Abstract: A method of forming a hole in a hard ground structure including the step of obtaining a drill-bit with a turning axis having: a central portion and first and second axially spaced ends; and a plurality of protruding blades. Each blade has first and second ends, a first end portion, a second end portion, a middle portion, and a circumferentially facing leading portion. The circumferentially facing leading portion of each blade has at least one discrete hard cutter thereat. The method further includes the step of turning the drill-bit around its axis in a first direction so that the blades are advanced, circumferentially facing leading portion first, while pulling the drill-bit axially, with the first drill-bit end in a leading direction, through the hard ground structure to thereby cause the discrete cutters to cut the hard ground structure.

Abstract: The present document describes a drill-bit which achieves both the rigidity and a fast rate of penetration. The drill-bit comprises a cone shaped central portion comprising a plurality of ribs protruding from the central portion and defining a plurality of blades. The blades are curved along a direction of a longitudinal axis of the cone to facilitate insertion into a hole when rotating in a first direction, and exit from the hole when rotating in a second direction opposite the first direction. The drill-bit comprises a plurality of polycrystalline diamond cutters (PDC) on the blades provided in a first position for cutting the hard structure as the drilling-bit rotates in the first direction, and a plurality of up-drill PDC cutters provided in a second position for cleaning the hole as the drill-bit rotate in the second direction to exit the hole.

Abstract: The present document describes a drill-bit which achieves both the rigidity and a fast rate of penetration. The drill-bit comprises a cone shaped central portion comprising a plurality of ribs protruding from the central portion and defining a plurality of blades. The blades are curved along a direction of a longitudinal axis of the cone to facilitate insertion into a hole when rotating in a first direction, and exit from the hole when rotating in a second direction opposite the first direction. The drill-bit comprises a plurality of polycrystalline diamond cutters (PDC) on the blades provided in a first position for cutting the hard structure as the drilling-bit rotates in the first direction, and a plurality of up-drill PDC cutters provided in a second position for cleaning the hole as the drill-bit rotate in the second direction to exit the hole.

Abstract: The present document describes a drill-bit which achieves both the rigidity and a fast rate of penetration. The drill-bit comprises a cone shaped central portion comprising a plurality of ribs protruding from the central portion and defining a plurality of blades. The blades are curved along a direction of a longitudinal axis of the cone to facilitate insertion into a hole when rotating in a first direction, and exit from the hole when rotating in a second direction opposite the first direction. The drill-bit comprises a plurality of polycrystalline diamond cutters (PDC) on the blades provided in a first position for cutting the hard structure as the drilling-bit rotates in the first direction, and a plurality of up-drill PDC cutters provided in a second position for cleaning the hole as the drill-bit rotate in the second direction to exit the hole.