REDPATH MINING – RIO TONTO
Project Scope
Work was executed 800 m from the portal in a 4.7 m diameter tunnel with severe access and operational constraints. Multicrete designed and deployed specialized batching and grouting systems to support continuous underground injection in a confined environment.
A custom grout header system was developed to control injection pressure (limited to 100 psi), monitor flow rates, and ensure compliance with strict refusal criteria. A high-flow groundwater zone (~800 L/min) was treated using a specialized water-stop grout mixed via colloidal system and injected to displace water and consolidate the formation.
Final Product
The grouting program was completed in 3.5 weeks instead of the planned 6 weeks. Post-injection verification confirmed full ground encapsulation, reduced water inflow to ~50 L/min, and elimination of hydrostatic pressure behind the treated zone.
Product Highlights
- Stabilization of critical weak ground zone in Rio Tinto Kemano T2 tunnel
- Underground work executed 800 m from portal in 4.7 m diameter confined tunnel
- Custom-designed grout header system for real-time pressure and flow control
- Strict injection pressure management capped at 100 psi with refusal monitoring
- High water inflow zone (~800 L/min) successfully treated with specialized water-stop grout
- Colloidal mixing system used for consistent grout quality and placement control
- Improved schedule performance, completing grouting in 3.5 weeks vs 6-week plan
- Post-injection verification confirmed full void filling and reduced inflow to ~50 L/min
