Controlling ants can be a hard issue to handle. Here are a few tips to get you started to get the hold on ant control.
First of all ants are monoculture, they do not like competition and so the key is to introduce a competitive force such as beneficial nematodes to attack the pupas of the ants.
By broadcasting dry molasses before you apply your nematodes you are actually providing a food source for the nematodes.
Attacking the fire mounds themselves it is my recommendation that you get flags to be able to check on your mounds as time goes by.
By adding 3 ounces of orange oil to 1 gal. of water and adding 1 ounce of liquid molasses you can drench the mound.
It is my recommendation that you get a long piece of half in rebar or wooden dole and drive it into the mound itself to create a funnel and pour the drenching mat. into the hole that was created.
The purpose is to get deep into the colony.