BAT Construction was engaged to complete a complex underground contact grouting and system decommissioning program at the Bennett Dam hydroelectric facility. After BAT Construction completed the installation of rockfall canopies in the Fall of 2024, so that the crew could safely enter the tunnels, the project focused on permanently sealing and decommissioning critical underground systems while maintaining safe operations within an active underground environment. The work was completed with zero safety incidents, zero environmental impact, and ahead of schedule.
Project Scope
BAT Construction performed extensive underground cleaning, inspection, and contact grouting across multiple Low Level Outlet (LLO) chambers and associated infrastructure.
Scope of work included:
- Cleaning and inspection of LLO chambers (Low Level Outlets are control systems that manage water discharge at low reservoir levels)
- Preparation and grouting of:
- Bonnets (Protective housings over valves)
- HPUs (Hydraulic Power Units that operate gates and valves)
- Electrical conduits (Protective pathways for electrical cables)
- Blowdown lines and vent lines (Piping systems used to release pressure or drain water)
- Associated underground infrastructure
- Drilling, installing, and grouting rock dowels in tunnels
All work was executed to achieve permanent sealing, long-term system decommissioning, and environmental protection, eliminating any potential for future water discharge.
Project Challenges
This project was executed within a live underground hydroelectric facility, requiring exceptional safety discipline, coordination, and technical precision.
Key challenges included
- Restricted access and confined underground work areas (Confined spaces require special safety procedures due to limited entry and exit)
- Stringent safety requirements for underground and confined-space operation
- Extremely high cleanliness and inspection standards prior to grouting (Surfaces must be completely clean to ensure grout bonds properly)
- Multiple inspection hold points and evolving approval requirements
- Coordination with multiple stakeholders and concurrent contractors working within the facility
Through detailed planning, adaptive execution, and a safety-driven approach, BAT Construction successfully navigated these challenges without compromising quality, safety, or schedule.
