Complex sentence: The race is run at a distance of one mile on the dirt at Belmont Park in October each year and is arguably the biggest race of the year in its category--excepting the Breeders' Cup Juvenile for which the Champagne is a major prep.
Split into simpler sentences: The race is run at a distance of one mile on the dirt at Belmont Park in October each year. It is arguably the biggest race of the year in its category, excepting the Breeders' Cup Juvenile for which the Champagne is a major prep.