Aug 07, 2013· CLICK HERE FOR 's UPDATED RANKING OF THE WORLD'S LARGEST GOLD DEPOSITS. The other two mines are Cadia Hill and Ridgeway. Cadia Hill is a large openpit mine nearing the end of its useful life just as the newly developed Cadia East recently began its expected 30 year mine life. Gold was first discovered in the gold and copper bearing Cadia region in 1851 and .