Dual purpose drill rig

Claim 1

41,072/72 The claims defining the invention are as follows:- 1. A drill rig comprising a base frame, a diamond "404 4WAMIM dWI drill head carried by the base frame, and a mas -ext--eng upwardly from the diamond drill head and to one side thereof, said diamond drill head comprising a hollow mandrel, chuck assembly and drive means for rotating said mandrel; guide means on the mast, a saddle, guide engaging means on the saddle engaging said guide means, power means operatively coupling the mast and the saddle for effecting movement of the saddle along the guide means towards or away from the diamond drill head, and an air operated drill head on the saddle having its axis coaxial with the axis of the hollow mandrel and chuck assembly, so constructed and arranged that an air operated drill rod secured for drive to the air operated drill head extends through and is guided by said hollow mandrel and chuck assembly. 2. A drill rig according to claim 1 comprising pivot means joining the mast and base frame, said pivot means having a substantially horizontal axis when the mast is erect. 3. A drill rig according to either claim 1 or claim 2 wherein said saddle is a front saddle and guide means on the mast comprise four parallel channel section members arranged in two pairs, one behind the other, the front of the two pairs being engaged by said guide engaging means on the front saddle and the rear of the two pairs being engaged by guide engaging means on a rear saddle, said power means comprising an hydraulic ram operatively 460.673 4107 2 /72 connected between the mast and said rear saddle for moving said rear saddle along the guide means, and means coupling said rear saddle to said front saddle whereby the hydraulic ram in turn effects said movement of said front saddle along its guide means. 4. A drill rig according to Claim 3 wherein said means coupling said4Lpeke to said front saddle comprise a cable, means securing the ends of the cable to the mast, and pulleys on both the mast and the pulley plate guiding the cable, the cable being connected to the front saddle intermediate its ends and being so arranged that the front saddle moves twice the distance of the rear saddle. A drill rig according toLan-y -preedn- Claim wherein the front saddle comprises a guide engaging portion, a saddle plate, a hinge between the guide engaging portion and the saddle plate hinging the saddle plate relative to the guide engaging portion about an axis which is vertical when the mast is erect, saidrill head being carried on the saddle plate. 6. A drill rig according to Claim 5 wherein the saddle plate comprises a turntable rotatable about an axis which is horizontal when the mast is erect, said airkdrill head being secured to the turntable. 7. A method of,drilling a hole in the ground with a rig which is in accordance with Claim 6, comprising attaching a drill rod to said air drill head, positioning the lower end of the drill rod through said hollow mandrel and chuck assembly, drilling a-hele for a distance less than the 460.673