Sounds like a good method. I think every inch of my yard has ants. I put spectracide on the mound then pour cold water until the mound flattens out, and that does destroy that location, but then they pop up nearby somewhere. Next time I will try boiling water LOL
My method:
1) buy can of Bengal
2) add red straw extender
3) put red straw into ant bed and spray until smoke comes out of ant bed
Bye bye ants