Minicon 4 was held in 17–19 June 1971 at the Curtis Hotel (Minneapolis). It was chaired by Jim Young and had a membership of about 150. Lin Carter was the guest of honor.
Lynn Torline, Secretary Marge Lessinger, Treasurer Ruth Burman, Operatic Productions Chuck holst, Film Coordinator Linda Lounsbury, Registration Jim Schumeister, Art Show Walk Schwartz, Huckster's Room Don Blyly Ken Fletcher Jim Odbert Blue Petal Lois Spooner Frank Stodolka Anthony Tollin Patt Worthington
Here it is in PDF (0.8 MB), or you can have one made out of the raw scans (72 MB), but probably you only want that one if you are on a fast connection and interested in the grain of the paper used. You can also see a text-only transcript (not counting advertisements). Finally, here are nice individual page images:
Here's a flyer advertising the convention. It's a photo of the original marker drawing of the flyer. We presume that the flyer ended up being reproduced and used, but that's just an assumption!