 The head of 3M announced Tuesday that poor returns this past year means the U.S.-based company will cut 2,500 manufacturing jobs, but hasnt yet provided details on whether Canadian workers will be impacted. 3Ms Canadian headquarters are in London, Ont., as is the countrys largest manufacturing plant, where products such as Duct Tape and sandpaper are made. 3M ... 3M to cut 2,500 jobs, no word if workers at Ontario, Quebec,... 