Complex sentence: The construction work involved approximately 2,500 thousand people, required more than 10 thousand cubic metres of masonries and approximately 6,5 tons of iron, and what is more, Belelyubsky personally obtained iron from Belgium, demanding to improve its quality.
Split into simpler sentences: The construction work involved approximately 2,500 thousand people, required more than 10 thousand cubic metres of masonries and approximately 6,5 tons of iron. What is more, Belelyubsky personally obtained iron from Belgium, demanding to improve its quality.