Feb 16, 2018:

https://www.washingtonpost.com/national/energy-environment/transcanadas-keystone-pipeline-spill-cleanup-on-schedule/2018/02/16/f430b03a-1357-11e8-a68c-e9374188170e_story.html

Nov 29, 2017:

The PHMSA said the Amherst oil spill was likely caused by construction/mechanical damage that occurred when that section of the pipeline was initially built in 2008. Further, the PHMSA said the damage was probably due to a weight that was installed in that section of the pipeline (used in areas where water might make a section of pipeline float).

The PHMSA also said that TransCanada received a special permit in 2007 allowing the company to operate the pipeline at a stress level of 80 percent of maximum, instead of the usual 72 percent.

The PHMSA is still investiating the spill.

Keystone Spill Likely Caused By Construction Damage, Investigators Say | NPR

PHMSA Corrective Action Order | phmsa.dot.gov

Nov 27, 2017:

Keystone pipeline to restart operations on Tuesday | The Hill

TransCanada to restart Keystone pipeline on Tuesday | Reuters

Nov 17, 2017:

Reuters reported that the Keystone spill of 5,000 barrels (210,000 gallons) ties the record for the largest U.S. oil spill in 2017.

TransCanada said it has contained the leak, that it was investigating the cause, and that the pipeline will remain shutdown until future approval for reopening from the U.S. Pipeline and Hazardous Materials Safety Administration (PHMSA).

Keystone pipeline spill pushes oil higher, fuels TransCanada opponents | Reuters

Nov 16, 2017:

TransCanada reported that the Keystone Pipeline spilled an estimated 210,000 gallons of oil near Amherst, South Dakota.

Brian Walsh, an environmental scientist manager at the South Dakota Department of Environment and Natural Resources, said there was a 5-hour time-lag from when TransCanada became aware of the spill until his department was notified. Walsh also said the area of the spill is a "flat, grassy area for grazing."

This pipeline is not the same pipeline as the Keystone XL Pipeline.

Keystone Pipeline Oil Spill Reported In South Dakota | NPR

Keystone pipeline leak spills 210,000 gallons of oil in South Dakota | CBS News