TAMPA — A phosphate mine in Hillsborough County will be used as a dumping ground for up to 28 million tons of clay — a by-product of mining — from a new Mosaic operation in Hardee County.

The Kelleys and other neighbors are up in arms about a Mosaic plan to use the mine in northeast Hillsborough County to dump clay — a byproduct of mining — from a new mine in Hardee County.