Copper or bronze. Diameter 24mm, exactly the size of a Canadian quarter. Identical design on both sides. My thinking was that "B.C." stood for British Columbia, but I can find no evidence of any exposition that might have issued tokens. I also thought "Exposition" might have been the name of a town, but apparently not.
Not the first of these I have seen, but so far no solid origin. One thing I can say it's highly unlikely the B.C. stands for British Columbia. Most likely a merchant's initials. The token catalog website lists a few such pieces. http://tokencatalog.com/display_rec...=345&action=DisplayRecords&RecordsPerPage=100 5th to 7th coins from top of page.
Expo '86 was held in Vancouver, BC. Maybe if you searched that you might get lucky and find a similar token. Chris
For Galen59: "...Identical design on both sides." For cpm9ball: This token is far older than 1986; I would say, struck well before World War II. Keep trying.