Abstract: According to a first aspect of the invention there is provided a cutter head arrangement comprising a cutter head portion including a (substantially cylindrical) cutter head side wall to define a chamber (or cavity) surrounded by the cutter head side wall. A substantially circular rim portion extends from (a distal end of) the cutter head side wall, the rim portion defining a working, contact face of the cutter head portion. A recessed wall portion extends away from the rim portion inwardly into the chamber so as to be surrounded by the cutter head side wall, with the rim portion and/or the recessed wall portion being fitted with a plurality of cutter elements, to enable the cutter head portion to blind bore a pilot hole in use. The recessed wall portion that extends away from the rim portion inwardly into the chamber is a substantially conical body so as to define a conical recess (proximate a central region of the cutter head portion, at a distal end of the cutter head portion).

Abstract: A shaft enlargement arrangement for a boring system comprises a hollow column proximate a lower end of the boring system. A reamer section comprising a downwardly tapering first cutter head arrangement is rotatably fitted to the hollow column, with a first drive being provided to rotate the first cutter head arrangement relative to the hollow column so as to bore downwardly a hole having a diameter corresponding substantially to the diameter of the first cutter head arrangement. A boring head arrangement is fitted to an operatively lower end, the boring head arrangement terminating in a downwardly tapering second cutter head arrangement to bore a leading or pilot hole, having a diameter that is less than the diameter of the first cutter head arrangement, as the boring system proceeds to bore downwardly.

Abstract: A shaft enlargement arrangement for a boring system is provided, the shaft enlargement arrangement comprising a hollow column proximate a lower end of the boring system; a first cutter head that is rotatably fitted to the hollow column, with first drive means being provided to rotate the first cutter head relative to the hollow column so as to bore downwardly a hole having a diameter corresponding substantially to the diameter of the first cutter head; and a boring head arrangement fitted to an operatively lower end of the column, the boring head arrangement terminating in a second cutter head to bore a leading hole as the boring system proceeds to bore downwardly. In an embodiment, the first cutter head comprises a support body carrying a winged arrangement, the support body being rotatably fitted to the column, the winged arrangement comprising a plurality of wings extending from the support body, each wing being fitted with, or comprising, a plurality of first cutter elements.