Disclaimer: I do not have 85 Mining, and have never attempted to mine Runite. However, I've had many friends that do, and this is how they typically go about the activity. You'll want to wear dragonhide, if you can. If not, simply aim for the highest Magic defense stats you can obtain, as the spells are typically brutal. Pray against Range while running and hiding. In my Wilderness experiences, Revs will wait for you to return to a spot, so don't try to stick around for that final ore if you've been attacked on that world. Also, most people will go to the least crowded worlds to find Runite, since it would make sense that there are fewer people on that world to mine it. That's wrong. You want worlds with a middling population, and preferably at night.