Sep 05, 2013, 11:39 PM
help with angle.
I'm wondering what angle do you run your sluice in your dredge? Do you go with the 1"-1' drop like with normal sluicing or is it different with a dredge?
The reason I'm asking is I'm getting a little more build up in my sluice than I would like. It's not causing any gold loss that I have found, but it's leaving me with an excessive amount of cons to clean up. It just seems like something isn't just right, so I'm looking to make some minor adjustments. Everything else is finally running like I want so I don't want to make the wrong move here and mess things up elsewhere in the set up.
Here's my current set up
3" homemade dredge, it runs on a keene p180 pump powered by a 5.5hp Honda motor. My sluice is 14x48" the top section is ribbed rubber under a 3/8 punch plate. Below that I have a traditional riffle set over 3/4" raised expanded metal over hog moss miners moss.
Currently it's right about at that 1" of drop for every 12" of sluice. I'm catching good gold, and catching it in the right spots, but my sluice does fill up pretty good. To the point that I clean out the sluice every time I fill the gas tank (probably once every 1 1/2-2 hours) I'm new to all of this so I don't know if that is normal or not, but it seems a little much to me. If it's normal then I guess I'll leave things be, but if there is something I'm doing wrong I'd like to know.
Sep 05, 2013 11:39 PM
Sep 06, 2013, 05:55 AM
#1... If your recovery rate is good don't do a thing and just find a way to can your cons better / easier/ faster.
We often have 5 - 30 five gallon buckets of cons to work from our ops at the end of the week.
We just use a cleaning system that reduces all that down to about 1 quart.
Takes about 1 minute per gallon.
Test.... Test... Test...
It's not easy to do with a floating dredge... but I would increase your angle to where you are happy with the sluice holding pattern.
Run for about 20 minutes.
Have someone get a TUB and hold it at the end and capture 100% of your tailings.
Get some material or make it with a bunch of VERY fine gold in it.
Dump it on the creek bed and run it, and keep running for about 1-2 minutes.
Stop and test the tailings.
If you see a capture rate you are happy with on VERY fine gold... you're good to go.
Trust me... it's not easy to do and often takes 3 people total.
However... you can never DEFINITIVELY say your capture rate until you do it.
We do it on EVERY dredge and system we run.
Once you're done that it will be OFF YOUR MIND and you can focus on production.
Sep 06, 2013, 06:54 AM
Doc is the man!
As doc mentioned testing your tailings! but a single pan isnt a great indicator. Lets say you move a full yard of material and do 1 test pan and find nothing. that is not a very good sample of your material.
Also I hate to sound like a broken record but your angle is effected by many factors. Each manufacturer has a " starting place" but will require fine tuning afterwards. The angles are quite different between manufacturers and mats and sluice design. For example my Proline requires 3/8 to 1 inch drop over the ENTIRE box. It also depends on material your running and throttle setting. A general rule of thumb is the flatter you run your box the more fine gold you'll catch but the trade off is a buildup of lighter material as well. It's a balancing act.
Really dredges aren't known to capture fine gold excellent anyways. You may have to accept a tiny amount of loss vs. the amount of material your processing. I don't think anyone has 100% capture rate but I could be wrong.
If your worried about how much material your building up in your box then stick your goggles in the water near the end of the box and make sure you can see material dancing.
This means you have an active exchange happening. You should not see too much of your miners moss but at the same time you don't want to bury it completely. You want to just barely see it. Other than that you can change your angle by a SMALL AMOUNT and do your testing and see.
I know a few old guys that have told me to watch the biggest rocks that go through your box. If the rock kind of "walks" down the box and pauses for a split second at each riffle the your running decent. I don't know how accurate this method is but it seems to be true for my box.
Best advise is listen to Doc. Make a gold trap at the end of your box and after a good run spend the time and do some real testing. It takes alot of time and sucks but is necessary especially on a home made dredge. I force myself to spend a few hours or Mabe even a day and do testing every couple months or if I make a change to the box of any kind.
Taking the time now will pay dividends in the end. Not only will you run with confidence but you should catch more gold overall.
Last edited by Sick4gold; Sep 06, 2013 at 06:18 PM.
Sep 09, 2013, 08:04 PM
A tank of gas only last you 1 1/2 to 2 hours? I would be taking that thing in to a shop and have it worked on. Honda's are great on fuel eco. I have a Subaru ex17, running at 2280 rpms and I can get almost 6 hours on a tank.