(19)

(11)

EP 0 463 040 A1

(12)

(43) Date of publication: 02.01.1992 Bulletin 1992/01 (21) Application number: 90904725.0 (22) Date of filing: 16.03.1990

(51) International Patent Classification (IPC):  E01C 23/ 06( . ) (86) International application number: PCT/AU1990/000109 (87) International publication number: WO 1990/010752 (20.09.1990 Gazette 1990/22)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB IT LI LU NL SE (30) Priority: 16.03.1989 AU 19890003256 (71) Applicant: BP AUSTRALIA LIMITED Melbourne Victoria 3000 (AU)	(72) Inventor: HALL, Kenneth, Douglas Dandenong, VIC 3175 (AU) (74) Representative: Hoeger, Stellrecht & Partner  Uhlandstrasse 14 c D-70182 Stuttgart D-70182 Stuttgart (DE)