Water managers endorsed a deal today that would give them 2,200 acres of free land in western Martin County while allowing a 1,000-acre rock mine near Lake Okeechobee, despite objections from some environmentalists who said it sets a bad precedent for the rest of the region.

"This is being driven by rock-mining," said Alexandra Larson, an activist from The Acreage, who has been warning about the spread of similar projects across rural land south of the lake. "Nothing's for free. There's a reason somebody wants to dig a hole here."

But leaders of the South Florida Water Management District said they weren't yet approving a final deal, just agreeing to discuss the proposal with the property's owners. Those owners include Wellington cellphone heir George Lindemann Jr., who is notorious in equestrian circles for having hired a hit man to electrocute a show horse in 1990.

"This, for me, is as close to a no-brainer as we've seen," said board member Mike Collins, an Islamorada fishing guide. "We wanted to buy this property."

And now, the district can get it for no money at all.

But other board members, including Chairman Eric Buermann, said they take the critics' qualms about mining seriously.

"I have a natural suspicion," said Buermann, a Miami lawyer. He said he'll want the district's staff to make sure the final deal benefits the environment.

Martin County commissioners also agreed this week to explore the proposed land swap.

Lindemann has proposed giving the land, part of which is approved to build pony farms for polo players, to the district to use for stormwater treatment and water storage.

In exchange the county and water district would have to allow Lindemann to mine 1,000 acres for limestone, which is used in construction, over the next 20 years. Lindemann has said most of his limestone will be sold to the U.S. Army Corps of Engineers to repair the Herbert Hoover Dike.