Set oven to 400 degrees.
Drizzle oil over prime rib and rub to coat lightly.
Rub with spice rub and place in a roasting pan.
Place roast in the oven and cook for 20 minutes, until browned.
Reduce the oven to 275 degrees and continue to cook, basting occasionally, until an instant-read thermometer inserted into the thickest part of the meat registers 120 degrees (for medium-rare).
Remove from oven and loosely tent with aluminum foil.
Let rest for 20-30 minutes before carving.