Combine the rosemary, parsley, garlic, oil, chives, mustard, salt and pepper in a food processor. Pulse until herbs are finely chopped and all ingredients are combined.
Coat the prime rib with herb mixture and refrigerate (uncovered) for four hours.
Prepare your grill for indirect cooking to 250°F.
Place the prime rib bone-side-down on the grill. Allow 15-20 minutes per pound, or until internal temperature of the thickest part of the prime rib reaches 120°F-130°F (rare to medium-rare).
Remove from grill, tent loosely with foil and allow to rest 15 minutes before slicing.