The application of discrete event simulation for the optimization of the haulage methods of underground operations at great depth is presented. The discrete event simulation was carried out to evaluate four haulage methods for the improvement of the overall mine production and a minimizing of the operating costs. Other techniques can be applied to achieve the same objective but discrete event simulation is known for its advantage of more accurately accounting for real world uncertainty and diversity. Discrete event simulation is then combined with mixed integer programming to improve decision-making in the process of generating and optimizing the mine plans associated with each hauling option. The haulage system is one of the most important operations in underground mines as it involves the transportation of the mined out material from the draw points to the processing plant. When the depth increases, hauling of ore from deeper levels need to be evaluated in order to account for the constraints, configuration and current utilization of the ore handling system for improvement of productivity and operations. The increase in mine depth affects many factors among which are the increases in haulage distance from mine areas to the mine surface. The increase in haul distance results in an increase in the energy cost of the specific hauling equipment. The haulage process is one of the most energy-intensive activities in a mining operation and thus one of the main contributors to energy cost. This research uses the combination of discrete event simulation and mixed integer programing to compare the operating values of the mine plans generated for an orebody at depth levels of 1,000, 2,000, and 3,000 meters for diesel and electric trucks, shaft and belt conveyor haulage systems for the current and future energy prices.The results shows that, in comparison with analytical methods, discrete event simulation combined with Mixed Integer Programming (MIP) is faster and generates a more feasible solution, increases the understanding of the behavior of various systems, and reduces risk when selecting the operational systems. It is indicated that the energy cost increases as the mine depth increases and it differs for each haulage method for both current and future energy prices with higher costs in diesel trucks and lowest costs when using a shaft haulage system. The energy costs for diesel trucks account for 38.2%, 46.8% and 63.1% of operating costs at the current energy price, and 64.9%, 72.5% and 83.7% of operating costs at the future energy prices at the 1,000, 2,000 and 3,000 meter depth levels respectively, while the energy cost for the shaft haulage system accounts for 10.8%, 13.0% and 15.4% of operating costs at the current energy price, and for 26.6%, 30.9% and 35.4% of operating costs at the future energy price at the 1,000, 2,000 and 3,000 meter depth levels respectively. The energy costs is further analyzed based on haulage costs as a percentage of the total operating cost for all options, and the results show that diesel truck haulage is substantially more expensive compared to other haulage options with least energy cost on shaft haulage system with increasing depth. This study thus provides mining companies operating at great depths, a broad and up-to-date analysis of the impact on energy costs on the haulage methods as the mine depth increases.

The Luossavaara-Kiirunavaara Aktiebolag (LKAB) Kiirunavaara mine is a large scale sub-level caving (SLC) mine in northern Sweden. The use of SLC as a mining method inherently causes significant rock mass movements above the extraction level. It has been one of the objectives of LKAB since the early 1990s to accurately forecast the global stability of the footwall in relation to the inherent rock mass movements from the sub-level caving. In the Kiirunavaara case, the dip of the main ore-body entails the footwall to develop as a rockslope confined by cave material from the hangingwall. It has been discussed that the global stability of the footwall is likely related to the interaction of two or more failure mechanisms acting in combination, however, the true footwall failuremechanisms are still debated. The objective of this thesis is to study and evaluate the footwall behaviour and determine the predominant mechanisms by combining data from field observations, numerical modelling and seismic data analysis. Field data was collected through damage mapping on decommissioned levels in the footwall on depths between 120 to 700 m for the full 4 km ore-body length. From the mapping data a conceptual boundary between damaged and undamaged footwall rock was established in the form of a damage boundary surface. The 3D geometry of the damage surface was analysed and a section was extracted and used in calibrating numerical models for simulatingthe footwall behaviour in response to mining. A parametric study was performed to highlight high impact inputs and study plausible origins of the conceptual damage surface. A base case model was adopted to explain the failure evolution and used in the analysis of seismic data. The seismic data was analysed with respect to origin mechanisms as well as temporal and spatial location patterns. The outline of the large scale footwall fracturing interpreted from the conceptual damage surface was geometrically complex. No single principal failure modes could be identified from evaluating the 3D geometry favouring the initial assumption of multiple mechanism interactions. In addition, the mapping data itself indicated changes in failure mode with respect to depth. On higher levels structurally controlled damages were predominant while general rock mass failures became common on lower levels. The parametric study related thehighest influence on plastic response to the internal cohesion followed by internal friction angle. This was interpreted for the base case as the rock mass being more sensitive to shear failures in favour of tensile failures. This indication was further strengthened by the evaluation of the seismic data. The origin analysis of the seismic events pointed to a significant dominance of shear origin events clustered in active fracturing volume indicated by the base case numerical analysis. By combining field observations, numerical modelling and seismic analysis a plausible description of the large scale footwall fracturing could be provided. The structurally controlled failures in the upper and mid portion of the footwall are reactions to active failure on deeper lying levels. Active fracturing of the footwall rock mass occurs based on the numerical and seismic results on levels on and underneath the current mining level. On the levels where active fracturing takes place the rock mass is confined by the support pressurefrom the un-mined ore-body. As mining progresses deeper the confinement is lowered as the ore is replaced by low stiffness cave rock. Due to the loss of support pressure the rock mass expands towards the sub-level cave and the induced weaknesses are activated and manifested as drift damage during rock mass mobilisation. The numerical models showed that the mobilised rock mass above the mining level exhibits the displacement pattern of a potential curved shear failure. This failure path intersects both the footwall slope face and thestructures from the upper footwall and thus enables these structures to shear.

The expansion of economic activities and increasing mobility of people on short, medium and long distance trips is an issue that requires attention in the transport industry. The need to address this demanding issue in a sustainable and economically efficient way is the core of general capacity challenge in railway industries. This informs the strategic objective of ensuring an efficient and competitive mode of transportation by many infrastructure managers including Swedish Transport Administration. An aspect of railway infrastructure management which is promising for the enhancement of existing infrastructure capacity is the improvement of maintenance process. The frequency of traffic interruption due to infrastructure failure, reduction of functional performance due to infrastructure degradation and length of track possession time are incidences limiting operational availability of railway infrastructure and capacity thereof. Achieving the goal of supporting the inherent capacity of existing railway infrastructure requires implementation of effective & efficient practices for large and small impact maintenance tasks. This research has addressed the above mentioned concerns by studying the opportunities which maintenance presents towards enhancing the capacity of existing railway infrastructure. Outsourcing aspect of maintenance organisation has been studied and a conceptual framework to facilitate the implementation of performance based maintenance contracting is proposed. This will enable the achievement of quantity and quality requirements of traffic performance. Furthermore a risk assessment procedure has been presented to identify bottlenecks restricting the capacity on any line and also for continuous improvement has been suggested. A model for planning and scheduling of tamping action has been presented. This will lead to reduced track possession time and minimum cost of intervention while geometry quality is kept at desirable level. Case studies on the above procedures and model have been presented to demonstrate their application for maintenance improvement.The outcome of this study is development of effective maintenance principles that should serve as basis for maintenance improvement programme to support reliable and inherent capacity of existing railway network. This improvement covers organisational and technical performance, all enhancing the possibility to increase the capacity of railway network.

The railway is an important mode of transport, due to its environmental friendliness, high safety level, and low energy consumption, among other reasons. Railways provide a sustainable means of transporting a large amount of freight and passengers, in a cost-effective and comfortable way. The railway system has a large number of stakeholders and a small improvement in the system will give many advantages, including financial savings and an increase in the quality of service. The Swedish railway network is old and there has been almost no expansion of the network during the past few decades. There is currently a demand for more track capacity and there are no more tracks availably at the network; therefore, the existing network is expected to deliver more capacity.The railway operators are the largest cause of train delays and wheel failures are one major contributor of the delays caused by operators. The infrastructure manager is the second largest owner of train delays, and a large contributor of their train delays is switches and crossings (S&Cs). This thesis shows proposals for how condition monitoring technology can be used more efficiently for both the infrastructure and the rolling stock to increase the reliability of their critical items by decreasing train delay. Firstly, the condition of the wheel-rail interface is important, in that a bad wheel influences the rail and vice versa. The monitoring of rail profiles is already in use, but the monitoring of wheel profiles is still in the development phase. This thesis shows the performance of a wheel profile measurement system (WPMS) for an extreme climate, and a case study of performance measures such as the accuracy and reliability of the system is presented. An additional topic dealt with is how the information from the WPMS can be combined with that from the wheel defect detectors to find early indications of wheels with bad behaviour. Secondly, the S&C is an essential component of a railway system in that it increases the flexibility by diverting traffic, but S&Cs need adequate support to work properly. A camera-monitoring method for S&Cs is presented which increases the inspection frequency and decreases the human activities on the track and the train delay. In conclusion, this thesis shows that the WPMS investigated works well with a high level of performance concerning measurement accuracy and reliability in an extreme climate, and that there is still some potential for improving the system. The combination of the WPMS and wheel defect detectors shows that wheels with a high flange height have a higher probability of ending up as wheels suffering from failures. A new maintenance limit for the flange height can reduce the number of wheel defects on the track. Camera-monitoring of the S&C will increase the availability and reliability of this item and even reduce the time on the track required for the maintenance action “check” through fewer inspections and maintenance actions. These proposed monitoring techniques can improve the railway system reliability by reducing the consequential train delay times, by decreasing the number of failures of wheels and S&Cs.

Railway traffic has increased over the last decade and it is believed to increase further with transportation shifting from road to rail, due to rising energy costs and the demand to reduce emissions. To manage railway infrastructure assets effectively against agreed-upon and set objectives, performance must be measured and monitored. Different systems are used to collect and store data of traffic, failures, inspections, track quality, etc., for subsequent analysis and data exchange. Performance indicators (PIs), e.g. for RAMS (reliability, availability, maintainability, safety), are continuously developed to support infrastructure managers (IMs) in identifying performance killers in order to make efficient and effective decisions. However, they are often ad hoc and seldom standardised. Moreover, the use of standards and the need for harmonisation of railway operations have grown with interoperability, e.g. building of a trans-European railway network. The~efficiency and effectiveness of railway infrastructure can be improved if an appropriate performance measurement (PM) system is identified and specifically developed. In traditional PM systems, PIs are given threshold values, indicating when an action needs to be taken, i.e. they can to some extent be reactive. Also, PIs are often aggregated measures, which can make them abstract. By this trend in transportation and shortcomings in performance measurement, there is a need to improve the strategic planning and measurement of performance for more proactive decision making and future standardisation.In this research, a link and effect model for performance improvement of railway infrastructure is developed. It provides a continuous methodology for breaking down objectives into operational requirements and linking them to results, using performance indicators, and algorithms for data analysis and simulation, for decision support.Keywords: railway infrastructure, performance, RAMS, maintenance, dependability, indicators, link and effect, decision support / Link and Effect Model for Maintenance of Railway Infrastructure

The interaction of the geological and mining environments leads to a variety of forms of rock mass behaviour, including seismicity and falls of ground. A precise understanding, however, of the role of geology in rock mass behaviour experienced by Luossavaara-Kiirunavaara Aktiebolag’s (LKAB) Kiirunavaara Mine remains unknown.Since late 2008, the sublevel caving mine regularly experiences induced seismicity (Dahnér et al., 2012). Seismic events occur in the footwall, orebody, and hangingwall. Instabilities, sometimes related to specific seismic events, are unevenly distributed throughout the rock mass. Failure mechanisms of these instabilities include structurally controlled failure (sometimes as shake down), strainbursting and spalling, which are typically a result of local stress changes. Occasionally, these falls of ground are rockbursts; violent ejections of rock causing damage to infrastructure and/or personnel that are caused by remote seismic events.Some previous work has been done at the Kiirunavaara Mine for both specific events and specific volumes to better understand the rock mass behaviour (see e.g., Sjöberg et al., 2011, 2012). However, the causes of the uneven distribution of both seismicity and instabilities at the mine are not understood, particularly at the mine-scale. As part of a larger Ph.D. project, this study explores the role of geology in the mine-scale behaviour at the Kiirunavaara Mine. This is done through two approaches: 1) exploratory numerical stress modelling, and 2) development of a geomechanical model of the rock mass.The exploratory numerical modelling of the mine evaluated common assumptions made by researchers and consultants when completing numerical stress modelling of this orebody. A previously estimated virgin in situ stress state was applied in a 3-D model developed of the nearly 5 km long orebody and surrounding host rock. The model had definition between footwall, ore and hangingwall materials. Run as a continuum for this analysis, the stresses from the elastic and perfectly plastic models corresponded to stresses recently measured in situ at two sites using overcoring, indicating that the estimated virgin stress state is consistent at depth. Alternating two commonly used perfectly plastic material properties for the footwall significantly influenced the location of plastic failure throughout the rock mass, including in the hangingwall. A physical alignment of plastic failure from the models and mine seismicity for the entire rock mass was not found for the individual cases. Large magnitude shear events tended to be external to plastic failure. The difficulties relating plastic failure to seismicity can be associated with a number of causes, including that the rock mass characteristics were too simplified (for example, no discontinuities were included, the only geological units included were the footwall, hangingwall and orebody, etc.) to represent the rock mass behaviour.A geomechanical model of the rock mass is needed to better understand characteristics of the rock mass, in addition to those included in the stress models, which may be of importance to behaviour. Due to a complex, heterogeneous and clay-altered rock mass, a new methodology was developed to create a geomechanical model. The methodology is based upon standard statistics, geostatistics, and an extension of previous quantitative domaining work. Clay volumes (represented by a model based on borehole data calibrated to underground mapping) correlated to the geomechanical characteristics and behaviour of the rock mass. The rock mass in the immediate vicinity of the volumes of clay alteration had lower RQD values, more random jointing, and a higher concentration of falls of ground than the surrounding rock mass. The correlation between the geomechanical model and the falls of ground lead to the development of a new conceptual model of some of the mine-scale rock mass behaviour, in which the clay volumes play a significant role in stress redistribution.The understanding developed through this study has laid the framework for future analysis of a more advanced and complex nature. Numerical stress analysis will be used to test the conceptual model developed and further analyze the relationship between geology and mining, with the intention of improving the understanding of the causes of rock mass behaviour. This improved understanding has the potential to aid with selection of production planning alternatives for risk mitigation, not only for the Kiirunavaara Mine, but for other highly stressed, hard rock environments.

Railway infrastructure is a complex system which comprises different subsystems. Long useful life span is one of the important aspects of this prime mode of transport. The useful life length of its assets is highly dependent on the maintenance and renewal strategy used during its life cycle. Today’s demands on the railway industry call for increased capacity, including more trains, travelling at higher speeds with higher axle loads. This increased usage will result in higher degradation of railway asset and higher maintenance costs. However, due to the competitive environment and limited budgets, railway infrastructure managers are compelled to optimize operation and maintenance procedures to decrease operation and maintenance costs while meeting high safety standards. To assure track safety and maintain high quality, a cost effective track maintenance strategy is required, one based not only on technical and/or safety limits but also on cost-effective maintenance thresholds. RAMS (Reliability, Availability, Maintainability and Safety) and LCC (Life Cycle Cost) analyses, which are derived from reliable track condition data, provide an approach to specify cost effective maintenance strategy to lessen corrective maintenance actions and downtimes.One of the main parameters to assure railway safety and comfortable railway service is to maintain high quality of track geometry. Poor track geometry quality, directly or indirectly, may result in safety problems, speed reduction, traffic disruption, greater maintenance cost and higher degradation rate of the other railway components (e.g. rails, wheels, switch, crossings etc.). The aim of this study is to develop a methodology to optimize track geometry maintenance by using historical geometry data. The methodology is based on reliability and cost analysis and supports the maintenance decision-making process to identify cost-effective inspection interval. An important phase of track geometry maintenance optimization is to estimate the track degradation rate. Obtaining knowledge about degradation helps to properly schedule maintenance activities such as inspection and tamping.The thesis provides a methodology to identify a cost-effective inspection interval based on track degradation rate and cost drivers. It contains state-of-the-art track geometry maintenance optimization. It describes Trafikverket’s (Swedish Transport Administration) maintenance strategy regarding measurements, reporting on and improving track quality, and it evaluates the efficiency of this strategy. Finally, it includes a case study carried out on the iron ore line in north of Sweden that runs from Boden to Gällivare to evaluate track geometry degradation and analyze the probability distributions of failures. A cost model is developed in order to find optimal inspection interval.Keywords: Track geometry degradation, Track maintenance optimization, Maintenance planning, Tamping

Railway signalling systems are composed of several different systems; each has its own purpose, but the main functionality of the overall system is determined by the interoperability between them. Railway signalling systems ensure the safe operation of the railway network, and their reliability and maintainability directly affect the capacity and availability of the railway network, in terms of both infrastructure and trains. The functionality of the signalling system is based on the principle of “fail safe”; this means that the railway section where a failure is located will be not fully operative until the failure is repaired (since safety cannot be ensured). Hence, the dependability of these systems directly affects the capacity of the network.Signalling systems take up a large part of the railway’s overall corrective maintenance. Railway managers need to have a holistic view of all systems to optimise maintenance. Signalling systems are especially important, given the need for interoperability. Given their complexity, knowledge must be correctly managed to ensure proper performance in all phases of the life cycle. Enhancing information logistics would lead to considerable improvements in this area. This licentiate analyses the dependability and maintenance of railway signalling systems and proposes various approaches to improve maintenance performance. External factors affecting the reliability of signalling systems are identified, such as their location. The signalling system is treated as a system of systems because of its interoperability and because failures occurring on different systems can be associated with the same failure effect. A data driven model for maintenance decision support is proposed, based on corrective maintenance work orders. The data driven model allows a holistic perspective of failure occurrence, as it integrates the information recorded in the many different parameters of the corrective maintenance work orders. With this model, existing maintenance policies could be reviewed and improved upon. This thesis proposes a model for configuration management, which simplifies the access and visibility of information. The model manages the change control process and ensures that configurations are updated in real-time. An enhancement of the configuration management has the potential to increase the efficacy of the maintenance actions in signalling systems by improving the accessibility of the information required to understand possible future failures. With increased accessible knowledge, the time needed to identify failures can be reduced, resulting in greater maintenance efficiency. It also establishes a framework for improving inter-organisational knowledge management between stakeholders, resulting in the creation of a holistic perspective of the maintenance and operation of the railway network, avoiding the loss of knowledge linked to outsourcing, and improving the effectiveness of the organisations involved.

Load Haul Dump (LHD) machines are used in underground mines to load and transport ore and minerals. Loading and hauling blasted ore from drawpoint to dumping point constitute a significant portion of the production costs for mining companies. There are a number of operation modes available for LHDs, and there are many criteria to consider when selecting the best one. The use of automated LHDs has been widely discussed due to the potential to increase productivity. The increasing focus on safety and ergonomics also gives an edge to automatically operated loaders over manually operated ones. Mine managers must decide when it is preferable to use manually operated loaders and when to complement or replace these with automatic ones. Automation focus has over the years gradually shifted from having automated fleets of vehicles to the more flexible solutions with semi-automatic LHDs gaining safety as one of the main goals. Several issues must be resolved to maximize the benefits of automation. One is to improve maintenance, and moving from operatorassisted “fail and fix” to planned maintenance. Since the operator is removed from the machine during automatic operation and maintenance staff is not always available on short notice, it is crucial to increase planned maintenance to maximize the investment in automation. Another issue is the complexity of the mining environment, including both the infrastructure and external disturbances like oversized boulders and road maintenance, as these can throw the entire investment in automation into question. The purpose of this thesis is to explore the maintenance actions connected to automated LHDs as well as the factors influencing the dependability of the machine. Research methods include a literature review, interviews, and data collection and analysis. Real time process data, operation and maintenance data have been refined, integrated and aggregated to make a comparative analysis of manual and automatic LHDs. The analysis show that 75% of the stop occasions causing idle time for LHDs relate to the operating environment, 21.5% pertain to machine related issues and 3.5% are related to the infrastructure of the automatic system installed in the mine. There is no difference in what kind of maintenance actions that are taken for manually and automatically operated LHDs, but there is a difference in what type of failures that occurs more frequently for the different operation modes. For automation of LHDs too much unplanned repairs and maintenance work significantly reduces the overall availability and can jeopardize the entire investment in automation. The difference between the semi-automatic and the manual LHD was found to be very small in terms of maintenance cost versus produced number of tons. However, a semi-automated LHD is an optimal machine regarding the ability to adapt to reconfiguring the operation mode to meet demands such as safety, flexibility and productivity.

Drill and blast is a dominant technique in several surface and underground mines in the world. The purpose of this technique is to break rock mass into fragments, which can be handled by mining equipment. The identified major influencing factors in rock blasting are stress waves and gas pressurization. In underground mines, especially in sublevel caving mines, the blast is performed under confined conditions. Hence, one more category of mechanisms has to be taken into consideration which describes the behavior of granular materials. Several small-scale tests have been conducted in order to define parameters which affect fragmentation by blasting as well as to measure the burden behavior during blasting. The purpose of these tests was to investigate how firing pattern, confinement and inter-hole delay time influence the fragmentation. Additionally, an incremental relative distance sensor was developed to measure the burden movement during blasting. The results showed that the burden moved with a velocity of approximately 29 m/s. The V-shaped firing pattern gave coarser fragmentation compared with sequential firing pattern for both the blasted material and confining material.After the small-scale tests, a zero pillar test was conducted under confined conditions to evaluate and validate a newly developed measuring system. The purpose of this system was to measure the burden dynamics. The system was calibrated in laboratory conditions under dynamic loading. This system was based on a piston-like structure and it was equipped with accelerometers and a potentiometric distance sensor. In addition to the measuring system, several installation and initiation procedures have been developed. The results of the measuring system showed that the burden moved 0.98 m at a velocity of 17-18 m/s. All the procedures performed as well as expected and designed.In addition to the study of blasting related mechanisms, the results of a blast also have to be measured. Sieving is usually not an option for large scale operations due to high costs. The alternative way is to implement digital image analysis. This procedure does not interfere with the production of a mine. Several trials have been conducted at the Aitik open pit mine to investigate the influence of short inter-hole delay time (1 ms, 3 ms and 6 ms or 0.14 ms/m burden, 0.43 ms/m burden and 0.86 ms/m burden) on fragmentation. The examined mechanism was the interaction of stress waves between neighboring blastholes. The fragmentation results showed that the trial with 3 ms inter-hole delay time gave a finer fragmentation by 10 % compared with reference blasts and other trials. However, there was an indication that the large specific charge at the mine overshadows the stress wave interaction mechanisms.An additional set of trials was conducted at the Kiruna mine to investigate the gravity flow of broken material. The fragmentation measurements were done with SplitDesktop®. This is a digital image analysis software which calculates fragmentation based on a delineation process of the particles in an image. The aim of in these trials was to develop a procedure to minimize the image editing time. The application of ‘Unsharp Mask’ filter improved the image quality and enhanced the contrast between the particles combined with a quick rating system (developed by LKAB) so that the image processing time was significantly reduced from 2 hours to 10-15 minutes.