the ant hill from hell that WILL NOT DIE

the ant hill from hell that WILL NOT DIE

In my front yard there's a raised garden area surrounded by bricks, and in that area is a very large, deep ant hill. As far as I can tell, it's as deep as the entire raised garden area, and ants are living all along the height of it. I've been trying to kill them with amdro (a commercial ant poison) which has seemed to work for all of the other hills in our yard, but after 4 tries, the ants are still not dead. Is there another good way to kill them? I really want to get some weeding/garden maintenance done in that area, but I can't risk it with so many fire ants. Thanks in advance!
Help.  Plants Attack.

Help. Plants Attack.

Remember the mystery “weed”?

Remember the mystery “weed”?

my room.. finally

my room.. finally

My peace lilly wants to be special…

My peace lilly wants to be special…

Hawaiian Schefflera

Hawaiian Schefflera

Mystery To Me

Mystery To Me