Posted by: Kever
I always thought the smallish rocks helped hold the gold together. I've seen "clean" gold turn to peanut butter in high traffic areas.
I don't use a sifter, so I always end up with some aggregate. I will hand sift when spreading the gold to get rid of the bigger rocks, sticks, pinecones, and any roots. Again, I am not doing this in high traffic areas, so my method will be different than say John Deere, or Expresso.
If you leave some small rock in, you don't have the peanut butter dirt issue at the start, but once packed, the clean gold will last longer (again, for high traffic areas). The peanut butter issue is when it is fresh work, you could see it happening a lot on the Fromme Climb Route as Peter was working this winter, but once it gets enough traffic it packs solid, unless there is water coming from the bedrock below (this did happen to him in a couple of spots).
I will use rock and gravel as a base in holes and low points, then layer gold over top, sort of like a paving base, I think it helps with allowing water to filter through.