Bicep injuries in strongman are usually without exception always caused by prolonged wear and tear. Most common cases are related to guys using PED's with higher work load capacities crossing paths with a heavy stone, sandbag, or strapless axle deadlift.
Also, MotherRucker and his invaluable advice taken from one of the best american strongmen to grace the sport, is totally right in that you cannot perform an efficient stone load without using your biceps. The key is to keep a very prudent watch on your recovery and how you devise your training. So with that you shouldn't have a heavy burden of a possible bicep tear. As long as you're taking preventative measures, you will be just fine.