(19)

(11)

EP 1 084 381 A1

(12)

(43) Date of publication: 21.03.2001 Bulletin 2001/12 (21) Application number: 99920995.0 (22) Date of filing: 07.05.1999

(51) International Patent Classification (IPC)7: G01C 15/00, E21D 9/00 (86) International application number: PCT/GB9901/438 (87) International publication number: WO 9957/515 (11.11.1999 Gazette 1999/45)

(84) Designated Contracting States: AT CH DE DK FR GR IT LI SE (30) Priority: 07.05.1998 GB 9809638 (71) Applicant: Tunnel Management Systems Limited Bridgwater,Somerset TA6 4BH (GB)	(72) Inventor: MOSS, Arthur F. Bridgwater,Somerset TA6 4BH (GB) (74) Representative: Brown, Michael Stanley  Alpha and OmegaChine CroftEast Hill Ottery St. MaryDevon EX11 1PJ Ottery St. MaryDevon EX11 1PJ (GB)