(19)

(11)

EP 1 183 424 A1

(12)

(43) Date of publication: 06.03.2002 Bulletin 2002/10 (21) Application number: 00937055.2 (22) Date of filing: 06.06.2000

(51) International Patent Classification (IPC)7: E01B 7/02 (86) International application number: PCT/GB0002/190 (87) International publication number: WO 0075/429 (14.12.2000 Gazette 2000/50)

(84) Designated Contracting States: AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT Designated Extension States: AL LT LV MK RO SI (30) Priority: 07.06.1999 GB 9913211 (71) Applicant: Balfour Beatty PLC London EC1V 1SX (GB)	(72) Inventor: TUNLEY, Malcolm Derby DE1 2SA (GB) (74) Representative: Ertl, Nicholas Justin  Elkington and Fife, Prospect House, 8 Pembroke Road Sevenoaks, Kent TN13 1XR Sevenoaks, Kent TN13 1XR (GB)