(19)

(11)

EP 0 819 208 A1

(12)

(43) Date of publication: 21.01.1998 Bulletin 1998/04 (21) Application number: 96909909.0 (22) Date of filing: 03.04.1996

(51) International Patent Classification (IPC):  E21C 35/ 19( . ) E21C 35/ 18( . ) E21C 35/ 197( . ) (86) International application number: PCT/US1996/004532 (87) International publication number: WO 1996/031682 (10.10.1996 Gazette 1996/45)

(84) Designated Contracting States: DE FR GB SE (30) Priority: 06.04.1995 ZA 19950002855 (71) Applicant: KENNAMETAL SOUTH AFRICA (PROPRIETARY) LIMITED Boksburg 1459 l (ZA)	(72) Inventors: WRIGHT, Noel, G. The Reeds 0158 (ZA) HOLTSHAUSEN, Richard, George Lynnwood Glen 0081 (ZA) (74) Representative: Baillie, Iain Cameron, et al  c/o Ladas & Parry Altheimer Eck 2 80331 München 80331 München (DE)