The high unit cost of chemical grouts, as compared with clays and cements, requires a different engineering approach to their use in the field. This has resulted in the development of techniques designed to minimize waste of grout and maximize accuracy of placing of grout at desired locations. These techniques require the use of procedures which are often exactly opposite to those used with cements. Since experienced cement grouters are often asked to use the newer chemical grouts, it has been difficult for them to assimilate the required techniques. In particular, the use of gel times shorter than the pumping time has been difficult to accept. In the past decade, however, as field experience has grown, and the mechanism of short gel times studied, acceptance also has grown of all the procedures pertinent to chemical grouting. A rapidly growing core of knowledge is now forming the basis for a new chemical grouting technology.