Bazooka Setup Questions

[Skiddum]

that's sweet I'd like to see it. what size ball bearing where they say mesh size. like some good buck shot size or bigger. it'd be just like having some good gravel. and gold washer. the only reason I preload Mt bazooka is just because I'm cautious. I figure if it's already set then I shouldnt loose anything when I start.

 

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[Hard Prospector]

that's sweet I'd like to see it. what size ball bearing where they say mesh size. like some good buck shot size or bigger. it'd be just like having some good gravel. and gold washer. the only reason I preload Mt bazooka is just because I'm cautious. I figure if it's already set then I shouldnt loose anything when I start.

I have no idea the size of the ball bearings he used in the fluid bed trap but it looked like a 1/4" classifier inset into a the 5 gal clean- out bucket he dumped the Bazooka into. The bearings were clearly larger then the 1/4" screen that caught em and I was curious my self but it was getting dark and the guy was cool not minding me hanging out and watching his program so I thanked him for the tip and split.

 

[ConceptualizedNetherlandr]

I can see the ball bearing being a good idea, especially that they are round and less likely to jam up or lock together. Might just be the ticket to keeping things moving.

 

[arizau]

Marbles. Many different sizes readily available including the ones for flower display vases or just borrow some from the kids or grand kids.

 

[KevinInColorado]

Marbles are not nearly as dense as good quality ball bearings...would that matter?

 

[arizau]

May move around easier to keep things loose and will displace up as heavies settle. I plan on using them since I already have a supply. Probably equivalent weight to same size stones.

 

[ConceptualizedNetherlandr]

marbles are glass = quartz ....and .....goodbye marbles

 

[ConceptualizedNetherlandr]

Let us know when you are finished so I can be the first to say 'you lost your marbles '

 

[Hard Prospector]

I was thinking about stainless steel ball bearings which are heavy and would stay uniform

 

[arizau]

Hmmm. Lets see now. At the end of a run using only bank run feed (no preloading) the only thing left in the box is what? Seems like it was a combination of sizes/weights up to a maximum size of about the grizzly opening (in my case about 3/16") and various sized quartz pieces were part of the mix the last time I checked. Seems like a 1/2 - 9/16" marble weighing 4.5 grams (yes, I weighed one) would stay home just as lesser sized pieces of quartz seem to do. There may be a crowding effect, especially in a severely angled box, that may force them up some but I'm not sure to what extent. That same crowding will effect ball bearings and the use of smaller ball bearings leaves less gap volume than with any larger media. Remember, the bearings will likely stay tightly compacted. Any resulting smaller volume of open area may and probably will inhibit exchange and settling when you think about it.

A little more food for thought: What are the other possible variables/effects when I preload rocks, bearings or marbles large or small? What effect will the induced water from the tubes have on previously settled lights now covered by preloaded media? Will the heavy media actually impede stirring/exchange of them? Kind of makes my brain hurt.

Possible solution - Your choice. Add media or just feed it as it was designed, let it eat and accept the fact that in either case it will still not be 100% efficient down to the last possible color just as are all other sluice designs. At least you don't have to classify!

PS: Marbles were offered as a convenient alternative not a solution. Funny comments though.

 

[ConceptualizedNetherlandr]

What you have to consider is that even though a few pieces of mostly quartz like density materials may remain when you shut down, (probably the most recent in) yards of the stuff has passed off. Put 100 marbles half inch marbles in, run a yard of material, and I'd bet a thousand dollars you don't have 2 marbles left in there.

 

[arizau]

For the sake of illustration: a 5x5" box area 25" square for a capacity of 100 1/2" spheres 1/2" tall. The next level will be 81 spheres which will naturally nest in the voids between the bottom layer and will be less than 1" in total height (maybe equal to the available space below the bottom of the tubes?). If you work at it you may be able to add 100 but that is stacking bb's. In any case the open voids between the spheres are less than grizzly opening size. There is no room for lateral movement for the bottom layer but the second layer may be mobile depending on the makeup.

Water is introduced (under pressure and from above the spheres) via the tubes. Some lateral movement of the upper layer may take place but the bottom layer stays stable as there is no place to go but up and there is no real influence to encourage this. Water under pressure does not compress but it does displace surrounding water to where it can go (that is upward in this case) and that is what creates the fluid bed sorting.

Water is introduced through the grizzly opening and immediately seeks the path of least resistance and that is the exit port. It meets the rising water from the box and more water displacement takes place and that is partly backwards, causing a boil at the entrance, but mostly towards the exit since there is less resistance. When feed material is included several things happen. Some materials seek the bottom, others become suspended in the upper layers of the fluid bed before they are swept out by the current while others just flush out the exit port. Little or no exchange takes place unless there is new feed being introduced eg. water entering through the grizzly entrance does not cause the exchange but newly introduced material and up currents do. This is seen when looking through the exit when the sluice is idling.

Added material fills in the voids among the bottom layer spheres first and pretty much becomes a packed bed since the spheres are locked in place dimensionally and by weight. There is little to no stirring and up-flow of water to loosen them and the other settled material. The second layer will be filled up and there will be some stirring and exchanges taking place. The second layer spheres are bullys at this time having size and most likely weight advantages over other settled material thus mostly limiting the exchanges to material smaller than the spheres. The up currents will not lift the second layer spheres but they will cause them to move around a little. At extreme sluice angles and perhaps flow some of the marbles may be displaced upward and exit but many will be in a mostly packed and probably not active bed in the crease at bottom back of the sluice.

The science can be tested, as Kevin suggests below. I'll do mine later this year since there is no flowing water here until the usual mid July monsoons hit.


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[KevinInColorado]

I think it would be great fun to run an experiment or two and I hope someone does. I'm already happy with how my stock box works so it won't be me though.

 

[arizau]

See my edited post above.

 

[arizau]

I think it would be great fun to run an experiment or two and I hope someone does. I'm already happy with how my stock box works so it won't be me though.

Not unless you want to test some more of that wicked ocean beach sand.

 

[Goldwasher]

Funny thing is when the Bazooka goes in the box it doesn't come with a bag of ball bearings or Marbles I have a feeling a shovel and a gold bearing area are the only other things required to make one work effectively..... But, I'm no Bazooka expert or anything

 

[ConceptualizedNetherlandr]

Save the larger non gold size fraction of your previous runs, start with that, only better stuff will replace it.

Anybody still have their marbles?

 

[KevinInColorado]

Save the larger non gold size fraction of your previous runs, start with that, only better stuff will replace it.

Anybody still have their marbles?

That is what I often do too. Toss the panned out material from my prior cons in the sluice before I start shoveling. I figure any gold that escaped my finish panning has a second chance at getting into my bottle that way! Btw, this does NOT include the super heavy stuff - black sand, garnets, etc. - that gets dried and saved for further processing...I just mean the cons that come home but are less heavy than the black sand.

PS no, I lost my marbles long ago

 

[DizzyDigger]

You fellows are discussing exactly what I've been thinking, except
in much more technical detail. My method is more of a "let's try this
and see if it works" approach.

I've got enough 1/2" ball bearings to cover the bottom of the fluid
bed in a Bazooka, and was thinking that would make a safe place
for all the fly and flea poop. With all the eddy currents going through
the ball bearings, there should be ample room for the fine gold to get
protected from being washed out.

Now I just need to sell my Gold Cube and get the Bazooka...

 

[GoldpannerDave]

OK, so I got a chance to take out my new Bazooka prospector (36") this weekend, and I was surprised at the problems I had with it. The creek I was in had plenty of water, so I don't think the flow was an issue. First off, it wants to pop up and float away. This hasn't been an issue with my traditional sluice, its got bars to put a rock on and keep it in place. But the bazooka is like 8 or 9 inches deep and needs to be pretty much fully submerged. This proved to be difficult to setup. I had to pile a lot of rocks around and over it.... So after getting that worked out, I worked to find an angle with the flow that would clear the rocks. I eventually sorta got it working, but still had to clear them by hand every scoop, or maybe every other at most. Should it be self clearing the rocks easier? Then on top of that, I wasn't really convinced the fluid trap was working as intended. I could stick my finger into the trap, but it wasn't exactly 'fluid'. After about 45 minutes of shoveling it definitely seemed to have locked up on one side. When I got my concentrates home I ran them over my Angus Mackirk then panned them. No gold, very very little black sands at all, like almost none. Now I was in a new area, so I can't comment about how much gold I was expecting to see, but it is a productive spot for some people, so I was expecting to see some form of color. I did do some test pans before I setup, and had found a flake in the area I was digging in. Most of the cons seemed to be blond sands and there were a lot of bb sized rocks. Since I was underwhelmed with the fluid bed performance, I started examining the tubes in the fluid bed. I can't feel any holes on the bottom, or see any. But I also can't reach all the way around the tubes. For other Bazooka owners, can you see or feel the holes in the tubes in the trap? I'm really not sure how I set it up wrong, I think maybe a steeper angle might help the gravels clearing, but I don't think it would have done much more to help the fluid trap section out.. Anyone have any ideas? Questions? Similar or different experiences? I've heard so many good things about these sluices, with very little negatives being discussed, so I had high expectations I guess..

Holding in place, you can use long spikes or just a long piece of rebar pounded into the stream bed. My Bazooka has a handle on one side, so I can put a spike thru it and wedge a rock on the other side or another spike. I will read the rest of the thread before commenting anymore on your problems.