The C-130 transport aircraft's maximum payload is about twenty tons, and to transport sixty tons of gold, a single flight can carry a maximum of fifteen tons. This means that a total of four flights are needed to transport all the gold.
Aside from the weight, the range must also be considered. The C-130's maximum range is just 3,800 kilometers, and the flight from the U.S. Military's base airport in Djibouti to Pretoria in South Africa is 5,200 kilometers. Therefore, the C-130's range is far from sufficient, and it must be refueled in midair or land for refueling.
It's fine on the way there, since the aircraft is empty, but on the way back, the plane will be carrying thirty tons of gold, greatly increasing the burden of security during refueling.
Arranging for an escort is something Warfire Group is experienced in, so there's no need for Gao Guang to handle it.