Henry Krumb Lecture Series

Fiber-reinforced concrete (FRC) tunnel linings in transit systems are typically designed based on accidental fire loads. Conventional methods often rely on standard temperature-time curves, which can overestimate fire loading and lining thickness. Due to the impracticality of conducting full-scale train car fire tests for every system, Computational Fluid Dynamics (CFD) offers a valuable alternative. This study presents a CFD-based methodology to evaluate tunnel wall temperatures during a 15 MW train car fire scenario in an active megaproject. The analysis incorporates convection, conduction, and radiation heat transfer. The maximum wall temperature reached 735.6 °C and was used to develop a temperature-time curve for FRC lining design. Results were validated against similar full-scale tunnel fire tests. This approach enables more accurate, cost-effective tunnel fire design by reducing over-conservatism and aligning with real-world conditions.

Mine plans are constantly changing to adapt to actual ore grade distributions which are only approximately known at the time the original plan is created. First, the presentation will discuss theory and recent research into mine plan risk assessment and grade uncertainty characterization using geostatistical conditional simulation. Then, the practice of managing mine plan risk will be discussed via stories of mine planning lessons learned from working with several executives who have been inducted into the National Mining Hall of Fame.

The raise bore method of vertical mine development has been successfully employed in underground mines for over sixty years, evolving from its origins where only small diameter raises under six feet were possible, to now enabling excavations greater in diameter and length. This progression has allowed for the construction of productive hoisting shafts and a wider array of complex projects, thanks to improvements in technology that enhance vertical control during drilling. Successful raise boring requires careful consideration of factors such as the proposed excavation’s dimensions, access, ground stability, and waste handling. Two recent landmark projects demonstrate the method’s capabilities: one achieved the longest single-pass raises in the Americas at 3,530 feet, and another accomplished a large diameter of 26.6 feet while pioneering a variable-diameter approach to optimize shaft lining. These achievements highlight raise boring’s adaptability and its critical role in modern underground mining.

Environmentally responsible and competitive nickel sulfate hexahydrate production is vital to the energy transition. This study presents a process-based life cycle assessment of six production pathways: hydrometallurgical (i) mixed sulfide precipitate in Brazil, (ii) mixed hydroxide precipitate in Australia, (iii) Direct Nickel process in Australia; and pyrometallurgical (iv) nickel pig iron in Indonesia, (v) Class 1 nickel in Canada, and (vi) the Caron method in Cuba. The lowest carbon footprint (6.72 kg CO₂eq/kg) was from the Canada-Norway pyrometallurgical route. The Direct Nickel process showed 5.01 kg CO₂eq/kg excluding electricity. Network analysis of CO₂eq emissions identified material vulnerabilities and environmental hotspots. Transitioning to renewable energy, particularly in Indonesia’s coal-powered Rotary Kiln-Electric Furnace process, could significantly reduce global warming potential—from 86.4 to 45 kg CO₂eq/kg with 50% hydropower. These findings support low-carbon, responsible production aligned with clean energy goals.

Dust-related lung disease remains a serious concern among mine workers. While exposure to respirable dust is typically measured on the basis of mass, dust characteristics at the particle level (e.g., size, surface chemistry) are increasingly of interest. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) enables high-resolution analysis of particles, and our past work has demonstrated the complex nature of respirable dust–including the presence of agglomerates and mixed particles, which could have important implications for exposure assessment and health outcomes. To increase the efficiency of data collection and limit user-bias in interpretation, our latest research is using advanced SEM-EDX tools like the mineral liberation analyzer (MLA). MLA was originally developed for ore characterization, but we are leveraging its pixel-by-pixel capability to map and classify dust particles. Results on respirable coal mine dust samples indicate that agglomerates or mixed particles can often account for the majority of all particles present.

Recent research in our laboratory highlights the potential of a unique, diatom-dominated photosynthetic wetland for attenuating a broad range of metal(loid)s. This passive, open-water system offers chemical-free alkalinization and oxidation, making it a promising complement to engineered treatment technologies. Bench-scale studies demonstrate that integrating this wetland with membrane processes can enhance cost-effective removal of arsenic and boron. Building on this, we evaluated biological oxidation followed by ferric flocculation for broader metal removal. Additionally, reversing the treatment sequence—using mild chemical dosing to raise acid mine drainage pH from 3 to 5 before wetland transit—shows promise for further passive treatment and pH stabilization. These findings support a hybrid approach that combines nature-based and active technologies to improve sustainability and performance in mine water treatment.