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Red sand is the by-product of aluminum refinery processing. It is susceptible to wind erosion and the emitted particles may cause serious environmental and safety issues. Lignosulfonate stabilizers are one of the promising non-traditional stabilizers to mitigate such issues. However, the contribution of the improvement on each mechanical property to the modification of the final erosion resistance was rarely analyzed, especially for coarse sandy bauxite residue. Thus, this study was conducted to analyze the relationship between improved mechanical properties and corresponding dust control performance of bauxite residue by applying two lignosulfonate stabilizers LS-S and LS-C. Results show that both of them provide improved water retention with higher concentration. However, the improvement is not substantial when the concentration is more than 4%. Two stabilizers generate nearly the same results in the optimum moisture content (OMC) and maximum dry density (MDD) tests, in which both of them reduce the OMC by about 10% and slightly increase the MDD. The addition of LS has virtually no influence on the density of the formed crust, but the crust thickness reduces with the increase of LS concentration. Furthermore, both penetration resistance and unconfined compressive strength (UCS) evidently increase with LS concentration, and LS-S apparently outperforms LS-C. Wind erosion tests have demonstrated that both LS-S and LS-C improve wind erosion resistance, and LS-S-treated sample can withstand longer period of wind attack, which is consistent with the penetration and UCS results that LS-S outperforms LS-C. Importantly, evidences presented in this paper illustrate that the improved mechanical properties appear to increase dust control performance.

© 2018 Elsevier B.V. As hydraulic fracturing as a means to enhance coal bed methane was banned in some countries due to possible negative environmental impacts, the microwave heating was proposed as an alternative approach to enhance coal permeability and thus gas productivity. One of the mechanisms on improving coal permeability using microwave irradiation is that thermal stress caused by microwave heating generates fractures. To study the influence of microwave settings to the heating effect of coal samples, a coupled mathematical model for electromagnetic, heat and mass transfer in the process of microwave heating is proposed and is numerically implemented using a finite element method. This coupled model for microwave heating have considered heat and mass transfer, and is validated by comparison with experimental results. Then it is used to simulate the influence of frequency, power and moisture capacity on microwave heating. The simulation results show that microwave heating of coal is highly sensitive to excitation frequency. Frequencies around 3.45 GHz contribute to significant thermal heterogeneity. With the same energy input, different powers do not influence the overall heating effect, but higher powers cause greater thermal heterogeneity. Moisture capacity also has great effect on microwave heating and thermal distribution pattern. Under 2.45 GHz and 1.0 kW, the coal sample with moisture capacity of 5% has the best microwave heating effect.

This paper presents the results of research to develop a simple method of determining deformation at the crest of a soil nailed wall. At the present time there is no established simplified method for accurately predicting soil nail walls deformation, with the current predictive methods being either an empirical approach or based on the use of numerical analysis. By carrying out a parametric study through the use of the finite element program PLAXIS, the effects of soil nail inclination, spacing and length, as well as the soil properties of stiffness and strength on soil nail wall deformation were assessed. The results indicated that although all of these elements had some ef-fect on deformation, soil effective cohesion had the greatest effect. The results were used to create two empirical prediction formulae and a series of design charts to determine wall crest deformation and these formulae were tested against case history data. This led to a minor modification to the formulae. The final calibrated empirical prediction formulae provide an estimation of wall movement to ±5mm with 80% accuracy, when compared to the case history data, and >95% accuracy when considering ±10mm, which is considered acceptable for most preliminary engineering designs. The introduction of these formulae will enable engineers to obtain an estimation of wall movement at an early stage without the necessity of carrying out relatively expensive and time consuming numerical analysis.

This is the second paper of a series authored by a collaboration of international researchers. It develops taxonomy for computer-based virtual reality simulators of relevance to the mining industry. A summary is presented of simulator types implemented in the industry, and continuums are used to explain concepts and issues that affect simulator development and integration. The paper classifies simulators and demonstrates that there are potentially many simulator formats still to be realised and implemented by the mining industry. Simulator issues that are often overlooked such as human factors, cognitive load and development costs and their impact on the development of sustainable simulator technologies are considered in some detail. Barriers to development and integration are mentioned, and the need for industry to engage with university-level research and develop a uniform and integrated approach are discussed. Finally, a brief case study is presented and conclusions are drawn about the current status and sustainability of simulator development in the mining industry.

Ground-penetrating radar (GPR) offers an inexpensive and rapid method for delineating the laterite profiles by acquiring fine-scale data from the ground. In a case study, a GPR survey was conducted at the Weipa bauxite mine in Australia, in which numerous pick points corresponding to the depth to the bauxite/ironstone boundary were acquired from the ground. These pick points were subsequently merged with the available exploration borehole data using four prediction algorithms, including standard linear regression (SLR), simple kriging with varying local means (SKLM), Bayesian integration (BAY), and ordinary co-located cokriging (OCCK). The required structural inputs for the aforementioned algorithms were derived from the modelled auto and cross-semi-variograms. The cross-validation results suggest that the SKLM approach yielded the most robust estimates. The comparison of these estimates with the actual mine floor also indicates that the inclusion of ancillary GPR data substantially improved the estimation quality.

Assessing uncertainty in grade-tonnage curves is rather crucial in resource estimation, as these curves provide information on how much ore within the deposit is above/below a given cut-off grade value. Conditional simulation algorithms can provide robust quantification of the ore production by generating multiple realisations of the ore deposits. However, when the ore deposit is characterised by multiple variables that are spatially correlated, these attributes need to be jointly simulated in order to preserve the spatial correlation. The application of co-simulation algorithms to the grade attributes requires large co-kriging matrices to be solved, making the whole process computationally inefficient and impractical. The minimum/maximum autocorrelation factor (MAF) transformation, however, offers a solution to the simulation of the multivariate deposits by transforming the original attributes into non-correlated orthogonal factors which can then be simulated independently, while preserving the spatial correlation among the attributes. This paper discusses the joint simulation of Al2O3, SiO2, Fe2O3, and TiO2 variables of a lateritic bauxite deposit through the MAF transformation and the results of the grade-tonnage curves for each realisation to express the uncertainty.

Generating short- and long-term mine production schedules in isolation and independently from each other means that only a local optimum can be achieved when each scheduling phase is carried out. The globally optimal solution however, can be achieved when integrating scheduling phases and accounting for the interaction between short-term and long-term activities simultaneously. This paper addresses the task of integrating short- and long-term production plans by combining the short-term objective of minimising deviation to targeted mill feed grade with the long-term objective of maximising net present value (NPV) into a single mathematical model. A case study is presented which compares the present values of the same stope data set scheduled via separate long and short-term models and than by the proposed integrated model which applies a predetermined penalty for each tonne of metal deviation to target for the respective ore tonnage being processed. This allows an operation to obtain a globally optimal scheduling regime when taking into consideration the cost and loss of value resulting from fluctuations in grade to the mill over the short-term.

The requirement for continuous improvement in the coal industry to achieve the combination of lower costs, greater capital efficiency and higher production. Longwall panels are now being mined at a faster rate requiring a commensurate increase in development rates. Development operations that cannot deliver continuity of longwall mining result in substantial flow on costs for the entire mine – from higher unit costs, lower production and loss of reliable supplier status in the coal market. A development unit which can remain well ahead of the longwall as a result of an efficient system – machines; human resources; supply logistics and efficient planning and scheduling is a vital factor in delivering a productive longwall mine. While capital solutions are often used to increase production, they may not lead to improved profitability. Often, a more efficient approach is to generate improvements through better management of existing equipment. Through an analysis of the development delays at an Australian longwall mine, a number of potential areas for improvement have been identified. Increasing operating time is one aspect of increasing roadway development rates and the second is increasing the cutting rate. The time and motion study which was carried out at the same mine identified the bolting and “shuttle car away” components of the cycle as holding the most potential for improvement.

A combination of self and peer assessment is a powerful and rich teaching and learning management tool that can be used to monitor and evaluate group performance in project work. An on-line system (SPARKPLUS â Self and Peer Assessment Resource Kit) has been developed to simplify this process for the academic. This system generates factors for both the peer assessment weighting to be applied for individual contribution and the studentâs perception of their contribution compared to their peers by using key assessment criteria and a rigorous algorithm that is applied to the student evaluations of themselves and their peers. This paper describes and evaluates the introduction of SPARKPLUS to assess the performance of Mining Engineering Undergraduates in Year 3 at The University of Queensland in the first semester of 2008 in two of their core undergraduate courses that required group project work to be completed for assessment. The results obtained from this initial trial show the potential for improving student behaviour in group work through a structured approach to monitoring and feedback of their performance. It was found that male students with GPAs ⤠5 tend to overestimate their contribution to group work more frequently than their peers whereas the opposite applies for male students with GPAs > 5.

The processes that take place during the development of a heating are difficult to visualise. Bulk coal self-heating tests at The University of Queensland (UQ) using a two-metre column are providing graphic evidence of the stages that occur during a heating. Data obtained from these tests, both temperature and corresponding off-gas evolution can be transformed into what is effectively a video-replay of the heating event. This is achieved by loading both sets of data into a newly developed animation package called Hotspot. The resulting animation is ideal for spontaneous combustion training purposes as the viewer can readily identify the different hot spot stages and corresponding off-gas signatures. Colour coding of the coal temperature, as the hot spot forms, highlights its location in the coal pile and shows its ability to migrate upwind. An added benefit of the package is that once a mine has been tested in the UQ two-metre column, there is a permanent record of that particular coals performance for mine personnel to view.

Virtual reality simulations are excellent tools for training, education, simulation of abnormal and dangerous conditions in mines and solving complex problems. The concept has been around for many decades but recent advances in hardware and software have brought the technology within the budgetary reach of ordinary users and researchers. Visual reality is now being used successfully within the minerals industry for data visualisation, accident reconstruction, simulation, risk analysis, hazard awareness and training. A research group on advanced computer graphics and virtual reality at the Institute of Sustainable Minerals Industry, University of Queensland, has been developing applications in conjunction with various research centres. They include drill rig training simulation, open pit simulation, training in identifying and barring down underground hazards, simulation of Instron rock testing, accident reconstruction, ventilation surveying and monitoring, and virtual mining education., Virtual reality simulations are excellent tools for training, education, simulation of abnormal and dangerous conditions in mines and solving complex problems. The concept has been around for many decades but recent advances in hardware and software have brought the technology within the budgetary reach of ordinary users and researchers. Visual reality is now being used successfully within the minerals industry for data visualisation, accident reconstruction, simulation, risk analysis, hazard awareness and training. A research group on advanced computer graphics and virtual reality at the Institute of Sustainable Minerals Industry, University of Queensland, has been developing applications in conjunction with various research centres. They include drill rig training simulation, open pit simulation, training in identifying and barring down underground hazards, simulation of Instron rock testing, accident reconstruction, ventilation surveying and monitoring, and virtual mining education.

Mining engineering degree programmes have traditionally had a practical emphasis and have been highly vocational in nature. However, there has been an increasing attention to the more scientific aspects of the discipline. More recently, the professional institutions, the industry and the community at large have placed increasing emphasis on broader aspects, including management, finance, humanity, environment and social issues. Employers of new graduates complain about their lack of practicality and readiness for employment at the sharp end on the mine site. Recent developments in the degree programme at the University of Queensland, Australia, are reviewed which attempt to address the problem. Particular attention is given to alternative learning programmes, including applications of virtual reality, practical experience at the university experimental mine and the undergraduate site learning programme. The experimental mine has three shafts giving access to the underground workings, the main shaft sunk to a depth of 88 m, a ventilation shaft, sunk to 46 m and an inclined shaft at 65 degrees from the horizontal which accesses the 43 m level. In 1999 Thiess Contractors and the university formed a strategic learning partnership involving a range of initiatives covering undergraduate education, company staff training, continuing professional education and research support, and in the following yea, the undergraduate site learning program was developed to provide a structured learning environment for senior undergraduate students within the minerals industry. Other initiatives currently incorporated or under development in the university programme include practically based theses and mine design projects, problem-based learning projects and the development of flexible learning aids, including field trips. International trips are also organised periodically and have included North America, South Africa, Europe and Russia. Undergraduates have opportunities for exchanges w, Mining engineering degree programmes have traditionally had a practical emphasis and have been highly vocational in nature. However, there has been an increasing attention to the more scientific aspects of the discipline. More recently, the professional institutions, the industry and the community at large have placed increasing emphasis on broader aspects, including management, finance, humanity, environment and social issues. Employers of new graduates complain about their lack of practicality and readiness for employment at the sharp end on the mine site. Recent developments in the degree programme at the University of Queensland, Australia, are reviewed which attempt to address the problem. Particular attention is given to alternative learning programmes, including applications of virtual reality, practical experience at the university experimental mine and the undergraduate site learning programme. The experimental mine has three shafts giving access to the underground workings, the main shaft sunk to a depth of 88 m, a ventilation shaft, sunk to 46 m and an inclined shaft at 65 degrees from the horizontal which accesses the 43 m level. In 1999 Thiess Contractors and the university formed a strategic learning partnership involving a range of initiatives covering undergraduate education, company staff training, continuing professional education and research support, and in the following yea, the undergraduate site learning program was developed to provide a structured learning environment for senior undergraduate students within the minerals industry. Other initiatives currently incorporated or under development in the university programme include practically based theses and mine design projects, problem-based learning projects and the development of flexible learning aids, including field trips. International trips are also organised periodically and have included North America, South Africa, Europe and Russia. Undergraduates have opportunities for exchanges w

Hydrogen sulphide (~S) as a seam gas has occurred in several locations in the Gennan Creek seam at Southern Colliery . This paper overviews the techniques developed to quantify the ~S content of the seam, overviews research into controlling and reducing ~S emissions from the seam, and details the procedures used to mine through the ~S zone in 702 longwall panel. Learning points from research and mining experience are reviewed for application in the next longwall block.

Discussion is presented of factors to be considered when selecting visualisation systems and simulators and developing interactive content to display on them. The display systems are classified into groups: monitor-based, head-mounted, large screen, large full surround screen, simultaneous real world/graphic, hand-held mobile, and holographic. Issues that are often overlooked (such as human factors, cognitive load, and development costs) and their impact on the development of sustainable simulator technologies are considered. A case study is presented based on an environmental impact simulation that examines sustainable mining methods. It is concluded that the mining industry is not taking full advantage of the available simulator technology and seems to have no formal development and integration strategy. The taxonomy is used to highlight a preferred zone of user interaction that the industry should aspire to in the design of simulators, to ensure that simulator technologies provide the maximum benefit to the user and return on investment. More efficient methods for developing virtual environments are required., Discussion is presented of factors to be considered when selecting visualisation systems and simulators and developing interactive content to display on them. The display systems are classified into groups: monitor-based, head-mounted, large screen, large full surround screen, simultaneous real world/graphic, hand-held mobile, and holographic. Issues that are often overlooked (such as human factors, cognitive load, and development costs) and their impact on the development of sustainable simulator technologies are considered. A case study is presented based on an environmental impact simulation that examines sustainable mining methods. It is concluded that the mining industry is not taking full advantage of the available simulator technology and seems to have no formal development and integration strategy. The taxonomy is used to highlight a preferred zone of user interaction that the industry should aspire to in the design of simulators, to ensure that simulator technologies provide the maximum benefit to the user and return on investment. More efficient methods for developing virtual environments are required.