U.S. markets tank, Mar. 16-20: Sandstorm Gold, Alamos Gold, Rio Tinto

The Dow Jones Industrial Average fell 17.30% (4,011.64 points) to 19,173.98 and the S&P 500 dropped 14.98%(4,061.1 points) to 2,304.92 during the Mar. 16-20 trading…