Continuing the learning experience with my dredge/highbanker combo, observations/q's

[matt_unique]

I just completed my 2nd outing with my 2" Keene dredge/highbanker combo using a Honda water pump pushing just under 10,000 GPH.

After my first outing I got rid of my heavy "flexible" hoses that I had used for the clear water suction portion and the clear water discharge portion to the nozzle. These hoses were anything but flexible, heavy, and a pain to carry/store. I replaced these hose sections with the slurry hose I use going from the nozzle to the dredge (Keene's actually flexible rigid hose). During my last outing I punched a hole 3 feet deep over about a day and a half. Over the last few hours at the 3' mark the Keene hose (the clear water discharge portion going from pump to nozzle) started springing leaks every 15 minutes. I did not have a single leak for the first full day, so either it was a wicked coincidence or the 3' depth/pressure change was more than the Keene flexible hose could handle. I tried duct tape but the water was piecing right through that too and shooting 8' in the air. There is a lot of pressure in this section of hose of course because the 2" hose is reduced to 1.25" at the nozzle. So one lesson learned here is I have to revert back to the heavier duty hose for the pump to nozzle portion if punching holes more than about 2' deep.

One question I had was about the system getting plugged with rocks and the resulting water surge when cleared. 99% of them occur in the nozzle of course and a stick clears about 75% of those. The remainder require me to shut off the pump, remove the hose clamp/hose from the nozzle, and clear the plug. Maybe twice over the course of a day a plug occurs where the slurry discharge hose meets the highbanker. My concern is that for all plugs the water flow rate is reduced and then it of course surges when cleared, possibly blowing out any gold in the sluice. How do you guys contend with that? Do you climb out of the hole with every plug to shut off the pump, clear the plug, and then slowly increase the water flow rate?

I have found gold with each outing using my rig. My first outing had nothing but flour size gold (but perhaps 100 pieces). For my most recent outing I had maybe 10 pieces of gold (ouch) but two of them were considerably larger than the flour size I usually get (see pic below) and interestingly all from the first day/shallower depth. I did not find a single spec from my 2nd day (half day at the deeper depth) which is very odd. Size is relative, and I'm still talking about flakes that are picked up with the end of a wet toothpick and dropped into my vial, but still larger than the usual size I get. I use a Gold Cube to process the 1/8" classified sluice concentrates and then I pan the super concentrates. Specific gravity logic would suggest if I am catching flour size gold I would be catching anything larger/heavier, but larger/heavier gold also has more 'windage' so to speak and I wonder if my flow rates/sluice angles are optimized. Based on the suggestion of Buddy I decided to bring home 5G of my sluice discharge to see if I find any gold. I have yet to process that material and it will of course be telling as to whether I have things setup right.

One other question I had is how you guys suggest processing the larger (>1/8") concentrates? Maybe I am fretting over the small stuff when I have nuggets sitting in my buckets at home (ha ha - not likely). I take my 1/8" classified material and classify that through a 3/8". I visually inspect the >3/8" material and then toss in the rock walkway at home. People do find nuggets in Maine though and I want to be sure I am processing the larger material correctly.

I have decided I hate panning. I panned for 20+ years, moved to a sluice, and then this year moved to my current powered rig. I have found gold in the Swift River every single time I have gone since my first outing at 10 when I took a 1-day class through a local college. I would rather dredge for 8 hours than pan for 20 minutes. I used to use a Black Magic miller table for the last few years but in my experience it's not much easier than panning (takes just as long, spend as much time hunched over with a sore back, etc.). Maybe I need a refresher but it takes me forever to pan out a cup of super concentrates. Perhaps I am being too careful/taking too long with the final portions. Anyone share my disdain for panning? Ha ha - if yes - what solutions/products do you use?

Thanks

 

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[rodoconnor]

Matt, panning can be bone numbingly boring. A cup of super cons isn't much to contend with . You might consider a blue bowl. Probably a bit faster than a table, Get some classifiers 20 , 50 ,100. You'll be amazed at how much Au you might be missing. G/L

 

[arizau]

I agree with rodoconnor about the screen classifiers. For everything smaller than 20/30 mesh I pan in small quantities of about a tablespoon or less at a time. That goes pretty quickly and it also makes it hard to miss anything except maybe in the -100 mesh material (much of the ocean beach gold that I mine is much smaller than 100 mesh). If you are afraid that you are missing some then save the rejects and process them with the table or bowl on one of those cold winter days.

Good luck

PS: I speed pan all oversize too and it is extremely hard to miss anything over 1/8".

 

[principedeleon]

You dont want to be dredging more than 2 feet with a 2" dredge specially with a suction nozzle jet .. with a biggier dredge you will punch 2 or 3 holes that big in a day .. just a couple of pounds more to carry but you will have a better chance to sample where bedrock is between 3-5 feet ..

 

[brianc053]

Matt, regarding your question about plugs and the resulting surge of water into the sluice: I've had that same concern - you're not alone. I'm in my second year of dredging, so I'm no expert, but my opinion is: just clear the plug as fast as you can and get back to dredging. I've stopped worrying about any gold that might get blown out of the sluice; I feel I'm getting most (maybe all) of it home with me. Whatever I blow out of the sluice is left behind for whoever dredges the hole next time.
I actually don't think much gets dislodged; the typical opinion is that once the gold gets in the box it stays in the box. There are probably experts who can explain when that "typical opinion" applies and when it does not.
And another thought: most of the best gold is high up in the box, so even if it gets moved down a little by a blowout it probably doesn't leave the box. Again, experts are welcome to chime in - I'd love to know whether my understanding is accurate.

Good luck out there!

- Brian

 

[Hoser John]

Flex hose is a pain and thicker CLEAR kanaflex 151 last about forever if kept/stored out of the sun during winter. Plugups easily removed with a steel conduit pipe the length of your hose. Put your highbanker as close to,or even in, the water as with a suction nozzle the suction doesn't get near as good than with a powerjet. SLOW DOWN as you yourself have just explained all the time, effort and energy expended playing with plugups is a 100% waste of time. By slowing down you instantly get MUCH more gold. Expend much less energy and time so you can dredge longer. You did NOT mention a blaster nozzle as they are the most important tool to dredge as them cracks and crevices hold way over half the gold in the majority of situations. Use a 3/4 " garden hose,el cheapo control valve and a righteous hi pressure lawn sweeper nozzle and the clay will melt like butter, the impacted gravels will dissolve and then the deep cracks will give up their glorious bounty. Work smarter and NOT harder. Tons a au 2 u 2-John

 

[matt_unique]

Thanks for the suggestions.
Hoser and others, what do you do when you get a plug up? Clear it and keep trucking even though there will be a water surge in your box or climb out and shut down the pump each time?

I processed 5G of tailings and only found one piece of fly poop size gold. I dug these tailings on day 2, and I found nothing in the box day 2. All the gold I found was from day 1. If I found lots of flakes on the tailings I would be more concerned of course.

The Blue Bowl carefully dialed in would appear to simulate the panning 'fan' motion. Perhaps that is a means to avoid panning....

 

[Reed Lukens]

Gold is on the bedrock, so dig out an area with a shovel, it's 10 times faster, then clean out the cracks and hard packed layers with the dredge. Without a picture, I'm assuming that your using a suction nozzle. Throw the hoses over your leg and hold them to your side with your elbow, leaving your hand free to move the nozzle by the tip. Then hold the tip of the nozzle and curl a finger inside the front of it so you can feel the rocks and this keeps the large ones from going through. This will basically eliminate your plug ups because you will be feeling every rock that you let through the nozzle. Plug up's have to be dealt with but reducing the number of them is the key.

 

[specksandflecks]

If it's "allowed" you might consider re-purposing what you can into a 2.5 or 3". If you plan on mostly using suction you might consider a flair. Can't tell without pics but I think a flair would help get you lower. Keeping that suction hose as flat and straight as possible does make a difference. This video of my 2.5 suction nozzle dredge might give you some ideas. It can move a bit more material and is still fairly portable. Edit -Most of this short video was filmed out of frame, the cameraman was fired.

 

[Hoser John]

I do not get plugups on any given day, maybe 1 a week or so in a 60 hour week. Watch your flow and any time you see ANY slowing simply pop your hand across the nozzle for a second and that semi plug unclogs and away you go. When using a nozzle this works great on puddle pumpers but get past a 4" and OUCH they can bite. This is where the offset nozzle ring is fantastic as you simply pop off oversized rocks instead of a wrestling match with a flush nozzle. Experience will lessen your load and increase your take as time flows on. I run over/under dredges with a large ramped up punch plate so all smaller gold that would be affected by a surge is already down below and safe in the bank protected-tons a au 2u 2-John