Rivers Casino finally can get down to business.

The state Supreme Court has removed the final legal hurdle in its path, throwing out an appeal filed by Riverlife and two North Side residents challenging the height of the casino's massive 3,872-space garage.

With the ruling, the North Shore casino, located just west of the Carnegie Science Center, can speed toward its proposed August opening free of the legal challenges that have dogged it for more than two years.

"We really have been plowing ahead anyway. We had a high degree of confidence [in a favorable ruling]," said Ed Fasulo, casino general manager.

The hulking nine-story parking garage, nearly twice the size of the casino, has triggered protests from many in the design community who fear its size would detract from the sleek-looking slots parlor and mar views from Mount Washington and other locations.

Riverlife, a public-private agency that promotes riverfront redevelopment, took its battle to court after the city planning commission approved the building shell in January 2008. It argued the above-ground garage, at 119 feet high, varied from the original design, which showed the two levels underground, and violated the city zoning code.

The Supreme Court never got to the merits of that argument. It ruled the Riverlife appeal was untimely because it was not filed within the required 30 days after the planning commission had approved the garage's height nearly six months before.

In legal filings, the planning commission and PITG Gaming LLC, the former casino owner, contended the garage height was settled in August 2007, when the commission approved site utilities, foundation construction and the erection of structural steel.

The Supreme Court agreed and quashed the appeal.

Riverlife proved to be anything but a sore loser.

"We see this ruling as an old chapter involving the previous developer. We have moved forward, working in partnership with the new ownership, [which has] committed to building a full-scale riverfront park, and we are working on amenities that will benefit the people of Pittsburgh," Riverlife Executive Director Lisa Schroeder said.

Holdings Acquisition Co., a group led by Chicago billionaire Neil Bluhm, replaced Don Barden and PITG Gaming LLC as primary owner last summer after Mr. Barden was unable to secure permanent financing for the $800 million slots parlor.

Because of the garage controversy, the casino agreed to spend $1.2 million to install decorative screening around the parking structure. Mr. Fasulo said workers already have started doing so on the west side of the garage.

The casino is on pace to open between Aug. 1 and Aug. 10, Mr. Fasulo said. Much of the exterior has been completed, and much of the glass, including for a 90-foot drum atrium, is being installed.

Mr. Fasulo said the interior is still "very, very rough," although dry wall is up and some painting has started on the second floor, which will house administrative offices and a buffet. Mr. Fasulo hopes there will be enough progress to install the first slot machines around May 1.

Work also has started on the Ohio River bank, where there will be a dock, an outdoor amphitheater, and walkways leading to a riverfront promenade. About 420 people are now working at the site.