Published: Jun 20, 2010 8:32 PM EDT
Updated: Jun 20, 2010 5:32 PM EDT

ON THE GULF OF MEXICO (AP) - Drilling crews are grinding deeper as they work on relief wells aimed at stopping the massive oil leak at the bottom of the Gulf of Mexico.
      
The crew of Transocean Ltd.'s Development Driller II was expected to start pouring cement today to firm up a section of metal casing lining one of the two relief wells.
      
BP and government officials say the wells are the best option for cutting off the gusher that has spilled as much as 125 million gallons into the Gulf since the Transocean drilling rig Deepwater Horizon exploded two months ago today, killing 11 workers.
      
The relief wells aren't expected to be finished before August.