I wonder how long the place has been a dump.
If its been a dump for hundreds of years, the layers and layers of refuse would provide the perfect protection for the site as civilization and industry grew all around it.
An unintentional protector for the treasure underneath.
You know, I don't know. This story, though, is really a year old. There are lots of hits on Google for the name of the institute that is doing the research, from November of last year. Here's a photo of the skull in question:
