▁resident ial ▁community ▁that ▁had ▁once ▁occupied ▁the ▁subject ▁site . ▁▁ 2 0 0 6 - 2 0 1 0 ▁ ▁Sydney ▁Har bour ▁For esh ore ▁Author ity ' s ▁panel ▁selected ▁the ▁winning ▁proposal ▁for ▁the ▁site ▁by ▁Youth ▁Host els ▁Australia ▁for ▁a ▁state - of - the - art , ▁energy - efficient ▁host el ▁with ▁an ▁additional ▁tw in ▁class room ▁education ▁centre . ▁Y HA ▁Ltd ▁is ▁a ▁not - for - pro fit ▁organisation ▁that ▁returns ▁prof its ▁from ▁ear nings ▁back ▁into ▁its ▁capital ▁assets . ▁Const ruction ▁of ▁Sydney ▁Har bour ▁Y HA ▁and ▁The ▁Big ▁Dig ▁Arch ae ology ▁Education ▁Centre ▁took ▁place ▁between ▁September ▁ 2 0 0 8 ▁and ▁October ▁ 2 0 0 9 . ▁During ▁construction ▁the ▁arch ae ological ▁rem n ants ▁on ▁site ▁were ▁carefully ▁covered ▁by ▁a ▁protect ive ▁layer ▁of ▁sand b ags ▁and ▁sc aff old ing , ▁removed ▁when ▁the ▁construction ▁work ▁was ▁completed . ▁The ▁buildings ▁are ▁supported ▁by ▁struct ural - ste el ▁tr uss es ▁sp anning ▁over ▁the ▁arch ae ological ▁remains , ▁allowing ▁over ▁ 8 5 % ▁of ▁the ▁site ▁to ▁be ▁visible ▁at ▁ground ▁level . ▁The ▁physical ▁impact ▁on ▁the ▁site ▁is ▁restricted ▁to ▁, ▁in ▁areas ▁carefully ▁chosen ▁in ▁consult ation ▁with ▁the ▁arch ae olog ists . ▁ ▁The ▁ 1 0 6 - room ▁Sydney ▁Har bour ▁Y HA ▁host el ▁and ▁The ▁Big ▁Dig ▁Arch ae ology ▁Education ▁Centre ▁were