With a sheen of oil as far as the eye can see, the Joe Griffin arrives at the rig explosion site carrying the containment vessel which will be used to try to contain the Deepwater Horizon oil, Thursday, May 6, 2010. AP Photo via sunherald.com

By HARRY R. WEBER and CAIN BURDEAU – Associated Press Writers ON THE GULF OF MEXICO — It’s never been tried before, but crews hope to lower a 100-ton concrete-and-steel box a mile under the Gulf of Mexico on Thursday to cut off most of the hundreds of thousands of gallons of oil spewing from a blown-out well. If it works, the system could collect as much as 85 percent of the oil that’s been leaking from the ocean floor after the Deepwater Horizon rig exploded April 20, killing 11 workers. “Hopefully, it will work better than they expect,” first mate Douglas Peake told The Associated Press aboard the ship that brought the box to the site. The AP is the only news organization with access to the containment effort. It won’t solve the problem altogether. Crews are drilling a relief well to take the pressure off the blown-out well at the site, and that could take up to three months. Other possible solutions are also in the works. More than 200,000 gallons of oil a day is pouring from the well, creating a massive sheen that’s been floating on the Gulf for more than two weeks. As it moved closer to land, crews were frantically laying boom and taking other steps to prevent it from oozing into delicate coastal wetlands. At sea, some boats were using skimmers to suck up oil while others were corralling and setting fire to it to burn it off the surface. The Joe Griffin, the ship carrying the containment box that will be lowered to the seafloor, arrived Thursday morning at the leak site about 50 miles offshore. Workers hope to have the device down at the seabed by Thursday evening, but it will likely be Sunday or Monday before it’s fully operational and they know if it’s working.

Boat with containment box at oil site