HELL or not HELL?

[OakTree500]

My understanding is that it's an embellishment of a known place: IE if you sin you'll be thrown into the city dump (Gehenna) to burn for all eternity, with burning relating to the fires constantly burning in that place. It's an actual threat of some kind "Do this and you'll go to a place you actually know about" with a supernatural twist "...and burn forever".

Again, the point ultimately is it's the bible and everything there-in is bullshit anyway, but you get the point.

Is there a primary source I can access that states Gehenna was a city dump?

Rational wiki states it was the equivalent of the city dump for Jerusalem, but I can't find anything to confirm that.