UPDATE 3-Enbridge says Alberta pipelines still shut after spill
* Southern portion of Athabasca pipeline returned to service
* Spectra Energy says 280,000 bpd Express-Platte line restarted
* Suncor cuts output from Fort McMurray operations
June 24 (Reuters) - Major Canadian oil pipelines that move almost 1 million barrels per day (bpd) of Alberta oil sands crude remained shut on Monday, after a spill on a smaller line was discovered on the weekend, operator Enbridge Inc said.
Enbridge, Canada's largest pipeline company, said on Saturday that 750 barrels of synthetic oil had spilled from the 17-km (11-mile) Line 37, which serves CNOOC Ltd's Long Lake oil sands project in northern Alberta. The rupture was spotted about 70 km (43 miles) southeast of the city of Fort McMurray.
The spill, which may have been caused by heavy flooding that has paralyzed the Alberta city of Calgary, headquarters of Canada's oil and gas industry, forced Enbridge to shut two much larger lines as a precaution, threatening a serious disruption in the flow of oil sands crude.
The 345,000 bpd Athabasca pipeline, which carries dilbit blended crude to the Hardisty terminal in Alberta, and the Waupisoo line, which can carry up to 600,000 bpd depending on crude viscosity, to Edmonton, Alberta, were both shut.
Those are two of the biggest lines that carry crude from the northern production centers around Fort McMurray to the storage and pipeline hub in Hardisty, Alberta, connecting to Enbridge's main export pipeline that runs into the United States.
Enbridge returned a section of the Athabasca pipeline between Cheecham, south of Fort McMurray, and Hardisty late Sunday. Continued...