No desire to start with a wealth community. Just small-scale manufacturing and equipment. The scope of industry I'm thinking for the M.C is intact pneumatic and electric cabling equipment. There wouldn't be communications infrastructure nor electrical grid. All the fuel goes to the city, or what little is left anyhow. The city can grind out some makeshift mechanical tools for repairing what's laying around. Mining is the key word. Scale down the current operation and we're thinking medieval mining. The tools left around or cobbled together amplify the output, but there isn't much to pass around. Automobile parts and mechanical repair tools get sold to other communities, exchanges are had. 

Bare minimum equipment needed to maintain mid-19th century mining, and a very small labor force to begin with. Again, the villages around Marquette are hilariously dependent on that city. What little they can afford to sell they do. I'm operating under the assumption that all heating and electrical utilities are gone from the surrounding area, including Marquette. When someone can provide you with leftover tools, however crappy they are, that can mean quite a difference. The goal of Marquette is expansion exactly because they are self-aware of their predicament. The M.C isn't wealthy, it's just a fortified hermit government operating on long-term food rationing. Uniting the U.P will ease the pain, but the real bounty lies south.

(I'm attending Western, definitely aware of the size difference. NMU however is still the biggest campus in the region. Training Electricians and Technicians takes equipment, lots of it. The equipment doesn't even matter, it's the textbooks and knowledge they can scavenge.)