Years ago I worked at the now closed Eagle Mt. Iron Mine for Kaiser steel. The ore would go from the pit to the crusher where the rock would be separated from the ore. From the crusher it went to the "pelletizing" plant where pure iron ore would be formed into pellets about the size of rabbit pellets. It was these pellets that were shipped to the steel mill in Fontana. A fully loaded ore car filled about 25% by volumn would be at the weight limit.