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geowizard
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Re: Fine Gold Sluice Design Help Needed ( 01:01:22 FriFeb 17 2017 )

Fleng,

You said...

"Not sure if drilling mud is actually needed for dragline's system."

The fact is that MUD may be the solution to the elutriation of gold in the drill stem!

Here's a reference to a Mud company known as Baroid:

http://www.baroididp.com/idp/resources/technical-assistance/fluid-testing/viscosity.page?node-id=hm8zxvp8

Viscosity is a major player in the lift that is responsible for lifting gold UP vertically.

Certain mud additives like "gels" can give the lift needed to make the difference between success and failure.

There are some important concepts here that offset the factors that could be show stoppers.

The right mud will lift the GOLD. :smile:

- Geowizard

  
Fleng
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Re: Fine Gold Sluice Design Help Needed ( 17:42:35 FriFeb 17 2017 )

Would an additive improve performance of dragline's system? Of course. If you pumped mercury in with the water I could see a very significant improvement in yield. Being facetious here :smile:

Getting an approvable mining plan with minimal environmental impact is what it is about. The material safety sheets were not supplied in the link. Cost and recoverablility would factor in. Not saying it isn't a good option just that it adds another level of overhead to the test process.

My question is that of diminishing returns. Washing fine sand in a gravity sluice is cheap and clean. I doubt that dragline's intention is to go down further than several feet at any one location. In rocky terrain, with a high specific gravity a mud gel might be helpful.

  
geowizard
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Re: Fine Gold Sluice Design Help Needed ( 19:26:46 FriFeb 17 2017 )


From what dragline said, he wants to go down 10 to 20 feet.

So, if the suction drill does NOT provide sufficient vertical velocity to exceed the settling rate of the gold, you don't need a permit. You don't need anything because it won't pump gold up the hole! :confused:

The calculation:

Based on the Trash pump specified above, at 16000 GPH = 267 GPM = 0.60 Cubic Feet per second;

Given the illustration above that gives the cross-section of the suction drill?, The downward velocity works out to 6.54 feet per second and the upward velocity is 6 feet per second.

I just got back from the hardware store. I am preparing a few short videos on the settling rate of fine gold. :smile:

- Geowizard

  
LipCa
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Re: Fine Gold Sluice Design Help Needed ( 01:35:59 SatFeb 18 2017 )

"A STUDY OF FACTORS SUSPECTED OF INFLUENCING THE VELOCITY OF FINE GOLD PARTICLES" by the University of Alaska, Fairbanks.

Sorry I couldn't make the link from PDF file...

  
geowizard
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Re: Fine Gold Sluice Design Help Needed ( 02:53:46 SatFeb 18 2017 )

That is an excellent reference on Settling velocity!

http://pubs.dggsalaskagov.us/webpubs/mirl/report_no/text/mirl_n76.pdf

In my tests today, after taking a few hours to set up the test fixture, I ran the following items:

1. 4.5 mm Copper plated BB, .328 grams - spherical shape.
The settling velocity was 52.0065 cm per second.

2. #7 Lead shot - spherical shape
The settling velocity was 51.28 cm per second.

3. Black sand 20 mesh
The settling velocity was 21.92 cm per second.

4. Gold, 20 mesh, flatness approx. 10.
The settling velocity was 22.91 cm per second.

The fluid was clear well water.

Looking at the appendix to the paper LipCa referenced above, these numbers are in the relative size, mass, shape factors given.

What does it mean? :confused:

The water pump that was suggested in the beach sand drill results in an UPWARD velocity of 72 inches per second = 183 cm per second.

So, the upward velocity far exceeds the settling velocity!

Cool! :smile:

- Geowizard
[1 edits; Last edit by geowizard at 02:55:11 Sat Feb 18 2017]

  
dragline
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Re: Fine Gold Sluice Design Help Needed ( 05:13:57 SatFeb 18 2017 )

I believe that a general discussion in this thread pertaining to the physical characteristics of gold-bearing beach sand sediments is overdue. I am also inclined to believe that not all the members of this forum, or the readers of this thread, are sufficiently familiar with Oregon beach sand gold to understand what it is, where it came from and how one might go about recovering it.

Q1: Where does beach sand gold come from?
Answer: Many ocean beach sands located close to the mouths of rivers having gold-bearing alluvial sediments contain placer gold that was carried to the ocean by those rivers. Beach sand gold can also originate more directly from the erosion of coastal or inland sediments by the erosive forces of the ocean or glaciation. There are many different ways that gold can wind up in ocean beach sands but a key common factor among all beach sand gold deposits involves the gold's secondary concentration. Without the forces of secondary concentration gold would be so widely dispersed in ocean sediments and beach sands so as to be in such low concentrations as to be almost undetectable and certainly unrecoverable.

Q2: How does gold become concentrated on ocean beaches?
Answer: Beach sand gold becomes concentrated thru a variety of forms of secondary concentration. One form of secondary concentration involves dilute gold bearing river sediments piling up in the ocean at the mouth of a river. As prevailing coastal currents and tides flow over these sediments the lighter blond sands tend to move more easily and further away along the coast from the river mouth while the gold tends to stay closer (not travel as far) from where river flood waters originally deposited those sediments. Another form of secondary concentration (sometimes referred to as tertiary concentration) occurs with ocean wave kinetics.

Q3: How do ocean waves concentrate beach sand gold?
Answer: Let us consider how gold is concentrated in rivers and streams. Gold is very dense (heavy) and tends to seek the lowest resting position in rivers or streams, usually close to bedrock. Right?
-- Wrong! Understanding how wave action (kinetics) concentrates beach sand gold will require that you suspend your beliefs and forget all your assumptions about how gold comes to be concentrated in rivers and streams. Rather than thinking that gold always seeks a resting position closest to the center of the earth, think instead that gold always seeks a resting position of lowest potential energy. Consider that ocean waves crashing on the beach involve a lot of kinetic energy as the force of the wave impact is sufficient to move blond sands, mineral sands and gold into an extremely chaotic slurry. As the wave travels up the beach the kinetics dampen, the wave slows and at a location close to the top of the wave's travels the solids settle out from the wave. The wave's velocity reaches zero at the highest point of it's travels and retreats back to the surf. Because the settling velocity differs between the lights and the heavies the mineral sands and gold tend to be stranded high on the beach whereas the blond sands tend to retreat back with the wave into the surf.

Q4: What are the characteristics of beach sand placer gold deposits?
Answer: Beach sand gold deposits are generally associated with black sand (or mineral sand) deposits referred to as lenses. These deposits are called lenses because of their lenticular cross section when viewed from the walls of a trench dug up the beach perpendicular to the shore. Some black sand lenses contain gold in concentrations worth mining and some contain little or no gold. Just because you find a black sand deposit on a beach known for gold bearing sands doesn't necessarily mean there will be significant gold there.

Q5: How rich can beach sand gold deposits get?
Answer: In the spring of 1852 two men, the Randolph brothers, set ashore on Whiskey Run Beach near Bandon, Oregon. These men had intended to pack inland the next day to prospect for gold but upon rising the next morning they discovered beach sand gold surrounding their camp. The gold glittered brightly in the morning sun and upon testing those sands in their pans they determined to prospect the gold there on the beach instead of heading inland. The brothers built a long tom sluice and within a few weeks had amassed a fortune. In need of supplies the brother set off for the trading post in Roseburg, Oregon, and owing to the huge quantities of gold they had brought with them a few of the inhabitants of Roseburg decided to secretly follow the brothers back to their diggings. Needless to say there were soon many hundreds of miners descending upon Whiskey Run Beach sufficient to found the boom town of Randolph and many profitable beach miners. It was said that the first few dozen men to arrive on the beach were capable of earning $1,000 per man per day at a time when gold was selling for $10 per ounce. In 1887 the Bureau of Mines surveyed Oregon beach placer mines and methods and estimated that owing to the extremely fine gold mesh that the Randolph miners could at most only have been recovering between 40% and 50% of the gold passing thru their sluices. Given the estimate that one man could shovel no more than 4 cubic yards of heavy mineral sands per day into the long tom sluice one can deduce that the Whiskey Run Beach sands of 1852 and 1853 contained as much as 50 to 60 troy ounces of gold per cubic yard. Chaos and fistfights were numerous among the hundreds of miners that had come to the beach but finding the richest diggings already crowded with other men. The Oregon Territorial Sheriff caught wind of the Whiskey Run Beach commotions and upon arriving regulated each man to no more than a 10 foot by 10 foot claim that they had to mark and stake out with string. But as you might have guessed, all good things nust eventually come to an end, and to an end indeed did the rich diggings of Whiskey Run come when in January of 1855 a winter storm of gargantuan ferocity descended upon Whiskey Run Beach and stripped away the paying sands replacing them with the worthless blond sands we see so common on this beach today. One might ask the question...

Q6: Where did all of those rich beach sand gold deposits go after that huge winter storm of 1855 stripped the beaches bare?
Answer: Good question. In fact, it wasn't just Whiskey Run Beach gold deposits that were wiped out in the winter of 1855. Many other rich Oregon beaches were also wiped out including the extremely rich diggings of Gold Beach, Oregon. Might any forum members here have any ideas about where those rich beach sand gold placers went or might be found today? If you do, share your ideas and thoughts with the rest of us.

dragline

  
geowizard
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Re: Fine Gold Sluice Design Help Needed ( 14:41:49 SatFeb 18 2017 )

dragline,

It's "in a BANK in Beverly Hills - in somebody else's name." :confused:

The problem with exploration aka "prospecting" for GOLD is that the process involves conjecture!

It's anybody's guess?

What has to be done is called a "survey". In this case, a "Geophysical survey". Exploration companies, today, use the available technology in their search for precious metals deposits. The technology is in the form of Pulse Induction metal detectors - only on a larger scale.

Companies like Zonge International http://zonge.com/ have systems that they sell, lease, or offer as a service.

NanoTEM;

The NanoTEM system is a good example of a Pulse Induction system that can be used to perform a geophysical survey for mineral deposits.

Whites TM808;

I would also suggest - in the case of shallow gold deposits, the Detector that Whites Electronics sells. It is low cost and easy to use. It will detect large masses of metal or mineralized deposits within six to ten feet.

Using electromagnetic systems around a salt water environment is a challenge because salt water is conductive. Fresh water estuaries or inlets represent good targets where salt water is less of a problem.

There are other instruments that can be rented or purchased that are in common use for shallow measurement of conductivity.

- Geowizard
[2 edits; Last edit by geowizard at 15:21:05 Sat Feb 18 2017]

  
dragline
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Re: Fine Gold Sluice Design Help Needed ( 17:32:46 SatFeb 18 2017 )

Geowizard,

You bring up a good point about the Whites TM808 metal detector. I've thought a lot about the types of metal detectors that might be capable of detecting the presence of a large dense deposit of mineral sands on or off the beach and the Whites TM808 was one detector I thought might be up to the task.

I am having problems finding any references or feedback from users of the Whites TM808 that have successfully employed this detector specifically to locate black sand deposits either on the beach or off. The vast majority of references I'm finding from users of this detector concern their concern about NOT wanting to detect black sands, i.e. wanting to null or balance out the effects of black mineral sands or other mineralized deposits while searching for deeply buried iron or metal objects.

Whites specifications for this detector specifically state that:

"Its dual-race track antenna works with adjustable ground balance to reject ground minerals and detect deeper metals. With larger objects, it can even detect up to 20 feet deep."

Does this mean that by adjusting the ground balance on this thing that one might balance out closer smaller black sands while then detecting larger deeply buried black sand deposits? Might this thing also detect large black sand deposits under shallow ocean salt waters or buried under blond ocean beach sands? I kinda doubt it but I am not really finding anyone with anything to say about these things.

dragline

  
geowizard
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Re: Fine Gold Sluice Design Help Needed ( 19:54:38 SatFeb 18 2017 )

The problem with opinions about detectors;

Mine works. Mine doesn't work. You need to buy a Whites! You need to buy a Minelab! My Minelab works better. My detector works better if I turn up the discrimination. My detector works...

Oh... I have 20 years of experience and you only have 5 minutes - so I find more gold because...

The problem with detectors is people!

You don't need to know how a detector works to learn how to use one. This Forum and a few others have had discussions about different detectors and different detector technologies.

The real problem is understanding the difference between "cause and effect" and "cause and coincidence"!

I never found any gold until I picked up a whiz-bang 10 inch coil! Then, the very next day, I found a four pound nugget! :smile:

Everybody runs down and buys a whiz-bang 10 inch coil!

So and so finds a pocket full of nuggets every day and I haven't found anything in ten years!

The discussion goes on and on...

It is frustrating to anyone that spends money on a detector and "It doesn't find GOLD!"

Is a detector a solution or a problem?

Metal detectors are actually a SOLUTION if the detector is operated properly, meets a well defined specification and is used with an understanding of its limitations. Another important reality is you spend most of the time detecting nothing! That's the part that has the greatest psychological effect. Prospecting requires "patience". You cannot quit! You might feel like you want to quit because you didn't find anything and therefore come to the conclusion that you are wasting your time and energy for nothing! That's a serious problem. You are subject to ridicule by your friends and family for having wasted your time prospecting!

What is the solution?

The solution is to take the time to study the various types of metal detectors and learn about how they work. A metal detector is complex today because it may have features that are not completely understood.

Ground Balance:

One of the features found in modern metal detectors is "Ground Balance". The option of ground balance may be manual or automatic. Either way, the process of ground balance serves to correct for mineralization in the ground. The solution can become a problem! In the case of manual adjustment, an increase in rejection of ground mineralization can affect sensitivity. There is a different threshold with every adjustment. The other option is automatic ground balance. The solution can again become a problem. The metal detector uses a microprocessor or microcontroller to make a decision on the ground balance applied to the detector. The user can only assume the automatic feature is being properly implemented in the processor. Small gold can become impossible to detect if the ground balance is set higher than necessary.

Discrimination;

Many detectors can discriminate between ferrous and non-ferrous metals. I have detectors that can be adjusted to select certain responses and reject other responses depending on their phase angles. Unfortunately, there are many cases where gold may have iron attached. There are many cases where gold may be associated with black sand. Again, there are detectors that have adjustable, digitally selectable, and automatic discrimination.

Improper setting of discrimination can be a problem.

Sensitivity;

The sensitivity threshold becomes a big source of problems for many detector operators. The sensitivity is just that - sensitivity. The amount of response varies according to the size, orientation and conductivity of each target. Depth plays a major role in detecting targets. Sensitivity should be set to a point that you can hear a slight response continually. Here's where it gets touchy. There are those that want silence. The theory is that you can hear faint signals.

Calibration;

In my opinion the most important thing to do with a metal detector is have a few calibration cards with different targets glued or taped on to each card. Cards with different size nuggets, types of trash, etc. The cards can be placed in different soil types and the detector tested with the cards at various depths and in combination with other cards.

- Geowizard

  
geowizard
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Re: Fine Gold Sluice Design Help Needed ( 20:16:55 SatFeb 18 2017 )

Detecting beach gold;

Small, fine gold does not create a detectable response!

There may be 10 ounces of fine disseminated gold and it is not detectable.

Black sand IS often found in abundance. Certain conditions are possible where abundant black sand has sufficient conductivity that it is detectable... AND there may be associated fine gold that would otherwise not be detectable. It is well known and understood that gold is commonly found in deposits that are polymetallic. Those polymetallic deposits often include iron in different forms and the placer deposits reflect the mixture of all of the heavy metals.

Knowing that, a prospector can use metal detectors that are designed for deeper investigation and realizing the association of iron with gold, increase their probability of success! :smile:

- Geowizard

  
redwood
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Re: Fine Gold Sluice Design Help Needed ( 23:26:34 SatFeb 18 2017 )

A very good thread you guys. I truly have learned a lot by reading of the proposed processes, methods envisioned, problems which might arise and solutions for success.

What a diverse group of people we prospector / miners we are.

Dragline, do mind if I re-post your above questions and answers about the nature of beach gold to another forum keenly interested in this subject?

Thanks,
Mike
[3 edits; Last edit by redwood at 23:35:05 Sat Feb 18 2017]



---
Joe's Cabin Rental
 
 
dragline
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Re: Fine Gold Sluice Design Help Needed ( 01:02:36 SunFeb 19 2017 )

Redwood,

Sure, repost if you like, but give a link back to the discussions here on Alaska Gold Forum if it is practical for you to do so.

Do you have any theories about where all the rich Oregon gold beach sands went after that 1855 winter storm? It is a bit of a mystery how so many extremely rich gold sand beaches up and down the Oregon coast were all negatively impacted by this one storm. One might think that where one beach lost gold another beach might have gained, and this may have been the case but there were no reports of such extremely rich gold baring beach sands after this storm.

What are your thoughts about where all these rich gold beach sands may have gone or may be found today?

dragline

  
dragline
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Re: Fine Gold Sluice Design Help Needed ( 01:56:45 SunFeb 19 2017 )

I determined that my 7 HP trash pump should be capable of pumping a 50% solids silica sand slurry from a depth of 20 feet thru a 4 inch inside diameter PVC pipe in seawater to my sluice located at the surface. I based these estimates upon an overall system efficiency of 14%, although I believe an overall efficiency as high as 18% might be achieved with optimal mechanical design and at higher material and fabrication costs.

Given:
1. Seawater specific gravity = 1.03 g/cc
2. Silica specific gravity = 2.6 g/cc
3. 50% solids silica sand slurry = (2.6 g/cc - 1.03 g/cc)*0.5 = 0.785 g/cc
4. 1 gallon 50% solids silica sand slurry weighs 6.55 pounds in seawater
5. We want to lift a 50% solids silica slurry from 20 foot depth in seawater.
6. 20 feet of 4 inch ID Sch 40 PVC pipe has inside volume of 13 gallons.
7. In seawater, weight of 13 gal 50% solids silica sand slurry is 85 pounds.
8. Minimum vertical slurry velocity to prevent separation of heavies is 5 ft/s.
9. Worst case 14% efficiency for 7 HP (3,850 ft-lbs/s) nets 539 ft-lbs/s.
10. Estimated lifting velocity for 85 Lbs slurry is 6.34 ft/s.

Therefore: At a dredging depth of 20 feet and an overall system power efficiency of 14% a 7 HP gasoline engine trash pump should marginally be capable of lifting and delivering a 50% solids silica sand slurry up thru a 4 inch inside diameter PVC pipe to a sluice at the water's surface. However, the calculated power delivered by this system is only 27% higher than the power demanded for such an undertaking.

Then again: If I were to be successful in placing the dredge nozzle into a large gold baring black sand deposit the specific gravity of the black sands would be significantly greater than the blond sands that served as the basis for the above estimates. I calculate that this 7 HP system would be capable of lifting black sands to the surface from a maximum depth of about 10 feet before the vertical slurry velocity fell below the minimum 5 feet per second required to prevent separation of coarse gold from the lighter silica and black sands.

One last comment: Given that the vast majority of the beach sand gold that I am familiar with on the Oregon coast is finer than 40 mesh and averaging 80 to 100 mesh, I do not believe that hitting a black sand deposit at 20 feet will be a huge problem if the vertical slurry velocity were to slow to as low a 2 to 3 feet per second. Oregon beach gold typically has flattened shape characteristics that slow settling velocity relative to an equivalent spherical gold particle at the same mesh size. When mining Oregon beach sand gold we are typically not worried too much about gold sizes 325 mesh minus and gold particle sizes 40 mesh plus are almost non-existent as well. Take a look at the charts below and double check my calculations if you like.



dragline

  
dragline
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Re: Fine Gold Sluice Design Help Needed ( 01:08:47 MonFeb 20 2017 )

Here is a layout for the coupling configuration of the PVC pipe drill segments. I've decided to go with the off-center concept such that the 2 inch diameter hydraulic supply will be spaced slightly away from the 4 inch diameter suction pipe so as to accommodate slip fit coupling fittings between PVC pipe segment assemblies. I'll probably employ an 1/8" o-ring so as to seal the pipes to couplings once inserted. We're not having to deal with much pressure here so the o-rings are not intended to prevent any and all leakage but to be just tight enough to maintain pressure and suction.



The coupling assembly will be cemented and/or welded together along with 5 foot sections of both 4" and 2" Sch 40 PVC Pipe. This will create an assembly consisting of both the 4" and 2" PVC pipes that when slipped together and latched securely will form the entire vertical well drilling assembly.

I haven't designed the hydraulic cutting head yet but I'm debating whether to incorporate a lifting jet at the cutting head or to position the lifting jet at the head of the sluice. It probably will be more efficient to position that at the head of the sluice since it will reduce the flow necessary going down the 2" pressure pipe. Positioning the lifting jet at the sluice will also make it a lot easier to control independently of the flow to the hydraulic cutting head.

A lot of you will disagree with me about my off-center well drilling pipe segment assemblies, perhaps thinking this configuration is not a good idea. If you have no experience working with unconsolidated (loose) sand sediments, like I have, you might not realize that this hydraulic cutting head will not have any difficulty establishing an actively fluidized slurry surrounding these pipe segment assemblies.

Some of you are probably thinking that if I manage to get this pipe assembly 10 or even 20 feet deep in the sands (as is my goal, realistic or not), that the sands might collapse inward and cause this segment assemblies to become stuck. Perhaps requiring a winch to extract it out of the sand sediments. But this will not happen for a variety of reasons.

At any rate, a mechanical winch in the boat would be completely unnecessary since I actually have a hydraulic cylinder right at hand. All that I would need to do is to close the 4 inch ball valve at the head of the sluice which will cause both the 2 inch hydraulic supply pipe and the 4 inch suction pipe to become positively pressurized. With both pipes pushing 16,000 gallons per hour downward at up to 42 PSI the the net lifting pressure on the drilling section pipe assemblies would be 665 pounds which should lift those pipes out of whatever situation they got into. But again, such a condition as a stuck drill head or well pipe assembly is highly unlikely, in my opinion.

dragline

  
geowizard
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Re: Fine Gold Sluice Design Help Needed ( 17:39:56 MonFeb 20 2017 )

dragline,

With reference to experience in a sand box;

I get this all of the time. There really isn't much more that a person with one day on the beach doesn't understand about beach sand than somebody understands with a lifetime of experience. The relevant amount of experience doesn't change or support a flawed theory.

Good science dictates you will make a water filled crater. The wet sand will continually fill the hole as fast as you can pump it out. I personally am wondering what the objective might be at that point. :confused:

Mining requires a plan. The plan might be to mine a large area that contains gold. Without having determined IF there is gold, the drill becomes an exploratory tool.

- Geowizard

  
geowizard
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Re: Fine Gold Sluice Design Help Needed ( 18:58:34 MonFeb 20 2017 )

dragline,

If the objective is to suction a hole in wet, saturated sand, then there's the reality of; "What happens when you make a hole in wet sand?"

We had a discussion last year on this topic. The scenario was up on the beach in dry sand and what happens to a drill when drilling into WET, saturated sand.

The point was made that saturated sand goes with the flow. When a hole is made in sand below the water line, the sand will flow into the hole.

Gravity defines a "slope of natural repose". Saturated slurry will move under the force of gravity to the lowest possible point. That's usually the deepest point in the hole.

- Geowizard
[1 edits; Last edit by geowizard at 19:02:08 Mon Feb 20 2017]

  
dragline
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Re: Fine Gold Sluice Design Help Needed ( 21:43:42 MonFeb 20 2017 )

Geowizard,

Exactly. You do seem to understand the physical characteristics of beach sand sediments in response to suction dredging fairly well. The net results of dredging down 20 feet is that the loose sand sediments above the dredge nozzle and up to the surface sands quickly liquefy and fall down the hole to the suction nozzle. As the dredging continues the diameter of the liquefied slurry pit at the surface grows ever larger. Once liquefied the forces of gravity upon the liquefied sand slurry will create an almost level pool of mud. As the dredge continues to suction slurry the pit grows ever larger as the semi-consolidated sides of the pit slump down and become liquefied and mixed into the rest of the mud pit.

Not everyone understands loose sand sediments as well as you do so I commend you for your astute comments. Of course I also understand beach sands so we are in complete agreement about what can be expected if I were to drill a hole 20 feet deep and continue suctioning sand slurry from that depth. While you and I understand these things reasonably well, not all the forum member or readers of this thread are as familiar with unconsolidated beach sediments as we are. So for the edification of our other forum members it is a good thing that we are having this conversation.

Your comment about using this proposed dredging method as an exploratory tool is also on target. What would happen if I put my dredge nozzle down twenty feet, and then take a half hour to process 2 cubic yards of beach sand sediments just to find out that the sediments I've been dredging for the last half hour were too low value to be profitable? Answer: I'd move on. Gee... a half hour wasted? Nope, not wasted. A half hour spent determining that the specific location was not profitable, and that is a good thing because the next half hour can be spent dredging another spot and seeing whether the pay grade was profitable or not.

If you were ever a profitable gold miner you have in all likelihood used exploratory sampling methods to determine the location of the most profitable ores. I couldn't imagine engaging this effort without exploratory sampling. Bear in mind that should this dredge I'm designing and building actually be capable of reaching a depth of 20 feet the sampling methods and interpretation of those results might be somewhat complex. But in regards to sampling from a depth of 20 feet the chances of finding a rich ore body are significantly enhanced relative to sampling from much shallower depths.

dragline

  
peluk
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Re: Fine Gold Sluice Design Help Needed ( 05:24:43 TueFeb 21 2017 )

Dragline,your idea will not work. the "Subby" is an unworkable design and the suction tube is going to just get stuck and stay there. The lenses you spoke of are discontinuous and some are heavier in gold than others which may be even more unprofitable.

From the beginning of your thread you were looking for slurry velocities and wondering why they weren't being submitted...unless I'm mistaken. Then you published your design. I hoped in reading about it it would not have different levels terminating in squared turns.I wondered why lifting the sluice to different grades until optimal settling and selection was achieved was of no interest.

Your closed design does not incorporate gravity as a method of separation but merely as an afterthought or it some more apt engineering term.

I spent enough time going over this so I'll try to point out some failings that might help you abandon this project.

The Elutrian tube does have a friction factor to contend with.Light gold will seemingly lose interest in moving along as it drags along the tube sides. And,your plexigas demo must be thoroughly lined with plexi whether clear or backed to have the same friction drag on both sides of the chute.
In your "Subby" with the predominance of light flat gold present in the material,collection of that gold will be hit and miss.
I'll continue with a new entry before I lose this one so I'll post now.

  
peluk
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Re: Fine Gold Sluice Design Help Needed ( 05:49:32 TueFeb 21 2017 )

Problems dredgers run into with some of the triple sluices will show themselves in your design as well,closed or not.Slow speed of flow and dense heavy sands eventually pack up.

Because your sluices are closed and pressurized,the same failures that submarine dredges contend with will also be present. Hydrodynamics under water are different than in open sluices on the surface. Once gold is in suspension under water there is little reason to come out of that state because of the increased buoyancy. Gold will coast right out with the tails underwater, if it is light.That which is collected is by guess and by gosh right along with other heavy sand and it will be distributed throughout that sand not really successfully selected by any riffle action.

On your surface mounted "Subby",the slurry will go through and the matts will immediately plug the gold which has not been weighted down by red and black sands,because that is the only reason for it to collect,will scoot along with the flow. The water as always will take the path of least resistance right over the top of the sand bed on the now buried mats.

Ultimately,the sand will pack up the area of the JKL bend and the show will be over almost immediately after starting.

The only reason any mat will select is because it is tilted.Your device cannot be tilted and if it could,the heavy minerals would still be in a closed sluice with more buoyancy.I'm not entirely sure that the buoyancy would be the same as if the device were underwater but I have seen some expensive dreams on this beach in Nome excel at one thing universally.They cost lots of money and make none.
There's a Russian that wants to do something with a suction pipe on my beach claim next Summer briefly before the dredging season starts. It is just an idea he has.It is connected to his dredge.It shouldn't be as expensive and I don't expect he'll be there long.

Wow,I just can't believe how much people will throw away up here on bad ideas.

I

  
geowizard
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Re: Fine Gold Sluice Design Help Needed ( 15:15:15 WedFeb 22 2017 )

So, it goes. :confused:

We have one more professional opinion.

The problem, as I see it is that the few members that are willing to take their time to contribute an opinion are either ignored or patronized.

This isn't a debate.

There is no debate on the behavior of saturated sand. There is no debate on how a sluice works.

There is no debate on the laws of physics or the method of calculating the acceleration of a falling body! Newton figured that out centuries ago. Most of the laws of physics represent what we know about the world around us.

Like Peluk, I can offer many stories about ideas that never got off the ground. It's nothing personal. It's the reality of going through the process of invention.

Considering the international effort to devise new and novel approaches to gold recovery, the probability of coming up with a new, novel approach is extremely low. There are currently hundreds of "projects" and possibly thousands of "projects" in various levels of development in garages, workshops, and on the beaches world-wide. It's nothing new. The question for any creative do-it-yourself designer is; "Why won't it work?" The process of proving a concept or "hypothesis" is to approach the proof from the side of proving it WON'T work! That's the hard part. The person that has the brainstorm has the "burden of proof". :smile:

- Geowizard

  
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Re: Fine Gold Sluice Design Help Needed ( 15:51:45 WedFeb 22 2017 )

Design Help Needed;

Consider the "Dreamliner";

Boeing designed the Dreamliner using CAD technology. Nobody had previously built a Dreamliner! :confused:

The process of designing a Dreamliner involved the process of computer simulation. Designers didn't draw the airfoils and the fuselage. The designers specified the inputs to a CAD package and the CAD system did the rest of the work.

The WORK;

The work is the process of applying what is known to design something that is unknown! Certain principles that involve aerodynamic LIFT and DRAG and structures and materials and weights and balances and the FORCES of velocity and acceleration are rolled into computer modeling and computer simulation.

How thick is the Plexiglas on the windows? :confused:

How much LIFT is required?

How much DRAG is imposed?

Will it get off the ground?

Is it "Rocket Science"?

Marketing dictates most of what goes on in the world of new designs, manufacturing and engineering.

What's the market?

Is this a "one off" design?

If dragline owns it, has a Patent on it, wants to control the production and distribution, what might be the market?

Everyone can chime in with their vote. It doesn't matter who wins. If it doesn't work or if there's only a one-off production, there's not much point in considering a patent. The market is limited to a specific application.

Discussion on get rich ideas provides a certain amount of amusement. Nobody has any "skin in the game". :smile:

- Geowizard
[2 edits; Last edit by geowizard at 15:54:11 Wed Feb 22 2017]

  
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Re: Fine Gold Sluice Design Help Needed ( 16:43:06 WedFeb 22 2017 )

Archimedes' Principle (212 BC);

"Any object is buoyed up by a force equal to the fluid displaced by that object."

So, a gold nugget having a displacement of one cubic centimeter, displaces one cubic centimeter of water.

Gold having a mass of 19.38 grams per cubic centimeter is buoyed up by a force of one gram per cubic centimeter when submerged in water. It doesn't matter if the gold is in a tank above water or the gold is in a tank below water. The gold is buoyed up and is lifted by the amount of water it displaces. :smile:

- Geowizard

  
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Re: Fine Gold Sluice Design Help Needed ( 18:27:37 WedFeb 22 2017 )

Two years ago,a guy from Texas came up to Nome with an idea for beach dredging. He had a trommel connected to a dredge hose. He saturated an area of sand immediately in front of his nozzle and started up. The sand would not make the climb up to the hopper which was 6' above the beach surface.So he added more pressure to the jetting.It was not a suction head. They were inline jets set back from the nozzle head.As I think back it probably involved another pump in line as well. He went to a smaller dredge hose also.Before adding the extra pressure,the sand just sat in the hose and never really started up the incline to the hopper. After the improvement,some went up and the rest plugged the hose stopping progress. It was all just frustrating him but he kept at it until he finally went broke having used up all his buffer zone. he sold his whole rig,and the truck was the last to go.

The beach where he blew out his waste was rich because he had never really developed his sluice bedding to catch fine gold.

It seems that sand moves through a dredge hose more easily when it is submerged but your reference to Archimedes principle would say no,that's not the case.So,it must just be the higher HP applied from a larger pump and jets placed in line at a more optimal position that make the difference.

It seems that in a closed sluice as with a submerged dredge and with dragline's idea,there is some lift from the friction as the water stream slides along the top of the sluice or even a dredge hose. I think that plays havoc with settling at least in terms of fine gold. I even wonder if the damper/flapper at the top of a beach box sluice creates a lift as the water passes out under it and then lifts fine gold into suspension before it has a chance to settle out. That would be at the bottom edge of the flap where a negative pressure would develop. At this point,I have used visqueen,poly tarp material and even cocoa mat for that purpose.
It is relevant because although the gold is suspended by the water it displaces,other forces come into play as well.

  
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Re: Fine Gold Sluice Design Help Needed ( 02:37:17 ThuFeb 23 2017 )

Peluk,

I respect you and your vast experience working with beach sand gold placers. I would therefore appreciate your taking the time to explain your comments when I have trouble understanding your thinking or logic. I'll respond as best as I can to your comments individually so that I can hopefully figure out whether your comments have merit.

Your comment: "Dragline, your idea will not work. the "Subby" is an unworkable design."
Response: Perhaps it is unworkable, but I am not intending to explore that specific design at this time. The "Subby" that I am intending to design for this current project is vastly different than the illustrations previously posted. I have not as yet posted illustrations for my current design, but I will hopefully get around to doing that soon.

Your comment: "...the suction tube is going to just get stuck and stay there."
Response: I believe that your concerns about the dredge nozzle getting stuck are unfounded. Of course I haven't generated or posted illustrations of my dredging nozzle yet but I have provided a cross section of the off-centered layout for the dredge pipe and hydraulic supply. I can only assume that you are tempted to pass judgments based upon limited information. Perhaps your opinions on this matter will change as I post additional illustrations... hard to say. Perhaps if you might explain why you thing it is going to get stuck I might better understand what your thinking and how to better respond to you.

Your comment: "The lenses you spoke of are discontinuous and some are heavier in gold than others which may be even more unprofitable."
Response 1: Yes, lenses are by definition discrete entities and therefore discontinuous. All ore bodies are discontinuous.
My response 2: Yes, ore bodies will vary in richness. Some are rich enough to be profitable, and some not. Again, do such a thing as uniformly rich ore bodies exist and do you have a point in making these statements?

Your comment: "From the beginning of your thread you were looking for slurry velocities and wondering why they weren't being submitted...unless I'm mistaken."
Response: True, I received no specific or quantitative responses from the forum members here in regards to slurry velocities.

Your comment: "I hoped in reading about it it would not have different levels terminating in squared turns."
Response: With my current design I'll have three 4 foot levels totaling 12 feet with two 180 turns between two of the three 4 foot levels. Do 180 turns concern you? If so, please tell me why. Have you seen problems with such a system that included these 180 turns?

Your comment: "I wondered why lifting the sluice to different grades until optimal settling and selection was achieved was of no interest."
Response: I find your comment difficult to understand but I'll assume that by "grades" you mean "slopes"? What your point might be about different "slopes" having an effect upon "optimal settling" I'm not sure. My subsurface sluice concept here operates at zero slope whereby the slurry velocity is tightly controlled by the slurry volume per minute introduced into the sluice. I hope you can understand how this works. If not, let me know and I'll do my best to help you understand.

Your comment: "I spent enough time going over this so I'll try to point out some failings that might help you abandon this project."
Response: Great! I wouldn't want to waste my time on a project that was doomed to failure. I eagerly await reading your comments that might help me understand the validity of your concerns.

Your comment: "The Elutrian tube does have a friction factor to contend with. Light gold will seemingly lose interest in moving along as it drags along the tube sides. "
Response: Let me just say that I am not concerned about the vertical dredging tube friction factor you speak of because I believe the high slurry velocity will nullify those effects and concerns.

Your comment: "And,your plexigas demo must be thoroughly lined with plexi whether clear or backed to have the same friction drag on both sides of the chute.
Response: Okay, but I don't see this drag effect as a problem. If the slurry velocity slows at the sides of the sluice, what's the big deal? All sluices have sides that slow the slurry.

Your comment: "In your "Subby" with the predominance of light flat gold present in the material, collection of that gold will be hit and miss."
Response: Duh! Extremely fine, i.e. 100 to 325 mesh flat gold can be very difficult to capture with any gravitational recovery system. Have you previously operated a subsurface sluice? Do you have reasons to believe that a subsurface sluice might be inferior to a surface sluice? Let me know your thinking, please. I built and operated a subsurface sluice for an 8 inch dredge back in the late 1970's. Admittedly, my Subby design wasn't that good back then. It captured virtually 100% of the coarse gold but it lost a lot of fines that were captured in the surface sluice below. My current Subby project will hopefully not suffer those same problems, at least that's my intention.

dragline
[2 edits; Last edit by dragline at 04:20:35 Thu Feb 23 2017]

  
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Re: Fine Gold Sluice Design Help Needed ( 04:02:14 ThuFeb 23 2017 )

Peluk,

Your comment: "Problems dredgers run into with some of the triple sluices will show themselves in your design as well,closed or not.Slow speed of flow and dense heavy sands eventually pack up."
Response: "I can tell you that this will not be a concern because the Subby sluice cannot pack up because it is a Subby sluice, i.e. there is no air and no slope and it doesn't function like any sluice you're familiar with. The slurry velocity is constant throughout the entire length of the sluice. Sure, it'll slow down slightly at the sides but that won't be a problem. All roads lead to China (tails), as they say.

Your comment: "Because your sluices are closed and pressurized,the same failures that submarine dredges contend with will also be present."
Response: Please enumerate and describe those potential failures for me.

Your comment: "Hydrodynamics under water are different than in open sluices on the surface."
Response: Really? Your last statement needs explaining. All hydrodynamics are by definition "under water." If moving water is contacting air you may have waves, turbulence and bubbles, all not good things. A Subby sluice is vastly superior to a sluice contacting air. If you don't believe me please convince me otherwise.

Your comment: "Once gold is in suspension under water there is little reason to come out of that state because of the increased buoyancy."
Response: Huh? Gold isn't buoyant (unless it clings to air), it doesn't think, it doesn't move about under it's own powers, and it has no independent ability to levitate or defy gravity. When in water gold settles, period. If the water is turbulent it may not find secure sequestration or it's settling time may be prolonged. Fine gold sluices are most efficient when they minimize turbulence and that is what a Subby sluice does better than any surface sluice.

Your comment: "Gold will coast right out with the tails underwater, if it is light. That which is collected is by guess and by gosh right along with other heavy sand and it will be distributed throughout that sand not really successfully selected by any riffle action."
Response: Nope. Gold isn't going to coast out of my Subby sluice. It is going to be captured and retained for very specific reasons, i.e. the Subby sluice has riffles that create eddies in the slurry flow that cause the fine gold to find sequestration. You can say all you want about my Subby sluice not capturing fine gold but if you can't give me any logical reasons to support your statements then I apologize that I have no reason to believe you. Please help me understand your thinking.

Your comment: "On your surface mounted "Subby",the slurry will go through and the matts will immediately plug the gold which has not been weighted down by red and black sands,because that is the only reason for it to collect,will scoot along with the flow. The water as always will take the path of least resistance right over the top of the sand bed on the now buried mats."
Response: Goodness. Riffles work to capture gold from the eddies they create. You seem to be saying that riffles in a subsurface sluice don't create eddies because they do not behave like riffles in a surface sluice. Is this what you're saying? From my perspective it seems you believe there is something magic that happens to a flow of slurry when air is in contact with its top surface as compared to some other material that isn't air. From my perspective your comments seem completely devoid of logic and lack any basis in physics. If that is what you mean to argue all I can say is... I respectfully disagree and I encourage you to give a logical argument as to why what you are saying is valid.

Your comment: "Ultimately,the sand will pack up the area of the JKL bend and the show will be over almost immediately after starting."
Response: Nope. Nothing like what your suggesting will happen. The Subby sluice has a clear long aperture that leads to tails. There are no restrictions. Think of it as a rectangular pipe. Your logic seems to dictate that water and slurry will flow just fine thru a round pipe but no, a slurry cant flow thru a rectangular pipe because it is going to plug up. Is this your argument?

Your comment: The only reason any mat will select is because it is tilted.Your device cannot be tilted and if it could,the heavy minerals would still be in a closed sluice with more buoyancy. I'm not entirely sure that the buoyancy would be the same as if the device were underwater but I have seen some expensive dreams on this beach in Nome excel at one thing universally.They cost lots of money and make none.
Response: Fortunately for me, I'm not on your beach. I'm here in Oregon where the laws of physics apply. If you can't see how a set of riffles in a sluice can't work without a slope to those riffles, fine. There probably isn't anything I can say to convince you otherwise. However, I can tell you that my Subby sluice would work with increased efficiency if the slope were heading up hill. I'm not trying to blow your mind. I'm just stating a fact.

Your comment: "There's a Russian that wants to do something with a suction pipe on my beach claim next Summer briefly before the dredging season starts. It is just an idea he has.It is connected to his dredge.It shouldn't be as expensive and I don't expect he'll be there long. Wow,I just can't believe how much people will throw away up here on bad ideas."
Response: I hear you. I read that book (forget the name) about all the failed ideas up there in Nome at the turn of the last century. They were shipping up huge dredges and other mining equipment that worked great on river placer claims just to find out that the gold washed right thru their sluices and didn't even slow down. Hah! There are a lot of clueless people out there and gold miners are no exception.

dragline

  
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Re: Fine Gold Sluice Design Help Needed ( 04:48:15 ThuFeb 23 2017 )

dragline,

In your post above, you said;

"Your comment: "Dragline, your idea will not work. the "Subby" is an unworkable design."
Response: Perhaps it is unworkable, but I am not intending to explore that specific design at this time. The "Subby" that I am intending to design for this current project is vastly different than the illustrations previously posted. I have not as yet posted illustrations for my current design, but I will hopefully get around to doing that soon."

So the subby design went through three or four modifications and all of the discussion to date...

and...

That's NOT the "current design". :confused:

I am starting to think you are playing some sort of game here on the forum. You have solicited help with a design that you feel you have superior knowledge and understanding of and the design continues to morph into new renderings and then that's NOT the current design.

I get it. It's a GAME.

- Geowizard

  
Fleng
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Re: Fine Gold Sluice Design Help Needed ( 17:43:57 ThuFeb 23 2017 )

I don't think it is a game. I think that dragline values the conversation as many of us do. Experience is valued and apprecieated. The thing is that nobody wants to reinvent the wheel especially if a substancial investment is made.

That said, I would like to hear what dragline learns from his operational tests and his subsequent fine tuning.

Some of my favorite quotes:

The space elevator will be built about ten years after everyone stops laughing.

"All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident." - Arthur Schopenhauer

  
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Re: Fine Gold Sluice Design Help Needed ( 21:09:40 ThuFeb 23 2017 )

Fleng,

You don't have to wait.

Take a box and fill it up with water and dirt.

Pump more water and dirt into it!

Then fine tune it. :smile:

- Geowizard

  
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Re: Fine Gold Sluice Design Help Needed ( 03:40:33 FriFeb 24 2017 )

Placer Gold mining is a mature science;

With centuries of development and understanding of the relatively simple process of extracting gold using gravity, there really isn't much more science to be added to our present understanding.

The door is certainly open for new discoveries and new processes. :smile:

The price of gold and the cost of prospecting weigh heavily in the growth of the industry.

New techniques are under pressure to increase performance of recovery while offering lower cost.

Gold prices seem to be on the rise recently. Personally, I am optimistic that with many of the shifts in economic policies being put in place, gold may be in a good position for a bright future.

What is needed?

What is needed is more new gold deposits and access to those deposits. Without gold, we don't need new whiz-bang recovery systems. Not even much need for discussion either. With increasing gold prices, combined with rolling back regulations and opening the Federal Domain to gold prospecting and mining, we can all have reason for optimism.

- Geowizard
[1 edits; Last edit by geowizard at 03:42:22 Fri Feb 24 2017]

  
peluk
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Re: Fine Gold Sluice Design Help Needed ( 06:16:52 FriFeb 24 2017 )

Dragline,I'll break this into a couple of posts so I won't lose it. It will be in the form of short comments point by point or it will cover most of your questions anyway.I think you have your mind made up so all you have to do is what the folks in Missouri insist on ...."Show me"....when it's on line.

1)"Subby" as shown is not the final design.OK,I think there was some mention of theft of secrets if published. That makes sense but the principles are about the same.
2)You are content to probe down to a depth that may contain a lens which may have gold in it of minable quantities. All the while you are dealing with fluctuating tides,no real retrieval system for you stuck piping,and no real experience lifting sand from depth. I think that part is a sketchy undertaking.
On the surface,mining would definitely be less risky.You could drill sample,have magnetometric charts and resistivity charts or bucket or blade to expose pay.
I've seen sand grab an 8" suction hose which just dove to China before they could shut off the pump.It was a similar operation in ways and a truck was needed to pull out the hose with a winch.No need to point out the differences. You'll see the similarities are what you will learn to respect.
3) Slurry velocity feedback is not there but you will proceed. Ok,I'll tell you the slurry velocity you need. Make it just as fast as you can because it is not something you can afford to alter. Your sluice is operating without an incline and that will spell disaster for anything less than full tilt.It will plug up.It will plug up from that alone but you have other features that will assist in plugging it up.

"A body in motion stays in motion until acted upon by a stationary force". That should be close enough to use as a reference for your 180 bends. When that sand flies to the outside of the bend and carries around,it will leave that on the inside of the bend to collect. Or maybe it will drag along in the sower flow to the inside of the bend at the outlet of the 180. It will travel at different speeds as the water taking
the point of least resistance abandons it.That coming up on the 180 will start feeling the effects of reduced pressure in the flow and it too will start to drop out with no grade to help flush it.

4)"Slurry velocity is tightly controlled by slurry volume." What I just mentioned I think might throw that idea out of whack.
5) Reference to the Elutrian tube was just of some importance to me because you will be dealing with friction and light flake gold which my make it cling to the tube or slow down. It may or may not be important. What might be more important is the tendency of the friction to extract oxygen from the water which might float the gold to the surface. The bends in the 180's may also create bubbles from extraction of oxygen.In plumbing,the oxygenated water erodes the piping over time especially at bends.

I'll close this one here before I lose it. (cont.)









  

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