Liberty Mutual Group Inc., the Boston-based insurance conglomerate, has leased a major portion of the Meadowwood Technology Campus, where it plans to open operations in the spring, following a big tenant improvement project, sources in Liberty Lake say.

Amanda Tainio, Liberty Lake's planning and building services manager, says the project involves about 100,000 square feet of floor space on both floors of the main building on the campus.

The city estimates the value of the planned tenant improvements at $4.5 million, she says.

Meadowwood Partners LLC, a subsidiary of Liberty Lake-based real estate developer Greenstone Corp., owns the campus, which includes the 250,000-square-foot main building.

Wayne Frost, a Greenstone vice president who handles the company's commercial division, says Greenstone is removing some walls inside the building, and Liberty Mutual will handle most of the tenant improvements.

Liberty Mutual is scheduled to occupy the space in April, Frost says.

Calls to Liberty Mutual's office here were directed to the company's corporate office, where Christopher Goetcheus, a company spokesman, declines to comment.

Tainio says Turner Construction Co., of Seattle, is Liberty Mutual's contractor on the project, and Bernardo Wills Architects PC, of Spokane, designed the improvements.

Liberty Mutual currently conducts some operations about a mile east of the Meadowwood site, at 22425 E. Appleway in Liberty Lake, where its Seattle-based insurance subsidiary, Safeco Corp., also operates a claims division and a customer service center.

Dick Vandervert, who heads Vandervert Construction Inc., of Spokane, says his company had been in discussions with Liberty Mutual to erect a new building on the West Plains that would house its operations here. Those discussions cooled down, Vandervert says, and he learned recently that the Liberty Mutual has decided to lease a different property.

Doug Byrd, broker at Byrd Real Estate Group LLC, of Spokane, says he's the leasing agent for the space that Liberty Mutual plans to vacate in the building on Appleway.

He has listed 95,400 square feet as available for lease there. A couple of prospects are interested in the space, but Byrd declines to identify them.

The Meadowwood Technology Campus, located at 24001 E. Mission, east of Molter Road on the north side of Mission Avenue, is the former site of the Agilent Technologies Inc. complex, which Greenstone bought last year.

Santa Clara, Calif.-based Agilent, a scientific-instrument maker that once employed 1,200 people in the Spokane area, shut down its operations here entirely last year after reducing its Liberty Lake work force over a number of years.

Liberty Mutual will be by far the largest tenant on campus since Greenstone bought it, Frost says. Other tenants there include Demand Energy Networks Inc. and Ptera Wireless Inc., which lease 8,000 square feet of floor space and 3,000 square feet of floor space, respectively.

Greenstone announced when it bought the 70-acre property that it plans eventually to expand the campus into a multibuilding complex with as much as 700,000 square feet of space, to accommodate up to 4,500 workers.

Liberty Mutual employs 45,000 people in more than 900 offices worldwide and reported revenues of $33.2 billion in 2010, its website says.