Oil giant BP has succeeded in connecting a mile-long pipe to capture the oil flowing into the Gulf of Mexico, a company spokesman said Sunday.

“We are restarting the operation now” to siphon oil to a above-water ship, said BP spokesman David Nicholas. He said the company had succeeded in connecting the tube Saturday night, but ran into a glitch and had to stop the process, which it restarted Sunday.

The effort to connect two pieces of equipment a mile below the water’s surface had also previously failed on Saturday.

It is unclear if the effort will totally cap the massive spill.

Word of huge submerged oil plumes, meanwhile, raised the specter of more damage to the ecologically rich Gulf. It also adds to questions about when large amounts of crude might hit shore. So far, tar balls have been sporadically washing up on beaches in several states, but oil hasn’t come ashore in big quantities.

Researchers from the National Institute for Undersea Science and Technology said they had detected the underwater oil plumes at depths between just beneath the surface to more than 4,000 feet.

Three or four large plumes have been found, at least one that is 10 miles long and a mile wide, said Samantha Joye, a marine science professor at the University of Georgia.

(Read More: Miami Herald)