The Transportation Department has given TransCanada Corp. permission to restart its Keystone oil pipeline, just a day after blocking resumption of operations on the line that has suffered two recent leaks.The department’s Pipeline and Hazardous Materials Safety Administration (PHMSA), in a letter Saturday, told the company that it had approved its restart plan and that the restart could commence today. “PHMSA’s decision follows a thorough evaluation of the company’s proposed plan, and safety activities required under the plan. As required by the Corrective Action Order, restart of the pipeline will be under restricted conditions and closely monitored by PHMSA,” the...