(19)

(11)

EP 0 463 049 A1

(12)

(43) Date of publication: 02.01.1992 Bulletin 1992/01 (21) Application number: 90904883.0 (22) Date of filing: 16.03.1990

(51) International Patent Classification (IPC):  B01J 8/ 18( . ) C01B 31/ 36( . ) C01F 7/ 02( . ) B01J 19/ 08( . ) C01B 33/ 18( . ) C01F 7/ 30( . ) (86) International application number: PCT/GB1990/000394 (87) International publication number: WO 1990/010496 (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 GB 19890006045 (71) Applicant: DAVY RESEARCH AND DEVELOPMENT LIMITED Stockton-on-Tees, Cleveland TS18 3HA (GB)	(72) Inventors: NADEN, David 47 Scalby Grove Cleveland TS19 7RP (GB) BAGHA, Shahin Cleveland TS23 3SX (GB) (74) Representative: Eyles, Christopher Thomas, et al  W.P. THOMPSON & CO. Celcon House 289-293 High Holborn London WC1V 7HU London WC1V 7HU (GB)