Afriscot Posted August 3, 2012 Report Share Posted August 3, 2012 Being involved in mostly metal detecting and limited time with sluices and black sands, I am asking for some ideas. A friend just called me and his father in law owns a gravel company. They put a sluice in because they heard there might be gold. They ran for a few months and got over 20 ounces of gold. The problem they asked me, is which is best recovery method for getting the very fine gold out of the black sands. I know one question will be how much black sands and I don't have that answer right now but will find out. I figured I would post this question because you guys and gals are the real experts. I thank you in advance for your help on this. Quote Link to comment Share on other sites More sharing options...
Grubstake1 Posted August 3, 2012 Report Share Posted August 3, 2012 I'd use a big, viberating table, I'm sure they have loads of black sand, that would be the way to recover the most gold fast. when I worked on the Merced River at Bagby, my boss had one he used, it was 8 foot long, and 6 foot wide, custom made, it had an electric motor with a belt drive to work an off set ajustable weight, that allowed you to set the viberation rate, also a valve on the water pump to ajust it. It was a slate table. which is best for recovering the gold. Grubstake Quote Link to comment Share on other sites More sharing options...
Admin nuggethunting Posted August 3, 2012 Admin Report Share Posted August 3, 2012 Hey Scott, Well it's always been my understanding, even when I was in college, that you couldn't mine precious metals (gold, silver) along with a sand and gravel operation. It was one or the other, and if caught it could mean huge fines. I'm hoping the owner of the operation understands this, if not, he needs to look into it. There might be ways around it now, to operate a sand and gravel operation along with a placer operation. Hopefully some others might now more. Quote Link to comment Share on other sites More sharing options...
Grubstake1 Posted August 3, 2012 Report Share Posted August 3, 2012 Rob I don't know about AZ, but here in Calif, they are very commond, in fact the Black sand storage on one on the Merce3d river at Snelling has been robbed a few times, they did catch a couple of guys last year, they were doing it at night. Grubstake Quote Link to comment Share on other sites More sharing options...
matt Posted August 3, 2012 Report Share Posted August 3, 2012 Tiechert construction in Sacramento gets the majority of their gravel as a by product of their gold mining. Rumor has it that they have never sold any of the gold. Quote Link to comment Share on other sites More sharing options...
Reno Chris Posted August 3, 2012 Report Share Posted August 3, 2012 They need to talk with someone who knows what they are doing when it comes recovering gold from sand and gravel operations. While a lot of guys here know about metal detecting or dredging, recovering gold from a gravel operation is a whole other ballgame. If they have a wet sand screw, they need to re-dig the spot where they dump the material when they clean it out - it may have several hundred ounces if they have been working there a long time. That is the point where gold accumulates in many gravel plants. On the other hand, not all plants produce a washed sand product, so not all have such a screw. They need to get an equipment supplier they can trust to get the right equipment adapted to their plant (it depends on what types of aggregate products they produce).Anyway, asking folks who dont really know much about aggregate processing is probably not such a great idea as it seems like they are clearly looking at a very valuable by-product. Quote Link to comment Share on other sites More sharing options...
AZNuggetBob Posted August 3, 2012 Report Share Posted August 3, 2012 I agree ChrisThere are just too many variables here. I've set up and operated several large placer plants and a sand and gravel for the Az. CAP canal, and each one needs to be tailored to a given situation. generally speaking black sand can be processed in several different ways with different types of equipment. jigs,shaker tables,filter presses,centrifuges,magnetic separators, rolling mills. need to know how many TPH, GPH. water available. etc. and this only covers gravity separation. you can also chemically separate it but is more expensive and involves more red tape. I also agree about the sand screw. We dismantled a plant and took 40 oz.'s of gold out from under a small bucket line stacker in a few shovels of concentrate. AzNuggetBob Quote Link to comment Share on other sites More sharing options...
moonlight Posted August 8, 2012 Report Share Posted August 8, 2012 we have done this recovery with a table we got from sierra metal fabricators in nevada city that is the same table they us at gravel plants around marysville here in cal we have one in are hard rock minning operation. golden one have a great day.. Quote Link to comment Share on other sites More sharing options...
AZNuggetBob Posted August 11, 2012 Report Share Posted August 11, 2012 My favorite line up and least expensive of all the equipment is run the black sands thru a rolling mill (rock crusher), this frees the gold attached to the black sand. then thru a magnetic separator, this pulls all those irons out so its not competing with the gold across a shaker table and also dramatically raises the volume that can be run per hour. and by all means stay away from those cheap Chinese made centrifuges, their junk! and wont last six months.Take care out there, AzNuggetBob Quote Link to comment Share on other sites More sharing options...
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