| 摘要 |
A drilling equipment device (2') for use when reaming a pilot hole (13) in a rock formation (1), in which a drilling unit (2) comprises a rotatable drill-bit structure (15) fitted with roller cutters (12) which are arranged to break up the rock formation (1), the drill-bit structure (15) and an associated housing (16) being supported on a drill stem (21) which is connected in a rotationally rigid manner to a non-rotatable drill string (4). A method of reaming a pilot hole (13) in a rock formation (1) is described as well. |
