Abstract: A sampling drill comprising a plurality of drill rods coupled together to form a drill stem suspended from a drill head, each of the drill rods comprising a pair of substantially concentric tubular members defining an inner central passage and an annular passage, the lower end of the drill stem being fitted with a drill bit having an inner chamber adapted to be connected to the inner central passage of the drill stem, and one or more passages adapted to be connected at one end to the annular passage in the drill stem and at the other end to discharge into the inner chamber, the inner chamber being provided with openings located adjacent the cutting edges of the drill bit so that material cut by the drill bit can pass into the chamber, and means for shutting off the inner central passage to prevent material entering the inner chamber of the drill bit and entering the inner central passage.

Abstract: A core sampling drill comprising a drill bit having a series of cutting surfaces arranged around a central core hole, the upper end of the drill bit being threaded so that it can be fitted to the lower end of a tubular drill stem, a core tube positioned within the lower end of the drill stem substantially concentric therewith and spaced apart therefrom to provide an outer annular passage, the inner portion of the outer wall of the drill bit being provided with an annular recess which is arcuate in cross section so that air flowing downwardly through the outer annular passage is turned through approximately 180.degree. and directed upwardly into the core tube so that the material cut by the drill bit is entrained therein and carried into the core tube.