BILLINGS — A failed Exxon Mobil pipeline that spilled an estimated 42,000 gallons of oil into the Yellowstone River was expected to restart operations Saturday after getting approval from federal officials.
Changes made during repairs to the Silvertip pipeline have made it less likely to fail again, Montana Department of Environmental Quality Director Richard Opper said. The line broke July 1 after flooding scoured the river bottom and exposed the 12-inch pipe, which was buried just five feet deep in some areas.
A replacement segment was installed by drilling a new passage for the pipeline an estimated 60 to 70 feet beneath the riverbed.
"There were a lot of eyes on this from our federal partners," Opper said of repairs to the line. "It was done right. It's a lot safer pipeline now, at least crossing the river."
Company spokeswoman Rachael Moore confirmed Friday that pipeline safety regulators had approved the resumption of operations along the pipe that runs beneath the river near Laurel.
The flow of oil will resume once integrity checks have been completed on the line, Moore said. She declined to say when that would be, but Opper said he was told Saturday.
Two more of the line's river crossings, at Rock Creek and the Clark's Fork of the Yellowstone, also will be replaced with segments installed through direction drilling. That work is to be completed by next March, Moore said.
"Prior to completion of the new crossings, (Exxon Mobil) will monitor daily stream flow conditions and institute shut down and isolation procedures if flow conditions exceed agreed upon thresholds," Moore said in an emailed statement.
Cleanup of the spilled oil continues. Dozens of miles of riverbank were fouled by oil, and at the cleanup's peak more than 1,000 Exxon Mobil contractors were involved in removing contaminated vegetation and mopping up crude.
Only about 10 barrels of crude oil, or 420 gallons, were recovered, according to federal officials. Exxon Mobil and the DEQ are negotiating terms of the remaining work.
Silvertip is the main crude source for Exxon Mobil's 60,000-barrel a day refinery in Billings, which had been forced to scramble to find other sources of oil while the line was down.
The company in July estimated the spill could cost it more than $42 million, although that was only a preliminary figure and final costs could be higher after the cleanup proved more difficult than first expected.
The cause of the pipeline's failure remains under investigation.