This underground mine, which is 1,100 feet below the surface, mined into a core hole taken from the surface. The core hole was dumping significant amounts of ground water into the mine. To stop the water inflow, a high-pressure probe and polyurethane grout was implemented. Grouting contractor Sub-Technical, Inc. used their specially designed probe to insert into the core hole. The probe contains a port where polyurethane can then be injected to permanently seal it off. The polyurethane used was SealGuard II, which is manufactured by SealGuard, Inc. SealGuard II is a dual component polyurethane grout that reacts in about 3 seconds to produce a rigid foam. The cured foam has a 900-psi compression strength.