Stormy weather delayed weekend efforts to mop up leaking oil from a damaged undersea well after the explosion and sinking of a massive rig off Louisiana's Gulf coast that left 11 workers missing, authorities said. The leak was a new discovery Saturday and could have begun when the Deepwater Horizon drilling rig sank Thursday, two days after the initial explosion that sent smoke soaring high over the northern Gulf, Coast Guard Rear Adm. Mary Landry said. Experts studying the size of the slick and data obtained from remotely operated vehicles estimate up to 1,000 barrels _ or 42,000 gallons _ of oil is leaking each day. The sheen extended 20 miles (30 kilometers) by 20 miles (30 kilometers) Saturday _ about 25 times larger than it appeared to be a day earlier, Landry was quoted as saying by the Associated Press.