SAULT STE. MARIE, MI — With only closeout items remaining, the U.S. Army Corps of Engineers, Detroit District’s New Lock at the Soo substantially completes its first phase of construction.

“We are waiting on final survey results and anticipate they will show the deepened areas as complete, really only have some punch-list type items, groundskeeping, and site cleanup remaining,” said project Supervisory Civil Engineer Rachel Miller.

Trade West Construction, Inc., of Nevada, a small business, began deepening the upstream channel May 4, 2020.

“The New Lock was first authorized in 1986. That’s 36 years ago,” said New Lock at the Soo Chief Mick Awbrey. “It went through a series of changes and reauthorizations, then the Corps of Engineers was able to begin construction in 2020. Reaching substantial completion of this first phase of construction is a monumental milestone.”

Using a submergible excavator attachment called a hydraulic ripper, Trade West broke up bedrock approximately six feet thick over a three-quarter mile long stretch, primarily sandstone, from the north channel to a 30-foot depth. The channel depth is needed to accommodate the large Great Lakes freighters.

In all, around 300,000 cubic yards of material, including bedrock and overburden was removed using the ripper, stone grinders, and excavator buckets. These operations were all done from barges. The material removed from the channel was placed onto the Northwest Pier’s west end to act as a windbreak for passing ships. The largest rock weighed 55 tons, about the same weight as an adult humpback whale.

Two major phases of the project remain for the New Lock. Phase 2, rehabilitating the upstream approach walls, began in 2021. Following the winter downtime, season two work began again this year in mid-April. This work stabilizes the existing approach walls to allow modern vessels to tie up and wait their turn to pass through the New Lock. The Phase 2 contractor is Kokosing-Alberici LLC, a joint venture of Kokosing Industrial of Ohio and Alberici Constructors of Missouri. They are on track for completion by summer 2024.

The Detroit District awarded Phase 3 on July 1. It is the largest and most complicated phase and involves constructing the new lock chamber and rehabilitating downstream approach walls.

Over 88 percent of commodity tonnage through the Soo Locks is restricted by vessel size to the Poe Lock. The new lock project will construct a second Poe-sized lock, 1,200 feet by 110 feet on the site of the existing decommissioned Davis and Sabin locks.

“We’ll build coffer cells to block off and dewater the construction site,” Miller said. “Power needs to be rerouted through the facility, the Sabin Lock chamber demolished, a new 1,200-foot by 110-foot chamber constructed, the Davis Lock filled in, a new pump well installed, and the downstream approach walls rehabilitated.”

The Soo Locks are situated on the St. Marys River at Sault Ste. Marie, Michigan, and allow vessels to transit the 21-foot elevation change at the St. Marys Falls Canal. According to a 2015 Department of Homeland Security study on the impact of an unexpected Soo Locks closure, the Soo Locks are nationally critical infrastructure and the reliability of this critical node in the Great Lakes Navigation System is essential to U.S. manufacturing and National Security.