinto Iron Ore structural geology group for use primarily in geotechnical engineering investigations. A numeric confidence rating is assigned to each geological data point used in the creation of a geological surface. This is based on data type, collection method and reliability to indicate potential error in distance from its modelled location. In regions of sparse data, confidence ratings are inserted based upon the geologistÆs experience and knowledge of the geology, whereas mapped geological contacts or drill hole intersections are assigned a higher confidence rating. A regular grid of points is registered to the geological surface and each of these grid points is assigned a confidence rating using an inverse distance weighting using a nearest neighbour approach. The resulting grid is colour coded according to the confidence rating to provide a visual representation of the variable confidence of the geological surface in three dimensions. Subjectivity and bias from the geologist is minimised by critically analysing the input geological data and then applying this methodology to represent the confidence in the spatial characteristics of geological models. Understanding of this confidence enables mining professionals to make informed decisions and identify areas that require further geological investigative work. CITATION:Savage, N, Nicholas, L, Wilson, A and Seery, J, 2013. Visual communication of geological confidence - a move toward a less subjective approach, in Proceedings Iron Ore 2013 , pp 169-174 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By Y H. Zhu, X X. Tang, Y C. Yin, M L. Xing

Based on the stiffness theory, the stiffness difference and energy supply of surrounding rocks are important inducing factors for strain burst. However, due to the lack of multi-level low stiffness testing machine, there are few experimental studies on rock failure mechanisms under the influence of loading stiffness. This paper introduced a self-developed rock testing system with changeable stiffness. The main testing machine of this system is a combined structure of inner and outer frame. The change in the loading stiffness is achieved by using a stiffness servo control system to control the energy accumulation in the inner frame. The tests of the sandstone specimens under three different loading stiffnesses in the testing system showed that the loading stiffness did not significantly affect either the uniaxial compressive strength or the Young’s modulus of the rock. However, the post-peak stress-strain curve of the rock became smoother and steeper when the loading stiffness was decreased, and the stress drop rate increased. It is shown that the stress drop rate had a power function correlation with the loading stiffness. After the peak load, the inner frame of the testing system rebounded several times at high speeds. The magnitude of the instantaneous rebound speed and the rebound duration increased with the decrease of loading stiffness. Both the mean rebound velocity and the total rebound deformation had power function correlations with the loading stiffness. The loading stiffness has limited effect on the energy storage and energy dissipation characteristics of the specimen, while the released energy of the testing machine increases as the loading stiffness decreases, which is the key factor affecting the failure mode of the specimen. According to the test results, a rock burst mechanical model considering the stiffness is established, and the energy supply mechanism of rock burst is quantitatively explained.

Nov 29, 2022

By Tozawa K, Nishimura T, Sasaki K

Liquidus surfaces in a part of the systems ZnO-PbO-Si02 and ZnO-"FeO"-SiO 2 were constructed by the quenching method. The ex- periments were carried out in air in the system ZnO-PbO-Si02. In the part investigated the primary phases were three ternary compounds (PbO.ZnOòSiO2, 2PbOòZnO.2SiO2 and barysilite), three lead silicates, Zn2SiO4 and SiO2. Iso- therms on the liquidus surface of each primary phase field were determined from 750 to 1300¦C. In the system ZnO-"FeO"-SiO 2 the experiments were carried out in an atmosphere of purified nitrogen. In the part investigated the primary phases were Fe2SiO4, Zn2SiO4 and Si02. Iso- therms on the liquidus surface of each primary phase field from 1150 to 1300¦C and the ternary eutectic (1130¦C, 15.9% ZnO, 48.2% "FeO" and 35.9% Si02) were determined.

Jan 1, 1980

By X Z. Sun, N Jiang, J H. Zhao, C X. Wang, L Y. Bai

In backfill grouting for underground coalmines, the filling materials strengthen the caving rock and support the overlying strata to reduce surface subsidence. The broken roof strata fail and collapse during mining operations without appropriate supporting measures being taken. It is difficult to perform continuous backfill mining on the working face of such roofs using the existing mining technology. Therefore, in order to solve the above problems, fly ash and mine water are considered as filling materials, and flow characteristics of fly-ash slurry are investigated through laboratory experiments and theoretical analyses. Laws governing the diffusion of fly-ash slurry in the void of caving rock masses and in the void between a caving rock mass and a basic roof are obtained and verified. Based on the results obtained from the above analyses and field conditions at the Zhaoguan coalmine, Shandong Province, China, a cave backfill grouting system of the hauling pipeline is developed and successfully tested at the 1703 working face. The results demonstrate that a filling rate of 43.46 per cent is achieved, and the surface subsidence coefficient of the grouting process is found to be 0.475. Compared to the total caving method, the proposed system is found to achieve a reduction rate of 40.63 per cent. This effectively helps in lowering the value of the surface subsidence coefficient. Fly ash and mine water, considered as primary materials in this study, also play a significant role in improving the air quality and water environment.

Nov 29, 2022

By B King

A large number of mineral deposits contain regions in which it is economically beneficial to extract ore both via open pit and underground mining techniques. Current industry practice lacks an effective means to establish the extent of the open pit and underground mining areas for an individual deposit. We present a mixed integer programming model for scheduling both the open pit and underground mine that can be used to create a holistic extraction sequence for a specific deposit. The model considers both spatial and temporal elements of the open pit and underground mines in order to maximise the net present value of the entire deposit, while adhering to its production, processing and block sequencing constraints. By doing so, we can schedule the open pit and underground in concert.CITATION:King, B, 2014. Modelling open pit and underground production scheduling in concert, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 369–374 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By J Foo, T Kleinschmidt, B Reynolds, K Kennewell

The consideration of complex supply chains often highlights multiple system bottlenecks that are localised and dynamic – they shift depending on what variability last influenced the system. Using the understanding of a dynamic system model, synergies between items that tackle localised bottlenecks can be understood to generate a suite of solutions. These can be simple solutions, such as a couple of new conveyors placed in series, or more complex ones, including buffer dynamics (capacity, location, behaviour, etc).Each solution in the suite will have an associated uplift in system performance and an associated cost of implementation. Dynamic simulations can address each situation in turn and estimate the projected improvement it would offer. However, these solutions will have different benefits when implemented together, and each solution will give different uplift depending on what other solutions have already been assumed. If the number of solutions is numerous, traditional dynamic simulation analysis becomes the bottleneck, limiting options analysis to the processing power available.This paper will illustrate the use of a new technique applied as part of a capital growth optimisation project with a major iron ore producer. Metamodelling is the creation of a model of a model; in this case study, the focus is on developing a response surface representing the suite of solutions. This can be achieved through a combination of dynamic modelling and an appropriate mathematical process called design of experiments. The result is an approximation surface of the outcomes of the dynamic model, encapsulating interactions between key elements of the value chain.This modelling approach provides a number of advantages compared to traditional dynamic modelling approaches, including but not limited to:early and rapid evaluation of a large range of potential solutionsaccommodation of multiple initial states of the value chainoptimisation of the overall suite of upgrades (down to route-level upgrades) based on business objectiveseasy re-evaluation of outcomes when key inputs such as costs change.CITATION:Kleinschmidt, T, Foo, J, Reynolds, B and Kennewell, K, 2015. Case study of iron ore value chain optimisation, in Proceedings Iron Ore 2015, pp 605–612 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 13, 2015