* China says at least 8,600 dead but it expects figure to rise. * 900 children also buried when a school building collapsed, 50 bodies found. * The 7.9-magnitude quake's epicenter was Wenchuan county in Sichuan Province which has a population of about 112,000. * An earthquake with 7.5 magnitude in the northern Chinese city of Tangshan killed 255,000 people in 1976 -- the greatest death toll ...


