 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 around 100 feet deep, swallowed a section of the turf between a soccer and football field, along with a large light pole. Alton Mayor David Goins addressed the issue at Wednesday's city council, saying out of an abundance of caution, they decided to close the entire park until it can be checked by experts. There will be an independent geologist