ROBERT, La. (AP) - BP's chief executive says we won't know until Sunday if pumping heavy mud into a blown-out well on the seafloor is successful in stopping the massive Gulf of Mexico oil spill.
CEO Tony Hayward said on the CBS "Early Show" that his confidence level in the well-plugging effort remains at 60 to 70 percent.
BP began injecting mud into the well on Wednesday afternoon in hopes of plugging the gusher, then stopped the process for 18 hours yesterday to assess its efforts and bring in more materials.
The company said the "top kill" procedure is going well, though some drilling mud was escaping from the broken pipe. A spokesman says the situation "isn't ideal but it's not necessarily indicative of a problem."
BP says it's considering shooting small rubber balls or assorted junk into the failed blowout preventer to keep the mud from escaping.
Meanwhile, marine scientists say they have spotted a huge new plume of what they believe is oil, stretching 22 miles from the leaking wellhead northeast toward Mobile Bay, Ala. They fear it could have resulted from using chemicals a mile below the surface to break up the oil.
President Barack Obama visits Louisiana today for a firsthand update on the efforts.