According to the Associated Press, the initial cleanup along the oil-fouled Yellowstone River could be tested Tuesday as rising waters make it harder for Exxon Mobil Corp. to get to areas damaged by the crude spilled from a company pipeline. The National Weather Service predicts the Yellowstone River, swelling with mountain snowmelt amid hot summer temperatures, will peak at Billings on Tuesday afternoon — a day after Exxon Mobil Pipeline Co. President Gary Pruessing promised to do whatever is necessary to mop up oil spilled from the duct at the river bottom. That pledge included sending crews to walk the river banks in search of pooled oil once the flooding river recedes. The 12-inch pipeline burst Friday upstream from a refinery in Billings, where it delivered 40,000 barrels of oil a day. Up to 1,000 barrels, or 42,000 gallons, of crude oil oozed into Yellowstone before the leak was stopped. Exxon Mobil acknowledged that the scope of the leak could extend far beyond a 10-mile stretch of the river. The 20-year-old Silvertip pipeline followed a route that passes beneath the river. It was temporarily shut down in May after Laurel officials raised concerns that it could be at risk as the Yellowstone started to rise. Also twice in the last year, regulators warned Exxon Mobil of several safety violations along the line. The company decided to restart the line after examining its safety record and deciding it was safe.