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About this book

This proceedings book presents research papers discussing the latest developments and findings in the fields of mining, machinery, automation and environmental protection. It includes contributions from authors from over 20 countries, with backgrounds in computer science, mining engineering, technology and management, and hailing from the government, industry and academia.

It is of interest to scientists, engineers, consultants and government staff who are responsible for the development and implementation of innovative approaches, techniques and technologies in the mineral industries. Covering the latest advances in fundamental research, it also appeals to academic researchers.

Table of Contents


Lessons from Some Recent and Current Mine Planning Related Postgraduate Research Work at the University of the Witwatersrand

Mine planning is a very important process which is undertaken along the mine value chain. In an ideal setting, mine plans should be sufficiently robust to ensure that actual performance is as close to or the same as planned outcomes both in the short and long term. However, this is often not the case and in recent years financiers of mining projects have sometimes resorted to litigating against project proponents, claiming that they were misled into investing in projects that failed to deliver on promised outcomes. These challenges require that more research be undertaken on how robust mine plans can be generated and evaluated to reduce discrepancies between planned and actual outcomes. Accordingly, research findings towards closing the gap between planned and actual outcomes are presented based on lessons learnt from some of the mine planning related postgraduate research work that has recently been undertaken or is currently under way in the School of Mining Engineering at the University of the Witwatersrand.

C. Musingwini

Economic and Financial Risk Assessments


Economic Value Added Analysis for Mining Companies

Creating sustainable long-term value is always the aim for every mining company. However, the global mining industry finds itself in a difficult position where volatile prices, subdued markets and rising costs are forcing a short-term planning focus for survival, which may be in conflict to long-term value creation. To ensure short-term survival and long-term value creation from Mineral Resources extraction, mineral resource management (MRM) practice was developed two decades ago with an emphasis on creating optimum value for stakeholders including shareholders. MRM identifies economic value added (EVA) as the appropriate measure that integrates short-term and long-term value creation in contrast to profit; a short-term value measure. Notwithstanding EVA being a true measure of economic value, its application and reporting in the mining industry are doubtful. This paper analyzed whether mining companies have been creating true economic value for shareholders over and above the normal profit reported in income statements. EVA was calculated for four international mining companies from 2007 to 2017 and compared to reported profit. Analyses of whether mining companies have been creating true economic value for shareholders in both good and bad economic times was done. EVA has proved to be a true measure of value that mining companies should report on. This study also found that even though profit was generated by mining companies in most of the analysis period, in contrast, EVA was not created. Furthermore, it was also found that cost-cutting measures improved profit without creating EVA. In addition to the traditional measures that are always reported by mining companies, EVA should also be reported to see whether the value is being created.

T. Tholana, P. N. Neingo

Financial Risk Analysis of Optimized Ventilation System in the Gold Mine

Costs for mine ventilation are typically increasing when mines expand to deep horizons. Some underground mines in Kazakhstan still use continuously operating fans at its maximum capacity. This is not helping to save energy and costs that are in many cases very significant. However, mine safety is related to risks associated with the deficit of fresh air for mine gases dilution and removal. The ventilation system in Kazakhstan gold mine was in need of improvement because of increased production from deep horizons. The aim of this study was to analyze the financial risks associated with high-cost airflows in deep horizons of the gold mine. Mine ventilation system surveys were undertaken to develop a computerized model for simulation processes to provide with sufficient amount of fresh air deep horizons. Results of ventilation simulation were used to analyze the financial risks of the high-cost airflows. Financial simulation estimated the optimum ventilation infrastructure size, where high-cost airflows were optimized by taking into consideration the mining cost and ventilation operating costs. The result of financial risk analysis recommends implementing automated ventilation control for saving energy costs. Automated ventilation control system suggests adjusting air volume according to the necessity at varying times and areas.

S. Sabanov

Mine Development


Fundamental Study of Stope and Barrier Pillar Stabilities by Using Cut and Fill Method for Redevelopment of Rest Gold Mine, Myanmar

The stability of mine development is very important during the planned period of production. Additionally, it would be a great challenge for redeveloping rest mine project to extend the mine area due to the effect of previous mined-out area. The deposits of rest mine are usually located in deeper regions; accordingly, stress condition will be greatly changed. The existence of underground water from the previous mined-out area is also possible to infiltrate into the redevelopment of rest mine area, which will influence the stability of new openings. This paper describes the stability design of a redevelopment of a rest mine, with National Prosperity Gold Production Group Limited (NPGPGL) underground gold mine in Myanmar as a case study. This mine adopts overhand cut and fill method to extract the minerals. NPGPGL is characterized with steeply dipping vein with complex fractures and underground water, particularly during rainy season. NPGPGL has been developing stopes up to 150 m from the surface, and the mining activities are going to continue to deeper levels by introducing redevelopment rest mine project. Redevelopment of rest mine is not easy considering the instability can rise at new stope opening not only due to its own induced stress but also the effect of previous mined-out area. Therefore, suitable countermeasure arrangements are paramount to be prepared by considering the stability of stope. To determine the stability of stope and barrier pillar design of new opening, numerical simulations were carried out by using 3D finite difference software (FLAC3D).

N. Naung, H. Shimada, T. Sasaoka, A. Hamanaka, S. Wahyudi, M. Pisith

Blasting and Fragmentation


Use of Geospatial Queries for Optimum Drilling and Blasting Practices in Surface Mining

Increasing demand of the modern society for energy and raw material strengthens the role of mining in sustainable development. The basic production cycle of surface mining is initiated by drilling and blasting the material that will be loaded, hauled, and dumped by various mobile equipment. Performance measurement and analysis of all these production stages by the utilization of available technology is of crucial importance for continuous improvement of modern mine operations. Today, most of the mobile equipment used in open-pit mining have the capability to provide data related to production, positioning and machine health. Drilling equipment can be tracked by high-precision GPS systems to guide operators for the accuracy of the drill hole locations and also for comparing the drill plans and the actual drilled hole locations. Similarly, the blasting process can be managed by utilizing the data related to the amount and type of explosive charged into each blast hole. Typically, these are recorded on different environments, and each hole is named differently in each environment. As a final outcome, fragmentation of the blasted material can be investigated at multiple stages of production, such as loading, dumping, crushing, conveying, or others by using particle sizing software. However, it is challenging to derive knowledge from all of this data generated by various equipment and systems unless it is integrated for decision-making or analysis. Geospatial queries are quite effective and fast in handling geo-coordinate data and are ideal for integrating drilling and blasting data. This study introduces a systematic approach to integrate drilling and blasting related operational data collected either manually or automatically by using geospatial queries as part of integration in a data warehouse of an open-pit copper mine.

M. Erkayaoglu

Prediction of Rock Fragmentation Based on a Modified Kuz-Ram Model

The rock fragmentation is a generic term used to describe the size distribution of blasted material. Several controllable parameters as well as rock properties themselves influence fragmentation. Even though there is no method or equation that gives an exact prediction, during the past few years, numerous investigators have developed models and techniques to computerize simulation. An effective method to assess fragmentation presently is to acquire digital images of rock fragments and to process these images using digital image processing techniques. In the case of post-blast fragmentation, this is the only practical method to estimate fragmentation since screening is impractical on a large scale. The aim of this paper is to develop a model to predict rock fragmentation after blasting. For that purpose, GoldSize software was used to determine the size of fragmentation by capturing images of fragmented rock in muck piles. The resulting size distribution data was then compared with the results obtained from some prediction models such as Larsson, Kuz-Ram, and Kuznetsov. This study shows that the Kuz-Ram model has the most accurate results and is appropriate, but the confidence of the model decreases when changing the rock type. To increase the accuracy of the results, the model was modified by determination of a confidence index. The results of model verification show that the modified Kuz-Ram model can predict rock fragmentation with an accuracy of 80%.

A. Hekmat, S. Munoz, R. Gomez

Neural Network Applied to Blasting Vibration Control Near Communities in a Large-Scale Iron Ore Mine

One of the major issues in large open pit mines near communities is related to the human discomfort and possible structural damages caused by blasting vibrations. The usual approach is to determine the attenuation law based on the scaled distance and the explosive charge per delay. Recent research work conducted by different authors focus on the characterization of the local vibration attenuation law based on blasting energy, charge per delay and distance between the blasting and the monitoring points, which have allowed the determination of the maximum charge per delay for a controlled blasting. This paper provides the results of artificial neural network application to predict the blast-induced ground vibration and to allow the assessment of the environmental impact or possible structural damage, using as inputs the blastability index, the distances between the community and the blasting area, the explosive charge per delay and the blasting pattern parameters. The case study is from a large-scale open pit iron mine located at Minas Gerais state in Brazil. The methodology involves blast-induced vibration monitoring, the design, training, validation and testing of a neural network, and the control of the ground vibrations by controlling the maximum charge per delay. The results obtained in the network development phases have provided satisfying correlations between the predicted and measured values, with the values of R2 ranging from 0.8512 to 0.9639 in the different network development phases.

N. Torres, J. A. Reis, P. L. Luiz, J. H. R. Costa, L. S. Chaves

Design, Planning and Optimization of Surface and Underground Mines


Comparison of Different Approaches to Strategic Open-Pit Mine Planning Under Geological Uncertainty

Uncertainty has been a main topic in mine planning research during the last decade. Several models have been proposed to address and incorporate the uncertainty in the strategic mine planning process, to generate a better, more profitable plan even in adverse conditions such as geological or metal price uncertainty. Among these models, in the general two-stage approach, the extraction is usually the first-stage decision while processing considers the uncertainty as a second-stage decision. Another option is to minimize deviations from production targets (ore, average grade, and contaminants) considering the uncertainty in the grade of the deposit, or the risk averse approaches where some risk measure is introduced to minimize the losses in unfavorable scenarios. However, it is not clear how these models perform comparatively since they often consider the uncertainty in a fundamentally different way, with different objectives functions, constraints and uncertainty modeling. Therefore, there are no general guidelines under which conditions some approach is better than other. For this reason, this works aims to compare two of these proposed models (two-stage and minimization of deviations) under the same conditions, to verify the advantages of each one of them and generate recommendations about the applicability of these approaches. This comparison is performed considering the production plan, the distribution of the net present value, the total deviations from the target, among other indicators.

G. Nelis, N. Morales, E. Widzyk-Capehart

Use of Genetic Algorithms for Optimization of Open-Pit Mining Operations with Geological and Market Uncertainty

In the planning of any mining operation, the main objective is the maximization of the profits. However, at the moment of performing this task, a series of assumptions are made, which, in some cases, are far from reality, such as the estimation of the sale price and the ore concentrations inside the deposit. In the present paper, a stochastic optimization model based on genetic algorithms is proposed in conjunction with Monte Carlo simulation, where it is possible to include and measure the risk to which open-pit mining operations are exposed for a polymetallic deposit, having as main objective maximizing the net present value for a specific risk level. Among the main results of the investigation, it was determined that the optimal production scheduling does not result in the longer life of mine. This can be attributed to the accumulated uncertainty that occurs as the life of mine increases.

G. Franco-Sepulveda, G. P. Jaramillo, J. C. Del Rio

Optimisation of Mining Block Size for Narrow Tabular Gold Deposits

The geological block model is used as the basis for the grade-tonnage curves and subsequent financial models. On some narrow tabular gold deposits, these blocks are observed to be significantly smaller than the smallest block that can be selectively mined. The effect of this on the financial model is not clear. This paper explores how differences in the mining block sizes affect the financial model. Monte Carlo simulation is used to create a series of hypothetical, narrow tabular gold deposit databases with a range of average grades at either side of the assumed cut-off grade. EXCEL, as well as Leapfrog Geo, software is utilised to create geological block models with a range of sizes. Grade-tonnage curves are created for each model and the assumed cut-off grade is applied to determine the resultant tonnes and average mining grade above cut-off grade. Financial models created by these are compared to determine how critical it is to have the mining block model dimensions similar to the smallest selective mining unit. It is shown that there has to be a broad similarity in the dimensions of the blocks used for planning purposes and publishing grade-tonnage curves and financial projections when considering the EXCEL model. This trend is, however, not observed when considering the grade-tonnage curves created from the Leapfrog Geo generated model. This model is considered to be a more reliable approximation of how grades are extrapolated into blocks and show how the theoretical EXCEL generated model has a higher resolution than is realistically possible when considering sample spacing. The financial outlook for the hypothetical mines can also be altered by changing the mining method to change the selectivity of the ore body.

C. Birch

Methodology to Optimize and Sequence the Semiautomated Ramp Design in Underground Mining

There are few optimizing methodologies that may guide the process of ramp design in underground mining; they contemplate designing the accesses and then completing the mine exploitation schedule, which does not reflect the development costs in the NPV of the project and relies on the engineer’s knowledge. The methodology presented in this paper focuses on the assisting the ramp design in underground mining using an optimization model that gives the operational costs associated with the accesses, during the development and the operation of the mine. Additionally, a sequence of construction is obtained as a complement of the design with a scheduling software. The methodology aims to obtain a design and sequence of the ramps and crosscuts configuration considering initial parameters that must be entered the optimization model such as production levels, maximum slope, curvature, construction costs, and transportation costs, among others. After applying the optimization model, the result is the identification of the points belonging to the ramp design, the ramp construction, and operation sequence and the total cost associated with the project. This result must be refined using CAD software to obtain the final configuration. When this methodology is applied to a case study, a gold and silver mine exploited using the Bench & Fill method, the results show that the optimization model can replicate the design obtained by the prefeasibility study of the project and provide additional design options that can reduce the total cost. The methodology provides operationally feasible solutions and can be used as a guide for the design of ramps in underground mining while reducing the time allocated to these tasks and delivering more than one design according to the initial parameters.

S. Montané, P. Nancel-Penard, N. Morales

Production Scheduling in Sublevel Caving Method with the Objective of NPV Maximization

Production scheduling optimization is one of the main issues that have a significant effect on the mine economics. Production scheduling optimization in underground mines, has received less attention than in surface mines, and it is still a manual process and in most cases, achieving the truly optimal result through manual scheduling is impossible due to the complexity of the scheduling problem. Caving methods compared with other underground mining methods are low-cost methods and have high production rates. Sublevel caving is one of the main underground mining methods for hard rock mining and there are limited studies about its long-term production scheduling. In this paper, an integer linear programming (IP) model with the objective of net present value (NPV) maximization is developed for production scheduling that is suited for sublevel caving method. The model contains acceptable technical and operational constraints. This model is formulated two-dimensionally (2D) and it can optimize production schedule in thin-layer deposits. In this research, MATLAB programming platform was used to capture the IP model framework. The model was applied on a real block model and the maximum NPV is determined. With respect to determining maximum NPV, it is recommended that the mine development should be determined based on the optimal mining sequence.

M. Shenavar, M. Ataee-pour, M. Rahmanpour

Generation of a Monthly Mining Development Plan for Underground Mines Using Mathematical Programming

Mine development is necessary to enable all required infrastructures to begin production in a mine sector or to give support for the productive sector. The development plan is subject to constraints, making the planification process highly time and computationally consuming. From a mathematical point of view, this is an optimization problem in which the objective function is the execution time of mine development, considering a given time horizon. In this paper, a methodology is proposed, which allows to resolve the time optimization problem for underground mine development, minimizing the execution time and considering operational, geotechnical, and deadline constraints. The case study is based on an underground mine extracted by panel caving method. A mathematical model is based on mixed-integer programming in which several activities are scheduled and sequenced in a given time horizon, independent of the extraction method. The results show an executable development plan within a 12-month period fulfilling each of the restrictions raised in the problem. The proposed methodology considerably reduces the time of the development plans allowing to consider different scenarios before the final execution plan is selected.

V. Rojas, T. González, N. Morales

Optimization of Coal Production Rate as a Function of Cut-Out Distance

Current innovations and technological advances in underground coal mines have contributed significantly toward sustainable extraction and productivity. However, equipment such as the continuous miner is highly underutilized due to spatial restriction and suboptimal practices. Support systems such as the cut-out distance and panel dimensions can be optimized to maximize equipment utilization and consequently increase the production rate. This paper implements an ad hoc analytical framework to evaluate and determine the optimum cut-out distance for maximum coal production. The objective of this work is to determine the optimum cut-out distance, panel width, and fleet size for maximum coal production. A real room and pillar coal mining system were evaluated using discrete event simulation. The results show that for the system evaluated an 11-entry panel width with a fleet size of three shuttle cars is optimum for the variable cut-out distances examined. The utilization of the continuous miner and production rate increases by 6% at a maximum cut-out distance of 12.19 m.

A. Anani, W. Nyaaba, A. Hekmat

Analysis of the Impact of the Dilution on the Planning of Open-Pit Mines for Highly Structural Veined-Shaped Bodies

Currently, mining exploration is finding more small and thin deposits than massive copper porphyries. Therefore, vein deposits are becoming increasingly important in the mining business. A challenge presented by these ore bodies is the incorporation of operational techniques and practices that allow achieving sufficient selectivity to make the project profitable, not to mention that in certain geological contexts the structures present contaminants, which may create problems even for profitable operations in later stages. For this purpose, dilution should be treated as a fundamental factor, subject that in the current industry is little studied. The objective of this paper is to measure the impact of dilution in the planning of open-pit mines for highly stratified and veti-shaped bodies. For this, the following methodology is used, by means of a study of a fictitious deposit. First, a study is carried out on the dilution, its impact and ways of quantifying it in the industry. Then, several scenarios of different average grades are generated in the host rock, in addition to support changes, to verify the impact on a broad spectrum of cases, the proportions of the mineral in contact with waste are then indicated, thus quantifying the amount of resources to be diluted, followed by long-term planning, where the results of the proposed cases are finally collected and analyzed through key technical and economic indicators. It was found that as the block size increases, the contact surface between ore and waste increases, reducing the amount of ore without risk of dilution and, in the same way, reducing the waste, albeit in a smaller proportion. Finally, applying planning restrictions of blending and allowing a maximum dilution, there is a trade-off between the risk of diluting the resource and the value of the plan.

R. Amirá, N. Morales, A. Cáceres

Modeling Optimum Mining Limits with Imperialist Competitive Algorithm

Design process for open-pit mines starts with determining ultimate pit limit (UPL) that includes the maximum profit. There are different methods to determine the UPL, including manual and computer methods. Computer-based methods are categorized to intelligent and mathematical methods. Intelligent-based methods are based on computational intelligence. Among the algorithms based on computer calculations, one can mention the dynamic programming algorithm and graph theory while algorithms, based on computational intelligence, include genetic algorithm, ant colony optimization, etc. This paper introduces the application of a new approach called the imperialist competitive algorithm (ICA) in UPL optimization. The ICA algorithm is considered as an intelligent algorithm that starts with a series of initial countries; these countries are input to the problem and improved in the next steps help or improve the solution. For UPL optimization problem, the initial pits, formes empires and lucrative pits select as imperialist. Two policies, called attraction and revolution, are used to enhance the solution. The solution given by this algorithm was compared with the response of the dynamic programming algorithm. The results are quite promising.

S. Javadzadeh, M. Ataee-pour, V. Hosseinpour

Application of Particle Swarm Optimization Algorithm to Optimize Stope Layout for Underground Mines

After the exploration phase, data collected are analyzed and interpreted using geostatistical modeling techniques to produce an orebody model. The orebody model is delineated into thousands of mining blocks in 3D space with assigned grade values. The geological information will inform the type of mining to be adopted, whether surface or underground mining. Consequently, the appropriate mining method is selected depending on the type of deposit. It is at this stage that mine planners can commence with the generation of an optimal stope layout subject to economic and technical constraints. The selection of an optimum stoping layout is one of the important areas of mine planning; however, it is still relatively underdeveloped. There are several algorithms that have been developed to generate a stope layout for underground mining. However, none of these algorithms guarantees an optimal solution in 3D. PSO has not been applied to the stope boundary problem, although its principles are amenable to the 3D environment. This begs the question: can the PSO algorithm generate an optimum 3D underground stope layout? This paper refers to part of an MSc research study undertaken at the University of the Witwatersrand.

T. M. Mmola, A. S. Nhleko, J. M. Atherfold

Open-Pit Mine Production Scheduling: Improvements to MineLib Library Problems

Scheduling the extraction and the production in an open-pit mine with the goal of maximizing the net present value of the operation has been accomplished to date using various approaches including the use of mixed integer linear programming techniques. Since realistic models could have very large number of variables and constraints, the combinatorial optimization problem of finding an optimal, or at least, good feasible extraction schedule maximizing profit is computationally complex and difficult. It is also challenging to confirm whether various algorithms are addressing the same problem and are based on the same assumptions. The publication of MineLib, a library of test problem instances for open-pit mine production scheduling problems, namely the Constrained Pit Limit Problem (CPIT) and the Precedence Constrained Production Scheduling Problem (PCPSP), has provided new ways to address the scheduling in open-pit mines. In this paper, a full-binary formulation for PCPSP is proposed. The application of a sliding time window heuristic combined with a block preselection procedure to maximize the net present value in open-pit mines is tested on 10 PCPSP instances from MineLib library showing significant improvements over the previously reported results. In addition, the current state of the MineLib library, showing the best-known results for CPIT and PCPSP, is described for completion.

E. Jélvez, N. Morales, P. Nancel-Penard

Mining Equipment Selection Innovative Materials Handling Systems and Equipment


Development of a Computer-Aided Dragline Selection Program

Selection of appropriate machine and equipment is one of the most critical tasks required in surface mining. Since draglines are massive and expensive machines, their selection is of paramount concern to mining engineers and decision makers. The selection of appropriate dragline model requires simultaneous consideration of various parameters, such as geological properties of overburden material, stripping method, available fund, and technology. Therefore, this is a complex and time-consuming process. In this study, the dragline selection process was reviewed and a computer-aided selection program, Draglayout, was developed to increase the efficiency in the selection process. The developed software suggests list of the commercially available dragline units based on its maximum suspended load and reach factor which are compatible to achieve the given stripping and production targets. The selection process consists of four main stages as: initial estimations of dragline operation parameters (availability, dragline utilization, dragline operating hours, cycle time, ore production, ore recovery, etc.), defining initial mine design geometry, available equipment geometry, and mine design relations, reviewing the above steps and selecting the dragline.

S. Akhundov, N. Demirel

Optimal Selection and Assignment of Loading Equipment for the Compliance of an Open-Pit Production Plan

Open-pit mining is a resource-intensive process since the profitability of the business is strongly related to the magnitude of the tonnage extracted. Therefore, it is necessary to use large equipment to extract and transport material from the mine. The decision of what and how much equipment to buy and where it should be operating, strongly impacts the value of the mining business. Generally, the estimation of the material movements is made using various planning software based on a movement capacity of certain material in tons extracted per day, which does not necessarily represent what happens in the operation. In this paper, a multi-objective optimization model is presented, which aims to determine the optimal shovel-bench allocation for the operation and also show that the equipment allocation obtained can estimate a production plan that fits the reality better than the conventional methodologies. Several operational factors and restrictions are considered including mechanical availability, utilization, space restrictions, and precedence among benches of different pushbacks. Divers experiments were carried and for all cases, and fluctuations were obtained in the tonnages extracted per month that were not predicted in the mine plan with a production defined by a constant flow of tons. The presence of these fluctuations can indicate that a greater number of variables can still be considered within the planning that could allow building of more robust plans to guarantee a reliable operation in terms of production and feed to the plant.

H. González, N. Morales

A Transportation Problem-Based Stochastic Integer Programming Model to Dispatch Surface Mining Trucks Under Uncertainty

Over the last 50 years, several truck allocation and dispatching decision-making models have been developed in the field of surface mining operation optimization. Despite the stochastic approaches toward truck allocation problem, the researchers have not considered the effects of random parameters on truck dispatching problem. However, most of the factors affecting the truck dispatching decisions are random in behavior such as truck travel time to the next destination. This paper develops a truck dispatching decision-making model based on the transportation problem approach. The developed model is a stochastic integer programming model that makes decisions on the trucks dispatching problem under the condition of trucks’ travel time uncertainty. Besides, a simulation model of an open-pit mining operation has been developed to evaluate the developed stochastic truck dispatching model. Results of the implementation of the developed model prove impacts of the randomness in the operational parameters on the truck dispatching decisions.

A. M. Afrapoli, M. Tabesh, H. Askari-Nasab

A Discrete-Event Simulation for a Truck-Shovel System

Computer-based truck dispatching systems are widely used to improve equipment utilisation and productivity in open-pit mines. Such systems should be based on models that reflect the realistic operation of a truck-shovel system and utilise a suitable simulation tool. In this paper, a discrete-event truck-shovel simulation model, referred to as Truck and Shovel JaamSim Simulator (TSJSim), was developed. The TSJSim simulation model may be used to evaluate the Key Performance Indicators (KPIs) of the truck-shovel mining system in an open-pit mine. TSJSim considers a truck as an individual traffic vehicle unit that dynamically interacts with other trucks in the system as well as other elements of the traffic network. The developed model provides the capability for evaluating the impacts of bunching, intersection traffic management and truck-allocation strategies on a surface mine truck-shovel system. The model can also be used to estimate the optimal truck fleet size for the entire truck-shovel network within a mine.

E. Y. Baafi, W. Zeng

Increasing the Productivity of the Transport Fleet by Reducing the Carryback Load

This work aims to demonstrate the gains with the productivity of the transport fleet through the reduction of the carryback load. Material retention occurs mainly due to the high humidity of the material being transported and materials with a high content of alumina and manganese. The technology used to reduce retention of material in the trucks’ bed will be the heated dump system. The system uses the exhaust gases themselves from the combustion of the engine diesel to heat the floor bed, and consequently release the material that ends up stuck. This technology was tested in a truck of the fleet and its results were relevant, there was a significant reduction in the volume of retained mass compared to another truck of the same model. The deployment of this technology throughout the company’s transportation fleet can result in a 1.8% increase in its productivity and 0.76% in its effective use.

W. Felsch, M. das Graças Silva, C. Arroyo, M. Vinicius Baeta, A. C. Souza, R. Fonseca, A. Curi

Environmental Comparison of Different Transportation Systems—Truck-Shovel and IPCCs—In Open-Pit Mines by System Dynamic Modeling

The environmental challenges in mining activities are one of the most important concerns in mining design, and in some extent that planning without considering environmental issues cannot be an optimized one. The transportation system in mining projects, which is counted as one of the most significant parts of mining activities, is evaluated as one of the sources of environmental problems. Accordingly, in this paper, common transportation equipment in mines, which are trucks and conveyor belts, are evaluated in different types of transportation systems, i.e., Truck-Shovel, Fixed In-Pit Crushing and Conveying (FIPCC), Semi-Fixed In-Pit Crushing and Conveying (SFIPCC), Semi-Mobile In-Pit Crushing and Conveying (SMIPCC), and Fully Mobile In-Pit Crushing and Conveying (FMIPCC) systems. The environmental index, which is the indicator of the environmental condition while using each transportation system, is introduced and compared in these systems. System dynamics modeling, as a powerful tool for simulating the behavior of a system through the time, is used to model the transportation system of an open-pit mine. For this, different variables and their connections in the system are described. It was shown that these transportation systems differently behave in the case of environmental index such that FMIPCC stood in the first rank while the Truck-Shovel system was ranked the fifth. System dynamics modeling can be utilized in the making decision process, which the planners want to evaluate the behavior of the system in different scenarios. This method is capable to give an insight into the current and future state of the system for any alternative.

H. Abbaspour, C. Drebenstedt

Truck-and-Loader Versus Conveyor Belt System: An Environmental and Economic Comparison

The oscillation of the main mining commodities prices and the significant increase in the operating costs has forced this sector to look into processes that are more and more efficient. The transportation costs in an open-pit mine operation can account for 40–60% of the total costs. The objective of this study was to carry out a comparison between two ore transportation methods: conveyors and haul road trucks. A state-of-the-art assessment was carried out, as well as a case study applied to a large iron ore mine located in Brazil. The main advantages identified in the use of conveyor belts were the lower exposure to the risk of accidents and the ability to overcome high angles. On the other hand, trucks had high operating flexibility and lower Capex. Also, with this study, it was possible to conclude that the conveyor belt system has lower CO2 emission levels, has lower operating costs, and consumes less inputs than the system with trucks, which, on the other hand, generates less solid waste.

C. M. de Almeida, T. de Castro Neves, C. Arroyo, P. Campos

How to Exit Conveyor from an Open-Pit Mine: A Theoretical Approach

Nowadays, the giant open-pit mining operation is to be continued in a more remote and difficult part of the ground. Transportation is the most challenging and costly task in such situations. It accounts for more than 50% of total operating and capital outlay. Among the current transportation alternatives, the conveyor is the best from operating cost and sustainable development points of view. The conveyors should be designed in the way that imposes the lowest cost to the project. The exit method of conveyors from the pit is one main design element which significantly influences the conveyor cost. There are a few methods by which the conveyor system can exit from the pit. Dedicated ramp slot (DRS), the existing ramping system (ERS), tunnel and high angle conveyors (HAC) are these alternatives which are not extensively studied in the past. In this paper, a theoretical foundation is developed to analyze the cost of alternative schemes. Besides, the basis is able to determine the break-even points between the alternatives. In the base case, our computational results indicate that the net present cost of DRS is the lowest possible up to 140 m depth, while afterward the HAC has the lowest net present cost.

M. Paricheh, M. Osanloo

Bulk Material Volume Evaluation and Tracking in Belt Conveyor Network Based on Data from SCADA

Belt conveyors are commonly used for continuous transportation of bulk materials in both opencast and underground mines. Depending on the mine, the network of conveyors might be complex and transport of material from point A to point B can be done in several ways. Systems usually are overestimated—conveyors can transport much more material than they currently do. Recently energy-efficient solutions are expected in mining companies. Obviously, effective transport of material from mining face to mineral enrichment plant on the ground is a complex task that has to take into account production plans, maintenance of conveyor network, bunkers capacities, shaft output, etc. In order to optimize the operation of conveyor network, we need detailed information about the structure of the entire system (including inputs and outputs) and material volume in time and space. Nowadays, scales in the underground infrastructure are installed in predefined places, and serve for production volume identification, rather than for detailed ore flow tracking. In this paper, we propose a unique procedure that could estimate weight of material stream on the belt using electric current data. Such an approach will allow to estimate the amount of transported material in a more detailed way, providing more continuous information regarding the entire conveying system. Accuracy of proposed technology is c.a. 95%. Having precise information about ore volume in time and space, we could visualize bulk material stream in the system, and ultimately it will be possible to build a model for advanced what-if conditional analysis and simulations.

P. Stefaniak, P. Kruczek, P. Śliwiński, N. Gomolla, A. Wyłomańska, R. Zimroz

Haul Productivity Optimization: An Assessment of the Optimal Road Grade

Global mining companies’ strategies have been focused on production costs reduction to overcome the current global iron ore economic scenario, characterized by slower growth in the Chinese market and floating iron ore prices. The economic mine feasibility is directly related to its stripping ratio and high productivity of haulage equipment, as it represents a significant part of production costs and resource allocation. Since that route grades are relevant geometric parameters to stripping ratio and haulage equipment productivity, this study presents the productivity maximization based on the optimal value of grade in a Quadrilátero Ferrífero mine, using Lindo® What’s Best software. The optimization geometric assessment was carried out using Maptek Vulcan® software that has measured the pit geometries and stripping ratio impacts. The results have indicated transport productivity improvement with minor grade access variations, which although have increased the cycle time, they have decreased the total traveled distance with a total cycle time positive effect. The geometric analysis has shown an ore releasement increase of 2–7%.

V. F. Navarro Torres, J. Ayres, P. L. A. Carmo, C. G. L. Silveira

Waste Disposal


Sensitivity Analysis of Mechanical and Geometrical Properties of Fly Ash Stabilized Overburden Dumps Using Mathematical Simulations

Increasing stripping ratios in surface mines have led to the removal and movement of huge volumes of overburden that is generally stored in form of internal or external dump within the mine boundaries. For safe storage in limited areas, the overburden dumps are stabilized using several popular methods. One of the recent economic and environmentally safe techniques is the stabilization of dumps using fly ash composite material. This study analyzes the sensitivity of the overall stability of the dump slope on its geometrical and material properties, when stabilized using fly ash composite. Four different geometric parameters and six material properties were varied in simulated dump models to find the sensitivity of the factor of safety (FOS) using limit equilibrium (LEM) and finite element methods (FEM). The sensitivity analysis was also carried out for minimum thickness of fly ash composite layers required for better stabilization of dump slopes. From the study, it was observed that FOS of the dump slope was most sensitive to the material properties of overburden, apart from the slope angle, dump height, number of fly ash layers, and cohesion of fly ash composite (Sensitivity Index (SI) > 0.2), while it was less sensitive to other geometrical parameters and material properties. The critical composite layer thickness was found to be most sensitive to all the geometrical parameters, but very less sensitive to the material parameters (SI < 0.1). These sensitivities give a clear idea of the criticality of various parameters for a stable dump slope design.

T. Gupta, M. Jamal, M. Yellishetty, T. N. Singh

Rock Mechanics and Geotechnical Applications


Three-Dimensional Integral Modeling of Large Open-Pit Slopes: An Innovative Stability Analysis

The slope stability analyses in large-scale iron ore mining are usually conducted using two-dimensional models. Although this methodology helps to interpret the hydro-geomechanical behavior of open-pits, it might not capture the great complexity associated with mining environments. The geological formations associated to ore deposits may present complex spatial distribution of lithologies and ore grades as well as mechanical/hydraulic behaviors and properties. The distribution of lithologies and the ore grades are sufficiently well represented in the mining block model. However, the geotechnical model usually lacks reliable estimations of the properties and geologic structures due to the inherent complexity of this environment. Thus the block model appears as a potential vehicle for incorporating the geotechnical data and feeding some mechanical analysis routine to perform stability analysis in an integrated way. In this paper, we present some results of a FLAC3D model fully implemented using Python programming developed in the IPython console embedded in the FLAC3D 6.0 environment. The Numpy and Scipy libraries are used to fasten the calculations. The rock mass behavior is represented using the Mohr–Coulomb, generalized Hoek–Brown and Ubiquitous joints constitutive models according to the lithology. GSI is interpolated based on the borehole locations, and the properties of the intact rocks are considered homogeneous for each lithology. The attitude of the weakness planes considered in the ubiquitous model is attributed according to the structural domain discretization previously observed in the field. A case study of an iron ore mine of the state of Minas Gerais in Brazil is also presented. Some results of the stress–strain are presented. This promising tool is still under development to account for monitoring-based self-calibration.

G. F. Napa-García, V. F. Navarro Torres, I. R. Trópia, R. B. Capelli, T. R. Câmara

Collocated Ground Deformation and Pore Pressure Measurements in Open Pit Mines: Laboratory Testing and Analysis of Wireless Sensing Platform

The assessment of subsurface deformation and variations in pore pressure inside the rock mass still present many challenges: limited number of devices installed within the boreholes, technical limitations related to installation and to the data acquisition system or limited number of collocated measurements of displacement and pore pressure. Thus, the ability for real-time, in-ground, wireless data acquisition and processing of subsurface deformation and pore pressure with a large number of collocated measurements represents a unique opportunity toward better understanding of the rock mass behavior and its effect on slope stability. Currently, extensive laboratory-scale experiments of the prototype wireless Geo4Sight sensor for deformation and pore pressure in-ground measurements are being undertaken to assess the measurements´ accuracy over prolong period. In situ temperature and magnetic properties of the rock and water salinity influence have also been tested. Stability testing at constant temperatures over extended period showed highly correlated changes in tilt direction and extent with reasonably constant errors over time.

E. Widzyk-Capehart, A. Barberán, M. J. Briceño, C. Navarro, P. M. V. Nguyen, C. Opazo, S. Steffen

Determination of the Crown Pillar Thickness Between Open Pit and Underground for Coal Mining

Open pit mines cannot increase continually its depth of exploitation due to costs, safety, environmental and social expectations. In fact, many open pit mines have either already made the decision or are at the planning stage to change their mining activity from open pit to underground to remain competitive. In OP-UG transition, determining the adequate thickness of a crown pillar is one of the most essential challenges to address. Limited research has been carried out in this area, with the majority applied to the metalliferous ore deposits. This paper presents a new approach to the determination of the crown pillar thickness between Open Pit and Underground mines for coal mine deposit based on the prevention of water inrush through failure zones induced by underground operation (longwall mining). An overview of the studies conducted to-date in determining the crown pillar thickness is followed by a series of numerical modelling studies using finite difference software FLAC with selected variables including rock mass properties and depth of coal seam deposition. At the conclusion of the paper, brief guidelines for determination of crown pillar thickness between Open Pit and Underground mines are presented.

P. M. V. Nguyen, E. Widzyk-Capehart, Z. Niedbalski

Identifying Geochemical Anomalies Associated with Cu–Mo Epithermal Mineralization Using PCA and Concentration–Area Fractal Modeling in the Heris Belt, East Azarbaijan (IRAN)

The Heris Belt is recognized as an important Cu polymetallic mineralization belt in the north of Iran. Recent field studies show that polymetallic epithermal deposits are one of the significant deposit types in this area. In this paper, principal component analysis (PCA) and concentration–area (C–A) fractal modeling are used to identify geochemical anomalies associated with Cu and CU–Mo mineralization based on Cu, Mo, As, and Sn stream sediment data. In this study, enhancing and separation of geochemical anomalies using the classic method and fractal method by use of concentration–area (C–A) was conducted at the Heris Cu deposit, NW of Iran. Log–log elemental plots fitted with lines show concentration–area (C–A) correlation of Cu, As, Sb, and Mo. By use of concentration–area fractal method, especially in stream sediments, can provide the appropriate response for separation of populations. In this research, the geochemical data of Khajeh (5366) 1:100,000 sheet, where is located in the SE of East Azarbaijan, were used for detection of anomaly areas of elements. Therefore, the one variable statistic evaluation was used for these elements. In the next step, background populations and anomalies were separated by drawing C–A logarithmic curves. After that, the symbolic map of anomalous type of each element was drawn using ArcGIS 10.3 software and multifractal inverse distance weighted method. After that, PCA was used to combine these elements concentration values and finally C–A analysis was used to decompose the best component pattern obtained by the PCA. The results indicated the presence of major anomalies in the center and south regions that was based on sub-surface igneous rock units and around NE–SW. Finally, we find the Heris Belt potentially hosts undiscovered Cu and Sb Epithermal deposits, and the integrated anomalies for Cu, Mo, Sb, and As occurring around the intrusions and in the vicinity of faults in the center part of the Gangdese Belt should be further investigated in the next step of mineral resource exploration.

M. Safari, M. Manouchehryniya, M. Barikany

Numerical Simulations of Geomechanical State of Rock Mass Prior to Seismic Events Occurrence—Case Study from a Polish Copper Mine Aided by FEM 3D Approach

The biggest risk to operations in Polish copper is high-energy seismic tremors where hypocenters are located within the main roof strata. These phenomena occur often in the areas which are virtually free of tectonic disturbances. They are extremely difficult to both predict and analyse due to their short duration and unpredictable time of occurrence. The objective of the presented analysis was to determine the overall stress/deformation states within the considered mining panel prior to the selected archival seismic event and afterwards to judge how the progress of mining could affect the occurrence of instability in the roof strata rock mass. Geomechanical problem solution and results visualization were based on the NEi/NASTRAN computer program code utilizing FEM in three dimensions.

W. M. Pytel, P. P. Mertuszka, T. Jones, H. Paprocki

Seismic Hazard Prediction Using Passive Seismic Tomography in Polkowice-Sieroszowice Copper Ore Mine, SW Poland

Rock bursts pose the prime threat in underground copper ore mines in Poland. The rock mass, whose initial mechanical balance is disturbed by exploitation works, accumulates energy and then releases it rapidly. As a consequence, spontaneous seismic events are induced, which are hazardous. Therefore, the forecasting of seismic hazard is crucial for work safety. Many methods are used to assess this threat. Unfortunately, they can describe only the situation after seismic events. Passive seismic tomography allows to predict, to some extent, the location of energy accumulation. On the basis of seismic events occurring in a given period, it is possible to determine zones, which during the future mining, may comprise increased seismic activity. It has been found that hypocenters of strong shocks are most often associated with high velocity of P wave. However, in low seismicity zones, low velocity is observed. The aim of the study is to determine the effectiveness of the passive seismic tomography in the prediction of seismic hazard. The results of the tomography were analyzed in relation to the energy, number and location of seismic events which occurred several months after tomographic calculations. The key term here is the prediction, which is understood as the forecast of the place, time and strength of a seismic event. The accuracy of predicting the stress distribution by means of the seismic wave velocity and seismic anomalies was assessed. The increase in seismic wave velocity means the increase in the strain of rock mass and seismic hazard. The calculated distribution of the P wave velocity allows one to identify seismic hazard zones and monitor their changes. The effectiveness of seismic hazard forecasting was assessed for one mine division of the Polkowice–Sieroszowice mine in 10 years and the relationship between seismic activity and seismic anomaly as well as P wave velocity was determined.

A. B. Gogolewska, D. Smolak

Modeling Permeability Filtration in Outburst Zones

The aerodynamic model of a mine ventilation network including face space of preliminary development has been developed with the use of quasi-analog simulation analysis of the object, based on consideration of a multistage nature of gas dynamics. The model allows finding: solutions to permeability filtration of gas in outburst zones of face spaces, equivalent aerodynamic characteristic of sudden gas outburst; distribution of discharged gases between mine openings and finding zones and openings where fan reversal and accumulation of methane of explosive concentration is possible. This paper addresses the modeling of permeability filtration of gas in outburst zones of coal mine face spaces.

R. Khojayev, R. Gabaidullin, S. Asainov, I. Filatov

Maintenance and Production Management for Mines and Mining Systems


Predictive Maintenance of Mining Machines—Problem of Non-Gaussian Noise

Predictive maintenance has been recognized by companies as a promising approach for reducing machine operation costs. It could be done in online and offline mode. In any case, the key issue is how to process acquired data, how to interpret diagnostic features, and how robust the final decision is. Unfortunately, in case of mining machines, classical diagnostic techniques used commonly in various applications often fail in the sense of false alarms, lack of detection, etc. The problem has been first recognized as an influence of time-varying load/speed conditions. Recent research done for mining machines showed that one might obtain misleading results due to contamination by non-Gaussian and impulsive noise as well. Source of such non-Gaussian noise could be related to process (mechanical excavation, crushing, milling, etc.) or natural operation of the machine (compression, pumping), can be transmitted to the sensor from other machine operated nearby, and might have purely random, accidental nature, etc. In any case, one needs appropriate tools to process such noisy data. According to our experience, a good example to illustrate the problem and one of the most challenging machines is the copper ore crusher, where regime of work produces impulsive noise related to falling pieces of ore into crusher, as well as crushing process. Classical methods based on the detection of impulsivity will not provide satisfactory results. One needs to take into account cyclic nature of fault-related signal. For this class of diagnostic problems, we have developed a set of tools that is based on alpha-stable (heavy-tailed in general) distribution. Framework for localized damage detection in gears or bearings is as follows: we use time–frequency decomposition of the vibration signal to obtain set of sub-signals with simplest structure instead of one complex signal. Extracted time series from each of the frequency bands can be analyzed separately in the context of impulsive and cyclic nature. We have adopted advanced modeling techniques defined for signals with heavy-tailed distributions. We are able to identify so-called informative frequency band (to asses which sub-signals are informative) and identify cycle/period of disturbance by generalized measures of dependence for heavy-tailed signals (codifference, covariation, Fractional Lower Order Covariance—FLOC). Note that due to impulsive character of the signal, one cannot apply methods requiring finite variance (autocorrelation should not be used). Thus, authors proposed to apply appropriate counterparts for heavy-tailed data. In this paper, we will summarize the proposed approach and present the latest examples of applications to vibration data from mining machines.

G. Żak, A. Wyłomańska, R. Zimroz

Predictive Maintenance of Mining Machines Using Advanced Data Analysis System Based on the Cloud Technology

Nowadays, mines become more and more innovative and computerized. The operational conditions are harsh and varying; therefore, appropriate and powerful tools have to be applied. Typical mines possess huge infrastructure, which consists of various types of machines and devices, i.e. roadheaders, load–haul–dump (LHD) machines, belt conveyors, hoisting machines and others. Predictive maintenance is a crucial aspect in the proper mine operation; it creates opportunity for early damage detection and planning repairs for the most suitable period. However, the number of objects that need to be maintained is massive. Thus, proper maintenance is a challenging task. Due to rapid development in the field of instrumentation and cloud computing technology as well as the significant growth in predictive maintenance for industrial applications, it is possible to use multi-source information data fusion to carry out large-scale condition monitoring systems. Different approaches for the data gathering can be applied: stationary and portable systems or highly innovative mobile inspection robots. Recently, the European Union recognized the need to invest in robotics, automation, industrial Big Data and other new technologies in order to improve the heavy industry including mining industry development. In this paper, the application of the cloud computing technology in predictive maintenance for data mining and analysis is presented. The results show that cloud technology can highly boost mine operation and provide useful diagnostic and managing information.

P. Kruczek, N. Gomolla, J. Hebda-Sobkowicz, A. Michalak, P. Śliwiński, J. Wodecki, P. Stefaniak, A. Wyłomańska, R. Zimroz

Condition Monitoring for LHD Machines Operating in Underground Mine—Analysis of Long-Term Diagnostic Data

Load–haul–dump (LHD) machines are key assets in horizontal transportation in the underground mine. They perform ore haulage from mining faces to the nearest belt conveyors, dumping the material at the specific locations. Their operation can be described as cyclic. For maintenance staff of those machines, effectiveness-related demands are the greatest challenge, especially taking into consideration harsh and time-varying environmental conditions. The analysis of long-term data recorded on such machines can provide information about the changes in technical condition of the machine. Moreover, such observations can allow to track slowly progressing changes in technical condition that are effectively impossible to asses given only short-term measurement data. Besides the context of analyzing such data, it can be used as large-scale training dataset carrying a lot of useful information for the future development of diagnostic procedures. In this paper, authors propose statistics-based methodology for the analysis of long-term observations of diagnostic data recorded on LHD machines. Fusing information contained in various types of diagnostic variables (i.e., temperatures, pressures, operational parameters like engine rotational speed, torque, etc.) can allow to unravel underlying degradation processes occurring in the machine, with greatest focus on drive-related components.

A. Michalak, P. Śliwiński, T. Kaniewski, J. Wodecki, P. Stefaniak, A. Wyłomańska, R. Zimroz

Enhanced K-Nearest Neighbors Method Application in Case of Draglines Reliability Analysis

Dragline’s availability plays a major role in sustaining economic feasibility and operation of opencast coal mine. Thus, its reliability is essential for the production availability of mine. The dragline’s reliability and maintenance optimization are key issues, which should seriously be considered. Draglines’ unexpected failures and consequently unavailability result in delayed productions and increased maintenance and operating costs. The applications of methodologies which can predict the failure mode of dragline based on the historical dataset of failure are not only useful to reduce the maintenance and operating costs but also increase the availability and the production rate of mining machineries. In this research, a historical failure dataset of a dragline has been utilized in order to analyze and conduct predictive maintenance. Authors have already utilized the K-Nearest Neighbors (KNN) algorithm in order to predict the failure mode; however, there was a chance of getting into local optimum by utilization of the mentioned methodology. In this case, combination of genetic algorithm and K-nearest neighbor algorithm (i.e., called enhanced K-nearest neighbors) was applied for the failure dataset, so the probability of local optimum has been decreased by application of genetic algorithm. In previous studies, the artificial neural network methods and conventional method of K-nearest neighbor have been applied to the same dataset, yet the result from enhanced K-nearest neighbor reveals better regression analysis.

A. Taghizadeh Vahed, B. Ghodrati, H. Hossienie

Effect of Spare Parts Policy on Equipment Production Loss in Mining

Spare parts inventory in a mine incorporates various mechanical to electrical equipment components that need to be available in case of any repair, preventive maintenance, and/or revision on equipment. These parts are generally stored at the mine sites under a specific policy in such a way that any equipment production delay due to unavailability of the spare part is mitigated or prevented. Scope of such a policy may consider i) frequencies of different failure modes, ii) their contributions to equipment downtime, iii) lead times and prices of spare parts, iv) administrative point of view, and v) risk appetite of the company. Since each part in an equipment holds changeable surviving and maintenance times with a random behavior, and lead times of spare parts variate according to their supplier service, it may be challenging to measure the effectiveness of an existing spare part policy and its effect on production loss. In this regard, this paper presents a simulation algorithm that is capable of measuring the negative addition of a spare part policy to the related mining production. A numeric example is also provided in the study for a quantitative verification.

O. Gölbaşı

Why Should Inspection Robots be used in Deep Underground Mines?

Deep underground mines impose new challenges for mining industry when searching for new hardly accessible deposits. These challenges are related to locations of deposits, their geometry, and harsh environment (dust, temperature, and humidity) including natural hazards (gas emission, water, and seismic events). Even nowadays, miners are allowed to work during shorter (6 h only) shifts. It is expected that this period will be shortened in the following years. More demanding conditions in the mine focus activities of companies and research institutions toward introducing robots to the mines. There are many successful examples of autonomous machines operated in the mine, robotized processes, and application of UAVs in open-cast mines. Unfortunately, applications of robotics in an underground mine are still limited. In this paper, we will introduce recently launched project THING, supported by H2020 EU programme that is devoted to the usage of autonomous quadrupedal robot ANYmal for inspection of infrastructure in deep copper ore mine. To be more precise, we will discuss how to support daily maintenance procedures for belt conveyors. In the paper, we will briefly present ANYmal, highlight main research tasks from maintenance and robotic perspective and discuss possible inspection missions for belt conveyor maintenance.

R. Zimroz, M. Hutter, M. Mistry, P. Stefaniak, K. Walas, J. Wodecki

Underground Track Design, Construction and Maintenance

In South Africa, rail haulage is the principal transportation method and will remain a significant factor in future underground mining operations. The mining engineer must be proficient in the use of railbound transportation systems in order that the lowest cost transportation system is selected and designed. Mine layouts and schedules must be efficiently planned and equipped combined with a culture to move personnel, material and rock safely, quickly and efficiently. This paper reviews rail haulages and provides mine planners and young mining engineers guidelines in the safe and efficient use of railbound haulage systems. The purpose of the paper is to provide a practical guideline for the design of trackbound underground transport systems for haulages. It is intended that the document be used by mine designers and planners as a reference guide during the design process. The paper looks at trackbound transport systems, track installation, mine cars and locomotive haulages. In addition, the paper evaluates such items as management, scheduling, haulage systems and general transportation safety issues.

S. M. Rupprecht

Research and Development to Improve Health and Safety in Mines


Sustainability Assessment of Angouran Lead and Zinc Mining Complex

Besides economic development, environmental and social impacts of mining on surrounding communities have been a major concern to governments, public, and stakeholders while the contributions of mining activities to economic development of Iran is well acknowledged, the gains from the mining sector to the economy is achieved at significant environmental, health, and social costs to the country. In order to investigate this subject, a sustainability assessment is done on Angouran lead and zinc mining complex as one of the largest open-pit mines in Iran and Middle Eastern countries. For this purpose, the environmental, social, and economic factors influencing sustainability of the project were identified through literature and field investigation, which were divided into 30 effective impacting factors. The study was based on 16 questionnaires. The results show that when comparing the main three aspects of sustainable development as economic, social, and environmental, the environment component has the most impact, whereas the social component has the least impact, as the least influencing component. Furthermore, among each individual aspect of sustainability, forest and ecosystem destruction, capital cost, final price, and employment are the most important with the obtained values of 1.063, 1.652, 1.706, and 1.511, respectively. Besides noise, NPV, and satisfaction of indigenous people have the lowest impact with the obtained values of 0.145, 0.635, and 0.818, respectively. With regards to results of the study, mine planners identify the undesirable impacts of mine activities on the region and are able to change their strategies in the mine and implement some remedial actions to reduce the destructive effects of mining on the region.

M. Heidari, M. Osanloo

Safety Towards Zero Harm in the South African Platinum Sector

South Africa is a mining powerhouse in Africa and it is the largest producer of platinum in the world. Historically, the overall safety performances of the mining sector were very high compared to the fatality rates of Australia, the USA and Canada. To address this, during the Mine Health and Safety Summit in 2003, the tripartite institutions, namely, Mine Health and Safety Council, various mining committees’ representatives and the Mining Qualification Authority (MQA) agreed that the South African safety statistics become comparable with their international counterparts. Working towards zero harm was the milestone that was agreed on and the period to reach this milestone was 2013. This required South Africa’s safety statistics to decline by 20% each year. This paper focuses on the South African platinum sector by comparing the overall safety performances of companies and identifies the potential sources of best practices in the platinum industry.

B. Genc, T. Mlangena, M. Onifade

A Move to a 12-Hour Working Shift—The Benefits and Concerns

As mining progresses deeper and further away from the shafts, the time to travel to and from the workplace increases. In South Africa, travelling times in excess of 3 h is becoming the norm rather than the exception. Travel times in shaft systems can equate to 45 min in each direction with a further 45 min required from the station to the working place. An addition to travelling a further 30 min is taken at the waiting place for the planning of the days work, safety discussions and the changing into the stope work clothes. Face time is further shortened by the re-entry examination in a stope, which can take up to 90–120 min depending upon ground conditions. The individual tasks required to complete the mining cycle: face preparation, support, drilling, charge/blast and cleaning remain a time-consuming process. Over the years, attempts have been made to speed up the mining process through innovation, new technologies, proper management and scheduling and there remains a deficiency in the available time on the working face to conduct all the activities required to achieve a safe, daily and quality blast. One of the proposed solutions to this problem is to introduce a change from a three-shift mining cycle (8 h 20 min) to a second 12-h working cycle. Mining personnel in countries, such as Australia and Canada, have been working on this type of cycle for many years. However, is this shift cycle suitable for South Africa mining conditions? Especially, as mining is often conducted in mature gold mines with working faces located far from the shafts. In the platinum mines, operations continue to progress deeper and also further from the shaft. Due to the depth of the South African gold mines and the high geothermal gradient associated with the Bushveld Complex (hosts the platinum deposits), environmental conditions may preclude long underground shifts. The paper investigates the opportunities available to increase the current working shift from 8-h 20-min shift to a 12-h shift. The article will highlight the advantages of moving to extended shifts while also identifying some of the difficulties that a 12-h shift holds for the workers.

S. M. Rupprecht

Mineral Processing


Optimizing the Rougher Flotation Process of Copper Ore

There are several mathematical models that search to optimize resources in different topics and areas. Chile being the largest copper producer in the world, where this natural resource is nonrenewable in the normal time frame, which means that over time these deposits will gradually have lower copper grades and then the cost of the process is increasing too. Our study begins with the challenge of finding the relevant parameters within this process and finally a mathematical model is proposed that optimizes the resources used, achieving greater recovery of the copper mineral, taking into account the inherent limitations of equipment, materials, conditions environmental, and others. The company seeks to maximize the law of copper concentrate and metallurgical recovery as an operation management strategy. Correlation is used to find the process variables that affect the grade copper and recovery. Some of the factors that are studied as input variables are the copper grade of the ore at the entrance of the flotation process, the amount of reagents and foaming agent used, and the granulometry, among others. To address this duplication of objectives, a linear regression approach is used subjected to restrictions associated with the permitted limits of each of the input variables. This model is validated with real data.

I. Derpich, V. Monardes

Modification of High Water Content Sediment for Rare Earth Mining in Deep Sea by Surfactants Agents

In recent years, the importance of rare mineral metal resources is increasing and a lot of investigations have been conducted all over the world in order to obtain new sources of rare metal resources. As a result, it was discovered that abundant rare-earth element-rich mud exists on the deep-sea floor in the Japanese Exclusive Economic Zone (EEZ). As one of the effective mining methods, a suction mining method is expected to be applied to the seabed mining. The seabed sediment containing rare-earth element shows the very high water content, more than 100% and the sediment movement during the suction is greatly affected by the water content and liquid limit of the material. In the laboratory testing, we investigate the relationship between the suction behavior of the sediment and these water content and liquid limit and found that the amount of suction of sediment and seabed deformation was described by these two parameters. Therefore, it is important to modify the liquid limit by adding chemical agent to control the sediment behavior. We selected eight different surfactants which can be divided into three types. They are dispersant type, water retention type, and thickener type. We carried out liquid limit test and viscosity measurement of the sediment mixed with the agents. It is found that the water-absorbing polymer increases the liquid limit and viscosity, whereas anionic/cationic surfactant decreases the liquid limit and viscosity. It is possible to control the sediment behavior by adding suitable surfactants.

T. Funatsu, T. Sakiyama, A. Hamanaka, T. Sasaoka, H. Shimada, K. Takahashi
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