I said it could have been plausable. The pictures tell a different story. The piles being dumped in the pics. and the gravel plant are both farther up river than the piles near Chinamens placer area.
There are hundreds of medium to large mining ops that never got recorded and if you see the same name in an area several times it usually means that there as one location and several people put it on paper and then into the later record incorrectly because the sites are gone and hard to find once in the field. The links that get shared verify that constantl;y...most google earth layers do it consistantly antone ho uses mindat and usgs sources sees it a lot. Minecache is terrible about it.
If you compare the more recent field surveys performed by USGS to help close and make safe abandoned mines ith historical record the ne USGS surveys are missing more than fifty percent of the originally named mines. There are three hundred knon mines listed in the three mile radius around my house. locating fifty of them is very difficult for those three hundred knon there are probably double that in prospects and surface digs that never had a name.
In a river basin full of gravel and open space the engineers definetely didn't have to source gravel or fill and they didn't have to travel far to get dredged material out of the area. In the construction photos of the dam site (The pic is labled Priest Rapids keep that in mind a rapid doesnt keep its name three miles distant) you can see them lining the piles in straight lines..it is eather for a temporary earth coffer dam or part of the dam on the northern shore. looks like the area that has modular homes presently is close to those piles in the pic.
That is a placered area. There seems to be some impliment in the google earth image close to the orchard that is there...any idea hat that is? You can also see that some of the piles have been semi leveled closer to the farming area.
A historic photo predating the dam could help a lot. In the 1964 image those piles had been there for years predating the dam. The date O.t. gave as 30's-40's I suspect it as called Chinamens Bar long before the 30's and 40's
I kno Chrls thinks im just arguing none of my logical points and picture angles have been soundly disproved because they cant be. Boots on the ground should clear it up even more my points are pretty logical I hope they help.
P.s. My double u key is broke lol....and cue...its amazingly difficult to put all letters in to groups and not have those 2 letters if you could imagine