152 1. INTRODUCTION 1.1 Energy Transition and Underground Development Underground mining is undergoing structural change driven by deeper orebodies, increasing cost pressure, and rising expectations regarding environmental and safety performance. Electrification of mining equipment, integration of renewable energy sources, and regulatory frameworks such as the EU Corporate Sustainability Reporting Directive (European Union, 2022) require measurable improvements in energy efficiency and risk reduction across the project life cycle. The increasing demand for critical minerals required for clean energy technologies further intensifies the need for efficient and predictable underground development. Development drives represent a critical phase in underground projects. Their construction duration directly influences time-to-ore, capital exposure, and early cash flow. At the same time, development activities contribute significantly to energy consumption and operational risk. As a result, excavation methods are increasingly evaluated not only by cost per meter, but by their impact on safety performance, energy intensity, schedule reliability, and their implications for project valuation and capital efficiency. 1.2 Structural Limits of Cyclic Excavation Conventional drill-and-blast excavation remains the dominant method in underground mining. However, its cyclic nature introduces structural limitations. Each excavation cycle requires drilling, charging, blasting, ventilation clearance, scaling, and ground support before the next round can begin. This sequence creates inherent discontinuity in advance rates and exposes personnel repeatedly to the excavation face. Irregular tunnel cross section geometries caused by blasting increase overbreak and ground support variability. The combination of diesel-powered equipment and blast fumes drives high ventilation demand, particularly during clearance phases. These characteristics result in fluctuating energy consumption profiles, operational uncertainty, and elevated safety exposure during face re-entry and explosive handling. While incremental improvements have been achieved, the fundamental cyclic structure of the process remains unchanged. 1.3 Continuous Excavation as a System Alternative Mechanized tunnelling with Tunnel Boring Machines (TBMs) replaces cyclic excavation with a continuous, electrically powered process. Rock fragmentation, muck removal, and ground support installation are performed in an integrated and largely parallel workflow, rather than in sequential stages. This coordinated process architecture reduces interruptions, minimizes repeated face exposure, and stabilizes advance performance. The
RkJQdWJsaXNoZXIy MTM0Mzk2