Abstract: A mobile tunnel boring unit is disclosed, comprising a support body driven by first drive means, the first drive means including a pair of spaced apart crawler tracks in contact with the tunnel floor and related track driving means to move the tracks. A cutter head drive means is located at an operatively front end of the boring unit, to which a rotatable cutter head can be fitted and rotatingly driven, in use, the cutter head comprising a full face cutter head fitted with cutters to bore a tunnel face. The cutter head is arranged to allow cuttings to pass through the cutter head for discharge into a muck hopper and onto a first conveyor arrangement, the cutter head drive means and a rear portion of the cutter head defining aligned central apertures to accommodate the muck hopper and a front part of the first conveyor arrangement. A telescopic shield arrangement is provided to shield the boring unit.

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 reamer section comprising a downwardly tapering first cutter head arrangement is rotatably fitted to the hollow column, with first drive means 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.