Related Group can move forward with its plans to build a luxury apartment tower on the site where the remains of an ancient civilization that archaeologists say dates back 7,000 years were found.

The developer struck a deal with the Miami Historic & Environmental Preservation Board, which voted unanimously Tuesday night to withdraw its proposed protected landmark designation of 77 Southeast Fifth St., where a team of archaeologists has spent the past 18 months carefully extracting artifacts that are the remains of a settlement from the Tequesta tribe near the mouth of the Miami River, the Miami Herald reports.

The board also voted to set protections on the adjacent site, 444 Brickell Ave., where Related Group plans to tear down a 10-story office building and Capital Grille restaurant to build a luxury condo tower. The votes came after a contentious, five-hour hearing in which preservationists, community members and developers testified.

Related Group, founded by billionaire Jorge Perez and run by his son, Jon Paul Perez, acquired the sites for $104M in 2013 and secured a $164M construction loan to develop an apartment tower at 77 Southeast Fifth, where foundation work has already begun. It is also planning to build a branded luxury condo tower, the Baccarat Residences, on the north end of that site, where archaeological work is underway.

Related executives said at the meeting they have spent $20M on the excavation efforts thus far, and that preventing development would cost it "hundreds of millions of dollars," the Herald reported. The developer is required by law to hire archaeologists when evidence of prehistoric artifacts are found.

Several Native Americans at the hearing said the development is a "desecration" of an ancient burial ground since human and animal remains have been discovered at the site. Postholes, indicating foundations of ancient buildings, as well as stone tools and weapons have been found at the site.

Archaeologists said the extent of the findings and their antiquity make it one of the most important sites in Florida, although Related's architectural consultants said they think its origins are closer to 2,500 years old than 7,000, the Herald reported. City preservation officials concluded the entire site meets the criteria for a protected historical landmark.

As part of the development, Related Group is planning to display some of the artifacts as well as construct a walkway under the Brickell Avenue bridge to connect to the Miami River historic site, another remnant of the Tequesta settlement that is roughly 2,000 years old and was unearthed in 1998.

The votes mean that the preservation board will formally consider designating 444 Brickell Ave. a historic site — allowing it to review and modify its development — before a final vote in July. Related is now required to draw up a "preservation action plan" for 77 Southeast Fifth within six months of the conclusion of the archaeological work, the Herald reported.