Abstract: A method is described, using a polyurethane resin mixture, for sealing off points through which water enters geological rock formations. The method utilizes an isocyanate component (a) and a polyol component (b), to be intimately mixed in a static mixer. The mixture is introduced under pressure into the rock formation through boreholes or injection lances. Primary or secondary di or polyamines are substituted for a portion of the polyol component (b) in quantities such that the polyol remains in excess. These amines greatly accelerate the gelation time for the resin, resulting in an instantaneous increase in viscosity of the gel.

Abstract: The present invention relates to a process for strengthening geological formations in underground mining or underground construction work by the introduction of reaction mixtures which react to form polyurethane plastics into the formations which are required to be strengthened, wherein the reaction mixtures are based on(a) a polyisocyanate component,(b) a polyol component and(c) at least one auxiliary agent or additive, characterized in that component (c) contains a cyclic polydimethylsiloxane in the molecular weight range of 222 to 740 and in a quantity of about 0.01 to 5.0% by weight, based on the total weight of components (a) and (b).

Abstract: The present invention is directed to a process for the strengthening of geological formations in underground workings and mines by the introduction of reaction mixtures which react to form polyurethanes into the formations which are to be strengthened, the reaction mixtures being based on(a) a polyisocyanate component,(b) a polyol component and(c) an ester,the ester having a hydroxyl number of about 10 to 630 and an acid number of at most 10 and obtained from (i) an acid component having a carboxyl functionality of at least 1.5 and containing a polymerized fatty acid having at least 12 carbon atoms or mixtures thereof with unpolymerized saturated or unsaturated fatty acids having at least 12 carbon atoms and (ii) a polyol component containing at least one polyhydric alcohol, the ester being present in a positive amount of up to 5% by weight, based on the weight of component (b).