Border Patrol officials say the loads were discovered during unrelated searches at the Carrizo Springs Station.
Officials say a truck that appeared to be hauling large metal tanks included a hidden load of nearly 6 tons of marijuana. The other rig appeared to have a load of industrial lime sacks, but was concealing more than 3 1/2 tons of marijuana.
Authorities say the drivers, who are from Quinlan and San Diego, Texas, were arrested Saturday. Details of the busts were released Monday. Further information on the suspects was not immediately available.