I have asked a lot about this information before but not really with any proper data provided on our situation so here I go.
We have a creek we are looking to dredge, most of it has been mined recently other then some gullys that havent been touched since the rushes but these gullys are very very rich, we are making very good gold out of it just by going by hand, last trip 20 buckets (probably about 1 cubic metre of ground) yielded about 4 grams and we didnt even prospect for more then quater of an hour.
I have finally encouraged my prospecting partner to get a dredge, he thinks a 2 inch but I think that would be a waste of money as it wouldnt really be any faster right?
I am thinking a 4 Inch dredge as it would be a lot quicker and it could still fit in the creek, but as I said they are small gullys and im not sure a 4 inch would beable to function, here are some pictures of the creek after a medieum rain, this is probably about double the flow when it is normal or low, but it can get about double this again during a heavy flood. Looking at the creek like this would a 4 inch be suitable or would it just not fit or work even in higher water ?
Also would it be to rocky to be efficent for a dredge? That is a picture of the matirel above, there arent many big boulders but lots of medieum rocks ( some of the larger ones of the left there )
That there is pointing to the spot we got really good results at, it was pretty much just the middle of the river, there was very slight inside bend where the gravel was a bit higher but that was it .
Thanks so much for any info it is really appreciated .
A four inch without doubt in my view. You can dam that creek real quick to gain enough water to float a four inch. When you start dredging throw all the big rocks out on the bank, Pretty soon you will you will have heaps of floatable water, And can just chuck the rocks behind you. No matter what size dredge you are always going to have to hand chuck rocks, even with an eight or 10 inch dredge. The formula is, the smaller the suction intake then the more rocks you will have to hand handle. Damming is easy, make a wall of rocks across the creek the higher the better. Dont worry about the water flowing through your dam, course it will. Have with you a good length of black or clear plastic film from mitre 10 etc. Bang it in along your dam and it will cling like an octopus. Now you will be dredging in a lake with little flow. As you have slowed the current down you will tend to murk out. Not a problem. Contact me when and if you do, and I will give you an easy fix to sort out murking. Have done heaps of small creeks over the years, even ones smaller than that one, without a problem, even using a five inch.
I forgot to add get a four inch dredge with a suction nozzle as opposed to a power jet. Reason being, a suction nozzle will prime (suck) in a few inches of water. A power jet requires a lot deeper water to prime, as the flare the pressure hose goes into is on quite an angle requiring deeper water for it to be submerged where the pressure inlet is and thus prime and suck. A power jet is indeed more efficient than a suction nozzle. But at the depth you will drive down into in that small creek a suction nozzle will be ideally suited .
Would you have the dredge sitting over the dam and going downstream and wouldnt that stop it from getting murky? Or does it still get murky even if you are dredging the tailings downstream .
Well Dilllon you could start with the sluice section over hanging the dam. But as you dredge you will be moving the dredge forward, so that won’t work anymore. Eventually your tailings heap will also have a damming effect.
Will explain the anti murking method tonite. Working on my home built gold system to day. So will be busy plastic welding, fabricating and taxing my old brain. I will add some pictures etc in a day or two in the thread playing in the paddling pool.
I wouldn’t bother with a dredge, the last thing you want to do when chasing bedrock is raise the water level, you want to get it as low as possible so you can snipe the bed after, get a highbanker with 3” or 4” suction nozzle hopper, hand stack all the big rocks on some clean bedrock and set the highbanker up there, all the tailings will deposit on your stack and keep the water level low, also gives you a chance to run a detector over the tailings and test pan is way easier. Another bonus is carrying way less equipment into the area, 1 guy can easily walk in a banker and motor.
Thanks for the info, would a highbanker with a 4 inch nozzle be as quick as a dredge ? And would it be more expensive to get or cheaper ( just wondering as I don’t know much about highbankers with suction nozzles ) . Also is the sniping still valid if the bedrock is just a clay layer with few cracks and crevices and mostly flat with a few deeper holes ?
It is a dredge on legs, exactly the same except the water pumps a little higher.
A new shop purchased 4” dredge with dive gear is around $7000! A dredge highbanker with decent suction pump would be around $2500.
The bedrock will be under that clay layer, Your talking about false bedrock - gold still gets stuck on top of false rock but punch through to the real bed and you’ll find pockets of gold in those cracks your talking about. I’ve found some of my best gold in creeks like that, literally scraped the clay away and found a hole filled with nuggets, the hole was only 150mm deep and 300mm long but was covered in a smooth hard pack layer that looked like solid rock, stuck a screwdriver into it and nuggets started falling out.
Wow that Is a lot better might as well pick up one of those once I get round to it ! Are you sure that the clay is not the bottom layer as it is very hard and we always get our best results once we reach it, and it is at least 20CM thick probably more, and if there is gold below it wouldnt have the old timers already got down past the clay and picked up nuggets below it ? Or did they never punch through the clay and is there still riches underneath it? Sorry I always just thought that the bottom was either a clay layer or a bedrock layer.
( also in that gully where the pictures are from the clay layer is between 40-70Cm deep below the water level)
Clay can come from hydrolic elevator mining or can be just a natural deposit, either way I don’t stop until rock. Clay liquifies in earthquakes and moves/changes density in certain situations so any gold inside or on top travels through it. The only thing you can do is test an area to see if it’s worthwhile.
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