Hey Kevin,
I have been working on a theory about Colorado gold. From my own experiences and learning from others, it seems to me that areas of Colorado that experienced glacial activity tend not to produce large course placers. We know the glaciers scour valleys clean of such deposits, and re-mix the gold in sediments. Which may indicate that the best places to search for gold placers in CO are where glaciation never occurred.
In the San Juan Mountains it seems most of the gold is still locked up in hard rock as well. Unlike the mountains in California, which are far older than the Rockies, erosional processes and earthquakes have not yet had the time to erode gold out of its matrix, where it can collect in placer formations.
All of which tends to make course gold placers in CO the exception, not the rule. Especially when compared to places like California or Alaska. Do you agree with these conclusions? And do you think CO prospectors would be better served by limiting their prospect areas to non-glaciated areas?