Officials say a sinkhole opened up in western Michigan at the site a defunct mine that dates back to the late 1800s.
WOOD-TV reports the sinkhole is along the Grand River near the Blue Bridge and Grand Valley State University's Eberhard Center in Grand Rapids. Crews have removed some old timber that covered the shaft and worked to cover the opening with a gravel mix.
The school says the sinkhole was being caused by dirt moving into the old William T. Powers gypsum mine, which includes a 100-foot (30-meter) mine shaft.
The TV station says the mine operated until 1909, but tunnels remain in the area.
