 No explosives are said to be used on the construction of the tunnel.Drilling of the tunnel itself commenced in mid-November 2011, with the drilling machine beginning work on the Watson Island tunnel entrance.The first tunnel connecting Watson Island and the Port of Miami was completed in August 2012., and the second tunnel was completed on May 9, 2013, as "Harriet" emerged back on Watson Island, where digging had commenced in 2011.