OPERATOR LOST CONTROL OF LOADER ROLLED IT ABOUT 180 DEGREES,T HE OPERATOR WAS BUILDING BERMS ON A ROAD GOING INTO THE PIT THE ROAD WAS 20' WIDE WITH 17% GRADE AND 13% CROSS SLOPE. AT THE TIME THE OPERATOR WAS TRAVLING IN 3RD GEAR WITH A LOADED BUCKET EXTENDED OUT MID LEVEL OPERAOR TURNED SHARPLY TO DUMB THE LOAD AND THE LOADER ROLLED 180 DEGREES.