I was with the wilderness crew for the US Bureau of mines out of Spokane. Our job was to fully understand the geology and mineral deposits within wilderness deposits of the 7 western states. It was all part of the wilderness act of 1964.
Besides some really interesting geochemical halos around the main deposit, it was the only place I have ever seen native gold in basalt that had bubbles in it.
Most of the reports were published or were placed in the archives in Denver. If you find a mine in a wilderness area in the west, the odds are one us had been there and wrote a report on it. I think the Salmon was done in the late 60s or very early 70s.