Major oil spill in Alberta likely caused by poor soil compaction

Calgary Herald : Last week Plains Midstream Canada’s Rainbow pipeline in northern Alberta ruptured, sending 28 000 barrels of oil onto the Canadian prairie. Although most of the oil has been contained near the rupture, some has leaked into nearby wetlands. The pipeline is owned and operated by Plains Midstream, a subsidiary of the Houston-based Plains All American Pipeline. On Friday, Stephen Bart of Plains Midstream told reporters that his company’s investigation into the spill had found the likely cause: Soil beneath the ruptured pipe had not been sufficiently compacted, causing the pipe to sag and experience stress. A badly welded joint was also a factor. Before the spill, the pipeline carried about 187 000 barrels of oil per day from Zama in northwestern Alberta south to Edmonton, 480 miles away.