Minnesota-based Mayo Clinic has announced that it plans an outpost at the Mall of America as the mall expands into a second phase. Mayo officials said they haven't decided what services the site will offer, but said they could include diagnostic screenings, wellness counseling and other services that might direct patients to the home campus in Rochester. At a news conference, Mayo executives said they plan to spend the next 12 months deciding the nature of the facility and the size of their investment.