TransCanada Corp’s ( TRP.TO ) 590,000-barrel-per-day Keystone crude oil pipeline continued operating at reduced rates, the company said in an e-mail on Monday, as an investigation into a leak earlier this month remained under way. A timeline for running the pipeline at full rates has not been set, according to company spokesman Mark Cooper. He added that that decision will be made in conjunction and with approval by the U.S. Pipeline and Hazardous Materials Safety Administration after the investigation and necessary follow-up actions are completed. “We’re beginning our root-cause investigation into the small leak and, along with that, we will undertake a fuller integrity investigation that will assure ourselves and our regulators that we have taken the necessary steps to reduce the likelihood […]