Pigs employed to clean oil pipeline

An aggressive cleaning tool called a disc pig was sent through the trans-Alaska oil pipeline over the weekend to find a stainless steel ring which broke off a previously used cleaning tool called a scraping pig. The cleaning tools removed wax buildup, enough to fill 11 55-gallon drums, but failed to find the missing part. The pipeline operator, Alyeska Pipeline Service Co, downplayed the risk of the missing ring, saying there is a low probability that the ring would interfere with a chec