114 block remained stable during the subsequent long hole blasting and extraction. The mine successfully recovered 100% of the ore in this block in a single continuous stope, with no unplanned dilution or ground falls. In addition to the safety achievement (no collapses or injuries), the economic benefit was significant: an estimated 15–20% increase in recoverable ore from that section, translating to millions in additional revenue that would have been forfeited if the block were lost. This case has become a benchmark within the company for how intelligent injection design can enable safe mining of challenging reserves. Consolidation of backfill for pillar mining: at the Toguraci gold mine in Indonesia, a novel application of grout injection was used to improve the stability of unconsolidated rockfill (URF) in historic stopes, allowing the extraction of underlying sill pillars that were previously deemed risky. The approach involved drilling injection holes into the old backfilled stopes from levels above and pumping a cementitious grout at a controlled water: cement ratio throughout the fill mass (Proudman et al., 2017). Over a series of stages, the fractured rockfill material was turned into a more competent, concrete-like body (with an average uniaxial compressive strength ~8 MPa achieved in the fill). Result: The cemented fill was able to temporarily support itself as the sill pillars beneath were blasted and extracted. No fill collapse occurred during pillar recovery, and only minimal dilution was recorded in the ore, validating the effectiveness of the pre-consolidation. This project demonstrated that even loose waste materials can be converted into stable engineered support via injection, expanding the possibilities for mining sequences (e.g., pillar recovery or mining beneath backfilled areas) that otherwise would be off-limits. Enhanced longwall entry stability in weak roof: in a North American coal mine, longterm development entries for a future longwall were experiencing severe roof degradation due to a combination of closely spaced joints and water seepage along bedding planes. Despite dense bolting patterns and steel meshing, the roof rock between bolts was delaminating and collapsing, threatening the viability of the entries. A targeted chemical injection program was implemented, using polyurethane grout injected through holes drilled upward beyond the bolted horizon (Hildreth et al., 2020). The objective was to fill the voids and seal the water pathways in the otherwise unconfined roof layers. Result: The injection effectively pushed water away from the immediate roof (redirecting it to areas where it could be drained without damaging support) and bonded the fragmented roof laminations together. Subsequent monitoring showed a dramatic decrease in roof deformation and closure rates. The treated entries remained stable and serviceable through the longwall retreat, whereas comparable areas without injection had required constant maintenance and still showed significant deterioration. This result underscores that in weak, moisture-sensitive ground, injections can augment conventional supports by creating a continuous internally reinforced zone that bolts and beams can then securely hold. Collectively, these results demonstrate that injection and consolidation measures can resolve critical issues that might otherwise impede mining. Key performance indicators across these cases include water inflow reduction, ground deformation reduction, increased extraction of ore (reduced ore loss or dilution), and improved safety (fewer falls of ground and less emergency interventions). Moreover, a common outcome is that mines gain operational
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