I think there is a strong case to be made for Kahnawake (or, alternatively, Mohawk or Haudenosaunee) Ironworkers to have their own category, rather than Canada, Ironworkers, which is very broad.
This is because there is a well-known interaction between the communities of Kahnawake and, to a lesser extent, Awkwesasne, in the ironworking industry of New York in the 1920s and 1930s. Some descendents of these ironworkers established the community of Little Caughnawaga in Brooklyn too, which may warrant its own category in the future.
Here is a link to a news article that prefaces this connection: How Mohawk ironworkers from Kahnawake helped build New York's skyline.