Sinkholes are fairly common, due to collapsed caves, old mines or dissolving material, but the circumstances in South Dakota ...
Michigan trailed 24-20 when it got the ball back at its own 11 with four minutes left and put together a touchdown drive on ...
Sinkholes are fairly common, due to collapsed caves, old mines or dissolving material, but the circumstances in South Dakota stand out, said Paul Santi, a professor of geological engineering at the ...