Published: May 27, 2010 7:25 AM EDT

ROBERT, La. (AP) - One of BP's top executives says crews trying to plug a massive Gulf oil leak are pumping mud into a blown-out well as effectively and efficiently as they had hoped.

BP PLC Chief Operating Officer Doug Suttles said Wednesday night that the company would continue to monitor the procedure known as a top kill and that officials should know in the next 24 hours whether it has been successful.

The top kill has never before been tried a mile beneath the sea. Engineers plan to follow up the mud with cement that the company hopes will seal the well. The Coast Guard says 100 miles of coastline in Louisiana is being hit by oil.