TransCanada Corp. said it had received authorization from the Pipeline and Hazardous Materials Safety Administration (PHMSA) to restart the 590,000 barrel per day Keystone crude pipeline at reduced pressure Saturday.

The pipeline was shut down after a leak was discovered in an underground section in South Dakota last Saturday. The company initially told regulators that about 187 gallons of oil had spilled before the leak was controlled, but later revised its estimate to 16,800 gallons.

According to reports, Federal officials have approved re-starting the oil flow Saturday once the repair work on the key section of the pipeline was completed. About 100 yards of pipeline were uncovered from the four feet of soil covering it to find the leak.

However, it was not clear if the pipeline was restarted Saturday, Reuters reported.

According to Transcanada spokesperson Mark Cooper, no significant harm had come to the environment because of the leak. "The small amount of surface oil was contained using earth berms and absorbent material," Cooper said in an email Friday to the Associated Press. "There are no significant bodies of water nearby," he added.

Chances of ground water contamination are higher for pipelines that run underground as the Keystone pipeline does in South Dakota.

The company also said Saturday that it would conduct aerial and visual inspections at the site during the restart. The 3,000 mile-long pipeline delivers light and heavy crude oil from Hardisty, Alberta, to Cushing, Oklahoma and Illinois.