▁Ins lee , ▁were ▁present ▁for ▁the ▁machine ' s ▁dedic ation ▁a ▁week ▁prior ▁to ▁the ▁beginning ▁of ▁exc av ation . ▁ ▁Dam age ▁to ▁cut ter head ▁and ▁two - year ▁delay ▁ ▁By ▁December ▁ 6 , ▁ 2 0 1 3 , ▁Ber tha ▁had ▁tun ne led ▁, ▁or ▁ 1 1 %, ▁of ▁the ▁total ▁ ▁length ▁of ▁the ▁tunnel , ▁stopping ▁about ▁ ▁below ▁ground ▁between ▁South ▁Jackson ▁Street ▁and ▁South ▁Main ▁Street . ▁The ▁machine ' s ▁progress ▁was ▁halt ed ▁on ▁that ▁day ▁by ▁an ▁unexpected ▁imped iment . ▁After ▁a ▁month ' s ▁investigation , ▁W SD OT ▁announced ▁that ▁the ▁machine ' s ▁cutting ▁bl ades ▁had ▁encountered ▁an ▁, ▁ ▁steel ▁pipe , ▁one ▁of ▁several ▁well ▁cas ings ▁left ▁over ▁from ▁a ▁previous ▁ 2 0 0 2 ▁dr illing ▁project ▁that ▁had ▁ass essed ▁ground water ▁conditions ▁and ▁soil ▁stability ▁in ▁the ▁area ▁in ▁case ▁of ▁another ▁earth qu ake , ▁such ▁as ▁the ▁ 2 0 0 1 ▁N is qu ally ▁earth qu ake , ▁which ▁led ▁to ▁a ▁need ▁for ▁the ▁replacing ▁of ▁the ▁Al ask an ▁Way ▁Vi ad uct ▁in ▁the ▁first ▁place . ▁Because ▁the ▁machine ▁cannot ▁cut ▁through ▁metal , ▁the ▁pipe ▁dam aged ▁several ▁of ▁Ber tha ' s ▁cutting ▁bl ades , ▁necess it ating ▁bla de ▁replacement ▁before ▁the ▁machine ▁could ▁proceed . ▁The ▁pip es ' ▁locations ▁were ▁known ▁to ▁W SD OT ▁and ▁the ▁ag ency