The struggle to recover 30,000 gallons of oil from a pipeline spill into Montana's Yellowstone River is expected to grind to a near-halt in coming days as warmer weather makes ice on the river increasingly dangerous, state regulators and a company spokesman said Wednesday. Because of brittle ice, crews trying to recover oil trapped beneath the Yellowstone could be pulled off the river as early as Thursday, said Bonnie Lovelace with the Montana Department of Environmental Quality .