The authority estimates the work will be 31 percent complete by the end of September 2011, if there are no major delays.
The project, which began on Sept. 3 2007, is due to be finished in 2014. It will cost $5.25 billion.
The expansion has been divided into seven areas, the largest of which is the design and construction of the third set of locks, which comprises 60 percent of the cost of the work. The other areas cover dredging and expanding the entrances on both sides of the Canal.
The first and second phases of dry excavation have concluded, and the third phase of dry excavation is 90 percent completed.
Dredging is expected to be about 75 percent completed by the end of September 2011.