The next, and biggest, issue was cutting a mountain in half and moving soil to fill in Subic Bay and create a  runway. The Seabees blasted coral to fill a section of Subic Bay, filled swampland, removed trees as large as  tall and  in diameter.
A major obstacle was the task of splitting a mountain in two and relocating earth to create a runway for Subic Bay. The Seabees used explosives to fill a portion of Subic Bay with coral, drained swamps, and cleared trees that were as tall as  and wide.