Hydraulic mining: How does the material get to the sluices?

[OwenT]

At a hydraulic mine, the material washes down with the water and flows through the sluices at the bottom of the pit. Simple I guess. I was just thinking this seems like it would only work if your sluice was on bedrock. Is that right? Any other way I see it, wherever you put the sluice, as the slurry runs into it it will also erode the material the sluice is sitting on and start going under the sluice instead of into it.

 

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[Bodfish Mike]

Is there really nothing left at all in California except flood gold? There must still be some virgin areas up in the most remote parts of the Sierras that they missed.

Yep it's all gone so don't waste your time looking and everyone else reading this you can also stop.

 

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[IMAUDIGGER]

Sometimes they were able to wash the material into the sluices.
Seem many photos of wheel barrow gang planks.
Many times the sluice was pretty crude and not easily cleaned up.

 

[IMAUDIGGER]

Few more..

 

[firebird]

Damn, that looks so inefficient. I wonder how much gold got thrown out into the pilings there or got stuck in between those logs and stayed there forever.

 

[IMAUDIGGER]

Damn, that looks so inefficient. I wonder how much gold got thrown out into the pilings there or got stuck in between those logs and stayed there forever.

When it comes to moving material it was pretty dang efficient compared to the alternative.
The excavation method broke up the material, washed the rocks clean, seperated the clays from the sand, AND moved the material.

They were happy with what they were getting given the effort involved.
You had to get it while the getting was good. There was always a new strike somewhere.

Because they were sluicing ancient channel material, it was usually full of clay. I’m sure the sluices packed up tight after a couple days running. Someone must have walked the sluices and raked the riffles.

 

[firebird]

Because they were sluicing ancient channel material, it was usually full of clay. I’m sure the sluices packed up tight after a couple days running. Someone must have walked the sluices and raked the riffles.

I've noticed that too in the areas I'm digging in, must be common in California placer deposits. On top I found lots of small flakes, then there was suddenly a thick nasty mucky layer of clay that was really hard to dig to but also had lots of rounded cobble rocks. I then dug it all up about a feet and found bigger flakes stuck in the clay. There was also then another layer of loser gravel beneath that clay layer that still had gold but now I can't dig into it anymore because the recent rains have completely flooded the area and it's underwater.

 

[OwenT]

Damn, that looks so inefficient. I wonder how much gold got thrown out into the pilings there or got stuck in between those logs and stayed there forever.

If by efficient you mean capture rate, then yea seems like it wouldn't be the maximum. One point I think though is that efficiency is getting the most for the least amount of work. They defenitely did that. A guy panning can get 100% of the gold but he sure won't get as much as even a small percentage of the gold in the thousands of yards run through those sluices. Like my finance teacher said. You can't buy things with returns (%), you buy them with money! (quantity)

 

[N-Lionberger]

If by efficient you mean capture rate, then yea seems like it wouldn't be the maximum. One point I think though is that efficiency is getting the most for the least amount of work. They defenitely did that. A guy panning can get 100% of the gold but he sure won't get as much as even a small percentage of the gold in the thousands of yards run through those sluices. Like my finance teacher said. You can't buy things with returns (%), you buy them with money! (quantity)

As I always understood it was the most efficient method available at the time and in a lot of situations around the world still is method of choice, its all about what the operator does with the slurry after it leaves the working face, the actual hydraulic method of blasting water through a nozzle at a bank of cemented gravel does a pretty fantastic job of slurrying. The efficiency of the sluices really depended on who set them up. They also sent so much dirt through their sluices that they could make profit with a few pennies worth per cubic yard.

 

[et1955]

A geologist told me this same thing in regards to where I live, that all of Maine was searched for gold, and if it was here, they would have found it. But my family has significant land holdings here, and was off limits. We were farmers and loggers. I got the diaries of my ancestors dating back to 1838, and I have yet to read anything about searching for gold. In fact, my Great Uncles went to California in 1849, and the swimming hole they swam in as kids here in Maine was where gold was discovered.

I am with you, I think virgin spots exist.

Here is a pic of a true virgin spot. This is a Catholic church built in 1885 in Sawyers Bar, Ca. Known as the richest ground for it was never mined. I will be going to my claim up river from this spot this summer.

 

[IMAUDIGGER]

Here is a pic of a true virgin spot.View attachment 1680698 This is a Catholic church built in 1885 in Sawyers Bar, Ca. Known as the richest ground for it was never mined. I will be going to my claim up river from this spot this summer.

It was actually built in 1855 (explaining why the ground wasn’t mined during the gold rush). There are graves dating all the way back to the early 1850’s.
Ever been inside? There is a large painting on the wall that was brought overseas by the monk back in the early days (at least there used to be).
That building will be just a pile of lumber soon. Needs a new roof badly.

Just read that it is allowed to be used under a Special Use Permit!
Imagine that..it was there 60 years prior to the National Forest and they permit its use.