▁ ▁Car ▁Im ports ▁ ▁In ▁ 2 0 0 7 , ▁imported ▁car ▁un loading ▁operations ▁were ▁moved ▁from ▁Sydney ▁Har bour ▁to ▁Port ▁K emb la . ▁The ▁first ▁two ▁ 5 5 , 0 0 0 ▁t onne ▁car ▁carri ers ▁comm enced ▁un loading ▁on ▁ 1 0 ▁May ▁ 2 0 0 7 . ▁ ▁Cast ing ▁Bas in ▁ ▁As ▁part ▁of ▁the ▁construction ▁facilities ▁for ▁the ▁Sydney ▁Har bour ▁T unnel ▁( cont ract ▁signed ▁in ▁June ▁ 1 9 8 7 ) ▁a ▁casting ▁bas in — 1 0 0 m ▁wide , ▁ 3 2 0 m ▁long , ▁and ▁overall ▁ 1 2 . 5 m ▁deep — was ▁exc av ated ▁in ▁the ▁western ▁section ▁of ▁the ▁Inner ▁Har bour . ▁The ▁sub mer ged ▁sections ▁of ▁the ▁tunnel — each ▁we igh ing ▁ 3 0 , 0 0 0 ▁tons — w ere ▁built ▁there , ▁tempor arily ▁se aled , ▁flo ated ▁and ▁to wed ▁to ▁Sydney ▁for ▁installation . ▁After wards , ▁the ▁casting ▁bas in ▁was ▁used ▁to ▁make ▁huge ▁concrete ▁gravity - based ▁structures ▁for ▁two ▁off - sh ore ▁oil ▁platforms , ▁from ▁ 1 9 9 3 ▁to ▁ 1 9 9 6 . ▁ ▁See ▁also ▁▁▁ ▁Coast al ▁coal - car ry ing ▁trade ▁of ▁New ▁South ▁Wales ▁ ▁References ▁ ▁External ▁links ▁ ▁Port ▁K emb la ▁Har bour ▁Environment ▁Group ▁Il la war ra ▁Heritage ▁Tra il ▁- ▁Port ▁K