Work on a project that will bury forever one of the last quirky remnants of Tacoma’s Ruston Way industrial waterfront, the Ruston tunnel, begins today.

Ruston Way near the former Asarco copper smelter site at the north end of that waterfront roadway will be closed for two weeks so new utilities can be installed under the roadway. Detour signs will be posted.

That temporary closure, which is scheduled to end Nov. 25, is a preview of what will happen next spring when the $15.5 million road and utility relocation project is finished and the tunnel closes forever.

That project will replace the tunnel with a new road that will connect Ruston and the Ruston Way waterfront. That new road, about 400 feet closer to the water than the present connection through the tunnel, will also serve the $1 billion Point Ruston urban development being built on the old copper smelter site.

The narrow tunnel, built in the 1930s to carry the street around the smelter site, is beginning to fail structurally and is leaking water filtered through the contaminated soil above it onto the roadway. The tunnel, barely wide enough for two cars to pass and a hazard for bicyclists, doesn’t meet modern roadway standards, said Mike Cohen, president of the development company building Point Ruston.

The tunnel has a sharp bend at its northern entrance, limiting incoming vehicles’ sightlines into the tunnel. Many drivers honk their horns before entering from the north to let cars already in the tunnel know of their imminent entry into the passage.

The replacement plan calls for building the new roadway first and then closing the tunnel shortly before the new road is hooked up to roadways at either end.

The tunnel itself, Cohen said, will be filled with low-level contaminated soils removed from residential yards in the area and then sealed. The entrances will be covered with clean fill, leaving no trace where the tunnel is buried. The tunnel could be demolished, but doing so would affect the adjacent railroad tunnel above it, so the plan to fill the vehicle tunnel and bury it was devised, Cohen said.

The joint BNSF-Union Pacific main line follows the Ruston Way waterfront and cuts under Stack Hill in the short tunnel adjacent to the vehicle tunnel. The track then bursts into the open for a short distance before diving into the much longer Nelson Bennett tunnel under Point Defiance. The track emerges near Salmon Beach on the Tacoma Narrows.

The roadway and utility construction is being financed through the City of Tacoma using a local improvement district bond issue. That LID will allow construction funds to be borrowed at the city’s lower interest rate. The LID bonds will be paid back over the next two decades by owners of the affected property.

The city agreed to let Cohen’s company handle the construction because the company is familiar with the environmental requirements for working on the site.

The Asarco copper mill, which closed in the mid-1980s, smelted and refined high-arsenic copper ore. The mill produced copper, arsenic and several other metals. Arsenic dust contaminated many nearby properties, and its presence was detectable as far away as Vashon Island and South King County. The copper mill site itself is an environmental remediation area that requires special procedures to keep contamination from spreading.

Cohen’s company is planning to build condominiums, single-family homes, apartments, offices and retail spaces on the cleaned-up site. A Silver Cloud hotel also is scheduled to be built on the Point Ruston waterfront site.

The company has built a half-dozen luxury homes on the hill overlooking the former smelter site where the smelter’s towering stack once stood. The garage for the first condominium building is nearly complete, but Cohen has put construction of the condo building, Copperline, on hold until the utility work serving the development and the new road is done. The weak market for new condos also is delaying the project, he said.

The work being done in the next two weeks will include installing new utility lines under the present Ruston Way roadway.

The roadway will include two roundabouts, allowing drivers to peel off to a new boulevard serving Point Ruston, to continue uphill toward Ruston or to head toward what will become the Tacoma Yacht Club’s new entrance.

Those same roundabouts also will allow drivers to reverse direction easily and head south again on Ruston Way.

“It should make it easier for the cruisers on Ruston Way,” Cohen said.

“They won’t have to make a U-turn in a parking lot like they do now,” he said.

The tunnel is one of the last reminders of an era when the Ruston Way shoreline was filled with industrial activity, flour mills, shipyards, warehouses, docks and the copper smelter. The shoreline is now a linear park punctuated by restaurants and offices.

John Gillie: 253-597-8662

john.gillie@thenewstribune.com