Facebook Inc., operating as Project Sequelant, will present a site plan Tuesday to the Altoona Planning & Zoning Commission for a $250 million, 1 million-square-foot data center at its campus.

As part of the data center expansion, Peoria, Ill.-based Valley Development Co. will ask the commission to rezone about 58 acres of property south of 25th Street Northwest at Northeast 62nd Street from an agriculture designation to limited industrial.

Facebook currently owns 376 acres in Altoona, with 1.6 million square feet of structures completed or under construction.

Facebook is in the final stages of construction of its third 1 million-square-foot data center at the Altoona campus.

Altoona City Administrator Jeff Mark said efforts are ongoing to reach a development agreement with the company. As part of Facebook’s inaugural appearance in Greater Des Moines, Altoona provided a 20-year, 100 percent abatement of property taxes. That package was part of a state requirement that communities provide a local match as a condition for state development incentives.

The present assessed value of Facebook land and buildings is $450 million.

The Iowa Economic Development Authority board approved $18 million in tax credits for the first phase of Facebook’s construction in 2013 and in 2017 amended that award by adding $8 million in sales tax relief on construction costs. As part of the 2017 amendment, Altoona satisfied its local match requirement via the franchise fee on utilities.