Arcadia, Fla. — The Mosaic Co. has opened offices in the newly restored Hollingsworth House here in a move that is considered a first step toward gaining approvals for phosphate mining of some of the thousands of acres the company owns in DeSoto County. Mosaic says the location, which overlooks the county administration building in downtown Arcadia, will serve as the company’s base of operations and will provide office space for community relations and permitting staff members. At the same time, Mosaic is renovating a second building behind the Hollingsworth House, which is one of the area’s historic homes, to serve as a community room to host the company’s DeSoto County Citizens Advisory Panel meetings and other community events. Since its formation in 2004, Mosaic has owned more than 18,000 acres of future phosphate mine land in DeSoto County. Within the next 10 years, the company is poised to invest more than $1 billion in construction and infrastructure costs to develop a world-class phosphate mine in the county, which will eventually provide nearly half of the company’s Florida phosphate rock production. The facility is expected to employ approximately 400 full-time employees, with wages and benefits averaging significantly higher than the currently reported average median income in DeSoto County. The mine will also provide employment for hundreds of full-time contractors. According to a recent study, economic activity resulting from the mine’s operation will produce thousands of jobs in DeSoto County and beyond. But the situation may not remain so upbeat much longer. Environmentalists, including the Sierra Club, are expected to press their opposition to the mining.