4.1 Enabling faster development without sacrificing safety The primary achievement of the ICS trial was demonstrating that development cycles can be significantly shortened without increased risk, provided the support system is engineered to perform quickly. In fact, safety was enhanced: workers were exposed to unsupported ground for a shorter duration, and the immediate application of shotcrete reduced the likelihood of ground falls. This confirms conclusions from earlier studies (e.g., Jenkins et al., 2005; Bernard, 2010) that rapid-shotcrete systems can maintain or improve ground stability when properly applied. A key factor was the attainment of 1 MPa early strength, which appears to be a critical threshold for safe re-entry in many mines (e.g., EFNARC, 2009). Achieving this within circa an hour represents a dramatic improvement over typical unsupported re-entry times. It underscores how advancements in admixture technology (e.g., modern alkali-free accelerators) and mix design can push the boundaries of shotcrete performance. However, it must be noted that ICS may not be suitable in all conditions; success at Inmaculada was aided by the fact that the rock, while weak, did not exhibit heavy water inflow or squeezing ground, conditions that could complicate immediate shotcreting. Thus, careful assessment of geotechnical conditions is essential before adopting ICS broadly. 4.2 Integration and synergy of support elements: One often overlooked aspect of implementing innovations like ICS is the need for a holistic approach. In the case of Inmaculada, the solution was not simply a new admixture or a piece of equipment, but rather the integration of mix design, application method, and mine planning. This required close collaboration between the mine’s geotechnical and operations teams and the technology provider (i.e., Sika). By understanding the mine’s priorities (e.g. advance rate, cost control) and geotechnical constraints (weak rock requiring immediate support, target re-entry strength), the Sika team was able to tailor a combination of products that worked in concert. For example, the compatibility between the superplasticizer and accelerator was critical: if these admixtures had counteracted each other, the result could have been flash setting or inadequate strength gain, leading to downstream issues like clogged equipment or weak shotcrete that might fail during the next blast. Likewise, adding fibers in the mix eliminated the need to install steel mesh for surface control, which not only saved time but also avoided the risk of mesh interfering with the shotcrete spraying or blasting process (loose mesh can be hazardous during mucking and drilling). The holistic approach ensured that each component of the support system complemented the others. This case validates the concept that a mining supplier can act as a holistic partner rather than a mere materials supplier, by delivering a fullpackage solution (materials, engineering know-how, training, and monitoring), the implementation of new technology is smoother and more effective. The authors’ experience during this project was that being involved from the problem identification stage (e.g., participating in the mine’s innovation committee meetings) through to trial execution allowed the team to preempt many potential implementation problems. It also built trust that the solution was genuinely addressing the mine’s needs, not just showcasing a product (Trinh and Macedo, 2020).
RkJQdWJsaXNoZXIy MTM0Mzk2