Demolishing Mellon Arena would make way for a mix of new homes and high-end office space covering nine city blocks in the lower Hill District, according to a study released Wednesday.

The 107-page report provides the first detailed look at six scenarios, which include restoring the arena to its original 1961 design; mothballing it indefinitely; preserving its unique silver dome; and razing it to build 1,191 residential units and 608,000 square feet of offices.

Representatives of the city-county Sports & Exhibition Authority said last week that they favor demolishing the Igloo and allowing the Penguins to build a mixed-use development — a plan referred to as “Option 5” in the study, prepared by consultant Michael Baker Engineering of Moon.

The firm organized seven meetings and a tour of Mellon Arena for public input. The lengthy report is the result and is open to public comment and revision.

The SEA, which owns Mellon Arena, will consider comments on the report before the authority’s board of directors makes a decision on the arena’s fate, said Chris Cieslak, a consultant working with Oxford Development and the SEA.

“What we don’t want is what has happened in Portland, Oregon, where they have talked about it for nine years and the city of Portland has had to pay the holding costs on (Memorial) Coliseum,” Cieslak said. Groups have opposed razing the Pacific Northwest arena.

Penguins President David Morehouse said the team agrees with the report’s findings, which correspond to a market analysis performed by Penguins consultant AECOM.

He wants demolition of Mellon Arena to begin in a year. The team owns the rights to develop the site.

“The last thing we want to do is put an impediment in front of a developer and say: ‘We want you to put this development in but, by the way, you have to put it underneath this dome,'” Morehouse said. “The people proposing that have no developers and no money for that.”

Those trying to save the arena from destruction are surprised by the study’s release. Architect Rob Pfaffman, founder of the Reuse the Igloo group, said he wasn’t aware the full report was available until told by a reporter.

Pfaffman’s vision is to build a boutique hotel inside the arena with retail and open-air park space.

“They have gone on the record, at least with us, that they prefer Option 5,” Pfaffman said. “We don’t think the process was properly followed.”

Pfaffman’s preservation group hired its own consultant to examine alternatives to tearing down the 49-year-old arena — the National Hockey League’s oldest venue. Mellon Arena will be replaced by the $321 million Consol Energy Center when it opens in August across Centre Avenue.

Pfaffman said if the SEA was sincere about finding alternatives to demolishing Mellon Arena, the authority would conduct a more detailed study and perform an engineering analysis of the building.

Neither has occurred.

The study said that in addition to making room for office space and homes, demolishing the arena would allow three north-south streets to be built. The streets would connect Bedford and Centre avenues — roads that planners eliminated when building the arena.

Razing the arena also would provide space for 208,750 square feet of retail development; a 150-room hotel; 2,145 parking spaces; and 57,560 square feet of “public open space located along pedestrian corridors,” the study said.