ottawa dec 1 reuters  formal talks between canada and the united states over a disputed michigan pipeline should start soon ottawa said on wednesday the latest development in an affair souring bilateral relations last month canada invoked a 1977 treaty with the united states to trigger negotiations over enbridge incs enbto line 5 which michigan wants to shut down on environmental grounds l1n2r02aa michigans governor said on tuesday she would dismiss her lawsuit against the pipeline in federal court clearing the way for a separate case in state court canadas foreign ministry said the move did not affect talks under the 1977 treaty read more we expect the formal negotiations to begin soon ministry spokeswoman clara trudeau said by email noting that canada has consistently supported the continued safe operation of line 5 and raised it with the us government at every level the treaty has never been invoked before line 5 ships 540000 barrels per day of crude and refined products from superior wisconsin to sarnia ontario michigan ordered it shut down by may over worries a leak could develop in a fourmile section running beneath the straits of mackinac in the great lakes enbridge ignored michigans order and the sides are embroiled in a legal battle canadas federal trade minister mary ng is due to raise the matter during three days of talks in washington this week her office said she will also discuss irritants such as us duties on canadian software lumber and planned us tax breaks for domestically produced electric vehicles