October 04, 2007
Thursday

Home of the trans-Alaska oil pipeline, Alaska has been the setting for a few epic engineering battles rendered against nature. The Million Dollar Bridge, standing almost intact on the lower Copper River, is a reminder of another improbable Alaska construction project.

Completed in 1910, the Million Dollar Bridge was the crux of the Copper River and Northwestern Railway, built to carry copper ore 196 miles from Kennicott to Cordova. Along that route were some of the greatest obstacles Alaska offers-steep canyons, rivers, hurricane-force winds, mosquitoes, and dozens of glaciers.

A fortune in high-grade copper locked deep in the Wrangell Mountains inspired Outside investors, including the Guggenheim family and J.P. Morgan, to risk building a railway from an ice-free port on Alaska's Southcentral coast to the rich copper deposits at Kennicott. In 1906, planners recommended four possible routes to the copper-including two from Valdez to the Copper River via 2,000-foot passes-but railroad builders chose a route from Cordova that would follow the Copper River north to Chitina, then continue 60 miles to Kennicott.

Glaciers stuck out their tongues in defiance along the entire route, but the pull of financial gain and human ingenuity overcame them. In one case, workers laid tracks across the debris-covered ice of Allen Glacier for five-and-one-half miles, according to my two sources for this column: the books, The Copper Spike by Lone E. Janson, and Iron Rails to Alaskan Copper, by Alfred Quinn.

Two of the largest obstacles on the route were Miles and Childs glaciers, both of which calve icebergs into the Copper River from opposite banks. Erastus Hawkins, the engineer in charge of the railroad project, and Michael Heney, the construction contractor, preferred to run the railroad alongside the Copper River, but the Miles and Childs glaciers sprawl over both shorelines at a pinch-point about 15 miles from the river's mouth. Not listening to other engineers who thought the problem was insurmountable, Hawkins designed a 1,550-foot steel bridge to span the Copper River at a river bend between the two glaciers.

Geologists had found that the glaciers had fused during the past several centuries, and the leader of a U.S. Army expedition up the Copper River in 1885 reported that the nose of Miles Glacier was then about 120 yards from the site of the bridge. By 1908, both glaciers had receded to provide a gap of about three miles.

Starting in April 1909, workers scrambled to complete the Million Dollar Bridge, spurred on by a U.S. law that gave railroad developers four years to complete a designated route. After four years, the government would tax them $100 per operating mile per year. Contractors finished the bridge by midsummer of 1910.

Soon after construction of the Million Dollar Bridge (which cost $1.4 million to build), the glaciers continued to threaten the railroad.

In August 1910, two glaciologists from the National Geographic Society studied the sudden advances of both Miles and Childs glaciers. A northern lobe of Childs Glacier began creeping toward the bridge in June, and by August it was moving eight feet per day. On August 17th, the 200-foot face of the glacier was 1,624 feet away from the bridge.

Ralph Tarr, one of the glaciologists, speculated on what would happen if the glacier continued to advance in 1911.

"It is absolutely certain that no corps of engineers could save the bridge and railway if the glacier should advance that far," he wrote.

Childs Glacier did not engulf the bridge, but the glacier crept to within 1,475 feet in June 1911. Childs and Miles glaciers have since retreated, sparing the Million Dollar Bridge, which served the railway from 1910 until 1938, when low copper prices forced the shutdown of the Copper River and Northwestern Railway. The bridge survived nature's whims until March 23, 1964, when the Good Friday Earthquake knocked the northernmost span from its concrete piling.

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