(19)

(11)

EP 0 413 696 A1

(12)

(43) Date of publication: 27.02.1991 Bulletin 1991/09 (21) Application number: 89903195.0 (22) Date of filing: 03.02.1989

(51) International Patent Classification (IPC):  E02D 1/ 02( . ) G01N 3/ 30( . ) G01M 7/ 08( . ) (86) International application number: PCT/GB1989/000098 (87) International publication number: WO 1989/007176 (10.08.1989 Gazette 1989/18)

(84) Designated Contracting States: DE FR GB IT (30) Priority: 05.02.1988 GB 19880002626 (71) Applicant: GEOTECHNICS LTD. Coventry CV6 5SF (GB)	(72) Inventors: COBBE, Michael, Ian Northampton NN6 8EJ (GB) THREADGOLD, Leonard Warwickshire CV32 6PW (GB) (74) Representative: Gibson, Stewart Harry, et al  URQUHART-DYKES & LORD, Three Trinity Court, 21-27 Newport Road Cardiff CF2 1AA Cardiff CF2 1AA (GB)