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In 2006, Congress passed the MINER Act requiring mine operators to submit an emergency response plan that included post-accident communications and tracking systems to MSHA within three years of the Act. These systems were required to be designed for maximum survivability after a catastrophic event, such as a fire or explosion, and to be permissible (meets MSHA criteria for explosion-proof). At that time, no commercially available systems existed that met these standards. Several companies undertook developing new, or enhancing existing, technologies to meet these requirements. This research presents the results of a study that was conducted to determine the present day types of systems being used, along with their average annual worker hours, coal production, number of mechanized mining units, and type of communications and tracking systems installed. Furthermore, 10 mines were visited to obtain detailed information related to the various technologies. It was found the most influential parameters on system selection include MSHA district, mining method, and number of underground workers.

In this thesis, a new method has been proposed for calculating the frequencydependent parameters of underground cables. The method uses full wave formulation for calculating the modal electromagnetic fields and corresponding voltages and currents and then extracting frequency-dependent per unit length parameters of underground cables. The proposed method can be used for any cross-sectional shape of cables.

Excavation activities like open cutting and tunneling work may cause ground movements. Many of these activities are performed in urban areas where many structures and facilities already exist. These activities are close enough to affect adjacent structures. It is therefore important to understand how the ground movements due to excavations influence nearby structures. The goal of the proposed research is to investigate and develop analytical methods for addressing uncertainty during observation-based, adaptive design of deep excavation and tunneling projects. Computational procedures based on a Bayesian probabilistic framework are developed for comparative analysis between observed and predicted soil and structure response during construction phases. This analysis couples the adaptive design capabilities of the observational method with updated reliability indices, to be used in risk-based design decisions. A probabilistic framework is developed to predict three-dimensional deformation profiles due to supported excavations using a semi-empirical approach. The key advantage of this approach for practicing engineers is that an already common semi-empirical chart can be used together with a few additional simple calculations to better evaluate three-dimensional displacement profiles. A reliability analysis framework is also developed to assess the fragility of excavation-induced infrastructure system damage for multiple serviceability limit states. Finally, a reliability analysis of a shallow circular tunnel driven by a pressurized shield in a frictional and cohesive soil is developed to consider the inherent uncertainty in the input parameters and the proposed model. The ultimate limit state for the face stability is considered in the analysis. The probability of failure that exceeding a specified applied pressure at the tunnel face is estimated. Sensitivity and importance measures are computed to identify the key parameters and random variables in the model.

Thesis (Ph.D.)--University of South Australia, 1996.