Boulder Community Hospital has closed a deal to sell its historic Mapleton Center property -- first home to the Boulder-Colorado Sanitarium in the late 1800s -- to private developers for $12.9 million, although plans for the nearly 15-acre site are not yet known.

Jay Hebb, the purchasers' broker at Boulder's RE/MAX Alliance, said the hospital will retain ownership of the 311 Mapleton Ave. property for the next two years and provide rehabilitation services there while Boulder-based buyers Crystal Ridge LLC explore options for the site and work with the city on redevelopment.

"It's a very special piece of property in Boulder, and the buyers are excited about the opportunity and really looking forward to re-gentrifying one of the city's most coveted properties," he said.

Boulder Community Hospital is in the midst of a 10-year, $125 million project that involves the relocation of its acute care operations to its Foothills campus from its Balsam Avenue facility. In later phases, Boulder Community will renovate its Balsam property so that it can serve as the base of operations for the rehabilitative services now housed at Mapleton.

"We're basically going from three facilities to two," said Rich Sheehan, Boulder Community Hospital spokesman.

He said the sale of the property won't change the timeline for moving the Mapleton services.

The Mapleton property was valued at just over $14 million, according to Boulder County assessor records. That valuation -- based off market prices in 2010 -- most likely was determined by a cost approach in which the assessor valued the land using the going rates for the commercial price of land in that area, incorporated the cost to construct the building and then accounted for depreciation, Boulder County Assessor Jerry Roberts has said.

When asked about the more than $1 million difference between the assessed price and the sale price, Sheehan said, "That's just the final price."

The buyer, Crystal Ridge LLC, was formed in December by Hassan and Cables LLC, a Boulder law firm with an emphasis in business and real estate law.

The Mapleton property was originally home to the Boulder-Colorado Sanitarium, which opened in 1896. The sanitarium was run by the Seventh-day Adventist Church and founded by Dr. John Harvey Kellogg, who opened his first sanitarium in Michigan.

Kellogg, whose first claim to fame was in rolling and flaking kernels of corn, experimented with combinations of nuts and grains conveniently prepared into granola and other cereals on the Boulder facility's grounds.

Through several renovations extending into the 1950s, the sanitarium was replaced by Boulder Memorial Hospital, which later moved and evolved into the Avista Adventist Hospital in Louisville.