Reuters: An Exxon Mobil pipeline spill into the Yellowstone River in 2011 would have been far less severe if the company had not delayed closing valves, a report issued on Wednesday by federal pipeline regulators said. Exxon's Silvertip pipeline, which carries 40,000 barrels per day of crude in Montana, leaked about 1,500 barrels of oil into the Yellowstone River in July 2011 after the region suffered heavy flooding. Had Exxon Mobil Pipeline Company's shutdown procedures required remote controlled valves...