Old dredge and hydraulic workings

[IDAu]

I'm curious is anyone has some tips or some info that I haven't thought of. I recently got an 100 acre placer claim in on of the richest sections of the state. The valley is lined with old bucket dredge tailings.

Several local guys were excited about it, with one joking that he would give me $10k if I didn't want it. After a month of working hard sampling I'm wondering if it's been worked dry. An out of state friend said if it's been hydraulically mined, good luck. I'm starting to think he's right. I keep hearing that the old timers only got 30-40% of the gold, but it's sure looking like they got more like 90%+. If they dredged the hell out of it then hydraulically mined the sides of both sides to bedrock I'm wondering if I'm wasting my time. Old pictures make it look like they turned it into a moonscape at the beginning of the 20th century.

I keep hearing how great tailings piles are for detecting but I have not even found the tinniest picker. The piles, the long stretches of old ground sluice...nothing. From my understanding of the dredge, it seems unlikely that gold made it into any of the bigger rock piles, unless it was a massive nugget. If the conveyer took large oversized rocks that were washed and spit them out I can't imagine any smaller gold made it in those. I've dug down in them (bigger rock piles in winrows) after moving a ton of rock and didn't find any color sample panning.

I've ran my high banker on several of the smaller (1-3") rock piles. A few small pickers, but still only 0.1-0.15g an hour. And I have a huge high banker that can handle shoveling as fast as I can into it.

I've tried finding the edges of the dredge workings and dug down into the hillsides. Little to no color. Again, if they used hydraulic mining, am I wasting my time?

I've dredged to bedrock on a bend. Best day was 0.33g.


The gold is not increasing with depth. In fact, I seem to find tiny pickers in the first 1-3' and smaller gold towards the bottom.

So far nothing is even worth the gas and certainly not worth the hard labor. Should I move on, or is there something I'm missing about mining old workings?

 

[tamrock]

Sounds like the best possible way to make it pay in the past was to move large volumes of material with a bucket line dredge, which more than likely recovered a good portion of the easy pickings. I would say with that, its probably pretty well played out. Kinda sucks the old timers cleaned up in the blink of a geological time frame on most every deposit of concentrated placer gold which took tens of thousands of years to accumulate.

 

[russau]

If it were me , I'd check into some research (if possible )into the particular bucket line dredge set up that worked that area . Most of these had a 3/4 classification in their trommel and the bigger pieces went out to the tailings pile. I know it would be a 1 in a million chance to find "that nugget " BUT you have that opportunity at your disposal right now . I'd also check into what type of equipment could find gold under those piles of waste rock . Yep I'm sure they would be expensive BUT on the other hand gold is at a high value . Maybe hire a guy /company that already has this equipment and pay to have them teach you to use it BEFORE buying one ? Well it was just a thought ! Good luck on your decision ! XRF comes to mind !

 

[Jim in Idaho]

Were it me, I'd buy a Nexus deep detector and work it for really large specimen gold....the stuff that was just put over the grizzly and out. The mid-size gold is gone...that's what was targeted....waste of time and effort looking for that.
Jim

 

[IDAu]

I am amazed at how much of the small stuff they got.

What I don’t understand is why the stacks are mostly clean large boulders. If everything exited the trommel that was above three-quarter inch why isn’t there smaller rocks mixed in?



Sounds like this claim is probably best left for playing around for a “one in 1 million lifetime find” later on. Not for running material now.


This is from an hour test run on what I thought was a “clean out pile”

 

[arizau]

I

I am amazed at how much of the small stuff they got.

What I don’t understand is why the stacks are mostly clean large boulders. If everything exited the trommel that was above three-quarter inch why isn’t there smaller rocks mixed in?



Sounds like this claim is probably best left for playing around for a “one in 1 million lifetime find” later on. Not for running material now.


This is from an hour test run on what I thought was a “clean out pile”

It makes sense to me that the coarse tails were conveyed and stacked on top of settled sluice tails at the back end of the pond as the dredge advanced. So what you may have is coarse bulk waste on top of fine sluice waste on top of bedrock with maybe some areas of virgin ground.
Good luck.

 

[Johnnybravo300]

Sounds like Cache Creek here in Colorado.
After it was hydrauliked you either find nothing or the biggest pieces of the year.
It took awhile for me to figure it out there.

 

[tamrock]

Sounds like Cache Creek here in Colorado.
After it was hydrauliked you either find nothing or the biggest pieces of the year.
It took awhile for me to figure it out there.

Back when I lived in Buena Vista around 1981-82 there was this young fella that come in the Lariat bar every now and then for a few beers. He was camping up around Cache Creek and mining what gold he could. He told me he could make $5 to $7 bucks a day in gold. He said he was determined to live off the gold he could find. Not sure how long he was able to hang on, because eventually he quit coming in the bar.

 

[Tesorodeoro]

Can you post a couple photos of what you think are bucket dredge piles? Below is what the 1930’s large scale bucket dredge tailings look like around here.

Pre WW1 dredger tailings, likely re-mined later. Tailings were dumped behind the dredge and the bucket line rotated as they mined forward.

You never see large boulders in the bucket line tailings, I suspect they went around them since they were working in the blind.

There were what was called a “Doodle Bug Dredge” that was used earlier than 1900. It was a small operation, where they would hand dig a hole and drag the dredge into it. A ditch would convey water to the hole and float the dredge. It could then dig its mining pond and start forward. You can imagine the muddy water they ran through their boxes. You don’t typically see the symmetric tailing piles from this type of early bucket dredge,

 

[Tesorodeoro]

My point being, mining efforts repeated based on industrial advancements. A creek could have been mined by picking the bedrock cracks, then with a pan, then a rocker box, then hand mined with a large crew, then wing dammed, then dredged with a doodle bug, then a large scale bucket line worked it bank to bank top to bottom. That’s how very rich ground was mined over the course of 100 years.

Some rich ground was ground sluiced and they walked away from for whatever reason, leaving rich ground buried 12-20 feet deep.

An example being a home site or an uncooperative claim or water right holder, or a war. Lots of reasons for rich ground being un-mined.

 

[Johnnybravo300]

Back when I lived in Buena Vista around 1981-82 there was this young fella that come in the Lariat bar every now and then for a few beers. He was camping up around Cache Creek and mining what gold he could. He told me he could make $5 to $7 bucks a day in gold. He said he was determined to live off the gold he could find. Not sure how long he was able to hang on, because eventually he quit coming in the bar.

There are still guys that try that and get caught staying all summer haha. I know one myself.
A few years ago my wife and I spent the day there and we met a scruffy guy that said he'd never be caught or found out there, he was so well hidden.
He found 8 or 9 really nice pickers on his bday and he wanted to trade a few for some edibles I had and I said sure.
Not much has changed there. Every weekend is a party and it can be a busy place but there is still alot of nice gold under those tailings.

 

[IDAu]

My point being, mining efforts repeated based on industrial advancements. A creek could have been mined by picking the bedrock cracks, then with a pan, then a rocker box, then hand mined with a large crew, then wing dammed, then dredged with a doodle bug, then a large scale bucket line worked it bank to bank top to bottom. That’s how very rich ground was mined over the course of 100 years.

Some rich ground was ground sluiced and they walked away from for whatever reason, leaving rich ground buried 12-20 feet deep.

An example being a home site or an uncooperative claim or water right holder, or a war. Lots of reasons for rich ground being un-mined.

Dang just got home I should have grabbed some better pics.

I’m sure it was reworked a couple times like you mentioned. The large boulder stacks aren’t what I was talking about. Those are more like several feet across, and in neat stacks piling up 30’ high or more. Not sure if that was from the doodle bug or some old timer crane. There are a handful of long rows that another claim owner told me came straight off the dredge that way. They are about 6-12” rocks in neat rows.



I found a really old rocker box/Slo maybe from the 80s? It was on a bench with hard pack gravel. It looks like he did a lot of work. But sampling in the hard pack resulted in the same thing I get from literally every other sample on the claim. 2 to 3 small colors. I don’t know what he was working. It seems like no matter what pile or where I dig down to bedrock on the sides it’s always the same grade.

This is what I dug for a measly 0.25g. 3 hours of hard digging. I washed all of the cobbles I circled for it. If I had more of these small rock piles, I might be able to justify some equipment. Maybe the ground in Idaho just sucks. Several different people have said what I got isn't bad. Not bad for someone with an excavator and plant running 50+ yards a day maybe... I think we have different definitions of "good ground." I made like $6/hr, without set up, and it didn't even cover gas. That's not good lol.

 

[Tesorodeoro]

If you find any old punch plate, it might give you an idea of what they thought they should be processing. Large holes might mean they thought the chances vs were high of finding a nugget that would fit through the hole.

You could find some native ground that was buried with tailings or a nugget that would fit through the punch plate, lots of labor running tailings.

 

[tamrock]

There are still guys that try that and get caught staying all summer haha. I know one myself.
A few years ago my wife and I spent the day there and we met a scruffy guy that said he'd never be caught or found out there, he was so well hidden.
He found 8 or 9 really nice pickers on his bday and he wanted to trade a few for some edibles I had and I said sure.
Not much has changed there. Every weekend is a party and it can be a busy place but there is still alot of nice gold under those tailings.

I can imagine with the price of gold these days. There's been a few industrial size placer options start up within the last 5 or 6 around Fairplay and Alma. Also one in Lake County. Gold wasn't that much, when I lived in the upper Arkansas Valley and I hardly ever saw another soul when I was out sampling the banks of the river.

 

[IDAu]

If you find any old punch plate, it might give you an idea of what they thought they should be processing. Large holes might mean they thought the chances vs were high of finding a nugget that would fit through the hole.

You could find some native ground that was buried with tailings or a nugget that would fit through the punch plate, lots of labor running tailings.

I’ve heard either 3/8 or 3/4.

Sounds like this claim is more for a hobby looking for a rare nugget and I’m looking for material to run for income. Time to move on ☹️

 

[Tesorodeoro]

I’ve heard either 3/8 or 3/4.

Sounds like this claim is more for a hobby looking for a rare nugget and I’m looking for material to run for income. Time to move on ☹️

Well if processing tailings, you would need at the min. A mini excavator and a trommel. Any ground they missed would be either under water, covered in tailings, OR a side draw or bench along the edges of the creek. The latter is what I would be looking for.

 

[IDAu]

Well if processing tailings, you would need at the min. A mini excavator and a trommel. Any ground they missed would be either under water, covered in tailings, OR a side draw or bench along the edges of the creek. The latter is what I would be looking for.

That was the plan. Use the high Banker to test the ground before justifying a wash plant and getting equipment up here.

But so far, I don’t see any material worth doing that. At least not in enough volume. I would need some huge equipment to move the larger piles to get underneath

With all the hydraulic Mining they did, I think it’s gonna be pretty hard to find any decent benches they missed.

 

[Tesorodeoro]

That was the plan. Use the high Banker to test the ground before justifying a wash plant and getting equipment up here.

But so far, I don’t see any material worth doing that. At least not in enough volume. I would need some huge equipment to move the larger piles to get underneath

With all the hydraulic Mining they did, I think it’s gonna be pretty hard to find any decent benches they missed.

If you are located near any agriculture land, it’s possible there is older aerial photos that possibly could shed light on what was going on when.

I went down to our USDA Farm Bureau Office and was able to find some 1927 flights they did.

The USFS may also have some drawers of aerial photos.

I’ve found some great ground that the old timers literally mined past.

I think it’s fairly easy to get a permit for a test hole as long as the tailings are washed back into the hole and reclaimed before a new hole is developed. I’m thinking an extend-a-hoe. A person might rent a backhoe for a week and find something to get interested about. Or they may end up just walking away with experience.