Abstract: The invention provides an excavation bit (10) which is constructed from either a single or double carrier. If two carriers (14 and 15) are present, the carriers (14, 15) are contra-rotating. By the off setting of the axes of rotation (17 and 18) of single or dual carriers from a longitudinal axis (22) of the bit (10) and by driving the carriers to rotate, a ground engaging thrust is produced, as well as the rotation of the excavation bit (10) in the ground as a consequence of the rotation of the carriers, and not vice versa as in the case with prior art. By the invention, there can result sufficient thrust on the bit (10) by the rotation of the carriers (14 and 15) so that the need to apply thrust down the bore via the drill rod is reduced or eliminated. As a result of the invention, the number and/or size of the ground engaging tools (25) are not a function of the bore diameter to be drilled.