(19)

(11)

EP 2 496 773 A1

(12)

(43) Date of publication: 12.09.2012 Bulletin 2012/37 (21) Application number: 10827708.8 (22) Date of filing: 04.11.2010

(51) International Patent Classification (IPC):  E02D 17/18(2006.01) E21C 41/26(2006.01) E02D 17/20(2006.01) (86) International application number: PCT/AU2010/001459 (87) International publication number: WO 2011/054035 (12.05.2011 Gazette 2011/19)

(84) Designated Contracting States: AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR (30) Priority: 04.11.2009 AU 2009905382 (71) Applicant: BHP Billiton SSM Development Pty Ltd Perth, WA 6000 (AU)	(72) Inventor: HAILE, Andrew Marmion Western Australia 6020 (AU) (74) Representative: Moy, David  Appleyard Lees 15 Clare Road Halifax HX1 2HY Halifax HX1 2HY (GB)