 Gordon Moore Park in Alton will be closed until further notice after a sinkhole opened up at the turf field near the entrance to the park on Wednesday morning. No one above or below ground was injured in the collapse, reportedly caused by surface subsidence according to New Frontiers Materials that operates mining in that area of Alton. The sinkhole, believed to be about 100 feet deep, swallowed a section of the turf between the soccer and football field along with a large lightbulb.