(19)

(11)

EP 1 192 299 A1

(12)

(43) Date of publication: 03.04.2002 Bulletin 2002/14 (21) Application number: 00931470.9 (22) Date of filing: 24.05.2000

(51) International Patent Classification (IPC)7: C30B 31/22, C30B 33/00, C30B 29/04, C30B 29/36, C30B 29/40 (86) International application number: PCT/IB0000/694 (87) International publication number: WO 0073/543 (07.12.2000 Gazette 2000/49)

(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: 31.05.1999 ZA 9903665 (71) Applicant: DE BEERS INDUSTRIAL DIAMOND DIVISION (PROPRIETARY) LIMITED Johannesburg 2001 (ZA)	(72) Inventor: PRINS, Johan, Frans 2195 Northcliff (ZA) (74) Representative: Benson, John Everett  J. A. Kemp & Co.,14 South Square,Gray's Inn London WC1R 5JJ London WC1R 5JJ (GB)