BILOXI, Mississippi (AP) -- When Hurricane Katrina finished pounding this seaside city, it appeared the Beau Rivage hotel-casino had escaped serious damage.It was built to withstand a Category 5 hurricane, and initial reports suggested the $800 million crown jewel of Gulf Coast casinos might recover quickly, a bright spot in an economy desperate for some good news.But a closer look has revealed a gloomier picture. The chairman of MGM Mirage Inc., the Las Vegas-based company that owns the property, predicts the Beau Rivage will be the single-biggest loss of any of the 13 casinos lining the Mississippi coast.Company officials estimate fixing the 1,740-room resort could cost hundreds of millions of dollars and take 12 to 16 months -- a frustrating setback for the 3,400 employees who worked there.The exterior walls appear largely unscathed by Katrina's powerful winds, but the real damage is inside.The MGM Mirage allowed a reporter inside the Beau Rivage for the first time this month, giving The Associated Press a tour of the damage caused by a tidal surge towering more than two stories -- a height the resort's designers hadn't planned for.The company has hired a small army to revive the Beau Rivage, but debris remains visible in all corners of the expansive first floor, the portion that was literally washed away and has since been gutted.Large sections of the southern wall facing the Gulf have huge gashes from the giant waves that crashed into them repeatedly, and the first two floors of the parking garage were wiped away."When you look at it your heart kind of sinks," said Cindy Nieder, a security supervisor and a Beau Rivage employee since the property opened in 1999 -- one of the largest single investments ever made in Mississippi.What remains of the front desk is a pile of battered computers. The atrium has been reduced to rubble thanks to the heavy equipment tearing up the floors. The only people milling around are constructions workers trying to piece the Beau Rivage back together.The gamblers are gone."It was so pretty in here," Nieder said. "We had flowers and little shrubs. It was beautiful."MGM Mirage spent millions improving the Beau Rivage, recently adding a nightclub and new restaurants. Those investments were flushed out to sea. The new $4 million club is gone save the center bar and the coral glass above it.Many seats in the cavernous showroom that holds 1,550 people were yanked out along with the slot machines on the casino floor. Nickels are scattered everywhere.The popular restaurants have disappeared. George Goldhoff, vice president of food and beverage at the Beau Rivage, said his operation was wrecked. A custom-made smoker for barbecuing the meat has vanished."It's not there," he said. "There's no telling where it went."The brewpub's gleaming, stainless steel beer tanks didn't survive, and the four 10,000-gallon aquariums that held sharks and other marine life were flushed out to sea. He had no idea what happened to the creatures."Free Willy, baby," he said.Architects who inspected the Beau Rivage say it's structurally sound because the design helped mitigate and divert the force of the winds. The barge on which the casino rested managed to remain in place.Goldhoff knows he has a daunting rebuilding job in front of him.The thought of it, he said, "makes the hair on my arm stand up."Copyright 2005 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.