Construction of a new Main Salt Lake City Library would require voter approval for a bond to pay for it, but it would also require at least a moderate increase in the operating budget for such a facility.

A new central library is estimated to cost about $50 million. And building projects planned at the Anderson-Foothill and Sprague Branch libraries are estimated to cost another $2 million.City library director Nancy Tessman said Thursday the cost of operating a new main library will require "at least a 10 (percent) to 12 percent increase over our current budget."

The director, other library staff and the library board are excited about the prospects of a new library to replace the 34-year-old main library. But they say it's important for the public to realize a new and larger library will cost more to operate.

Among other things, there would be increased heating and air-conditioning expenses and additional staff in the proposed 200,000-square-foot building. The present structure contains about 115,000 square feet of space.

The City Council has already indicated its support for a library bond, which may be authorized by the council this summer as part of a larger plan to renovate the entire Metropolitan Hall of Justice block on which the present library is located.

The first phase of the larger plan for the block includes demolition of the 3rd District Courts building and parking structure plus construction of a public plaza.

Although the final numbers are still being worked out, the cost of these added projects is estimated at $25 million. So the grand total for everything could add up to $75 million or more.

Council staff has estimated payoff of a $75 million 20-year bond would increase property taxes on a $150,000 home by $38.40.

To prepare for increased operating costs of a new central library, Tessman says the City Council will be presented with two options.

They are to either include approximately $3 million in the bond to pay for materials collection for the new building. Or the council could next year approve an adjustment in the library's tax rate to raise the $3 million for materials over three years and in subsequent years use it for library operations.

Under the current library tax rate, the owner of a home in the city valued at $150,000 pays $62.70. The tax rate has not been increased since 1990-1991, according to a library budget document distributed at Thursday's library board meeting.

"We would not be asking now for the tax rate adjustment. We wouldn't do it until next year's budget. But we are asking that city officials should consider (going on record now) if they agree to the (need for a new library) building. We want them to put the funds for the library materials in the bond now or promise us essentially that we will get the money for the books (and other materials) beginning next year," Tessman said after the library board meeting. Tessman stressed that she wants to make certain that the library is fully disclosing costs for a new and larger building.

"There are capital building costs and future operating costs, and the voters should be fully aware of both of those," Tessman said.