(19)

(11)

EP 2 220 336 A1

(12)

(43) Date of publication: 25.08.2010 Bulletin 2010/34 (21) Application number: 08861896.2 (22) Date of filing: 15.12.2008

(51) International Patent Classification (IPC):  E21B 21/08(2006.01) E21B 44/00(2006.01) E21B 7/02(2006.01) (86) International application number: PCT/FI2008/050742 (87) International publication number: WO 2009/077656 (25.06.2009 Gazette 2009/26)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MT NL NO PL PT RO SE SI SK TR Designated Extension States: AL BA MK RS (30) Priority: 17.12.2007 FI 20075923 (71) Applicant: Sandvik Mining and Construction Oy 33330 Tampere (FI)	(72) Inventors: SORMUNEN, Tapani FI-33610 Tampere (FI) JUUJÄRVI, Kari FI-37130 Nokia (FI) (74) Representative: Kuosmanen, Timo  Kolster Oy Ab P.O. Box 148 Iso Roobertinkatu 23 00121 Helsinki 00121 Helsinki (FI)