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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[N-Lionberger]

Some were on bedrock, some were carved out of bedrock while some simply sat on the ground, or raised above on trestles, the head often was fairly close to the working face but the sluice run could go on for hundreds of feet.

 

[IMAUDIGGER]

Some were on bedrock, some were carved out of bedrock while some simply sat on the ground, or raised above on trestles, the head often was fairly close to the working face but the sluice run could go on for hundreds of feet.

Looking at historical photos is the quickest way to get an idea.

I remember reading that lack of available fall was an issue that they had to contend with early on.

I suppose the difficulty was getting rid of the waste water/tailings. This was solved by running the tailings through tunnels if need be. I’ve seen photos of mines that ran their sluice boxes in the tunnels. Quite a few papers written on this method in the mining journals.

 

[Goldwasher]

Most often they would end up cutting trenches into the bedrock.

Or be right on it. adding sluice to the hungry end as they went.

When you read old journals you will often read mention of them "cutting races"

The would also end up having to cut tunnels or ditches to de water the low end of the "pit"

Also to get rid of tailings

 

[firebird]

It was such an inefficient process, but the only one they had available to mine full scale before excavators were created. You can find nuggets in hydraulic mining areas sometimes.

 

[Audozer]

It was such an inefficient process, but the only one they had available to mine full scale before excavators were created. You can find nuggets in hydraulic mining areas sometimes.

Exactly, I have found larger nuggets in areas that had been hydraulic mined and I know folks that have pulled quite a bit of gold from the piles of discarded host rock off to the side. In a lot of instances if the gold is still in the parent rock, it is entirely possible it could have rolled right off the end of the sluice. Not every miner knew how to do it efficiently back in the day.

 

[Bejay]

I personally know of one miner who cut/chiseled his riffles into the bedrock. He would go out after he did a wash/run and pick up the nuggets...his wife would go out with tweezers and pick up the fines/flakes. In the 50s/60s the USFS/BLM often came up to his workings and told him he was losing all his gold because he would wash boulders the size of cars down over his bedrock sluice. He had also built a dam way up the canyon and would trip it and divert the water towards the areas he wanted to wash away the mountainside. Last time I saw him was in 72 and I sat in his cabin and ate salt pork and beans with him. His name was Glen Young......an Oregon miner who fought and beat the USFS in court. Lots of stories can be told about Glen...he was 86 in 72 and his hair was as black as coal, and his big hands reminded me of old narley oak trees (they had been broke and busted so often). I wrote a short story about Glen and have often thought about getting it published...it got me a "A+" in Comp class. Sorry....the hydraulic mining got me a little off track thinking about him.


Bejay

 

[Bejay]

It was such an inefficient process, but the only one they had available to mine full scale before excavators were created. You can find nuggets in hydraulic mining areas sometimes.

I actually have a claim that was a hydraulic mine spot...….and on the bottom end of the creek, (where the stream flow is slack and deposition occurs) I find a lot of fine gold. I figured their hydraulic mining was inefficient to capture the fines. An occasional picker/nugget but not much. Lots of flour gold.

Bejay

 

[seafox]

Bejay please publish your storypeople who do should be remembered if only to remindnmaybe inspire those who come in the future. It was not inefficent when considering cost to production and miners math. A low cost sluice getting 99% of the say 2 tons of pay a day perman I'd a lotess than 70% of the gold in 10 or 40 yards/ tons of material per man day with the costly monitors flumes pipes

 

[IMAUDIGGER]

I actually have a claim that was a hydraulic mine spot...….and on the bottom end of the creek, (where the stream flow is slack and deposition occurs) I find a lot of fine gold. I figured their hydraulic mining was inefficient to capture the fines. An occasional picker/nugget but not much. Lots of flour gold.

Bejay

Being that it was a time consuming process to break the sluice box down to do a clean out, it was said that the bigger mines cleaned up only once or maybe twice a “season”.

Those old square nails probably didn’t pull out very easily.

 

[Goldwasher]

Being that it was a time consuming process to break the sluice box down to do a clean out, it was said that the bigger mines cleaned up only once or maybe twice a “season”.

Those old square nails probably didn’t pull out very easily.

The big ops used false bottoms and removable riffles. Small ops too. Breaking apart sluices for clean out was not a common thing?


Squre nails found at mining sights are from rotten gear. not tossed nails.

 

[seafox]

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.

The start of the slices were often placed where the topography narrowed in a gully and wing dams of dirt and rock funneled the slurry into the slice. Some distance between working face and slice was good as bigger rocks were thrown to the side ( Chinese stacked the rocks in neat rows walls. Others tossed them in loose piles. Since water did not flow under or through the wing dams pay travels where not carried by and lost. If between the working wall and slice pay gravel built a delta it increased the local grade and would tend to erode its self to more water would be directed there. Where the bedrock is favorable crevicing can be 10 or 20 times as productive as bar gravels but when you consider hundereds of acres washed to that sluice it was not inefficent recovery

 

[Goldwasher]

It was such an inefficient process, but the only one they had available to mine full scale before excavators were created. You can find nuggets in hydraulic mining areas sometimes.

It was actually a very efficient way to process. Most gold loss was on accident from trying to run with not enough water vs. too much.


Weekenders who don't find as much gold as they want to. Have come up wth all kinds of ampified myths as to why things made to capture gold don't

Even when thats not the reason.

The reason bigger gold can be found in pits today is that they didn't clean the bedrock as well as they should have. Not because it made it into and out of the sluice run.

Cobble with gold in it is a totally different thing.

 

[seafox]

One other thing read where one mine at least put the catch sluice into a tunnel to make guarding it before clean out easyer

 

[Goldwasher]

For a really good read on what the old timers during the Gold Rush used. When ,where, why and how.

Find a copy of

"The Elephant as they saw it"

 

[bug]

It was actually a very efficient way to process. Most gold loss was on accident from trying to run with not enough water vs. too much.


Weekenders who don't find as much gold as they want to. Have come up wth all kinds of ampified myths as to why things made to capture gold don't

Even when thats not the reason.

The reason bigger gold can be found in pits today is that they didn't clean the bedrock as well as they should have. Not because it made it into and out of the sluice run.

Cobble with gold in it is a totally different thing.

I agree these guys were very efficient. The crumbs that they left make us happy today, but you get into some of these areas and there is nothing left. We look for their mistakes, but even then, what are a few ounces or pounds compared to what they got.

 

[firebird]

I agree these guys were very efficient. The crumbs that they left make us happy today, but you get into some of these areas and there is nothing left. We look for their mistakes, but even then, what are a few ounces or pounds compared to what they got.

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.

 

[OreCart]

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.

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.

 

[N-Lionberger]

There are plenty of virgin spots. A lot of places weren't worked because of inability to convey enough water to the site.

 

[Goldwasher]

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.

no thats not the case. We're making.

But most times reworking their tailings is pointless. Certainly at large operations as most of them were running lesser grade material.

Many a big 1870'S and on era large mines wiped out smaller early period Gold Rush era mine.

Finding a real gold rush era dig that wasn't hit and wiped out later that has some good vigin ground.(exposed and ready to run) is a rarity.

It is however a mistake to think that they got it all. In my opinion especially at early sights.

In places like that tailings and throw out piles may be the only place you find bigger gold.

However depending on how rich the cround was there cam be great fine gold and mid to coarse. in between the Tom piles. Also the area where the small benches they worked meets the current and high water line. because that is where what did come out of their boxes has been reconcentrating.

Those little small claim smalll group pits surrounded by others of the same..sure must have been a muddy sloppy mess. perfect conditions to slop, spill, step on and mash gold into recently exposed bedrock.

ESPECIALLY ON SLATE!!

Could you imagine trying to detail bedrock that is constantly covered with mud cause your claim is only twenty by twenty feet if your lucky.

You have to scoot your tailings and new pay back and forth. using a wooden bucket if you have one. or commit to stacking it on the cheapest 1/4 of your claim.

oh then crap it starts raining.. for a week straight.

Their gear wasn't losing all that much gold. It was just a messy situation all around, condusive to leaving some gold undug or dropped.

As the the early guys made a lot more "mistakes" than the later guys.

Little side gulches, seasonal drainages that you have to hack and walk far to get to can be very good for small modern day prospectors.