I believe that The high amounts of sediments excavated now are caused after it was abandoned 9000 years ago. The reason why I belive this is because the structures are supposed to be 2 floors below ground making it sucessaptable to high sedimentation of dust and sand over time due to weathering of rocks and rain water rushing in from higher altitudes . I might be wrong but that is possible too. Nevertheless our theories conclude the same that they abandoned it later on. Perhaps the answer to the places lies in the trail they created after abandoning this place.
Also yes i agree that this was the place where homo erectus first started cultivating. After several thousand years.
I wish i could write everything I learnt about this place in one post. I probably can write a book on it. It's just mind boggling!
Also what do you mean by the hill is not a natural formation ?