[AlexanderHowl]

Twenty tons is not that difficult if you are careful (I had to participate in resupplies where we moved more than that in a few hours when I was in the Navy). The key thing is to limit the individual loads to around 20 lbs. If you assume that it takes four seconds to receive from the person to your right and give to the person to your left, you can move 18,000 lbs in an hour without an trouble. Over four hours, assuming two 30 minute breaks between three one hour sections of work, you can move 54,000 lbs before lunch.