Abstract: A device for cutting trenches in hard rock. A plurality of disc-like primary cutters are positioned on arms around a frame. The frame rotates about a central shaft and the center shaft is moved along horizontally in the direction the trench is to be cut. Between the primary cutters are reaming cutters. Each primary and each reaming cutter is provided with a plurality of spaced apart indentors secured to the external surface and each indentor has an end point and being adaptable to penetrate the rock face upon the application of working force a distance "P" and wherein the indentor end points are spaced a distance not greater then 7P apart.

Abstract: The method of implanting a geophone in the earth including the steps of drilling a borehole in the earth, pumping grout into the borehole, pumping a geophone down the interior of a cylindrical pipe positioned in the borehole, the end of the pipe being adjacent the desired point of implantation of the geophone, and pumping additional grout into the borehole to completely surround the geophone and allow the grout to solidify. In one embodiment, a tubular drill pipe having a severable drill bit at the lower end is first used to drill a borehole, after which the drill bit is hydraulically severed from the tubular drill pipe and the grout and the geophone are pumped down into the hole through the interior of the drill pipe.

Abstract: A drilling member for use in a drilling system, such as for drilling a large diameter subterranean hole or for removing rock at the earth's surface, in which the system employs a cutting head rotated about an axis and mounted for movement into a rock face, the cutting head having a plurality of drilling members, each of which has a truncated conical external surface rotated about the conical axis thereof, and a plurality of spaced-apart rows of indentors secured to the drilling member conical surface, the indentors being adapted to penetrate into the rock face a distance P, and wherein the indentors are spaced a distance not greater than 7 P apart.