Cost: between $3.1 and $4.35 million

Annually: between $239,000 and $505,000, over 20 years

Complicating the demolition is the Florida Power & Light facility, which retains a federal license to generate power. Any demolition of Mill No. 5 would have to accommodate the hydro facility and take care that it not disturb the canal system on which it relies.

On the upside, the city would have a four- to eight-acre parcel centrally located between downtowns on one of the busiest traffic routes in Maine to offer for development, in concert with a master plan. On the downside, it would lose the architectural uniqueness of a historic mill building.

One crucial variable: The city is already late in green-lighting the next municipal garage, a contractual obligation it must meet under the 2004 Bates Mill Redevelopment Agreement. It’s possible the garage would be sited on Mill No. 5’s eight acres, since the city already owns the property. If so, the garage – which might take up as much as four acres – could restrict future development of the parcel.

It’s also unclear whether federal grant money ($882,000) used to reroof the building means permission must be obtained from the Economic Development Administration before razing could begin.

Convention Center

Cost: Between $40 million and $58 million to build. Any commitment of city money would require a referendum first.

Annually: It takes five years for a convention center to get established. After that, figure on operating losses of $237,000 each year. Those losses could be offset from taxes generated by the $47 million in spin-off businesses and 500 new jobs expected in the convention center’s wake.

Five feasibility studies show that a Lewiston convention center would be well positioned to draw from northern New England. A study by the Convention & Visitors Bureau of Greater Portland released last month showed that city lost $8 million in potential business in 2007 from groups that expressed an interest in holding a convention in Portland, but went elsewhere because of a lack of facilities.

The last study for Mill No. 5 settled on an 80,000-square-foot concept, about one-fourth of the available square footage at the mill. Task force members recommended the remaining space become a permanent home for Museum L/A, other cultural uses, restaurants, shops and entertainment. Platz Associates, which has done some preliminary work on the concept, has a model in its Auburn office that shows much of the second floor of the mill removed. The remaining portions create a mezzanine around the exhibition space below.

City officials have always promoted the convention center as a public/private endeavor, showing the mill to organizations such as the Libra Foundation for possible partnership. Nothing so far. A proposal to launch a $245 million convention center complex in Portland died in 2005 when the state failed to pass a local-option sales tax, revenue which would have been earmarked for a facility there.

Adaptive re-use

Cost: $13 million for basic rehab work to make the building marketable; $200,000 for a national marketing campaign

Annually: $250,000 to $350,000 carrying cost, plus rehab and marketing costs

If not a convention center, then what? Task force members initially considered, then rejected, the idea of soliciting requests for proposals because the scale of the building would limit interest from private investment and an RFP would carry a strict timeline.

But public arguments in favor of an RFP option reversed the task force’s decision. New and ingenious uses for the mill might come from soliciting bids from private developers on a national level. Re-use would be based on a master plan and community vision that boosts the local economy and improves the community.

One plus: Most of the environmental cleanup work has already been done – a significant savings for redevelopment.