NEW ORLEANS -- The cap over a broken BP wellhead at the bottom of the Gulf of Mexico is collecting more gushing crude day by day, but that's about the extent of the details known as authorities try to pinpoint how much oil is escaping, where it's going and what harm it will cause.
The recently installed containment cap on the stricken BP wellhead is helping to limit the leak, collecting more than 620,000 gallons of oil Monday, Coast Guard Adm. Thad Allen said Tuesday in Washington. Still, underwater video feeds continue to show a dark geyser.
''I have never said this is going well,'' said Allen, who's monitoring the response effort for the government. ''We're throwing everything at it that we've got. I've said time and time again that nothing good happens when oil is on the water.''
Authorities had earlier reported that the cap collected around 460,000 gallons Sunday and that it was capturing anywhere from a third to three-quarters of the oil spewing out after a damaged riser pipe was cut as part of the containment effort, increasing the flow as a side effect.
University of Texas engineering professor Paul Bommer, a member of the Coast Guard team that's trying to determine how much oil is still leaking, told The Associated Press it's possible that estimates the team will generate could be a bit higher than current government estimates.
BP announced plans recently to swap out the current cap with a bigger one next month that can capture more oil, raising questions about why such plans weren't in place at first as a backup.
''I know it takes some time to fabricate these things,'' Bommer said. ''It's not something you just go to Wal-Mart and buy.''
The current equipment collecting the spilled oil at the surface is believed to be nearing its daily capacity. BP spokesman Max McGahan told the AP the company will process some of the flow by sending it to a burner that turns it into a combustible fog and ignites it.
The rig equipped with the burner will be moved away from the main leak site so flames and heat do not endanger other vessels, he said.
BP will also boost capacity by bringing in a floating platform it believes can process most of the flow, spokesman Robert Wine said. He didn't know when it would arrive.
Bommer's team, the Flow Rate Technical Group, includes federal scientists, independent experts and academic researchers, and its projections could ultimately be used to penalize BP judging by how much oil escapes.
BP CEO Tony Hayward is scheduled to testify before a congressional committee June 17 about the company's role in a rig explosion April 20 that killed 11 workers, and the ensuing spill.
Hayward enraged many when he later said, ''I'd like my life back,'' and is sure to receive pointed questions from lawmakers about the cause of the accident and the response to it.
President Barack Obama, who on Monday told NBC's ''Today'' show that he had met with fishermen and experts so he knew ''whose ass to kick'' over the spill, plans to visit the region Monday and Tuesday for a fourth time since the crisis began, the White House said.