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: Hardenable foam compositions comprising oxygen-releasing foaming agents, a hardener consisting of an alkali silicate solution, a fine particle solid material which reacts with said hardener, namely an oxide mixture consisting of SiO.sub.2 and Al.sub.2 O.sub.3 extracted from a filter dust, an electrofilter ash from high-temperature power plants, and calcinated bauxite or amorphous silica, to which reaction accelerators are added, are improved, firmer, faster hardening foams. Reducing agents, in particular sulphur compounds with a reducing action are preferred. Oxidizing agents or fine particle substances such as soot or color pigments are effective.

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).

Abstract: The present invention is directed to a process for strengthening geological formations in underground mining or other operations introducing into the formation which is to be strengthened mixtures of a polyisocyanate component (a) and a polyol component (b) which react together to form polyurethanes, characterized in that the polyol component (b) is based on mixtures of (i) organic polyhydroxyl compounds having hydroxyl numbers of about 100 to 600 and (ii) dihydric alcohols having a molecular weight of 62 to about 150, component (ii) being present in an amount of about 0.01 to 20% by weight, based on the total quantity of component (b).

Abstract: The present invention is directed to a process for strengthening and sealing geological formations which are moist or contain water, in particular loose stone, by the injection of a mixture which reacts to form polyurethane, characterized in that a polyisocyanate component is injected before injection of the reaction mixture.

Abstract: The manufacture of extended, inaccessible holes for underground ducts, conduits and the like is performed by a closed construction process, wherein the preferably remotely-controlled excavation is performed and following that a structure is installed which is employed as the product duct, conduit or the like. The installed structure is provided by injection of an injection material under pressure into an annular space between a form following the excavating apparatus and the ground to manufacture at least one endless inner wall for the hole which then serves as the underground duct, conduit or the like. The novel apparatus of this invention correspondingly comprises a form following the required excavation mechanism conformed to form an annular space between the form and the ground, that form having a form front closing the form and at least one inlet therein for injection of an injection material into the annular space.

Abstract: Method for bonding of anchoring bolts in boreholes, in which an anchoring bolt is pushed with a rotary motion into a twin-chamber cartridge, one compartment of which is filled with a polyisocyanate component and the other one with a hydroxyl component, prepolymer from the conversion of polyisocyanates with one or several difunctional polyols of the molecular weight range 800-5000, preferably 1600-3000, being used as polyisocyanate component.

Abstract: Coating of geological formations as well as air- and fire barriers is performed by providing aqueous rubber or rubber-like dispersions and spraying the dispersions via separate conduits simultaneously with a dry hydraulic binding medium, by a pressure air onto an object to be coated. An inert filling material can be added to the hydraulic binding medium, and a tenside can be added to the dispersions.

Abstract: A procedure of bonding roofbolt rods to boltholes whereby the roofbolt rod is pushed under rotating movements into a bolthole filled with an adhesive mass consisting of a mix by whose reaction is obtained polyurethane, characterized in that a mass consisting of polyisocyanate-prepolymerides is used which has been prepared from polyisocynates and one or more bifunctional polyols in a molecular weight range between 800 and 5,000, preferably between 1,200 and 3,000, and which reacts in the borehole with 1 to 25% by weight (related to the mass) of water and/or polyols serving as the hydroxyl component.

Abstract: For consolidation of geological formations and artificial beds of rock, earth, and coal by means of foaming and hardening polyisocyanate/polyol blends, diols with secondary hydroxyl functions of the OH number range 150-1000 are used as diol component. Preferably a crude polyisocyanate blend (MDI) obtained by phosgenation of aniline/formaldehyde condensates which at ambient temperature assumes a liquid state, and the liquid prepolymers of said crude MDI are used as isocyanate components.