PPL Montana Continues Work on Hebgen Dam Intake Structure Project

January 10, 2013

Construction on the Hebgen intake structure project has continued successfully through late 2012.

“We have been closely monitoring the cofferdam since high stresses were discovered in August 2012,” said David Hoffman, director of external affairs for PPL Montana. “The dewatering wells that were installed have been effective at reducing stresses on the cofferdam and no additional concerns have arisen.”

New equipment was installed to allow PPL Montana to observe and record data from the cofferdam in real time, even after work has been suspended for the season.

Work has also been completed on several sections of reinforced concrete that will be part of the permanent rehabilitated structure. New structural concrete construction will continue through the 2013 season. The new concrete structure is extensively anchored to the existing structure and is heavily reinforced. The work sequence required the concrete to be placed on subsequent lifts from the bottom up.

And, in addition to the usual tasks that facilitate material delivery, worker access and safety, activities such as shoring, formwork, tying rebar, drilling and epoxying dowels, and jackhammering were used to support the concrete placement.

“In addition to the concrete construction, plans are currently in place to construct additional multi-strand anchors behind the intake structure and above the water line this winter,” Hoffman said. “We are proud that PPL Montana’s commitment to safety is a top priority.”

PPL Montana also reminds the general public to be very cautious on ice near the dam. Ice has formed later than normal this year on all area lakes. At Hebgen, the ice near the spillway by the public access site will be thin for some time after flow is switched from the spillway to the intake. PPL Montana will coordinate with Gallatin National Forest to open the Hebgen Dam access site for ice fishing in mid-January.

PPL has 500 employees in Montana who generate and sell electricity. PPL Montana operates coal-fired power plants at Colstrip and Billings, as well as 11 hydroelectric power plants along Rosebud Creek and the Missouri, Madison, Clark Fork and Flathead rivers. It has a combined generating capacity of about 1,200 megawatts and has offices in Billings, Butte and Helena. PPL EnergyPlus operates a trading floor in Butte that markets and sells power in the wholesale and retail energy market. PPL Montana and PPL EnergyPlus are subsidiaries of PPL Corporation (NYSE: PPL). More information about PPL Montana is available at www.pplmontana.com.