Pressure restrictions on TransCanada Corp’s Keystone oil pipeline were lifted on Tuesday in a letter issued by U.S. pipeline safety regulators, a spokesman for the agency told Reuters on Thursday. It was not immediately clear what current flow rates are, said Darius Kirkwood, a spokesman for the U.S. Pipeline and Hazardous Materials Safety Administration (PHMSA). The company in November shut down its 590,000-barrel-per-day Keystone pipeline, which links Alberta’s oil sands to U.S. refineries, after a spill in South Dakota and was ordered later that month to operate at reduced pressure. Reduced flows on the pipeline had helped draw down inventories in the Cushing, Oklahoma, storage hub. A return to full capacity on the line is also expected to help relieve a bottleneck in the oil-producing province of Alberta, where increased output has run […]