our landfill/waste companies have a specific routine and method in which they dump waste. This may true of this landfill.
Tuesday it may be dumped in "pile" A, wednesday it may be dumped in pile B etc and so on.
IMO This specific piece of evidence, will be located in an area where trash from many places on the truck's route was dumped.
All that garbage in the same general "layer" of the pile will likely be from garbage that was thrown out during the same time period as the piece of evidence they seek. Much of that garbage will be receipts, newspapers, etc that will offer a clue to the date/time period it was dumped.
Conceivably, "joe blow's" garbage located near this evidence could very well nail down the timeline.
Also, if they have info or tip that EB or AB made the dump run themselves and the evidence did not come there in a garbage truck, it is probable that for liability reasons, individuals who dump there are directed to a separate area, that is not being dumped in by the large trucks or being moved around by heavy equipment.