UPDATE 1-U.S. Mint American Eagle gold, silver coin sales drop in August

(Adds background throughout, U.S. Mint data) NEW YORK, Aug 31 (Reuters) - U.S. Mint sales of American Eagle gold coins fell 40 percent in August from July's highest level in more than two years as concern about a slowing Chinese economy lifted bullion prices above a 5-1/2-year low, government data showed on Monday. American Eagle gold coin sales fell to 101,500 ounces, but that was still four times the sales in August 2014. Sales of American Eagle silver coins also fell in August,