Florida Rock Industries ( FRK), a construction materials company, said Thursday a U.S. District Court ruled that several mining permits for the Lake Belt area in South Florida had been improperly issued. This ruling affects most of the 12 mining permits issued for this area, including the permit issued to the company's Miami quarry. The Court remanded the permitting process to the U.S. Army Corps of Engineers for further review and consideration. Florida Rock sold 4.2 million tons of aggregates from its Miami quarry, which generated $36.4 million revenue for the year ended Sep. 30, 2005. If mining is allowed in the long term, the company estimates that recoverable reserves at the Miami quarry are around 139 million tons. Florida Rock intends to appeal this ruling while at the same time seeking re-issuance of the permit. The company's shares dropped 52 cents to $56.88.