The Globe and Mail reports in its Friday edition that Trans Mountain Corp. asked the Canada Energy Regulator on Thursday to reverse a decision rejecting proposed construction changes on its oil pipeline expansion. A Reuters dispatch to The Globe reports if Trans Mountain goes ahead with the construction plan that is currently approved, complications could result in a borehole becoming compromised, forcing Trans Mountain to find an alternative installation plan. The CER this month had denied Trans Mountain's request for a variance on a section of pipeline under construction in British Columbia. Trans Mountain had asked to be allowed to install smaller diameter pipe in a 2.3-kilometre section of the oil pipeline's route after encountering difficult drilling conditions owing to the hardness of the rock in a mountainous area between Hope and Chilliwack. The CER decision was yet another setback for the expansion project. In Thursday's letter, Trans Mountain said the hard rock conditions and fractured areas within the bedrock have allowed high rates of water ingress, causing complications. Those problems are likely to worsen if Trans Mountain has to proceed with installing larger-diameter pipe, it said.