The Evolution of Fluidized Sluices

[SRP_KBell]

This thread was created to educate forum members on the past, present and future of fluidized sluices. It is not intended to create anger or frustration but rather present information and foster discussion. The goal is to help members who may be interested in purchasing and using this technology.

In the early nineties, Howard Schmidt patented and sold the Schmidt Gold Trap Dredge (nicknamed the Bazooka) which used a unique dual venturi design to draw water into a trap through tubes with holes directed into the trap. The main objective was to fluidize the trap to create a material exchange to exhaust waste material and keep the heavy material while handling the high levels of throughput volume that a dredge nozzle creates. This system was marginally effective and very angle dependant.

Schmidt later attempted to create a similar process using only stream flow in a sluice called the Black Magic by adapting a shortened and modified trap design. This sluice retained the high levels of throughput but failed in achieving the fluidization, exchange and exhaust process of even the original dredge design. The main culprit for failure was not having any water pressure to drive the spray tubes that caused fluidization in the trap. Water pressure at the atmospheric line, (where water touches air) is zero. Having a box three or four inches under water also does not affect pressure to any degree. Also once the trap has material covering the holes of the spray tubes, the weight of this material creates additional resistance. At best, there will only be a very small amount of water entering the trap tubes, primarily due to following the path of least resistance.

One additional point needs to be clarified – Neither of Schmidt’s models created efficient (high percentage) gold recovery in a fluidized system. Throughput with no material classification was always the primary objective.

In 2003, work began to update the “fluid bed” concept in a stream sluice format. A full-length conical shape was adopted instead of the straight design of the Schmidt, and the trap was moved to the rear of the sluice instead of the center in the original configuration. The basic Black Magic tube system for fluidization was retained, and the water scoop lengthened. This combination of sluice shape and length of scoop made the tube fluidizing system susceptible to clogging and more difficult to clear once clogged.

This sluice retains the high throughput capabilities of the original designs but creates additional problems. Its conical shape increases water velocity in the trap which in turn increases material throughput speed and shortens the time for heavy materials to separate and fall into the trap. Another drawback in the design is that the trap operates at full material capacity like the original - Once full, the primary force is directed straight through the sluice and material entering the trap has no space to be processed. Also since there is no action on the incoming material to help facilitate separation and extraction, it exits the sluice without being fully processed. This newer design also retains the same tube fluidization method with the same issues of the original designs. These issues will plague any current or future products that use this design.

Fluid Dynamic sluices are the latest evolution in fluid sluices. They combine high rates of throughput but add opposing water forces entering on each side of the trap to slow the primary water flow and process the incoming material, facilitating separation and extraction and creating space for incoming material. There is also a mid trap partition that enhances extraction by further slowing material. Oscillation is also created as water passes through the sluice providing the necessary motion to facilitate the complete exchange of material in the trap. Another key feature is the flip-up material tray cover that allows you to visually inspect the trap or easily clean the sluice into a pan. Fluid Dynamic sluices also incorporate a “pass-through” water system that eliminates clogging issues that plague fluid bed systems.

The material throughput of the new sluice approach is about 85% of the current fluid bed design when comparing their relative sizes. However, there is a significant increase in the percentage of pay gold recovery which negates any material volume decrease. One last bonus of the Fluid Dynamic Sluice Design is that it is considerably lighter in weight and more compact in size making it much easier to carry. This allows prospectors and miners to travel more quickly and safely to their mining locations or provide the ability to test distant locations. With these advancements, true progress is moving forward.

 

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[Goodyguy]

I understand what you are saying about the shortcomings associated with the Schmidt Black Magic and the later redesign of his concept.

I do agree that there is a sleight gold loss due mostly to extra high flow conditions as well as the difficulty for certain shapes to be captured due to them remaining in the laminar flow. I also understand what you are saying about back pressure from dense material that needs to be overcome for the trap to have the proper amount of fluidization.

However I do not agree with your assertion that tube clogging is an ongoing issue having never experienced it on my DIY unit in 1000's of hours of use over many years.

I also respectfully disagree with your idea that the "Tube Fluidization" method is "inherently flawed" and that gold loss issues will continue to plague the method.
It is my firm belief that those sleight gold loss issues can be overcome with a few tweaks in the basic design as my own experimentation and testing has proven. On average I achieve 95% recovery with peaks of 99% and lows of 90% depending upon varying conditions. Not bad for a fast feed rate with no classifying.

As a tinkerer and student of fluid dynamics, I am curious as to what % of gold loss would you say is associated with the "Fluid Dynamic Sluice" design based upon average conditions of flow and gold sizes and types as well as what effect varying rates of flow and angle have on those percentages?

Also what effect does feed rate and classification of material have on gold loss with the "Fluid Dynamic Sluice"?



GG~

 

[ProspectorJay]

"History is written by the victors" only applies when you're the last man standing.

Your Recon and Expedition sluices are hardly the latest evolution in fluid bed sluices. They've been on the market for several years now without any obvious design changes. You've never effectively addressed the issues that have been brought up by folks who have done extensive field testing in varying conditions, which is why in the vacuum surrounding the implosion of Bazooka I, and many others, have addressed some of the shortcomings of the Bazooka Gold Trap privately and now commercially. I've never seen someone build their own "Fluid Dynamic Sluice," unless you count the cheesy hybrids available from third world knock-off workshops.

Let's be frank, this is marketing disguised as a history. I'm happy to see that you're a supporting vendor now that you've changed the name of the company and your member name but you'll never be able to shake of the years of shade you've thrown without publicly addressing the very real concerns prospectors have brought up. Dismissal and historic revisionism isn't going to win you market share outside of a vacuum that no longer exists. A superior product will.

No one wants to classify material. This is why things like miners moss and Hungarian riffles have fallen out of favor for the traditional sluice market. It's all about throughput. Think less, shovel more. The math has been done, even by you, and it just doesn't work out for the weekend prospector to spend more time classifying and troweling buckets than shoveling unclassified material directly into a true fluid bed sluice.

 

[Goldwasher]

"The material throughput of the new sluice approach is about 85% of the current fluid bed design when comparing their relative sizes. However, there is a significant increase in the percentage of pay gold recovery which negates any material volume decrease. One last bonus of the Fluid Dynamic Sluice Design is that it is considerably lighter in weight and more compact in size making it much easier to carry. This allows prospectors and miners to travel more quickly and safely to their mining locations or provide the ability to test distant locations. With these advancements, true progress is moving forward. "

Man that last paragraph.......

No reason to promote Bazooka because it's gone and won't be back. So, my comments are based on use. I would love a sluice as an anchor product for my store can't get Keene...Bazooka gone, Gold hog and Grizzly gold trap don't wholesale and I just can't tell people to buy the AMP. Not to be mean not to make you angry I just can't promote what you say it does when it does not do it.

Sorry Todd but, the AMP does not keep up in production. Period regardless of the reason it works. A sniper, a Keene ran right or the new Grizzly gold trap runs circles around it. Through put is the name of the game and The Bazooka is way better than you are trying to describe it at running and holding gold. There is exchange in the trap a main riffle eddy even with out a real "riffle"

The new Grizzly gold trap had a lot of thought and engineering put into the design before release. I really look forward to field testing one. With all the choices out there and years of experience running sluice boxes. As a person who needs portability and a sluice that can be used in different situations the Amp just isn't on the list for me or any prospector I know who does significant stream sluicing.For production the AMP just doesn't cut it. It actually slows down production. The perceived increase in "efficiency" does not make up for the lack of weight in gold at the end of the day. Plus to get it's max capability you still have to classify. If classification is needed than a three foot stream sluice with 3/4" raised expanded over moss/v-mat/carpet just smokes the amp in through put and "efficiency". It is also more forgiving in different stream flow and placement.

Try not to get angry. It's better to listen and actually improve your product.

 

[Timberdoodle]

Kevin,
I don't want to come off to negative, but I do have some issues with the "history" you describe. First the Schmidt bazooka dredge was a tri-jet design and not a dual venturi. The 3rd jet is located at the outlet of the fluid chamber trap and helps facilitate material and water to leave the chamber once processed and keeps water flow through the trap. A grizzly was used at the front of the trap for material entry much like the current bazooka sluice. They actually worked very well for a subbie. Getting the right pressure dialed into the trap tube was important. Fine gold that makes it into the trap can be captured but the main problem was some fine gold does not settle fast enough to reach grizzly height after entering the dredge and out the back it goes.

The black magic was made with a wide scoop front to capture fast stream flow and convert this flow to pressure. If your saying that placing a sluice design like his into the water without any fast flow will not have a pressure differential because their is no pressure difference within the water I agree. This was designed to capture fast flow or be used on an angled installation like a normal stream sluice. Schmidt understood the fluid dynamics and was quite an engineer. People are still copying his original designs today. I don't believe the problem lies with Schmidt's understanding of how it works. It's a continual problem I have had reading your other posts on this subject.

A fluid trap design like Schmidts using tubes is one of the easiest ways to introduce downward flow into the material. This is one of the most important features in a fluid bed design for capturing gold. Sending material to the bottom of the trap provides action like a riffle vortex (gets material to the bottom and gold and other heavies resists the lift forces). If your trying to capture very fine gold any relying on it "settling" out in turbulent flow then your missing out on this important feature and missing gold. Anyone who has built and tested their own fluid beds and tried upward jet flow or side flow against downward flow will be able to tell you the importance in gold recovery.

The limit of a fluid bed sluice recovery is much like a normal sluice. In a stream sluice the riffle size and water speed creates the action for a given maximum material size. In a fluid bed the strength of the jet flow needed to keep material in a fluid state depends on the size of the material. As the strength of the jet is increased fine gold loss increases. Finding the right balance to material size, throughput, and recovery is where the bazooka excelled. Sure there are improvements that can be made to address velocity through the trap and other features, but the real improvement of using a fluid design is how fast it can process material and capture gold. The trick is to make recovery improvements without reducing throughput.

FYI-I have built and extensively tested many fluid beds over the years including Schmidt's original bazooka dredge design.

 

[SRP_KBell]

Goodguy –

Unfortunately the fluid bed design has the potential for clogging. It may not happen where you work or because you take necessary steps, but the potential problem exists. It has been brought up on this forum (see Do Bazooka Gold Traps pipes get clogged?)

I understand that by “tweeking” the design you can realize some additional gain, albeit marginal in most cases.

Angle is built into our sluice so it is not a problem – small variances do not affect recovery. Proper flow and speed is important in any sluice system and the Fluid Dynamics sluice is no different. In fast water conditions I place a rock upstream of the sluice and move it around until the proper flow speed is achieved. In slow water conditions I either create a rock wing dam to create velocity or setup the sluice in stacked or pooled water using a board as my “gate” and running water past the sluice.

I will tell you that the combination of strict input velocity, metered water and material entering the trap (the screen’s primary function is a limiter) and cross washing of material by the side plenums produces near perfect recovery capabilities down to 200 mesh while processing material at about 85% of the throughput of the original Bazooka of similar size. Recovery begins to drop off at 200 minus. BTW with increased classification (8 or 12 mesh) several of my customers in Washington get good recovery down to the visible range.

Classifying half inch or below nets excellent results and there is not much change up to 3/4”. Once you jump to 1” classification the water flow required to push that material through will easily carry 200 mesh gold and even some 100 mesh can get lost. Of course that is a factor of water speed not sluice efficiency.

I don’t run my sluice unclassified so I can’t speak from experience. KevinInC and GP Dave ran my sluice unclassified in a test against a Prospector (30” ?) done about two years ago. Kevin noted that both sluices recovered the same amount of gold and I believe he said the Prospector ran about 15% more dirt. So I believe it works with well with unclassified material.


Prosector Jay –

Yes you are right about us being on the market for several years but we made a very important design change in 2016. We added the trap partition which further slows the material - This allows better cross washing of the material and increases the drop time the of heavy material in the trap. This reduced the near perfect mesh size capture from 150 mesh down to 200 minus. Pretty significant change for a 17 cent piece of plastic.

Not sure what you mean by “You've never effectively addressed the issues that have been brought up by folks who have done extensive field testing in varying conditions…” or “…you'll never be able to shake of the years of shade you've thrown without publicly addressing the very real concerns prospectors have brought up”. I am more than willing to discuss anything in a public forum so feel free to address any issues you’ve heard or experienced directly with our equipment on this thread.

Goldwasher –

Production, throughput and gold recovery do not always go hand in hand. First, I agree classifying stinks and it sounds great in theory to be able to shovel directly into your sluice. However a couple of problems come to mind – First you are shoveling in a location that was best for setting up and operating the sluice not high concentrations of gold. In some cases you may get lucky and find good gold but the vast majority of the time you are digging marginal material.

I would rather find a large concentration, pocket or seam of gold, set my sluice up as close as I can and run high grade material by bucket. I normally classify to half-inch which goes pretty fast and I fill two or three buckets at once. Maybe a bit more work but now you are running only the best gold concentrations rather than accepting whatever gold is next to your sluice.

Bottom line: The argument that shoveling volumes of marginal material will get you more gold by days end than bucketing high grade material is weak at best.

Also when running material through your sluice with a shovel you cannot make the hole much bigger than about two foot around without having to taking a step to the sluice. As the hole gets larger or longer you now begin to need two or three steps – now it’s four or six steps round trip from where you dig to where you drop. Now direct shoveling begins to lose its value - At that point I’d say filling buckets becomes more viable. And if you’re filling buckets at least course classifying (throwing off the big chunks) would be a logical step, which of course takes time. I guess another option if possible, is to start another hole on the other side of the sluice or move the sluice to a better position.

 

[MadMarshall]

my two cents... is that anyone interested in gold mining is better off without your advice. your products your mining districts . pretty much anything you deal with in regards to mining...

 

[SRP_KBell]

Timberdoodle –

Yes the Schmidt Bazooka Dredge was a tri-jet design, but only two of the jets were used for the trap (one for each tube). You are correct about fine gold recovery – it is tough to capture fine gold when the water velocity and throughput is so high, especially in a dredge tube. Cool idea, even with its limitations.

As I stated before pressure at atmospheric is zero and having the sluice two or three inches under the water won’t change anything. You cannot use water velocity or volume to create pressure since compressing water doesn’t create pressure. The velocity of the water scoop stops, much like sticking a bucket with the mouth upstream – once the capacity of the bucket (or water scoop) is filled the incoming water will begin to flow around the bucket.

You will get minimal water entering the trap through the holes because water follows the path of least resistance, but as material packs around the holes any minimal flow will be reduced significantly. You are definitely right about the relationship between water speed and size of material, certainly as it relates to bringing the material into and through the trap. I am not sure how much impact it has on transfer of material captured.

In my opinion one of the main drawbacks of fluid beds is the trap operates at full capacity - sending material down to the bottom only pertains to material that was captured in the trap as the water and material passes through. There is virtually no room for material to fall and a very heavy force pushing very quickly towards the trap exit. This is a very similar problem to the Schmidt dredge – high water force and heavy throughput tend to drive the material straight out.

 

[Timberdoodle]

Timberdoodle –

Yes the Schmidt Bazooka Dredge was a tri-jet design, but only two of the jets were used for the trap (one for each tube).
Actually 3 venturi jets spaced 120deg out. Only one on bottom is fed in a closed pipe through the trap area to the outlet end of the trap. A fourth line with a valve was used to set the pressure to the trap chamber fluidization tube. If your trying to simply go off the patent drawings your probably making this mistake. I've seen a few in person.

You cannot use water velocity or volume to create pressure since compressing water doesn’t create pressure. Water velocity is used to create pressure that's how a centrifugal pump works!! water speed converts to pressure and water pressure can be converted to speed. basic fluid dynamics.

The velocity of the water scoop stops, much like sticking a bucket with the mouth upstream – once the capacity of the bucket (or water scoop) is filled the incoming water will begin to flow around the bucket. And the small water rise created in the bucket and at the front of the bucket in relation to the water outside the bucket is a pressure difference. Next time you go to the river bring a bucket and put a small hose in the bottom set it in fast flow and feel the flow output at the hose. How else do you think it works? You don't need much difference in pressure to fluidize the material if the tube locations, jet size, and distance is properly designed.

 

[SRP_KBell]

Timberdoodle –

What I was saying is you can’t use water velocity or compression to create pressure in the water scoop. A centrifugal pump has an impeller and other parts that create the pressure and velocity which is not relevant to the FB sluice.

Since the scoop is completely under water compression and water velocity is zero. Pressure is virtually zero, since it is at atmospheric. There is quite a difference between having a hose with no obstruction coming out of a bucket and capped off tubes with small holes being obstructed with heavy material.

 

[Timberdoodle]

True, The water velocity in the scoop is not creating pressure (even though bazooka website says so). The pressure differential is created in 2 possible ways.
1. The sluice is located on a down angle and the water height difference from the input of the scoop to the outlet of the trap induces the flow through the tubes.
2. In fast flowing water the area of the scoop creates a hydraulic jump in water height which creates enough pressure differential to induce flow through the tubes.
A hydraulic jump of 1-2 inches is all that is needed. Just look at the water difference in height as a fast flow goes over or around a rock in the river. The same principle applies, I think your missing this point. It does work and has been extensively proven.
In your sluice you are limiting the total water flow into the trap by using the punchplate and the outflow of the trap is sized to create a water draw through the side ports to create a side to side washing action. I'm sure it works pretty good and creates a multitude of dynamics in the chamber. I am pretty sure looking at your design that if the punchplate was replaced with grizzly bars that the flow into the chamber would be too great and flow would go backwards and out of the plenums.
Your approach is different for better or worse, but I simply want to point out that pressurized tubes do work very well and you are missing some of their important features if you keep thinking they can't work. The key is understanding the principles involved and why they do work.

 

[goldog]

I've been following this conversation today. Some interesting thoughts. I haven't used other fluid bed sluices but the Bazooka and similar sluices catch gold in my conditions.

Assuming the statements above are accurate, the math still favors unclassified material sent through at a higher feed rate. I guess there are some places with very fine gold. But for me the loss of some percentage of the minus 100 is more than made up in added volume.

To come on and try to tell each of us we're wrong and should use some newly made up advanced "dynamic" fluidbed is just bordering on silly.

There may be conditions where you can compete or even bury the competition. But I'll hold on to my Prospector or something similar.

 

[KevinInColorado]

I know from experience that both designs (yours and Bazooka Goldtrap style) work well, for the conditions and use they are intended to operate in. Kevin B I think it's bad idea for you to argue theory on why something shouldn't/doesn't work when clearly it does. The fluid bed tubes in a Bazooka DO keep the bed loose allowing gold to fall down into the matrix of material in the trap. Any theory that says this won't happen is just armchair noise.

Also in years and years of use (many hundreds of happy hours on four different Bazookas of my own plus friends I dug with), I've only seen a tube clog (get blocked really) twice. People worry about it but it's not really a thing that happens in the field.

Stick to highlighting the power of your design and the circumstances where it performs at its best and let the other brands speak for themselves. It was excellent results that led to the acceleration of Bazooka Goldtrap support here on tnet. Results speak volumes. Share yours (I know you have them!).

 

[Goldwasher]

Goodguy –

Unfortunately the fluid bed design has the potential for clogging. It may not happen where you work or because you take necessary steps, but the potential problem exists. It has been brought up on this forum (see Do Bazooka Gold Traps pipes get clogged?)

I understand that by “tweeking” the design you can realize some additional gain, albeit marginal in most cases.

Angle is built into our sluice so it is not a problem – small variances do not affect recovery. Proper flow and speed is important in any sluice system and the Fluid Dynamics sluice is no different. In fast water conditions I place a rock upstream of the sluice and move it around until the proper flow speed is achieved. In slow water conditions I either create a rock wing dam to create velocity or setup the sluice in stacked or pooled water using a board as my “gate” and running water past the sluice.

I will tell you that the combination of strict input velocity, metered water and material entering the trap (the screen’s primary function is a limiter) and cross washing of material by the side plenums produces near perfect recovery capabilities down to 200 mesh while processing material at about 85% of the throughput of the original Bazooka of similar size. Recovery begins to drop off at 200 minus. BTW with increased classification (8 or 12 mesh) several of my customers in Washington get good recovery down to the visible range.

Classifying half inch or below nets excellent results and there is not much change up to 3/4”. Once you jump to 1” classification the water flow required to push that material through will easily carry 200 mesh gold and even some 100 mesh can get lost. Of course that is a factor of water speed not sluice efficiency.

I don’t run my sluice unclassified so I can’t speak from experience. KevinInC and GP Dave ran my sluice unclassified in a test against a Prospector (30” ?) done about two years ago. Kevin noted that both sluices recovered the same amount of gold and I believe he said the Prospector ran about 15% more dirt. So I believe it works with well with unclassified material.


Prosector Jay –

Yes you are right about us being on the market for several years but we made a very important design change in 2016. We added the trap partition which further slows the material - This allows better cross washing of the material and increases the drop time the of heavy material in the trap. This reduced the near perfect mesh size capture from 150 mesh down to 200 minus. Pretty significant change for a 17 cent piece of plastic.

Not sure what you mean by “You've never effectively addressed the issues that have been brought up by folks who have done extensive field testing in varying conditions…” or “…you'll never be able to shake of the years of shade you've thrown without publicly addressing the very real concerns prospectors have brought up”. I am more than willing to discuss anything in a public forum so feel free to address any issues you’ve heard or experienced directly with our equipment on this thread.

Goldwasher –

Production, throughput and gold recovery do not always go hand in hand. First, I agree classifying stinks and it sounds great in theory to be able to shovel directly into your sluice. However a couple of problems come to mind – First you are shoveling in a location that was best for setting up and operating the sluice not high concentrations of gold. In some cases you may get lucky and find good gold but the vast majority of the time you are digging marginal material.

I would rather find a large concentration, pocket or seam of gold, set my sluice up as close as I can and run high grade material by bucket. I normally classify to half-inch which goes pretty fast and I fill two or three buckets at once. Maybe a bit more work but now you are running only the best gold concentrations rather than accepting whatever gold is next to your sluice.

Bottom line: The argument that shoveling volumes of marginal material will get you more gold by days end than bucketing high grade material is weak at best.

Also when running material through your sluice with a shovel you cannot make the hole much bigger than about two foot around without having to taking a step to the sluice. As the hole gets larger or longer you now begin to need two or three steps – now it’s four or six steps round trip from where you dig to where you drop. Now direct shoveling begins to lose its value - At that point I’d say filling buckets becomes more viable. And if you’re filling buckets at least course classifying (throwing off the big chunks) would be a logical step, which of course takes time. I guess another option if possible, is to start another hole on the other side of the sluice or move the sluice to a better position.

Kevin I don't sluice because I'm hoping to get gold.Once we sample a out a spot we strip run overburden "marginal material" Then run the pay layer the fastes most efficient way I/we can.

When I'm by my self which is the majority of the time I can't stop doing one thing too often or efficiency drops. You can most certainly set up and dig a whole day withing a two to four step shovel radius.

At no time am I accepting "the best gold next to my sluice" My sluice is close to and i'm running gold from a pay streak or concentration. I'm woking a perenial stream most of the time.

On the river it is easier even to find the flood layer if you want to shovel and sluice. River or creek 40% of my gold atleast comes from cracks shovels cant hit so it's in my snuffer anyway.

The fact remains that you can't escape....the smaller a sluice is the less productive it is and the more loss of gold it has at max feed.

Your sluices are the smallest available, you "have" to classify even though they have a classifier , you have to clean out often because there is a lump of inactive material in the trap, the plenums are a pain in the but to deal with in low and moderate flow.

Smaller is less productive just the way it is.

I never said I never classify. That I always run where I can shovel right in or that I never carry buckets. Even so in any of those situations I am not seeking out the AMP to increase production or efficiency cause it just doesn't do it.

I'm not arguing against sourcing the best material that.s a given. Still, if I have flow a Keene with low profile recovery or a drop riffle or a gold hog stream sluice will produce more gold at the end of the day than a box that will be buried by two shovel loads.

Don't put too much of your sluices abilities against how material is sourced and carried to the sluice that was not the point I was making.

I actually made some videos yesterday showing how good just seven inches of deep v-mat is at catching and holding gold. Heading out to roast again today I'll try to post videos later.

In the mean time if you want to tout production make a better sluice. If you want to sell your entry level sampling sluice more often, come up with better marketing and describe it more accurately.

 

[SRP_KBell]

No one, including myself would disagree that the fluid bed design catches gold – What I am saying is there are limitations to the design as stated above - My goal with the fluid dynamics system was to address and overcome these limitations and create a compact, lightweight sluice that was easy to carry, had excellent throughput and recovery capabilities and met and exceeded the needs of the average miner without limitation.

GW – I realize that daily miners like you who are making a living or supplementing household income need the highest level of production. I have no doubt you are extremely good at reading streams, finding pay layers and running material by whatever means necessary to recover gold. I am sure you are running material 4-6 hours a day or more and spending much of that time shoveling, so in your case the running volume argument is plausible. However, I doubt that argument holds true for the vast majority of prospectors and miners who are not daily workers - they pick a place that looks good, make sure the sluice runs fine, take a couple of test pans and then have at it, whether by shoveling or by bucket.

I talk with hundreds of miners during gold shows and other events and these folks are not shoveling for 4-6 hours - They rarely run more than 15-20 buckets a day which means they dig about a yard of material. Once there is a limitation of material the argument of maximum throughput or production is no longer plausible. In these situations, efficiency of recovery wins. Classify to concentrate the material and run it in the most quick and effective means that doesn’t affect the efficiency of recovery.

 

[Timberdoodle]

I hear what your saying Kevin and I do know how hard it can be to introduce a new product that employs new ideas. I just had a hard time reading your introduction into the history of fluid bed designs and especially when you say Schmidt's designs failed and basing that on a misunderstanding of the dynamics involved. I have spent the past 2 winters working on fluid bed designs so I have a very good grasp of the subject matter. The very first rule of a fluid bed design and why it was so successful is the ability to quickly feed it and get good recovery without classifying. It is why people want to use them. The second rule is making sure you meet the first rule. I think every bazooka sluice could be set in the best flow and fed classified material and achieve much better recovery than just shoveling into it in fast flow, but that negates the purpose of why people want to use them. Overcoming some stated limitations by introducing other limitations is not what I consider evolving. Your onto something if your getting recovery like your stating, but please take it to the next level before claiming a better product.

 

[N-Lionberger]

I think the Schmidt bazooka dredge design is pretty cool, I built my own from ABS. As far as subsurface dredge recovery on fines goes its a winner as far as I can tell as subsurface dredges are really bad at retaining fines, I have to disagree on the comment about it having to be at a certain angle while this is true in a conventional subsurface is not the case with the Schmidt design. So what I am reading from Kevin's last post there is that the AMP sluice is a toy designed for hobbiests?

 

[Goldwasher]

No one, including myself would disagree that the fluid bed design catches gold – What I am saying is there are limitations to the design as stated above - My goal with the fluid dynamics system was to address and overcome these limitations and create a compact, lightweight sluice that was easy to carry, had excellent throughput and recovery capabilities and met and exceeded the needs of the average miner without limitation.

GW – I realize that daily miners like you who are making a living or supplementing household income need the highest level of production. I have no doubt you are extremely good at reading streams, finding pay layers and running material by whatever means necessary to recover gold. I am sure you are running material 4-6 hours a day or more and spending much of that time shoveling, so in your case the running volume argument is plausible. However, I doubt that argument holds true for the vast majority of prospectors and miners who are not daily workers - they pick a place that looks good, make sure the sluice runs fine, take a couple of test pans and then have at it, whether by shoveling or by bucket.

I talk with hundreds of miners during gold shows and other events and these folks are not shoveling for 4-6 hours - They rarely run more than 15-20 buckets a day which means they dig about a yard of material. Once there is a limitation of material the argument of maximum throughput or production is no longer plausible. In these situations, efficiency of recovery wins. Classify to concentrate the material and run it in the most quick and effective means that doesn’t affect the efficiency of recovery.

Maybe they work an area roughly a yard in size. Thirty four buckets ( FULL) through a run is a yard.

To the rest of your remark.

You just totally contradicted your own marketing.

Basically if you made something guys who do dig like me would use. You would sell more of them. The Amp is slower than a three foot stream sluice running classified and it is not more efficient at catching gold.

Coming out and touting as something that is going to innovate small scale mining is pretty bold. It's the sort of thing that really the end user is supposed to let you know you did....just sayin'

 

[Goldwasher]

I'm at ninety days on the claim since it started raining. Would be more like one twenty but there were days where it was just too rainy and the water too high to really get much done.

I have had to deal with every water condition you can imagine. From getting enough water to run 1/2 inch classified to trying to just intake enough into the sluice run, because there is so much.

Because of the overall nature of doing this by hand and mostly alone I cut every corner I can.

If your digging your not running...if your running your not digging.

I do try to set up as close to the source as possible. Fact I'm digging what I would love to hit with a four inch and could so I'm working an in stream deposit i's a no brained that I can be shovel close.

Just like the old timers you move up following the pay your tailings fill holes behind you.

So, here's the secret!!!

Gold and I mean the main bulk of ALL of it gets caught in the first damn thing it can get caught in.

Of course you want to try and limit scour and turbulent water.

At the risk of dropping some jaws or even being accused of being full of it I'll share a little.

I have twelve feet of sluice on the claim. I'VE NEVER found gold or lead past foot six.

I have a knock off stream sluice that has deep v mat in it. I run it bare with the exception of the v mat to build up speed and feed the next sluice. Wether I like it or not sluice two is a safety sluice.

The gold including talcum fine powder just doesn't even make it past the first matting and I am not losing it in my tailings.

I do get a little gold in my second sluice thogh if my first sluice is expanded over moss I get just a few specks.

Yesterday was the same. Though in #2 there was this tiny little course piece of gold/sand.

I get great recovery and throughput using what many will try and tell you is out dated and inefficient.

I beg to differ.

 

[ProspectorJay]

My goal with the fluid dynamics system was to address and overcome these limitations and create a compact, lightweight sluice that was easy to carry, had excellent throughput and recovery capabilities and met and exceeded the needs of the average miner without limitation.

You don't get to determine the needs of the average miner, they do. Forcing classification is a material limitation if a miner's calculus doesn't include it.

However, I doubt that argument holds true for the vast majority of prospectors and miners who are not daily workers - they pick a place that looks good, make sure the sluice runs fine, take a couple of test pans and then have at it, whether by shoveling or by bucket.

You're marketing to below average miners, beginners who don't have all the information they need to perform their own calculus. I can only assume that's what you're trying to provide with your marketing material (read: alternate history and facts) in order that you might prevent them from discovering the flaws in their equations.

I talk with hundreds of miners during gold shows and other events and these folks are not shoveling for 4-6 hours - They rarely run more than 15-20 buckets a day which means they dig about a yard of material. Once there is a limitation of material the argument of maximum throughput or production is no longer plausible. In these situations, efficiency of recovery wins. Classify to concentrate the material and run it in the most quick and effective means that doesn’t affect the efficiency of recovery.

Your own math, done previously in another thread, doesn't support your claim:

I stated the AMP (which I never intended to get in this thread) can run a 2 gal bucket of classified material in 42 seconds. Now leave classification out of the equation. If I take a 2 gal bucket of unclassified material and pour it through the machine it will take less than 42 seconds because the amount of material actually going into the machine is less. You stated you could pour a 5 gal bucket of unclassified material into the Bazooka in 90 seconds (1.5 minutes). I stated that I could run the same 5 gal bucket of unclassified material in 105 seconds (1.75 minutes). Yes that means the AMP could only run 85% of the material of the Bazooka in the time period of 40 buckets (The AMP could only do 34). Then I stated if the Bazooka is 90% efficient and you get 4 grams in 40 buckets, the AMP runs 34 buckets @ 98% efficiency or 3.67 gr. This is unclassified material. The difference is .34 grains

But everywhere you state that to get to 98+/-% efficiency you have to classify. You always leave out the effort involved in classification. I don't know about you, but classification and moving buckets is backbreaking labor. It is significantly more work, as proven by the evidence of my own experience, than shoveling directly into a sluice while standing upright. Efficiency of labor is more important than .34 grains less at the end of the day.

I have never said publicly or in these or other posts that I think my machine is better - My machine is different. Do I believe my machine is more efficient? yes. Do I know the Bazooka can process more material? yes. Is the actual gold recovery between the two machines that different? no.

Yet even with your own math, the average miner is going to have more gold in his poke at the end of the day using equipment other than your own with less energy expended. If you don't have the conviction that your machine is better for the average miner than what motivation is the average miner going to have to buy your product?

I honestly think you're marketing your sluices wrong. If you were paying me to market it I would sell it not as competition to production sluices but as a sampling sluice for the beginner who doesn't like to pan. Every month there's a thread in this very forum where someone asks about how to sample without a pan. I think there are enough recreational miners out there that don't have the motor skills necessary to pan overburden effectively and your sluice could be marketed to give them the confidence that they're capable of doing solid test runs to find the pay streak if they're willing to shell out. A good video series to this effect showing how much easier it is to pan the cons your machine produces would probably prove it out and empty your shelves.

Don't try to rewrite history and hand-wave away the complaints "above-average" miners have with your comparisons, you're just generating ill-will amongst those who know better. Focus your marketing in the right direction.