▁was ▁turned ▁to ▁Pol lt ul ly ard , ▁the ▁down stream ▁end ▁of ▁which ▁lay ▁within ▁ ▁of ▁up stream ▁J CP ▁Pass age , ▁according ▁to ▁the ▁surve ys . ▁Vari ous ▁groups ▁of ▁ca vers ▁attempted ▁to ▁dig ▁through ▁the ▁terminal ▁b ould er ▁cho ke , ▁but ▁none ▁were ▁successful ▁in ▁stabil ising ▁the ▁passage . ▁In ▁ 2 0 0 4 ▁ca vers ▁from ▁the ▁Sh annon ▁Group ▁began ▁in ▁earnest ▁to ▁attempt ▁to ▁re - enter ▁the ▁system , ▁and ▁initi ated ▁a ▁new ▁dig ▁in ▁the ▁direction ▁of ▁Sh annon ▁C ave . ▁By ▁ 2 0 0 5 ▁Sh annon ▁C ave ▁had ▁been ▁re - enter ed ▁via ▁a ▁very ▁tight ▁section ▁of ▁passage ▁named ▁the ▁" R eb irth ▁Canal ". ▁The ▁ca vers ▁had ▁reg ained ▁J CP ▁Pass age , ▁and ▁access ▁to ▁the ▁rest ▁of ▁the ▁cave ▁as ▁far ▁as ▁George ' s ▁Ch oke , ▁which ▁had ▁col lapsed ▁again ▁as ▁reported ▁by ▁ca vers ▁on ▁the ▁last ▁trip ▁into ▁Sh annon ▁C ave . ▁In ▁ 2 0 0 7 , ▁after ▁two ▁years ' ▁work ▁dig ging ▁and ▁stabil ising , ▁George ' s ▁Ch oke ▁was ▁passed . ▁The ▁expl or ers ▁reached ▁the ▁terminal ▁sum p , ▁the ▁first ▁people ▁to ▁do ▁so ▁in ▁twelve ▁years . ▁▁ 2 0 0 8 : ▁Saint ▁Patrick ' s ▁Ext ension ▁ ▁A ▁new ▁dig ▁began ▁on ▁a ▁bal con y ▁above ▁the ▁terminal ▁sum p ,