Various
1988 - 1998
ECO has designed and supervised the construction of several mine plugs and permanent flood bulkheads. The plugs have been used to seal underground works after the ore has been depleted or to seal off areas of a mine where the water inflow impaired the operation of another part of the mine. Plugs (or bulkheads) are designed to be water tight and have a long life expectancy.
Special techniques that were designed and supervised by ECO were:
- Bentonite/sand seals upstream of the plug.
- “Stabilized” (delayed and slow curing) concrete bulkheads
- Formation grouting reducing permeability to less than 0.1 Lu via pre-drilled holes.
- Contact grouting via pre-placed injectable tubes.
- Backfill grouting via pre-placed flexible sleeve pipes.
- Multiple hole grouting systems to save the client as much as 50% of routine grouting operation costs ending up with a lower residual permeability.
The combination of the massive plug, bentonite/sand seal and the grouting program reduced the water flow in the area of the plug to less than 0.1 Lugeon