Sublevel caving is a highly mechanizable mass mining method normally utilized in large, steeply dipping orebodies. The fragmented ore flows freely, aided by gravity, down to the drawpoint while the surrounding waste rock caves in due to induced stresses and gravity. Fragmentation of the blasted ore is a vital component in any mining operation and directly affects productivity and efficiency of the following production steps (Nielsen et. al, 1996). In an attempt to reduce mining induced seismicity in Malmberget, LKAB is initiating various trials. One of these trials involves a reduction in blasthole dimension and an increase in the number of blastholes utilized in each ring. A reduction in blasthole dimension is undertaken to achieve a less impactful mining operation in terms of disturbances to surface populated areas, particularly addressed to ground vibrations. Therefore, it is of utmost importance to analyse if fragmentation and production is affected as a consequence of this change. This thesis sets out to evaluate how fragmentation and the LHD operation is affected by variations in blasthole dimension. The evaluation is carried out through analysis of logged production data, on-site filming of the loading sequence and interviews with the LHD operators. The discoveries will be presented chronologically to illustrate the complexities related to compiling a viable dataset to rely on for a credible analysis. The initial theory did not hold up properly and therefore the project was reshaped along the course of progression to provide further information and clarify uncertainties. Unfortunate, major production delays inhibited a quantitative comparison of two parallel drifts with different blasthole dimensions. Hence, no final answer can be provided in this thesis whether a change in blasthole dimension causes any differences in loadability and/or fragmentation or not. However, an analysis of how cycle times vary depending on causes such as operator induced differences, machine induced differences and road conditions will be provided. The field test also provides information on various loading scenarios and the difficulties connected to these. The result obtained in this project mainly addresses the significant operator difference in terms of cycle times which can extend to, on average, 60% depending on experience, road conditions and, most likely, preferences amongst operators. Time differences amongst seemingly experienced operators can reach more than, on average, 30% in hauling time alone. Roughly 96% of the operators state that road conditions in the production area is the controlling factor for hauling speed. Many of the operators further states that the risk of injuries is directly related to road conditions and this is a likely cause to why cycle times vary in this magnitude. Fragmentation was found to affect loadability but not to the same extent as shape and looseness of the muck pile. Compaction of the muck pile and flow disturbances where normally found to be connected to one another. Hence, good loadability would indicate a low occurrence of flow disturbances and a continuous flow of material into the drawpoint. This thesis is written as a part of the final stage of the civil engineering program at Luleå University of Technology (LTU) and represents 30 credits in the field of Soil and Rock Construction. The thesis is a part of a larger project, Face to surface, which sets out to analyse the impact of fragmentation on different stages in the production chain.

As an important sector of the global economy, underground mining serves as the foundation for the economies of many nations. It involves the extraction of precious minerals, ores, and other geological elements. Mining requires the use of specialised machinery and equipment, such as the Load-Haul-Dump (LHD) machines, which carries out the loading, hauling and dumping of the fragmented ores. Despite the widespread use of LHDs, there still exists a knowledge gap regarding research that considers the effects of several operational, technical, and environmental factors of the LHD general performance. This master thesis focuses on analysing the Load-Haul-Dump (LHD) machine operations and it aims to provide a comprehensive understanding of the different components of an ideal LHD operation: machine performance, machine and bucket design, bucket filling and loading operation, condition of the material to be loaded, machine care, and other mining related issues, and their connections via a throughout literature review. A traditional literature review served as the foundation for the development of this thesis. This kind of review is based on recent and current investigations accesible. In order to describe the main factors affecting an LHD operation, the literature research approach included reading, assessing, and categorising the literature regarding each individual factor. The findings of this research were compiled in the form of key findings presented on a bullet point list format. The findings serve as recommendations on how the different factors analysed help with either the improvement of the LHD operation or may negatively affect the performance of said LHDs.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / The current study is based on a multiple linear regression analysis with an objective to formulate an equation related to the productivity analysis of LHD equipment using independent variables such as the effective utilization of the equipment. To identify the independent variables, main productive factors, such as the actual capacity of the buckets, the transport cycles in the cleaning process, and the performance by means of curves, were analyzed. Comparisons of a Peruvian underground mine case study exhibited that the battery-powered equipment denoted similar production efficiencies to that exhibited by its diesel counterparts; however, the three-tier approach observed that the battery-powered equipment could achieve production efficiencies that are up to 13.8% more as compared to that achieved using its diesel counterparts because of increased effective utilization that can be attributed to long MTBF. The results of this study exhibit that LHDs under battery-powered storage are feasible for underground mining not only because of the fact that they do not emit any polluting gases, which helps to mitigate pollution, but also because of their good production performance that can be considered to be an important pillar in deep mining. Copyright 2019.

La presente investigación se titula “Propuesta de uso de equipo LHD a batería como alternativa competitiva frente al equipo diésel en el proceso de limpieza de labores subterráneas horizontales en una operación minera mecanizada”. Este estudio tiene como objetivo evaluar una propuesta de uso del equipo LHD a batería como alternativa competitiva frente al equipo diésel en el proceso de limpieza de labores subterráneas horizontales determinando los factores productivos, analizando la sostenibilidad ambiental y evaluando los costos operacionales relacionada a los equipos LHD diésel y batería. Asimismo, para la evaluación comparativa de estos equipos se realizó un análisis a través de un caso de estudio en una unidad minera de operación mecanizada, con similares características a la Unidad Minera Atacocha. Los equipos que serán utilizados para la evaluación, bajo las mismas condiciones de trabajo, son el LHD a batería (ST7), de la empresa Epiroc, y el LHD diésel (R 1300G), de la empresa Caterpillar; ambos con una capacidad de carga útil nominal de 6,800 kg (4.2 yd3). Los resultados obtenidos a través del caso de estudio se dieron en tres niveles: productivo, sostenible ambiental y económico. En el aspecto productivo, se determinó que el equipo LHD a batería en comparación con el equipo LHD a diésel, para una distancia de acarreo de 150 m, tiene un menor tiempo de ciclo de 8.23%, y un mayor rendimiento productivo de 8.98%. En relación a los indicadores de gestión, se determinó que los equipos LHD a batería posee una ventaja frente a los equipos diésel como en los indicadores de disponibilidad mecánica, utilización efectiva, MTBF y MTTR, obteniendo que en los tres primeros es mayor en 0.51%, 10.45%, 4.8%, respectivamente; por el lado del indicador de MTTR, con un resultado de 12.52% menor que el equipo diésel. En el aspecto de sostenibilidad ambiental, cuando se tiene al equipo diésel en funcionamiento se incrementan los niveles de gases en comparación a los equipos a batería en 76.63% en CO, 72.45% en CO2, 50% en NO2; asimismo, en la zona de trabajo del equipo diésel, se genera un incremento de temperatura de 19°C mientras que con el equipo a batería se tiene un incremento de 3.5°C. Finalmente, en el aspecto económico, se determinó que los equipos a diésel poseen un menor costo de posesión de 35.28 $/hr, un mayor costo operacional de 31.24 $/hr y un mayor costo total, incluyendo costo ventilación, de 1.63 $/hr a diferencia del equipo a batería. / This research is titled "Proposal for the use of battery-powered LHD equipment as a competitive alternative to diesel equipment in the cleaning process of horizontal underground workings in a mechanized mining operation." This study aims to evaluate a proposal for the use of battery-powered LHD equipment as a competitive alternative to diesel equipment in the cleaning process of horizontal underground workings, determining the productive factors, analyzing environmental sustainability and evaluating the operational costs related to LHD equipment. diesel and battery. Likewise, for the comparative evaluation of these equipment, an analysis was carried out through a case study in a mechanized mining unit, with similar characteristics to the Atacocha Mining Unit. The equipment that will be used for the evaluation, under the same working conditions, are the battery-powered LHD (ST7), from Epiroc, and the diesel LHD (R 1300G), from Caterpillar; both with a rated payload capacity of 6,800 kg (4.2 yd3). The results obtained through the case study occurred at three levels: productive, environmentally sustainable and economic. In the productive aspect, it was determined that the battery-powered LHD equipment compared to the diesel-powered LHD equipment, for a hauling distance of 150 m, has a shorter cycle time of 8.23%, and a higher productive performance of 8.98%. In relation to the management indicators, it was determined that battery-powered LHD equipment has an advantage over diesel equipment as in the indicators of mechanical availability, effective use, MTBF and MTTR, obtaining that in the first three it is greater by 0.51% , 10.45%, 4.8%, respectively; on the side of the MTTR indicator, with a result of 12.52% lower than the diesel equipment. In the aspect of environmental sustainability, when the diesel equipment is in operation, the levels of gases are increased compared to battery-powered equipment by 76.63% in CO, 72.45% in CO2, 50% in NO2; Likewise, in the work area of the diesel equipment, a temperature increase of 19 °C is generated, while with the battery-powered equipment there is an increase of 3.5 °C. Finally, in the economic aspect, it was determined that diesel equipment has a lower cost of ownership of 35.28 $/hr, a higher operating cost of 31.24 $ /hr and a higher total cost, including ventilation cost, of 1.63 $/hr unlike battery powered equipment. / Tesis

Ingeniero Civil Eléctrico / La robótica y automatización han tenido un gran impacto en la industria en el país, aumentando sustancialmente la productividad de ésta a lo largo de los años. Uno de los procesos que se ha buscado automatizar en minería, es la extracción de mineral en minas subterráneas, el que se realiza por un Load Haul Dump. Este proceso ha sido parcialmente automatizado, quedando pendiente desarrollar de manera efectiva proceso de carguío para que sea autónomo. Este es difícil de automatizar debido a la variabilidad de la granulometría del material a cargar que se encuentra en el punto te extracción. Esta memoria se enmarcó en el proyecto de automatización del proceso de carga de un LHD en el Advanced Mining Technology Center (AMTC) de la Universidad de Chile. El trabajo consistió en el diseño y desarrollo de un sistema de medición granulometría del mineral en un punto de extracción y la entrega de un punto en donde se recomiende iniciar la carga de este. En este trabajo se diseña y desarrolla una maqueta a escala del punto de extracción real, en la que utilizando un láser actuado por medio de un servo motor y el framework ROS, se obtiene una nube de puntos la que es procesada por un algoritmo que ocupa segmentación en tres dimensiones. De esta manera se obtiene una serie de clústeres representando cada una de las rocas. Además se implementa un filtro de manera que rocas detectadas con un volumen menor al impuesto por el usuario, no serán consideradas, y finalmente utilizando esta información se entrega una línea en la que se recomienda comenzar el carguío. Este sistema fue sujeto a una serie de pruebas con distintas rocas en diferentes configuraciones obteniendo un error promedio de 14,17 %. También fue sujeto a prueba en un ambiente húmedo, en el que el rendimiento se mantuvo constante y a pruebas en un ambiente con polvo, en donde el láser no fue capaz de atravesarlo por lo que no se obtuvieron resultados. Finalmente se encontró que el tiempo en el que se entrega una nube de puntos por el sistema es 12 segundos y se realizó un análisis teórico para concluir que estos resultados son representativos en un ambiente real. Concluyendo, se desarrolló un sistema capaz de diferenciar las rocas relevantes del fino, obteniendo su granulometría utilizando el framework ROS y el hardware requerido. El trabajo realizado abre las puertas para el desarrollo y prueba de nuevas estrategias de carguío autónomo en el AMTC. Como trabajo futuro se propone caracterizar rigurosamente el desempeño del láser en ambientes con polvo y realizar pruebas con un LHD a escala para determinar la efectividad de la estrategia de carguío entregada en este trabajo, además de una serie de sugerencias para mejorar el desempeño del algoritmo desarrollado.

The magnetically confined plasmas study is one of the most promising research fields in the present days due to the high perspectives of unlimited and clean energy that fusion has generated. In this framework, the stellarator devices play a significant role because of, unlike in the tokamak case, their continuum working regime, which will be an essential feature of the future fusion commercial reactor.Heat transport studies in stellarator devices are completely necessary since the main plasma properties (and therefore, the total fusion power generated) are absolutely dependent. Nowadays, the largest stellarator in the world is the Large Helical Device (LHD). There is also a stellarator device is Spain, TJ-II, which is located in the installations of CIEMAT in Madrid. In this thesis, turbulent and conductive heat transport is studied in both devices with the aim of comparing its formation and suppression. First of all, collisional transport, i.e. neoclassical transport, which is caused by the particle collisions, is studied by means of a new transport model implemented in the transport code PRETOR-Stellarator. This model is able to calculate heat diffusivities as well as the neoclassical electric field with reasonable accuracy without spending as much computational time as in the Monte Carlo techniques. It is deduced from the results that, for both TJ-II and LHD, neoclassical transport may be quite important in plasmas with low density and high temperatures, although higher levels of neoclassical transport are obtained in TJ-II. Both devices share the feature that in low collisional plasmas, a high positive neoclassical electric field with a high shear appears in the plasma core. This electric field can be responsible of the suppression of the turbulence heat transport.Some new turbulent heat transport models have been added to PRETOR-Stellarator in order to study this kind of transport. Both, LHD and TJ-II, share a common heat transport in the confinement region (plasma core), called drift wave electromagnetic transport, and which is due to the fluctuations of the magnetic field. Outside this region, turbulent heat transport in LHD has similar characteristic to that in tokamaks, whereas in TJ-II, turbulent transport is maintained.Turbulent heat transport reduction is a major issue in fusion research, since the capability of producing commercial fusion energy depends strongly on the low levels of turbulence of the plasma. The appearance of a neoclassical electric field in the plasma core and its interaction with turbulent transport has been studied. It is shown that this electric field is able to generate a rotation in the plasma which is able to suppress turbulent transport to neoclassical levels when density is low enough. These plasmas are called to have an internal transport barrier and have stepped electron temperature profiles with hollow electron density profiles. Another important phenomenon related with electron heat transport is non-local transport, which can not be studied within the general diffusive framework that is used to study turbulent transport in plasmas. The non-local transport is caused by the interaction of long distant parts of the plasma. In this thesis, a new model for this type of transport, which is based on the convolution over a kernel of the neoclassical transport, has been proposed to explain this phenomenon. It has been shown that this model is able to simulate the main characteristics of this transport, e.g. fast pulses propagation, ballistic transport or the growing of the turbulence levels close to the axis of the device. All these phenomena have been observed in LHD and TJ-II. Finally, once electron heat transport in stellarators has been clarified, a comparison of the designs of the future commercial reactor based on both, stellarators and tokamaks, has been carried out. A stellarator commercial reactor, based on the design of the LHD, would have a 15.5 m major radius, 2.5 m minor radius, with a continuum working regime based on low temperatures and high densities. Main energy sinks are due to conductive-convective heat losses and radiation losses (in a 95% from Bremmstrahlung radiation). The fact that it has such a large major radius makes this design expensive and difficult to build. A tokamak fusion reactor would be smaller, however, the high temperatures achieved make cyclotron radiation losses to be very high, and a wall with a high reflection coefficient seems to be necessary. / L'estudi de les propietats dels plasmes confinats magnèticament esta esdevenint un dels temes primordials de recerca degut a les prometedores perspectives (de netedat i ampli abast) que l'energia produïda per fusió nuclear està fomentant. Es dins d'aquest context on l'estudi dels dispositius de confinament magnètic de tipus stellarator juguen un paper molt important, ja que un reactor de fusió basat en aquest concepte podria tenir (al contrari dels tokamaks) un mode de funcionament continu i no polsat.L'estudi del transport de calor en el dispositius de fusió per confinament magnètic de tipus stellarator és totalment necessari, ja que les propietats del plasma (i per tant de l'energia produïda per fusió) en depenen completament. Actualment, el stellarator més gran del món es troba al Japó i es diu Large Helical Device (LHD), mentre que a Espanya, el stellarator TJ-II es troba a les instal·lacions del CIEMAT a Madrid. En aquesta tesi, s'estudien ambdós dispositius per tal de determinar de que depèn que aparegui o que desaparegui el transport de calor turbulent en aquests dispositius, i si hi ha algun tipus de punt en comú.En primer lloc, s'analitza el transport de calor colisional (degut a la col·lisió de les partícules que formen el plasma) mitjançant la introducció d'un model de transport colisional (anomenat neoclàssic) al codi de transport PRETOR-Stellarator. Aquest model es capaç de calcular magnituds físiques tal com difusivitats i camps elèctrics neoclàssics però sense consumir tant de temps com a d'altres tècniques que utilitzen mètodes de Monte Carlo. Dels resultats es desprèn que el transport neoclàssic, tant al TJ-II com al LHD, pot ser important, en plasmes amb baixa densitat i temperatures grans. Ambdós dispositius comparteixen la característica de que apareix, en aquests casos, un gran camp elèctric al centre del plasma que pot ser fa que el transport turbulent disminueixi. Mitjançant la introducció de diferents models pel transport turbulent a PRETOR-Stellarator, s'estudia el transport turbulent als dos dispositius. De l'anàlisi es dedueix que ambdós dispositius poden compartir el mateix tipus de transport (anomenat electromagnètic) i que es degut a les variacions locals del camp magnètic. Tanmateix, fora de la zona central, el LHD té un tipus de transport semblant al que existeix al tokamak JET (Joint European Torus), mentre que el TJ-II continua amb el transport electromagnètic.La reducció del transport turbulent prèviament estudiat és un tema capdal ja que permetria un millor confinament del plasma. S'ha estudiat com el camp elèctric format al centre del plasma pot generar un rotació que disminueix el transport turbulent tant al LHD com al TJ-II. Aquests plasmes es diuen que tenen una barrera interna del transport que redueix el transport turbulent a valors neoclàssics sempre que la densitat sigui prou baixa.Un altre fenomen lligat al transport molt important és el transport no local, que es degut a les correlacions entre parts llunyanes del plasma i que no es pot entendre dintre del context del transport difusió que se sol emprar per a estudiar el plasmes confinats. En el marc d'aquesta tesi s'ha dissenyat un model de transport no local per mitjà d'una convolució sobre el transport neoclàssic. Amb aquest model s'ha aconseguit reproduir molts del efectes no locals que apareixen als plasmes (com ara la ràpida propagació de fenòmens turbulents o la propagació de fronts turbulents que mantenen una forma d'ona ), i que s'han descrit tant al LHD com al TJ-II.Finalment es realitza una comparació entre els dissenys dels reactors de fusió basats en stellarators i tokamaks. Un reactor de fusió stellarator tindria un radi major de 15.5 m i treballaria en mode continu amb alta densitat i baixa temperatura. Les pèrdues d'energia més importants serien, en aquest cas, degudes a la convenció i conducció dins del plasma. El fet que tingui una grandària tan gran el faria molt car de construir. En el cas dels tokamaks, la seva grandària seria més petita, però les pèrdues per radiació ciclotró serien molt grans (degut al règim d'alta temperatura i baixa densitat) i el disseny d'una paret del reactor amb un coeficient de reflexió molt gran fora totalment necessari.

The mining industry desires to cut costs and to operate in more dangerous mines, which is why companies such as Atlas Copco are developing autonomous vehicles. The problem to navigate autonomously is however complex, so the vehicles have in the recent years become more intelligent; the number of computers, actuators and sensors are increasing. For example, an autonomous LHD (Loading – Hauling – Dump) vehicle has sensors including: inertial measurement unit (IMU), odometer, hinge angle sensor, laser range finders and cameras. The parameters for the sensors needs to be calibrated before the vehicle can be used in a mine. There are also a number of electrical currents which needs to be calibrated for the actuators.The calibration of parameters has traditionally been made manually, but Atlas Copco realizes that manual calibration is not feasible once the sales of intelligent mine vehicles increases. Effort is therefore put into automation of the calibration procedures.Interviews with employees were carried out at Atlas Copco to identify the most time consuming procedures during calibration and installation of autonomous mine vehicles. The calibration of steering currents was not only identified as the most time consuming procedure, but also as one of the most complex procedures.The goal of this thesis is to enable easier and quicker installation of mine vehicles. This is done through investigation of methods for automatic calibration of steering currents. The problem is approached from two angles: a grey box model using system identification and a black box model using neural network with resilient backpropagation. The models are compared to a search algorithm, used for simulation of the manual calibration method. In the end, the models are evaluated with regard to performance and ease of implementation.The hypothesis was that the more complex grey box or black box model would have higher accuracy than a simple search algorithm. However, the search algorithm proves to outperform the other models both with regard to accuracy and calibration time, and is also easier to implement. The search algorithm is thus suggested to be implemented instead of a complex model. Moreover, it is suggested that a straightforward mapping of 20 currents may outperform even the search calibration. It is also concluded that calibration of steering currents can be done when the vehicle is standing still.

The mining industry is constantly under pressure to improve productivity, effciency and safety. Although an increased use of automation technology has the potential of con- tributing to improvements in all three factors mines have been relatively slow to make use of automation technology. Automation in the underground mining environment is a challenging prospect for a number of reasons not least of which being the diffculties and associated costs of installing infrastructure in this hazardous environment. The work described in this dissertation focuses on the modelling of a Load-Haul-Dump or LHD vehicle for the purpose of autonomous navigation and control. Considerable progress has been made in automating underground mining vehicles in recent years, and successful test installations have been made. There are still however a number of shortcomings in the existing autonomous underground mine vehicle navigation systems. This dissertation attempts to address some of these problems through the development of a more accurate vehicle model for an LHD vehicle incorporating some vehicle and tyre dynamics thereby potentially reducing the number of sensors and the amount of installed infrastructure necessary to implement the vehicle navigation system. Simulation results are provided for different vehicle modelling techniques and the results are compared and discussed in terms of their suitability for physical implementation in an underground mine. / Dissertation (MEng (Electronic Engineering))--University of Pretoria, 2007. / Electrical, Electronic and Computer Engineering / MEng / unrestricted

Mining is a high-risk industry, so efficiency and safety are key priorities. As mines continue to go deeper and exploit low-grade deposits, bulk mining methods, such as sublevel caving (SLC), have become increasingly important. SLC is suitable for massive steeply dipping ore bodies and is known for its high degree of mechanisation, productivity, and low operational cost. Moreover, technological developments and mechanisation have allowed these methods to be applied at greater depths. In modern mechanised mines Load haul dump (LHD) machines are central to achieving the desired productivity. Therefore, automation of LHDs and their increasing use in mines make it crucial to understand the performance of these machines in actual mining environments. The aim of this research was to understand the differences in the productivity of semiautonomous and manual LHDs and identify how external factors impact the performance of these machines in SLC operations. The research also investigated how LHD operator training could improve the loading efficiency. Performance data for semi-autonomous and manual LHDs were collected from LKAB’s Kiirunavaara mine’s central database, GIRON. These data were used to compare cycle times and payloads of semi-autonomous and manual LHDs. The data were filtered and sorted so that only data where both machine types were operating in the same area (crosscut, ring, and ore pass) were used. To understand the impact of external factors, data on the occurrence of boulders were collected from LKAB’s Malmberget mine by recording videos of LHD buckets, while the data on operator training were obtained by performing baseline mapping and conducting a questionnaire study with the LHD operators at LKAB’s Kiirunavaara mine. The results of the comparative analysis of manual and semi-autonomous LHDs showed the mean payload was 0.34 tonnes higher for manual LHD machines. However, the differences were not consistent across different areas of the mine. Similarly, when comparing the cycle times, in 57% of the studied area, manual LHDs had lower cycle time, while the opposite was true in the remaining 43% of the areas. Therefore, the differences in cycle time and payload due to mode of operation are not conclusive, meaning that one machine type does not completely outperform the other. This highlights the importance of understanding the external factors that cause such differences. Moreover, the findings emphasize the need to upgrade LHD operator training based on pedagogical principles and the inclusion of new technologies to enhance loading efficiency and increase overall productivity.

Mine automation has been in development since the 1980s and began to be implemented in the 1990s with the biggest drivers being safety, reduced maintenance and increased productivity. Automation is used in many different mining methods performing a variety of tasks. However, very few studies have been conducted regarding the performance of automatic vehicles in real world mines, neither has much research been done when comparing automated and manual loading.   The purpose of this thesis is twofold. First it is to identify and produce metrics that can be used to compare automatic and manual loading in an underground mining environment. A literary study is presented as a basis for these metrics where the development history is chronicled and the mechanics by which an automated system controls an automatic vehicle is explained. Also included is a description of different mining methods and the part that automation plays in them.   Secondly, the goal is to use these metrics in a real world case study of automated loading in an actual operational mine. The Garpenberg mine, owned by Boliden Minerals, is an underground metal mine located in Dalarna, Sweden, and mining has been done there since the 1200s. Load-Haul-Dump (LHD) machines are used to load and haul ore ether using automation or tele operation. For this study information is extracted from Bolidens internal databases to calculate the metrics which are then used to analyze the performance and reliability of automated loaders, and also to compare manual and automatic loading.   There are mainly three types of metrics that are relevant to automatic and manual loading, these being time related metrics, production related metrics and reliability related metrics.   Since the LHDs dealt with in this thesis are operated both manually and automatically the main use of the time related metrics is to find the relationship between modes of operation in regards to engine hours spent in action, the amount and character of downtime that occurred during the analyzed time span, and the utilization of automatic LHDs during the workday. The most straightforward comparison between manual and automatic loading is the production, i.e. the tonnage of loaded material per unit time. In this thesis production will be analyzed per hour and per loading activity (which run between 3 and 4 hours). Lastly automated and manual loading will be compared on the basis of availability and maintenance, the reason being that LHDs are driven in different ways depending on the mode of operation.   The results show that automatic loading consists of between 14 and 29% of production time while contributing to between 17 and 28% of downtime. No clear connection can be seen between downtime and the relationship of automatic to manual loading, as the difference is not bigger than 10% either way. Manual loading constitutes between 2500 and 3250 engine hours, while time spent during automatic loading constitutes between 420 and 1095 engine hours. The majority of all downtime is not specific to either mode of operation, although automatic specific stops constitutes up to 50% of total downtime for two of the LHDs studied. The distribution of loading activities is similar for both manual and automatic loading, with the number of concurrent activities dipping during lunch breaks and stopping entirely during shift changes. Manual loading peaks around 1000 concurrent jobs while automatic peaks at just fewer than 200.   Regarding production the results show that manual loading is more effective in the short term, as three out of four LHDs has had a higher tonnage loaded per hour. However, when locking at the tonnage loaded per activity, automatic loading catches up to manual loading and produces more tonnage in the long term, with three out of four LHDs getting this higher production.   One interesting result can be found in regards to fuel economy, as one of the LHDs show a reduced consumption of fuel while at the same time having had the largest percentage of time spent in automatic mode. No clear connection can be seen with the rest of the LHDs however, as they show no clear connection between time spent in ether mode of operation and the amount of fuel consumed.   Automatic loading proved to have slightly higher availability than manual loading. In all cases however, the difference in no more than 10% and both modes of operation is above 90% availability. The higher availability of automatic loading is attributed to the fact that manual loading constitutes much more time than automatic loading, and thus there has been more time for breakdowns and production stops to occur for manual loading. The relationship of preventive and corrective maintenance is the same for all four LHDs irrespective of amount of time spent in ether operating mode. Preventive maintenance jobs accounts for more than 90% of the number maintenance actions for all LHDs.   When analyzing what kinds of production stops are the most prevalent, there are differences between manual and automatic loading. For manual loading the most common stops are those that have to do with external circumstances in the mine such as blocked access and fallen boulders, and those to do with minor breakdowns of the LHD. For automatic loading the most common stops are those to do with the automatic system and the equipment used to operate the automated LHD, followed by those caused by external circumstances, similarly to manual loading. Automatic loading has proportionally fewer stops than manual loading in all categories except those unique to automation, which is in turn the biggest category of all production stops.   The conclusions that can be drawn from these results are that automatic loading can outperform manual loading in the long term, but that continuous uninterrupted loading activates are important to achieve this. Automatic and manual loading show comparable reliability when it comes to maintenance and repairs (serious breakdowns are very rare). Availability and the relationship of preventive and corrective maintenance are similar between both modes of operation. The analysis of production stops show that the biggest problem with automatic loading is the automatic systems and the specialized equipments inability to handle the underground environment. Problems with recorded routes and falsely tripped safety systems are the most common stops.       Recommendations to Boliden Minerals regarding the automatic system consist of improving remote troubleshooting and streamlining of problem solving dealing with automation software and hardware. Steps should also be takes towards tailoring the underground environment to better suit automation.   Suggestions to further research consist of deeper studies of all the metrics presented in this thesis to better analyze the role of automation in the global mining industry. Another avenue of study is the combination of the findings in this thesis with the actual environment and layout in the Garpenberg mine to better understand the connection between operating environment and the reliability and productivity of the automatic system.