I've a couples of ideas, in case you've not already thought
of these:

1.  Richard V. Francaviglia's HARD PLACES.  Published by U
of Iowa Press, 1991

2.  Larry Kingsbury, Forest Archaeologist on the Payette NF
in McCall, Idaho.  There are lots of placer mining sites on
that forest, including remnants of Chinese workings, ditches
galore, housing, cemeteries, roads, trails, dredges, and
just about anything your heart desires from 1860-present.

Good luck!

Lee Bennett
Bennett Management Services, LLC
Monticello, Utah