PENDLETON, OR - A century-old farmhouse near Pendleton has been demolished to allow workers to continue cleaning up almost 5,000 gallons of diesel fuel spilled in an accident in March.Two excavators on Tuesday tore down the Hill Ranches farmhouse. It was built in 1905 and most recently had been used by a ranch hand's family.A semitrailer truck crashed nearby along Highway 37 in March, hurtling its trailer into a ditch, spilling its load of fuel. Crews have since been digging contaminated soil from a growing gully. A State Department of Environmental Quality spokesman says experts don't know how much more digging will be required. He says cleanup costs are likely to exceed $1 million.