Preparations for the massive operation to slide a 19,000-ton roof into position over the main Athens Olympic stadium have started, the government said over the weekend, while the entire process should be finished in late May. Progress on the 80-meter-high steel-and-glass structure designed by Spanish architect Santiago Calatrava has been one of the main headaches for the International Olympic Committee, which fears delays with the mainly decorative roof will endanger more important work on the stadium. On Saturday, Deputy Culture Minister for Olympic preparations Fanni Palli-Petralia denied any delay in the 130-million-euro project. «The process for the sliding has started,» she said. «We will wake up one morning and find [the roof] in position.» In an interview in the Sunday Eleftheros Typos, Petralia said the process should be finished by the end of May. «In that case, we will be able to say with certainty that no alternative plan is necessary, although to be quite honest I have asked for one to be drafted,» she said.