UPDATE 1-Enbridge restarts Alberta pipeline after oil spill

* Athabasca line flowing at about 280,000 bpd

* Impact on pricing minimal so far

CALGARY, Alberta, June 20 (Reuters) - Enbridge Inc restarted a major Alberta oil sands pipeline late on Tuesday, hours after regulators ordered it shut due to an oil spill at a pumping station in the latest incident to raise fears over pipeline safety in Canada.

Enbridge, whose lines carry the bulk of Canadian oil exports to the United States, said the failure of a piece of equipment on the Athabasca Pipeline caused more than 1,400 barrels of oil sands-derived crude to leak in a rural area.

The company said it was able to bypass the pumping station at Elk Point in northeastern Alberta. The pipeline was flowing at about 280,000 barrels per day on Wednesday, which is 65,000 bpd under capacity.

"Elk Point Station will remain on bypass until the site is cleaned, the terms of the return to work plan met, and the (Alberta Energy Resources Conservation Board) gives approval to restart the station," Enbridge spokesman Graham White said in an email.

The incident, the second leak from a pipeline system in Alberta in under two weeks, occurred as Enbridge seeks to build the C$5.5 billion ($5.4 billion) Northern Gateway pipeline to the Pacific Coast from Alberta amid opposition from environmentalists and some British Columbia native groups whose lands the line would cross.

A crude trading source said there was no immediate impact on prices for Canadian oil, due to the short duration of the outage and its timing between the three-week periods during which monthly crude deals are done.

However, it could have some impact if the line runs under capacity for a prolonged period, the source said.

Prices for heavy crude derived from Alberta's vast tar sands have been under pressure this year, partly due to a combination of surging production and tight export pipeline capacity.

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.