GoldSnare SGS-2

[coolfinie]

Has anybody used one of these, particularly for fine (50 to 200 mesh) gold?

I read that the original suitcase subsurface dredges worked but were prone to let fines go out the back due to a short bed and turbulence, and I'm wondering what makes the GoldSnare different from those earlier types.

I've been considering trying electric for dredges, and not having to lift the material to the sluicing area makes sense for reduction of power required. But those old reports bother me and there's not that much information out there yet for the newer type..

 

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[KevinInColorado]

Brian053 has one and can tell you about it. He let me run it for a bit last time we were out together.cool tool.

Also you can search this site/forum for Goldsnare and gold snare (with the space) to find more reviews from the last couple years.

Good luck

 

[triple d]

I believe it was designed for that purpose. To catch fine placier gold.It was made and tested in Maine. And most of the gold is very fine. In that area.

 

[mytimetoshine]

To my knowledge there really isn't anything out there electric that really will get the job done. Although someone posted a promising DIY prototype not long ago.

 

[triple d]

The sgs two can be run with a gas pump also. A small honda or a pump of that class and type. Visit the gold snare web site. It explains the options.

 

[brianc053]

Hi coolfinie. Kevin mentioned that I have a Goldsnare; I've got the SGS-1, the little brother to the SGS-2. Here are my thoughts on both:
- the SGS-1 performs as-advertised and in the right situations I've been very happy with it. It catches fine gold; I'm not 100% sure how it does it effectively while past underwater designs have failed, but I believe (from the Goldsnare website and also from private email exchanges with Rob the designer) that the hard work Rob put into the design of the "gates" coupled with the proper water velocity and the matting he uses allows the device to catch the fine gold (I've recovered 50-100 mesh stuff for sure).
- I said "in the right situations" about the SGS-1 because it doesn't move a lot of material. That should probably be assumed anyway with a 1 inch, electric pump device but I thought I'd say it explicitly. I've found a few places where I could pull gravel off bedrock depressions and out of cracks, using a screwdriver to pseudo-snipe the stuff out so it could be sucked up, and that worked best. In a few spots where there were more than a few inches of "overburden" I should have shoveled first. I'm learning... I will also note that it's pretty easy to clog up the 1" nozzle, and because it's an all-in-one unit you're not just working a nozzle like a real dredge; instead you're moving the whole device around, so I often wish I had 3 or more hands because keeping the nozzle free while moving the device around is challenging. I'm considering some mods that include adding a second pump and a longer, more flexible hose. In consulting with Rob he thinks it would work. If i do it over the Winter I'll post pics.

- As for the SGS-2, while I don't have practical experience I can confidently say that the box itself should catch gold since the SGS-1 box works well, and while the designs are a little different the designer - Rob - is the same and I trust him. The ability to open the SGS-2 box would be beneficial. The fact that the SGS-2 has a flexible, longer hose would also be a big benefit.
- As Triple D said, you can power the SGS-2 with a gasoline pump (recommended) or with a 12V pump (not really recommended, but could work - you'd have to have the whole box underwater, and in some locations that can be a challenge).

I plan to use the SGS-1 more in 2016 in some known bedrock areas both up in New England and down in Virginia. More to come from the field...

- Brian

 

[coolfinie]

Thanks very much for the helpful replies!

I'll bet that mass battery production for electric autos and brushless motor water pumps will definitely push the boundary upwards quite a bit more in the very near future.
I expect those water pumps are all the older brushed type of motor and a lot of power gets lost as heat.
An 88% efficient brushless water pump would consume the same power as a 55% brushed motor water pump, but push 60% more water.
Imagine a 3" diameter brushless electric Goldsnare for the same battery size!

 

[mytimetoshine]

Yea we need to get Tesla to make us a real water pump that can run off battery. The technology is definitely there. Just not being applied to what we are doing.

 

[Oregon Viking]

Thanks very much for the helpful replies!

I'll bet that mass battery production for electric autos and brushless motor water pumps will definitely push the boundary upwards quite a bit more in the very near future.
I expect those water pumps are all the older brushed type of motor and a lot of power gets lost as heat.
An 88% efficient brushless water pump would consume the same power as a 55% brushed motor water pump, but push 60% more water.
Imagine a 3" diameter brushless electric Goldsnare for the same battery size!

Yep!
I have owned brushless RC motors, powered by lithium batteries. Very efficient and powerful.

 

[coolfinie]

Roughly speaking it seems that one horsepower per inch of dredge diameter is required when using gasoline engines to run the pump.
Since a horsepower is 750 watts, that's the same as 750 watts per inch.
but that's the power we put in, not the amount of work done.
So if that gas pump were to be, eg 60% efficient, (the rest being lost as heat out the exhaust and off the cooling fins on the engine)
then for say a 3 inch dredge, 3 x 1hp = 3 x 750W = 2250 watts, or 2 1/4 kilowatts.

But if a brushless pump were 85% efficient, which is no problem, 90% is available off the shelf (in BL motors)
then we get
2250W with a 60% gas engine implies the actual work done is 1350 watts of work for the 3" dredge. We can call this 1350 watts out,
and if we have an 85% efficiency power unit we need "only" have 1350 / .85 which is 1588 Watts in with the brushless pump.
.. and that leccie version would do the exact same work at the 3hp gasser.

So 1588 watts in using a 10 cell lipoly battery of 37V would run at 1588/37 = 42.9 amps which is a reasonable current.
The reason to step up to 37V is to keep amps down and cost down.
But if we leave it as a 12 volt system, then 1588/12 = 132 amps which is extremely high for constant running.

So for an hour 43 amps is required to match the gasoline.
For 4 hours that would be 4 x 43 = 172 Amp hours at 37 volts
and that's where the electric comes a cropper, because that's an big expensive battery - a 200 Amp 12V battery in lithium would be $2000 plus.
I don't know what a 200 amp hour 37Volt battery would cost!

So it's clear that where we waste excess gas power without being unduly concerned, electric must exploit all power reduction tricks, like shortening the suction tubes, bringing the dredge down to the material rather than lifting the material to the dredge, aiming primarily at the smaller diameter dredges in the first place, short duration sessions, and so on.
If you do that you get into rechargeable low cost operation with electric and stop buying gasoline.

The first thing I would mention is that electric brushless is amazing at delivering torque, something which two stroke engines only do when revved right up high. Four strokes are more torquey at medium range rpm, so brushless compares better with 4-stroke than with 2-stroke in operation.

The next thing is that as engines reduce in capacity, gasoline engines tend to hit a minimum design weight and then stop getting lighter. It takes metal to contain the vibration and distribute the heat. But electric gets smaller as the size reduces in a much more linear way, so small equals light and compact in EP but not so much in GP.

This might be a long winded way of saying that (based on the way I look at these things) the Goldsnare could be the beginning of a new niche retail dredge market (small size) which was previously only available to DIY builders. Also the smaller the diameter of the dredge, the more future versions will be electric due to weight advantages. So for sniping, definitely.

And if Tesla and the European electric car makers get their acts together, we should see 2 1/2" become viable for electric within a reasonable time period. Until then 2" appears to be a practical limit based on cost of power.

But that doesn't mean it can't be done right now already. A gas powered generator can easily provide a couple of KW which can be sent by cable to an electric dredge. No expensive batteries required!
That would put the dredge on a power tether (power cable) with the pump located at point of use. That would be far more flexible than the current arrangement with the gas pump tethered to the dredge by water bearing hose pipes. So electric, in gas generator electric pump hybrid style, is a lot closer (in bigger diameters) than folks might think.

 

[Timberdoodle]

Nice write-up Coolfinie!
I'm the guy who designed and builds the Goldsnare's. I was faced with many of the issues you mentioned creating a small electric dredge which is how these designs were initially intended for use. I had to build my own jets to get the best efficiency and solve the submersible fine gold problem to make it work. The 1" dredge is a very good match for electric, but having run my 2" dredges for the past few years, I definitely lean to using a gas pump in most situations since they can provide the most power vs weight carried in and allow for a more versatile system in the field. For now I only recommend an electric 2" for those who are restricted to electric only in certain areas of the world. Until the costs go down on the lithium batteries I have a hard time justifying the expense and battery runtime vs what a small gas pump can do. Hopefully that's not far off and combining some of these batteries with a brushless motor and pump will be financially feasible and more portable.