TransCanada voluntarily shut down the pipeline on 29 May 2011 after an above-ground incident at a pump station in Kansas involving less than 10 bbl of oil.
The pipeline will be monitored closely in the coming days to ensure it is functioning appropriately.
Flows will be gradually ramped up in the coming days and TransCanada will be able to move all volumes nominated by its customers for the month of June.
The Keystone Pipeline System is comprised of the 3,461 km Keystone Pipeline and the proposed 2,673 km Keystone Gulf Coast Expansion Project (Keystone XL), which will start in Hardisty, Alberta, in Canada, extend southeast through Saskatchewan, Montana, South Dakota and Nebraska and end in Cushing, Oklahoma, in the US.