Exxon Mobil Corp. ’s Canadian subsidiary said Monday that it has shut down one of its largest oil sands operations for “several weeks” due to a problem in its core processing plant. Imperial Oil Ltd. said a vibration issue was detected at its Kearl oil sands mine’s core ore-crushing machinery, forcing it to suspend production that averaged 92,000 barrels of oil a day in the third quarter, excluding a 14-day maintenance window. “Installation of replacement parts is expected to take several weeks,” said Imperial spokesman Pius Rolheiser. “This work—early maintenance and repair to prevent longer-term issues—will have a near-term impact on Kearl production, but we believe it is the best approach to ensuring the safety and long-term integrity of the operation,” he said.