(19)

(11)

EP 2 257 687 A1

(12)

(43) Date of publication: 08.12.2010 Bulletin 2010/49 (21) Application number: 08736810.6 (22) Date of filing: 03.04.2008

(51) International Patent Classification (IPC):  E21B 19/24(2006.01) E21C 25/58(2006.01) E21B 7/28(2006.01) (86) International application number: PCT/FI2008/050161 (87) International publication number: WO 2009/122001 (08.10.2009 Gazette 2009/41)

(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 (71) Applicant: Sandvik Mining and Construction Oy 33330 Tampere (FI)	(72) Inventor: MÄNTTÄRI, Maunu 33330 Tampere (FI) (74) Representative: Kuosmanen, Timo  Kolster Oy Ab P.O. Box 148 Iso Roobertinkatu 23 00121 Helsinki 00121 Helsinki (FI)