Construction of new locks for the Panama Canal is about 42% finished. The lock work was considered the most complicated and costly part of the $5.25 billion expansion project. Work is about eight months behind schedule, primarily due to issues with concrete mix for the locks. Work on the Atlantic side of the canal is progressing more quickly than on the Pacific side because of excavation work. "We can learn from the Atlantic side while the Pacific is still getting ready," said Jorge de la Guardia, executive director of the project. "It will be like going to school for the canal pilots and tugboat operators."