Bucket Dredge Pics - 1940's to 1960's

[Au Seeker]

20 minutes ago, Morlock said:

I wonder how you would set up it up to dredge for ores of nobium, uranium and tantalum.

Those ores aren't particularly heavy compared to gold. Seems you'd have modify the process in order to capture those ores as opposed to gold.

Nobium is not that heavy, but tantalum and uranium are both pretty heavy, both much heaiver than lead and it can be caught pretty easy in a dredge, tantalum's specfic gravity is around 16.6, uranium is around 18.7, most anything with a specfic gravity of over 10 or 11 can be caught in a dredge pretty easy.

[Morlock]

7 minutes ago, Au Seeker said:

Nobium is not that heavy, but tantalum and uranium are both pretty heavy, both much heaiver than lead and it can be caught pretty easy in a dredge, tantalum's specfic gravity is around 16.6, uranium is around 18.7, most anything with a specfic gravity of over 10 or 11 can be caught in a dredge pretty easy.

While the metallic forms are heavy, I can't imagine those ores also being heavy. It just seems you wouldn't be able to run the dredge the exact same way for the ores as you would for gold.

[Au Seeker]

I agree there would have to be some modifications, water flow, riffle type, etc.,  but most blacksands caught in dredges easily only have a specific gravity of 5 to 6 as in the case of magnetite and hematite, and most all of these rare-earth minerals ore would be in the form around the size of sand, I'm sure not much of it was in big chucks, even when these dredges were dredging gold the material going through the sluices was screened down to no bigger than 3/4" to 1" and sometimes smaller depending on the gold being recovered.

[Saul R W]

Morlock, now you have me wondering how diamond dredges manage to separate relatively lightweight diamonds from heavier mud.  Maybe they're designed to catch the lightweight diamonds that wash over the top, and allow the heavy gunk out the bottom?  I'd never thought of that before, how to intentionally recover lighter target minerals.

[Au Seeker]

8 minutes ago, Saul R W said:

Morlock, now you have me wondering how diamond dredges manage to separate relatively lightweight diamonds from heavier mud.  Maybe they're designed to catch the lightweight diamonds that wash over the top, and allow the heavy gunk out the bottom?  I'd never thought of that before, how to intentionally recover lighter target minerals.

Diamonds, sapphires and many other precious stone or caught on a "greased" slick plate/table in which they readily stick to, diamond, etc. are hydrophobic, meaning they resist being wetted, and as such stick to a greased surface easily.

 

[Saul R W]

Aha!  That explains it.  Thanks.

[Morlock]

35 minutes ago, Au Seeker said:

Diamonds, sapphires and many other precious stone or caught on a "greased" slick plate/table in which they readily stick to, diamond, etc. are hydrophobic, meaning they resist being wetted, and as such stick to a greased surface easily.

 

http://www.greasetable.com

[IDdesertman]

Here's some serious equipment. Not sure of the location on this one...

[chrisski]

I wonder what it is?  Looks like something comes out the bottom and tailings go out the left...  Also can't tell if it is self propelled or towed...

[Saul R W]

18 hours ago, chrisski said:

I wonder what it is?  Looks like something comes out the bottom and tailings go out the left...  Also can't tell if it is self propelled or towed...

Perhaps a trommel?  If it is a trommel, though, I can't understand the reason for the huge Pitman arm.  Whatever it is, the axle/I-beam cross member that supports the track appears to be a temporary affair scabbed together just to get the contraption from one site to another.  It must have been towed by a Cat or winch. 

[Au Seeker]

20 hours ago, chrisski said:

I wonder what it is?  Looks like something comes out the bottom and tailings go out the left...  Also can't tell if it is self propelled or towed...

 

2 hours ago, Saul R W said:

Perhaps a trommel?  If it is a trommel, though, I can't understand the reason for the huge Pitman arm.  Whatever it is, the axle/I-beam cross member that supports the track appears to be a temporary affair scabbed together just to get the contraption from one site to another.  It must have been towed by a Cat or winch. 

The upper section is definitely a type of trommel, you can see the barrel shape of it at the top and also a drive motor at the right rear.

But what I can't seem to understand in that most trommels deposit the concentrates into a sluice, but I see no sluices, instead I see a possible centrifuge at the center bottom,

[IDdesertman]

Here's one more pic of the above contraption... found a note on the this slide that reads " Dredge near Sonoita, Arizona. June 1961".

[IDdesertman]

Here are a few pics of a different dredge. This one is the Natoma #6. Another article I read about it said that it was the last working dredge in California. Operated near Folsom, CA through 1962. These pics were taken July, 1959. 

[IDdesertman]

[chrisski]

On ‎5‎/‎15‎/‎2018 at 5:57 PM, IDdesertman said:

Here's one more pic of the above contraption... found a note on the this slide that reads " Dredge near Sonoita, Arizona. June 1961".

I wonder if this is similar to the dry land dredge that operated in the San Domingo Area? Never seen a picture of a dry land dredge.  Google does not have one.  There's Dry Blowers, but not a propelled drege.

[Rod]

A couple of pics that I took in Alaska

[Nugget Shooter]

Great photos, sets the mind to wandering..... Thanks.

[GeoJack]

Here is my trommel plate from the dredge in Snelling, CA. I have it set up for some ore, rocks and items found around our claim. Some interesting chisels are in the collection.

[clay]

On 5/20/2018 at 4:21 PM, chrisski said:

I wonder if this is similar to the dry land dredge that operated in the San Domingo Area? Never seen a picture of a dry land dredge.  Google does not have one.  There's Dry Blowers, but not a propelled drege.

The dredge used in San Domingo was the Geraldine dryland dredge manufactured by Yuba Industries and delivered in 1961. She was named after the owner of United Placers Industries, the company who ordered the dredge from Yuba Industries. The Geraldine was also used on the lower LSD west of the highway after mining on the upper LSD. There is some evidence she might have been used on the Hanson placer (still being mined) and  Malibu placer both just east of Hwy 60.

The Geraldine was much bigger than the processing equipment shown in that picture. The picture doesn't show the actual dredge. If you have ever been on the lower LSD those 40 foot cliffs along the wash were a result of the Geraldine dredging. Obviously not something the pictured machine could have mined or processed. The Geraldine was BIG.

Yuba industries is still manufacturing and rebuilding dredges when needed. Dredge 21 out of Marysville is retired now but Yuba Industries rebuilt Dredge 17 and is still actively dredging in California. About 7000 yards a day. They use it to test new mining equipment designs. I don't think there has been any point in California mining history when a dredge hasn't been operating on the major rivers since they were invented. Yuba Industries was the world leader in large dredge design and construction for nearly 100 years.

The older dryland dragline dredges were moved either by powered or passive tracks. Newer dryland dredges are the "walking" design and and the "feet" are retracted while the dredge is mining.

I've been trying to track down the Geraldine for years. Equipment of her size and quality doesn't just go away. I suspect a modified version of the original Geraldine is now working in White Oaks, New Mexico. The dragline/trommel they are using there looks big enough to be the Geraldine. It's hard to get a confirmation on that because private gold mining operations permitted as "sand and gravel" construction material mines aren't inclined to share their operating details with outsiders. If you have any doubt about that just try to get a statement from the Hanson "sand and gravel" operation at the mouth of San Domingo wash on Hwy 60. 😉

Edited May 22, 2018 by clay

[IDdesertman]

Thanks for that info Clay, I didn't have any details on that piece aside from what I already mentioned. 

Here's a few more... I like the old Willy's pickup in the background of the last pic. 

 

[AzNuggetBob]

3 hours ago, clay said:

It's hard to get a confirmation on that because private gold mining operations permitted as "sand and gravel" construction material mines aren't inclined to share their operating details with outsiders. If you have any doubt about that just try to get a statement from the Hanson "sand and gravel" operation at the mouth of San Domingo wash on Hwy 60. 😉

Great photo's guys.
Clay I worked for a private"sand and gravel" plant that provided sand for the Az. C.A.P. project. a lot of the work was contracted out. I was operating heavy equipment for them feeding the plant or loading trucks.  It was very successful operation but a lot of hard work getting permits and picking up and moving the whole plant from wash to wash as the project progressed toward phoenix. It was a pretty smooth operation except for those pesky nuggets that kept clogging up our power screens. just kidding about the nuggets, but there was a lot of byproduct in that sand and gravel. Im not saying the plant would be profitable as a stand alone operation for byproduct only but the sale of the sand and gravel more than covered the cost of the whole operation and we were loading trucks as fast as we could crank out the processed sand.
 AzNuggetBob

[IDdesertman]

Here's a few more. The first two pics are Yuba #21. Found this interesting info from the March 2003 article in the ICMJ:

Quote

"The Yuba #21 gold dredge sunk in the Yuba Goldfields of northern California in late January.The dredge is owned by Cal Sierra Development and was capable of processing 11,000 yards of material per day. The company has yet to determine why she sank.

The Yuba #21, profiled in the June 2002 issue of ICMJ, was 500 feet long and worth $15 million. She had undergone 2 years of renovation and was ready to get back to work when she mysteriously sank. Cal Sierra Development general manager Tony Massey said the company recently purchased the Yuba #18, the only other similar dredge of comparable size that was built in the 1930s. It will take a year for the company to receive the dredge, in parts, from its current location in Bolivia."

The last one is labeled "Trinity Dredge Co., Mary E. Smith Manager, 1912-1940." Found some info on historicalmarkerproject.com that states "The Trinity Dredge, operated by Mary E. Smith, was the richest, dredging over $2,700,000 in gold from areas now covered by Lewiston Lake."

[chrisski]

On ‎5‎/‎22‎/‎2018 at 11:46 AM, clay said:

The dredge used in San Domingo was the Geraldine dryland dredge manufactured by Yuba Industries and delivered in 1961. She was named after the owner of United Placers Industries, the company who ordered the dredge from Yuba Industries. The Geraldine was also used on the lower LSD west of the highway after mining on the upper LSD. There is some evidence she might have been used on the Hanson placer (still being mined) and  Malibu placer both just east of Hwy 60. 

 

Thanks Clay.  I had not found any info about that. You are a storehouse of mining knowledge. 😉

[clay]

On 5/22/2018 at 2:16 PM, IDdesertman said:

Thanks for that info Clay, I didn't have any details on that piece aside from what I already mentioned. 

Here's a few more... I like the old Willy's pickup in the background of the last pic. 

 

That's the Fairplay dredge delivered by Yuba Industries to the South Park Dredging Company just southeast of  Fairplay Colorado in 1941. If you have ever been there you know how large that lower dredge field became.

There were several smaller dredges running upstream of Fairplay, the best known being the much smaller Snowstorm dredge which is still mostly intact and in place except for it's long missing 12 yard walking dragline.

Edited May 24, 2018 by clay

[Saul R W]

This is such a great thread on a fascinating part of mining history.  Clay's encyclopedic mind is the perfect counterpart to IDdesertman's photo collection.  This is the first thread I look at for new posts whenever I sign in.