The drill rod (11) is mounted on an upper support (9) fixed to an intermediate support (8). The intermediate support (8) is mounted on a lower support (1) on the upper end of a swinging telescopic arm (2). The intermediate support (8) can slide relative to the lower support (1) but is so mounted that it does project in either the forward or rearward directions or it projects only very slightly in the forward direction. In addition the upper support (9) slides relative to the intermediate support but does not project in the forward or rearward directions or at least only very slightly in the forward direction. USE/ADVANTAGE - Underground tunnelling. The overall length of the machine is restricted within convenient limits.
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