So sorry to hear that you have been taking 20 years in your...

So sorry to hear that you have been taking 20 years in your geology degree course. I sincerely hope you are in final year at least after all this time. Must be painful but keep plugging on and you should eventually get through.
What does copper do to iron? You should have done that in first year . Copper in fact helps the corrosion resistance of steel and also prevents rusting. If you spend a bit more time studying instead of wasting your time chatting here with your good old buddies (gobs), you would know that magnetite is extremely magnetic. Copper is not. The two can be separated by magnetic separation after milling. It is a shame you do not know after 20 years of studying that copper is not magnetic. Please don't continue to waste your time here wondering about separation of other metals. Go check your books. Or better still, ask your gob mates. Hopefully you will at least acknowledge the fact that getting 85M of (more than) 80% magnetite in a drill hole is extremely good.
Good luck with your studies.