How much wood, could a woodchuck chuck, kinda

[easy goer]

Happy New Year,

I have a question for all you experienced dredgers and yes I know their is no "right answer".
Here goes!
How many yards per hour can you dredge under ideal conditions? I know, I know what do you mean by ideal? Depends on the dredge. Depends on the depth. Depends on the size of the rocks. Boulders. Current.

I am already shooting holes in my own question. I am looking for some answers from people who have way more experience than I do. Be as general or specific as you would like to be.

My situations this, water depth 2-5 feet, current not really an issue, overburden 2-7 feet to bedrock, lots of gravel and small rocks, fair amount of flat rocks that can cause a plug up, some large rocks 16" to 24" in diameter, occasional boulder that would require winching to move.

My dredge is an 8" Proline, 25 feet of hose, 12 foot sluice box.

Fire away! What did I miss?

Easygoer

[Joe S (AK)]

Hmmm - maybe how many pancakes and how much coffee you had for breakfast?

You're right, WAYYYYYYYY too many variables - but here are some thoughts:

first off, on air or not on air. 2' to bedrock or 7' to bedrock means sometimes yes and sometimes no
how compact the gravel is and does it sluff off into the dredge hole or not
clay in it's many forms with all it's headaches
How cold the water is (If'n you got-a take warm-up breaks)
condition, age and past maintenance schedule of equipment and operator
is the pay in specific layers or throughout the entire gravel
tree roots, leaves or grass
12 foot long but how wide sluicebox with what manufacturer's recovery mats
hogging and possibly not using enough (or too much) water to clear your riffles or catchments
character and configuration of the bedrock
round river rock, angular gravel, shale or maybe even siltstone
will you have to hand clear away larger rocks from in front of the nozzle
will you have to hand clear rocks from the sluice hole ("Big Rocks = Big Gold")

YIKES, the list goes on and on!

Remember the Psychiatrist / character "Dr. Sidney Freeman" who said, twice, on *M*A*S*H* "Ladies and gentlemen take my advice, pull down your pants and slide on the ice."
meaning
Don't worry so much about planning but rather just go do it and report what you found, afterwords.

Joe

[easy goer]

Joe,

Thanks for the reply! Point by point as best as I can.
Yes on air
Gravel doesn't slough but comes apart pretty easy
Clay towards the bedrock, not much
Water temp not too bad, and I have a hot water
New equipment
Old operator, pretty good shape
To this point gold is unseen in the dredging operation, its there but so small it is not visible. Anecdotally this is not always the case in this area, areas with "good gold" the gold is visible during dredging
No real grass or roots, no trees for sure
26" wide sluice, miners moss and riffles up top, standard from factory, last 6 feet, Gold Hog matting, River Hog, Talon and Scrubber, mostly Talon
Bedrock has plenty of cracks and crevices
Mix of round river rocks, lots a gravel
Yes moving big rocks by hand
Winch available to remove large rocks from hole.

Lastly, good advice on just do it! I get that. I am just curious as to what experienced dredgers under good conditions, bad conditions and optimal conditions run in an hour, roughly.

Is there some rule of thumb based on nozzle size? Obviously if you are moving pea gravel you can blow through it and will get maximum yardage. I am looking for some real world data from people who have done it.
"Well today went well I must have moved XX yards of material"
I realize the important part is moving material, fast or slow, that contains gold!!

It is winter here and not much else to talk about.


Easygoer

[easy goer]

And another thing?
Joe you got me thinking about this as well with the amount of water being too much or not enough.
Given the above parameters, after running 6 hours or so, how much cons would you expect to have? Reflecting on my earlier runs in 2023 I believe I was running it too flat. Probably ended up with somewhere between 5 to 7 gallons to process. First screen was 1/4" so more than half went away quickly. Just curious about what is "normal"

Easygoer

[chickenminer]

I think Keene figured their 8" dredge had a max capacity of 25 yph. So in real world Alaska conditions I would think about half that.
Miners always have a tendency to over-estimate the yardage they move

[DanAK]

A few thoughts on this..
My dredge will run 25-30 yards an hour before overrunning the sluice boxs (48’ of sluice) I have a mechanical dredge, surely you are referring to a suction dredge, both types share a few of the same principals the biggest being the tailings they generate, if your current isn’t a problem for diving it will be a huge factor in dispersing 25 yards per hour of tailings, just a few hours at that feed rate will have quite the pile of tailings built up, I would suspect the oversize rocks that would have to be moved by hand would also become a factor rather quickly also.
Just my .02c from an inexperienced suction dredger, keep us posted and Best wishes in the New Year !

[DanAK]

And also I’ll add after re reading this thread, I run about 200 yards per day and do a cleanup after 400 yards, three separate 24” by 16 foot sluice runs of expanded metal, a couple of nugget traps included yields about 10 gallons of minus 3/8” concentrates.

[Slatco]

Would love to see a pic of that sluice box Dan if possible.

[chickenminer]

Slatco .... Dan has videos in the Mining Videos thread.

[Joe S (AK)]

Yes Sir! That crafty 'ole Dan managed to sneak those video links (9 of 'em) right past me.

https://alaskagoldforum.x10host.com/php ... ?f=1&t=459

I've been to Dan's claims many times in the past and have always been inspired by his carefully thought out efforts every time. I have learned a lot from him over the years.

My wife and I once spent a couple of weeks there, one late summer / early fall and managed to have a rewarding full week plus watching a huge caribou herd migrate right through camp, some times two steps away. What a great thing that was!

Joe