While operating a 631, # 12 scraper, EE was loaded and headed to the fill. As he came out of the 8 ditch onto level ground, he lost control of the scraper and ran over a windrow on the left side of the road. After traveling about 20 yards, EE got control and crossed the windrow back onto the road to his right and pulled the scraper off the road to the right side of the road.