WINDSOR, Ont. — A key part of the joint U.S./Canada effort to build a new bridge linking Ontario with Michigan across the Detroit River has been finished, and a positive report made public. It pushes the controversial prospect of a new span downriver from the existing Ambassador Bridge one step closer to reality. A final decision on whether to build the bridge, and where, was once expected to be made this month or next, but it now appears to be further delayed until late spring or even early summer.

The Detroit River International Crossing (DRIC) study teams have completed the technical analysis of their “foundations” investigations into the three favored crossing sites. Simply, they were examining the ground on which a bridge would sit to determine if it could support the colossal weights involved.

DRIC is a joint enterprise of the Canadian and U.S. federal governments, plus those of Ontario and Michigan, working together as the Border Transportation Partnership.

The results of the foundations investigation were reviewed by a bi-national advisory group, 12 experts in foundations, rock mechanics, and geophysics from across North America. Those investigations studied how historic salt-mining activities could affect the crossings being considered. They were undertaken on both sides of the river and are a critical part of the bi-national environmental study. The next step is to complete the analysis of the three crossing options.

“This is an important milestone and brings us one step closer to the development of additional border-crossing capacity,” said Lawrence Cannon, Canadian Minister of Transport, Infrastructure and Communities.

“I am pleased to see the process moving forward. We urgently need a new transportation link at Windsor/Detroit,” said Ontario Minister of Transportation, Jim Bradley. “The time is now – the need is now. Thousands of employees and their employers are depending on us to build a secure, reliable crossing. Our economic future depends on this.”

On the U.S. side, the foundations information has been included in a recently released Draft Environmental Impact Statement. The Michigan Department of Transportation is holding public hearings on the matter in Detroit on March 18 and 19.

U.S. investigations concluded that there are “no subsurface features or conditions associated with solution [salt] mining that might affect the bridge foundations” at two of the three proposed crossing sites.

The third possible site was not included in the investigation on either side of the river because it presented no salt-mining issues.

Canadian conclusions were similar, though not quite so positive: bedrock stability has not been influenced by salt mining at one of the sites, the geologists found, nor have pier locations in either case. But, says the report, “The proposed approach alignment to Crossing C passes over a portion of an historic solution mining area which might affect bedrock stability. In evaluating this crossing alignment the study teams will have to consider the impact this finding will have on the overall study schedule, cost, feasibility, and risk.”

Crossing C, and the plaza that would go with it, are the options closest to the ‘Sandwich’ area of Windsor, said by some to be of historical significance.

If the DRIC decision is to go ahead with a new bridge, it couldn’t be ready before 2013.