Cementous grout can only be delivered at depths below 20′ and polyurethane (foam) can only be delivered up to 7-20′. Our delivery method ensures that we reach the desired depth and does not allow the material to harden before we reach the affected area. This technology can be used not only to fix sinkholes but also fix dams, levees, canals, embankments, landslides, and tunnels with fast-action polyurethanes.