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Spring dredging on the Arkansas

PostPosted: Sun Apr 29, 2012 10:07 am
by rocketsngold
Just got back from a quick trip up to the Arkansas for some spring dredging. On monday the river was low and WARM, believe it or not. Then the water started coming up and getting colder and cloudier through the week. I'd normally make this trip in early May, but work prevented that this year. I thought I'd freeze going this early, but seems like it's a warm year this year, so I got lucky.

I bought some of that new Gold Hog rubber matting and used it in my dredge. The spot I was dredging this year had LOADS of black sand, even a lot for the Arkansas. I haven't started cleaning up the cons yet, we'll see if that matting is good at exchanging material as claimed. It doesn't clog up with light material, that's for sure...

John

Re: Spring dredging on the Arkansas

PostPosted: Mon Apr 30, 2012 11:32 am
by cobill
John, let us know how the Gold Hog matting worked for you and any tips: water flow, UR or Scrubber and where in the box, drop rate, etc. I purchased some UR and placed it in my 4" Keene 3-stage in the first stage under riffles and the entire third stage(lower box) under riffles..haven't run it yet, but watched all the videos and it looks great! :D

Bill

Re: Spring dredging on the Arkansas

PostPosted: Tue Jul 17, 2012 7:39 pm
by rocketsngold
Well, I guess I owe an update on my experience with the Gold Hog rubber mats.

So, here's how I used them: I have a keene 2.5 inch dredge, with a 5ft long 10 inch wide sluice box. (Yeah, a little weird, more about that later.)
I set up the sluice box with 1 ft of miners' moss under the classifier screen (a superstition I suppose, as I've always liked being able to pull the miners moss and quickly pan it to see how I'm doing. I also use a 3/32nd inch screen instead of the std 1/4 inch since there seems to be nothing even close to that coarse on my claim), So, below the miners moss in the remaining upper part of the sluice I put 4 of the gold hog scrubber mats followed by 4 of the UR mats. I used the UR mats under some home-made riffles and expanded metal, and later under expanded metal alone. Although I might have had more water flow than one is supposed to for the scrubber mats (its' in the videos in the Gold Hog website), I was reasonably pleased with their performance. The uppermost mat tended to get overwhelmed by the black sand, but the lower 3 were working as advertised I'd say. They don't catch much blond sand or lighter material at all. At clean up, they held the gold pretty well, and in about the quantity I would have expected. I was a little less pleased with the UR mat on the first attempt. When I had riffles in the sluice, I tended to catch lighter pebbles and such and even some blond sand behind the riffles. I messed with sluice box angles some to try to minimize this, but the UR mat didn't seem to exchange well enough with riffles and expanded metal. At cleanup time I did have gold down in the UR mat, but more lighter material than with the scrubber mat. After a day of running like that, I took the riffles out and ran coarse expanded metal over UR mat and then I didn't catch any pebbles and less blond sand. I suspect the UR mat would work better in a shallower water flow where it could generate more turbulence. In my 10 inch wide sluice box, I think I have more water depth than optimal.

Final impressions at the river were that you'll make about half of the concentrates you would with riffles and carpet, and it will be a better concentration of the "heavies". When I get a full day dredging in with riffles and carpet, I'll fill one of those yellow 3 gallon cat litter buckets to the rim with concentrates. With the Gold Hog mats I was down to 1/2 bucket. Certainly made packing out easier.

So back in Houston I've been processing the concentrates. I'd say I did no worse than with a more standard setup of riffles and carpet. Plus I have much less concentrates than if I'd used riffles over miners moss (which would be about twice that with riffles and carpet.) I have a spot on my claim that gives about a penny wt for 4 1 hr setups, and it seemed consistent with total recovery from a "conventional" setup. So, I don't think I really got any more gold per day than I would with a conventional setup, but the concentrates were better per volume. Probably means I could run longer without risking loss of values.

Since the river has been so low this summer, I got in 2 more days dredging around the 4th of July. I switched my setup again, this time trying a foot of the Keene miracle mat just downstream of the miners moss, and then running coarse expanded metal over green carpet. I made the switch because I had encountered some balance problems with the 5 ft long sluice (so much for my cleverness) and the relatively heavy Gold Hog mats. My 5ft long sluice is actually a little wider than 10 inches. To use a 4ft sluice (the std one for the 2.5) to get the balance right I had to switch as I didn't have any more Gold Hog mat material and I didn't want to cut the ones I had a second time. As with the GH setup, the upper part of the Keene mat also tended to get swamped by black sand, but the lower parts were really collecting gold. And it's sometimes tough to get that keene mat to let go of the finer stuff. So, It seems to work pretty well too. I'll be cleaning those cons up hopefully before the labor day trip, so I'll know what to run then...

Am I crazy for ditching my riffles on a fine-gold-only river? I've started liking coarse expanded metal over carpet or UR mat.... The concentrates are almost 100% black.... (the remaining bits are the more favorable color!). Oh, on top of that I made a setup where I catch some magnetite with magnets attached to the damper to reduce the volume of that crap I have to run through the sluice. Dunno if that helps other than psychologically....

John

Re: Spring dredging on the Arkansas

PostPosted: Wed Jul 18, 2012 4:29 am
by russau
very good report John! my dredge has had similar results useing raised expanded over Veranda carpet on my over under sluice. i have 4 riffels at the end of my upper sluice for just in case situations,but never have them! last year on the Beans and Bacon claim i was impressed with the lack of cobbel and blond sand that built up in my sluice. and yep, i got also about 1/2 the cons i would normally get with full riffels and Miners Moss in the box,plus my dredge lost a bunch of weight! the GH mats seem tobe doing alright for you guys that have it, but the cost of it right now is prohibitive for me plus the last i read about it was that it only came in certain sizes.this may have changed???? well this year when you return to the river ,youll be able to run strong and not have the worry of loading up with blondes and B.S....