116 longwall entry example (Hildreth et al., 2020), the injection was carried out as a separate shift in the cycle of tunnel support, with pre-drilled holes ready so that chemical grout could be pumped in with minimal delay to the development schedule. Such planning requires experience and flexibility. 4.3 Combined support systems: an overarching theme is that injection is most effective when used in combination with conventional ground support. Rather than replacing bolts, shotcrete, or steel supports, injections augment them. By consolidating the ground, injections provide a firm substrate for shotcrete to bond or for bolts to anchor. Conversely, shotcrete can be used to seal exposed surfaces and contain grout during injection (as noted in the rockfill consolidation case, where a skim coat of shotcrete helped prevent grout from leaking out of filled voids (Proudman et al., 2017). Modern mining practice thus views injection as one component of an integrated ground support system. For example, a standard integrated approach for a wet, weak ground drive might be: (1) pre-grout ahead of the face to reduce water and stabilize, (2) excavate and install rock bolts and mesh, (3) immediately spray fiber-reinforced shotcrete for surface support, and (4) if monitoring shows areas of persistent movement or leakage, do postinjection through drilled holes in the affected zones to stiffen them. By designing these elements together, the overall support achieves what none of them could alone: shotcrete and bolts secure the surface and hold strong blocks, while injections solidify the weak internals and stop water that would otherwise defeat the other supports. Sika’s capability to supply complementary technologies – not just injection resins and grouts, but also shotcrete admixtures, fibers, and rock bolt grouting materials – means the solutions are synergistic. The company often deploys a multi-disciplinary team (geotechnical engineers, concrete specialists, mining engineers) to a project, ensuring that each aspect of ground control is addressed in a compatible way. 4.4 Economic and safety implications: an important discussion point is the cost-benefit aspect of injection in mining. At first glance, injection works add cost and complexity to a project; for example, specialized materials like resins can be more expensive per volume than ordinary shotcrete. However, the return on investment for injections is often extremely high when considering the value of ore recovered and the prevention of delays or accidents. In the case of the consolidated ore block (Ferrenbach, 2025), the cost of the resin and drilling was a small fraction of the value of the ore that was safely extracted as a result. Similarly, preventing a major water inrush or stope collapse not only avoids direct losses but preserves the mine’s operational continuity and safety record. There is also a sustainability angle: effective water sealing can reduce the need for perpetual pumping (saving energy and discharge treatment), and stabilizing ground can reduce waste by allowing more complete ore extraction from a given footprint. Therefore, when mines evaluate risk mitigation strategies, injection should be considered alongside traditional methods, and its benefits quantified in terms of risk reduction. By framing injections in terms of risk management and value creation rather than as a sunk cost, mine management can make informed decisions to deploy these technologies where they make the most impact.
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