This work focuses on the operational and safety issues associated with karst voids in large opening underground mines. Issues include water inrush, structural instability, and engineering uncertainty in these environments. Coupled with the fracturing prevalent in folded sedimentary rocks, karsts are complex and challenging ground control risks. Traditional methods of predicting karst void locations such as probe-drilling are impeded by the inconsistent spatial distribution and variable sizes of the features. Ground penetrating radar (GPR) is a geophysical technique that transmits radio waves into a medium and subsequently detects reflected waves via a receiver. The travel time and energy of received signals are then processed and interpreted. The difference in material properties between limestone and open karst voids causes strong reflections. This work summarizes a series of 2D and 3D GPR surveys for karst void mapping within a mine pillar and within sill pillars between mine levels in a large opening underground limestone mine. In this case study mine, karst voids are hazardous ground control risks that interact with geologic discontinuities, creating free blocks within the rock mass. As tunnels are advanced via blasting, unknown karst voids may be exposed and pose risks to mining personnel. The karst voids also form a hydrogeological network of water reservoirs with spatial locations throughout the rock mass that are difficult to predict with traditional methods such as drilling. While GPR has been utilized throughout several industries for anomaly detection, mapping, and validating other geophysical data sets, this technique has not seen the same proliferation within the mining industry. Regarding published literature, there is a lack of works that detail the applicability of GPR in underground mining scenarios. The aim of this work is to expand on previous methodologies establishing GPR as a useful tool in underground mining applications, and to discuss the benefits and limitations GPR data in such scenarios. / Master of Science / This work focuses on the operational and safety issues associated with karst voids in large opening underground mines. Typical issues include water flooding into the tunnels and rocks falling out from the roof and walls, among other things. Sedimentary rock structures sometimes are geologically complex, and karst voids only add to that complexity. Engineers usually predict karst void locations with drilling or statistics, but this is often challenging as karst voids have various shapes and orientations. Ground penetrating radar (GPR) is a geophysical technique that sends electric signals into the rock; these signals can reflect off of karst voids and other anomalies. The travel time and energy of signals that come back to the antennas are then processed and interpreted. The difference in material properties between limestone and open karst voids causes strong reflections. This work shows a series of 2D and 3D GPR surveys for karst void mapping within a pillar in a stone mine and also below the floor of mine tunnels. In this mine, karst voids are very dangerous and the miners spend significant time and resources to ensure the tunnels walls are stable. As tunnels are blasted, hidden karst voids may be exposed and pose unpredicted risks to miners. The karst voids are also connected by cracks and discontinuities, providing a path for water to travel along. While GPR has been used in various ways among the construction, civil engineering, and tunneling industries, there is not enough literature pertaining to its benefits for mines. The goal of this work is to grow the available literature on GPR in mining and to talk about the best practices for GPR use as a means of improving health and safety for miners underground.

A majority of underground coal mine disasters in the United States are due to explosions. Current atmospheric monitoring system (AMS) practices in the US could be enhanced to facilitate data sharing and learning of the entire work force. With the inclusion of additional atmospheric monitoring and data collecting, meaningful analysis can be realized and shared with the workforce. AMS data can be utilized to advance the understanding of underground atmospheres for the entire workforce along with adding to the knowledge base for preventative planning. An AMS interface ADAMAS is suggested to facilitate this conglomeration and sharing of the data visually, so that it can be quickly processed and applied in their daily decisions. An emerging sensor technology for underground mining, fiber optics is explored and tested in emergency, or fire and explosion situations. The fiber optic methane sensor performed well in smoke only showing a slow in response time due to soot on the filter. The ADAMAS interface was tested in a large population of underground coal miners. The population varied in age, job, classification, and experience. They all primarily found it to be easy to use and helpful to them. Concerns arose when asked how this will facilitate an improved relationship with regulatory agencies. There is trepidation when it comes to additional atmospheric information sharing, that it may not be used advance understanding of mine atmospheres. The AMS data collected is individual to each mine site but can assist in the understanding of underground atmosphere as a whole. Moving forward, regulatory bodies should use this as a stepping point to consider how this information can be used to advance the field of mine ventilation and also the health and safety of the miner. / Ph. D.

O método de lavra câmaras e pilares é muito utilizado em minas de carvão subterrâneo, principalmente nos estados de Santa Catarina e Paraná, onde todas as minas subterrâneas utilizam este método. Vale ressaltar, porém, que o método apresenta recuperações de lavra abaixo de 50%, dependendo do tamanho dos pilares, e a produtividade é altamente dependente de uma boa concatenação das operações unitárias. Entre os aspectos relacionados à eficiência produtiva, a distância de transporte é um item preponderante no desempenho do sistema. Devido à profundidade da lavra, há um aumento do tamanho dos pilares de sustentação da mina, e assim, surgem problemas relacionados ao incremento no tempo de ciclo de transporte dos equipamentos. O aumento da distância de transporte entre uma frente de lavra com material desmontado e o alimentador/britador primário, reduz o resultado da produção de um conjunto de equipamentos. Em mineração a céu aberto, este tipo de problema é resolvido com o aumento da frota de transporte, todavia, na mineração de carvão subterrânea, não é possível aumentar de forma irrestrita a quantia de máquinas em subsolo, pois impactaria diretamente na necessidade de incremento da vazão de ar, assim como, limitação de espaço para o tráfego de equipamentos. A aproximação da distância do ponto de descarga para um local adjacente às frentes de serviço é uma alternativa para solucionar a necessidade de incremento da frota de produção. No entanto, o ponto de mudança deve ser avaliado de forma consistente para determinar o momento mais adequado para que essa reaproximação proporcione um resultado ótimo. Este estudo buscou compreender esta etapa necessária ao processo produtivo, utilizando técnicas de regressão para analisar o impacto da distância de transporte na capacidade produtiva. O problema foi modelado e foram propostas alternativas que forneçam um sequenciamento de lavra capaz de amenizar os problemas decorrentes do aumento da distância de transporte das frentes de lavra aos respectivos pontos de descarga. Os resultados demonstraram que a distância de transporte tem influência direta na produção, mas não somente a distância máxima, mas também, uma distância mínima que deve ser respeitada para obter maior produtividade quando se tem a associação de equipamentos de produção. É possível concluir com este estudo que a distância de transporte tem impacto relevante e deve ser considerada, não tão somente no sequenciamento, mas também no dimensionamento da frota e consequente capacidade produtiva. / The room and pillar mining method is widely used in underground coal mines. Santa Catarina and Paraná where all underground mines use this method. Indeed, the method has mining recoveries below 50% and the productivity is highly dependent on a good concatenation of unit operations. Among the aspects related to production efficiency, the transport distance is an important item on system performance. Due to the depth of the mine, there is an increment in the size of the underground supporting pillars, and consequently, problems related to the increase in equipment cycle times. The increase of the transportation distance between mining faces and the primary crusher reduces the result of a set of production equipment. In open pit mining, this problem is solved by increasing the haulage fleet, however, in the underground coal mining, the number of machines cannot be increased indefinitely because it would impact directly on the need of increased air flow. Therefore, the approximation of the distance from the discharge point to an adjacent location from the mining faces is an alternative to address the need of increased production fleet. However, the relocation point must be evaluated consistently to determine the most appropriate time to get the most from this approach. The goal of the study was to understand this imperative step for the production process, using regression techniques to analyze the impact of transport distance in productive capacity. Based on the experimental design used in this study, alternative proposals provide a mining sequence able to mitigate the problems from increasing transportation distance from mining faces to their discharge points. The results show that the transport distance has directly influence on the production, and it is not limited to the maximum distance. Likewise, a minimum distance must be respected for higher productivity when you have the combination of production equipment. So, it is possible to conclude that the transport distance has a significant impact and must be considered not only during the sequencing, but also when determining the fleet size and consequent production capacity.

Development drilling is used in underground mining to create access tunnels. A common method involves using a drilling rig, known as a jumbo, to drill holes into the face of a tunnel. Jumbo drill rigs have two or more articulated arms with drills as end-effectors, that extend outwards from a vehicle. Once drilled, the holes are charged with explosives and fired to advance the tunnel. There is an ongoing imperative within the mining industry to reduce development times and reducing time spent drilling is seen as the best opportunity for achieving this. Notwithstanding that three-boom jumbos have been available for some years, the industry has maintained a preference for using jumbo rigs with two drilling booms. Three-boom machines have the potential to reduce drilling time by as much as one third, but they have proven difficult to operate and, in practice, this benefit has not been realized. The key difficulty lies in manoeuvering the booms within the tight confines of the tunnel and ensuring sequencing the drilling of holes so that each boom spends maximum time drilling. This thesis addresses the problem of optimally sequencing multi-boom jumbo drill rigs to minimize the overall time to drill a blast hole pattern, taking into account the various constraints on the problem including the geometric constraints restricting motion of the booms. The specific aims of the thesis are to: ² develop the algorithmic machinery needed to determine minimum- or near-minimum-time drill assignment for multi-boom jumbos which is suitable for "real-time" implementation; ² use this drill pattern assignment algorithm to quantify the benefits of optimal drill pattern assignment with three-boom jumbos; and ² investigate the management of unplanned events, such as boom breakdowns, and assess the potential of the algorithm to assist a human operator with the forward planning of drill-hole selection. Jumbo drill task assignment is a combinatorial optimization problem. A methodology based around receding horizon mixed integer programming is developed to solve the problem. At any time the set of drill-holes available to a boom is restricted by the location of the other booms as well as the tunnel perimeter. Importantly these constraints change as the problem evolves. The methodology builds these constraints into problem through use of a feasibility tensor that encodes the moves available to each boom given configurations of other booms. The feasibility tensor is constructed off-line using a rapidly exploring random tree algorithm. Simulations conducted using the sequencing algorithm predict, for a standard drill-hole pattern, a 10 - 22% reduction in drilling time with the three-boom rig relative to two-boom machines. The algorithms developed in this thesis have two intended applications. The first is for automated jumbo drill rigs where the capability to plan drilling sequences algorithmically is a prerequisite. Automated drill rigs are still some years from being a reality. The second, and more immediate application is in providing decision support for drill rig operators. It is envisaged that the algorithms described here might form the basis of a operator assist that provides guidance on which holes to drill next with each boom, adapting this plan as circumstances change.

The onset of an explosion in an underground mining environment is a threat that has over years attracted a lot of attention. Much of this attention has focused on either arresting the explosion after it has been initiated or preventing the initiation. The methods devised have proved successful in most cases, but on the odd occasion that they fail, the end results can be disastrous. There have been fatalities from underground mining explosions as a result of fires burning and sapping all the oxygen in the atmosphere leading to asphyxiation. A different approach to arresting these explosions would enhance safety in the face of increased productivity. A novel method using an explosion door with a porous media acting as a shock wave attenuator and arresting the flames has been introduced. This research investigates the ability of the porous media used in the explosion door to withstand explosions. The performance of the porous media is crucial, as its failure would render the explosion door useless. In order to assess the performance of the porous media, a shock tube was built capable of generating shock waves with a Mach number of 1.5. By placing samples of the porous media within the test section of the shock tube, pressure measurements were taken fore and aft of the porous media as it was impinged upon by the shock wave. Tests were also conducted using thin orifice plates to provide data for comparing the performance characteristics of the porous media. Computational fluid dynamics (CFD) simulations of the porous media and the orifice plates were performed to validate the experimental work as well providing graphic detail of the flow around the test specimen. The work presented in this thesis makes a contribution to the efforts towards the provision of a safe underground environment. This contribution is achieved by investigating the performance of the porous media to be used in an explosion door and correlating the performance of the porous media with thin orifice plates. The porous media in the work presented here is currently used in the castings industry and its application as a shock wave attenuator and fire arrester would contribute greatly to the well being of all people working underground.

O método de lavra câmaras e pilares é muito utilizado em minas de carvão subterrâneo, principalmente nos estados de Santa Catarina e Paraná, onde todas as minas subterrâneas utilizam este método. Vale ressaltar, porém, que o método apresenta recuperações de lavra abaixo de 50%, dependendo do tamanho dos pilares, e a produtividade é altamente dependente de uma boa concatenação das operações unitárias. Entre os aspectos relacionados à eficiência produtiva, a distância de transporte é um item preponderante no desempenho do sistema. Devido à profundidade da lavra, há um aumento do tamanho dos pilares de sustentação da mina, e assim, surgem problemas relacionados ao incremento no tempo de ciclo de transporte dos equipamentos. O aumento da distância de transporte entre uma frente de lavra com material desmontado e o alimentador/britador primário, reduz o resultado da produção de um conjunto de equipamentos. Em mineração a céu aberto, este tipo de problema é resolvido com o aumento da frota de transporte, todavia, na mineração de carvão subterrânea, não é possível aumentar de forma irrestrita a quantia de máquinas em subsolo, pois impactaria diretamente na necessidade de incremento da vazão de ar, assim como, limitação de espaço para o tráfego de equipamentos. A aproximação da distância do ponto de descarga para um local adjacente às frentes de serviço é uma alternativa para solucionar a necessidade de incremento da frota de produção. No entanto, o ponto de mudança deve ser avaliado de forma consistente para determinar o momento mais adequado para que essa reaproximação proporcione um resultado ótimo. Este estudo buscou compreender esta etapa necessária ao processo produtivo, utilizando técnicas de regressão para analisar o impacto da distância de transporte na capacidade produtiva. O problema foi modelado e foram propostas alternativas que forneçam um sequenciamento de lavra capaz de amenizar os problemas decorrentes do aumento da distância de transporte das frentes de lavra aos respectivos pontos de descarga. Os resultados demonstraram que a distância de transporte tem influência direta na produção, mas não somente a distância máxima, mas também, uma distância mínima que deve ser respeitada para obter maior produtividade quando se tem a associação de equipamentos de produção. É possível concluir com este estudo que a distância de transporte tem impacto relevante e deve ser considerada, não tão somente no sequenciamento, mas também no dimensionamento da frota e consequente capacidade produtiva. / The room and pillar mining method is widely used in underground coal mines. Santa Catarina and Paraná where all underground mines use this method. Indeed, the method has mining recoveries below 50% and the productivity is highly dependent on a good concatenation of unit operations. Among the aspects related to production efficiency, the transport distance is an important item on system performance. Due to the depth of the mine, there is an increment in the size of the underground supporting pillars, and consequently, problems related to the increase in equipment cycle times. The increase of the transportation distance between mining faces and the primary crusher reduces the result of a set of production equipment. In open pit mining, this problem is solved by increasing the haulage fleet, however, in the underground coal mining, the number of machines cannot be increased indefinitely because it would impact directly on the need of increased air flow. Therefore, the approximation of the distance from the discharge point to an adjacent location from the mining faces is an alternative to address the need of increased production fleet. However, the relocation point must be evaluated consistently to determine the most appropriate time to get the most from this approach. The goal of the study was to understand this imperative step for the production process, using regression techniques to analyze the impact of transport distance in productive capacity. Based on the experimental design used in this study, alternative proposals provide a mining sequence able to mitigate the problems from increasing transportation distance from mining faces to their discharge points. The results show that the transport distance has directly influence on the production, and it is not limited to the maximum distance. Likewise, a minimum distance must be respected for higher productivity when you have the combination of production equipment. So, it is possible to conclude that the transport distance has a significant impact and must be considered not only during the sequencing, but also when determining the fleet size and consequent production capacity.

Made available in DSpace on 2015-03-26T13:27:53Z (GMT). No. of bitstreams: 1 texto completo.pdf: 5961101 bytes, checksum: 1b2e71817a678efd1be8ae17541686d2 (MD5) Previous issue date: 2009-09-22 / This dissertation describes the Vazante underground mine rock mass and some important breccias geomechanics features, or bimrocks, which occur in the underground. Systematic geologic-geotechnics mappings of the main levels of the underground mine was carried out, allowing the individualization of four families of main discontinuities, besides the preserved sedimentary bedding and the foliation. The mappings were done following the geomechanics classification RMR and the Q system, supplying correlation between the methods for Vazante's lithotypes. A new campaign of uniaxial tests for the determination of intact rock strength was carried out and the RQD values for each classified area had been determined by statistics analyses. The results were discussed according to each parameter and peculiarities found in each distinct rock mass. The breccias, a rock type which is not very accessible in the geotechnical literature, had been characterized according to the volumetric block proportion (VBP) and strength to simple compression. The values of VBP had been found from the analyses obtained with the aid of the Leica Qwin software for the binarization of the digitalized images. There has also been presented the correlation between the simple compression and the percentages of the main chemical elements that constitutes the Vazante breccias, such as zinc, iron, calcium, magnesium and silicon. / Esta dissertação descreve o maciço rochoso da mina subterrânea de Vazante e algumas importantes características geomecânicas das brechas, ou bimrocks, que ocorrem em subsolo na área da mina. Realizaram-se mapeamentos geológico-geotécnicos sistemáticos dos principais níveis da mina, que permitiram a individualização de quatro famílias de descontinuidades principais, além do acamamento sedimentar preservado e a foliação. Os mapeamentos foram executados seguindo a classificação geomecânica RMR e o Sistema Q, fornecendo correlações entre esses métodos para os litotipos de Vazante. Foi realizada uma nova campanha de ensaios uniaxiais para determinação da resistência da rocha intacta e análises estatísticas para setorização do RQD. Os resultados encontrados são discutidos em função de cada parâmetro e particularidades encontradas em cada maciço rochoso. As brechas, tipo de rocha pouco descrito na literatura geotécnica, foram caracterizadas em função da proporção volumétrica de blocos (VBP) e resistência à compressão uniaxial. Os valores de VBP foram obtidos a partir de análises realizadas com o auxílio do software Leica QWin para binarização das imagens digitalizadas. São apresentadas também as correlações entre resistência à compressão simples e os teores dos principais elementos químicos constituintes das brechas de Vazante, como zinco, ferro, cálcio, magnésio e silício.

O método de lavra câmaras e pilares é muito utilizado em minas de carvão subterrâneo, principalmente nos estados de Santa Catarina e Paraná, onde todas as minas subterrâneas utilizam este método. Vale ressaltar, porém, que o método apresenta recuperações de lavra abaixo de 50%, dependendo do tamanho dos pilares, e a produtividade é altamente dependente de uma boa concatenação das operações unitárias. Entre os aspectos relacionados à eficiência produtiva, a distância de transporte é um item preponderante no desempenho do sistema. Devido à profundidade da lavra, há um aumento do tamanho dos pilares de sustentação da mina, e assim, surgem problemas relacionados ao incremento no tempo de ciclo de transporte dos equipamentos. O aumento da distância de transporte entre uma frente de lavra com material desmontado e o alimentador/britador primário, reduz o resultado da produção de um conjunto de equipamentos. Em mineração a céu aberto, este tipo de problema é resolvido com o aumento da frota de transporte, todavia, na mineração de carvão subterrânea, não é possível aumentar de forma irrestrita a quantia de máquinas em subsolo, pois impactaria diretamente na necessidade de incremento da vazão de ar, assim como, limitação de espaço para o tráfego de equipamentos. A aproximação da distância do ponto de descarga para um local adjacente às frentes de serviço é uma alternativa para solucionar a necessidade de incremento da frota de produção. No entanto, o ponto de mudança deve ser avaliado de forma consistente para determinar o momento mais adequado para que essa reaproximação proporcione um resultado ótimo. Este estudo buscou compreender esta etapa necessária ao processo produtivo, utilizando técnicas de regressão para analisar o impacto da distância de transporte na capacidade produtiva. O problema foi modelado e foram propostas alternativas que forneçam um sequenciamento de lavra capaz de amenizar os problemas decorrentes do aumento da distância de transporte das frentes de lavra aos respectivos pontos de descarga. Os resultados demonstraram que a distância de transporte tem influência direta na produção, mas não somente a distância máxima, mas também, uma distância mínima que deve ser respeitada para obter maior produtividade quando se tem a associação de equipamentos de produção. É possível concluir com este estudo que a distância de transporte tem impacto relevante e deve ser considerada, não tão somente no sequenciamento, mas também no dimensionamento da frota e consequente capacidade produtiva. / The room and pillar mining method is widely used in underground coal mines. Santa Catarina and Paraná where all underground mines use this method. Indeed, the method has mining recoveries below 50% and the productivity is highly dependent on a good concatenation of unit operations. Among the aspects related to production efficiency, the transport distance is an important item on system performance. Due to the depth of the mine, there is an increment in the size of the underground supporting pillars, and consequently, problems related to the increase in equipment cycle times. The increase of the transportation distance between mining faces and the primary crusher reduces the result of a set of production equipment. In open pit mining, this problem is solved by increasing the haulage fleet, however, in the underground coal mining, the number of machines cannot be increased indefinitely because it would impact directly on the need of increased air flow. Therefore, the approximation of the distance from the discharge point to an adjacent location from the mining faces is an alternative to address the need of increased production fleet. However, the relocation point must be evaluated consistently to determine the most appropriate time to get the most from this approach. The goal of the study was to understand this imperative step for the production process, using regression techniques to analyze the impact of transport distance in productive capacity. Based on the experimental design used in this study, alternative proposals provide a mining sequence able to mitigate the problems from increasing transportation distance from mining faces to their discharge points. The results show that the transport distance has directly influence on the production, and it is not limited to the maximum distance. Likewise, a minimum distance must be respected for higher productivity when you have the combination of production equipment. So, it is possible to conclude that the transport distance has a significant impact and must be considered not only during the sequencing, but also when determining the fleet size and consequent production capacity.

Underground coal mining operations induce ground movements, which may impact overlying hydrogeologic systems. Potential impacts mainly include changes in the hydraulic conductivity of overlying strata, decreasing of the hydraulic head and changes in water flow. The present research quantifies potential hydrogeologic impacts caused by underground mining through modeling of pre- and post-mining hydrogeologic systems. Three-dimensional conceptual hydrogeologic models were constructed with the Processing Modflow for Windows software package (PMWiN). The models are based on an actual case study, but were simplified in terms of geometry and material properties. Water flow was simulated under changing hydrogeologic properties. A number of scenarios were investigated including models with horizontal or inclined topography, featuring an aquifer overlying two longwall panels. The hydrogeologic properties of the models were estimated based on empirical relationships between the post-mining hydraulic conductivity and strain in the overburden. The strain regime in the overburden was estimated using the Surface Deformation Prediction System (SDPS) package, which allows calculation of surface deformations due to underground coal mining. The research focuses on changes in hydraulic heads; results indicate that hydraulic heads may decrease over undermined areas and may rebound as mining ceases. Water infiltration may occur from higher located overburden formations to lower formations due to mining induced changes in hydrogeologic properties.

Due to an increasing concern of the introduction of greenhouse gas (GHG) regulations in many jurisdictions, the underground mining industry is in high demand to tackle climate change through innovative measures. In order to stay competitive, cope with rising energy costs and GHG regulations, mining companies will have to consider the alternative to go fully electric. As underground mines progress through time they are becoming deeper and deeper, resulting in longer haulage distances and thus an increasing energy demand. The research in this thesis was conducted to analyze and develop a simulation tool to investigate the replacement of conventional diesel haulage trucks with battery electric trucks that include a fast-charging capability in an underground mine environment. The results show that there is a major difference in the achievable production rates depending on the mine topography and a need for opportunity charging. Furthermore, the developed tool could aid in decision making and provide a good frame of reference of the feasibility of replacing an existing diesel operation by a battery electric one.