* 345,000 bpd line shut after leak at pump station
* Quick restart expected
* Second Alberta spill in less than two weeks
CALGARY, Alberta, June 19 (Reuters) - Enbridge Inc on Tuesday closed a major Alberta pipeline that transports oil sands-derived crude after a spill at a pump station, the second oil leak to foul regions of the Canadian province in under two weeks.
Enbridge, Canada's second-largest pipeline company, said it was forced to turn off its 345,000 barrel-a-day Athabasca pipeline after an estimated 1,400 barrels of oil leaked from a piece of equipment at station near the northeast Alberta town of Elk Point on Monday.
It restarted the pipeline after shutting off the station, bypassing it and beginning cleanup, but closed it down again on Tuesday after the Alberta Energy Resources Conservation Board ordered it to do so, the firm said.
As a result, it expects to restart the line in days rather than weeks, company spokesman Graham White said. Enbridge is in discussions with the conservation board to determine when, it said.
The 540-km (335-mile) line carries oil to Hardisty, Alberta, from the tar sands center of Fort McMurray. Hardisty is a major pipeline hub from which crude gets fed into networks of export lines to the United States, such as Enbridge's mainline and TransCanada Corp's Keystone Pipeline.
Its capacity equals about 22 percent of Canada's 1.6 million barrels a day of oil sands production.
"No waterways are impacted and cleanup is under way. There were no injuries or no evacuations as a result of the release," the regulatory board said.
The incident follows an oil spill from a ruptured pipeline owned by Plains All American in western Alberta on June 7 in which cleanup with booms and skimmers continues. Up to 3,000 barrels of oil leaked into the Red Deer river system, fouling up a vacation resort area.
Environmentalists opposed to multibillion-dollar pipelines that are planned to take hundreds of thousands of barrels a day of Alberta crude to Texas and the Pacific Coast pounced on that spill as reason to reject the proposals.
"Once again Albertans are left to deal with the toxic effects of yet another pipeline spill in Alberta," said Mike Hudema, climate and energy campaigner for Greenpeace. "This latest spill comes from the company that wants to build mega-tar sands pipelines to both the East and West coasts, Enbridge."
There was only one resident in the area of the spill, Enbridge's White said.
A lengthy shutdown of the important regional line could force some oil developers to slow or halt production, depending on whether or not they have alternate transport for their crude or field storage tanks.
Canadian oil has already been deeply discounted for much of this year as production has climbed rapidly while export pipeline capacity has been tight. It is not known yet if cash crude prices will be affected by the incident.